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Surgical treatment of fractures of the zygomaticomaxillary complex: effect of fixation on repositioning and stability. A systematic review

Open AccessPublished:July 19, 2021DOI:https://doi.org/10.1016/j.bjoms.2021.07.006

      Abstract

      Management of zygomaticomaxillary complex (ZMC) fractures can be challenging. Consequently, there is a difference in treatment amongst clinicians. In the literature it remains unclear if the number of fixation points affects the quality of the anatomical reduction, stability through time, and potential complications. Therefore, the objective of this study was to assess the outcome of no fixation, one-point fixation and multiple-point fixation of ZMC fractures. MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials were searched to identify eligible studies. After screening 925 articles, 17 studies fulfilled the inclusion criteria. Based on this systematic review no clear conclusions can be drawn on how stability, repositioning, and postoperative complications are affected by the number of fixation points. Nevertheless, it can be concluded that the advantage of multiple approaches is direct visualisation, and the downside is potentially approach-related complications. This review suggests that intraoperatively assisted cone-beam computed tomography (CBCT) can help improve the quality of the repositioning and by minimising the number of fixation points, the number of postoperative complications could be further reduced.

      Keywords

      Introduction

      The zygomaticomaxillary complex (ZMC) is an integral part of the facial structure and plays an important functional, structural, and aesthetic role in the mid-facial contour and in protecting the orbital contents.
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      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
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      Zygomaticomaxillary complex fractures: diagnosis and treatment.
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      Essential Sports Medicine.
      Fractures involving the ZMC are among the most common maxillofacial traumas.
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      Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis.
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      Evidence-based medicine: evaluation and treatment of zygoma fractures.
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      Application of computer-assisted surgery techniques in the management of zygomatic complex fractures.
      Most ZMC fractures are caused by violent assaults, road traffic accidents, falls, and sport-related injuries.
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      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
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      • Vellone V.
      • Torre U.
      • et al.
      Maxillofacial fractures in the province of Latina, Lazio, Italy: review of 400 injuries and 83 cases.
      • Bogusiak K.
      • Arkuszewski P.
      Characteristics and epidemiology of zygomaticomaxillary complex fractures.
      Although ZMC fractures predominate in young adult males, there is geographic and sociodemographic variation in the incidence and aetiology of ZMC fractures, due to socioeconomic, cultural, and environmental factors.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Peretti N.
      • MacLeod S.
      Zygomaticomaxillary complex fractures: diagnosis and treatment.
      • Bogusiak K.
      • Arkuszewski P.
      Characteristics and epidemiology of zygomaticomaxillary complex fractures.
      Clinical decision making in the treatment of ZMC fractures can be challenging. Various treatment algorithms have been introduced; however, uniform consensus is still lacking.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      Theoretically, three treatment options are possible for ZMC fractures: an expectative policy, closed reduction without fixation, and open reduction with fixation at one or more buttresses.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      • Meslemani D.
      • Kellman R.M.
      Zygomaticomaxillary complex fractures.
      The primary goals when treating ZMC fractures surgically are anatomical reduction and a stable position to ensure the optimal postoperative aesthetic and functional results.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Kim S.Y.
      • Nam S.M.
      • Park E.S.
      • et al.
      Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      Reduction of the fracture can be realised through closed (stab-incision) and open reduction.
      Closed reduction is a common treatment option for ZMC fractures. The stability of reduction relies on interfragmentary bone support, combined with the assumption that there is no muscle traction on the ZMC. The limited visualisation of the fracture site has been implicated as a disadvantage, but the introduction of intraoperative cone-beam computed tomography (CBCT) gives a new perspective to this discussion.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      • Toriumi M.
      • Nagasao T.
      • Itamiya T.
      • et al.
      3-D analysis of dislocation in zygoma fractures.
      • Lerhe B.
      • Alshehri S.
      • Ferachon D.
      • et al.
      Tomographic osteometry of the zygomatic bone applied to traumatology of facial bones: preliminary retrospective study of zygomatic summit in 28 patients.
      Insight into the three-dimensional aspects of the dislocation patterns in zygoma fractures are essential for intraoperative control of the fractures.
      • Toriumi M.
      • Nagasao T.
      • Itamiya T.
      • et al.
      3-D analysis of dislocation in zygoma fractures.
      • Lerhe B.
      • Alshehri S.
      • Ferachon D.
      • et al.
      Tomographic osteometry of the zygomatic bone applied to traumatology of facial bones: preliminary retrospective study of zygomatic summit in 28 patients.
      Most surgeons agree that open reduction should be indicated in unstable situations or when closed reduction is not achievable.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      • Meslemani D.
      • Kellman R.M.
      Zygomaticomaxillary complex fractures.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      Proponents suggest that open reduction without fixation allows reduction under direct visualisation, since the periosteum is incised and elevated to expose all lines of fracture.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      It needs to be noted that multiple approaches are necessary to make it possible to expose all fracture lines. However, exposure of the fractured segments and complete overview is not considered a part of management in all types of fractures. If open reduction is chosen, the standard treatment mostly involves internal fixation with titanium plates and screws to achieve stability.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      Several authors have suggested that the number of fixation points should be based on several factors: the displacement of the fracture segment, the type of fracture, and the stability of the ZMC after reduction.
      • Kim S.Y.
      • Nam S.M.
      • Park E.S.
      • et al.
      Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      It has been reported that one-point fixation realises enough stability,
      • Kim S.Y.
      • Nam S.M.
      • Park E.S.
      • et al.
      Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis.
      • Meslemani D.
      • Kellman R.M.
      Zygomaticomaxillary complex fractures.
      whereas others have reported that multiple fixation is essential to prevent inferior displacement, which can result in facial asymmetry.
      • Kim S.Y.
      • Nam S.M.
      • Park E.S.
      • et al.
      Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis.
      • Meslemani D.
      • Kellman R.M.
      Zygomaticomaxillary complex fractures.
      • Panchanathan S.
      • Saranathan M.
      • Kamalakaran A.K.
      • et al.
      Functional evaluation of the behavior of masticatory muscles in zygomaticomaxillary complex fracture: a prospective study.
      It remains unclear whether successful and predictable outcomes can be achieved with more fixation points on ZMC fractures, and if the number of fixation points affects the quality of the anatomical reduction, stability through time, and the potential complications. We carried out a systematic review of the literature to gain more insight into clinical decision making in the surgical treatment of ZMC fractures. We also wanted to assess what affects the quality of reposition that is needed to achieve adequate stability and reduce the number of complications. Therefore, we assessed the outcome of no fixation, one-point fixation, and multiple-point fixation in the management of ZMC fractures.

      Material and methods

      Protocol development

      A protocol was developed a priori to answer the following question: What are the outcomes of no fixation, one-point fixation, and multiple point fixation when managing ZMC fractures, especially regarding malar symmetry and stability? This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
      • Shamseer L.
      • Moher D.
      • Clarke M.
      • et al.
      Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation.

