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Clinical and Anatomical Outcomes of Isolated Coracoclavicular Fixation after Acromioclavicular Joint Injury: Is It Stable Enough or Is An Additional Horizontal Fixation Necessary?

Open AccessPublished:October 29, 2022DOI:https://doi.org/10.1016/j.jseint.2022.10.001

      Abstract

      Background

      Recently, an emphasis has been put on anatomical reduction of acromioclavicular joint both in vertical and hortizontal planes for management of acromioclavicular joint injuries due to persisting horizontal instability. Therefore an additional acromioclavicular fixation in horizontal plane has been recommended. However, relation between horizontal acromioclavicular joint instability and clinical outcomes is still controversial. This study aims to evaluate outcomes of isolated coraco-clavicular fixation using arthroscopic assisted single coraco-clavicular tunnel technique in grade III and V acromioclavicular joint injuries and to investigate the correlation between anatomical and clinical outcomes.

      Methods

      This study was conducted with 19 patients with grade III or V acromioclavicular joint injury. Clinical outcomes included postoperative pain intensity and functional outcomes (Constant score, ASES and SSV). Radiological evaluations were performed using radiographs and postoperative computed tomography scans. Degree of initial injury and postoperative stability both on axial and coronal planes were evaluated after radiological assessment. Correlations between anatomical and clinical outcomes were investigated using Pearson’s correlation test.

      Results

      At final follow-up assessment, mean pain score was 1.8±1.8, mean ASES score was 81.0±15.4, mean SSV was 81.3±19.6 and mean Constant score was 86.3±14.8. Mean loosening ratio and AC distance were 43.5±30.6% and 4.3±12.4mm respectively. No correlation was observed between postoperative anatomical and clinical outcomes (p>0.05).

      Conclusion

      Additional acromioclavicular fixation on horizontal plane is not a prerequisite for all injuries, there is no significant association between horizontal instability and clinical outcomes and indications of an additional acromioclavicular fixation needs to determined.

