Design modifications of high-flexion TKA do not improve short term clinical and radiographic outcomes

Two- to Four-Year Follow-up Results of Total Knee Arthroplasty Using a New High-Flexion Prosthesis

Purpose

The purpose of this study was to evaluate minimum 2-year follow-up results of total knee arthroplasty (TKA) performed using a new high-flexion prosthesis design (LOSPA).

Materials and Methods

The 2- to 4-year results of 191 consecutive TKAs (177 patients) with the LOSPA posterior-stabilized prosthesis were evaluated. The patients were assessed clinically and radiographically using the Knee Society scoring system (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

Results

The mean range of motion (ROM) increased significantly from 117.4° (range, 75° to 140°) preoperatively to 126.7° (range, 80° to 144°) postoperatively (p<0.001). The mean KSS and WOMAC scores improved significantly from 121.4 (range, 42 to 185) and 56.1 (range, 23 to 88) preoperatively to 174.0 (range, 130 to 200) and 16.4 (range, 0 to 85) postoperatively, respectively (both, p<0.001). One knee required revision for deep infection. No knee had aseptic loosening or osteolysis. Radiolucent lines were noted in 15 knees (7.9%).

Conclusions

The new high-flexion total knee prosthesis resulted in no early aseptic loosening of the component and improved postoperative ROM comparable to other high-flexion TKA prostheses at 2- to 4-year follow-ups.