Perform patellar realignment to restore or improve the mechanical alignment of the quadriceps mechanism. Patellar realignment in childhood is complicated by the wide range of pathological elements. Lateral contracture, rotational and angular malalignment, condylar and patellar hypoplasia, muscle hypoplasia, and imbalance may be present either alone or in various combinations. Often realignment requires a combination of procedures, which is best accomplished through a direct anterior longitudinal incision. This allows intraoperative visualization of the pathology and tailoring of the repair to best correct the problems. Make certain at the end of the procedure that with passive flexion and extension of the knee the patella tracts vertically in the midline. Except for transfer of the tibial tubercle, these procedures may be performed in the growing child without the risk of growth arrest.
Lateral contractures are often present in congenital patellar dislocations or those that occur in infancy. In rare cases, very extensive, more proximal release is necessary. In others, a more limited release is adequate. Be aware that lateral release is seldom indicated for most patellar instability cases. Excessive release may cause medial patellar dislocation from the loss of the normal lateral tether.
Medial plication is necessary because of the attenuation of the medial capsule and the meniscofemoral ligament on the undersurface of the vastus medialis oblique muscle that follows acute patellar dislocation. This may be corrected by first reefing the medical capsule and then advancing the VMO over the quadriceps. Avoid overcorrection, a common complication.
Tenodesis of the semitendinosis tendon into the patella creates a check-rein that is very effective in realignment. Often this tenodesis is combined with a lateral release and medial capsular reconstruction.
Tibial Tubercle Transfer
This procedure is most commonly needed for the adolescent with malalignment that can be corrected by a distal procedure. Perform the tibial tubercle rotational transfer through a longitudinal incision to allow correction of associated problems.
Patellar Tendon Hemitransfer
Patellar tendon hemitransfer are no longer done, as the procedure causes secondary problems due to a patellar tilt caused by the operation.