Purpose
Medial patellofemoral ligament (MPFL) reconstruction usually involves hamstring autografts and is associated with donor-site morbidity. The use of polyester high-strength suture tape (FiberTape®, Arthrex) and knotless SwiveLock® anchors (Arthrex) in MPFL reconstruction is less invasive and significantly improves patients’ quality of life and post-operative knee outcome measures. The purpose of this study was to investigate the return to pre-injury sports (RTS) after MPFL reconstruction using this technique for patellar instability.
Patients and Methods: This was a retrospective analysis of the 94 knees of 65 patients (16 males and 49 females, mean age; 19.9±9.8 years) surgically treated for lateral patellar instability between 2016 and 2020. All patients underwent MPFL reconstruction using FiberTape with knotless SwiveLock anchors and had a minimum 2-year follow-up. Demographic data, pre-operative sports activity level, time from surgery to RTS, Knee Injury and Osteoarthritis Outcome Scale (KOOS) scores, recurrent apprehension and re-dislocations postoperatively were collected. Tibial tuberosity to trochlear groove (TT-TG) distance on CT, patellar height (Insall-Salvati ratio, ISR) and trochlear dysplasia (trochlear depth) on lateral plain X-ray were measured. Factors associated with KOOS subscale scores were investigated using liner regression analysis.
Results
There were no patients with patella re-dislocation, however, 3 knees showed a positive apprehension sign at final follow-up. At pre-operative activity level, 28 of 65 patients played sports at a competitive level, 20 patients at a recreational level, and 17 did not play at all. The rate of RTS at competitive level was 92.6% (26 of 28 patients), and the mean time from surgery to RTS was 6.0±2.8 (3-12) months. For those at the recreational level RTS was 100%, and 5.6±2.3 (2-11) months, respectively. At the competitive level, the liner regression analysis showed lower KOOS sports activities scores were significantly related to higher Body mass index (BMI) (B=-2.49, p=0.00), bilateral case (B=-11.06, p=0.01) and higher ISR (B=-40.8, p=0.00). There was no significant correlation between KOOS sports activities score and age, gender, TT-TG distance or TD.
Discussions: The MPFL reconstruction using FiberTape and SwiveLock anchors was safe and effective for ability to RTS. The overall rate of RTS was 92.9%. Higher BMI, bilateral cases and patella alta resulted in lower KOOS sports activities scores in competitive athletes.