Tibial Tubercle Osteotomy to Aid Exposure for Revision Total Knee Arthroplasty.

Abstract

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. 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. 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. Extend the skin and subcutaneous dissection distal to the tibial tubercle and mark the chevron osteotomy using electrocautery. 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. 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. 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. 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. 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. Obtain rigid fixation with a 6.5-mm screw proximally and 2 sets of doubled-over 18-gauge wires distally. Stress the osteotomy site by flexing the knee 90°, deflate the tourniquet, place a drain if needed, and close. Allow weight-bearing as tolerated and a 0° to 90° range of motion in a hinged knee brace. Tibial tubercle osteotomy to aid in exposure during revision total knee arthroplasty has been reported to yield favorable outcomes in the orthopaedic literature^7-18.