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

Arthroscopic Management of Posterior Shoulder Instability

Posterior shoulder instability is a distinct subcategory of shoulder instability with an incidence higher than previously reported. Pain is typically the primary complaint, with pathology due to repetitive microtrauma being more common that a specific traumatic event. If nonoperative treatment fails, arthroscopic posterior capsulolabral repair has been shown to result in excellent outcomes and return to sport, with American football players having the best outcomes and throwers being slightly less predictable. Risk factors for surgical failure include decreased glenoid bone width, rotator cuff injury, female gender, and the use of less than 3 anchors.

Biomechanics and Pathoanatomy of Posterior Shoulder Instability

Posterior glenohumeral instability represents a wide spectrum of pathoanatomic processes. A key consideration is the interplay between the posterior capsulolabral complex and the osseous anatomy of the glenoid and humeral head. Stability is dependent upon both the presence of soft tissue pathology (eg, tears to the posteroinferior labrum or posterior band of the inferior glenohumeral ligament, glenoid bone loss, reverse Hill Sachs lesions, and pathologic glenoid retroversion or dysplasia) and dynamic stabilizing forces. This review highlights unique pathoanatomic features of posterior shoulder instability and associated biomechanics that may exist in patients with posterior glenohumeral instability.

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.

Outcomes of arthroscopic stabilization for posterior shoulder instability: a systematic review

BACKGROUND

Posterior shoulder instability makes up approximately 10% of all shoulder instability cases and its diagnosis and treatment is less well understood. Recently, however, there has been increased recognition of posterior instability and posterior stabilization. The purpose of this study was to systematically review the literature to ascertain the outcomes on arthroscopic stabilization of posterior shoulder instability.

METHODS

Two independent reviewers conducted a systematic literature search based on PRISMA guidelines, utilizing the MEDLINE database. Studies were eligible for inclusion if they reported postoperative outcomes for posterior shoulder instability following arthroscopic stabilization.

RESULTS

A total of 48 studies met inclusion criteria for review including 2307 shoulders. Majority of patients were male (83.3%), with an average age of 26.1 years and a mean follow-up of 46.8 months. The functional outcome score primarily utilized for postoperative assessment was the American Shoulder and Elbow Surgeons with an average of 84.77. Overall, 90.9% of patients reported being satisfied with their arthroscopic stabilization. Recurrent instability occurred in 7.4% of patients. The total revision rate was 5.2%. 16.6% of patients reported residual pain postoperatively. The rate of return to play was 86.4% with 68.0% of patients returning to play at the same or higher level of play.

CONCLUSION

Arthroscopic stabilization of posterior shoulder instability resulted in good outcomes with high patient satisfaction and low rates of recurrent instability, revisions, and residual pain.

The Posterior Shoulder Instability Questionnaire: internal consistency, content and criterion validity, responsiveness, and reliability of a new tool for the assessment of posterior shoulder instability

BACKGROUND

Posterior shoulder instability (PSI) is an increasingly recognized cause of shoulder dysfunction particularly in young active patients and certain athlete populations. When evaluating the efficacy of treatment for PSI, specific outcome measures for this population are essential. The aim of the current research was to describe the development and evaluation of a patient reported outcome measure specific for PSI.

METHODS

A retrospective cohort study design of patients with PSI was used to develop and evaluate the "Posterior Shoulder Instability Questionnaire (PSI-Q)". Items for PSI-Q were generated through an expert focus group and existing questionnaires. Preliminary data analysis identified redundancy of items and resulted in the PSI-Q being refined. The final PSI-Q was evaluated on 128 patients with PSI with a structural lesion requiring surgical intervention. Participants were excluded in the absence of a posterior glenohumeral joint lesion. Internal consistency (Cronbach α and corrected item-total correlation), content validity, criterion validity, responsiveness, and test-retest reliability (intraclass correlation coefficient) were examined. Content validity, criterion validity and responsiveness were compared with the Melbourne Instability Shoulder Scale (MISS) and the Western Ontario Shoulder Instability Index (WOSI). The minimum detectable change score (MDC) was calculated.

RESULTS

The Cronbach α for the total scale preintervention and postintervention was high (α = 0.97). All five domains (pain, instability/weakness/stiffness, function, occupation and sport, and quality of life and satisfaction) demonstrated acceptable internal consistency for each subsection and the overall score of the scale (α > 0.70). The corrected-item total correlation for each domain was within an acceptable range. The responsiveness of the PSI-Q questionnaire was excellent (effect size, 2.06; standard response mean, 1.34) and was higher than the MISS and WOSI. There were no relevant floor effects and 1 ceiling effect. Reliability was excellent (intraclass correlation coefficient(1,1) = 0.93) and the calculated MDC was 10.9 points.

DISCUSSION

This study designed and validated a questionnaire specific for measuring symptoms and function in people with structural PSI requiring surgery. The PSI-Q demonstrates good measurement properties and provides an MDC that is useful for researchers and clinicians. In structural PSI, the PSI-Q has a higher responsiveness and more accurately reflects a patient's overall perceived shoulder status compared to current patient reported outcomes for shoulder instability. The psychometric properties of the PSI-Q are still to be determined in a nonsurgical population.

Posterior Shoulder Instability, Part I-Diagnosis, Nonoperative Management, and Labral Repair for Posterior Shoulder Instability-An International Expert Delphi Consensus Statement

PURPOSE

To establish consensus statements on the diagnosis, nonoperative management, and labral repair for posterior shoulder instability.

METHODS

A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating on the basis of their level of expertise in the field. Experts were assigned to 1 of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80% to 89% agreement, whereas strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement.

RESULTS

Unanimous agreement was reached on the indications for nonoperative management and labral repair, which include whether patients had primary or recurrent instability, with symptoms/functional limitations, and whether there was other underlying pathology, or patient's preference to avoid or delay surgery. In addition, there was unanimous agreement that recurrence rates can be diminished by attention to detail, appropriate indication and assessment of risk factors, recognition of abnormalities in glenohumeral morphology, careful capsulolabral debridement and reattachment, small anchors with inferior placement and multiple fixation points that create a bumper with the labrum, treatment of concomitant pathologies, and a well-defined rehabilitation protocol with strict postoperative immobilization.

CONCLUSIONS

The study group achieved strong or unanimous consensus on 63% of statements related to the diagnosis, nonoperative treatment, and labrum repair for posterior shoulder instability. The statements that achieved unanimous consensus were the relative indications for nonoperative management, and the relative indications for labral repair, as well as the steps to minimize complications for labral repair. There was no consensus on whether an arthrogram is needed when performing advanced imaging, the role of corticosteroids/orthobiologics in nonoperative management, whether a posteroinferior portal is required.

LEVEL OF EVIDENCE

Level V, expert opinion.

Posterior Shoulder Instability, Part II-Glenoid Bone Grafting, Glenoid Osteotomy, and Rehabilitation/Return to Play-An International Expert Delphi Consensus Statement

PURPOSE

To establish consensus statements on glenoid bone grafting, glenoid osteotomy, rehabilitation, return to play, and follow-up for posterior shoulder instability.

METHODS

A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating on the basis of their level of expertise in the field. Experts were assigned to 1 of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80% to 89% agreement, whereas strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement.

RESULTS

All of the statements relating to rehabilitation, return to play, and follow-up achieved consensus. There was unanimous consensus that the following criteria should be considered: restoration of strength, range of motion, proprioception, and sport-specific skills, with a lack of symptoms. There is no minimum time point required to return to play. Collision athletes and military athletes may take longer to return because of their greater risk for recurrent instability, and more caution should be exercised in clearing them to return to play, with elite athletes potentially having different considerations in returning to play. The relative indications for revision surgery are symptomatic apprehension, multiple recurrent instability episodes, further intra-articular pathologies, hardware failure, and pain.

