Proximal humeral replacement using a fixed-fulcrum endoprosthesis

Area of Science:

• Orthopedic Surgery
• Oncology
• Biomedical Engineering

Background:

• Tumors of the proximal humerus require surgical intervention, often necessitating complex reconstructive procedures.
• Massive endoprosthetic replacement is a common surgical option for proximal humerus tumor resection.
• Previous endoprosthetic designs faced challenges with instability and dislocation.

Purpose of the Study:

• To evaluate the long-term outcomes of proximal humerus tumor replacement using a fixed-fulcrum massive endoprosthesis.
• To assess the efficacy of a novel constrained humeral liner in reducing dislocation rates.
• To compare functional outcomes between the original prosthesis and the modified prosthesis with the constrained liner.

Main Methods:

• A retrospective review of 68 consecutive patients who underwent proximal humerus tumor replacement between 1997 and 2007.
• Assessment of functional outcomes using the Musculoskeletal Tumor Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS).
• Analysis of complication rates, specifically focusing on prosthetic dislocation, and comparison between the original and constrained liner designs.

Main Results:

• The study included 42 surviving patients with a mean follow-up of 5 years and 11 months.
• The mean MSTS score was 72.3% and the mean TESS score was 77.2% for the overall cohort.
• The original prosthesis had a dislocation rate of 25.9%; however, no dislocations occurred in the four patients who received the new constrained humeral liner.

Conclusions:

• Endoprosthetic replacement for proximal humerus tumors using the fixed-fulcrum prosthesis is a reliable procedure with good functional outcomes.
• The introduction of a constrained humeral liner significantly mitigates the risk of dislocation, enhancing prosthesis performance.
• This improved prosthesis design offers a reliable solution for proximal humerus tumor reconstruction, minimizing major complications.