Clinical outcomes of modular segmental megaprosthesis for revision shoulder arthroplasty with severe proximal humerus bone loss at a minimum two year follow-up

Significant proximal humerus bone loss poses a challenge on the outcomes of traditional reverse shoulder arthroplasty implants. Modular Segmental Megaprosthesis (MSM) offers a potential solution to shoulder reconstruction without the need for allograft. However, clinical outcomes of MSM are restricted to case reports and small case series with limited follow-up.

An Institutional Joint Registry Database was used to identify revision shoulder arthroplasty patients using MSM. A retrospective review evaluated implant survivorship, pain relief and functional outcomes at a minimum of 2-year follow-up.

Between 2014 and 2022, a total of 28 patients with significant proximal humerus bone loss who underwent revision shoulder arthroplasty reconstruction using MSM were included in this study. At a minimum of 2-year follow-up, the MSM implant survivorship was 85.7% (24 out of 28). Pain level decreased from 7 out of 10 preoperatively to 2 at the 2-year follow-up mark (P = .001). Range of motion also improved: elevation increased from 46° preoperatively to 102° postoperatively (P = .004); abduction improved from 33° to 92° (P = 0.002); and external rotation increased from 13° to 31°(P = .036), respectively. Constant Score increased from 12.9 preoperatively to 69.6 at 2-years after surgery (P = .008). The American Shoulder and Elbow Surgeons score increased from 7.4 to 77.2 (P = .008), and Simple Shoulder Test (SST) increased from 11.1 to 68.1%, respectively (P = .008).

The MSM presented a good 2-year survivorship. It demonstrated significant improvement in pain and function in patients with proximal humerus bone loss that underwent arthroplasty revision. These findings support the use of MSM as a salvage procedure in complex shoulder reconstructions.