Operative Treatment of Patellofemoral Instability: Osteotomies for Torsional and Coronal Malalignment

Patellofemoral instability (PFI) is a prevalent orthopedic issue that leads to significant morbidity and functional limitation. It has a notable incidence, specifically higher amongst adolescent females, and a recurrence rate ranging from 17% to 33%. Recurrent PFI significantly increases the risk of degenerative changes and early-onset osteoarthritis. Patients with multiple risk factors have a remarkably increased rate of recurrence, and thus identifying and managing anatomical risk factors is an effective strategy for patients. These include: trochlear dysplasia, patella alta, increased tibial tubercle-to-trochlear groove (TT-TG) distance, increased femoral anteversion, external tibial torsion, and valgus limb alignment. This study outlines a comprehensive evaluation and surgical approach focusing on PFI associated with torsional or coronal malalignments. The evaluation includes a detailed patient history, clinical examination, and diagnostic imaging. Surgical interventions are selected based on an algorithmic approach tailored to the specific pathoanatomy of the instability, focusing on both bony and soft-tissue procedures. Surgical techniques for addressing PFI in the presence of malalignment include proximal and distal bony procedures. Specific techniques detailed in this study include femoral torsional osteotomy over an intramedullary nail, distal femur opening and closing wedge osteotomies, and torsional tibial osteotomies fixated with an intramedullary nail or plate.