Mid-Term outcomes following fresh-frozen humeral head osteochondral allograft reconstruction for reverse Hill Sachs lesion: a case series

Background: Locked posterior glenohumeral dislocations with a reverse Hill-Sachs impaction fracture involving less than 30% of the humeral head are most frequently treated with lesser tuberosity transfer into the defect, whereas those involving more than 50% undergo humeral head arthroplasty. Reconstruction of the defect with segmental femoral osteochondral allografts has been proposed to treat patients between these two ranges, but the medium-/long-term outcomes of this joint-preserving procedure are controversial. Methods: Between 2001 and 2018, 12 consecutive patients with a unilateral locked posterior shoulder dislocation and an impaction fracture from 30 to 50% (mean 31% +/- 1.32) of the humeral head were treated with segmental reconstruction of the defect with fresh-frozen humeral head osteochondral allografts. Patients were assessed clinically, radiographically and with computed tomography (CT) at a medium follow-up of 66 +/- 50.25 months (range, 24-225). Results: All twelve shoulders presented a slight limitation in anterior elevation (average, 166.6 degrees +/- 22.76). The mean active external rotation with the shoulder at 90 degrees of abduction was 82.5 degrees +/- 6.61, and that with the arm held in stable adduction was 79.16 +/- 18.80. The mean abduction was 156.25 degrees +/- 25.09. The mean Constant-Murley score (CS) was 82 +/- 15.09 points (range, 40-97 points), and the mean ASES was 94 +/- 8.49 points. The mean pre- and postoperatively Western Ontario Shoulder Instability index (WOSI) was 236.5 +/- 227.9 and 11.20 +/- 10.85, respectively. Development of osteoarthrosis (OA) was minimal. The average allograft resorption rate was 4% +/- 2.4. There were no cases of failure (reoperation for any reason) in this series. Conclusion: Segmental humeral head reconstruction with humeral head fresh-frozen osteochondral allografts provides good to excellent clinical results with low-grade OA and low allograft resorption in patients with locked posterior shoulder dislocation. Level of evidence Level IV, Case Series, Treatment Study.