Exploration of patellofemoral pain and musculoskeletal characteristics in pubertal female dancers: a 12-month follow-up.

The aim of the present study was to examine the prevalence and associated musculoskeletal features of patellofemoral-pain (PFP) in pubertal female dancers at baseline and 12-months later. Thirty-four female dancers (aged 11.9 ± 2.5 yrs, with Tanner stages 3-5 of 68.8% for breasts and 74.2% for pubic at the baseline) were assessed for anthropometric measurements, tibial bone strength, joint ROM, patellar-tendon structure, muscle strength, and were clinically examined by an orthopaedic physician for PFP. At the baseline, 50% suffered from PFP. At the follow-up, 26.5% remained healthy without PFP; 20.6% recovered; 23.5% developed PFP; and 29.4% remained with PFP. PFP*time interaction was found for tibial bone strength (F_(3,30) = 16.534, p < .001). In tendon structure (echo-type III), joint ROM (en-pointe and hip external rotation) and muscle strength (knee flexors, knee extensors and hip abductors), Kruskal -Wallis test showed significantly different improvement/deterioration (from pre to post) between healthy-dancers, recovered-dancers, developed-PFP dancers and dancers that remained with PFP (p < 0.05). A relatively high prevalence of dancers suffered from PFP at both baseline and follow-up, with few having recovered. In dancers that developed PFP and those that remained with PFP, reduced tibial bone strength, alternated tendon structure, increased joint ROM, and reduced muscle strength were seen, compared to their healthy or recovered counterparts.