Bilateral rotational osteotomies of the proximal tibiae and tibial tuberosity distal transfers for the treatment of congenital lateral dislocations of patellae: a case report and literature review.

Congenital dislocation of patella (CDP) causes varying degree of disability. Patients may present as late walkers with asymmetric gait, habitual or recurrent dislocators or even non-walkers if the condition is bilateral. Patellar instability is often associated with soft tissue or bony pathology. Soft tissue anomalies include lateral soft tissue contractures, shortened quadriceps as well as vastus medialis dysplasia (abnormal origin and insertion). Bony anomalies include shallow trochlear groove and hypoplastic patella or lateral femoral condyle. Soft tissue etiologies result in an imbalance of the dynamic forces acting on the patella while in bony etiologies the static stabilizers to resist lateral dislocation are compromised. External tibial torsion is an additional etiology, often under diagnosed due to the difficulty in measuring the Q angle of dislocated patella. We report a case of bilateral congenital lateral dislocations of the patellae treated with bilateral tibial rotational osteotomies with an 8 year and a 4 year follow up.