Early Results of Total Knee Arthroplasty Using a Built-in 3-Degree External Rotation Prosthesis

PURPOSE: We compared the outcomes of total knee arthroplasty (TKA) using the Genesis II prosthesis in which 3degrees of external rotation was incorporated into the femoral component and Nexgen LPS prosthesis in which the degree of external rotation was determined by the extent of intraoperative bone cutting. MATERIALS AND METHODS: Of the patients who underwent TKA for osteoarthritis between November 2006 and December 2009, 326 patients (572 knees) were included in this study. The prosthesis of choice was Genesis II in 199 knees and Nexgen LPS in 373 knees. The mean follow-up was 27 months (range, 24 to 51 months). The American Knee Society score (KSS) and function score (FS) were used for clinical assessments. The maximum flexion angle and patellar tilt were compared between the groups. RESULTS: At the final follow-up, no significant intergroup difference was observed regarding the KSS (p=0.217), FS (p=0.238), maximum flexion angle (p=0.124), and patellar tilt (p=0.156). CONCLUSIONS: There was no significant difference in the clinical outcomes and patellar tilt between the prosthesis in which 3degrees of external rotation was incorporated into the femoral component and the prosthesis in which external rotation was determined based on bone cutting.

Comparative Study between the Group with Lateral Retinacular Release and the Group without Lateral Retinacular Release Following Total Knee Arthroplasty

PURPOSE: We compared the results of total knee arthroplasties combined with lateral retinacular release with those without lateral retinacular release. MATERIALS AND METHODS: Results of 277 total knee arthroplasties from 1996 to 2002, follow up for at least one year ( average follow-up periods : 32 months). Lateral retinacular release was performed in 190 knees (70.1%) and not performed in 87 knees (29.9%). The clinical results of total knee arthroplasties were evaluated by the Knee Scoring System of hospital for Special Surgery (HSS) and range of motion. The patello-femoral complications were evaluated by tilt and displacement of patella at the last follow-up Hughston 's view. Osteonecrosis and fracture of patella were evaluated by simple x-ray. RESULTS: HSS score and range of motion improved postoperatively in both groups, but there was no sig-nificant difference between the two groups. There were 3 cases (3.4%) with patellar subluxations and 1 case (1.1%) with patellar dislocation in the group without lateral retinacular release. There was no avascu-lar necrosis or fracture of patella in either group. CONCLUSION: We suggest that lateral retinacular release can be performed without great risk of potential patellar complications in total knee arthroplasties requiring lateral retinacular release for proper patellar tracking.