Surgical correction of limb malalignment for instability of the patella: a comparison of 2 techniques.

Background: Although patients considered "successful" at longer-term follow-up no longer exhibited patellar instability, those with more severe malalignment issues had other, gradually worsening symptoms such as activity-related pain, crepitation, swelling with activities, and pain with weather changes.

Hypothesis: Improvement of patellar tracking by correction of the tubercle-sulcus angle and related ligament deficiencies will result in good to excellent results, regardless of the technique employed.

Study Design: Cohort study; Level of evidence, 3.

Methods: Twenty-five patients with dislocating patellae and significant lower leg deformity were treated; 12 patients (group 1) underwent a derotational high tibial osteotomy and 13 patients (group 2) underwent an Elmslie-Trillat-Fulkerson proximal-distal realignment. All were prospectively evaluated a minimum of 24 months postoperatively with a physical examination, validated outcome questionnaires, radiographs, and computerized axial tomography scans. Postoperative 3-dimensional bilateral gait analyses were performed on all subjects walking on a 3-dimensional force treadmill to measure stance kinematics, foot progression angle, knee flexion, knee valgus-varus, hip flexion, and patella angle. Contralateral limbs with similar preoperative alignment were used as controls.

Results: Group 1 patients significantly improved over their preoperative status in all primary subjective and functional outcome parameters, and were significantly better than group 2 patients. Group 2 patients improved, but not to the degree of group 1 patients. Gait analysis revealed group 1 patients had more symmetrical gait patterns, with less variability and less compensatory gait changes, than group 2 patients.

Conclusion: The original hypothesis proved to be incorrect. The simultaneous correction of ligament imbalance, excessive tubercle-sulcus angle, and lower limb torsional deformity produced significantly better results than conventional proximal-distal realignment.