Adductor sling and anatomic femoral tunnel fixation both yield high postoperative functional scores after medial patellofemoral ligament reconstruction: A retrospective multicenter study

Abstract

Introduction/Objectives

Adductor sling (AS) and anatomic femoral tunnel (AFT) are femoral-side fixation options for medial patellofemoral ligament reconstruction (MPFLR), but direct comparative evidence remains limited. We hypothesized similar final Kujala scores and similar outcomes regarding redislocation, residual subjective instability, and subsequent ipsilateral knee surgery with both techniques.

Methods

This retrospective multicenter comparative cohort included 84 knees in 78 skeletally mature patients who underwent MPFLR for recurrent lateral patellar instability between 2017 and 2024 (19 AS and 65 AFT cases). Exclusion criteria included previous ipsilateral surgery and concomitant trochleoplasty, corrective femoral osteotomy, or tibial osteotomy other than tibial tubercle osteotomy (TTO). The primary outcome was the final Kujala score. An exploratory parsimonious regression adjusted for age, sex, follow-up duration, and TTO; cluster-robust standard errors accounted for bilateral knees.

Results

The final Kujala score, redislocation, and residual-instability outcomes were available for 80 knees (18 AS and 62 AFT cases). Median follow-up was 35.6 months after AS and 55.6 months after AFT (p < 0.001). Concomitant TTO was more frequent after AFT than AS fixation (66.2% versus 31.6%; p = 0.009). Median Kujala scores were 91.0 and 94.0, respectively, (difference: −3.0; 95% confidence interval [CI]: −8.5 to 2.5; p = 0.456). Redislocation occurred in 0 of 18 AS and 2 of 62 AFT knees (p = 1.000). Residual instability occurred in 6 of 18 (33.3%) and 13 of 62 (21.0%) cases, respectively (risk difference: 12.4%; 95% CI: −8.3% to 36.7%; p = 0.347). No subsequent procedures occurred after AS fixation; four occurred after AFT fixation, including two in the same patient for the same complication. In the parsimonious adjusted model, the mean difference for AS versus AFT was −5.31 points (95% CI: −12.61 to 1.99; p = 0.151).

Conclusion

Both AS and AFT fixation yielded high postoperative functional scores and low redislocation rates. Neither analysis identified a clear between-technique difference in the final Kujala score. Patient-reported residual instability was more common after AS fixation, although the estimate was imprecise and based on a retrospective, nonstandardized assessment. Prospective studies with standardized indications and instability assessments should clarify which patient subgroups benefit from each technique.

Level of evidence

III.