Case: Congenital aplasia or hypoplasia of the patella by itself is a rare condition; to our knowledge, it has been associated with aplasia of the quadriceps mechanism only 3 times in the literature. We describe a 5-year-old boy who had bilateral fixed flexion deformity of the knee as well as bilateral hypoplasia of the patella and quadriceps mechanism; he never had been able to stand upright and walk. We present the clinical and radiographic features, the surgical details, and the successful outcome after treatment. Conclusion: Corrective femoral osteotomies with soft-tissue reconstruction to provide active knee extension provided a satisfactory outcome. At the last follow-up, the child was walking without support and had good active knee extension.