Use of a semi-constrained implant in revision knee arthroplasty produced acceptable implant survival and functional outcomes during the long-term follow-up period, according to study results.
Researchers performed 234 semi-constrained revision total knee arthroplasties (TKAs) in 209 patients between January 1995 and December 2000 with a semi-constrained modular fixed-bearing implant system. Primary outcomes included implant survival as determined by repeat revision surgery, including removal of any component, and secondary outcomes included range of motion, pain, Knee Society Clinical and Functional Scores and patient satisfaction. Mean follow-up was 9 years.
Seventeen percent of knees required repeat revision surgery, with aseptic loosening, osteolysis or pain as the most common reasons cited. Infection resulted in revision surgery in 45% of knees. Risk for revision was significantly increased by male gender.
Patients’ 5-year survival rate was 91%, and 10-year survival rate was 81%, according to the researchers. Those who had survived with 10 years of follow-up experienced a significant improvement in range of motion, as well as improvement in pain levels. Although the average Clinical Knee Society Score improved from 53.7 preoperatively to 83.7 at last follow-up, the researchers found no significant change in functional score, which increased from 47 preoperatively to 49 at last follow-up.
At 10-year follow-up, 90% of patients reported overall improvement in their knee compared with their preoperative condition, according to study results.
Disclosure: Trousdale received royalties from DePuy, Mako and Wright Medical, and is a board member for the Journal of Arthroplasty, the Knee Society and the American Association of Hip and Knee Surgeons.