      Information sources and search strategy

      The search strategy was developed with the help of a biomedical information specialist according to the syntax rules of each database (Table 1). A literature search of the following electronic databases was conducted: MEDLINE (1964-2021), EMBASE (1947-2021) and the Cochrane Central Register of Controlled Trials (CENTRAL; inception to 2021). The automated search was supplemented by manually searching the references of relevant review articles and eligible studies for additional useful publications.
      Table 1Search strategy.
      DatabaseStrategy
      Medline(“Zygomatic Fractures”[Mesh] OR zygoma*[tiab])

      AND

      (“Fracture Fixation, Internal”[Mesh] OR fixat*[tiab] OR osteosynthes*[tiab] OR plate*[tiab])

      AND

      (1 point[tiab] OR one point[tiab] OR 2 point*[tiab] OR two point*[tiab] OR 3 point*[tiab] OR three point*[tiab] OR 4 point*[tiab] OR four point*[tiab] OR fixation point*[tiab] OR point fixation*[tiab] OR stability[tiab] OR malar[tiab] OR symmetr*[tiab] OR asymmetr*[tiab] OR form[tiab] OR singl*[tiab] OR multi[tiab])
      Embase('zygoma arch fracture'/exp OR zygoma*:ti,ab)

      AND

      ('osteosynthesis'/exp OR fixat*:ti,ab OR osteosynthes*:ti,ab OR plate*:ti,ab)

      AND

      (“1 point”:ti,ab OR “one point”:ti,ab OR “2 point*”:ti,ab OR “two point*”:ti,ab OR “3 point*”:ti,ab OR “three point*”:ti,ab OR “4 point*”:ti,ab OR “four point*”:ti,ab OR “fixation point*”:ti,ab OR “point fixation*”:ti,ab OR stability:ti,ab OR malar:ti,ab OR symmetr*:ti,ab OR asymmetr*:ti,ab OR form:ti,ab OR singl*:ti,ab OR multi:ti,ab)
      Cochrane([mh “Zygomatic Fractures”] OR zygoma*:ti,ab)

      AND

      ([mh “Fracture Fixation, Internal”] OR fixat*:ti,ab OR osteosynthes*:ti,ab OR plate*:ti,ab)

      AND

      (“1 point”:ti,ab OR “one point”:ti,ab OR “2 point*”:ti,ab OR “two point*”:ti,ab OR “3 point*”:ti,ab OR “three point*”:ti,ab OR “4 point*”:ti,ab OR “four point*”:ti,ab OR “fixation point*”:ti,ab OR “point fixation*”:ti,ab OR stability:ti,ab OR malar:ti,ab OR symmetr*:ti,ab OR asymmetr*:ti,ab OR form:ti,ab OR singl*:ti,ab OR multi:ti,ab)

      Eligibility criteria

      To be eligible, the studies had to meet the following criteria:
      • 1.
        Type of patients or population: adult patients with zygomatic fractures requiring closed reduction without fixation, or a surgical fixation treatment method with titanium plates and screws.
      • 2.
        Type of intervention: three-point fixation (zygomaticomaxillary buttress fixation method with infraorbital rim and frontozygomatic sutures).
      • 3.
        Comparison or control group: closed reduction without fixation or, one-point fixation or two-point fixation (zygomaticomaxillary buttress and/or infraorbital rim or frontozygomatic).
      • 4.
        Principal outcomes: the form and/or function of the ZMC complex.
      • 5.
        Outcomes: facial symmetry, malar eminence (Grade I, II, III), vertical dystopia, malar height, malar projection, displacement (horizontal and vertical), enophthalmos, diplopia, muscle traction (temporalis and masseter), stability, infection, infraorbital paraesthesia, sensory disturbance, repair operation, pain, periorbital swelling, limited mouth opening, scarring, operation time, haematoma, patient satisfaction, and cost of the plate.
      • 6.
        Study design: randomised clinical trials (RCT), prospective controlled clinical trials (CCT), cohort studies and case series.
      • 7.
        Study language: English.

      Exclusion criteria

      • 1.
        Studies with <15 patients.
      • 2.
        Use of biodegradable or other material such as titanium as a fixation plate.
      • 3.
        Panfacial fractures.
      • 4.
        Experts’ opinions, conference abstracts, letters to the editor, animal studies, reviews, and systematic reviews.

      Screening methods

      One reviewer (IR) initially screened the abstracts. Full-text documents were obtained of all the articles meeting the inclusion criteria. Full text analysis was performed independently by two reviewers (IR and LD).

      Data extraction

      The following data were extracted from the studies that met the above-mentioned criteria: author(s), year of publication, study design, country, number of patients, males/females, mean age, age range, follow-up (months), radiographic assessment/imaging technique, clinical assessment/symptoms, fracture site, number of fixation points (in combination with number of patients), site of fixation, description of ‘stability’, type of mini plate (material), and the variables mentioned in ‘Outcomes’.

      Evaluation of study quality and risk of bias

      The methodological quality of the included studies was assessed independently by two reviewers (IR and LD). The risk of bias of the randomised studies was assessed using the seven domains of the Cochrane Collaboration tool for RCT’s:
      • Higgins J.P.
      • Altman D.G.
      • Gøtzsche P.C.
      • et al.
      The Cochrane Collaboration's tool for assessing risk of bias in randomised trials.
      random sequence generation, allocation concealment, blinding of the participants and researchers, blinding of the outcome, incomplete outcome data, selective outcome reporting, and ‘other sources of bias’. These seven domains were graded as: low risk, unclear risk, or high risk of bias. The Methodological Index for Non-Randomised Studies (MINORS) was used to assess the methodological quality of the non-randomised studies.
      • Slim K.
      • Nini E.
      • Forestier D.
      • et al.
      Methodological index for non-randomized studies (minors): development and validation of a new instrument.
      This tool consists of 12 domains: a clearly stated aim, inclusion of patients, collection of data, appropriate endpoints, unbiassed assessment, follow-up period, loss to follow-up, calculation of the sample size, adequate control group, contemporary groups, baseline equivalence, and statistical analysis. The twelve domains were scored as: not reported (0), reported but inadequate (1), reported and adequate (2).

      Statistical analysis

      Data were extracted from all the included studies to investigate the management of ZMC fractures and their focus on stability and predictability in restoring malar symmetry. The postoperative evaluation results of no fixation, one-point fixation, two-point fixation, and three-point fixation were evaluated using descriptive statistics.

      Results

      Study selection

      The primary search of the period until February 1, 2021, resulted in 427 hits with the MEDLINE search, 461 with the EMBASE search, and 37 with the Cochrane search (Fig. 1). A total of 373 duplicates was removed, leaving 555 studies. After screening the titles and abstracts, 481 studies were excluded because they did not justify the exclusion or inclusion criteria. Checking the reference lists of the relevant reviews and scanning the eligible studies manually revealed three additional articles. This selection procedure resulted in seventy-six eligible studies for full-text analysis.
      Figure thumbnail gr1
      Figure 1Algorithm of study selection procedure.
      The analysis resulted in 15 studies being excluded because the predefined principal outcomes were not described. Another 16 studies were excluded because they used a material for internal fixation other than titanium plates and screws. Fourteen articles were excluded because there was no information about the number of fixation points, or detailed information could not be extracted. Nine articles were excluded because they were a part of a conference abstract. Two studies were excluded because they were reported in other language. And finally, three articles were excluded because the full text was not yet available. A total of 17 articles fulfilled the inclusion criteria.

