Arthroscopic Coracoid Bone Block for Posterior Glenohumeral Instability: Description of Surgical Technique and a Case Report.

This case report describes the surgical technique of posterior arthroscopic bone block using the coracoid graft to treat recurrent posterior dislocations and describes preliminary results. Performance of coracoid transfer as a graft for posterior arthroscopic bone block in one patient (two shoulders) with recurrent posterior glenohumeral instability refractory to clinical treatment for six months, excluding volition dislocation. The patient was followed up weekly for the first three weeks when the stitches were removed. Postoperative computed tomography was performed before the patient was authorized to practice contact and aquatic sports (3-4 months after surgery). Patient returned to previous activities without complaints or limitations. There were no neurovascular complications. The initial results using coracoid as a bone graft for posterior instability were positive, and the technique requires reproduction to investigate possible complications. To date, no study has been found in the literature that reports an open or arthroscopic coracoid bone block technique.

Mid-term to long-term results of open posterior bone block grafting in recurrent posterior shoulder instability: a clinical and CT-based analysis.

Background: There is little consensus on the best treatment after failed conservative management of recurrent posterior shoulder instability. The purpose of this study was to analyze our clinical and radiological mid-term to long-term results of an open, posterior bone block procedure for the treatment of recurrent posterior shoulder instability. Methods: From 1999 to 2015, 14 patients were included in the study and available for clinical and radiographic follow-up (FU). FU included a standardized physical examination, assessment of the Constant-Murley-Score, subjective shoulder value, American Shoulder and Elbow Surgeons score, and Western Ontario Shoulder Instability Index. Conventional radiographs and a computed tomography (CT)-scan were performed preoperatively and at latest FU. Glenohumeral arthropathy was classified as per Samilson and Prieto. The CT scans were used to evaluate the structure of the graft (resorption, union), graft positioning, glenoid version, centering of the humeral head, and glenoid erosion and morphology. Results: The median age at the time of surgery was 26 years (range 16-41 years) and the median FU period was 9 years (range 4-20 years). The rate of reported dynamic postoperative subluxation and instability was 46% (n = 6) and the rate of dynamic posterior instability during clinical testing at FU was 31% (n = 4). The tested instability rate in the traumatic group was 14% (n = 1) compared to the atraumatic group with 50% (n = 3) during clinical FU. The mean Constant-Murley-Score increased from preoperatively (77 ± 11 points) to postoperatively (83 ± 14 points, P = .158). The last FU showed an American Shoulder and Elbow Surgeons score of 85 ± 12; the Western Ontario Shoulder Instability Index score was 715 ± 475 points. The mean subjective shoulder value increased from 58% ± 19 preoperatively to 73% ± 17 at final FU (P = .005). Degenerative changes increased by at least one grade in 67% of the patients. Mean preoperative glenoid retroversion (CT) was 7.5° ± 6°. The position of the graft was optimal in 86% (n = 12). In 62% of the cases, a major resorption of the graft (Zhu grade II) was observed. Conclusion: The rate of tested recurrent instability at last FU was as high as 31% (n = 4, atraumatic [n = 3] vs. traumatic [n = 1]) after a median FU of 9 years. Given the moderate improvement of clinical outcome scores, shoulder stability and the increase of degenerative joint changes by at least one grade (Samilson/Prieto) in 67% of patients, a posterior bone block procedure is not a uniformly satisfying treatment option for recurrent posterior shoulder subluxation, especially in cases of atraumatic posterior instability.

Posterior glenoid bone block transfer for posterior shoulder instability: a systematic review.

BACKGROUND: The purpose of this study is to systematically review the literature and evaluate patient-reported outcomes and complication/revision rates of bone block augmentation in the treatment of posterior shoulder instability (PSI). METHODS: PubMed was searched according to PRIMSA guidelines to find clinical studies evaluating patient-reported outcomes, revision, and complication rates in posterior bone block for PSI. A literature search of MEDLINE, EMBASE, and the Cochrane Library was performed based on the PRISMA guidelines. Clinical studies reporting on the complications following posterior bone block were included. RESULTS: Overall, 11 studies (level of evidence [LOE] III: 2, LOE IV: 9) met inclusion criteria, with 225 shoulders. Recurrent instability after the posterior bone block was found to be 9.8%. The overall complication rate was 13.8%, with 0.89% having graft complications, 11.1% having hardware complications, 0.4% having wound complications, 0.4% having nerve complications, and 0.89% having other complications. Residual pain was found in 11.6% of shoulders operated on. Patient-reported outcomes were evaluated most commonly by Rowe (81.4%), Constant (84.6%), and Walch-Duplay scores (81.6%). CONCLUSION: There is a moderate rate of recurrence following posterior bone block for PSI. However, the patient-reported outcomes are high despite there being commonly reported persistent shoulder pain postoperatively.

