Self-reported Recovery is Associated With Improvement in Localized Hyperalgesia Among Adolescent Females With Patellofemoral Pain: Results From a Cluster Randomized Trial

OBJECTIVES: Adolescent females with patellofemoral pain (PFP) have localized (around the knee) and distal (tibialis anterior muscle) hyperalgesia assessed by decreased pressure pain thresholds (PPT). This may have implications for treating PFP as both localized and central pain mechanisms may contribute to the manifestations of pain. The objective of this study was to compare the change in localized and distal hyperalgesia among female adolescents with PFP deeming themselves recovered compared with those not recovered 3 months after patient education with or without exercise therapy.

METHODS: This is an ancillary analysis of a cluster randomized controlled trial investigating the effect of patient education with or without exercise therapy on self-reported recovery in 121 adolescents with PFP. PPTs were measured at 4 sites around the knee and on tibialis anterior in a random subsample of 57 female adolescents. Changes in localized and distal hyperalgesia from baseline to follow-up were compared with self-reported recovery. Adolescents were categorized as recovered if they rated themselves as "completely recovered" or "strongly recovered" on a 7-point Likert scale.

RESULTS: Thirty-nine adolescents (68%) were available for follow-up at 3 months and 10 adolescents reported being recovered. Recovered adolescents had a 68 kPa (95% CI, 1, 136; P=0.047) larger improvement in PPT around the knee and a 76 kPa (95% CI, -29, 181; P=0.16) nonsignificant improvement in PPT on the tibialis anterior compared with adolescents not recovered.

CONCLUSIONS: Female adolescents with PFP who rated themselves as recovered had a larger reduction in localized hyperalgesia compared with those not recovered.