Total knee arthroplasty for the treatment of osteoarthritis secondary to bilateral congenital patellar dislocation: A case report and review of the literature.

Congenital patellar dislocation is a relatively rare clinical deformity. In some patients, a delayed diagnosis or lack of early surgical intervention results in permanent patellar dislocation and subsequent knee osteoarthritis. Total knee arthroplasty (TKA) is currently the most effective treatment for end-stage osteoarthritis, but performing surgery in these patients presents notable technical challenges. The current report presents the case of a 60-year-old woman who had been suffering from knee extensor weakness and dysfunction for >50 years, resulting in an active knee extension deficit. The patient experienced a sensation of instability in the knee when going up and down stairs and could only walk short distances without the aid of a cane. These severe symptoms markedly affected daily life. The patient was diagnosed with total knee osteoarthritis (Kellgren-Lawrence grade IV), secondary to congenital patellar dislocation, according to established clinical and radiological criteria, accompanied by valgus deformity and flexion contracture of the knee joint. The patient underwent a staged bilateral TKA. The procedure utilized the standard Insall approach, with bone cuts performed to achieve mechanical alignment and implantation of conventional primary prostheses. Additionally, the pie-crusting technique was employed to release the lateral structures, while the overlap-suturing technique was used to reinforce the medial structures, thereby ensuring proper patellar tracking. At the final follow-up, the patient exhibited satisfactory clinical outcomes, including a pain-free gait, full knee extension and good joint range of motion. Imaging confirmed stable prosthesis alignment with no signs of loosening or patellar subluxation, while dynamic assessment demonstrated excellent patellofemoral joint stability. In conclusion, TKA is the most effective treatment for osteoarthritis caused by congenital patellar dislocation. Through the implementation of the pie-crusting technique and overlap suturing for lateral structural release and medial structural reinforcement, respectively, notable patellar reduction was achieved employing standard prostheses.