Revision posterior shoulder stabilization

Current Concepts in Assessment and Management of Failed Posterior Labral Repair

Recurrent posterior shoulder instability after primary repair is uncommon, but presents a challenging clinical scenario. Most revisions in failed labral repair were associated with glenoid bone morphology related to critical bone loss, retroversion, or dysplasia. A variety of treatment options exist which include revision labral repair with or without capsular plication, glenoid osteotomy, humeral rotational osteotomy, or glenoid bone augmentation. No single technique has been shown to be superior and each technique has strengths and limitations. Therefore, thoughtful evaluation and planning is critical to address each patient's individual pathology to maximize success after revision surgery.

Biomechanical Evaluation of Posterior Shoulder Instability With a Clinically Relevant Posterior Glenoid Bone Loss Model

BACKGROUND

Existing biomechanical studies of posterior glenoid bone loss and labral pathology are limited by their use of anterior instability models, which differ in both orientation and morphology and have been performed in only a single, neutral arm position.

PURPOSE

To evaluate the biomechanical effectiveness of a posterior labral repair in the setting of a clinically relevant posterior bone loss model in various at-risk arm positions.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten fresh-frozen cadaveric shoulders were tested in 7 consecutive states using a 6 degrees of freedom robotic arm: (1) native, (2) posterior labral tear (6-9 o'clock), (3) posterior labral repair, (4) mean posterior glenoid bone loss (7%) with labral tear, (5) mean posterior glenoid bone loss with labral repair, (6) large posterior glenoid bone loss (28%) with labral tear, and (7) large posterior glenoid bone loss with labral repair. Bone loss was created using 3-dimensional printed computed tomography model templates. Biomechanical testing consisted of 75 N of posterior-inferior force and 75 N of compression at 60° and 90° of flexion and scaption. Posterior-inferior translation, lateral translation, and peak dislocation force were measured for each condition.

RESULTS

Labral repair significantly increased dislocation force independent of bone loss state between 10.1 and 14.8 N depending on arm position. Dislocation force significantly decreased between no bone loss and small bone loss (11.9-13.5 N), small bone loss and large bone loss (9.4-14.3 N), and no bone loss and large bone loss (21.2-26.5 N). Labral repair significantly decreased posterior-inferior translation compared with labral tear states by a range of 1.0 to 2.3 mm. In the native state, the shoulder was most unstable in 60° of scaption, with 29.9 ± 6.1-mm posterior-inferior translation.

CONCLUSION

Posterior labral repair improved stability of the glenohumeral joint, and even in smaller to medium amounts of posterior glenoid bone loss the glenohumeral stability was maintained with labral repair in this cadaveric model. However, a labral repair with large bone loss could not improve stability to the native state.

CLINICAL RELEVANCE

This study shows that larger amounts of posterior glenoid bone loss (>25%) may require bony augmentation for adequate stability.

Outcomes of Revision Arthroscopic Posterior Labral Repair and Capsulorrhaphy: A Systematic Review

Background

Failure rates up to 14% have been reported after arthroscopic posterior capsulolabral repair. It is unknown if revision arthroscopic posterior capsulolabral stabilization has inferior restoration of stability and return to sport when compared with primary repair. Optimal management of failed posterior capsulolabral stabilization is unknown.

Purpose

To report outcomes of revision posterior capsulolabral repair and factors that contribute to failure and to determine optimal management of failed posterior stabilization procedures.

Study Design

Systematic review; Level of evidence, 4.

Methods

A computerized search of the PubMed, EMBASE, and Web of Science databases and manual screening of selected article reference lists were performed in January 2022. Randomized controlled trial, cohort, case-control, and case series studies reporting clinical outcomes of revision arthroscopic posterior capsulolabral repair were eligible. Patient characteristics, indications for revision, intraoperative findings, surgical techniques, and patient-reported outcomes were recorded. Owing to heterogeneity of reported outcomes, data were summarized and presented without pooled statistics.

Results

Only 3 of the 990 identified studies met inclusion criteria. The included studies encompassed 26 revision arthroscopic posterior capsulolabral repairs, with follow-up ranging from 2.3 to 5.3 years. The failed index procedure was arthroscopic capsulolabral repair with suture anchors (n = 22) or posterior thermal capsulorrhaphy (n = 4). The primary indications for revision were recurrent instability and pain. Six patients experienced recurrent instability after revision. Patient satisfaction ranged from 15% to 25%.

Conclusion

This systematic review of 3 studies demonstrated that the incidence of persistent pain and recurrent instability after revision arthroscopic posterior shoulder stabilization is common, and despite slight improvement in patient-reported outcomes, many patients are dissatisfied with their clinical outcomes. Revision arthroscopic posterior shoulder stabilization appears to have a significant failure rate, and there is need for additional prospective studies to help determine the best intervention for these patients.

