Current Treatment Options for Glenohumeral Instability and Bone Loss

Open Bone Augmentation Solutions for the Failed Shoulder Stabilization

Utilizing fresh distal tibia allograft in anterior glenoid reconstruction has emerged as a highly advantageous approach in addressing instances of failed anterior shoulder stabilization with glenoid bone loss. This procedure offers several benefits, including the absence of donor-site morbidity, restoration of significant glenoid defects, reestablishment of joint congruity with the humeral head, restoration of glenoid biomechanics, and the addition of cartilage to the glenoid. Furthermore, it provides a robust and reliable alternative for managing failed stabilization procedures, leading to improved clinical outcomes and a high graft healing rate, while maintaining a low occurrence of recurrent instability.

The Perfect Circle Technique Shows Poor Inter-rater Reliability in Measuring Anterior Glenoid Bone Loss on Magnetic Resonance Imaging

Purpose

To evaluate the reliability of the perfect circle methodology for measurement of glenoid bone loss in patients with anterior glenohumeral instability.

Methods

We performed a chart review of retrospectively collected patients who underwent isolated arthroscopic anterior labral repair between January 1 and June 30, 2021, using our institution's electronic medical records. The inclusion criteria included isolated anterior shoulder instability with anterior labral repair and corroborated tears on magnetic resonance imaging. A total of 9 raters, either sports or shoulder and elbow fellowship-trained orthopaedic surgeons, each evaluated the affected shoulder magnetic resonance imaging scans twice, with a minimum of 2 weeks between measurements. Measurements followed the "perfect circle" technique and included projected anterior-to-posterior glenoid diameter, amount of posterior bone loss, and percentage of posterior bone loss. Intrarater reliability and inter-rater reliability were then determined by calculating intraclass correlation coefficients (ICCs).

Results

Ten consecutive patients meeting the selection criteria were chosen for inclusion in this analysis. Average estimated bone loss for the cohort was 2.45 mm, and the mean estimated glenoid diameter of the involved shoulder was 28.82 mm. The average percentage of bone loss measured 8.54%. The ICC for interobserver reliability was 0.55 for the perfect circle diameter and 0.17 for the anterior bone loss measurement (poorly to moderately reliable). The ICC for intraobserver reliability was 0.69 for the perfect circle diameter and 0.71 for anterior bone loss (moderately reliable).

Conclusions

The perfect circle technique for estimating anterior glenoid bone loss on magnetic resonance imaging was found to have moderate intrarater reliability; however, reliability between observers was found to be moderate to poor.

Level of Evidence

Level IV, diagnostic case series.

The Perfect-Circle Technique Demonstrates Poor Inter-Rater Reliability in Measuring Posterior Glenoid Bone Loss on Magnetic Resonance Imaging

Purpose

To evaluate the reliability of the "perfect-circle" methodology for measurement of glenoid bone loss with magnetic resonance imaging (MRI) in patients with posterior glenohumeral instability.

Methods

A prospective chart review was performed on patients who underwent isolated arthroscopic posterior labral repairs in our institution's electronic medical records between January 1, 2021, and June 30, 2021. Inclusion criteria included isolated posterior shoulder instability with posterior labral repair and corroborated tears on MRI. A total of 9 raters, either sports or shoulder and elbow fellowship-trained orthopaedic surgeons, each evaluated the affected shoulder MRI scans twice, at over 2 weeks apart. Measurements followed the "perfect-circle" technique and included projected anterior-to-posterior (AP) glenoid diameter, amount of posterior bone loss, and percentage of posterior bone loss.

Results

Ten consecutive patients between the ages of 17 and 46 years with diagnosed posterior glenohumeral instability were selected. The average age was 28 ± 10 years, and 60% of patients were male. The patient's dominant arm was affected in 40%, and 50% of cases involved the right shoulder. The average glenoid diameter was 29.62 ± 3.69 mm, and the average measured bone loss was 2.8 ± 1.74 mm. The average percent posterior glenoid bone loss was 9.41 ± 5.78%. The inter-rater reliability was poor for the AP diameter and for the posterior glenoid bone loss with intraclass correlation coefficients at 0.30 (0.12-0.62) and 0.22 (0.07-0.54) respectively. The intrarater reliability was poor for AP diameter and moderate for posterior glenoid bone loss, with intraclass correlation coefficients at 0.41 (0.22-0.57) and 0.50 (0.33-0.64), respectively.