CONCLUSIONS

The study group achieved strong or unanimous consensus on 59% of statements. Unanimous consensus was reached regarding the criteria for return to play, collision/elite athletes having different considerations in return to play, indications for revision surgery, and imaging only required as routine for those with glenoid bone grafting/osteotomies at subsequent follow-ups. There was no consensus on optimal fixation method for a glenoid bone block, the relative indications for glenoid osteotomy, whether fluoroscopy is required or if the labrum should be concomitantly repaired.

LEVEL OF EVIDENCE

Level V, expert opinion.

Risk Factors Associated with First Time and Recurrent Shoulder Instability: A Systematic Review

Background

Shoulder instabilities constitute a large proportion of shoulder injuries and have a wide range of presentations. While evidence regarding glenohumeral dislocations and associated risk factors has been reported, less is known regarding the full spectrum of instabilities and their risk factors.

Purpose

The purpose of this systematic review was to identify modifiable risk factors to guide patient management decisions with regards to implementation of interventions to prevent or reduce the risk of shoulder instability.

Study Design

Systematic Review.

Methods

A systematic, computerized search of electronic databases (CINAHL, Cochrane, Embase, PubMed, SportDiscus, and Web of Science) was performed. Inclusion criteria were: (1) a diagnosis of shoulder instability (2) the statistical association of at least one risk factor was reported, (3) study designs appropriate for risk factors, (4) written in English, and (5) used an acceptable reference standard for diagnosed shoulder instability. Titles and abstracts were independently screened by at least two reviewers. All reviewers examined the quality studies using the Newcastle-Ottawa Scale (NOS). At least two reviewers independently extracted information and data regarding author, year, study population, study design, criterion standard, and strength of association statistics with risk factors.

Results

Male sex, participation in sport, hypermobility in males, and glenoid index demonstrated moderate to large risk associated with first time shoulder instability. Male sex, age \<30 years, and history of glenohumeral instability with concomitant injury demonstrated moderate to large risk associated with recurrent shoulder instability.

Conclusion

There may be an opportunity for patient education in particular populations as to their increased risk for suffering shoulder instability, particularly in young males who appear to be at increased risk for recurrent shoulder instability.

Level of Evidence

Level III.

Translation, cross-cultural adaptation, and validation of the Turkish version of the shoulder instability-return to sport (SI-RSI) after injury scale

To translate and culturally adapt the shoulder instability-return to sport after injury (SI-RSI) scale into Turkish (SI-RSI-Tr) and examine the psychometric properties of the Turkish version of athletes following a traumatic shoulder instability. The SI-RSI was translated into Turkish using Beaton guidelines. Sixty-nine patients with shoulder instability completed the translated SI-RSI, Western Ontario Shoulder Instability Index (WOSI), the Tampa Scale of Kinesiophobia (TSK), and the Walch-Duplay Scores. We analysed the internal consistency, agreement, reliability, and validity of the SI-RSI-Tr. The SI-RSI-Tr demonstrated excellent internal consistency (Cronbach's alpha = 0.92), test-retest reliability (ICC = 0.95), and feasibility with no ceiling or floor effect. SI-RSI-Tr correlated with WOSI total score (r = -0.824, p < 0.001), its subscales: WOSI-physical (r = -0.683, p < 0.001), WOSI-sports (r = -0.832, p < 0.001), WOSI-lifestyle (r = -0.739, p < 0.001), and WOSI-emotions (r = -0.734, p < 0.001) respectively), Walch-Duplay (r = 0.840, p < 0.001) and TSK (r = -0.828, p < 0.001) scores. The Turkish SI-RSI is a reliable, internally consistent, and valid tool for athletes with shoulder instability. Researchers and clinicians could safely use the SIRSI-Tr to evaluate the shoulder-specific psychological factors on return to sports following an episode of shoulder instability.

Two-Portal Arthroscopic Knotless All-Suture Anchor Posterior Labral Repair

Isolated posterior shoulder instability accounts for approximately 10% of shoulder instability cases. Patients may present after an acute trauma or with insidious onset and associated posterior shoulder pain. Knotless and all-suture anchor devices have become increasing popular and are often used in arthroscopic shoulder instability cases to avoid knot stacks and allow for the ability to re-tension the fixation. This technical note describes our technique for 2-portal posterior labral repair using knotless all-suture anchors with the patient in the lateral decubitus position.

Posterior Shoulder Instability and Glenoid Bone Loss: A Review and a Free Bone Graft Technique

Posterior glenoid bone loss (pGBL) is frequently associated with posterior shoulder instability. Posterior glenohumeral instability accounts for a small percentage of shoulder pathologies, and critical bone loss in posterior instability has not been well defined in the literature. Younger patient populations who participate in activities that repetitively stress the posterior stabilizing structures of the shoulder are more prone to developing posterior shoulder instability. A variety of surgical options have been described, ranging from isolated capsulolabral repair to glenoid osteotomy. Soft-tissue repair alone may be an inadequate treatment in cases of pGBL and places patients at a high risk of recurrence. Our preferred technique for posterior glenoid reconstruction in cases of pGBL involves the transfer of a free iliac crest bone graft onto the native glenoid. The graft is contoured to fit the osseous defect and secured to provide an extension of the glenoid track. In this study, we review pGBL in the setting of posterior instability and describe our technique in detail. Further long-term studies are needed to refine the indications for glenoid bone graft procedures and quantify what constitutes a critical pGBL.

No Difference in Recurrent Instability Between Knotted and Knotless Repair Techniques in Arthroscopic Treatment of Isolated Posterior Labral Tears: A Systematic Review

Purpose

To compare clinical failure, recurrent instability, patient-reported outcome measures (PROMs), and return to sport (RTS) between knotted and knotless fixation methods in arthroscopic posterior labral repair for isolated posterior shoulder instability (PSI).

Methods

Multiple databases were queried according to Preferred Reported Items for Systematic Reviews and Meta-Analyses guidelines for clinical studies with Level I to IV evidence, including knotted and knotless suture anchors for arthroscopic posterior labral repair. Combined anterior and posterior instability, multidirectional instability, SLAP injuries, unspecified repair techniques, majority open procedures, and revision surgery were excluded.

Results

Screening yielded 17 full-text articles reporting on 852 shoulders undergoing posterior labral repair. Recurrent instability ranged from 0% to 21%, and the rate of revision surgery ranged from 0% to 11% in knotted only, 0% in knotless only, and 2.0% to 8.1% in knotted and knotless studies. Six studies with both pre- and postoperative visual analog scale scores and 7 studies with both pre- and postoperative American Shoulder and Elbow Score scores all showed improvement in scores after intervention regardless of repair technique. Thirteen studies reported RTS or duty rates with a minimum of 79%.

Conclusions

Overall recurrent instability after posterior labral repair for isolated PSI was low with improvement in PROMs and favorable RTS rates regardless of fixation method. There was no clear difference in recurrent instability or revision surgery between knotted and knotless fixation methods for isolated posterior labral repair. However, the current literature is predominantly limited by Level III and IV evidence. The quality of literature and lack of standardization on the definition of clinical failure and recurrent instability among surgeons preclude any definitive conclusion regarding one clinically superior fixation method.