Anterior and posterior glenoid bone augmentation options for shoulder instability: state of the art

Bony lesions are highly prevalent in anterior shoulder instability and can be a significant cause of failure of stabilisation procedures if they are not adequately addressed. The glenoid track concept describes the dynamic interaction between the humeral head and glenoid defects in anterior shoulder instability. It has been beneficial for understanding the role played by bone defects in this entity. As a consequence, the popularity of glenoid augmentation procedures aimed to treat anterior glenoid bone defects; reconstructing the anatomy of the glenohumeral joint has risen sharply in the last decade. Although bone defects are less common in posterior instability, posterior bone block procedures can be indicated to treat not only posterior bony lesions, attritional posterior glenoid erosion or dysplasia but also normal or retroverted glenoids to provide an extended glenoid surface to increase the glenohumeral stability. The purpose of this review was to analyse the rationale, current indications and results of surgical techniques aimed to augment the glenoid surface in patients diagnosed of either anterior or posterior instability by assessing a thorough review of modern literature. Classical techniques such as Latarjet or free bone block procedures have proven to be effective in augmenting the glenoid surface and consequently achieving adequate shoulder stability with good clinical outcomes and early return to athletic activity. Innovations in surgical techniques have permitted to perform these procedures arthroscopically. Arthroscopy provides the theoretical advantages of lower morbidity and faster recovery, as well as the identification and treatment of concomitant pathologies.

Risk Factors for Revision Posterior Shoulder Stabilization in Throwing Athletes

Background

Revision posterior shoulder capsulolabral repair has inferior outcomes compared with primary surgery. Risk factors for revision in throwing athletes are unknown.

Purpose/Hypothesis

The purpose of this study was to characterize the revision rate and risk factors for revision surgery in throwing athletes. It was hypothesized that female athletes and those with smaller glenoid bone width would be at higher risk for revision surgery.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 105 throwing athletes who underwent arthroscopic posterior capsulolabral repair of their throwing shoulder were reviewed at a minimum of 2-year follow-up, and patients who required a revision were compared with those who did not. Collected data compared between the revision and no-revision groups included age, sex, contact sport participation, and return to sport (RTS). American Shoulder and Elbow Surgeons (ASES) score, Kerlan-Jobe Orthopaedic Clinic (KJOC) score, stability, pain, strength, range of motion (ROM), and patient satisfaction. Radiographic parameters including glenoid bone version, cartilage version, labral version, bone width, labral width, glenoid labral version and width weight were also compared between both groups.

Results

Nine throwers required revision (8.6%) at an average of 2.8 years postoperatively. There were more female athletes in the revision than no-revision group (55.5% vs 23.4%; P = .03). There was no significant difference in age, proportion of contact athletes, rotator cuff tears, glenoid bone version, cartilage version, labral version, labral version weight, bone width, labral width, or labral width weight. Both groups had similar preoperative, postoperative, and change in ASES, KJOC, pain, strength, stability, and ROM scores. The proportion of patients with full strength and with full ROM, as well as patients who were satisfied with outcomes was similar between groups. Fewer patients in the revision group returned to sports compared with those in the no-revision group (14.3% vs 83.6%; P < .001), although return to sports at same level was not significantly different between groups (14.3% vs 37.2%; P = .41).

Conclusion

The revision rate of arthroscopic posterior shoulder stabilization in throwers was 8.6%. Female athletes were at higher risk for revision, and return to sports was lower in patients who underwent revision surgery.

Patient Positioning in Arthroscopic Management of Posterior-Inferior Shoulder Instability: A Systematic Review Comparing Beach Chair and Lateral Decubitus Approaches

PURPOSE

To analyze the available literature pertaining to clinical outcomes and complications of posterior-inferior shoulder stabilization performed arthroscopically in either the beach chair (BC) or lateral decubitus (LD) position.

METHODS

According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), 3 databases (PubMed, EMBASE, and Medline) were searched up to January 2018 for English-language studies on posterior shoulder instability. Descriptive statistics are presented. The Methodological Index for Non-Randomized Studies (MINORS) scale was used to assess quality.

RESULTS

Twenty-five studies were included, examining 1,085 patients (n = 140 BC; n = 945 LD), of mean age 25.0 years, 27.1% female, and mean 3.1 years of follow-up. MINORS scores for BC and LD were 11.2 and 9.8, respectively. Regardless of positioning, patients did not differ across numerous outcomes and various surgical factors (e.g., number of portals, anchors, anchor types, concomitant pathology, or postoperative rehabilitation protocol). Postoperative patient satisfaction ranged from 85% to 87.5% and 93% to 100% for patients treated in BC and LD positions, respectively. Although not reported for BC, overall and preinjury return-to-play (RTP) rates in LD patients ranged from 72% to 100% and 55% to 100%, respectively, returning from 3 to 7.6 months postoperatively. Failure rates in the BC and LD positions ranged from 0% to 9.4% and 0% to 29%, respectively. There were no differences in reported incidences of neuropraxia, stroke, nonfatal pulmonary embolus, vision loss, cardiac arrest, or other positioning-related complications.

CONCLUSIONS

Arthroscopic management of posterior-inferior shoulder instability has a successful track record and minimal complication profile. Although patient positioning appears to influence results, with those treated in the LD position experiencing marginally higher patient satisfaction and failure rates, the current data prevent any conclusions being made regarding the superiority of one approach over another. As the clinical relevance of patient positioning remains to be determined, larger, higher-level study designs with long-term follow-up are required.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

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).

