Allograft-Prosthetic Composite Reconstruction for Massive Proximal Humeral Bone Loss in Reverse Shoulder Arthroplasty

Background: Reverse total shoulder arthroplasty (RTSA) performed in the setting of massive proximal humeral bone loss often requires special reconstructive techniques. Restoration of the proximal part of the humerus with an allograft provides a number of theoretical benefits, including implant support, restoration of humeral length, deltoid tensioning, and an opportunity to repair the posterior aspect of the cuff to improve strength in external rotation and repair of the subscapularis to improve stability. However, reverse allograft-prosthesis composites (APCs) are costly, are technically demanding to use, and can be compromised by progressive allograft resorption.

Methods: Between 2005 and 2012, the lead author used an APC reconstruction in 8 primary and 18 revision RTSAs (26 patients; mean age, 62 years; mean body mass index, 27.9 kg/m2). The indications for the primary RTSAs included severe proximal humeral bone loss after trauma (n = 5) and tumor resection (n = 3). The indications in the revision setting were failed hemiarthroplasty (n = 11), anatomic total shoulder arthroplasty (n = 4), and reverse arthroplasty (n = 3). The most common reason for revision was instability (n = 10). A compression plate was used for graft-to-host fixation in all shoulders. Shoulders were assessed for pain, motion, American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, Neer score, revision or reoperation, radiographic evidence of graft union or resorption, and implant fixation. The mean duration of follow-up was 4 years (range, 2 to 10 years).

Results: RTSA using an APC construct resulted in substantial improvements in pain scores (p < 0.0001), elevation (p < 0.0001), and external rotation (p = 0.004). With the numbers available, there were no significant differences in clinical outcomes between primary and revision cases. No patients required revision surgery for nonunion at the host-allograft junction. The mean time to union was 7 months, with 1 patient requiring bone-grafting for delayed union. Other complications included dislocation, deep infection, graft fracture, and periprosthetic fracture distal to the previous APC construct in 1 patient each. The 2 and 5-year revision-free survival rate was 96%.

Conclusions: Reconstruction of proximal humeral bone loss with an APC at the time of primary or revision RTSA is safe and effective, with acceptable functional outcomes and complication rates.

Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.