      Keywords

      The acromioclavicular (AC) joint plays a crucial role to establish anatomical relation between axial skeleton and upper extremity and is an important component of shoulder girdle. AC joint injuries are common with an overall incidence rate of 9.2 per 1000 person-years in young athletes
      • Pallis M.
      • Cameron K.L.
      • Svoboda S.J.
      • Owens B.D.
      Epidemiology of acromioclavicular joint injury in young athletes.
      and comprise approximately 12% among all shoulder injuries
      • Braun S.
      • Imhoff A.B.
      • Martetschlaeger F.
      Primary fixation of acromioclavicular joint disruption.
      ,
      • Li X.
      • Ma R.
      • Bedi A.
      • Dines D.M.
      • Altchek D.W.
      • Dines J.S.
      Management of acromioclavicular joint injuries.
      ,
      • Martetschläger F.
      • Tauber M.
      • Habermeyer P.
      • Hawi N.
      Arthroscopically assisted acromioclavicular and coracoclavicular ligament reconstruction for chronic acromioclavicular joint instability.
      . These injuries may cause chronic pain and disability especially in athletes and young population. Both coracoclavicular (CC) and AC ligaments make contribution to AC joint stability in conjunction with joint capsule
      • Dyrna F.G.E.
      • Imhoff F.B.
      • Voss A.
      • Braun S.
      • Obopilwe E.
      • Apostolakos J.M.
      • et al.
      The integrity of the acromioclavicular capsule ensures physiological centering of the acromioclavicular joint under rotational loading.
      . Previous biomechanical studies have shown that vertical stability of the joint is mainly ensured by CC ligaments while AC ligaments are relatively more important regarding maintanence of horizontal stability
      • Fukuda K.
      • Craig E.V.
      • An K.N.
      • Cofield R.H.
      • Chao E.Y.
      Biomechanical study of the ligamentous system of the acromioclavicular joint.
      .
      Management of AC joint injuries is among the most controversial topics in shoulder surgery and treatment is most commonly determined according to six-grade classification described by Rockwood. Although consensus seems to be present in favor of surgical treatment for grades IV to VI and conservative management for grades I to II; management of type III injuries still constitutes a major controversy
      • Lädermann A.
      • Grosclaude M.
      • Lübbeke A.
      • Christofilopoulos P.
      • Stern R.
      • Rod T.
      • et al.
      Acromioclavicular and coracoclavicular cerclage reconstruction for acute acromioclavicular joint dislocations.
      ,
      • Mazzocca A.D.
      • Arciero R.A.
      • Bicos J.
      Evaluation and treatment of acromioclavicular joint injuries.
      ,
      • Rios C.G.
      • Mazzocca A.D.
      Acromioclavicular joint problems in athletes and new methods of management.
      . Therefore; an update has been suggested for Rockwood classification by the ISAKOS Upper Extremity Committee regarding grade III injuries, in order to enhance the knowledge on and clinical approach to these “gray zone” injuries
      • Beitzel K.
      • Mazzocca A.D.
      • Bak K.
      • Itoi E.
      • Kibler W.B.
      • Mirzayan R.
      • et al.
      ISAKOS upper extremity committee consensus statement on the need for diversification of the Rockwood classification for acromioclavicular joint injuries.
      . Multiple surgical techniques have been described for management of AC joint injuries but none have been demonstrated to be superior to others with respect to clinical outcomes
      • Lizaur A.
      • Sanz-Reig J.
      • Gonzalez-Parreño S.
      Long-term results of the surgical treatment of type III acromioclavicular dislocations: an update of a previous report.
      ,
      • Mazzocca A.D.
      • Arciero R.A.
      • Bicos J.
      Evaluation and treatment of acromioclavicular joint injuries.
      . Intraoperative determination of horizontal stability is difficult in arthroscopic single plane CC fixation procedures and localization of coracoid fixation can influence reduction in horizontal plane. Therefore, an emphasis has been recently put on restoration of not only vertical but also horizontal stability as previous biomechanical studies have reported that isolated CC stabilization does not provide sufficient horizontal stability
      • Beitzel K.
      • Obopilwe E.
      • Apostolakos J.
      • Cote M.P.
      • Russell R.P.
      • Charette R.
      • et al.
      Rotational and translational stability of different methods for direct acromioclavicular ligament repair in anatomic acromioclavicular joint reconstruction.
      ,
      • Saier T.
      • Venjakob A.J.
      • Minzlaff P.
      • Föhr P.
      • Lindell F.
      • Imhoff A.B.
      • et al.
      Value of additional acromioclavicular cerclage for horizontal stability in complete acromioclavicular separation: a biomechanical study. Knee Surgery, Sport.
      .
      However, there is still controversy with respect to relation between horizontal AC joint instability and clinical outcomes
      • Blazar P.E.
      • Iannotti J.P.
      • Williams G.R.
      Anteroposterior instability of the distal clavicle after distal clavicle resection.
      ,
      • Jordan R.W.
      • Malik S.
      • Bentick K.
      • Saithna A.
      Acromioclavicular joint augmentation at the time of coracoclavicular ligament reconstruction fails to improve functional outcomes despite significantly improved horizontal stability.
      ,
      • Minkus M.
      • Hann C.
      • Scheibel M.
      • Kraus N.
      Quantification of dynamic posterior translation in modified bilateral Alexander views and correlation with clinical and radiological parameters in patients with acute acromioclavicular joint instability.
      . The purpose of this study is to evaluate clinical and radiological outcomes of AC joint injuries treated with arthroscopic assisted single coraco-clavicular tunnel (SCT) technique and to investigate the relation between anatomical and clinical outcomes.

