Total Knee Arthroplasty in the Valgus Knee

Abstract

Purpose: To analyze the clinical and radiographic results after total knee arthroplasty (TKA) in the valgus knee. Materials and Methods: Thirty six knees in 27 patients with a valgus alignment of more than 10 degrees of femorotibial angle underwent TKA. The average follow-up period was 7 years 2 months (1 year to 14 years 5 months). 18 (50%) knees were implanted with a cruciate retaining prosthesis, 17 (47.2%) knees with a posterior stabilized prosthesis, and one (2.8%) knee with a constrained condylar prosthesis. In knees with a preoperative 15 degrees or greater femorotibial angle, the posterior stabilized prostheses were necessary in 85%. Medial parapatellar approach was used in 27 knees with a preoperative valgus 20 degrees or lesser femorotibial angle. With 20 to 29 degrees valgus, medial parapatellar approach was used in 5 knees and lateral parapatellar approach in 2 knees. With 30 degrees or greater valgus, lateral parapatellar approach was used in 2 knees. Results: The mean postoperative Hospital for Special Surgery knee scores were 89.5 points. Postoperative range of motion averaged 114.4 degrees. Postoperative alignment averaged 6.5 degrees valgus. Radiolucent line or loosening was not seen in any knee. There were 2 deep infection in patients whose preoperative femorotibial angle was greater than valgus 20 degrees using lateral parapatellar approach. Conclusion: Clinical and functional results after TKA in valgus knee were similar to those in varus. But, prevention of deep infection in patients with marked valgus angle was important, especially using lateral parapatellar approach. Cruciate retaining, posterior stabilized and constrained condylar prostheses were used in our cases. A more constrained prosthesis was frequently used in more significant valgus deformity. Both medial and lateral parapatellar approaches were used in our cases. But, in severe valgus knee more than 30 degrees, lateral parapatellar approach was necessary.