Level of Evidence

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

Diagnosing the direction of shoulder instability in rugby players

The muscular characteristics of rugby players may make diagnosing the direction of shoulder instability and labral pathology challenging. This study aimed to assess the accuracy of clinical examination and specifically instability tests, in diagnosing the direction of shoulder instability in rugby players. One-hundred-and-forty rugby players, who had undergone a shoulder stabilization procedure, over a 55-month period, were included in this study. The mean age was 21.5 years with 137 males. Data collected included clinical examination and intraoperative findings. The two were compared to calculate the diagnostic accuracy of special tests for instability. The Anterior Apprehension Test had good sensitivity (82.7%), specificity (100%) and PPV (100%) but poor NPV (55.8%). All posterior instability tests demonstrated a sensitivity of over 85%, but all had a specificity of 25% or less. In 83.6% of cases the direction of instability was correctly identified from history and examination. Anterior instability was correctly diagnosed in 78.9% of cases and posterior in 100.0%. The poor NPV of the anterior apprehension test suggests that clinicians should be suspicious of anterior instability in rugby shoulders even in the light of negative examination findings. Positive posterior instability tests are highly suggestive of posterior instability in rugby players.

Favorable short-term outcomes of micronized allogenic cartilage scaffold for glenoid cartilage defects associated with posterior glenohumeral instability

Purpose

To determine clinical outcomes associated with micronized allogenic cartilage scaffold use for treatment of posterior glenoid cartilage defects at 2 years.

Study Design

Case series.

Methods

A retrospective analysis of prospectively collected data was performed on a consecutive series of patients who underwent arthroscopic treatment of a symptomatic posterior glenoid cartilage defect with micronized allogenic cartilage scaffold between January 2019 and December 2020. The primary outcome was subjective shoulder value (SSV) at latest follow-up. Secondary outcomes included visual analog scale (VAS), recurrence of instability, and range of motion (ROM).

Results

Seven patients, including 4 in the setting of primary posterior instability and 3 in the setting of recurrent symptoms after arthroscopic posterior glenohumeral stabilization, were included in the analysis with a mean follow up of 2.6 years (range, 2-3.7 years). Statistically significant improvements were seen in SSV (median = 40, interquartile range [IQR] = 40-50 before surgery; vs median = 85, IQR = 67.5-87.5 after surgery; P = .018) and VAS (median = 4, IQR = 4-6.3 before surgery; vs median = 1, IQR = 0-1.5 after surgery; P = .010). No significant differences were seen in ROM. There were no cases of recurrent instability or reoperation.

Conclusions

The use of micronized allogenic cartilage scaffold for glenoid cartilage defects is associated with clinical improvement at 2-year follow-up. This is the case when performed in conjunction with index posterior labral repair when there is a concomitant glenoid cartilage defect or when performed in the setting of persistent pain and mechanical symptoms after prior posterior labral repair.

Level of Evidence

Level IV, therapeutic case series.

Does glenoid bone loss accompany posterior shoulder instability with only labral tear? A magnetic resonance imaging-based study

BACKGROUND

The primary aim of this study was to investigate bone loss in the glenoid with magnetic resonance imaging in posterior shoulder instability with only a labral tear.

METHODS

A total of 76 patients operated on because of posterior and anteroposterior shoulder instability only with a labral tear between 2006 and 2019 (n = 40 and n = 36, respectively) were included in this study. The instability type, a presence of an additional superior labrum anteroposterior (SLAP) lesion, the number of dislocations, and the magnetic resonance imaging-based measurements (the glenoid diameter and the bone defect size in the glenoid, the Hill-Sachs lesion [HSL] and the reverse HSL [rHSL] length, the angle and the arc length of HSL and rHSL, and the humerus head diameter and its area) were analyzed.

RESULTS

The size of the anterior glenoid defect, the rHSL measurements (length, angle, and arc length), and the ratio of the anterior glenoid defect size to the glenoid diameter were significantly higher for anteroposterior instability (P < .01) cases. There was no significant difference (P = .49, .64, and .82, respectively) for the presence of an additional SLAP pathology, the glenoid diameter, the posterior glenoid defect, and the ratio of the posterior glenoid defect size to the glenoid diameter in posterior and anteroposterior instability groups. The increased number of dislocations was associated with increased rHSL length and total arc length (P = .04 and .03, respectively). An additional SLAP lesion in posterior shoulder instabilities was not associated with the bone defect size (P = .29).

CONCLUSION

Although the posterior shoulder instability with only a labral tear is likely to cause a bone defect, we have shown that the instability is not expected to be caused by the bone defect. Therefore, this study points out that only soft tissue repair without considering the bone defect could be promising in this patient group.

Posterior Dislocation of the Shoulder: The Light-Bulb Sign

Posterior dislocation is a rather rare injury, often misdiagnosed. The current report offers valuable insights regarding the anatomical background of this clinical entity and emphasizes the 'light-bulb sign,' which can be observed in anterior-posterior shoulder X-rays when there is a posterior dislocation. It is crucial for healthcare professionals, including emergency department physicians, radiologists, general practitioners, orthopedic surgeons, and other relevant medical experts, to be well-acquainted with this sign and maintain a heightened awareness when encountering such cases. A 57-year-old male presented to the Emergency Department due to right shoulder pain immediately after an epileptic seizure. His arm was locked in internal rotation, while the initial X-rays, although did not reveal evident malalignment, showed the light-bulb sign. Further imaging with a computer tomography (CT) scan exhibited a large (50%) reverse Hill-Sachs defect. The patient was treated surgically with hemiarthroplasty. The light-bulb sign should be a red flag for physicians who evaluate these patients or these X-rays. The patient's history, such as epileptic seizures and examination, especially the locked arm in internal rotation, are of paramount importance for not misdiagnosing these cases.

Outcomes After Revision Posterior Shoulder Capsulolabral Repair in Adolescent Athletes

Background

Few studies have evaluated the outcomes of posterior arthroscopic capsulolabral repair in adolescents, especially with regard to outcomes after revision repair.

Hypothesis

Adolescent athletes who undergo revision arthroscopic posterior unidirectional capsulolabral repair will have similar outcomes and return to play when compared with adolescent athletes who underwent primary arthroscopic posterior unidirectional capsulolabral repair.

Study Design

Cohort study; Level of evidence, 3.

Methods

Data were reviewed from patients who underwent posterior shoulder stabilization between 2000 and 2019 and had a minimum follow-up of 2 years. Patients <11 and >19 years of age and those with multidirectional instability were excluded. Revision surgery was defined as repeat arthroscopic posterior capsular repair. The ability to return to sport (and level of sport), clinical outcomes scores (American Shoulder and Elbow Surgeons [ASES] and visual analog scale for pain), and patient-reported perception of range of motion, strength, and satisfaction were recorded. Comparisons between the primary and revision cohorts were made using the chi-square or the Mann-Whitney U test.

Results

Included were 180 adolescent patients (182 shoulders) who underwent a primary unidirectional posterior stabilization, with an average follow-up of 6.1 years. Of these patients, 17 patients required revision surgery (9.3% revision rate). At the final follow-up, patients who underwent revision surgery returned to sport at similar rates to those who did not (70.6% vs 85.9%; P = .095) and were similarly likely to return to their presurgery level of play (41.1% vs 23.7%; P = .10). The no-revision patients had higher ASES scores (76.1 vs 87.1; P = .007) as well as less pain and improved subjective range of motion scores. However, both groups had similar subjective strength scores, and both reported that surgical repair was satisfactory (no revision, 93.2% vs revision, 88.2%; P = .45).

Conclusion

Adolescent athletes had a low risk of revision surgery and frequently returned to play after arthroscopic posterior capsulolabral repair, often at a lower level of play. Those who required revision surgery had poorer outcome scores but still reported a high rate of satisfaction.

Trends in the surgical treatment of posterior shoulder instability in the United States from 2016 to 2020

Background

The purpose of this study was to describe trends in the incidence of open versus arthroscopic management of posterior shoulder instability (PSI) as well as the patients undergoing these procedures in the United States over time.

Methods

The PearlDiver Patient Records Database was utilized for this study. Cases of PSI and surgery were identified via the appropriate ICD-10-CM and CPT codes. Linear regression and two-sample Student's t-test were used to analyze incidence rates, procedure type, number of instability events, and patient age.

