Revision surgery for failed medial patellofemoral ligament reconstruction results in better disease-specific outcome scores when performed for recurrent instability than for patellofemoral pain or limited range of motion.

PURPOSE: Medial patellofemoral ligament reconstruction (MPFL-R) is an important treatment for recurrent patellar instability. Although complications such as redislocation, patellofemoral pain (PFP) and restricted knee range of motion have been reported, few studies have investigated the results of revision surgery for failed MPFL-R. Thus, the aim of this study was to determine the results of the tailored revision surgery after considering the cause of the reconstruction failure. MATERIALS AND METHODS: Between 2015 and 2019, 28 patients (male/female 9/19; age 26.2 ± 6.4 years) underwent revision surgery for failed MPFL-R. The patients were grouped into the "recurrent instability" (SG1) group and "PFP" and/or "restricted range of motion" (SG2) group. Preoperatively, the clinical data, anatomical risk factor profile, and position of the femoral MPFL tunnel were determined for each patient. The Banff Patella Instability Instrument 2.0 (BPII 2.0) and numerical analogue scale (NAS 0-10) were administered preoperatively and at the final follow-up for the subjective assessment of the PFP and knee joint function. RESULTS: Overall, the BPII 2.0 score improved from 28.8 ± 16.6 points preoperatively to 68.0 ± 22.7 points (p < 0.0001) postoperatively. SG1 exhibited an increase in the BPII 2.0 score from 28.9 ± 20.2 points to 75.7 ± 23 points (p < 0.0001). PFP decreased from 6.8 ± 2.4 to 1.6 ± 1.9 (p < 0.0001), while the knee joint function increased from 4.3 ± 2.5 to 8.8 ± 1.6 (p < 0.0001). In SG2, the BPII 2.0 score increased from 28.7 ± 12.6 points preoperatively to 57.7 ± 19.7 points (p = 0.0002) postoperatively and was thus significantly lower than that in SG1 (p = 0.038). The intensity of PFP decreased from 6.6 ± 3.0 preoperatively to 2.1 ± 1.9 postoperatively (p = 0.0006), while the subjective knee joint function improved from 3.2 ± 1.4 preoperatively to 7.6 ± 2.3 postoperatively (p < 0.0001). The differences between the groups were not significant. CONCLUSION: Tailored revision surgery for failed MPFL-R significantly improves the patient-reported disease-specific quality of life. The study results indicate that patients undergoing revision surgery as a consequence of patellar redislocation appear to benefit more from revision surgery than those patients undergoing revision due to postoperative PFP and/or a limited knee joint range of motion. LEVEL OF EVIDENCE: Level IV.

Patient-Reported Outcomes After Revision Surgery for Failed Medial Patellofemoral Ligament Reconstruction: A Matched-Pair Analysis Including Correction of Predisposing Factors.

BACKGROUND: Complications and the need for revision surgery after medial patellofemoral ligament reconstruction (MPFLR) are evident in the current literature. However, there is a shortage of clinical data evaluating the results of revision surgery in individual patients after failed MPFLR. PURPOSE: To investigate the results of tailored revision surgery for failed MPFLR, including the correction of predisposing factors. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between August 2015 and March 2019, 25 patients (male:female, n = 9:16; mean ± SD age, 25.9 ± 6.5 years) underwent revision surgery for failed MPFLR (study group). The Banff Patella Instability Instrument 2.0 (BPII 2.0) and a numerical analog scale (0-10) for patellofemoral pain and subjective knee joint function were used to assess patient-reported quality of life before and after revision surgery. The control group of 50 patients (male:female, n = 18:32; age, 22.8 ± 4.3 years) who underwent identical patellar-stabilizing procedures was matched 1:2 by the surgical procedure, predisposing factors, sex, age, and follow-up time. RESULTS: Evaluation was performed postoperatively at a mean 27.8 ± 14.0 months (range, 12-54 months) in the study group and 26.1 ± 11.2 months (range, 12-56 months) in the control group (P = .55). The BPII 2.0 score increased from 28.6 ± 17.9 points to 68.7 ± 22.3 points (P < .0001) in the study group and from 43.8 ± 22.5 points to 75.5 ± 21.4 points (P < .0001) in the control group from preoperatively to postoperatively, respectively. Before revision surgery, the BPII 2.0 scores in the study group were significantly inferior to those in the control group (P = .0026). At the final follow-up, the BPII 2.0 score in the study group was not significantly lower (P = .174), and a similar number of patients in the study group and the control group achieved the minimally clinically important difference (P = .49). Patellofemoral pain and subjective knee joint function improved significantly in both groups (P < .0001, P < .0001), without any significant difference between them at the final follow-up (P = .85, P = .86). CONCLUSION: Revision surgery for MPFLR failure, including the correction of major anatomic risk factors, yielded a significant improvement in patient-reported quality-of-life outcome measures. Patients with failed MPFLR, however, were significantly more restricted before revision surgery than patients without previous interventions when evaluated with the BPII 2.0.