title: Sustained clinical and structural benefit after joint distraction in the treatment of severe knee osteoarthritis.
abstract: BACKGROUND
  Treatment of severe osteoarthritis (OA) in relatively young patients is challenging. Although successful, total knee prosthesis has a limited lifespan, with the risk of revision surgery, especially in active young patients. Knee joint distraction (KJD) provides clinical benefit and tissue structure modification at 1-year follow-up. The present study evaluates whether this benefit is preserved during the second year of follow-up.
  
  
  METHODS
  Patients included in this study presented with end-stage knee OA and an indication for total knee replacement (TKR); they were less than 60 years old with a VAS pain ≥60 mm (n = 20). KJD was applied for 2 months (range 54-64 days) and clinical parameters assessed using the WOMAC questionnaire and VAS pain score. Changes in cartilage structure were measured using quantitative MRI, radiography, and biochemical analyses of collagen type II turnover (ELISA).
  
  
  RESULTS
  Average follow-up was 24 (range 23-25) months. Clinical improvement compared with baseline (BL) was observed at 2-year follow-up: WOMAC improved by 74% (P < 0.001) and VAS pain decreased by 61% (P < 0.001). Cartilage thickness observed by MRI (2.35 mm (95%CI, 2.06-2.65) at BL) was significantly greater at 2-year follow-up (2.78 mm (2.50-3.09); P = 0.03). Radiographic minimum joint space width (JSW) (1.1 mm (0.5-1.7) at BL) was significantly increased at 2-year follow-up as well (1.7 mm (1.1-2.3); P = 0.03). The denuded area of subchondral bone visualized by MRI (22% (95%CI, 12.5-31.5) at BL) was significantly decreased at 2-year follow-up (8% (3.6-12.2); P = 0.004). The ratio of collagen type II synthesis over breakdown was increased at 2-year follow-up (P = 0.07).
  
  
  CONCLUSIONS
  Clinical improvement by KJD treatment is sustained for at least 2 years. Cartilage repair is still present after 2 years (MRI) and the newly formed tissue continues to be mechanically resilient as shown by an increased JSW under weight-bearing conditions.
authors: Rheumatology & Clinical Immunology, UMCU, Netherlands; Orthopedics, UMCU, Netherlands.
authors: K
authors: K
authors: Wiegant
authors: P M
authors: PM
authors: van Roermund
authors: F
authors: F
authors: Intema
authors: S
authors: S
authors: Cotofana
authors: F
authors: F
authors: Eckstein
authors: S C
authors: SC
authors: Mastbergen
authors: F P J G
authors: FP
authors: Lafeber
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology; D024043:Collagen Type II / Q000378:metabolism; D016267:External Fixators; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D019857:Osteogenesis, Distraction / Q000009:adverse effects / Q000379:methods*; D011859:Radiography; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D024043:Collagen Type II
keywords: Cartilage repair; Joint distraction; Knee; MRI; Osteoarthritis; Treatment