Results

A total of 5655 patients were identified as having PSI, undergoing a total of 686 capsulorraphies. The incidence of PSI treated surgically increased across the years of the study at a rate of 0.0293 per 100,000 person-years with an incidence in 2019-2020 greater than in 2016-2018 (p = 0.0151). Patients undergoing arthroscopic capsulorrhaphy were on average younger than those undergoing open capsulorrhaphy (p = 0.0021). Patients experienced a higher number of posterior instability events before open surgery compared to arthroscopic (p = 0.0274).

Discussion

The incidence of surgical treatment of PSI in the United States is steadily rising, with greater than 90% of cases being treated arthroscopically. Those undergoing arthroscopic posterior stabilization are both younger and face fewer instability events prior to 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.

Arthroscopic Posterior Bankart Repair Using the Wilmington Portal to Facilitate Suture Anchor Implantation

Posterior shoulder instability (PSI) accounts for 2% to 10% of all shoulder instability, with recurrent posterior subluxation being the most common type. One of the most important risk factors is the presence of an anterior humeral notch (so-called reverse Hill-Sachs lesion), and the most common lesion in PSI is a posterior labral lesion. When conservative treatment fails, surgery is recommended to provide long-term stability, manage pain, and enable a return to previous activity levels. Most posterior labral tears are treated by an arthroscopic posterior Bankart procedure. Visualization of the posterior aspect of the glenohumeral joint is technically challenging in this procedure. The instrumental portal is also a matter of concern because there is no rotator interval posteriorly for cannula placement. The purpose of this article is to propose a technique using a secondary posterolateral Wilmington instrumental portal to perform easy and reproducible placement of the posterior suture anchor at a 45° angle to the glenoid rim. We recommend implementing this technique in patients with painful PSI or with a type B2 lesion according to the Moroder classification.

Posterior Labral Repair Using Knotless "All-Suture" Suture Anchors

Isolated posterior instability is well described but relatively uncommon, accounting for less than 10% of all shoulder instability cases. When nonoperative management fails, surgical outcomes demonstrate improved patient-reported outcomes with a high level of return to sport. Knotless suture anchor and "all-suture" suture anchor technology are now available and used for instability procedures in the shoulder. This technical description describes knotless "all-suture" suture anchor fixation for isolated posterior labral tears.

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.

Lack of Consensus in Rehabilitation Protocols After Posterior Shoulder Stabilization

Background

Posterior shoulder instability is being identified and treated more frequently by orthopaedic providers. After posterior shoulder stabilization, long-term outcomes in function and mobility are largely dependent on the postoperative rehabilitation period. Thus, it is important to assess the consistency between protocols at different institutions.

Purpose/Hypothesis

The purpose of this study was to investigate the variability among rehabilitation protocols published by academic orthopaedic programs and their affiliates. It was hypothesized that there would be little consistency in the duration of immobilization, timing of functional milestones, and start dates of various exercises.

Study Design

Cross-sectional study.

Methods

Rehabilitation protocols after posterior shoulder stabilization that were published online from Accreditation Council for Graduate Medical Education (ACGME)-accredited orthopaedic surgery programs and their affiliates were evaluated for recommendations on immobilization, exercises, activities, range of motion (ROM), and return-to-sport goals.

Results

Of the 204 ACGME-accredited orthopaedic surgery programs, 22 programs and 17 program affiliates had publicly available rehabilitation protocols that were included for review. There were 37 programs (94.9%) that recommended the use of sling immobilization for a mean of 4.7 ± 1.8 weeks postoperatively. Active ROM of the elbow, wrist, and hand was the most common early ROM exercise to be recommended (36 programs; 92.3%). The goal of 90° passive external rotation demonstrated the widest range of recommended start dates (0-12 weeks postoperatively). Late ROM exercises and start dates varied between protocols, with the largest standard deviation found in achieving full active ROM (13.5 ± 3.6 weeks). Resistance exercises showed a wide range of recommended start dates. Bench presses and push-ups began, on average, at 13.1 ± 3.4 and 15.3 ± 3.2 weeks, respectively. Return to sport was recommended at 21.7 ± 3.6 weeks.

Conclusion

There was a high level of variability in postoperative rehabilitation protocols after posterior shoulder stabilization among orthopaedic programs and their affiliates, suggesting that a standard protocol for rehabilitation has yet to be established.

Arthroscopic Posterior Capsulolabral Repair With Suture-First Versus Anchor-First Technique in Patients With Posterior Shoulder Instability (Type B2): Clinical Midterm Follow-up

Background

Isolated soft tissue injuries of the posterior capsulolabral complex can be addressed arthroscopically, with various anchor systems available for repair.

Purpose

To evaluate clinical and patient-reported outcomes after arthroscopic capsulolabral repair in patients with posterior shoulder instability (PSI) and to compare differences in outcomes between patients treated with a suture-first technique (PushLock anchor) and an anchor-first technique (FiberTak all-suture anchor).

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 32 patients with dynamic structural PSI (type B2 according to the ABC classification) treated with an arthroscopic posterior capsulolabral repair. After a mean follow-up time of 4.8 ± 3.4 years (range, 2-11) patients were evaluated clinically, and standardized outcome scores were obtained for the Subjective Shoulder Value (SSV), the Western Ontario Shoulder Instability Index (WOSI), Rowe, Kerlan-Jobe Orthopaedic Clinic (KJOC), patient satisfaction (0-5 [best]), and pain on a visual analog scale (VAS; 0-10 [worst]).

Results

The overall satisfaction level with the outcome of the surgery was 4.6 ± 0.5 (range, 4-5). No patient suffered from instability events. The mean VAS level for pain was 0.4 ± 0.9 (range, 0-4) at rest and 1.9 ± 2.0 (range, 0-6) during motion. The mean SSV was 80 ± 17 (range, 30-100), the mean postoperative WOSI score 75% ± 19% (range, 18-98), the mean Rowe score 78 ± 20 (range, 10-100), and the mean KJOC score was 81 ± 18 (range, 40-100) for the entire cohort. There was no significant difference between the techniques with regard to range of motion, strength, or clinical outcome scores.

Conclusion

Arthroscopic posterior capsulolabral repair was a satisfactory method to treat structural PSI type B2 with regard to stability, pain relief, and functional restoration. The majority of patients had good outcomes. No differences in outcomes were observed between the anchor-first and suture-first techniques.

Portal Closure After Segmental Posterior Labral Repair for Posterior Shoulder Instability

Posterior instability, although an uncommon shoulder pathology, is reported most frequently in the athletic population. Arthroscopic repair has emerged as the main surgical treatment modality for posterior instability. However, when compared with arthroscopic repair for anterior instability, the results of this procedure remain suboptimal. The creation of iatrogenic defects in the capsule, due to cannula placement, is a possible culprit. Because these defects typically do not heal satisfactorily, they become stress risers within the capsule itself, which may lead to recurrent instability or an otherwise compromised repair construct. Therefore, we find that routine intraoperative repair of these defects after repair can reduce the risk of injury and possibly improve long-term outcomes. In this article, we illustrate the repair of a posterior segmental tear using all-suture knotless implants with closure of the posterior and posterior-inferior portals after stabilization.

Posterior Glenoid Bone Loss and Instability: An Evidence-based Approach to Diagnosis and Management

Posterior glenohumeral instability is an underappreciated cause of disability that may necessitate surgical intervention to allow functional glenoid restoration. However, posterior glenoid bone abnormalities, when sufficiently severe, may contribute to persistent instability despite a well-performed capsulolabral repair. Recognition and understanding of these lesions is critical to both surgical decision making and execution of the surgical plan. Numerous procedures have been described to address posterior instability including recent developments in arthroscopic grafting techniques. The purpose of this article was to provide an evidence-based strategy for diagnosis and management of posterior shoulder instability and glenoid bone loss.

