The Nonoperative Instability Severity Index Score: Is It Predictive in a Larger Shoulder Instability Population at Long-Term Follow-Up?

Comparing Recurrence Rates and the Cost-Effectiveness of Arthroscopic Labral Repair and Nonoperative Management for Primary Anterior Shoulder Dislocations in Young Patients: A Decision-Analytic Markov Model-Based Analysis

BACKGROUND

Value-based decision-making regarding nonoperative management versus early surgical stabilization for first-time anterior shoulder instability (ASI) events remains understudied.

PURPOSE

To perform (1) a systematic review of the current literature and (2) a Markov model-based cost-effectiveness analysis comparing an initial trial of nonoperative management to arthroscopic Bankart repair (ABR) for first-time ASI.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 3.

METHODS

A Markov chain Monte Carlo probabilistic model was developed to evaluate the outcomes and costs of 1000 simulated patients (mean age, 20 years; range, 12-26 years) with first-time ASI undergoing nonoperative management versus ABR. Utility values, recurrence rates, and transition probabilities were derived from the published literature. Costs were determined based on the typical patient undergoing each treatment strategy at the authors' institution. Outcome measures included costs, quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER).

RESULTS

The Markov model with Monte Carlo microsimulation demonstrated mean (± standard deviation) 10-year costs for nonoperative management and ABR of $38,649 ± $10,521 and $43,052 ± $9352, respectively. Total QALYs acquired over the 10-year time horizon were 7.67 ± 0.43 and 8.44 ± 0.46 for nonoperative management and ABR, respectively. The ICER comparing ABR with nonoperative management was found to be just $5725/QALY, which falls substantially below the $50,000 willingness-to-pay (WTP) threshold. The mean numbers of recurrences were 2.55 ± 0.31 and 1.17 ± 0.18 for patients initially assigned to the nonoperative and ABR treatment groups, respectively. Of 1000 samples run over 1000 trials, ABR was the optimal strategy in 98.7% of cases, with nonoperative management the optimal strategy in 1.3% of cases.

CONCLUSION

ABR reduces the risk for recurrent dislocations and is more cost-effective despite higher upfront costs when compared with nonoperative management for first-time ASI in the young patient. While all these factors are important to consider in surgical decision-making, ultimate treatment decisions should be made on an individual basis and occur through a shared decision-making process.

Predicting recurrence of instability after a primary traumatic anterior shoulder dislocation

Aims

The risk factors for recurrent instability (RI) following a primary traumatic anterior shoulder dislocation (PTASD) remain unclear. In this study, we aimed to determine the rate of RI in a large cohort of patients managed nonoperatively after PTASD and to develop a clinical prediction model.

Methods

A total of 1,293 patients with PTASD managed nonoperatively were identified from a trauma database (mean age 23.3 years (15 to 35); 14.3% female). We assessed the prevalence of RI, and used multivariate regression modelling to evaluate which demographic- and injury-related factors were independently predictive for its occurrence.

Results

The overall rate of RI at a mean follow-up of 34.4 months (SD 47.0) was 62.8% (n = 812), with 81.0% (n = 658) experiencing their first recurrence within two years of PTASD. The median time for recurrence was 9.8 months (IQR 3.9 to 19.4). Independent predictors increasing risk of RI included male sex (p < 0.001), younger age at PTASD (p < 0.001), participation in contact sport (p < 0.001), and the presence of a bony Bankart (BB) lesion (p = 0.028). Greater tuberosity fracture (GTF) was protective (p < 0.001). However, the discriminative ability of the resulting predictive model for two-year risk of RI was poor (area under the curve (AUC) 0.672). A subset analysis excluding identifiable radiological predictors of BB and GTF worsened the predictive ability (AUC 0.646).

Conclusion

This study clarifies the prevalence and risk factors for RI following PTASD in a large, unselected patient cohort. Although these data permitted the development of a predictive tool for RI, its discriminative ability was poor. Predicting RI remains challenging, and as-yet-undetermined risk factors may be important in determining the risk.

Editorial Commentary: Urgency Toward Arthroscopic Bankart Repair Is Essential for Anterior Shoulder Dislocation: You Don't Have to Fix After the First Dislocation, but Definitely Before the Second!

While still hotly debated, primary arthroscopic management of the first-time anterior shoulder dislocation has an extensive list of known benefits: lower overall health care costs, improved patient-reported outcomes, a vast reduction in secondary instability, and higher quality-of-life measures. Yet, despite these meaningful contributions to health care quality, we continue to bypass the predictable success of an acute arthroscopic Bankart repair in order to tempt fate with "a trial" of nonoperative care for our young, high-risk collision athletes. Whether for the in-season athlete, the "early responder" with limited apprehension, subluxations with spontaneous reduction, or those stoically committed to nonsurgical care, we as physicians are often complicit in this shared risk taking and ceremonial weighing of the risks and benefits for treatment options after primary shoulder instability. Even just 1 additional episode of instability recurrence can double (or triple) the rate of glenohumeral bone loss. Furthermore, subsequent anterior shoulder instability compromises subjective shoulder function, heightens risk of secondary recurrence and/or revision, and increases the likelihood of requiring more advanced surgical management, such as with a Latarjet or other anterior bone block procedure. We must maintain a sense of urgency toward surgical treatment, particularly in young, high-demand athletes with persistent instability. To parrot the wisdom of our shoulder mentors, hear my humble plea: you don't have to fix the shoulder after the first anterior dislocation, but you should definitely do it before the second!

Editorial Commentary: The Nonoperative Instability Severity Index Score Can, in Part, Help to Predict Failure After Nonoperative Management of Anterior Shoulder Instability: Fix Them All Versus Wait and See?

The optimal management of anterior shoulder instability remains a heated topic of debate, particularly after first-time shoulder dislocation. From expedited rehabilitation to arthroscopic Bankart repair and Latarjet coracoid transfer, the shoulder community has staunchly defended its approach with carefully tailored data describing patient satisfaction, instability recurrence, revision surgery, and timeline to return to play or preinjury activity. However, not all patients require surgical stabilization, and a "wait-and-see" approach can often result in favorable outcome. The Nonoperative Instability Severity Index Score has been proposed as a unique tool to stratify risk for failure among athletes after an anterior shoulder instability event. While not a standalone tool for predicting further shoulder dislocation in a broader athletic population, the Nonoperative Instability Severity Index Score reflects a movement toward personalized medicine, where clinical decision making is executed on the individual level based on unique risk factors and circumstances.