One hundred and thirty-six patients who underwent total knee replacement arthroplasty (TKRA) with NexGen®-LPS were analyzed for the clinical and radiologic results after a minimum follow-up of 5-years.

This study included 136 patients (209 knees) who underwent TKRA with NexGen®-LPS between August 1998 and February 2005 and had a minimum follow-up of 5 years. We evaluated the range of motion (ROM), American Knee Society knee functional scores, radiographic results and complication rates in the study subjects with an average 8.3 years of follow-up (range: 5-11.5 years). We also compared the results of the degenerative arthritis group (195 knees in 129 patients) with those of the rheumatoid arthritis group (14 knees in 7 patients).

The mean ROM increased from 107.3° to 122° at the final follow-up. The flexion contracture also improved from 8.3° to 1.2° at final follow-up. The knee score improved from 51 to 94.7 at the final follow-up. The functional score improved from 38 to 84.2 (p<0.05) at final follow-up. There was no statistical significant difference in the results between the degenerative arthritis and rheumatoid arthritis groups (p>0.05). Valgus (α), varus (β), flexion (γ) and the posterior slope angle (δ) of the tibial components were well maintained both during the immediate postoperative period and at the final follow-up. There was no significant difference in the tibiofemoral angle and α, β, γ and δ angle (p>0.05) between the degenerative arthritis and rheumatoid arthritis groups. The alignment of the alternative substance was also relatively well maintained. Radiolucent lines were observed in 39 knees (18.7%), and in 42 zones out of 209 knees. The most common site of radiolucent lines was the medial side of the tibia in 21 knees. The overall incidence of radiolucent lines was 15% for the femur, 61% for the tibia and 24% for the patella. There was no statistically significant difference between the presence of radiolucent lines and the clinical results (p>0.05). There was 1 case of revision surgery due to loosening of implants at 8 years after surgery, but no early loosening was observed in the study subjects. Complications were found in 6 patients. Two patients with early postoperative infection were treated with revision surgery. Two patients with acute hematogenous infection 4 years after the initial operation were treated with revision surgery. Two patients with superficial infection were treated with antibiotics and regular dressing.

The patients treated with the NexGen®-LPS TKRA had a decreased level of postoperative pain and an improved knee joint ROM. A lower rate of complications was also found with this type of implant.