Glenoid Bone Loss Pattern in Patients With Posterior Instability Versus Anterior Instability: A Matched Cohort Study

Background

The pattern of glenoid bone loss (GBL) in anterior glenohumeral instability is well described. It was recognized recently that posterior GBL after instability has a posteroinferior pattern.

Purpose/Hypothesis

The purpose of this study was to compare GBL patterns in a matched cohort of patients with anterior versus posterior glenohumeral instability. The hypothesis was that the GBL pattern in posterior instability would be more inferior than the GBL pattern in anterior instability.

Study Design

Cohort study; Level of evidence, 3.

Methods

In this multicenter retrospective study, 28 patients with posterior instability were matched with 28 patients with anterior instability by age, sex and number of instability events. GBL location was defined using a clockface model. Obliquity was defined as the angle between the long axis of the glenoid and a line tangent to the GBL. Superior and inferior GBL were measured as areas and defined relative to the equator. The primary outcome was the 2-dimensional characterization of posterior versus anterior GBL. The secondary outcome was a comparison of the posterior GBL patterns in traumatic and atraumatic instability mechanisms in an expanded cohort of 42 patients.

Results

The mean age of the matched cohorts (n = 56) was 25.2 ± 9.87 years. The median obliquity of GBL was 27.53° (interquartile range [IQR], 18.83°-47.38°) in the posterior cohort and 9.28° (IQR, 6.68°-15.75°) in the anterior cohort (P < .001). The mean superior-to-inferior bone loss ratio was 0.48 ± 0.51 in the posterior cohort and 0.80 ± 0.55 (P = .032) in the anterior cohort. In the expanded posterior instability cohort (n = 42), patients with traumatic injury mechanism (n = 22), had a similar GBL obliquity compared to patients with an atraumatic injury mechanism (n = 20) (mean, 27.73° [95% CI, 20.26°-35.20°] vs 32.20° [95% CI, 21.27°-43.14°], respectively) (P = .49).

Conclusion

Posterior GBL occurred more inferiorly and at an increased obliquity compared with anterior GBL. This pattern is consistent for traumatic and atraumatic posterior GBL. Bone loss along the equator may not be the most reliable predictor of posterior instability, and critical bone loss may be reached more rapidly than a model of loss along the equator may predict.

Posterior Shoulder Instability in the Military and Athlete: An Evidence and Experience-Based Treatment Approach

Background:

Recognition of posterior glenohumeral instability has increased in young, athletic populations, leading to evolution in operative approaches to management. As with anterior instability surgery, successful treatment for these challenging injuries is dependent on understanding the key principles of pathology and restoration of the functional anatomy.

Indications:

Operative management of posterior glenohumeral instability is indicated for recurrent instability events or persistent pain refractory to physical therapy in the setting of posterior labral pathology with or without bone loss.

Technique:

In this video article, we present our approach to operative management of posterior glenohumeral instability in a young, athletic population, as developed through extensive experience in military and athlete populations and supported by research. Our approach to posterior glenohumeral instability is to restore the functional anatomy of the bone, labrum, and capsuloligamentous static restraints. We consider concomitant pathology and bone loss as components of these restraints that need to be restored to achieve a stable, painless shoulder. Using standard portals and tools, we prepare the glenoid and mobilize the labrum. When present, large osseous lesions can be restored using allograft distal tibia. We then repair and superiorize the inferior labrum, taking care to create a secure buttress against translation by positioning anchors at the edge of the chondral surface and everting the interior flap of tissue. If capsular pathology is present, this is also addressed. In the setting of significant posterior glenoid bone loss, we reconstruct the osseous support with a distal tibial allograft, which we perform arthroscopically and augment with labral repair. Using these techniques, surgeons can expect a low overall failure rate. In our young, highly active population, we observed 17.2% failure by 5 years, although this is dependent on multiple factors including age and bone loss.

Discussion:

Outcomes for posterior glenohumeral instability can be excellent with both nonoperative and operative treatments. When operative intervention is pursued, it is important to critically evaluate the anatomy, place portals considerately, and functionally restore the damaged structures.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Arthroscopic Stabilization of Posterior Shoulder Instability Without Glenoid Bone Loss

Background:

Contact athletes who experience posterior shoulder instability have a high likelihood of recurrence necessitating surgery.

Indications:

Patients with posterior shoulder instability without glenoid or humeral head bone loss who have failed activity modification, bracing, and physical therapy may benefit from arthroscopic stabilization surgery.

Technique Description:

We describe a technique for arthroscopic labral repair with capsular plication through 4 portals in the lateral decubitus position.

Results:

Arthroscopic capsulolabral reconstruction is an effective and reliable treatment for posterior shoulder instability with good patient-reported outcomes, low recurrence rates, and high rate of return-to-play.

Discussion/Conclusion:

Arthroscopic capsulolabral reconstruction in the lateral decubitus position with appropriately placed portals allows for safe and effective repair of the labrum and capsular plication to address posterior shoulder instability. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Arthroscopic Posterior Labral Repair in Active-Duty Military Patients: A Reliable Solution for an At-Risk Population, Regardless of Anchor Type

BACKGROUND

Active-duty servicemembers are a population at risk for the development of posterior shoulder instability. While short-term outcomes after arthroscopic posterior labral repair for posterior shoulder instability are promising, there is a paucity of longer term follow-up data for this procedure.

PURPOSES

The primary purpose was to report midterm outcomes after arthroscopic posterior labral repair in active-duty military patients for posterior shoulder instability without bone loss. The secondary purpose was to determine if outcomes varied between anchor types used.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Preoperative and postoperative outcomes, with a minimum 3-year follow-up, for a visual analog scale for pain, the Single Assessment Numeric Evaluation (SANE), the American Shoulder and Elbow Surgeons (ASES) score, and the Rowe score were collected and analyzed. A separate subgroup analysis was performed comparing the outcomes of patients who underwent repair with biocomposite anchors versus those who underwent repair with all-suture anchors.

RESULTS

A total of 73 patients with a mean follow-up of 82.55 ± 24.20 months met the inclusion criteria and were available for analysis. As a whole, the cohort demonstrated statistically and clinically significant improvements in outcome scores at final follow-up. Preoperative and postoperative range of motion did not vary significantly. While the difference in final outcome scores between the 2 anchor types did not reach statistical significance, a statistically significantly larger proportion of patients who underwent repair with all-suture anchors versus those who underwent repair with biocomposite anchors met the Patient Acceptable Symptom State for the SANE (97.14% vs 78.95%, respectively; P = .0180) and the ASES score (88.57% vs 68.42%, respectively; P = .0171). The proportion of patients who achieved the substantial clinical benefit or surpassed the minimal clinically important difference, however, did not vary by anchor type. Overall, 70 patients (95.89%) remained on active duty and were able to return to preinjury work and recreational activity levels. There were 3 patients (4.11%) who had recurrent posterior instability.

CONCLUSION

This population of active-duty servicemembers undergoing posterior labral repair for posterior labral instability without bone loss demonstrated a statistically and clinically significant improvement in midterm outcomes, a low recurrence rate, and a rate of return to active duty of 95.89%, regardless of the anchor type used.

Single-Portal Arthroscopic Posterior Capsulorrhaphy for Recurrent Shoulder Capsule Laxity and Instability

Arthroscopic stabilization for posterior shoulder instability is well documented in the literature, offering good to excellent clinical outcomes after injury with favorable return-to-sport and patient satisfaction rates. Posterior capsulorrhaphy addresses recurrent laxity by decreasing the size of the posterior capsule through arthroscopic placement of sutures, in addition to addressing posterior labral tears and any intra-articular pathology within the joint. This technical note describes an arthroscopic posterior capsulorrhaphy for recurrent posterior shoulder capsule laxity and instability in an active patient. This technique uses a single posterior working portal and 2 suture anchors to tighten the posterior capsule onto the intact labrum.

