Effect of Posterior Femoral Condylar Offset (Pco) on Clinical Results of Single-Radius (Sr) Femoral Design Implants/Components in Posterior Stabilized Total Knee Arthroplasty (Ps Tka)

Background:Total knee arthroplasty (TKA) is gold standard treatment of choice for Osteoarthritis (OA) knee. When a sufcient posterior femoral condylar offset (PCO) is reconstructed, a larger posterior clearance may be obtained that helps delay impingement on the posterior aspect and maximizes range of exion (ROF). However, the potential correlation between PCO and ROF, especially after posteriorly stabilized (PS) TKA, remains controversial. This study was carried out with the objective to study the effect of PCO on clinical results on single-radius (SR) femoral design components in PS TKA. Material and methods: This hospital based prospective observational study was conducted at Department of Orthopedic, Santokba Durlabhji Memorial Hospital, Jaipur, Rajasthan. Between the duration of 1 January 2018 to 31 December 2018 with 6 months follow up. 50 consecutive patients were operated the with Single radius femoral design implant (SR) - Stryker Scorpio NRG PS design by a single surgeon. Measurement of posterior condylar offset, exion (weight bearing and non-weight bearing) and knee society scoring (KSS) system were taken preoperative and post operatively 6 months. Appropriate statistical tests were used and results were interpreted. Result: The mean age was found 64.36 ± 7.63 years. Mostly cases (44%) were in the age group 50-60 years. Female predominance (70%) was observed. The preoperative PCO was 27.66 ± 3.20 mm and the Post-operative PCO was 29.42 ± 2.52 mm. The pre-operative exion was 112.70±8.09degrees. The post-operative exion was121.60±3.97degrees. The mean pre-operative weight bearing exion was102.70± 7.37degrees. The mean postoperative weight bearing exion was 124.50 ± 3.81degrees. Mean pre-op knee score was 55.88 ± 3.00 while mean pre-op function score was 28.40 ± 10.42. Mean post-op knee score was 84.86 ± 2.07 while mean post-op function score was 82.60 ± 4.43. Mean pre-operative and post-operative paired differences for PCO, exion non-weight wearing, exion weight bearing, KSS knee score, KSS function score were found highly statistically signicant for all variables. Insignicant, negative and poor correlation was observed between change in PCO and other variables like non-weight bearing exion, KSS knee score, KSS function score, and weight bearing exion (Pearson correlation values were -0.004, P value = 0.976; -0.224, P value = 0.118; -0.036, P value = 0.805 and -0.057, P value = 0.694 respectively. Conclusion: There was signicant increase in PCO, exion (both weight bearing and non-weight bearing), KSS knee score and function scores.