Congenital patellar dislocation is a rare deformity and late presentation is usually with knee osteoarthritis. Total knee arthroplasty (TKA) is also a treatment choice of this rare pathology. There are few cases reported gonarthrosis with congenital patellar dislocation treated with TKA. And there are some contradictions in the written literature. This article presents a case of a 55 years old woman who had left knee pain for 8 years that was worsened in last 2 years with gonarthrosis and congenital patellar dislocation treated by cruciate retaining TKA with proximal and distal patellar alignment without patellar resurfacing. At the final follow-up after 1 year ROM was 5 degrees-100 degrees. There was no patellar maltracking or instability. The Knee Society score and functional scores were 55 and 15 preoperatively, improved to 83 and 55 respectively at the postoperative period. Congenital patella dislocation with gonarthrosis is hard to manage by TKA, but it can be handled with a good pre-operative planning with meticulous attention.