Background: Trochlear dysplasia is an important etiological factor for the development of patellofemoral instability. Because a dislocation of the patella as a result of trochlear dysplasia results in a traumatic disruption of the medial patellofemoral ligament (MPFL), a combined trochleoplasty and patellofemoral ligament reconstruction appears to be the most appropriate procedure to treat patients with severe trochlear dysplasia.
Hypothesis: Combined trochleoplasty and anatomic reconstruction of the MPFL will prevent redislocations of the patella and will lead to improved knee function.
Study design: Case series; Level of evidence, 3.
Methods: Twenty-three consecutive patients (26 knees) with patellofemoral instability and severe trochlear dysplasia underwent combined trochleoplasty and anatomic reconstruction of the MPFL. Preoperative radiographic examination included anteroposterior and lateral views to assess patella alta. Magnetic resonance imaging was performed to evaluate trochlear dysplasia and the tibial tubercle-trochlear groove (TT-TG) distance. Evaluations included the detection of cartilage injuries, preoperative and postoperative physical examinations, and scores for the visual analog scale (VAS), Kujala knee function, International Knee Documentation Committee (IKDC), activity rating scale (ARS), and Tegner activity scale.
Results: The mean age at the time of operation was 19.2 years (range, 15.4-23.6 years). The mean follow-up after operation was 2.5 years after surgery (range, 2.0-3.5 years). No recurrent dislocation occurred postoperatively. Kujala scores improved from 79 to 96, IKDC scores from 74 to 90, and VAS scores from 3 to 1. All improvements were highly statistically significant (P < .01). The activity level according to the Tegner activity scale and the ARS decreased but was not statistically significant (P = .06 and P = .21, respectively). There were 95.7% of the patients who were satisfied or very satisfied with the procedure.
Conclusion: Combined anatomic reconstruction of the MPFL and trochleoplasty reliably improved the stability of the patellofemoral joint in patients with severe trochlear dysplasia and no or mild degenerative changes. In addition, the described procedure showed significant improvement of knee function and good patient satisfaction without any episode of redislocations of the patella.
Keywords: medial patellofemoral ligament; patellofemoral instability; trochlear dysplasia.