Medial patellofemoral ligament reconstruction using semitendinosus tendons: polyester suture augmentation versus nonaugmentation.

BACKGROUND: The comparative clinical outcome of medial patellofemoral ligament reconstruction (MPFLR) using semitendinosus tendons with and without polyester suture augmentation for recurrent patellar instability is unknown.

HYPOTHESIS: Medial patellofemoral ligament reconstruction with polyester suture augmentation will yield better results than MPFLR without augmentation for recurrent patellar instability in adults.

STUDY DESIGN: Randomized controlled trial; Level of evidence, 2.

METHODS: One hundred patients with recurrent patellar instability receiving MPFLR using semitendinosus tendons were randomly divided into 2 groups either with or without polyester suture augmentation. Tibial tubercle transfer was performed in most cases. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patellar glide test was performed before surgery, immediately after MPFLR during the operation, and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee, Lysholm, and Kujala rating scales. Redislocation or multiple episodes of patellar instability were considered failures.

RESULTS: Forty-two patients in the augmentation group and 43 patients in the nonaugmentation group were followed for 5 years and received complete serial CT examinations and functional evaluations. The correction of the static patellar position deteriorated over time in the nonaugmentation group but not in the augmentation group. The results of the passive patellar glide test indicated stable patellae in all patients immediately after MPFLR and more stable patellae in the augmentation group at each follow-up point. Functional evaluations at 2 and 5 years revealed statistically significant superior results in the augmentation group. Finally, no patient in the augmentation group and 2 (4.7%) in the nonaugmentation group experienced episodes of redislocation, and 1 patient (2.4%) in the augmentation group and 8 (18.6%) in the nonaugmentation group experienced multiple episodes of patellar instability, resulting in failure rates of 2.4% and 23.3% in the augmentation group and nonaugmentation group, respectively (P = .004).

CONCLUSION: Medial patellofemoral ligament reconstruction with polyester suture augmentation results in better static patellar position, dynamic stability, and functional outcome than without augmentation in the treatment of recurrent patellar dislocation in adults.