Background: Solitary trochleoplasty for recurrent patellar dislocation offers a unique benefit in that it addresses the most important factor in patellar instability: the trochlear dysplasia.
Description: The trochlea is visualized through a lateral arthrotomy of the knee joint. An osteochondral layer is peeled off with curved chisels and extended into the intercondylar notch. A triangular bone block is removed from the subchondral bone to form the new groove. A new groove is begun with a chisel and smoothed with a high-speed burr. Also, the osteochondral layer is thinned out and fixed back transosseously in the new groove with 2 Vicryl (polyglactin) bands. The bone block is used to lengthen the lateral condyle by placing it under the osteochondral layer at the proximal extension of the lateral femoral condyle with an overlap of 1 cm.
Alternatives: Nonsurgical alternatives include a knee or patellar brace, taping of the patella, and physiotherapy for strengthening of the vastus medialis obliquus of the quadriceps muscle. Surgical alternatives include reconstruction of the medial patellofemoral ligament; several femoral and tibial osteotomies, such as rotational osteotomies of the femur and tibia or medialization of the tibial tuberosity; and several soft-tissue interventions, such as medial reefing, relocation of the patellar tendon as described by Goldthwait1, and proximal realignments according to the method described by Insall et al.2 or Green et al.3.
Rationale: Most patients with recurrent patellar dislocation have a dysplastic trochlea4, which is considered to be the primary reason for a recurrence. While interventions such as reconstruction of the medial patellofemoral ligament or femoral and tibial osteotomies also provide stability of the patella, they do not change the most essential factor of the instability-the trochlear dysplasia. The trochleoplasty addresses this underlying condition and reshapes the trochlea.