      2. Materials and methods

      This retrospective review was conducted at two different university hospitals which are tertiary referral centers for shoulder disorders and trauma. Institutional review board approval (E-45446446-010.99-17064) was obtained from relevant board. All included patients received informed consent at final follow-up control. Patients who underwent AC joint fixation using arthroscopic assisted SCT technique between January 2017 and February 2020 were included to study. Inclusion criteria were acute (within 6 weeks of the injury) and type III or V AC joint injury according to Rockwood classification . Exclusion criteria were; (1) age < 18 years, (2) age > 65 years, (3) presence of a fracture, (4) type III injuries which were treated conservatively (sedantery patients who did not have scapular dyskinesia), (5) presence of concomitant lesions (cuff tear or labral injury), (6) presence of apparent glenohumeral or AC joint arthritis seen on preoperative radiographs and (7) history of any rheumatic condition. Type IV injuries were also excluded as they were treated using a fixation on horizontal plane with open surgery.
      All procedures were performed by two senior authors under general anaesthesia and patients positioned in beach chair position. After establishing a standard posterior portal, a diagnostic arthroscopy was carried out for any concomittant intra-articular pathology. Then anterior portal was established and coracoid base was identified by following subscapularis tendon medially. Soft tissue covering the coracoid base was débrided using radiofrequency. A small longitudinal incision originating from about 3-4 cm medial to AC joint was made and drill guide was positioned under coracoid. A guide wire was drilled using drill guide under fluoroscopic vision through clavicle and coracoid. Then holes were drilled over the guide wire through the clavicle and coracoid. A nitinol wire was passed through opened holes for shuttling the Twinbridge endobutton (Smith & Nephew, Memphis, TN, USA) to settle under the coracoid base. The AC joint reduction was carried out by the aid of an assistant and checked fluoroscopically. Once the inferior button was seated against the coracoid, the superior button was positioned onto the sutures exiting the hole on the clavicle and the sutures were tied. Final reduction was assessed under fluoroscopic view.
      Immobilization with a simple sling was followed for all patients for a duration of 4 weeks. Active elbow and wrist motion was allowed immediately after surgery. Active range of motion and strengthening exercises were initiated gradually starting from the 6th week postoperatively respecting the pain-free range of motion limits. Full daily physical activity was allowed 3 months and return to sports was allowed 6 months after surgery according to recovery of each individual.
      Clinical follow-up of each patient was regularly performed at postoperative 2 weeks, 6 weeks, 3 months, 6 months, 12 months and each following year. All patients who underwent arthroscopic assisted AC fixation with SCT technique during study period were assessed for eligibility. Patients who met inclusion criteria were contacted and an appointment was made for final clinical and radiological assessment. The clinical evaluations included assessment of postoperative pain intensity using a visual analogue scale (VAS); assessment of objective shoulder function using Constant shoulder score
      • Constant C.R.
      • Murley A.H.
      A clinical method of functional assessment of the shoulder.
      and assessment of subjective shoulder function using ASES (American Shoulder and Elbow Surgeons) shoulder score
      • Richards R.R.
      • An K.-N.
      • Bigliani L.U.
      • Friedman R.J.
      • Gartsman G.M.
      • Gristina A.G.
      • et al.
      A standardized method for the assessment of shoulder function.
      and the Subjective Shoulder Value (SSV) score
      • Gilbart M.K.
      • Gerber C.
      Comparison of the subjective shoulder value and the Constant score.
      . All clinical assessments were performed by a single independent reviewer.
      All patients had preoperative and early postoperative (1st day postoperatively) standard comparative anteroposterior (AP) radiograph of acromioclavicular girdle. At final follow-up evaluation, late postoperative comparative AP shoulder radiographs and computed tomography (CT) scans of the affected shoulder were obtained. All radiographs were obtained by a single radiology technician following a standardized protocol. Comparitve AP radiographs of bilateral AC joints were obtained with patients in erect position and midcoronal plane of the patient parallel to the image receptor in a manner to place the AC joint at the center of image receptor with affected arm in a neutral position by the patient’s side. Beam angle was 10° cephaled relative to horizontal plane pointing the center of AC joint. The coracoclavicular (CC) distance was measured as the distance between the tip of the dorsal surface of the coracoid and opposing undersurface of the clavicle on preoperative, early postoperative and late postoperative AP radiographs. Implant loosening and loss of vertical stability during follow-up period was determined as loosening ratio (percentage) (Figure 1). Horizontal stability was evaluated on postoperative axial CT images and interpreted as acromioclavicular (AC) distance which was measured as the distance between the most anterior point of the lateral clavicular end and the acromion (Figure 2). Posterior clavicular displacement was remarked with negative values. AC distance higher than 10mm was considered as major horizontal instability. All radiological measurements were performed using a software (RadiAnt DICOM Viewer Version 5.5.0, Medixant, Poznan, Poland)
      Figure thumbnail gr1
      Figure 1(a) Early postoperative and (b) late postoperative anteroposterior shoulder radiographs of a patient. A and B indicates coracoclavicular (CC) distances measured on these radiographs. Loosening ratio was calculated according to these values
      Figure thumbnail gr2
      Figure 2Axial computed tomography scan of a patient. A indicates the most anterior part of the acromion and B indicates the most anterior part of the lateral end of the clacivle. C is the acromioclavicular (AC) distance, which is the distance between points A and B and is used to determine the horizontal stability of AC joint.