Comprehensive management of posterior shoulder instability: diagnosis, indications, and technique for arthroscopic bone block augmentation

Recurrent posterior glenohumeral instability is an entity that demands a high clinical suspicion and a detailed study for a correct approach and treatment. Its classification must consider its biomechanics, whether it is due to functional muscular imbalance or to structural changes, volition, and intentionality.

Due to its varied clinical presentations and different structural alterations, ranging from capsule-labral lesions and bone defects to glenoid dysplasia and retroversion, the different treatment alternatives available have historically had a high incidence of failure.

A detailed radiographic assessment, with both CT and MRI, with a precise assessment of glenoid and humeral bone defects and of glenoid morphology, is mandatory.

Physiotherapy focused on periscapular muscle reeducation and external rotator strengthening is always the first line of treatment. When conservative treatment fails, surgical treatment must be guided by the structural lesions present, ranging from soft tissue repair to posterior bone block techniques to restore or increase the articular surface.

Bone block procedures are indicated in cases of recurrent posterior instability after the failure of conservative treatment or soft tissue techniques, as well as symptomatic demonstrable nonintentional instability, presence of a posterior glenoid defect >10%, increased glenoid retroversion between 10 and 25°, and posterior rim dysplasia. Bone block fixation techniques that avoid screws and metal allow for satisfactory initial clinical results in a safe and reproducible way.

An algorithm for the approach and treatment of recurrent posterior glenohumeral instability is presented, as well as the author’s preferred surgical technique for arthroscopic posterior bone block.

Patient Age and Surgical Intervention as Risk Factors for the Development of Osteoarthritis After Posterior Shoulder Instability: A Population-Based Study

Background

Diagnosis and treatment of posterior shoulder instability (PSI) has improved with advances in imaging and surgical technique. However, the relationship between PSI and osteoarthritis (OA) remains unclear.

Purpose

To evaluate a population-based cohort to (1) determine the rate of symptomatic OA, (2) identify patient characteristic risk factors for OA, and (3) evaluate the effect of posterior capsulolabral repair on OA progression.

Study Design

Case-control study; Level of evidence, 3.

Methods

After review of 324 patient records, we included 115 patients (14 female, 101 male) diagnosed with PSI between January 1994 and July 2012 with an average follow-up of 12.5 years (range, 5-23 years). Medical records were reviewed for patient characteristics, injury characteristics, surgical details (if any), and radiographic progression of OA. Kaplan-Meier survival was used to estimate survival free of OA; characteristics associated with OA progression were determined via univariate Cox regression models, and associated 95% CIs and hazard ratios (HRs) are presented.

Results

Overall, 14% (16/115) of patients had radiographic progression of symptomatic glenohumeral arthritis, with 5-year survival of 88.3% (95% CI, 79.7%-97.3%). Older age at the time of instability diagnosis was associated with arthritis progression (10-year unit HR, 1.95; 95% CI, 1.26-3.03). Patients who underwent surgery demonstrated increased radiographic progression of OA (HR, 4.03; 95% CI, 1.23-13.23). There was a trend of increased OA in patients treated with labral debridement compared with repair despite lower baseline levels of OA; however, this difference was not statistically significant (P = .09).

Conclusion

Symptomatic glenohumeral arthritis is not seen routinely in patients with PSI. Although uncommon, an age of at least 30 years at the time of diagnosis and surgical intervention were identified as risk factors for developing symptomatic arthritis at long-term follow-up.

Return to Sport After Surgical Management of Posterior Shoulder Instability: A Systematic Review and Meta-analysis

BACKGROUND

Posterior shoulder instability accounts for a small proportion of all shoulder instability, although it can affect athletes of all types, from contact to overhead athletes. Surgical treatment is quite successful in these patients; however, the literature reports a wide range of rates of return to sport.

PURPOSE/HYPOTHESIS

The purpose was to determine the return-to-sport rates after surgical stabilization for posterior shoulder instability. It was hypothesized that patients would experience a high rate of return to sport.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Embase, PubMed, and MEDLINE were searched for relevant literature from database inception until April 2020, and studies were screened by 2 reviewers independently and in duplicate for studies reporting rates of return to sport after surgical management of posterior shoulder instability. Demographic data as well as data on return to sport and functional outcomes were recorded. A meta-analysis of proportions was used to combine the rates of return to sport using a random effects model. A risk of bias was assessed for all included studies.

RESULTS

Overall, 32 studies met inclusion criteria and comprised 1100 patients (1153 shoulders) with a mean age of 22.8 years (range, 11-65) and a mean follow-up of 43.2 months (range, 10-228). The pooled rate of return to any level of sport was 88% (95% CI, 84%-92%; I² = 68.7%). In addition, the pooled rate of return to the preinjury level was 68% (95% CI, 60%-76%; I² = 79%). Moreover, the pooled return-to-sport rate for contact athletes was 94% (95% CI, 90%-97%; I² = 0%), while for throwing athletes it was 88% (95% CI, 83%-92%; I² = 0%).

CONCLUSION

Surgical management of posterior shoulder instability resulted in a high rate of return to sport, as well as significant pain reduction and functional improvement in most patients. However, only two-thirds of athletes can return to their preinjury levels of sport.

Nonoperative Management of Posterior Shoulder Instability: What Are the Long-Term Clinical Outcomes?

OBJECTIVE

To report the injury characteristics, radiographic findings, and long-term outcomes of nonoperative management for posterior shoulder instability (PSI).

DESIGN

A retrospective review of 143 patients with PSI using a large geographic database.

SETTING

Single county between January 1994 and July 2012.

PATIENTS

A clinical history and diagnosis of PSI, one confirmatory imaging study to support the diagnosis, and a minimum of 5 years follow-up were required for inclusion. Patients with seizure disorders, anterior-only instability, multidirectional instability, and superior labrum from anterior to posterior diagnosis were excluded.

INTERVENTIONS

Patients with PSI were managed nonoperatively or operatively.

MAIN OUTCOME MEASURES

Pain, recurrent instability, and progression into glenohumeral osteoarthritis at long-term follow-up.

RESULTS

One hundred fifteen patients were identified. Thirty-seven (32%) underwent nonoperative management. Twenty (54%) patients were diagnosed with posterior subluxation, 3 (8%) with a single dislocation, and 7 (19%) with multiple dislocations. Symptomatic progression of glenohumeral arthritis was observed in 8% (3) of patients. Pain improved in 46% (17) of patients and worsened in 19% (7). Recurrent instability and progression to osteoarthritis occurred in 15% (3/20) of patients with a traumatic instability event compared with 0% of atraumatic patients after nonoperative management (P = 0.234). Pain at follow-up was more common in nonoperative than operative patients (P = 0.017).

CONCLUSIONS

Nonoperative management is a viable option for many patients with posterior shoulder instability; however, many may continue to have posterior shoulder pain.

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.

Management of common upper extremity injuries in throwing athletes: a critical review of current outcomes

Given the rising incidence and prevalence of shoulder injuries in throwing athletes, this review aims to evaluate management options and outcomes of common shoulder injuries in overhead throwers. Laxity of the glenohumeral joint is often adaptive for overhead athletes to achieve the velocity necessary to compete in the professional ranks. Surgical repair of the stabilizers of the humeral head-specifically the labrum and rotator cuff-often causes inflammation, scarring, and overtensioning of the glenohumeral joint which lead to poor postoperative performance. Thus, nonsurgical management should be exhausted in this population before considering surgical intervention.

Management of Locked Posterior Shoulder Dislocation with Reverse Hill-Sachs Lesions via Anatomical Reconstructions

Objective

To evaluate the outcomes of locked posterior shoulder dislocation with reverse Hill–Sachs lesions in patients treated with anatomical reconstructions.

