Tibial Tubercle Osteotomy to Aid Exposure for Revision Total Knee Arthroplasty

Introduction A tibial tubercle osteotomy can provide reliable and safe exposure during revision total knee arthroplasty with a high union rate, low complication rate, and predictable outcomes. Indications & Contraindications Step 1 Preoperative Planning Figs 1-A through 2-B Determine the need for an extensile approach on the basis of the preoperative knee range of motion; position of the patella; bone quality; medical comorbidities; and cement mantle, tibial keel or stem, and thickness of the anterior tibial cortex. Step 2 Incision and Arthrotomy Create full-thickness subcutaneous flaps and perform a medial parapatellar arthrotomy with complete synovectomy and careful excision of scar tissue from the medial and lateral gutters. Step 3 Incision Extension and Preparation for Tibial Tubercle Osteotomy Figs 3 and 4 Videos 1 2 and 3 Extend the skin and subcutaneous dissection distal to the tibial tubercle and mark the chevron osteotomy using electrocautery. Step 4 Tibial Tubercle Osteotomy Fig 5 Videos 4 and 5 Perform the osseous cut for the tibial tubercle osteotomy with a thin saw blade in a medial-to-lateral direction, such that the fragment hinges on the lateral soft tissue and musculature. Step 5 Revision Total Knee Arthroplasty Videos 6 and 7 With the knee maximally flexed and lateral subluxation of the extensor mechanism, for full visualization of the femoral and tibial components, remove the components and perform the knee revision. Step 6 Preparation for Insertion of Tibial Component The final tibial component should have a diaphyseal stem long enough to bypass the distal extent of the tibial tubercle osteotomy by at least 2 cortical diameters. Step 7 Trialing and Insertion of Final Tibial Component Figs 6 and 7 Videos 8 9 and 10 When cementing the final tibial component, take care to remove cement anterior to the tibial stem that would otherwise impede complete reduction of the osteotomy fragment and interfere with osseous union at the osteotomy site. Step 8 Reduction of Tibial Tubercle Osteotomy Fragment Figs 8 and 9 Videos 11 12 and 13 Manually position the osteotomized bone fragment over the tibia and obtain an anatomic reduction either freehand or using bone clamps, depending on the soft-tissue tension. Step 9 Fixation of Tibial Tubercle Osteotomy Fragment Video 14 Obtain rigid fixation with a 6.5-mm screw proximally and 2 sets of doubled-over 18-gauge wires distally. Step 10 Stressing the Osteotomy Site and Wound Closure Figs 10 11 and 12 Videos 15 and 16 Stress the osteotomy site by flexing the knee 90°, deflate the tourniquet, place a drain if needed, and close. Step 11 Postoperative Restrictions and Protocol Figs 13-A and 13-B Allow weight-bearing as tolerated and a 0° to 90° range of motion in a hinged knee brace. Results Tibial tubercle osteotomy to aid in exposure during revision total knee arthroplasty has been reported to yield favorable outcomes in the orthopaedic literature7-18. Pitfalls & Challenges