Results of High-Flex Total Knee Arthroplasty: Minimum 3-Year Follow-Up Result / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to evaluate the results of high-flexion total knee arthroplasty. MATERIALS AND METHODS: We evaluated 355 patients (372 cases) who underwent total knee arthroplasty using high-flexion implants from January 2005 to December 2011. The patients included 36 men and 336 women with a mean age of 70.6 (52-88 years) years. Average follow-up duration was 59 months (36-77 months) months. Three types of high flexion implants were used in this study. We performed preoperative assessment and last follow-up clinical evaluation was performed using range of motion (ROM), knee score and function score according to the knee society clinical rating system and complications. Radiologic evaluation was performed using plain radiographs to evaluate loosening or osteolysis. RESULTS: The mean ROM increased from 114.9° preoperatively to 127.0° at the final follow-up. The average knee score improved from 60.5 points preoperatively to 90.9 points at final follow-up and knee function score improved from 49.0 to 84.4 points. The clinical results were improved in each type of implants. A radiolucent line was detected in 2 cases in the Sigma rotating platform flexion group and patellar tendon rupture occurred in 1 case in the NexGex legacy posterior-stabilized-flex group. Infection occurred in 2 cases after 2 and 5 years postoperatively in the Scorpio non-restrictive geometry group and were treated with revision arthroplasty. No significant loosening was observed. CONCLUSION: This study obtained good results after total knee arthroplasty using high-flexion implants, and no loosening was observed. There were no differences in the type of implants in regard to the ROM and clinical variables.

The Mid-Term Results of High-Flex Total Knee Arthroplasty: Minimum 5-Year Follow-Up Results / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to evaluate the mid-term results of high-flexion total knee arthroplasty. MATERIALS AND METHODS: We retrospectively reviewed 77 patients who underwent 119 total knee arthroplastys using high-flexion implants (LPS-flex(R) , Zimmer, Warsaw, IN, USA) from November 2004 to June 2006. The mean age was 67.3 years (range, 54-83 years), and the average follow-up duration was 71.1 months. We assessed preoperative and last follow-up functional outcomes with ranges of motion (ROM) and the Hospital for Special Surgery (HSS) score and investigated their ability to squat, sit cross-legged knee, kneel, or stand up from the floor or a chair at the final follow-up. The Knee Society Radiographic evaluation and scoring system was used for radiologic evaluation. RESULTS: The mean ROM increased from 104.7degrees preoperatively to 129.8degrees postoperatively at the final follow-up. The average HSS score improved from 42.7 points preoperatively to 93.5 points postoperatively. At the final follow-up, 33 patients (42.8%) were able to squat; 75 patients (97.4%) were able to sit cross-legged; 27 patients (35.0%) were able to kneel; 45 patients (58.4%) were able to stand up from the floor and 73 patients (94.8%) were able to stand up from a chair. Six cases encountered stiff knees as a complications, and were treated with manipulation procedures. 1 mm radiolucent lines were detected in 5 cases, but none of them were progressive. CONCLUSION: We believe that the hyperflexion implant itself is not a cause of early loosening. Research on reasons regarding early loosening and long-term follow-ups will be needed.