Clinical outcomes of femoral bone tunnel fixation and onlay fixation techniques for medial patellofemoral ligament reconstruction: a systematic review.

BACKGROUND: Medial patellofemoral ligament reconstruction (MPFLR) for treatment of recurrent patellofemoral instability yields excellent outcomes and has been shown to be safe. Femoral fixation can be performed using various methods, however the role of onlay techniques when compared to bone tunnels for femoral fixation during MPFLR has not been fully described in adults. AIM: To describe patient satisfaction and success of bone tunnel and onlay fixation techniques in MPFLR. METHODS: A systematic search of the literature was performed in May 2026. Studies reporting outcomes of isolated MPFLR for patellar instability in skeletally mature patients, including surgical technique, complications, and recurrence were included. Studies where patients had previous ipsilateral knee surgery, concomitant additional procedures, medial patellofemoral ligament (MPFL) repairs, congenital disease, case reports, and sample sizes smaller than 10 were excluded. RESULTS: In this review, 80 studies were included, with a total of 4100 patients (60.8% female/39.2% male). The femoral bone tunnel group was composed of 3851 patients (93.9%) while the onlay fixation group included 249 patients (6.1%). The mean postoperative Kujala score for the bone tunnel group was 87.9 (95%CI [86.7, 89.0]). The mean postoperative Kujala score for the onlay group was 91.4 (95% CI [88.6, 94.1]). Mean redislocation events were 2.0% for the tunnel group (95%CI [1.3%, 2.9%]) and 1.7% in the onlay group (95%CI [0.47%, 3.78%]) CONCLUSION: Onlay fixation techniques for femoral tunnel fixation during MPFLR are much less commonly reported; however, these appear to be comparable with bone tunnel techniques with good outcomes and low rates of redislocation. Onlay fixation options can be considered a safe alternative in cases when bone tunnels may not be possible. LEVEL OF EVIDENCE: I, Systematic review.