Summary TKA Patellar Maltracking is a common cause of patient dissatisfaction following TKA and is the most common reason for secondary surgery following total knee arthroplasty. Diagnosis is made clinically with a combination of anterior knee pain, patellar subluxation during ambulation, and limitation in knee flexion. Treatment may be nonoperative or operative depending on underlying etiology. Epidemiology Incidence most common reason for secondary surgery following total knee arthroplasty Etiology Causes may be related to prosthetic design extensor mechanism imbalance asymmetric patellar resection malrotation internal rotation of components failure to recognize hypoplastic lateral femoral condyle in valgus knee osteoarthritis leads to internal rotation of the femoral component patellar malpositioning Presentation Symptoms complaints may include feelings of subluxation frank dislocation peri-patellar pain limited flexion Imaging Radiographs recommended views AP used to assess placement of femoral component and Q angle lateral used to assess size and rotation of femoral component tangential used to assess subluxation of patella, placement of patellar component, angle of patellar resection, and patellar tilt findings laterally subluxed patella increased Q angle anterior placement of femoral component asymmetric patellar resection lateral placement of patellar component lateral osteophyte on patella CT best to assess for rotational malalignment Treatment Must appropriately address etiology