Lower-extremity asymmetry and patellofemoral pain in young female dancers: A 2-year follow-up.

Abstract

Patellofemoral pain (PFP) is a prevalent injury in young dancers, with low recovery rates. This study aimed to assess PFP in young female dancers over a 2-year period while examining associations between lower-limb asymmetry and PFP. Thirty-two female dancers (aged 13.6 ± 2.9 years) were clinically examined for PFP at the baseline, 12 months later (first follow-up), and 24 months later (second follow-up). Dancers were also assessed for anthropometric measurements, joint range of movement (ROM), and muscle strength. PFP was identified in 46.9%, 53.1%, and 46.9% of the dancers at the three time points, respectively. When comparing the baseline to the second follow-up, 21.9% of the dancers had recovered, 21.9% had developed PFP, and 25.0% had remained with PFP. Only 31.3% had remained healthy throughout this period. Examining muscle-strength-asymmetry in the four groups of dancers, significant interactions (time × group) were found for ankle plantar-flexor, knee extensor, hip abductor, and hip extensor muscle strength (p < .001), indicating that dancers in the developed-PFP or remained-PFP groups had greater muscle-strength-asymmetry at baseline than the recovered or healthy groups. Significant differences in the prevalence of asymmetry between the four groups were found for joint ROM (ankle en-pointe, hip abduction, hip external rotation, and hip internal rotation) (p < .05); and significant differences in the prevalence of asymmetry between the three time points were found for joint ROM (ankle en-pointe, ankle dorsiflexion, hip extension, hip abduction, and hip external rotation) (p = .05). A high prevalence of dancers had PFP, with a limited prevalence of recovery. Dancers who developed PFP or remained with PFP had greater muscle strength and joint ROM asymmetry than their healthy or recovered counterparts. Screening for and addressing asymmetries in strength measures may modify the risk for PFP in dancers.