      Characteristics of the studies

      The studies’ characteristics used for qualitative syntheses are depicted in Table 2. The number of patients varied from 15 patients
      • Jo T.
      • Kim J.
      An anthropometric and three-dimensional computed tomographic evaluation of two-point fixation of zygomatic complex fractures.
      to 245 patients.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      Eight articles described a prospective study with the mean follow-up varying from two weeks
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      to six months.
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      Of these eight articles, three described the outcome of open reduction with internal fixation (ORIF) using two-point fixation, three articles compared the outcome of ORIF using two-point fixation and three-point fixation, one article described the outcome of ORIF using one-point fixation, and one article described the outcome of ORIF using three-point fixation (Table 3). Five were retrospective studies with the mean follow up varying from 3.4 months
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      to one year.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      Of these five articles, one described the outcomes of no fixation, one described the outcome of ORIF using one-point fixation, two-point fixation, and three-point fixation, one compared the outcome of ORIF using two-point and three-point fixation, one described the outcome of ORIF using one-point fixation, and one article described the outcome of ORIF using two-point fixation. Four RCT studies compared the ORIF outcomes on applying two-point fixation and three-point fixation, with the mean follow-up varying from six weeks
      • Parashar A.
      • Sharma R.
      • Makkar S.
      Rigid internal fixation of zygoma fractures: a comparison of two-point and three-point fixation.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      to six months.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      Table 2General characteristics of the included studies. Data are number of patients unless otherwise stated.
      First author, year of publicationStudy designFollow up (months)Mean age (years)Males/ femalesNo. of patientsNo fixation1-point fixation2-point fixation3-point fixation
      Degala, 2021Prospective1.253321/324--1212
      Shokri, 2020Retrospective3.445.2132/30211-162--
      Mittal, 2019Prospective1.5NMNM20--20-
      Mahmood, 2019Prospective1.529.51 ± 9.2939/2160--3030
      Kim, 2018Retrospective4.444.8 ± 16.733/841-141413
      Nasr, 2018RCT3 & 62935/540--2020
      Dutt, 2018Prospective1.5NMNM40--2020
      Starch-Jensen, 2018Retrospective1242.2113/2914323---
      Latif, 2017RCT1.5NM14/650--2525
      Abu Dakir, 2015Prospective6NMNM30-30--
      Kumar Punjabi,2016Prospective0.5± 2514/620---20
      Balakrishnan, 2015RetrospectiveNM33.33213/32245--16475
      Jo, 2014Retrospective633.59/615--15-
      Ebenezer, 2014Prospective6NMNM20--20-
      Rana, 2012RCT1.585/1530,97100--5050
      Chakranarayan 2009Prospective1.529/120-3030--30-
      Parashar, 2007RCT321/128,622--108
      NM= not mentioned.
      Table 3Treatment procedure and material of the included studies.
      First author, year of publicationPlace of fixationType of miniplateDefinition of stabilityRadiographic assessment/imaging techniqueSurgical approach
      Degala, 20212-point: ZMB, FZB

      3-point: ZMC, FZB, IOR
      Mini plateNMCT (preoperatively, immediately postoperatively, 5-week postoperatively)ZMB: intraoral Keen’s incision

      FZB: Dingman’s lateral brow incision,

      IOR: infraorbital, transconjuctival incision
      Shokri, 20201-point: ZMBZMB: 2.0-mm mini plate fixationNMNM

      ZMB: intraoral vestibular approach
      Mittal, 20192-point: ZMB, FZBZMB: 2.0-mm stainless steel thickness

      FZB: 1.5-mm miniplate
      NM

      Radiographically (X-ray) at different intervals and for diagnosis (preoperatively and postoperatively)ZMB: intraoral approach

      FZB:

      lateral eyebrow approach
      Mahmood, 2019NMMini plateMalar height and mouth openingWaters' view, Caldwell's (X-ray) posterior-anterior view (preoperatively)NM
      Kim, 20181-point: ZMB

      2-point:

      ZMB, FZB

      3-point:

      ZMB, FZB, IOR
      ZMB: 2.0-mm mini plate and screws

      ZMB, FZB: 2.0-mm mini plate and screw+ 0.6-mm miniplate

      ZMB, FZB, IOR: 2.0-mm mini plate and screw+ 0.6-mm mini plate + 1.6-mm plate
      Orbital height and bilateral orbital width

      CT (preoperatively), 3D CBCT (immediately postoperatively and at least 3 months postoperatively)

      ZMB: upper vestibular incision

      FZB: transconjunctival incision

      IOR: lateral eyebrow incision

      Nasr, 20182-point:

      ZMB, IOR

      3-point:

      ZMB, FZB, IOR
      ZMB, IOR: 1.5 mm mini titanium plates

      ZMB, FZB, IOR: 1.5 mm mini titanium plates + mini L-shape plate
      NM

      3D CT-scan (preoperatively and 3 months postoperatively)

      ZMB: superior gingivobuccal sulcus (50%)

      IOR: subciliary approach (82.5%), transconjunctival approach (15%), and subtarsal approach (2.5%).

      FZB: pre-existing lacerations (12.5%), lateral eyebrow incision approach (52.5%) and extended subciliary incision (35%)

      Coronal approach (2,5%)
      Dutt, 20182-point: FZB, IOR

      3-point:

      ZMB, FZB, IOR
      Mini plate

      NMNMNM
      Starch-Jensen, 2018No fixation: reduction non-surgicalNo mini plate usedNMCT-scans (preoperatively and 1 year postoperatively)No surgical approach
      Latif, 20172-point:

      ZMB, FBZ

      3-point:

      ZMB, FZB, IOR
      ZMB, FBZ: 2mm mini plate

      ZMB, FZB, IOR: 2mm mini plate (ZMB, FBZ), 0.9 mm (IOR)
      NMX-ray (preoperatively), 3D CT-scan (6 weeks postoperatively)ZMB: buccal sulcus incision approach

      FBZ: lateral eyebrow incision

      IOR: subciliary incision

      Abu Dakir, 20151-point: ZMBZMB: Mini plates and 4 mm × 2.5 mm screwsNMX-rays peripheral nerve stimulation (preoperatively, immediately postoperatively and 6 months postoperatively)

      ZMB: intraoral vestibular approach

      Kumar Punjabi, 20163-point: ZMB, FZB, IORZMB, FZB, IOR: Non compression mini platesFacial asymmetry, limited mouth opening, diplopia, enophthalmosX-ray: Occipito-mental view 15, sub-mento-vertex view (preoperatively and 1 week postoperatively)

      ZMB: subgingival buccal sulcus approach

      FZB: lateral brow

      IOR: subciliary incisions
      Balakrishnan, 2015NMTitanium mini plates and screwsNMX-ray (preoperatively and postoperatively)

      NM
      Jo, 20142-point: ZMB, IOR0.4 mm thick plates (micro plate, Matrix midface plate, Synthes CMF)Superoinferior and anteroposterior displacement of the zygoma

      3D-CT (preoperatively and 6 months postoperatively)

      ZMB: gingivobuccal incision

      IOR: transconjunctival incision
      Ebenezer, 20142-point: FZB, IORMini plates and screwsNM3D CT-scan, PNS X- ray (preoperatively and postoperatively)

      FZB: lateral eyebrow approach

      IOR: infra orbital approach

      Rana, 20122-point:

      ZMB, FZB

      3-point:

      ZMB, FZB, IOR
      ZMB, FZB: 1.5 mm mini plates

      ZMB, FZB, IOR: 1.5 mm mini plates (ZMB, FZB), 0.9mm microplates (IOR)
      Malar height and vertical dystopia

      Waters' view, Caldwell's posterior-anterior view (preoperatively and 6 weeks postoperatively)

      ZMB: intraoral buccal sulcus incision

      FZB: lateral eyebrow incision or upper lid blepharoplasty incision

      IOR: subciliary incision or transconjunctival approach

      Chakranarayan, 20092-point: ZMB, FZBZMB: ‘L’ shaped titanium mini bone plate with two screws on each side of the fracture line

      FZB: 4- or 5-hole straight titanium mini bone plate with two screws on each side of the fracture line
      NMParanasal sinus view and submentovertex (preoperatively and 6 weeks postoperatively)

      ZMB: transoral vestibular incision

      FZB: ipsilateral lateral brow incision

      Parashar, 20072-point:

      FZB, IOR

      3-point:

      ZMB, FZB, IOR
      Non compression titanium mini plates

      Vertical dystopia, enophthalmos, malar projection and malar height

      CT (preoperatively and 3 months postoperatively)

      FZB: lateral brow incision

      IOR: subciliary incision

      ZMB: upper gingivobuccal sulcus incision

      NM= not mentioned in the article, ZMB= zygomatic arch and zygomaticomaxillary buttress, FZB = frontozygomatic buttress, IOR = infraorbital rim.

