Range of motion, knee scores comparable in high flexion and standard TKA designs

OSLO — Despite some touted advantages to obtaining high flexion in total knee arthroplasty, a Korean prospective randomized study found no differences at 2 years follow-up in results with a high flexion and a standard design implant.

Myung Chul Lee, MD, and colleagues in the Department of Orthopaedic Surgery at Seoul National University College of Medicine, Korea, randomized 170 patients to be implanted with the posterior stabilized PFC Sigma Rotating Platform (PS RP-MB) total knee arthroplasty (TKA) implant or the High Flexion PS RP-MB TKA implant (both from DePuy, a Johnson & Johnson company) for the indication of osteoarthritis. In all, 85 patients received the standard mobile bearing prosthesis and 85 patients received the high flexion version of the implant.

At the 2010 ESSKA Congress, here, Lee said that in following these patients for a minimum of 2 years for range of motion, American Knee Society score, Hospital for Special Surgery knee score and WOMAC score, “We were not able to find any advantages of the high flexion RP over the standard RP at this point.”

No radiographic differences

In some cases follow-up exceeded 3 years, according to Lee.

He and his colleagues also found no significant differences or changes between the groups in such critical aspects of the postoperative radiographs as femorotibial angle, tibial slope and posterior condylar offset.

The groups were the same preoperatively, Lee said. Neither group experienced aseptic loosening or osteolysis, according to the abstract.

“The number of patients who were satisfied or very satisfied was 91% in both [groups],” he said.

Reference:
Lee M, Choi W, Lee S, et al. Comparison of outcomes after standard and high-flexion posterior stabilized rotating-platform mobile-bearing TKA Paper #FP12-1212. Presented at the 2010 ESSKA Congress. June 9-12, 2010. Oslo.