Ankle prostheses. Mid-term results after Thompson-Richards and STAR prostheses

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Rheumatology

Background:

• Rheumatoid arthritis frequently affects the ankle joint, necessitating surgical intervention.
• Ankle replacement surgery aims to alleviate pain and restore function in patients with severe ankle arthritis.
• Both cemented Thompson-Richards prostheses (TRP) and cementless S. T. A. R. prostheses are utilized for ankle arthroplasty.

Purpose of the Study:

• To compare the clinical and radiological outcomes of cemented Thompson-Richards prostheses and cementless S. T. A. R. prostheses in patients with rheumatoid arthritis.
• To evaluate the long-term survival rates and complication profiles of both prosthesis types.

Main Methods:

• A retrospective study followed 37 patients (37 ankles) with rheumatoid arthritis who underwent ankle arthroplasty.
• Twenty patients received cemented Thompson-Richards prostheses, and 19 received cementless S. T. A. R. prostheses.
• Patient outcomes were assessed using the Kofoed ankle score, radiological examination, and revision rates over a 1-12 year follow-up period.

Main Results:

• The S. T. A. R. group showed a higher mean Kofoed ankle score (86.9 pts) compared to the TRP group (77.7 pts) at follow-up.
• Cemented TRP exhibited a high rate of tibial component radiolucency (53.3%) and three cases of talar subsidence.
• Cementless S. T. A. R. prostheses had minimal radiolucency and no talar subsidence, with a 6-year estimated survival rate of 94.3% versus 87% at 12 years for TRP.

Conclusions:

• Cementless S. T. A. R. prostheses appear to offer better clinical and radiological results than cemented Thompson-Richards prostheses in rheumatoid arthritis patients.
• The S. T. A. R. prosthesis demonstrated a lower incidence of radiolucency and subsidence, contributing to a higher survival rate.
• Further long-term studies are warranted to confirm these findings and optimize ankle arthroplasty techniques.