      Assessment of methodological quality

      The four included RCTs differed in follow-up time and outcome measurements.
      • Parashar A.
      • Sharma R.
      • Makkar S.
      Rigid internal fixation of zygoma fractures: a comparison of two-point and three-point fixation.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      The five retrospective and eight prospective studies also differed in follow-up time and outcome measurements. The risks of bias of the ‘random sequence generation’, ‘selective reporting’ and ‘other bias’ domains were low (Table 4). ‘Blinding of the participants and researchers’ and ‘blinding of the outcome assessment’ were found to have high risks of bias, since the participants and surgeons were informed and aware of the number of fixation points. Only one included RCT scored a high risk of bias in the domain ‘incomplete outcome data’, due to the fact that patients were lost to follow up.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      Subgroup analyses could not be performed because none of the RCTs scored a low risk of bias.
      Table 4Risk of bias assessment of RCT, prospective studies and retrospective studies. Cochrane Collaboration tool for assessing risk of bias of the includes RCT, MINORS (Methodological Index for Non-randomised studies) for assessing risk of bias of the prospective cohort studies and retrospective cohort studies.
      Cochrane Collaboration tool for assessing risk of biasMINORS
      Study name (year)Random sequence generation (selection bias)Allocation concealment (selection bias)Blinding of participants and researchers (performance bias)Blinding of outcome assessment (detection bias)Incomplete outcome data (attrition bias)Selective reporting (reporting bias)Other biasA clearly stated aimInclusion of consecutive patientsProspective collection of dataEndpoints appropriate to the aim of the studyUnbiased assessment of the studyFollow up-period appropriate to the aim of the studyLoss to follow up less than 5%Prospective calculation of the study sizeAn adequate control groupContemporary groupsBaseline equivalence of the groupsAdequate statistical analysis
      Randomised controlled trials
      Nasr et al (2018)LowUnclearHighHighLowLowLow
      Latif et al (2017)LowLowHighHighLowLowLow
      Rana et al (2012)LowLowHighHighHighLowLow
      Parashar et al (2007)LowUnclearHighHighLowLowLow
      Retrospective studies
      Shokri et al (2020)220201000000
      Kim et al (2018)210202201202
      Starch-Jensen et al (2018)210202001200
      Balakrishnan et al (2015)010000201000
      Jo et al (2014)210202200002
      Prospective studies
      Degala et al (2021)222202201000
      Mahmood et al (2019)222202221202
      Mittal et al (2019)222202200002
      Dutt (2018)212202201202
      Kumar Punjabi et al (2016)222201200000
      Abu Dakir et al (2015)112102200000
      Ebenezer et al (2014)222202200000
      Chakranarayan (2009)222202200000
      High: high risk of bias, Low: low risk of bias, Unclear: unclear risk of bias, 0: not reported, 1: reported but inadequate, 2: reported and adequate.
      Furthermore, all prospective and retrospective studies failed to use an unbiased assessment of the study endpoints and to report a baseline equivalence of groups (Table 4). Three prospective and three retrospective studies compared the difference in outcome between the number of fixation points and a control group. The other prospective and retrospective studies highlighted the outcome of a specific number of fixation points but did not have a control group.
      Eleven of the 17 included articles reported explicitly that they did not receive any funding or have any conflicts of interest.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Jo T.
      • Kim J.
      An anthropometric and three-dimensional computed tomographic evaluation of two-point fixation of zygomatic complex fractures.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      • Mittal G.
      • Garg R.
      • Sharma S.
      • et al.
      Efficacy of two-point fixation in the management of zygomatic complex fractures - a prospective clinical study.
      • Mahmood H.N.
      • Rahim A.U.
      • Khan W.U.
      Outcome of treatment of zygomatic bone fracture by two point fixation versus three point fixation in Mayo Hospital Lahore.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      • Dutt M.
      Comparison of 2 point and 3 point fixation of zygomatic bone fractures - a clinical study.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Six studies did not mention anything about potential funding or conflicts of interest.
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      • Parashar A.
      • Sharma R.
      • Makkar S.
      Rigid internal fixation of zygoma fractures: a comparison of two-point and three-point fixation.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      • Chakranarayan A.
      • Thapliyal G.K.
      • Sinha R.
      • et al.
      Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.

      Outcome measures of the included randomised controlled trials

      The RCTs included in this systematic review generally did not describe the same outcome variables and differed in follow-up time. Because of the high heterogeneity between the four included, the outcome measures could not be meaningfully pooled.
      All four RCTs compared two-point with three-point fixation. None of the outcome variables listed above was assessed by them and vertical dystopia was the only parameter described by three of them.
      • Parashar A.
      • Sharma R.
      • Makkar S.
      Rigid internal fixation of zygoma fractures: a comparison of two-point and three-point fixation.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      The results of their outcome measures are depicted in Table 5, Table 6. The overall outcomes of the three-point fixation was favourable compared to the two-point fixation of comparable ZMC fractures. This finding was based on the results of descriptive variables extracted directly from the RCTs. Only the cost of the plate was significantly favourable for two-point fixation, however patient satisfaction and operation time did not reveal significant differences between two-point or three-point fixation.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      The postoperative muscle traction of the masseter and temporalis variable was not significantly favourable for either three-point or two-point fixation.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      It has been implied that multiple point fixation leads to more stability, this was also seen in the results of this systematic review. Latif et al (2017) and Rana et al (2012) reported, respectively, that 76% and 80% of the patients with three-point fixation had stable fractures postoperatively, while only 28% and 32% of the two-point fixation patients had stable fractures postoperatively (Table 5).
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      Both of these studies reported a significant postoperative difference in malar height, vertical dystopia, and fracture stability between three-point and two-point fixation and concluded that three-point fixation is a favourable treatment modality for the management of ZMC fractures.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      Table 5Outcome measures of RCTs: malar symmetry and stability.
      Parameters

      I: malar asymmetry

      and

      II: stability
      Facial asymmetry (N/total population)Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade I (N/total population)
      Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade II (N/total population)
      Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade III (N/total population)
      Vertical Dystopia (mean ± SD; in mm, total population)Malar height (mean ± SD; in mm, total population)Malar projection (mean ± SD; in mm, total population)Enopthalmos (N/total population)Diplopia (N/total population)Muscle traction: temporalis (mean ± SD; in power, total population)Muscle traction: masseter (mean ± SD; in power, total population)Stable (N/total population)
      No fixation (No. patients)------------
      1-point fixation (No. patients)------------
      2-point fixation (No. patients)Nasr (2018)

      0/20; 0%
      Nasr (2018)

      13/20; 65%
      Nasr (2018)

      7/20; 35%
      Nasr (2018)

      0/20;0%
      Latif (2017)

      3.726 ± 0.931 (25)
      Latif (2017)

      66.875 ± 1.096 (25)
      Nasr (2018)

      2 ± 1.15 (20)
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      Nasr (2018)

      0/20; 0%
      Nasr (2018)

      0/20; 0%
      Nasr (2018)

      0.3 ± 0.12 (20)
      Nasr (2018)

      0.5 ± 0.16 (20)
      Latif (2017)

      7/25; 28%
      Parashar (2007)