      2.1 Statistical analysis

      All statistical analyses were performed using GraphPad Prism Software for Windows (Version 8.0.1, San Diego, California, USA). Mean, median, range, standard deviation and percentage were used as descriptive statistical methods to analyze the study data. The correlations between anatomical outcomes (preoperative, early postoperative, late postoperative CC distance, loosening percentage and postoperative AC distance) and clinical outcomes (Constant score, ASES score, SSV score and pain score) were statistically evaluated using Pearson’s correlation test. Statistical significance level was set at p=0.05 for all analyses.

      3. Results

      24 patients underwent arthroscopic assisted AC joint fixation with SCT technique during study period, of which 19 patients who met the inclusion criteria were included to study. Four patients were excluded and one patient did not show up to final follow-up appointment. Included patients consisted of 16 males and 3 females (84.2% and 15.8%). Mean age of patients was 35.1±9.8 years, mean follow-up duration was 30.2±3.1 months and mean body-mass index (BMI) was 25.8±3.2 kg/m2. There were 10 right shoulders and 9 left shoulders. Mechanism of injury was car accident in 2 patients (10.5%), sports injury in 12 patients (63.1%) and fall from a standing height in 5 patients (26.3%). There was no professional overhead athlete among included patients. There were 3 football players, 1 hiker and 2 runners who used to participate in these sportive activities for recrational purposes. Mean time from injury until surgery was 6.8±5.2 days. Only in two patients surgery time exceeded two weeks (17 and 18 days after injury).
      According to Rockwood classification, there were 10 (52.6%) type III injuries and 9 (47.6%) type V injuries (Table I). On preoperative radiographs, mean CC distance was 19.6±4.7mm. Assessment of early postoperative radiograps which were obtained 1st day after surgery revealed that mean early postoperative CC was 6.5±2.6 mm. On radiographs which were obtained at final follow-up control, mean late postoperative CC distance was 9.8±2.9mm. Implant loosening was assessed comparing early and late postoperative CC distances and interpreted as loosening ratio. In overall population, mean loosening ratio was 76.3±118 %. However; in two patients (10.5%) (patient 5 and 16), loosening ratio was higher than 100% (Table I). These patients were considered as fixation failures rather than implant loosening and mean loosening ratio was 43.5±30.6 % excluding these two patients. Assessment of postoperative CT scan images showed that mean AC distance was 4.3±12.4 mm. While no horizontal instability occured in four patients (21.1%) (AC distance = 0mm), five patients (26.3%) had posterior clavicular displacement and 10 patients (52.6%) had anterior clavicular displacement. Among patients who had horizontal clavicular displacement, two patients had major horizontal instability (AC distance > 10mm) (one in posterior and one in anterior direction) (Table I).
      Table IRadiological and clinical outcomes of patients. (AC: acromioclavicular) (*: Loosening ratio >100% considered as repair failure)
      Patient numberInjury TypeLoosening percentage (%)AC distance (mm)VASConstantASESSSV
      1III5.17.356858.370
      2V04.255854.940
      3V72.5-5.6010095.0100
      4III80.8046251.650
      5III177.8*7.009693.390
      6V85.1-4.438564.960
      7III27.4019693.3100
      8III0009291.6100
      9V63.55.809078.385
      10III79.1-5.6010095.0100
      11V80.013.629480.090
      12III13.68.009893.395
      13III41.19.629290.080
      14V9.35.838374.975
      15III51.2-5.2010095.0100
      16V531.3*038578.370
      17V28.85.828586.790
      18V54.4-12.245564.950
      19III48.34.80100100100
      At final follow-up assessment, mean pain score was 1.8±1.8 and 12 patients (63.2%) had no or minimal pain (VAS score, 0-2). Satisfactory subjective functional outcomes were observed with mean ASES score was 81.0±15.4 and SSV was 81.3±19.6. Mean Constant score was 86.3±4.8 and 14 patients (73.7%) showed good objective functional outcome (Constant score ≥ 85/100).
      Severity of initial AC joint injury as assessed according to preoperative CC distance correlated with subjective functional outcomes (ASES score and SSV) (p=0.035 and 0.026 respectively) but not with either pain (VAS) outcomes (p=0.168) or objective functional outcomes (Constant Score) (p=0.104) (Figure 3). No association was observed between postoperative CC distance and clinical outcomes (p=0.991; 0.786; 0.472 and 0.262 respectively for pain score, Constant score, ASES score and SSV) (Figure 4). Similarly, other anatomical outcomes (degree of implant loosening and horizontal stability) did not correlated with either pain or functional outcomes (p=0.854; 0.786; 0.952; 0.688 for loosening ratio and 0.981; 0.489; 0.836; 0.578 for AC distance respectively) (Figure 5 and 6).
      Figure thumbnail gr3
      Figure 3Correlation graphs illustrating relationship between preoperative coracoclavicular (CC) distance and clinical outcomes.
      Figure thumbnail gr4
      Figure 4Corralation graphs illustrating relationship between late postoperative coracoclavicular (CC) distance and clinical outcomes
      Figure thumbnail gr5
      Figure 5Correlation graphs illustrating relationship between loosening ratio and clinical outcomes
      Figure thumbnail gr6
      Figure 6Correlation graphs illustrating relationship between acromioclavicular (AC) distance and clinical outcomes. Negative values for AC distance reflects posterior horizontal instability.
      During follow-up period, one patient developed postoperative frozen shoulder that did not respond well to aggressive rehabilitation. Manipulation under general anaesthesia and arthroscopic capsular release was performed and agreeable shoulder range of motion was achieved at final follow-up assessment. Mild acromioclavicular joint arthritis was present on postoperative radiographs of two patients (patients 13 and 14) without apparent deterioration of clinical outcomes. Severe heterotopic ossification was observed on postoperative images of one patient (Patient 5) which was located on trajectory of the tunnel (Figure 7). Despite the presence of heterotopic ossification and fixation failure, this patient had considerable satisfactory clinical outcomes.
      Figure thumbnail gr7
      Figure 7(a) Coronal and (b) sagittal computed tomography scan images of a patient showing apparent heterotopic ossification located around the tunnel.