Risk of neurological injury in posterior bone block surgery for recurrent glenohumeral instability: a cadaveric study.

INTRODUCTION: Recurrent posterior glenohumeral instability poses a challenge for treatment. Bone block procedures have been advocated in cases where a bony defect is present. However, these techniques are not free of complications due to the proximity of neurovascular structures. The aim of this study is to measure the distance to the axillary and suprascapular nerves at the different steps of the procedure. MATERIALS AND METHODS: Ten frozen human cadavers were used. The bone graft was prepared and placed on the posterior aspect of the glenoid, where it was fixed with two K-wires in different positions: parallel to the articular surface and with 20° of medial angulation. The distance from the entry and exit points of the K-wires to the axillary and suprascapular nerves was measured. RESULTS: At the exit point, mean distance from the superior K-wire to the axillary nerve was 4.4 mm in the neutral position and 14.4 mm when medially angulated (p = 0.01) and 2.6 mm and 11.5 mm, respectively, for the inferior K-wire (p < 0.01). No differences were found at the entry point (p = 0.7 and p = 0.3). For the suprascapular nerve, mean distance to the entry point of the superior K-wire was significantly greater when it was inserted with 20° of medial angulation than when placed in neutral position (p = 0.04). No differences were found for the inferior K-wire (p = 0.35). CONCLUSION: Posterior bone block surgery should be performed taking into consideration the possibility of axillary nerve injury anteriorly at the exit point of the K-wires. Wire and screw insertion parallel to the glenoid articular surface may reduce the risk, while increased wire or screw medial angulation with respect to the glenoid surface may heighten risk. LEVEL OF EVIDENCE: Not applicable (cadaveric study).

Painful posterior shoulder instability: Anticipating and preventing failure. A study in 25 patients.

BACKGROUND: Painful posterior shoulder instability (PPSI) is the least common of the three clinical patterns of posterior shoulder instability. PPSI is defined as pain combined with anatomical evidence of posterior instability but no instability events. MATERIAL AND METHOD: We studied a multicentre cohort of 25 patients with PPSI; 23 were identified retrospectively and had a follow-up of at least 2 years and 2 patients were included prospectively. Most patients engaged in sports. RESULTS: All 25 patients underwent surgery, which usually consisted in arthroscopic capsulo-labral reconstruction. The outcome was excellent in 43% of patients; another 43% had improvements but reported persistent pain. The pain remained unchanged or worsened in the remaining 14% of patients. Causes of failure consisted of a missed diagnosis of shoulder osteoarthritis with posterior subluxation, technical errors, and postoperative complications. The main cause of incomplete improvement with persistent pain was presence of cartilage damage. CONCLUSION: Outcomes were excellent in patients who were free of cartilage damage, bony abnormalities associated with posterior instability (reverse Hill-Sachs lesion, erosion or fracture of the posterior glenoid), technical errors, and postoperative complications.

The split portal: Description of a new accessory posterior portal for arthroscopic shoulder instability procedures.

PURPOSE: Open approach to the posterior shoulder during bone block for posterior shoulder instability is challenging. Anatomical study was performed to identify landmarks of a portal, avoiding soft tissue damage, between the infraspinatus (IS) and teres minor (TM) muscles and distant from the supra-scapular nerve (SSN) for arthroscopic shoulder bone block. METHODS: Eight fresh-frozen cadaveric shoulder specimens were used. The arthroscope was introduced through the soft point (SP). A guide wire was placed through the SP, in the rotator interval direction. A posterior open dissection exposed the split between the IS and TM. A new guide wire was placed into the split, parallel to the first wire, to locate the new posterior arthroscopic approach. Ten distances were measured to define the safe position. RESULTS: The mean values were: SP to split IS-TM: 2 ± 0.2 (2-2.8); spinal bone to split IS-TM: 5 ± 0.5 (3-6.2); split IS-TM to posterior glenoid 6 o'clock: 1.3 ± 0.3 (0.6-1.6), 9 o'clock: 1.5 ± 0.3 (1-1.9), and 12 o'clock: 2 ± 0.1 (2.1-2.4); SSN to posterior glenoid 6 o'clock: 2.4 ± 0.2 (2.1-2.6), 9 o'clock: 1.7 ± 0.1 (1.5-1.8), and 12 o'clock: 1.5 ± 0.3 (1.2-2.1); and SSN to split IS-TM: 2 ± 0.3 (1.2-2.1). CONCLUSION: This preliminary anatomical study described a posterior arthroscopic portal located 2 cm under the SP, parallel to the SP portal direction, and finishing between 7 and 8 o'clock at the posterior rim of the glenoid. For arthroscopic shoulder bone block, this portal can avoid muscle and SSN lesions.

