From general to precision rehabilitation: a systematic review of VMO-Targeted versus general quadriceps strengthening in patellofemoral dysplasia

To systematically evaluate the safety of generalized quadriceps training versus the efficacy of individualized, vastus medialis obliquus (VMO)-targeted rehabilitation in patients with radiologically confirmed patellofemoral dysplasia (PFD). Systematic review conducted in accordance with the PRISMA guidelines. PubMed, Cochrane Library, Embase, and Web of Science were searched from inception to December 2024. Randomized controlled trials (RCTs) and prospective cohort studies involving patients with radiologically confirmed PFD, comparing quadriceps training interventions, and reporting objective patellar stability outcomes. Twelve studies (7 RCTs, 5 prospective cohorts) involving 1,876 participants were included. Generalized quadriceps training significantly increased the risk of patellar instability by 2.1- to 4.5-fold compared to VMO-targeted rehabilitation combined with hip abductor strengthening. The highest risk (4.5-fold) was observed with deep flexion exercises (> 60°) in patients with severe trochlear dysplasia (Dejour types C/D), consistent with biomechanical models of elevated joint contact pressures. In contrast, VMO-targeted training within a 0°–30° arc reduced patellar lateralization by a mean of 1.9 mm. Combined VMO and hip abductor strengthening yielded superior outcomes, with a 2.1 mm reduction in patellar lateralization and a 2.4° reduction in dynamic knee valgus. This efficacy is attributed to the VMO's synergy with medial stabilizers and the correction of proximal hip deficits. A risk-stratification framework was developed to guide intervention selection. Moderate-certainty evidence suggests that generalized quadriceps training may increase patellar instability risk in patients with radiologically confirmed PFD, particularly in those with severe trochlear dysplasia. Precision rehabilitation targeting the VMO-hip synergy is preferred, as it demonstrates meaningful improvements in patellar stability. The proposed risk-stratification framework provides a practical tool for individualized care.