      4. Discussion

      The most important finding of the present study was that arthroscopic assisted SCT technique showed good clinical outcomes notwithstanding persistent vertical or horizontal instability and that there was no correlation between clinical and anatomical outcomes. Unlike recent reports suggesting addition of an AC fixation in order to establish stability both in horizontal and coronal planes
      • Aliberti G.M.
      • Kraeutler M.J.
      • Trojan J.D.
      • Mulcahey M.K.
      Horizontal instability of the acromioclavicular joint: a systematic review.
      ,
      • Barth J.
      • Duparc F.
      • Andrieu K.
      • Duport M.
      • Toussaint B.
      • Bertiaux S.
      • et al.
      Is coracoclavicular stabilisation alone sufficient for the endoscopic treatment of severe acromioclavicular joint dislocation (Rockwood types III, IV, and V)?.
      ; results of this study showed that isolated CC fixation provides sufficient stability and agreeable clinical outcomes for most of the cases and that indications for an additional AC fixation need to be clarified.
      Current knowledge lacks evident data and there are published reports indicating conflicting results about contribution of an additional AC fixation to biomechanical and clinical outcomes. A recent biomechanical study showed that addition of a stabilizing suture across AC joint to either single or double clavicular tunnel CC reconstruction did not result with significant improvement in horizontal stability and all constructs had inferior horizontal stability compared to native joint. Results of this study implied the importance of an intact AC joint capsule and deltotrapezial fascia to maintain horizontal stability
      • Hislop P.
      • Sakata K.
      • Ackland D.C.
      • Gotmaker R.
      • Evans M.C.
      Acromioclavicular joint stabilization: a biomechanical study of bidirectional stability and strength.
      . Another biomechanical study by Theopold et al showed that addition of an AC cerclage had negligible effect to horizontal stability in the presence of a double coracoclavicular reconstruction
      • Theopold J.
      • Schöbel T.
      • Fischer J.-P.
      • Löffler S.
      • Osterhoff G.
      • Schleifenbaum S.
      • et al.
      Acromioclavicular joint reconstruction: an additional acromioclavicular cerclage does not improve horizontal stability in double coraco-clavicular tunnel technique. Knee Surgery, Sport.
      . In contrast to these reports, several biomechanical studies reported significant improvement in horizontal stability with additional AC augmentation compared to isolated CC ligament reconstruction
      • Gonzalez-Lomas G.
      • Javidan P.
      • Lin T.
      • Adamson G.J.
      • Limpisvasti O.
      • Lee T.Q.
      Intramedullary acromioclavicular ligament reconstruction strengthens isolated coracoclavicular ligament reconstruction in acromioclavicular dislocations.
      ,
      • Saier T.
      • Venjakob A.J.
      • Minzlaff P.
      • Föhr P.
      • Lindell F.
      • Imhoff A.B.
      • et al.
      Value of additional acromioclavicular cerclage for horizontal stability in complete acromioclavicular separation: a biomechanical study. Knee Surgery, Sport.
      .
      Recent clinical data is mostly in favor of anatomical restoration of AC joint in bidirectional planes with additional AC stabilization in order to obtain better clinical results. A systematic review by Aliberti et al suggested better clinical results with incorporation of AC ligament reconstruction to current CC fixation procedures due to restoration of horizontal stability
      • Aliberti G.M.
      • Kraeutler M.J.
      • Trojan J.D.
      • Mulcahey M.K.
      Horizontal instability of the acromioclavicular joint: a systematic review.
      . In contrast to findings of the present study; Barth et al showed that anatomical outcome significantly correlates with functional outcome and accurate reduction is a prerequisite for better results. Authors suggested that isolated CC stabilization is not sufficient to provide lasting stability and recommended that AC joint should be approached routinely in addition to CC fixation
      • Barth J.
      • Duparc F.
      • Andrieu K.
      • Duport M.
      • Toussaint B.
      • Bertiaux S.
      • et al.
