The "Inside-Out" Technique for Correcting a Fixed Varus Deformity with Flexion Contracture in Total Knee Arthroplasty.

INTRODUCTION

The inside-out technique is a safe and reproducible method to effectively correct a fixed varus-flexion deformity during total knee arthroplasty by performing a posteromedial capsular release and so-called pie-crust lengthening of the superficial medial collateral ligament (sMCL).

STEP 1 PREOPERATIVE PLANNING: Analyze preoperative radiographs as a key step in planning the surgery for the required amount of osseous cuts and soft-tissue release.

STEP 2 EXPOSURE: Obtain adequate exposure for proper visualization and assessment.

STEP 3 TIBIAL AND FEMORAL CUTS: Adequate bone cuts with proper alignment are an essential step of this technique.

STEP 4 POSTEROMEDIAL CAPSULOTOMY: This is the most important step for extension balancing in knees with flexion contracture; the posteromedial aspect of the capsule in varus deformity should be safely incised at the level of the tibial cut.

STEP 5 PIE-CRUSTING OF THE SMCL: Perform pie-crusting followed by serial manipulations in a controlled manner to avoid overrelease of the sMCL.

STEP 6 FLEXION GAP BALANCING: This is a key step for proper balancing, femoral sizing, rotation, lateralization, and patellofemoral tracking.

RESULTS

From October 2006 to December 2009, thirty-one consecutive patients (thirty-four knees) with a severe fixed varus-flexion deformity (varus alignment of ≥15° and flexion contracture of ≥5°) underwent total knee arthroplasty with the inside-out technique.

WHAT TO WATCH FOR: IndicationsContraindicationsPitfalls & Challenges.