Treatment of chronic anterior shoulder dislocation by open reduction and simultaneous Bankart lesion repair

A glenohumeral joint that has remained dislocated for several days is called a chronic dislocation. These old dislocations most often are traumatic but frequently have been produced by a trivial injury as a result of the patient's increasing age and weakness and degeneration of the soft tissue about the shoulder joint such as the subscapularis and other rotator cuff tendons [1, 2]. In younger patients unreduced dislocations often occur in those with alcoholism, seizures, or multiple trauma [3]. Usually the problems and complications of reduction are increased along with the chronicity of dislocation.

Open reduction and joint fixation has been suggested for most unreduced anterior dislocation of shoulder and different fixation methods have been used to prevent redislocation [4–6]. These fixation methods require long time immobilization and cause additional trauma to the articular surface of the humeral head and glenoid [4–6]. Little has been written on the results of these procedures.

Early shoulder motion improves cartilage nutrition and minimizes injury to the articular surfaces [7, 8] but at the same time increases the risk of redislocation.

Given the documented success following Bankart lesion repair in recurrent anterior shoulder dislocation [9], we hypothesized that open reduction and simultaneous Bankart lesion repair of chronic anterior shoulder dislocation has the beneficial effect of safe early motion without the risk of redislocation.

Patients' follow up was between 6 and 18 months with an average of 12 months. No patient was lost to follow up. The final functional results were rated at the time of the last follow up by the system proposed by Rowe and Zarins [10]. This is a point system (total possible point is 100) based on the assessment of pain, motion and function. Final motion was recorded at the end of follow-up period and we reported the loss of ROM by comparison to contra lateral shoulder. In all patients CT scan was performed before and after surgery. Postoperative CT scan was used to determine whether anatomic glenohumeral reduction had been achieved.

The overall Rowe and Zarin's score averaged 86 points. Four out of eight shoulders were graded as excellent, three as good and one as fair. The mean forward flexion and external rotation losses were 18 and 17.5 degrees respectively and the internal rotation loss was three vertebral body levels. Anterior active elevation averaged 140 degrees, external rotation 40 degrees and internal active rotation to the level of the 9^th thoracic body.

All patients were able to do their daily activities with mild or no pain. CT scan showed anterior subluxation in two patients. One of these cases had anterior glenoid bone defect involving one third of the joint surface and fair result in Rowe system. The other subluxated case had subscapularis insufficiency at belly press test and good result at the end of follow-up period (Rowe system). These two patients were able to perform daily activities with mild pain. Mild degenerative changes were present in one patient at final radiographs. Two patients had proximal head migration in their follow-up radiographs. One of them had surgically documented massive rotator cuff tear which was irreparable.

In reviewing the literature there are few studies about the results of operative treatment of chronic anterior shoulder dislocation. Most authors have recommended allograft reconstruction or arthroplasty in large head defects following chronic shoulder dislocation. Gavriilidis stated that shoulder arthroplasty resulted in good midterm results for 12 patients with severe head involvement with benefits for range of motion, pain and patient satisfaction [11]. The average duration of dislocation was 14 months in this report. In 13 patients with locked chronic posterior dislocation of shoulder and defect of between 25-50% of head, Diklic and coworkers reported good results with allograft reconstruction [12]. In our series Hill-Sach's defect was less than 40% and all were non-engaging. We suppose the reason is that the mean duration of dislocation in our cases (10 weeks) was less than that of the mentioned reports.

One fair result in our study was in a case whose shoulder had Subluxation postoperatively. Anterior glenoid bone defect was the reason for subluxation in this patient which shows the necessity of bone grafting or coracoid transfer to the glenoid bone defects in such cases (Figure 2, 3). Perniceni and Augereau described reinforcement of the anterior shoulder complex in three patients after reduction of neglected anterior dislocation of the shoulder [13]. They used the Gosset technique [14] which places a rib graft between the coracoid and the glenoid rim.

Most reports have recommended shoulder joint transfixation to prevent redislocation following open reduction. Neviaser proposed transfixing the shoulder joint with a Swiss screw for three to four weeks [4]. Wilson and Mckeever recommended acromiohumeral crossed transfixing pins to prevent recurrence of the dislocation⁵. Rockwood and Green also suggested using smooth pins through the head into the glenoid for ten to fourteen days [6]. According to our study the results after capsulolabral complex repair appears to be more favorable than previously reported studies which have used metallic fixation methods. Postacchini et al reported good results in all four cases of operatively reduced chronic anterior and posterior dislocation [15]. Goga have reported three excellent, five good and two fair results in ten operatively reduced anterior shoulder dislocation [16]. Acromiohumeral k-wire fixation was used for 4 weeks in that group and the results were evaluated according to Rowe and Zarins system.

Supporting the arm at the side in a safe position was first stated by Rowe and Zarins in 1982 [10]. They recommended simply maintaining the arm at the side anterior to the coronal plane of the body for anterior dislocations and posterior to the coronal plane for posterior dislocations. In a report of seven operatively treated chronic shoulder dislocation with a mean duration of dislocation of 12 weeks, they had no postoperative dislocation using this simple method. Two shoulders were graded as excellent, three as good and two as fair with the mean Rowe score of 78 points.

Capsulolabral complex repair allows early range of motion in a safe range without the fear of redislocation. We began up to 90 degrees of flexion and 0 degree of external rotation immediately in our patients. Although the average duration of dislocation have not pointed in Goga's study and it is difficult to compare his results with the present study, it seems that our patients as the patient in figures 4 & 5 had much better range of motion at the end of follow up period and the average Rowe score in our patients was higher than Goga 's series. It should be mentioned that acromiohumeral fixation method had been used in Goga's study.

Our review of literature revealed just one report similar to our study. Mansat et al reported five patients with old anterior shoulder dislocation with average duration of 14 months [17]. All were treated with open reduction and capsulolabral insertion. At the end of follow up the average Rowe score was 75 points. The duration of dislocation in this group of patients was more than our study and this may be the reason for low Rowe score comparing with our series.

Mild degenerative joint changes were noted in only one patient. Although in the literature there is no report for the true incidence of osteoarthritis after operative reduction of old dislocations, it appears that early osteoarthritis rate is reasonable in our study and we think that the reason may be early motion and not using transfixing implants.

The present study had some important limitations. Although the present study is one of the largest reports in the literature it is confined to only eight patients. Another potential source of uncertainty in this study arises from the duration of follow up period. Longer follow up is needed for the detection of the true incidence of degenerative changes following open reduction of old shoulder dislocations.

In conclusion the authors of this article recommend concomitant open reduction and capsulolabral complex repair, when possible, in the treatment of old anterior shoulder dislocations.

Consent was obtained from the patient for publication of this report and accompanying image.