title: The Tibial Tubercle-Trochlear Groove Distance Is Greater in Patients With Patellofemoral Pain: Implications for the Origin of Pain and Clinical Interventions.
abstract: BACKGROUND
  The distance between the tibial tubercle (TT) and trochlear groove (TT-TG distance) is known to be greater in patients with patellar instability. However, the potential role and prevalence of pathological TT-TG distances in a large cohort of skeletally mature patients with isolated patellofemoral pain (PFP) are not clear.
  
  
  OBJECTIVE
  To determine if the mean TT-TG distance is greater in patients with PFP, who lack a history of patellar dislocations, knee trauma, or osteoarthritis, relative to healthy controls.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  A total of 50 knees (38 patients) with PFP and 60 knees (56 controls) without PFP formed the basis of this study. Magnetic resonance imaging was used to determine the TT-TG distance from 3-dimensional static scans.
  
  
  RESULTS
  The cohort with PFP demonstrated a significantly greater mean TT-TG distance relative to asymptomatic controls (13.0 vs 10.8 mm, respectively; P = .001). Among the cohort with PFP, 15 knees (30%) demonstrated TT-TG distances ≥15 mm, and 3 knees (6%) demonstrated TT-TG distances ≥20 mm.
  
  
  CONCLUSIONS
  Most adult patients with isolated PFP have elevated TT-TG distances compared with controls, which likely contributes to the force imbalance surrounding the knee.
authors.affiliation: Functional and Applied Biomechanics Section, Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Victor R
authors.initials: VR
authors.lastname: Carlson
authors.affiliation: The Orthopaedic Center, Rockville, Maryland, USA.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Boden
authors.affiliation: Functional and Applied Biomechanics Section, Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Aricia
authors.initials: A
authors.lastname: Shen
authors.affiliation: Functional and Applied Biomechanics Section, Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Jackson
authors.affiliation: Department of Radiology and Imaging Sciences, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Yao
authors.affiliation: Functional and Applied Biomechanics Section, Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Frances T
authors.initials: FT
authors.lastname: Sheehan
mesh_terms: D000293:Adolescent; D000328:Adult; D018771:Arthralgia / Q000473:pathology* / Q000503:physiopathology*; D016022:Case-Control Studies; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013977:Tibia / Q000033:anatomy & histology / Q000473:pathology*; D055815:Young Adult
keywords: MRI; knee; patellar tendon