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

[Introduction][1] 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][2] Analyze preoperative radiographs as a key step in planning the surgery for the required amount of osseous cuts and soft-tissue release. ![Figure][3] [Step 2: Exposure][4] Obtain adequate exposure for proper visualization and assessment. ![Figure][3] [Step 3: Tibial and Femoral Cuts][5] Adequate bone cuts with proper alignment are an essential step of this technique. ![Figure][3] [Step 4: Posteromedial Capsulotomy][6] 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. ![Figure][3] ![Figure][3] ![Figure][3] [Step 5: Pie-Crusting of the sMCL][7] Perform pie-crusting followed by serial manipulations in a controlled manner to avoid overrelease of the sMCL. ![Figure][3] ![Figure][3] [Step 6: Flexion Gap Balancing][8] This is a key step for proper balancing, femoral sizing, rotation, lateralization, and patellofemoral tracking. ![Figure][3] ![Figure][3] [Results][9] 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. ![Figure][3] [What to Watch For][10] [Indications][11] [Contraindications][12] [Pitfalls & Challenges][13] [Introduction][1] 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][2] Analyze preoperative radiographs as a key step in planning the surgery for the required amount of osseous cuts and soft-tissue release. ![Figure][3] [Step 2: Exposure][4] Obtain adequate exposure for proper visualization and assessment. ![Figure][3] [Step 3: Tibial and Femoral Cuts][5] Adequate bone cuts with proper alignment are an essential step of this technique. ![Figure][3] [Step 4: Posteromedial Capsulotomy][6] 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. ![Figure][3] ![Figure][3] ![Figure][3] [Step 5: Pie-Crusting of the sMCL][7] Perform pie-crusting followed by serial manipulations in a controlled manner to avoid overrelease of the sMCL. ![Figure][3] ![Figure][3] [Step 6: Flexion Gap Balancing][8] This is a key step for proper balancing, femoral sizing, rotation, lateralization, and patellofemoral tracking. ![Figure][3] ![Figure][3] [Results][9] 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. ![Figure][3] [What to Watch For][10] [Indications][11] [Contraindications][12] [Pitfalls & Challenges][13] [1]: #sec-10 [2]: #sec-11 [3]: pending:yes [4]: #sec-12 [5]: #sec-13 [6]: #sec-14 [7]: #sec-15 [8]: #sec-16 [9]: #sec-17 [10]: #sec-18 [11]: #sec-19 [12]: #sec-20 [13]: #sec-21