[Reconstruction of the medial patellofemoral ligament using autologous gracilis tendon in an implant-free technique on the patellar side]

Midterm Results After Isolated Medial Patellofemoral Ligament Reconstruction as First-Line Surgical Treatment in Skeletally Immature Patients Irrespective of Patellar Height and Trochlear Dysplasia

BACKGROUND

Medial patellofemoral ligament reconstruction in skeletally immature patients who experience lateral patellar dislocation has been reported to yield good results. Whether bony abnormalities such as patellar height and trochlear dysplasia should be addressed additionally is a topic of discussion.

PURPOSE

To evaluate patient-reported outcomes and redislocation rates after isolated medial patellofemoral ligament reconstruction as first-line surgical treatment for lateral patellar dislocation in skeletally immature patients. Further, to analyze epidemiological, intraoperative, and radiographical factors influencing redislocation and clinical outcome.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Prospectively collected data were retrospectively analyzed for adolescent patients younger than 16 years who underwent medial patellofemoral ligament reconstruction between 2014 and 2018. Inclusion criteria were isolated medial patellofemoral ligament reconstruction with gracilis tendon and availability of accurate pre- and postoperative radiographs with the presence of open physes. The patients were questioned regarding further surgery, redislocation, and clinical outcomes using the Tegner Activity Scale, International Knee Documentation Committee (IKDC) Subjective Knee Form, Lysholm score, and Kujala score. The influence of diverse epidemiological, intraoperative, and radiographical parameters on the redislocation rates and clinical outcome was analyzed.

RESULTS

A total of 54 medial patellofemoral ligament reconstructions (49 patients) met the inclusion criteria. After 4.3 ± 1.7 years (range, 2.0-7.3 years), 45 reconstructions (83.3%) in 41 patients were available for follow-up. The distribution of trochlear dysplasia was as follows: type A and B, 19 cases (42.2%) each; type C, 6 cases (13.3%); and type D, 1 case (2.2%). Patellar redislocation occurred in 3 patients (6.7%). The mean Tegner, subjective IKDC, Lysholm, and Kujala scores at follow-up were 6.3 ± 1.6 (range, 3-9), 93.6 ± 8.8, 95.9 ± 7.4, and 97.9 ± 7.1, respectively. Patellar height and trochlear dysplasia had no influence on redislocation or clinical scores. The Lysholm score was lower in knees with intraoperative retropatellar chondral lesion grade ≥III versus grade <III (89.0 ± 19.2 vs 96.9 ± 3.6, respectively; P = .023); likewise, the Kujala score was lower in knees that were grade ≥III versus grade <III (90.0 ± 19.7 vs 98.1 ± 2.1, respectively; P = .015).

CONCLUSION

Isolated medial patellofemoral ligament reconstruction as first-line surgical treatment in skeletally immature patients yields excellent midterm results, irrespective of patellar height and trochlear dysplasia. Redislocation still occurs in a certain number of patients, and a higher degree of retropatellar chondral lesion is a predictor for a worse clinical outcome.

Midterm Results after Implant-Free Patellar Fixation Technique for Medial Patellofemoral Ligament Reconstruction

Problems and complications concerning the patellar fixation in medial patellofemoral ligament reconstruction (MPFLR) have been reported. The purpose of this retrospective study was to systematically analyze the surgical technique for MPFLR with a V: -shaped patellar bonetunnel for implant-free fixation of an autologous gracilis tendon, allowing early functional rehabilitation, regarding restoration of the patellofemoral stability, patient satisfaction, return to sports, and technique-specific complications. In 2010, 128 cases of consecutive isolated MPFLR were performed. All these cases were included. After a minimum follow-up of 3 years, 104 cases were retrospectively analyzed (follow-up: 81.3%) with regard to redislocation, subjective functional outcome (Tegner's score and sports level compared with preoperative level), patient satisfaction, revision surgery, and technique-specific complications. After a follow-up of 45.7 ± 3.2 months, 101 of 104 cases (97.1%) showed no redislocation. Mean Tegner's score was 5.1 ± 1.8 (range, 2-9). A total of 61.5% patients reported about a higher sports level compared with their preoperative level. The patient satisfaction was high with 94.2%. In two cases (1.9%), technique-specific problems occurred as the bone bridge of the V: -shaped tunnel was insufficient due to a malpositioning of the aiming device. No further technique-specific problems occurred and no revision surgery was necessary during the observational period. The presented surgical technique is safe and it reliably restores the patellofemoral stability, with a low rate of redislocations, an excellent subjective functional outcome, and a high-patient-reported satisfaction. No major technique-specific complications occurred.