High-flexion Prosthesis Improves Function of TKA in Asian Patients Without Decreasing Early Survivorship

Abstract

Background Two previous studies recently raised the possibility of a high risk of early femoral components loosening with high-flexion (HF) prostheses in Asian populations and suggested that the high failure rate of HF TKAs was associated with HF ability. However, these findings are controversial given other studies reporting a low incidence of aseptic failures in HF prostheses.Questions/purposes We therefore determined (1) the rate of achieving postoperative HF after HF TKA; (2) whether the aseptic loosening rate of HF prostheses is high; and (3) whether the survivorship was worsened in patients who achieved postoperative deep knee flexion in our cohort of Korean patients. Methods We retrospectively reviewed 488 patients who had 698 primary TKAs using the NexGen 1 Legacy Posterior-Stabilized Flex system implanted from 2003 to 2010. There were 40 men and 448 women with a mean age of 68 years. We obtained Hospital for Special Surgery scores, maximal flexion, and radiographs. The minimum followup for functional and radiographic evaluations was 2 years (median, 4.8 years; range, 2-8.7 years). We performed a survival analysis on all patients for aseptic loosening. Results Three hundred sixty knees (52%) could achieve C 135°maximum flexion. Six of the 698 knees (0.9%) developed aseptic loosening (three femoral and three tibial). The survival at 5 years for aseptic loosening was 99.1%. The overall survival for aseptic failure did not differ between knees that achieved HF and those that did not.

No Clinical Benefit of High-Flex Total Knee Arthroplasty. A Meta-Analysis of Randomized Controlled Trials

“…Nevertheless, we did not observe any obviously increased rate of early loosening, anterior knee pain or patellar crepitus in patients using high-flex implants. Many current literatures [21,41,42,[47][48][49][50] supported our findings.…”

Necessary Factors to Achieve Deep Flexion for Asian Populations after Oxford Unicompartmental Knee Arthroplasty

“…140 degrees. [12][13][14] In our clinical experience, some patients with ideally implanted components and postoperative maximum flexion angle ! 130 degrees are not satisfied with the outcomes, partly because of the poor flexion angle.…”

Early Clinical and Radiological outcomes of the New Anatomic Knee System : Minimum 3-year Follow-up.

“…The position of the zones was used to describe the location of the radiolucencies followed by the Knee Society total knee replacement radiological assessment of the radiolucent lines [31,32]. It was related to aseptic implant loosening [30,34].…”