Conclusions

Using the "perfect-circle" technique for evaluating posterior glenohumeral bone loss has poor-to-moderate inter- and intrarater reliability from MRI.

Level of Evidence

Level IV, prospective diagnostic study.

Outcomes of Shoulder Instability Surgery in Competitive Wrestlers: Outcomes, Reoperations, and Return to Play at 5 Years' Mean Follow-up

BACKGROUND

Wrestling is a physically demanding sport with young athletes prone to traumatic shoulder instability and a paucity of data evaluating the results of shoulder instability surgery (SIS).

PURPOSE

To assess reoperation rates, patient-reported outcomes, and return to wrestling (RTW) after SIS in a cohort of competitive wrestlers.

STUDY DESIGN

Case series; Level of evidence, 3.

METHODS

All competitive wrestlers with a history of shoulder instability and subsequent surgery at a single institution between 1996 and 2020 were identified. All directions of shoulder instability (anterior shoulder instability [ASI], posterior shoulder instability [PSI], and traumatic multidirectional shoulder instability [TMDI]) were analyzed. Exclusions included revision SIS and <2 years of follow-up. Athletes were contacted for determination of complications, RTW, and Western Ontario Shoulder Instability Index scores.

RESULTS

Ultimately, 104 wrestlers were included with a mean age at initial instability of 16.9 years (range, 12.0-22.7 years), mean age at surgery of 18.9 years (range, 14.0-29.0 years), and a mean follow-up of 5.2 years (range, 2.0-22.0 years). A total of 58 (55.8%) wrestlers were evaluated after a single shoulder instability event, while 46 (44.2%) sustained multiple events before evaluation. ASI was the most common direction (n = 79; 76.0%), followed by PSI (n = 14; 13.5%) and TMDI (n = 11; 10.6%). Surgical treatment was most commonly an arthroscopic soft tissue stabilization (n = 88; 84.6%), with open soft tissue repair (n = 13; 12.5%) and open bony augmentation (n = 3; 2.9%) performed less frequently. RTW occurred in 57.3% of wrestlers at a mean of 9.8 months. Recurrent instability was the most common complication, occurring in 18 (17.3%) wrestlers. Revision SIS was performed in 15 (14.4%) wrestlers. Across the entire cohort, survivorship rates free from recurrent instability and revision surgery were 90.4% and 92.5% at 2 years, 71.9% and 70.7% at 5 years, and 71.9% and 66.5% at 10 years, respectively. Preoperative recurrent instability was an independent risk factor for postoperative recurrent instability (hazard ratio, 3.8; 95% CI, 1.33-11.03; P = .012).

CONCLUSION

Competitive wrestlers with multiple dislocations before initial clinical evaluation were 3.8 times more likely to experience postoperative recurrent instability. Patients should be counseled that despite SIS, only 57.3% returned to wrestling after surgery.

Utility of Talus Osteochondral Allograft Augmentation for Varying Hill-Sachs Lesion Sizes: A Cadaveric Study

Background

Humeral head reconstruction with fresh osteochondral allografts (OCA) serves as a potential treatment option for anatomic reconstruction. More specifically, talus OCA is a promising graft source because of its high congruency with a dense cartilaginous surface.

Purpose

To analyze the surface geometry of the talus OCA plug augmentation for the management of shoulder instability with varying sizes of Hill-Sachs lesions (HSLs).

Study Design

Controlled laboratory study.