Methods

Patients who were treated at our institution between January 2016 and June 2020 were retrospectively reviewed. The demographics of the patients including gender, age, occupation, and dominant arm were recorded. Eleven cases from 10 patients qualified in this study. Nine males and one female were included. The mean age of the patients was 44.8 years (range, 33–54 years). Mechanism of injury, duration between injuries and definitive diagnosis, misdiagnosis, size of humeral head impaction, treatment maneuver, and details of operation performed were reviewed. Plain radiographs and computed tomography (CT) scan were taken to determine the size of defects preoperatively and fracture healing during follow‐up. During surgery, the deltopectoral approach was employed. Anatomical reconstruction procedure including reduction, disimpaction, bone grafting, and fixation were sequentially performed. Either cancellous autograft from iliac crest or allograft were used and the fractures were anatomically reduced and stabilized by screws or plates. Visual Analog Scale (VAS) and Constant–Murley score were recorded to determine the functional outcomes preoperatively, at 3 months and 6 months postoperatively, and at the last follow‐up. The range of motion in forward flexion was recorded at 6 months follow‐up postoperatively.

Results

Causes of injuries included epileptic seizure in four cases, fall in three cases, and road traffic accident in three cases. Misdiagnoses occurred in five out of 10 patients. The mean time between injury and definitive treatment among those misdiagnosed was 112 days. The mean size of the impacted reverse Hill–Sachs lesions was 33.95% (range, 19.1%–42.6%). All patients received surgical management with anatomical reconstruction approach, including open reduction, disimpaction, bone grafting, and internal fixation. The mean amount of bleeding during operation was 450 mL. The mean follow‐up period was 22.6 months. Fracture healing was observed by 8 weeks in all cases postoperatively and evidence of bone grafting could not be further detected on CT scan at 6 month during follow‐up. VAS was significantly lower at the last follow‐up (0.68 ± 0.21) in comparison to preoperative scores (4.96 ± 0.97) (P < 0.05). Constant–Murley was improved significantly at the last follow‐up (91.7 ± 8.3) in comparison to that preoperatively (40.6 ± 10.3) (P < 0.05). The mean range of motion in forward flexion was 38.25° ± 9.36° preoperatively and significantly improved to 162.48° ± 12.68° at 6‐month follow‐up (P < 0.05).

Conclusion

The anatomical reconstruction procedure by open reduction and bone augmentation for the treatment of locked posterior shoulder dislocation with reverse Hill–Sachs lesion was promising in both fracture healing and functional outcomes.

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.

Differences in Outcomes Between Anterior and Posterior Shoulder Instability After Arthroscopic Bankart Repair: A Systematic Review and Meta-analysis

Background:

The glenohumeral joint is one of the most frequently dislocated joints in the body, particularly in young, active adults.

Purpose:

To conduct a systematic review and meta-analysis to evaluate and compare outcomes between anterior versus posterior shoulder instability.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed using the PubMed, Cochrane Library, and MEDLINE databases (from inception to September 2019) according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they were published in the English language, contained outcomes after anterior or posterior shoulder instability, had at least 1 year of follow-up, and included arthroscopic soft tissue labral repair of either anterior or posterior instability. Outcomes including return-to-sport (RTS) rate, postoperative instability rate, and pre- and postoperative American Shoulder and Elbow Surgeons (ASES) scores were recorded and analyzed.

Results:

Overall, 39 studies were included (2077 patients; 1716 male patients and 361 female patients). Patients with anterior instability had a mean age of 23.45 ± 5.40 years (range, 11-72 years), while patients with posterior instability had a mean age of 23.08 ± 8.41 years (range, 13-61 years). The percentage of male patients with anterior instability was significantly higher than that of female patients (odds ratio [OR], 1.36; 95% CI, 1.04-1.77; P = .021). Compared with patients with posterior instability, those with anterior instability were significantly more likely to RTS (OR, 2.31; 95% CI, 1.76-3.04; P < .001), and they were significantly more likely to have postoperative instability (OR, 1.53; 95% CI, 1.07-2.23; P = .018). Patients with anterior instability also had significantly higher ASES scores than those with posterior instability (difference in means, 6.74; 95% CI, 4.71-8.77; P < .001). There were no significant differences found in postoperative complications between the anterior group (11 complications; 1.8%) and the posterior group (3 complications; 1.6%) (OR, 1.12; 95% CI, 0.29-6.30; P = .999).

Conclusion:

Patients with anterior shoulder instability had higher RTS rates but were more likely to have postoperative instability compared with posterior instability patients. Overall, male patients were significantly more likely to have anterior shoulder instability, while female patients were significantly more likely to have posterior shoulder instability.

Clinical Trial Registry Use in Orthopaedic Surgery Systematic Reviews

BACKGROUND

Results from systematic reviews and meta-analyses, which have the highest level of evidence (Level I), often drive clinical decision-making and health policy. Often, unpublished trial data are omitted from systematic reviews, raising concerns about the extent of the reliability and validity of results that have been drawn from systematic reviews. We aimed to determine the extent to which systematic review authors include searches of clinical trial registries for unpublished data when conducting systematic reviews in orthopaedic surgery.

METHODS

Systematic reviews and/or meta-analyses were gathered from the top 5 orthopaedic surgery journals based on the h5-index from Google Scholar Metrics. Systematic reviews that had been published in the Cochrane Database of Systematic Reviews, which requires the inclusion of a clinical trial registry search, served as controls. For the primary outcome, each systematic review from the top 5 orthopaedic journals was screened to determine whether the authors of each study searched for unpublished data in clinical trial registries. We then compared the rate of registry searches with those in the control group. For the secondary analysis, a search of ClinicalTrials.gov was performed for unpublished trial data for 100 randomized systematic reviews.

RESULTS

All 38 of the Cochrane systematic reviews (100%) included clinical trial registry searches, while the top 5 orthopaedic journals had only 31 of 480 studies (6.5%) that looked at clinical trial registries. The secondary analysis yielded 59 of 100 systematic review articles (59.0%) that could have included unpublished clinical trial data from ≥1 studies to their sample.

CONCLUSIONS

Systematic reviews that have been published in the top orthopaedic surgery journals seldom included a search for unpublished clinical trial data.

CLINICAL RELEVANCE

The exclusion of clinical trial registry searches potentially contributes to publication bias within the orthopaedic literature. Moving forward, systematic review authors should include clinical trial registry searches for unpublished clinical trial data to provide the most accurate representation of the available evidence for systematic reviews and meta-analyses.

Career Longevity and Performance After Shoulder Instability in National Football League Athletes

PURPOSE

To investigate the career longevity, game utilization, and performance of National Football League (NFL) athletes after glenohumeral instability events treated operatively versus nonoperatively.

METHODS

Using public resources, we identified NFL players who sustained a shoulder instability event from September 2000 to February 2019. Players with prior shoulder instability, without NFL experience before injury, or who did not return to play (RTP) after injury were excluded. Demographic information, utilization (games and seasons), and season approximate value (SAV) statistics were recorded 1 year prior to injury and 3 years after RTP. Statistical analysis compared utilization and the SAV after RTP for athletes managed operatively versus nonoperatively.

RESULTS

We identified 97 NFL players who sustained their first instability event while playing in the NFL, 91 of whom returned to play (93.8%). Quarterbacks were significantly more likely to undergo immediate surgical management compared with players in other positions (P = .023). The final analysis included 58 players managed operatively and 33 managed nonoperatively by the end of the index season. Players treated operatively played in significantly more seasons after RTP during their remaining careers (4.1 ± 2.7 seasons vs 2.8 ± 2.5 seasons, P = .015). There were no differences in games played or started, offensive or defensive snap count percentage, or performance (SAV) before and after injury when compared between cohorts (P > .05). After surgical stabilization, time to RTP (36.62 ± 10.32 weeks vs 5.43 ± 12.33 weeks, P < .05) and time interval before recurrent instability (105.7 ± 100.1 weeks vs 24.7 ± 40.6 weeks, P < .001) were significantly longer than with nonoperative treatment. Additionally, the operative cohort experienced less recurrent instability (27% vs 50%, P = .035).

