Distal Tibial Allograft for the Treatment of Shoulder Instability Provides Excellent Results With Low Rates of Recurrent Instability: A Systematic Review of Clinical and Biomechanical Studies

Abstract

Purpose: To systematically review the literature to evaluate the clinical and biomechanical results of distal tibial allograft (DTA) for shoulder instability.

Methods: A literature search of the MEDLINE, Embase, and Cochrane Library databases was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Clinical and biomechanical studies reporting the results of DTA for shoulder instability were included. Qualitative and quantitative data were evaluated.

Results: A total of 9 clinical and 7 biomechanical studies were included. A total of 341 patients with an average age of 25.5 to 31 years were included in the clinical analysis. Cohorts ranged from 61.9% to 100% male, and average glenoid bone loss ranged from 20% to 33%. The recurrent dislocation rate after DTA procedures ranged from 0% to 2.0%. Mean preoperative Single Assessment Numeric Evaluation scores ranged from 32.2 to 50, whereas postoperative scores ranged from 85 to 91. Mean preoperative American Shoulder and Elbow Surgeons scores ranged from 40 to 63, whereas postoperative scores ranged from 90.5 to 92. Postoperative forward flexion ranged from 156.8° to 177°. The union rate on postoperative computed tomography scans was 90.3% to 100%, with rates of significant resorption (>50%) ranging from 8.1% to 16%. Biomechanical studies showed that DTA resulted in improved contact pressures, contact areas, and stability when compared with cadaveric models with simulated glenoid bone loss.

Conclusions: The literature on DTA for the management of anterior shoulder instability with glenoid bone loss shows overall excellent results with low rates of recurrent instability and high patient-reported outcome (PRO) scores. Biomechanical studies show that glenoid reconstruction with DTA provides near anatomic reconstruction, leading to increased stability, improved contact area, and decreased loading pressures.

Clinical relevance: The findings of the biomechanical review show that DTA provides highly congruent grafts for glenoid reconstruction. This is important for short-term outcomes including redislocations and PROs, as well as longer-term outcomes including osteoarthritis. Our review of Level III and IV clinical studies shows the clinical implications, with low rates of recurrent instability and high PRO scores.