Methods

Seven fresh-frozen cadaveric shoulders were tested in this study. The humeral heads were analyzed using actual patients' computed tomography scans. Surface laser scan analysis was performed on 7 testing states: (1) native state; (2) small HSL; (3) talus OCA augmentation for small HSL; (4) medium HSL; (5) talus OCA augmentation for medium HSL; (6) large HSL; and (7) talus OCA augmentation for large HSL. OCA plugs were harvested from the talus allograft and placed in the most medial and superior aspect of each HSL lesion. Surface congruency was calculated as the mean absolute error and the root mean squared error in the distance. A 1-way repeated-measures analysis of variance was performed to evaluate the effects of the difference in the HSL size and associated talus OCA plugs on surface congruency and the HSL surface area.

Results

The surface area analysis of the humeral head with the large (1469 ± 75 mm2), medium (1391 ± 81 mm2), and small (1230 ± 54 mm2) HSLs exhibited significantly higher surface areas than the native state (1007 ± 88 mm2; P < .001 for all sizes). The native state exhibited significantly lower surface areas as compared with after talus OCA augmentation for large HSLs (1235 ± 63 mm2; P < .001) but not for small or medium HSLs. Talus OCA augmentation yielded improved surface areas and congruency after treatment in small, medium, and large HSLs (P < .001).

Conclusion

Talus OCA plug augmentation restored surface area and congruency across all tested HSLs, and the surface area was best improved with the most common HSLs-small and medium.

Clinical Relevance

Talus OCA plugs may provide a viable option for restoring congruity of the shoulder in patients with recurrent anterior glenohumeral instability and an HSL.

Arthroscopic Xenograft With Cerclage Fixation: A Method for Glenoid Bone Loss Reconstruction With Cerclage Fixation Using a Specific Posterior Guide

Large glenoid bone defects are closely associated with high failure rates after arthroscopic Bankart repair in chronic anterior shoulder instability; therefore nowadays the glenoid bone grafting reconstruction procedure is strictly recommended. On the contrary, the optimal grafting procedure is still controversial because there is considerable concern about the resorption rate of allografts, donor site morbidity of the autografts, and sequelae caused by the use of metal fixation devices in proximity of the shoulder joint. We describe an all-arthroscopic technique for anatomic reconstruction of the glenoid that uses a previously shaped xenograft assembled with a metal-free fixation device using 2 ultra-high-strength sutures (FiberTape Cerclage System; Arthrex, Naples, FL), using a specific posterior guide (Arthrex, Naples, FL) in combination with upper third subscapularis augmentation.

Prospective Evaluation of Posterior Glenoid Bone Loss After First-time and Recurrent Posterior Glenohumeral Instability Events

BACKGROUND

Although posterior glenohumeral instability is becoming an increasingly recognized cause of shoulder pain, the role of posterior glenoid bone loss on outcomes remains incompletely understood.

PURPOSES

To prospectively determine the amount of bone loss associated with posterior instability events and to determine predisposing factors based on preinstability imaging.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 1428 shoulders were evaluated prospectively for ≥4 years. At baseline, a subjective history of shoulder instability was ascertained for each patient, and bilateral noncontrast magnetic resonance imaging (MRI) scans of the shoulders were obtained regardless of any reported history of shoulder instability. The cohort was prospectively followed during the study period, and those who were diagnosed with posterior glenohumeral instability were identified. Postinjury MRI scans were obtained and compared with the screening MRI scans. Glenoid version, perfect-circle-based bone loss was measured for each patient's pre- and postinjury MRI scans using previously described methods.

RESULTS

Of the 1428 shoulders that were prospectively followed, 10 shoulders sustained a first-time posterior instability event and 3 shoulders sustained a recurrent posterior instability event. At baseline, 11 of 13 shoulders had some amount of glenoid dysplasia and/or bone loss. The change in glenoid bone loss was 5.4% along the axis of greatest loss (95% CI, 3.8%-7.0%; P = .009), 4.4% at the glenoid equator (95% CI, 2.7%-6.2%; P = .016), and 4.2% of total glenoid area (95% CI, 2.9%-5.3%; P = .002). Recurrent glenoid instability was associated with a greater amount of absolute bone loss along the axis of greatest loss compared with first-time instability (recurrent: 16.8% ± 1.1%; 95% CI, 14.6%-18.9%; first-time: 10.0% ± 1.5%; 95% CI, 7.0%-13.0%; P = .005). Baseline glenoid retroversion ≥10° was associated with a significantly greater percentage of bone loss along the axis of greatest loss (≥10° of retroversion: 13.5% ± 2.0%; 95% CI, 9.6%-17.4%; <10° of retroversion: 8.5% ± 0.8%; 95% CI, 7.0%-10.0%; P = .045).

