A1149. A NEW TECHNIQUE FOR CORRECTING VARUS DEFORMITY AND FLEXION CONTRACTURE DURING TOTAL KNEE ARTHROPLASTY: THE “INSIDE-OUT” TECHNIQUE

Abstract

Introduction: In 1979, our senior author described his technique for correcting a flexion contracture during total knee arthroplasty (TKA) by additional resection of the distal femur and posterior capsular release; he also described his method of correction of a varus deformity by raising a subperiosteal sleeve from the proximal tibia. Due to concerns related to elevation of the joint line as well as flexion/extension gap asymmetry and instability, our technique has evolved into a methodical soft tissue release at the level of the joint line. Our hypothesis is that this technique effectively corrects both deformities, while reducing the complications related to the more traditional techniques.

The purpose of this study is to describe this technique and assess its effectiveness in a series of 31 consecutive patients.

Technique: Highlights of this technique are as follows:

1. This method involves osseous resections of 10mm from the level of the uninvolved surfaces of the femur and tibia in order to restore the mechanical axis.

2. A transverse release of the contracted posterior capsule is performed with electrocautery at the level of the tibial resection from the posterior margin of the superficial medial collateral ligament (MCL) to the posterolateral corner of the tibia.

3. A controlled lengthening of the superficial MCL is achieved by pie-crusting.

Results: Over a 12 month span, we have corrected these biplanar deformities in 31 knees without residual instability. There were no residual flexion contractures greater than 5 degrees. The maximum varus corrected was 30 degrees, and the maximum flexion contracture corrected was 20 degrees. The mean coronal plane correction was to 5.5 degrees of valgus (range: 1 to 9 degrees).

Discussion: In a series of 31 consecutive patients, this technique was effective in correcting both deformities. We achieved a mean range of motion of 115 degrees, while avoiding elevation of the joint line or instability. Theoretically, this method should result in more optimal knee mechanics than traditional methods. While we are reporting good early results, a prospective, randomized controlled study is needed to better evaluate this technique.