      0/10;0%
      Parashar (2007)

      7/10;10%
      Parashar (2007)

      3/10; 30%
      Rana (2012)

      3.18 ± 1.003 (50)
      Rana (2012)

      66.72 ± 3.62 (50)
      Parashar (2007)

      3.5 ± 1.35 (10)
      Parashar (2007)

      7/10; 70%
      Rana (2012)

      16/50;32%
      Parashar (2007)

      2.05 ± 0.89 (10)
      3-point fixation (No. patients)Nasr (2018)

      0/20; 0%
      Nasr (2018)

      13/20; 65%
      Nasr (2018)

      7/20; 35%
      Nasr (2018)

      0/20;0%
      Latif (2017)

      2.473 ± 1.070 (25)
      Latif (2017)

      68.510 ± 0.858 (25)
      Nasr (2018)

      2.5 ± 0.7 (20)
      Nasr (2018)

      2/20; 10%
      Nasr (2018)

      0/20; 0%
      Nasr (2018)

      0.29 ± 0.09 (20)
      Nasr (2018)

      0.41 ± 0.11 (20)
      Latif (2017)

      19/25; 76%
      Parashar (2007)

      3/8; 37.5%
      Parashar (2007)

      5/8; 62.5%
      Parashar (2007)

      0/8;0%
      Rana (2012)

      2.36 ± 1.102 (50)
      Rana (2012)

      68.26 ± 3.76 (50)
      Parashar (2007)

      1 ± 1.06 (8)

      Parashar (2007)

      3/8; 37.5%
      Rana (2012)

      40/50; 80%
      Parashar (2007)

      0.81 ± 0.75 (8)
      1 Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      Table 6Outcome measures of RCTs: complications and clinical outcome in Nasr (2018).
      Parameters

      III: complications

      and

      IV: clinical outcome
      Infection (N/total population)Infraorbital paraesthesia (N/total population)Sensory disturbance (N/total population)Operation time (mean ± SD; in min, total population)Haematoma (N/total population)Patient satisfaction (mean ± SD; in %, total population)Cost of the plate (mean ± SD; in Egyptian pounds - Euros, total population)
      No fixation (No. patients)-------
      1-point fixation (No. patients)-------
      2-point fixation (No. patients)0/20; 0%6/20; 30%0/20; 0%71.11 ± 33.14 (20)0/20; 0%80.22 ± 10.83 (20)2.100 ± 670.8 – 109.06 ± 34.84 (20)
      3-point fixation (No. patients)0/20; 0%4/20; 20%0/20; 0%93.33 ± 24.01 (20)0/20; 0%78.4 ± 13.22 (20)3366.67 ± 668.3 – 174.80 ± 3471 (20)

      Outcome measures of prospective and retrospective studies

      Malar symmetry

      The outcome measures from the included prospective and retrospective studies were divided into four categories: malar symmetry, stability, complications, and clinical outcome. Facial asymmetry after surgery was reported in 13% of cases in the no fixation group by Starch-Jensen et al (2018), while facial asymmetry was reported by Shokri et al (2020) in none of the patients who had received one-point fixation (Table 7).
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      Ebenezer et al (2014), Balakrishnan et al (2015) and Degala et al (2021), respectively, reported facial asymmetry in 0%, 4%, and 50% of the patients who had received two-point point fixation.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      Facial asymmetry was reported by Kumar Punjabi et al (2016) in 30% of the patients who had received three-point fixation and Degala et al (2021) reported facial asymmetry in 8% of three-point fixation.
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      It should be noted that multiple point fixation is associated with more postoperative complications, such as scarring, which could also lead to facial asymmetry.
      • Mittal G.
      • Garg R.
      • Sharma S.
      • et al.
      Efficacy of two-point fixation in the management of zygomatic complex fractures - a prospective clinical study.
      There was almost no noticeable difference between two-point and three-point fixation in terms of malar eminence (Grades I, II, and III), however the difference between three-point and two-point fixation for the variable Grade III was reported as significant by Dutt et al (2018).
      • Dutt M.
      Comparison of 2 point and 3 point fixation of zygomatic bone fractures - a clinical study.
      Kim et al (2018) stated that there was no correlation in vertical dystopia between one-point, two-point, and three point fixation.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      On the contrary, Dutt et al (2018) reported a significantly lower vertical dystopia score in the three-point fixation group than in the two-point fixation group.
      • Dutt M.
      Comparison of 2 point and 3 point fixation of zygomatic bone fractures - a clinical study.
      Mahmood et al (2019) reported that mean malar height reduced in the two-point and three-point fixation group, but that malar height was significantly lower in the three-point fixation group.
      • Mahmood H.N.
      • Rahim A.U.
      • Khan W.U.
      Outcome of treatment of zygomatic bone fracture by two point fixation versus three point fixation in Mayo Hospital Lahore.
      Table 7Outcome measure: malar symmetry.
      Parameter I: malar asymmetryFacial asymmetry (N/total population)Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade I (N/total population)
      Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade II (N/total population)
      Malar eminence
      Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      : Grade III (N/total population)
      Vertical Dystopia (mean± SD; in mm, total population)
      Dutt et al (2018) and Mittal et al (2019) described the mean vertical dystopia (mean ±SD; in mm, total population) and Kim et al. (2018) described the mean changes of orbital height (mean±SD; in mm, total population).
      Malar height (mean ± SD; in mm, total population/ mean vertical difference: VD ratio)
      Mittal et al (2019) and Mahmood et al (2019) describe mean malar height) mean ±SD; in mm, total population) and Jo et al (2014) described mean vertical difference (mean horizontal difference: VD ratio).
      Malar projection (mean horizontal difference: HD ratio)
      No fixationStarch-Jensen (2018)

      3/23; 13%
      -

      -

      --

      -

      -
      1-point fixationShokri (2020)

      0/162; 0%
      ---Kim (2018)

      0.50 ± 0.10 (14)
      --
      2-point fixationBalakrishnan (2015)

      6/164; 4%
      Dutt (2018)

      5/20; 25%
      Dutt (2018)

      8/20; 40%
      Dutt (2018)

      7/20; 35%
      Kim (2018)

      0.47 ± 0.13(14)
      Mittal (2019)

      69.10 ± 4.35 (20)
      Jo (2014)

      0.989


      Ebenezer (2014)

      0/20; 0%



      Dutt (2018)

      2.10 (20)



      Mahmood (2019)

      58.07±4.61 (30)



      Degala (2021)

      6/12; 50%
      Mittal (2019)

      0.28 ± 0.55 (20)
      Jo (2014)

      1.019
      3-point fixationKumar Punjabi (2016)

      6/20; 30%

      Dutt (2018)

      6/20; 30

      Dutt (2018)

      9/20; 45

      Dutt (2018)

      5/20; 25%

      Kim (2018)

      0.47 ± 0.09(13)

      Mahmood (2019)

      57.20±3.96 (30)

      -
      Degala (2021)

      1/12; 8%
      Dutt (2018)

      0,94 (20)
      1 Malar eminence: Grade I: Excellent cosmetic result, no malar asymmetry. Grade II: Good cosmetic result, malar asymmetry on careful inspection. Grade III: Poor cosmetic result, noticeable malar asymmetry.
      2 Dutt et al (2018) and Mittal et al (2019) described the mean vertical dystopia (mean ± SD; in mm, total population) and Kim et al. (2018) described the mean changes of orbital height (mean± SD; in mm, total population).
      3 Mittal et al (2019) and Mahmood et al (2019) describe mean malar height) mean ± SD; in mm, total population) and Jo et al (2014) described mean vertical difference (mean horizontal difference: VD ratio).