CONCLUSIONS

Posterior glenohumeral instability events were associated with glenoid bone loss of 5%. The amount of glenoid bone loss after a recurrent posterior glenohumeral instability event was greater than that after first-time instability. Glenoid retroversion ≥10° was associated with a greater amount of posterior glenoid bone loss after a posterior instability event.

The Latarjet procedure in competitive athletes younger than 20 years old with a significant glenoid bone loss

PURPOSE

To analyze return to sports, functional outcomes, and complications following the Latarjet procedure in competitive athletes younger than 20 years old with a significant glenoid bone loss.

METHODS

Between 2010 and 2017, 60 competitive athletes younger than 20 years old with a significant glenoid bone loss were operated with the Latarjet procedure. Return to sports, range of motion, and the Rowe and the Athletic Shoulder Outcome Scoring System score were used to assess functional outcomes. Complications and bone consolidation were also evaluated.

RESULTS

The mean follow-up was 58 months and the mean age was 16.3 years. Overall, 93% were able to return to sports and 84% returned at the same level. The Rowe and Athletic Shoulder Outcome Scoring System scores showed statistical improvement after operation (P <  .001). The total complication rate was 22% and the revision rate was 1.6%. The recurrence rate was 3.3%. The bone block healed in 93% of the cases.

CONCLUSIONS

In competitive athletes younger than 20 years old with a significant glenoid bone loss, the Latarjet procedure resulted in excellent functional outcomes, with most of the patients returning to sports and at the same level they had before injury with a low rate of recurrences. However, this procedure is associated with a significant rate of complications and should preferably be performed by experienced surgeons.

Return to sport following Latarjet glenoid reconstruction for anterior shoulder instability

BACKGROUND

Latarjet coracoid transfer reconstruction is the gold standard for the treatment of recurrent shoulder instability with anterior-inferior glenoid bone loss, and return to sport is often a primary outcome of interest in this patient population. The purpose of this study was to determine the rate of return to sport in patients undergoing the Latarjet procedure and variables that are associated with a higher likelihood of a successful return to sport.

METHODS

A prospectively maintained institutional registry was retrospectively queried between August 2012 and August 2016 for all patients who underwent the Latarjet procedure. Patients were contacted electronically and via telephone to administer a previously validated and standardized return-to-sport survey. Patients self-reported return to sport, varying sports participation, recurrence of instability, and time to return to sport. Multivariate analysis was performed to determine variables associated with each outcome.

RESULTS

Of 83 patients, 66 (75.3%) were available for final follow-up, of whom 60 participated in sports prior to surgery and were eligible for inclusion. The average follow-up period was 53.8 ± 11.8 months. The average age at surgery was 26.7 ± 11.3 years, and the average body mass index was 26.2 ± 4.0 kg/m². There were 54 patients (90%) who were able to return to sport at an average of 8.6 ± 4.1 months following surgery. In total, 36 patients (60%) were able to return to sport at the same level or a better level of intensity, 19 of 28 patients (67.9%) were able to return to throwing sports without difficulty, and 31 of 60 patients (51.7%) reported that their shoulder was a hindrance to some activity. An increased likelihood of returning to sport was associated with increased body mass index (P = .016), male sex (P = .028), and decreased humeral bone loss volume (P = .034). An increased likelihood of returning to sport at the same level or a better level of intensity was associated with reduced humeral bone loss volume (P = .026). Recurrent instability was associated with humeral bone loss (P = .038).

CONCLUSION

Although a large majority of patients were able to return to sport following the Latarjet procedure, some patients experienced limitation with throwing and return to sport at the preinjury level. Greater humeral bone loss was associated with inferior outcomes. These findings should be discussed with patients in the preoperative setting to manage expectations appropriately.