Posterior Glenohumeral Instability: Evidence-based Treatment

Posterior glenohumeral instability is an increasingly important clinical finding in athletic patients. Over the last decade, basic and clinical research has improved our understanding of the pathoanatomy and biomechanics of this challenging disorder, as well as our ability to diagnose and appropriately treat it. Although recurrent posterior shoulder instability is not as common as anterior instability, it is prevalent among specific populations, including football and rugby players, and may be overlooked by clinicians who are unaware of the typical physical examination and radiographic findings.

Posterior Shoulder Instability

CONTEXT

Posterior shoulder instability has become more frequently recognized and treated as a unique subset of shoulder instability, especially in the military. Posterior shoulder pathology may be more difficult to accurately diagnose than its anterior counterpart, and commonly, patients present with complaints of pain rather than instability. "Posterior instability" may encompass both dislocation and subluxation, and the most common presentation is recurrent posterior subluxation. Arthroscopic and open treatment techniques have improved as understanding of posterior shoulder instability has evolved.

EVIDENCE ACQUISITION

Electronic databases including PubMed and MEDLINE were queried for articles relating to posterior shoulder instability.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

In low-demand patients, nonoperative treatment of posterior shoulder instability should be considered a first line of treatment and is typically successful. Conservative treatment, however, is commonly unsuccessful in active patients, such as military members. Those patients with persistent shoulder pain, instability, or functional limitations after a trial of conservative treatment may be considered surgical candidates. Arthroscopic posterior shoulder stabilization has demonstrated excellent clinical outcomes, high patient satisfaction, and low complication rates. Advanced techniques may be required in select cases to address bone loss, glenoid dysplasia, or revision.

CONCLUSION

Posterior instability represents about 10% of shoulder instability and has become increasingly recognized and treated in military members. Nonoperative treatment is commonly unsuccessful in active patients, and surgical stabilization can be considered in patients who do not respond. Isolated posterior labral repairs constitute up to 24% of operatively treated labral repairs in a military population. Arthroscopic posterior stabilization is typically considered as first-line surgical treatment, while open techniques may be required in complex or revision settings.

Arthroscopic Repair of Posterior Glenohumeral Capsular Rupture With Concomitant Anterior and Posterior Labrum Detachment

Posterior glenohumeral capsular rupture is a rare cause of posterior glenohumeral instability. With advances in imaging and arthroscopic techniques, diagnosis and treatment of posterior glenohumeral instability are becoming more common in practice. We present a technique for arthroscopic repair of a posterior glenohumeral capsular rupture with concomitant anterior and posterior labrum detachment. Arthroscopic fixation was facilitated by use of a 70° arthroscope through an anterior viewing portal to allow accurate placement of the posterior portal in preparation for knot tying. This arthroscopic technique resulted in a successful outcome.

Posterior Instability of the Shoulder: A Systematic Review and Meta-analysis of Clinical Outcomes

BACKGROUND

To date, there are no reports in the literature of a systematic review and meta-analysis for posterior instability of the shoulder.

PURPOSE

The primary objective was to systematically capture, critically evaluate, and perform a meta-analysis of all available literature on arthroscopic clinical outcomes to provide insight and clinical recommendations for unilateral posterior shoulder instability. The secondary objective was to use the same means to assess clinical outcome literature for open treatment, of which a subset of highly reported outcome measures were used to determine superiority of arthroscopic versus open procedures for unilateral posterior shoulder.

STUDY DESIGN

Systematic review, meta-analysis.

METHODS

A systematic search to obtain every available, published, level of evidence study reporting patient data for unidirectional posterior shoulder instability was performed by use of the Cochrane Database of Systematic Reviews, PubMed/Medline database, manual searches of high impact factor journals and conference proceedings, and secondary references appraised for studies meeting inclusion criteria.

RESULTS

The systematic search captured a total of 1035 publications. After initial exclusion criteria were applied, 607 abstracts were assessed for eligibility. Full-text articles were obtained for 324 articles, and a total of 53 unique publications (27 arthroscopic studies, 26 open studies) reporting clinical outcomes for unidirectional posterior shoulder instability met inclusion criteria and were included in the systematic review and meta-analysis.

CONCLUSION

Well-defined and uniform shoulder outcome measures to assess posterior shoulder instability are lacking throughout the literature. However, arthroscopic procedures are shown to be an effective and reliable treatment for unidirectional posterior glenohumeral instability with respect to outcome scores, patient satisfaction, and return to play. Despite similar results of outcome measures to the overall athletic population, throwing athletes are less likely to return to their preinjury levels of sport compared with contact athletes or the overall athletic population. Evidence also indicates that arthroscopic stabilization procedures using suture anchors result in fewer recurrences and revisions than anchorless repairs in young adults engaging in highly demanding physical activity. Furthermore, the literature suggests that patients treated arthroscopically have superior outcomes compared with patients who undergo open procedures with respect to stability, recurrence of instability, patient satisfaction, return to sport, and return to previous level of play.