      Stability

      Data for the stability parameters regarding horizontal and vertical displacement could be extracted from only one study and they found no significance difference between the number of fixation points and postoperative horizontal and vertical displacement.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      Starch-Jensen et al (2018), Shokri et al (2020) and Kumar Punjabi et al (2016) all reported that none of their patients showed enophthalmos (Table 8).
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      Degala et al (2021) reported no enophthalmos in the three-point fixation group and two patients with enophthalmos in the two-point fixation group.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      Table 8Outcome measure: stability.
      Parameter II: stabilityHorizontal displacement (mean ± SD; in mm, total population)Vertical displacement (mean ± SD; in mm, total population)Enopthalmos (N/total population)Diplopia (N/total population)Muscle traction: temporalis (mean ± SD; in power, total population)Muscle traction: masseter (mean ± SD; in power, total population)Stable fracture (N/total population)
      No fixation--Starch-Jensen (2018)

      0/23; 0%
      ----
      1-point fixationKim (2018)

      0.36 ± 0.05 (14)
      Kim (2018)

      0.36 ± 0.05 (14)
      Shokri (2020)

      0/162; 0%
      ----
      2-point fixationKim (2018)

      0.34 ± 0.08 (14)
      Kim (2018)

      0.34 ± 0.05 (14)
      Degala (2021)

      2/12; 17%
      ---Ebenezer (2014)

      20/20; 100%
      3-point fixationKim (2018)

      0.30 ± 0.08 (13)
      Kim (2018)

      0.36 ± 0.05 (13)
      Kumar Punjabi (2016)

      0/20; 0%

      Kumar Punjabi (2016)

      1/20; 5%
      ---
      Degala (2021)

      0/12; 0%

      Complications

      It appears that multiple fixation is associated with more postoperative complications, such as infection and nerve palsy.
      • Mittal G.
      • Garg R.
      • Sharma S.
      • et al.
      Efficacy of two-point fixation in the management of zygomatic complex fractures - a prospective clinical study.
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      Only two of the included studies reported on the variable infection; Shokri et al (2020) and Ebenezer et al (2014) both reported an infection rate of 5% (Table 9).
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      None of the patients reported infraorbital paraesthesia in the group no fixation and one-point fixation.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Infraorbital paraesthesia was reported in 17% of the cases in the two-point fixation group by Chakranarayan et al (2009) and in 4% of the cases in the three-point fixation group by Balakrishnan et al (2015).
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Chakranarayan A.
      • Thapliyal G.K.
      • Sinha R.
      • et al.
      Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture.
      Degala et al (2021) reported that infraorbital paraesthesia is more likely to develop with two-point fixation than three-point fixation.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      However, no significant difference was found. Both Starch-Jensen et al (2018) and Shokri et al (2020) reported that no patient required revision surgery after open reduction with internal fixation.
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      Table 9Outcome measure: complications.
      Parameter III: complicationsInfection (N/total population)Infraorbital paraesthesia (N/total population)Sensory disturbance (N/total population)Repair operation (N/total population)
      No fixation-Starch-Jensen (2018)0/23; 0%-Starch-Jensen (2018)

      0/23; 0%
      1-point fixationShokri (2020)

      8/162; 5%
      Abu Dakir (2015)

      0/30; 0%
      -Shokri (2020)

      0/162; 0%
      2-point fixationEbenezer (2014)

      1/20; 5%
      Chakranarayan (2009)

      5/30; 17%

      --
      Degala (2021)

      3/12; 25%
      3-point fixation-Balakrishnan (2015)

      3/75; 4%

      --
      Degala (2021)

      0/12; 0%

      Clinical outcome

      If one-point and two-point fixation are compared with each other on postoperative pain; one-point fixation scores better than two-point fixation (Table 10). Dakir et al (2017) reported that none of the one-point fixation patients experienced pain.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Pain after two-point fixation was reported by Balakrishnan (2015) in 4% of cases and by Chakranarayan (2009) in 3% of cases.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Chakranarayan A.
      • Thapliyal G.K.
      • Sinha R.
      • et al.
      Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture.
      Two-point fixation was reported to have a postoperative one-month periorbital swelling rate of 3%.
      • Chakranarayan A.
      • Thapliyal G.K.
      • Sinha R.
      • et al.
      Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture.
      Mean mouth opening was reported by Mahmood et al (2019) and a significant improvement in the three-point fixation group was observed compared to the two-point fixation group.
      • Mahmood H.N.
      • Rahim A.U.
      • Khan W.U.
      Outcome of treatment of zygomatic bone fracture by two point fixation versus three point fixation in Mayo Hospital Lahore.
      Dakir et al (2017) reported no scarring after one-point fixation, Ebenezer et al (2014) observed a scarring rate of 10% in the two-point fixation group and Balakrishnan et al (2015) reported a rate of 4% in the three-point fixation group.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Degala et al (2021) found that scarring was more likely to occur after three-point fixation than two-point fixation.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      However, no significant association was observed between the number of fixation points and postoperative scar.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      Furthermore, Ebenezer et al (2014) stated that 100% of the patients who had received two-point fixation were satisfied with the result achieved.
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      Table 10Outcome measure: clinical outcome
      Parameter IV: Clinical outcomePain (N/total population)Periorbital swelling (N/total population)Mouth opening (mean ± SD; in mm, total population)Scarring (N/total population)Operation time (mean in min, total population)Haematoma (N/total population)Patient satisfaction (N/total population)
      No fixation--Starch-Jensen (2018)

      49 (23)
      ----
      1-point fixationAbu Dakir (2015)

      0/30; 0%
      --Abu Dakir (2015)

      0/30; 0%
      Shokri (2020)

      35.5 (162)
      --
      2-point fixationBalakrishnan (2015)

      6/164; 4%



      Chakranarayan (2009)

      1/30; 3%
      Mahmood (2019)

      34.17±1.32 (30)
      Degala (2021)

      1/12; 8%



      --Ebenezer (2014)

      20/20; 100%
      Chakranarayan (2009)

      1/30; 3%
      Ebenezer (2014)

      2/20; 10%
      3-point fixation--Mahmood (2019)

      36.20±1.38 (30)
      Degala (2021)

      2/12; 17%

      ---
      Balakrishnan (2015)