Arthroscopic bone block metal-free fixation for anterior shoulder instability. Short-term functional and radiological outcomes

INTRODUCTION

Anterior glenohumeral bone loss reconstruction reduces failure rates after soft tissue surgery in patients with large glenoid bone defects. Multiple bone block techniques have been described, most with metal hardware fixation. The objective of this study is to evaluate the safety, as well as the short-term functional and radiological results of an arthroscopic bone block metal-free fixation or bone block cerclage.

MATERIAL AND METHODS

Retrospective study of patients with glenohumeral instability and>15% glenoid bone loss operated during 2019 with follow-up of at least 12 months. Radiography and computerized tomography studies were performed. Functional outcomes were evaluated before and after surgery with the Western Ontario Shoulder Instability Index and Rowe score.

RESULTS

A total of 21 patients with a median age of 30.6 (SD 7.1) were included. All showed radiographic consolidation at 3 months follow-up. A percentage of 90.4 of bone grafts presented osteolysis at peripherical areas and 95.2% revealed consolidation in the areas with contact to the glenoid. The median glenoid estimated surface went from 79.3% before surgery to 98.4% at 12 months. Functional scores were statically significant (P<.001) for Western Ontario Shoulder Instability Index (35.6-86.9) and Rowe score (25.2 to 96.4). No serious complications were reported.

CONCLUSION

The bone block cerclage is a safe, metal-free technique that achieves total consolidation of the bone graft and favorable functional and radiological outcomes at 12 months follow-up.

Evaluation and Management of Glenohumeral Instability With Associated Bone Loss: An Expert Consensus Statement Using the Modified Delphi Technique

PURPOSE

To establish an international expert consensus, using the modified Delphi technique, on the evaluation and management of glenohumeral instability with associated bone loss.

METHODS

A working group of 6 individuals generated a list of statements related to history and physical examination, imaging and specialized diagnostic tests, bone loss quantification and classification, treatment outcomes and complications, and rehabilitation for the management of glenohumeral instability associated with bone loss to form the basis of an initial survey for rating by a group of experts. The expert group (composed of 22 high-volume glenohumeral instability experts) was surveyed on 3 occasions to establish a consensus on the statements. Items with over 70% agreement and less than 10% disagreement achieved consensus.

RESULTS

After a total of 3 rounds, 31 statements achieved consensus. Eighty-six percent of the experts agreed that a history of multiple dislocations and failed soft-tissue surgery should raise suspicion about the possibility of an associated bone deficit. Ninety-five percent of the experts agreed that 3-dimensional (3D) computed tomography (CT) is the most accurate diagnostic method to evaluate and quantify bone loss. Eighty-six percent of the experts agreed that any of the available methods to measure glenoid bone deficiency is adequate; however, 91% of the experts thought that an en face view of the glenoid using 3D CT provides the most accurate method. Ninety-five percent of the experts agreed that Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Ninety percent of the experts agreed that in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed and any of the available options is valid. There was no consensus among experts on how Hill-Sachs injuries should be managed or on how postoperative rehabilitation should be carried out.

CONCLUSIONS

The essential statements on which the experts reached consensus included the following: A history of multiple dislocations and failed soft-tissue surgery should make surgeons consider the possibility of an associated bone deficit. Three-dimensional CT is the most accurate diagnostic method to evaluate and quantify bone loss. Although any of the available methods to measure glenoid bone deficiency is adequate, an en face view of the glenoid using 3D CT provides the most accurate method. Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Finally, in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed.

LEVEL OF EVIDENCE

Level V, consensus statement.

Editorial Commentary: Delphi Expert Consensus Clarifies Evidence-Based Medicine for Shoulder Instability and Bone Loss

Anterior glenohumeral instability with glenoid bone loss is a difficult problem and often requires open procedures with bone block augmentation. The current evidence suggests glenoid bone loss of 20% or more as a cutoff value indicating augmentation. Expert consensus-based techniques, such as the Delphi, clarify evidence-based medicine and allow pooling of expert opinion in a scientific fashion. These methods suggest that 3-dimensional computed tomography should be used to evaluate bone loss, previous dislocations, or failed soft-tissue surgery; Hill-Sachs lesions are poorly quantified by standard imaging; and, in cases with a bone deficit of >20%, glenoid bone graft should be considered. No consensus was reached regarding glenoid track evaluation, magnetic resonance imaging for evaluation of bone loss, safety of arthroscopic Latarjet, remplissage use for Hill-Sachs lesions of less than 30%, indications for a shoulder sling for 4 to 6 weeks after surgery, or postoperative rehabilitation timing and range-of-motion protocols.

