Distal Tibial Allograft Glenoid Reconstruction for Recurrent Shoulder Instability: Clinical Outcomes and Complications

OBJECTIVES: Treatment options for recurrent shoulder instability, in the setting of significant glenoid bone loss, consists of several iterations of bone stabilization procedures. However, advanced arthritic changes with the Laterjet procedure and rapid resorption changes with the iliac crest bone graft reconstruction has led into the search for more optimal surgical reconstruction options. The purpose of this study is to evaluate the clinical and functional outcomes of patients with recurrent shoulder instability, with significant glenoid bone loss, treated with fresh distal tibial allograft reconstruction with regards to recurrence, revision surgery, and complications. METHODS: At a single institution, all consecutive patients with recurrent shoulder instability and at least 15% anterior glenoid bone loss, undergoing distal tibial allograft reconstruction, between 2011 to 2016, were identified by diagnostic and procedural codes. All clinical notes, diagnostic imaging, and operative reports were reviewed in detail. From these sources, demographics, operative techniques, and radiographic parameters were collected and measured. Functional outcome scores were prospectively collected from patients. The primary outcome of the study was the Disability of Arm, Shoulder, Hand (DASH) score. The secondary outcomes of the study were the Visual Analog Scale (VAS) pain score, Single Assessment Numeric Evaluation (SANE) score, recurrent instability, revision surgery, and complications. RESULTS: At 6 years, there were a total of 36 distal tibial allograft reconstructions performed in patients with recurrent shoulder instability in the setting of significant glenoid bone loss. Amongst this cohort, average age was 35 years old with 72% of patients being male. The dominant extremity was involved in 20 (56%) of patients and 24 (67%) of patients had previous surgery to address episodes of shoulder instability. Follow-up, for the entire cohort was on average 15.5 months. In comparison to preoperative range of motion, after surgery there was significantly less abduction (P=0.01). At final follow-up, patients undergoing distial tibial allograft reconstruction showed trend towards significant improvement in the DASH score (preoperative DASH=50.7, postoperative DASH=37.1, P=0.09). In like manner, there was significant improvement in both the VAS score (P=0.001) and the SANE score (P=0.002). There was no significant difference in functional outcome scores between those patients who had failed a previous surgery for instability. Recurrent instability, after distal tibial allograft reconstruction, occurred in 4 (11%) of patients and 8 (22%) of patients underwent an additional surgical procedure. Complications occurred in 31% of patients, with the most common complication being rupture of the subscapularis. CONCLUSION: This study provides functional outcomes in one of the largest consecutive cohort of patients undergoing distal tibial allograft reconstruction for recurrent shoulder instability due to significant glenoid bone loss. The study suggests that distal tibial allograft reconstruction may provide improved functional outcomes in patients with recurrent shoulder instability. After this procedure, 89% of patients did not experience any additional episodes of shoulder instability. Despite these encouraging results, complications are common after this procedure, with 31% of patients experiencing a complication.