      3/75; 4%

      Discussion

      This systematic review assessed the outcome of no fixation, one-point fixation, and multiple-point fixation in the management of ZMC fractures. The primary goal of treating ZMC fractures surgically is to achieve stable anatomical reduction, resulting in optimal postoperative aesthetic and functional conditions, and minimal postoperative complications.
      When considering adequate anatomical reduction, visualisation is a key factor. In this analogy, more surgical access allows the surgeon to inspect more of the fractured sites and, consequently, leads also to adequate anatomical reduction.
      • Bailey B.J.
      • Johnson J.T.
      • Newlands S.D.
      Head & Neck Surgery–otolaryngology.
      • Bagheri S.C.
      • Bell B.
      • Khan H.A.
      Current Therapy In Oral and Maxillofacial Surgery.
      • Rodriguez E.D.
      • Losee J.E.
      • Neligan P.C.
      Plastic Surgery E-Book: Volume 3: Craniofacial, Head and Neck Surgery and Pediatric Plastic Surgery.
      Although multiple approaches enable direct visualisation, the downside is the potential of inducing approach-related complications. Relatively high risks of postoperative complications are especially associated with approaches to the infraorbital rim and/or orbital floor (such as subciliary or transconjunctival approaches).
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      Thus, it is important to implement a treatment strategy that focuses on a predictable outcome and patient satisfaction, and not only on maximum exposure.
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      • Bagheri S.C.
      • Bell B.
      • Khan H.A.
      Current Therapy In Oral and Maxillofacial Surgery.
      • Rodriguez E.D.
      • Losee J.E.
      • Neligan P.C.
      Plastic Surgery E-Book: Volume 3: Craniofacial, Head and Neck Surgery and Pediatric Plastic Surgery.
      • Lee E.I.
      • Mohan K.
      • Koshy J.C.
      • et al.
      Optimizing the surgical management of zygomaticomaxillary complex fractures.
      • Kim J.H.
      • Lee J.H.
      • Hong S.M.
      • et al.
      The effectiveness of 1-point fixation for zygomaticomaxillary complex fractures.
      The introduction of intraoperative 3D imaging has changed treatment concepts for managing ZMC fractures.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      • Assouline S.L.
      • Meyer C.
      • Weber E.
      • et al.
      How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature.
      The adequacy of reduction can be addressed by intraoperative imaging instead of additional surgical exposure.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      • Assouline S.L.
      • Meyer C.
      • Weber E.
      • et al.
      How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature.
      Thereby more surgical approaches can be avoided and hence, potentially, reduce the amount of complications.
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      • Toriumi M.
      • Nagasao T.
      • Itamiya T.
      • et al.
      3-D analysis of dislocation in zygoma fractures.
      • Lerhe B.
      • Alshehri S.
      • Ferachon D.
      • et al.
      Tomographic osteometry of the zygomatic bone applied to traumatology of facial bones: preliminary retrospective study of zygomatic summit in 28 patients.
      Stability can be assessed by comparing the intraoperative scan with the postoperative images through time. Intraoperative CBCT will not help with the long-term stability but is necessary to assess stability through time. Several publications have shown that adequacy of reduction has been improved significantly when an intraoperative (CB)CT scan is used.
      • Wilde F.
      • Lorenz K.
      • Ebner A.K.
      • et al.
      Intraoperative imaging with a 3D C-arm system after zygomatico-orbital complex fracture reduction.
      • Zimmerer R.M.
      • Ellis 3rd, E.
      • Aniceto G.S.
      • et al.
      A prospective multicenter study to compare the precision of posttraumatic internal orbital reconstruction with standard preformed and individualized orbital implants.
      • Gander T.
      • Blumer M.
      • Rostetter C.
      • et al.
      Intraoperative 3-dimensional cone beam computed tomographic imaging during reconstruction of the zygoma and orbit.
      • Hoelzle F.
      • Klein M.
      • Schwerdtner O.
      • et al.
      Intraoperative computed tomography with the mobile CT Tomoscan M during surgical treatment of orbital fractures.
      Revision surgery due to an incorrect reduction can be minimised when intraoperative (CB)CT scans are used.
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      • Gander T.
      • Blumer M.
      • Rostetter C.
      • et al.
      Intraoperative 3-dimensional cone beam computed tomographic imaging during reconstruction of the zygoma and orbit.
      The question arises whether the avoidable revision surgery outweighs the disadvantages of CBCT scans. Intraoperative CBCT devices are expensive.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      Other disadvantages are the limited availability of intraoperative CBCT scanning and the radiation exposure.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      • Assouline S.L.
      • Meyer C.
      • Weber E.
      • et al.
      How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature.
      Scanning costs extra operation time, but can also result in a reduction of operation time when additional surgical approaches can be avoided. Interestingly, in this review, 12 studies verified the reduction postoperatively, but none intraoperatively. Only seven of the studies used 3D imaging preoperatively and postoperatively and seven of the included studies used a plain radiograph for preoperative and postoperative assessments. The difference in imaging techniques between the studies needs to be taken into consideration. Since none of the included studies applied intraoperative imaging, stability could only be assessed by comparing postoperative images through time.
      A second important aspect in the predictable treatment of ZMC fractures is stability (through time). Stability after ZMC fracture treatment can be defined as ‘a reduced ZMC fracture, which remains in a stable anatomical position over time’. Stability is assessed through time in this systematic review because we wanted to establish information about the demands of the osteosynthesis materials. Two requirements need to be mentioned with respect to this. Regarding a closed reduction, the interfragmentary bone support, with or without ORIF, must be stable enough to maintain the position and capable of withdrawing the forces applied to the ZMC. In this context, it is remarkable that most of the literature does not address the effect of the masticatory muscles on the stability of the ZMC in the presence of a fracture. From an anatomical perspective, the masseter muscle originates from the zygomatic bone and zygomatic arch, and the temporalis muscle passes medially to the zygomatic bone prior to entering the coronoid process and anterior ramus of the mandible.
      • Meslemani D.
      • Kellman R.M.
      Zygomaticomaxillary complex fractures.
      The forces generated by muscle activity can act directly on the ZMC fracture and can therefore, potentially, cause malar asymmetry and vertical dystopia.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      When evaluating treatment quality, most authors focus on stability as one of the main variables. However, none of the studies in this systematic review reported on the quality of the reduction. Inevitably, plate and screw fixation are often required to align fractures properly after high energy injuries characterised by comminution, injured periosteum, and severe displacement.
      • Lee E.I.
      • Mohan K.
      • Koshy J.C.
      • et al.
      Optimizing the surgical management of zygomaticomaxillary complex fractures.
      • Adam A.A.
      • Zhi L.
      • Bing L.Z.
      • et al.
      Evaluation of treatment of zygomatic bone and zygomatic arch fractures: a retrospective study of 10 years.
      A comminuted fracture of the zygoma has less interfragmentary support than a comminuted fracture of the mandibula, due to the muscle traction and force on the mandibula. In most cases, these comminuted fractures cannot be repositioned adequately by means of interfragmentary support, and therefore need fixation. Most of the included studies erroneously misinterpreted this requirement of fixation, in our opinion, as ‘lack of stability’. Of the included 17 studies, 12 reported on stability, but based on different definitions. Two studies assessed the stability through time, by comparing immediate postoperative images with those obtained several months later.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Kim et al (2018) described stability in terms of orbital height, bilateral orbital width, and horizontal and vertical changes of the screw. Stability was assessed by comparing immediate postoperative CBCT images with CBCT images obtained three months later. The one aforementioned study concluded that there was no significant difference in postoperative stability between one-point, two-point, and three-point fixation.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      It was stated that one-point fixation at the zygomatic buttress through upper vestibular incision is sufficiently rigid, as long as accurate anatomical reduction is achieved.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      The second study that assessed stability through time was by Abu Dakir et al (2017) who compared an immediate postoperative 2D radiograph with a six month postoperative radiograph, but they did not provide a definition of stability.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Another limitation of this study is that 2D radiograph was used for imaging, while 3D imaging is favourable for indication and evaluation.
      • Strong E.B.