      Is coracoclavicular stabilisation alone sufficient for the endoscopic treatment of severe acromioclavicular joint dislocation (Rockwood types III, IV, and V)?.
      . However, literature still lacks evident data to draw such assertive conclusion and clear indications of additional AC stabilization should be determined. In accordance with the present study, Schiebel et al reported good to excellent results in acute high-grade AC joint injuries treated with double coracoclavicular tunnel technique despite persistent vertical or horizontal instability in some cases
      • Scheibel M.
      • Dröschel S.
      • Gerhardt C.
      • Kraus N.
      Arthroscopically assisted stabilization of acute high-grade acromioclavicular joint separations.
      . A recent systematic review accordingly demonstrated that additional AC augmentation does not improve functional outcomes despite better restoration of horizontal stability biomechanically. Moreover, no difference in complication or revision rates was found between isolated CC ligament reconstruction and cases with additional AC augmentation
      • Jordan R.W.
      • Malik S.
      • Bentick K.
      • Saithna A.
      Acromioclavicular joint augmentation at the time of coracoclavicular ligament reconstruction fails to improve functional outcomes despite significantly improved horizontal stability.
      .
      Eventhough an additional AC stabilization would provide a better horizontal stability, its contribution to clinical outcomes is questionable since the findings of this study showed that isolated CC fixation seems to be sufficient to provide satisfactory clinical outcomes despite persisting instability and that no correlation was present between clinical and anatomical outcomes. In severe AC joint injuries, owing to disruptions of the AC ligaments, CC ligament and deltotrapezial fascia; both static and dynamic stability of AC joint is impaired thus leading to an unstable AC joint. Recent literature suggests that reconstruction of each stabilizing component of AC joint, both CC and AC ligaments, should be adressed in order to obtain an accurate reduction of the joint which is essential to obtain good functional outcomes. Besides that, an AC fixation may reduce the stress on the CC fixation implant and prevent a possible implant loosening and fixation failure in long term for these severe cases. Our findings showed that these recommendations are neglibile for most patients; however, we still believe that they may be valid for some confined patient population where even small differences of clinical outcome may be of vital importance like in elite athletes. Therefore, we think that determination of clear indications of an additional AC stabilization is essential to guide clinical practice and further research with higher evidence is necessary on this topic.
      Retrospective nature of the study constitutes first limitation to our study. Second, absence of a control group treated with an additional AC stabilization limits the effect of the study. Small patient number is another limitation but we think that compared to previously published series; this study has a considerable patient size. Short to mid-term results are presented in this study which also constitutes a limitation. Another limitation is classification of AC joint injuriy severity with Rockwood classification whose reliability and reproducibility has been challenged
      • Cho C.-H.
      • Hwang I.
      • Seo J.-S.
      • Choi C.-H.
      • Ko S.-H.
      • Park H Bin
      • et al.
      Reliability of the classification and treatment of dislocations of the acromioclavicular joint.
      . The study population of current study was mostly constituted of sedantary individuals which may also be another limitation since reported results may not apply for professional athletes.

      Conclusion

      Arthroscopic assissted SCT tecnique is a favorable surgical option for treatment of AC joint injuries with good clinical outcomes. Clinical outcome and patient satisfaction is not correlated with structural outcome and good results can be achieved despite persistent horizontal instability. Therefore, additional AC fixation on horizontal plane is not a prerequisite for all AC joint injuries. Further research are needed to clarify indications for a horizontal plan fixation of AC joint.

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