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Reference Values for Patellofemoral Alignment

Osteoarthritis Cartilage; ePub 2017 Jun 22; Macri, et al

Sulcus angle (SA), patellar tilt, and bisect offset were most strongly associated with full thickness cartilage damage, according to a recent study that examined patellofemoral (PF) morphology and alignment as they relate to PF osteoarthritis. Furthermore, lateral trochlear inclination (LTI), patellar tilt, and bisect offset had stronger associations with the addition of pain. Researchers evaluated data from The Framingham Community Cohort, a population-based sample of ambulatory adults aged ≥50 years. They investigated 6 morphology and alignment measures using MRI (n=985), and reported reference values in a subsample without MRI-defined PF full thickness cartilage damage or knee pain (n=563). They found:

  • For dose-response curves, prevalence ratios (PR) increased monotonically for all measures except patellar tilt, which rose with both lateral and medial tilt.
  • Associations were generally strongest in the lateral PF compartment.
  • PR for the strongest predictors of full thickness cartilage damage reached clinical relevance (PR > 1.5) at SA ≥135.0°; patellar tilt angle at ≤1.0° and ≥15.0°; and bisect offset ≥57.0%.

Citation:

Macri EM, Felson DT, Zhang Y, et al. Patellofemoral morphology and alignment: reference values and dose–response patterns for the relation to MRI features of patellofemoral osteoarthritis. [Published online ahead of print June 22, 2017]. Osteoarthritis Cartilage. doi:10.1016/j.joca.2017.06.005.