Quality of life and clinical outcome in salvage revision total knee replacement: hinged vs. total condylar design

This study compared the overall outcome after salvage revision total knee arthroplasty using hinged and nonhinged designs. We followed 26 total knee arthroplasties for an average of 20.4 months. The average age was 68.5 years. All patients had a salvage situation secondary to excessive bone loss, enlarged flexion gap, collateral ligament insufficiency, or extensor mechanism insufficiency. Ten patients received a hinged implant after an average of 2.8 prior total knee replacements. Sixteen patients received nonhinged constrained implants after an average of 3.4 prior total knee replacements. The outcome was evaluated using the Hospital for Special Surgery Score (HSS), the Knee Society Score (KSS), the Visual Analogue Scale for pain (VAS), the Tegner Activity Score, the Patella Score, and the Short Form-36 Health Survey (SF-36). There was a statistically significant difference in flexion range of motion between hinged and nonhinged designs (96.5degrees vs. 107.5degrees) but not in HSS, KSS, VAS, Tegner Activity Score, or Patella Score. Patients with hinged and nonhinged prostheses had significantly lower scores than an age-matched normal population in physical functioning, role limitations, and bodily pain on the SF-36 survey. However, patients with a hinged implant had no statistically significant difference compared to controls in the mental component summary. In salvage total knee arthroplasty the implant design does not significantly affect the overall functional outcome. However, patients with a hinged implant had significant better scores in the mental components of the SF36 quality-of-life assessment.