Latarjet Cerclage: The All-Arthroscopic Metal-Free Fixation

The Bristow-Latarjet procedure has been one of the most recognized procedures for the treatment of recurrent shoulder dislocation with anterior glenoid bone loss, revision surgery after failed Bankart repair, contact and collision sport injuries, and patients with a high risk of recurrence. Open and arthroscopic approaches have recently shown similar outcomes by several authors. However, complications related to metal implants, despite being low, are still a matter of concern. We describe an all-arthroscopic Latarjet technique with a metal-free fixation method using 2 ultra-high-strength sutures, creating a cerclage construct through 2.4mm glenoid and coracoid tunnels with a final capsulolabral complex reconstruction.

High Rate of Return to Sports and Low Recurrences With the Latarjet Procedure in High-Risk Competitive Athletes With Glenohumeral Instability and a Glenoid Bone Loss <20

Purpose

To analyze return to sports, functional outcomes, and complications following the Latarjet procedure in competitive athletes with anterior glenohumeral instability and glenoid bone loss <20%.

Methods

All the included patients were operated between 2010 and 2016. The inclusion criteria were competitive athletes with anterior glenohumeral instability, a glenoid bone defect <20% who participated in contact sports, forced overhead sports, or had a previous failed Bankart repair and had a minimum 2 years’ follow-up. Return to sports, range of motion (ROM), the Rowe score, and the Athletic Shoulder Outcome Scoring System score were used to assess functional outcomes. Complications and bone consolidation were also evaluated.

Results

A total of 65 athletes were included in the study. The mean follow-up was 53 months (±13), and the mean age was 23.9 years (range, 16-31 years). Overall, 94% were able to return to sports and 84% returned at the same level. No significant difference in shoulder ROM was found between preoperative and postoperative results. The Rowe and Athletic Shoulder Outcome Scoring System scores showed statistical improvement after operation (P < .001). No significant difference in shoulder ROM and functional scores was found between primary and revision cases. The total complication rate was 11% and the revision rate was 1.5% The recurrence rate was 4.6%. The bone block healed in 95% of the cases.

Conclusions

In high-risk competitive athletes with anterior glenohumeral instability and glenoid bone loss <20%, the Latarjet procedure resulted in excellent functional outcomes, with most of the patients returning to sports and at the same level they had before injury with a low rate of recurrences

Level of Evidence

Therapeutic case series; Level of evidence, IV

The novel arthroscopic subscapular sling procedure grants better stability than an arthroscopic Bankart repair in a cadaveric study

PURPOSE

This novel arthroscopic subscapular sling procedure stabilizes the shoulder using a semitendinosus graft to create a sling around the subscapular tendon, which provides both static and dynamic stability. The aim of the study was to evaluate the biomechanical stability of the subscapular sling procedure in human cadaveric shoulders. The hypothesis was that the sling offers an equal stabilizing effect and range of motion compared to an arthroscopic Bankart repair.

METHODS

Sixteen shoulders were investigated using an industrial robot-based testing platform and four different conditions: the physiologically intact shoulder, after creating a Bankart lesion, after arthroscopic Bankart repair, and finally after applying the subscapular sling procedure using a semitendinosus tendon graft. Joint translation and external rotation were evaluated for each condition.

RESULTS

The results show improved stability in the shoulders with the subscapular sling. The robot testing revealed a significant reduction in translation in anterior and anterior-inferior directions compared to the arthroscopic Bankart repair. None of the shoulders were dislocated by forced manual abduction and external rotation. No difficulties were encountered in performing the arthroscopic subscapular sling procedure. Thorough postoperative anatomical dissection showed no alterations to structures at risk.

