Soft Tissue Surgical Technique for Obligate Dislocation of the Patella.

Abstract

Background: Obligate dislocation of the patella (ODP) is a subtype of congenital disorders and dislocations of the patella. Severity of the condition varies; symptoms range from minor disabilities to impaired ambulation. Definitive treatment for ODP is surgery, with the choice of surgical procedure determined by skeletal maturity.

Case series: This report documents a soft tissue surgical correction for 2 patients with ODP using (1) lateral release of the retinaculum, (2) Z-lengthening of the quadriceps tendon, (3) patellar tendon split transfer (medial side only), and (4) vastus medialis oblique muscle advancement. Patient 1 is a 7-year-old skeletally immature male who experienced complete lateral dislocation of the right patella with flexion. The patient was unable to play sports without falling and without constant patellar dislocation. Patient 2 is a 7-year-old skeletally immature male with Down syndrome who presented with a right laterally dislocating patella with flexion and a 15° flexion contracture of the knee. The patient was unable to ambulate and-according to his parent-would "hit the side of his patella" to center it on his knee to provide stability and permit weight-bearing in a standing frame. After surgery and recovery, both patients reached full weight-bearing without dislocation. Patient 1 plays sports for the first time and has a range of motion of 165°. Patient 2 can stand with stability, continues to work on gait training, and has a range of motion of 160°.

Conclusion: This combined surgical approach mitigates patellar tilt, knee flexion contracture, and recurrent instability, offering a reproducible option for improving stability, tracking, and long-term function in complex patellofemoral pathology.