EXTERNAL TIBIAL TORSION - AN UNDERRECOGNIZED CAUSE OF RECURRENT PATELLAR DISLOCATION

Seventeen patients (18 knees) with recurrent patellar dislocation were identified with increased quadriceps angles secondary to excessive is olated external tibial torsion, Traditional realignment procedures att empted in these knees were unsuccessful because of failure to align th e biomechanical axis of the extensor mechanism, Derotational osteotomi es of the tibia just proximal to the patella tendon insertion were use d to reduce the quadriceps angle to within normal limits to improve th e biomechanics of the extensor mechanism, Seventeen (94%) knees were a vailable for clinical and subjective followup at an average of 25 mont hs (range, 1-3.2 years), Overall, 13 of the 17 knees were graded as go od to excellent (76%), Five of the 17 patients also had well establish ed anterior knee pain in addition to recurrent dislocation and were tr eated with a combined derotational and Maquet type osteotomy, with 4 p atients obtaining a good to excellent result, Knees that subjectively and functionally demonstrated less painful symptoms preoperatively wer e associated with excellent results. Poor outcomes were associated wit h knees that were operated on multiple times.