CONCLUSION

The biomechanical results show increased stability with the use of the subscapular sling method.

Management of bone loss in recurrent traumatic anterior shoulder instability: a survey of North American surgeons

Background

Management of bone loss in recurrent traumatic anterior shoulder instability remains a topic of debate and controversy in the orthopedic community. The purpose of this study was to survey members of 4 North American orthopedic surgeon associations to assess management trends for bone loss in recurrent anterior shoulder instability.

Methods

An online survey was distributed to all members of the American Shoulder and Elbow Surgeons, American Orthopaedic Society for Sports Medicine, and Canadian Orthopaedic Association and to fellow members of the Arthroscopy Association of North America. The survey comprised 3 sections assessing the demographic characteristics of survey respondents, the influence of prognostic factors on surgical decision making, and the operative management of 12 clinical case scenarios of varying bone loss that may be encountered in clinical practice.

Results

A total of 150 survey responses were returned. The age of the patient and quantity of bone loss were consistently considered important prognostic criteria. However, little consensus was reached for critical thresholds of bone loss and how this affected the timing (ie, primary or revision surgery) and type of bony augmentation procedure to be performed once a critical threshold was reached, especially in the context of critical humeral and bipolar bone loss.

Conclusions

Consistent trends were found for the management of recurrent anterior shoulder instability in cases in which no bone loss existed and when isolated critical glenoid bone loss was present. However, inconsistencies were observed when isolated critical humeral bone loss and bipolar bone loss were present.

Prospective Evaluation of Glenoid Bone Loss After First-time and Recurrent Anterior Glenohumeral Instability Events

BACKGROUND

Determining the amount of glenoid bone loss in patients after anterior glenohumeral instability events is critical to guiding appropriate treatment. One of the challenges in treating the shoulder instability of young athletes is the absence of clear data showing the effect of each event.

PURPOSE

To prospectively determine the amount of bone loss associated with a single instability event in the setting of first-time and recurrent instability.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The authors conducted a prospective cohort study of 714 athletes surveilled for 4 years. Baseline assessment included a subjective history of shoulder instability. Bilateral noncontrast shoulder magnetic resonance imaging (MRI) was obtained for all participants with and without a history of previous shoulder instability. The cohort was prospectively followed during the study period, and those who sustained an anterior glenohumeral instability event were identified. Postinjury MRI with contrast was obtained and compared with the screening MRI. Glenoid width was measured for each patient's pre- and postinjury MRI. The projected total glenoid bone loss was calculated and compared for patients with a history of shoulder instability.

RESULTS

Of the 714 athletes (1428 shoulders) who were prospectively followed during the 4-year period, 22 athletes (23 shoulders) sustained a first-time anterior instability event (5 dislocations, 18 subluxations), and 6 athletes (6 shoulders) with a history of instability sustained a recurrent anterior instability event (1 dislocation, 5 subluxations). On average, there was statistically significant glenoid bone loss (1.84 ± 1.47 mm) after a single instability event ( P < .001), equivalent to 6.8% (95% CI, 4.46%-9.04%; range, 0.71%-17.6%) of the glenoid width. After a first-time instability event, 12 shoulders (52%) demonstrated glenoid bone loss ≥5% and 4 shoulders, ≥13.5%; no shoulders had ≥20% glenoid bone loss. Preexisting glenoid bone loss among patients with a history of instability was 10.2% (95% CI, 1.96%-18.35%; range, 0.6%-21.0%). This bone loss increased to 22.8% (95% CI, 20.53%-25.15%; range, 21.2%-26.0%) after additional instability ( P = .0117). All 6 shoulders with recurrent instability had ≥20% glenoid bone loss.

CONCLUSION

Glenoid bone loss of 6.8% was observed after a first-time anterior instability event. In the setting of recurrent instability, the total calculated glenoid bone loss was 22.8%, with a high prevalence of bony Bankart lesions (5 of 6). The findings of this study support early stabilization of young active patients after a first-time anterior glenohumeral instability event.