CONCLUSIONS

Athletes who RTP in the NFL after a shoulder instability injury do so with a similar workload and performance irrespective of surgical or nonsurgical management. Whereas nonoperative treatment is associated with faster RTP, operative management is associated with fewer recurrent instability events, greater time between recurrent instability events, and greater career longevity.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Posterior Glenoid Reconstruction Using a Distal Tibial Allograft

Posterior shoulder instability is increasingly recognized and diagnosed in young athletes. These patients often present with vague shoulder pain rather than the frank instability commonly seen with anterior instability. Three common causes of posterior shoulder instability are congenital retroversion, a single traumatic event, or repetitive microtrauma with erosive effects. The critical determination when deciding on the appropriate treatment of posterior shoulder instability is the presence and degree of glenoid bone loss. In patients without bone loss, arthroscopic procedures have a high success rate with a failure rate of less than 10% and an 89% return-to-sport rate. The determination of the critical amount of bone loss that would permit an arthroscopic procedure is controversial, but recent reports that attempt to quantify the critical bone loss value posteriorly have ranged from 13.5% to 20%. This Technical Note describes our preferred method of open surgical treatment of posterior shoulder instability with posterior glenoid bone loss using an intra-articular distal tibial allograft.

Posterior Shoulder Dislocation with Engaging Reverse Hill-Sachs Lesion: A Retrospective Study of Ten Patients Treated with Arthroscopy or Open Reduction and Stabilization

This study compares two surgical techniques used to treat patients with posterior shoulder dislocation with an engaging reverse Hill–Sachs lesion. We assessed ten patients who were treated at the Surgical Orthopedic and Traumatological Institute (ICOT) of Latina and the Clinic of Orthopedic and Traumatological Surgery of the ASST Sette Laghi of Varese between 2016 and 2019. The patients were divided into two groups: the first comprising six patients who underwent the open surgery McLaughlin procedure as modified by Neer, the second including four patients who underwent the arthroscopic McLaughlin procedure. All patients received postoperative rehabilitation to achieve the best possible functional recovery of the affected shoulder. We then assessed the shoulder range of motion, the pain level, and the impact on quality of life with four tests: the Constant Scale, the Simple Shoulder Test (SST), the OXFORD Scale, and The University of California—Los Angeles (UCLA) Shoulder Scale. The mean scores of the first group were: 81.3 ± 9.8 SD (Constant Scale), 10.8 ± 1.06 SD (SST), 42.5 ± 5.4 SD (Oxford Scale), 30.8 ± 3.02 SD (UCLA Shoulder Scale); we calculated the following mean scores in the second group: 80.25 ± 4.1 SD (Constant Scale), 11.5 ± 0.8 SD (SST), 42 ± 4.06 SD (Oxford Scale), 32 ± 2.9 SD (UCLA Shoulder Scale). We found no significant differences between the two groups.

Risk Factors for Failure of Nonoperative Treatment of Posterior Shoulder Labral Tears on Magnetic Resonance Imaging

INTRODUCTION

There are no reports in the literature describing risk factors for failure of nonoperative treatment of patients with posterior labral tears on magnetic resonance imaging (MRI). The purpose of this study is to identify risk factors for failure of nonoperative treatment in patients with an isolated posterior glenoid labral tear identified on MRI only. Patients with posterior labral tears on MRI who fail to improve with nonoperative treatment likely share a constellation of clinical history, physical exam, and radiographic findings.

METHODS

One hundred and fifty-nine active duty military service members under the age of 40 with a posterior labral tear seen on MRI and who were clinically evaluated by a musculoskeletal trained physician were identified. We retrospectively evaluated their records ensuring a minimum of 2 years follow-up after MRI to identify surgical intervention for the posterior labral tear during this time period. Patients were stratified into two groups, those treated with any combination of nonoperative modalities and those treated with posterior labral repair surgery during the 2 years after the MRI. The electronic medical records were reviewed for clinical presentation and physical exam results. We measured multiple radiographic parameters, including glenoid version, size of the tear, and bone loss on MRI. Qualitative and quantitative data were compared between groups using Fisher's exact test and Student's t-test, respectively. This study was conducted under institutional review board approval.

RESULTS

Of the 157 patients' shoulders in our study, 52% (n = 82) of patients with posterior labral tears underwent nonoperative treatment while 48% (n = 75) underwent surgery. The significant risk factors associated with surgery were a history of a specific injury, primary presenting complaint of instability, patient reported history of subluxation, inability to trust their shoulder with overhead activity, decreased strength with weight lifting, positive posterior load/shift exam, positive anterior apprehension, increased osseous glenoid retroversion, increased humeral head subluxation ratio, and anterior labral height (P < 0.05). Patients with a chief complaint of pain were much more likely to succeed with nonoperative treatment while those with instability underwent surgery more often. Ten (12.5%) of the surgical procedures included an anterior and posterior labral repair/stabilization procedure.

CONCLUSION

Patients with an MRI confirmed posterior labral tear, which present with subjective complaints and physical exam maneuvers consistent with instability, appear less likely to be treated nonoperatively. Increased glenoid retroversion and posterior humeral head subluxation may also predispose patients toward surgical treatment. Additionally, posterior labral tears may extend into the anterior labrum more frequently than is recognized on MRI.

Acceptable Long-Term Outcomes of Arthroscopic Bone Grafting for Recurrent Posterior Shoulder Instability: Minimum Follow-Up of 5 Years

PURPOSE

To examine the long-term clinical outcome associated with arthroscopically placed autologous iliac crest bone graft (ICBG) for recurrent posterior shoulder instability.

METHODS

From January 2008 to December 2013, patients treated with posterior ICBG and a minimum follow-up of 5 years were included. Clinical outcome of patients operated with a posterior ICBG was analyzed with multiple patient-reported outcome measures included Constant (CS), American Shoulder and Elbow Surgeons (ASES), Walch-Duplay, and Rowe scores, shoulder subjective value, and pain visual analog score. Patient satisfaction was assessed by asking the patients their overall level of satisfaction at last follow-up on a 1 to 10 scale.

RESULTS

In total, 18 patients (19 shoulders) were included. At a mean follow-up of 7.3 years (range, 5-10 years), patients had significant improvements in their mean CS from 63 (standard deviation [SD] 18) to 80 (SD 18; P = .005), ASES from 57 (SD 18) to 81 (SD 18; P = .003), Walch-Duplay from 34 (SD 31) to 79 (SD 22; P < .001), and Rowe score from 37 (SD 23) to 79 (SD 24; P < .001). Pain level decreased from 5.6 (SD 2.5) preoperative to 2.3 (SD 2.3; P < .001) and shoulder subjective value improved 58 (SD 20) to 76 (SD 24; P = .002). Global satisfaction with the procedure was 8.4 (SD 2.1). Clinical significance was met or exceeded by 84% for CS and 89% of the patients for ASES and 95% met or exceeded satisfaction threshold for CS. There were 7 shoulders (37%) reoperated for symptomatic screw irritation.

CONCLUSIONS

This series reporting on the long-term follow-up after arthroscopic posterior ICBG for recurrent posterior shoulder instability demonstrates, despite a high number of reoperations for symptomatic screw irritation, its effectiveness with acceptable clinical outcomes and satisfied patients.

LEVEL OF EVIDENCE

IV, therapeutic case series.