Clinical outcome, functional outcome and patient satisfaction after cruciate retaining total knee arthroplasty for stiff arthritic knee - A short term outcome study

Background: Various authors have shown that Cruciate Retaining (CR) Total Knee Arthroplasty (TKA) has better long-term survivorship compared to Posterior Stabilized (PS), however most arthroplasty surgeons tend to use PS knees in patients with severe deformity and stiffness. There is limited data correlating stiffness and CR versus PS design. The aim of our study was to assess the outcome of CR TKA for patients with stiff arthritic knee. Materials & methods: We evaluated the results of 30 knees with osteoarthritis and inflammatory arthritis and preoperative stiffness (ROM 15-90 degrees), who had been treated with CR TKA with a mean follow up of 2 years. The primary outcome variable measures were improvement in the flexion, flexion deformity (FFD) and overall im- provement in the arc of motion. Patients were also evaluated by Knee Society Score (KSS), WOMAC score and 5-point Likert scale for patient satisfaction. Result: At the time of final follow-up, the mean arc of motion improved from 75 degrees preoperatively to 108 degrees post-operatively and it was statistically significant (p < 0.001). Similar improvement was noted for FFD (15.43 degrees to 0.83 degrees (p < 0.001)), maximum flexion from 90.9 degrees to 109.1 degrees (p < 0.001), KSS clinical from 37.67 to 87.47 (p < 0.001), KSS functional from 58.5 to 93.83 (p < 0.001), WOMAC from 76.73 to 7.63 (p < 0.001). Further, the Likert Scale for patient satisfaction was excellent for 90% of the patients. Conclusion: This study clearly shows that the routine use of PS design for complex stiff knees has questionable scientific intent and standard CR TKA design in stiff knees can produce excellent outcome. Since there is slight preponderance of data pointing towards improved longevity with CR design, it would be a better option for the patients with longer life expectancy.