Primary Total Knee Arthroplasty in Patients With Fixed Valgus Deformity

Ninety-nine knees in 81 patients evaluated from two to ten years and having enough valgus deformity to require specific soft-tissue release were studied. They were also compared to a control group of 40 knees in 31 patients with no angular deformity greater than 5°, who were matched for age and diagnosis. All procedures were performed using a minimally constrained, posterior-cruciateligament-sparing prosthesis. Pre- and postoperative axial alignment was measured on weight-bearing long-standing roentgenographs. Analysis included examination for lucent lines in postoperative fluoroscopically positioned roentgenographs and clinical data summarized using the 100-point scoring systems developed by The Knee Society. Knees were classified as having Type I, II, or III valgus deformities: Type I was defined as valgus deformity secondary to bone loss in the lateral compartment and soft-tissue contracture with medial soft tissues intact; Type II was defined as obvious attenuation of the medial capsular ligament complex; and Type III was defined as severe valgus deformity with valgus malpositioning of the proximal tibial joint line after overcorrected proximal tibial osteotomy. Only cases of Type I and Type II were represented in the 99 knees reported. Type I patients were treated with lateral soft-tissue release, and Type II patients were treated with medial capsular ligament tightening (i.e., ligament reconstruction procedures on the medial side). The Knee Society postoperative knee score was 87.6 (10.6) and mean postoperative functional score was 52.3. Alignment was well corrected and knee scores for the Type I and II groups were almost identical as were the functional scores. The results were grouped as 72% excellent, 18% good, 7% fair, and 2% poor. Notably, the control group was 39 of 40 patients excellent, and only one poor. Ligament stability was satisfactorily established by lateral release in Type I and with the combined medial plication in the Type II patients. The ligament-tightening procedures were on the average 40 minutes longer than those for the Type I or the control groups. The controversial nature of the simultaneous ligament reconstruction method is recognized, but good experience is reported.