title: Is the severity of knee osteoarthritis on magnetic resonance imaging associated with outcome of exercise therapy?
abstract: OBJECTIVE
  To evaluate associations between severity of knee osteoarthritis (OA) on magnetic resonance imaging (MRI) and treatment outcomes in knee OA patients treated with exercise therapy in an exploratory study.
  
  
  METHODS
  Ninety-five participants with knee OA in a 12-week exercise program had obtained 3.0T MRI scans of the knee joint prior to treatment. MRI data were systematically assessed for OA severity of multiple features (cartilage integrity, bone marrow lesions, osteophyte formation, effusion/synovitis, and meniscal abnormalities) according to the Boston Leeds Osteoarthritis Knee Score method. Regression analyses were performed to analyze associations between OA severity on MRI (for the tibiofemoral and patellofemoral [PF] compartments) and outcome of exercise therapy, i.e., changes in activity limitations (Western Ontario and McMaster Universities Osteoarthritis Index physical function; primary outcome), pain and upper leg muscle strength, and treatment response (Outcome Measures in Rheumatology/Osteoarthritis Research Society International criteria).
  
  
  RESULTS
  Improvements of 24%, 34%, and 21% on average in activity limitations, pain, and muscle strength, respectively, after 12-week exercise therapy were found (P < 0.001). Severity of abnormalities in PF cartilage integrity was significantly associated with fewer improvements in both activity limitations (P = 0.01) and muscle strength (P = 0.04). Severity of PF osteophyte formation was significantly associated with fewer improvements in muscle strength (P < 0.01). All other features on MRI were not associated with treatment outcome.
  
  
  CONCLUSIONS
  Effectiveness of exercise therapy seems to be independent of OA severity on MRI, except for abnormalities in cartilage integrity and osteophyte formation, both in the PF compartment. Our study suggests that all grades of OA severity on MRI can benefit from professionally supervised exercise therapy, although the effects might be reduced in patients with advanced PF OA.
authors: Amsterdam Rehabilitation Research Center|Reade, Amsterdam, The Netherlands.
authors: J
authors: J
authors: Knoop
authors: J
authors: J
authors: Dekker
authors: M
authors: M
authors: van der Leeden
authors: M
authors: M
authors: van der Esch
authors: J P
authors: JP
authors: Klein
authors: D J
authors: DJ
authors: Hunter
authors: L D
authors: LD
authors: Roorda
authors: M P M
authors: MP
authors: Steultjens
authors: W F
authors: WF
authors: Lems
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D018771:Arthralgia / Q000453:epidemiology; D005081:Exercise Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy*; D017063:Outcome Assessment, Health Care; D012044:Regression Analysis; D012720:Severity of Illness Index; D016037:Single-Blind Method; D016896:Treatment Outcome