Results of an open posterior bone block procedure for recurrent posterior shoulder instability after a short- and long-time follow-up.

PURPOSE: The aim of the present study was to analyse and compare the clinical and radiological results after open posterior bone block procedure at long- (LT) and short-term (ST) follow-up. The hypothesis was that placement of a bone block at the posterior glenoid rim in a technique of extending the glenoid surface will create permanent joint stability even in cases with hyperlaxity without a clinically relevant loss of motion or increase in osteoarthritis. METHODS: Fifteen consecutive shoulders with recurrent posterior dislocation were evaluated clinically and radiologically. The Rowe score, Western Ontario Shoulder Index, Walch-Duplay score and the Constant-Murley score were used for clinical evaluation. The patients were categorized according to their follow-up period as either ST follow-up (min 12 months) or LT follow-up (min 42 months). RESULTS: The clinical results showed no significant difference between ST (9) and LT (6) with good to very good overall results in the subjective as well as the objective scores (CS, RS, WDS). At LT, most patients felt mild to minor pain under strain. The difference in pain between the groups was not significant. Active ranges of motion and strength assessments were normal in all cases. In one case, recurrent dislocations occurred after bone graft resorption 6 months post-operatively. Only one patient presented mild osteoarthritis, without further progress at follow-up. CONCLUSION: The open posterior bone block procedure can be a successful treatment option for recurrent posterior shoulder instability at ST and LT follow-up. This series showed a low rate of recurrent dislocations without development or progression of osteoarthritis. Since soft tissue procedures do not always provide satisfying results, the posterior bone block augmentation presents a reliable technique for the treatment of symptomatic posterior instability. LEVEL OF EVIDENCE: Case Series, Treatment Study, Level IV.

Posterior bone block of chronic locked posterior shoulder dislocations with glenoid augmentation: a retrospective evaluation of ten shoulders.

PURPOSE: The aim of this study, which is the most extensive series to date on this subject, was to present the results of ten shoulders of seven patients treated with the posterior bone block augmentation method with autograft taken from the iliac wing for a chronic locked posterior shoulder dislocation and to evaluate the results in the light of the relevant literature. METHODS: A retrospective examination was made of patients who underwent iliac autograft with glenoid augmentation for chronic posterior shoulder dislocation in our clinic between 2004 and 2011. All of the patients had been initially treated at another centre and referred to our hospital because of continuing or relapsing posterior shoulder dislocation. Assessment was made by physical examination X-ray, computed tomography (CT), and the Constant-Murley score. RESULTS: All the patients were male with a mean age at the time of surgery of 42.4 years (range, 23-53 years), with a mean follow-up period of 40.6 months (range, 24-55 months). On presentation, all the patients had locked posterior shoulder dislocation. Radiological union was evaluated from the CT images taken 24 months postoperatively. The graft was observed to have been incorporated in all cases. The mean postoperative Constant-Murley score was 81.25/100 ± 17.8. In seven of the shoulders, arthropathy findings increased by varying degrees. CONCLUSIONS: A functional and stable shoulder can be obtained with glenoid augmentation in patients with chronic locked posterior shoulder dislocation. When other treatment alternatives are considered for a young patient group, this is a safe and applicable treatment method.

Posterior glenohumeral instability.

The posterior instability of the shoulder is a more difficult diagnostic and therapeutic challenge than the anterior instability. There are many etiologies and causes of posterior instability. Most studies in the literature are retrospective and yield a great variation in therapeutic recommendations. Generally it has to be separated in traumatic and atraumatic instabilities. Most of the traumatic dislocations are impaction fractures of the humeral head against the dorsal glenoid. Therapy is depending on the size of the humeral defect, the duration of dislocation and the functional demand of the patient. Therapeutic possibilities are closed reduction and fixation with a cast, open reduction and the transfer of the lower tubercule (McLaughlin's procedure), lifting of the defect and supporting with cancellous bone, subcapital rotational osteotomy or arthroplasty. The therapy of choice for atraumatic instability is a individualized rehabilitation program with strengthening and balancing of rotatator cuff muscles and scapular stabilizers. Psychologic abnormalities and emotional problems have to be recognized prior to any operative procedure. These patients are no operative candidates. Operative treatment of choice is the posterior capsular shift adressing the causative redundancy or laxity of the postero-inferior capsule. Posterior bony procedures as glenoid osteotomy or bone block transfers are indicated, if the pathologic geometry of the glenoid is primarily responsible for posterior instability. It is strongly recommended to combine them with a capsular shift to adress the secondary capsular redundancy.