title: Patellofemoral pain syndrome: evaluation of location and intensity of pain.
abstract: OBJECTIVE
  To identify the sites and intensity of pain in patients with patellofemoral pain syndrome.
  
  
  METHODS
  A prospective cohort study was conducted at an academic sports medicine practice in Boston, Massachusetts. All patients met inclusion criteria and were enrolled and evaluated during the study time frame. A single sports medicine orthopaedic surgeon examined a consecutive sample of patients with patellofemoral pain not explained by one of several well-defined anterior knee pain diagnoses. The study group consisted of 100 patients (75 females, 25 males) with median age of 14 years. Eleven discrete locations were palpated for tenderness. Hamstring tightness was evaluated by measuring the popliteal angle. Patients reported intensity of pain using a 0- to 9-point ordinal scale. Regression and nonparametric statistical methods were used.
  
  
  RESULTS
  The most common site of pain was the patella during anterior-posterior compression (90 patients), followed by the distal pole of the patella, the medial plica, and the nonarticular medial femoral condyle. Median "worst pain" intensity was 6 out of a possible 9. The most common site of "worst pain" was also the patella in compression (63 patients). Median duration of symptoms was 10 months, with an interquartile range of 3 to 20 months. Pain intensity was inversely correlated with duration of symptoms (P < 0.01).
  
  
  CONCLUSIONS
  In these patients with patellofemoral pain syndrome, the major source of pain was the patella subchondral bone.
authors.affiliation: Department of Orthopaedic Surgery, Division of Sports Medicine, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA. peter.gerbino@childrens.harvard.edu
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gerbino
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Griffin
authors.forename: Pierre A
authors.initials: PA
authors.lastname: d'Hemecourt
authors.forename: Thomas
authors.initials: T
authors.lastname: Kim
authors.forename: Mininder S
authors.initials: MS
authors.lastname: Kocher
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Micheli
mesh_terms: D000293:Adolescent; D018771:Arthralgia / Q000175:diagnosis*; D017760:Bone Malalignment / Q000150:complications; D015331:Cohort Studies; D005260:Female; D005269:Femur / Q000293:injuries; D006801:Humans; D007593:Joint Instability / Q000150:complications; D007717:Knee; D016014:Linear Models; D008297:Male; D010147:Pain Measurement; D010329:Patella / Q000293:injuries; D011446:Prospective Studies; D013577:Syndrome