Alterations in the patella after a high tibial or distal femoral osteotomy.

Knee osteotomies realign the knee in an attempt to better distribute forces across the knee. The anatomic and physiologic function of the extensor mechanism, which includes the quadriceps tendon, patella, and patella ligament, may be altered during this procedure. An understanding of these changes is important especially when additional surgery becomes necessary, such as a conversion to a total knee arthroplasty. The current authors discuss patella mechanics and changes in the patella associated with osteotomies about the knee and the influence on normal patella biomechanics. Although patella changes are uncommon after a distal femoral osteotomy, poor total knee arthroplasty outcomes after a high tibial osteotomy attributable to patella alterations exist. Surgical technique during the primary high tibial osteotomy and the conversion to the total knee arthroplasty can reliably improve the final outcome. Rigid internal fixation with early knee mobilization after high tibial osteotomy reduces the incidence of patella baja and improves total knee arthroplasty outcome after a high tibial osteotomy, whereas while patella changes after a distal femoral osteotomy are minimal and largely ignored.