Humeral shaft periprosthetic fractures: Fracture patterns differ between short and standard-length arthroplasty stems

There have been no published studies evaluating the impact of humeral stem length on humeral shaft periprosthetic fractures. We sought evaluate the differences in fracture patterns between periprosthetic fractures around a short stem and standard stem humeral implants.

This is a retrospective cohort study. Patients sustaining a humeral shaft periprosthetic fracture around shoulder arthroplasty implants from December 2011 to January 2021 were identified using ICD-9/10 codes. Three upper extremity trained surgeons evaluated all radiographs assessing fracture location and configuration, as well as signs of stem stability before and after the fracture. They classified the fractures based on two classification schemes: Wright & Cofield, and the Unified Classification System (UCS), and they recorded their recommended treatment for each case based on fracture pattens and implant stability.

76 patients with periprosthetic humeral shaft fractures were identified and divided into two groups: short stem (n=18) and standard stem (n=58). Patients with a short stem were more likely to be classified as having an unstable prosthesis after fracture (67% versus 33%, p=0.01). Additionally, the proposed plan for treatment was different between the two groups (p=0.004): more patients in the standard stem group were recommended open reduction internal fixation (50% vs. 33%) or non-operative treatment (17% vs. 0%), and more patients in the short stem group were recommended revision arthroplasty (50% vs. 29%).

Patients sustaining a periprosthetic fracture around a short implant may be more likely to have an unstable prosthesis compared to a standard stem, which may have an impact on treatment options.

Prognosis Study, Level III.