      • Gary C.
      Management of zygomaticomaxillary complex fractures.
      • Ellis 3rd, E.
      • Perez D.
      An algorithm for the treatment of isolated zygomatico-orbital fractures.
      The third, and probably most important, aspect in the treatment of ZMC fractures is related to predictability of clinical outcome and complications. Multiple point fixation is expected to be associated with more complications than single point or closed reduction in relation to repositioning and fixation, or to the approach.
      • Mahmood H.N.
      • Rahim A.U.
      • Khan W.U.
      Outcome of treatment of zygomatic bone fracture by two point fixation versus three point fixation in Mayo Hospital Lahore.
      Enophthalmos and infraorbital paraesthesia are present more in patients who have had two- or three-point fixation than patients who have had single point fixation or closed reduction (Table 5, Table 6, Table 8, Table 9).
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      • Balakrishnan K.
      • Ebenezer V.
      • Dakir A.
      • et al.
      Management of tripod fractures (zygomaticomaxillary complex) 1 point and 2 point fixations: a 5-year review.
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      • Shokri T.
      • Sokoya M.
      • Cohn J.E.
      • et al.
      Single-point fixation for noncomminuted zygomaticomaxillary complex fractures - a 20-year experience.
      • Parashar A.
      • Sharma R.
      • Makkar S.
      Rigid internal fixation of zygoma fractures: a comparison of two-point and three-point fixation.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      • Chakranarayan A.
      • Thapliyal G.K.
      • Sinha R.
      • et al.
      Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture.
      • Degala S.
      • Radhakrishna S.
      • Dharmarajan S.
      Zygomaticomaxillary fracture fixation: a prospective comparative evaluation of two-point versus three-point fixation.
      This outcome could be explained by the more severe primary injury requiring more extensive fixation and not the result of the fixation method itself. The stability rate of 100% after two-point fixation reported by Ebenezer et al (2014) was not in line with our expectations, since Latif et al (2017) and Rana et al (2012) reported respectively that 8% and 32% of the two-point fixation patients had stable fractures postoperatively.
      • Ebenezer R.
      • Ramalingam B.
      • Sivakumar M.
      • et al.
      Treatment of zygomatic complex fractures using two point fixation under general anaesthesia.
      • Rana M.
      • Warraich R.
      • Tahir S.
      • et al.
      Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation–a randomised prospective clinical trial.
      • Latif K.
      • Alanazi Y.
      • Alrwuili M.R.
      • et al.
      Post operative outcomes in open reduction and internal fixation of zygomatic bone fractures.
      An explanation for this may be that the definition of stability differs in each study and/or the relatively small patient group. It needs to be mentioned that patient satisfaction is an important aspect of treatment success and yet only one study investigated and mentioned this variable.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      Nasr et al (2018) reported that patient satisfaction was higher with two-point fixation than with three-point fixation, but not significantly.
      • Nasr W.F.
      • ElSheikh E.
      • El-Anwar M.W.
      • et al.
      Two- versus three-point internal fixation of displaced zygomaticomaxillary complex fractures.
      This systematic review also encountered various limitations. The inconsistent follow-up durations, from two weeks
      • Punjabi S.K.
      • Channar K.A.
      • Kumar N.
      • Banglani M.A.
      • et al.
      Isolated zygomatic bone fracture; management by three point fixation.
      to one year,
      • Starch-Jensen T.
      • Linnebjerg L.B.
      • Jensen J.D.
      Treatment of zygomatic complex fractures with surgical or nonsurgical intervention: a retrospective study.
      makes it difficult to compare the results with each other. Ideally, all included studies would have used an intraoperative or immediate postoperative image to compare with those obtained later (long-term follow up). However, in this systematic review, only two studies assessed the stability through time.
      • Kim H.J.
      • Bang K.H.
      • Park E.J.
      • et al.
      Evaluation of postoperative stability after open reduction and internal fixation of zygomaticomaxillary complex fractures using cone beam computed tomography analysis.
      • Dakir A.
      • Muthumani T.
      • Prabu N.P.
      • et al.
      One point fixation of zygomatic tripod fractures in the zygomatic buttress through Keen's intraoral approach: a review of 30 cases.
      Another limitation is the heterogeneity among the studies in radiographic assessment, but also in the amount of displacement and comminution of the ZMC fractures. The considerable difference in displacement and comminution between patients from the same study means they could not be stratified in this systematic review. Also, the days from trauma to surgery were not weighed as a success factor. The studies stated that anatomical reduction is best accomplished in the early phase of bone healing. Bone healing and resorption starts three weeks after the trauma, resulting in less interfragmentary support, which means one should aim to operate within 21 days post-injury.
      • Mittal G.
      • Garg R.
      • Sharma S.
      • et al.
      Efficacy of two-point fixation in the management of zygomatic complex fractures - a prospective clinical study.
      • Carr R.M.
      • Mathog R.H.
      Early and delayed repair of orbitozygomatic complex fractures.
      Delayed ZMC fracture repairs are more difficult, challenging and can lead to unsatisfactory reconstructions.
      • Mittal G.
      • Garg R.
      • Sharma S.
      • et al.
      Efficacy of two-point fixation in the management of zygomatic complex fractures - a prospective clinical study.
      Special attention should be paid to two systematic reviews; Gadkari et al (2019) compared malar asymmetry and stability after two-point versus three-point fixation and Jazayeri et al (2019) examined the patients’ outcomes (complication rates and patient-reported satisfaction) of one-point, two-point, three-point, and four-point fixation.
      • Gadkari N.
      • Bawane S.
      • Chopra R.
      • et al.
      Comparative evaluation of 2-point vs 3-point fixation in the treatment of zygomaticomaxillary complex fractures - a systematic review.
      • Jazayeri H.E.
      • Khavanin N.
      • Yu J.W.
      • et al.
      Fixation points in the treatment of traumatic zygomaticomaxillary complex fractures: a systematic review and meta-analysis.
      Unfortunately, both reviews did not define stability further, and also assessed biodegradable material, which is confusing because the material characteristics differ from titanium and can also cause late tissue responses.
      • van Bakelen N.B.
      • Buijs G.J.
      • Jansma J.
      • et al.
      Comparison of biodegradable and titanium fixation systems in maxillofacial surgery: a two-year multi-center randomized controlled trial.
      • Song R.
      • Murphy M.
      • Li C.
      • et al.
      Current development of biodegradable polymeric materials for biomedical applications.
      Biodegradables are, from a mechanical perspective, significantly weaker than titanium,
      • Kim D.H.
      • Kim R.H.
      • Lee J.
      • et al.
      Evaluation of soft tissue asymmetry using cone-beam computed tomography after open reduction and internal fixation of zygomaticomaxillary complex fracture.
      • Buijs G.J.
      • van der Houwen E.B.
      • Stegenga B.
      • et al.
      Mechanical strength and stiffness of biodegradable and titanium osteofixation systems.
      • Gareb B.
      • van Bakelen N.B.
      • Dijkstra P.U.
      • et al.
      Biodegradable versus titanium osteosynthesis in maxillofacial traumatology: a systematic review with meta-analysis and trial sequential analysis.
      which can affect stability. Hence, some caution needs to be exercised regarding the conclusions of both reviews.
      It is, unfortunately, not possible to draw reliable conclusions and to generalise the results about no fixation, one-point fixation, and multiple fixation. Despite the fact that the definitions of stability differ greatly in each study, they support the same principles in terms of outcome measures. The three predictable treatment aspects of ZMC fractures are: adequate anatomical reposition, stability, and to be as least invasive as possible. To comply with these principles, the literature suggests that using a (CB)CT scan operatively has the potential to improve the reposition quality, stability through time, and postoperative complications can be reduced by minimising the number of fixation points.
      • Pons M.
      • Lutz J.C.
      • Chatelain B.
      • et al.
      Impact of intraoperative cone beam computed tomography in the management of zygomatic fractures.
      • Assouline S.L.
      • Meyer C.
      • Weber E.
      • et al.
      How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature.
      Then the debate will shift to the amount of stability required to keep the ZMC in a proper position and how to reach this with a minimal approach. We speculate that new technological developments, such as using 3D technology to produce and insert plates, may achieve this goal, even for comminuted fractures.

      Funding

      No funding was received for this study.

      Conflict of interest

      We have no conflicts of interest.

      Ethics statement/confirmation of patients’ permission

      The study was approved by the internal review board of ACTA (# 2020279). Patients’ consent was not required.

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