summary TKA in Patella Baja is characterized by performing a TKA in a patient with a prior high tibial osteotomy that caused lowering of the patella relative to its normal position. Diagnosis can be made with plain radiographs of the knee showing an Insall-Salvati ratio of < 0.8. Treatment of patellar baja in a TKA involves various techniques including lowering the joint line, placing the patellar component superiorly, or performing a tibial tubercle transfer. Etiology Pathophysiology of acquired patella baja common causes include proximal tibial osteotomy login to view 2 more bullets tibial tubercle slide or transfer trauma to the proximal tibia technical error during primary total knee replacement (joint line elevation) ACL reconstruction Associated conditions total knee arthroplasty patella infera is an important consideration when performing total knee arthroplasty login to view 2 more bullets Presentation Symptoms anterior impingement knee pain knee stiffness Physical exam mechanical block to full flexion limited flexion due to patellar impingement on the tibia in extremes of flexion Imaging Radiographs recommended views AP and lateral views of the knee lateral view of the knee in 30 degrees of flexion login to view 3 more bullets findings lateral view in extension login to view 1 more bullet Insall-Salvati ratio of < 0.8 is consistent with patella baja Treatment Nonoperative activity modifications, physical therapy indications login to view 1 more bullet Operative total knee replacement indications login to view 1 more bullet Techniques Total knee arthroplasty in patient with patella baja methods to address patella infera during TKA place patellar component superiorly login to view 5 more bullets lower joint line login to view 8 more bullets transfer tibial tubercle to cephalad position login to view 7 more bullets patellectomy login to view 7 more bullets