Article Text

Extended report
Tissue structure modification in knee osteoarthritis by use of joint distraction: an open 1-year pilot study
  1. Femke Intema1,
  2. Peter M Van Roermund2,
  3. Anne C A Marijnissen1,
  4. Sebastian Cotofana3,
  5. Felix Eckstein3,
  6. Rene M Castelein2,
  7. Johannes W J Bijlsma1,
  8. Simon C Mastbergen1,
  9. Floris P J G Lafeber1
  1. 1Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
  2. 2Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
  3. 3Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical University, Salzburg, Austria
  1. Correspondence to Prof Floris Lafeber, Rheumatology & Clinical Immunology, UMC Utrecht, F02.127, PO BOX 85500, 3508 GA Utrecht, The Netherlands; f.lafeber{at}


Background Modification of joint tissue damage is challenging in late-stage osteoarthritis (OA). Few options are available for treating end-stage knee OA other than joint replacement.

Objectives To examine whether joint distraction can effectively modify knee joint tissue damage and has the potential to delay prosthesis surgery.

Methods 20 patients (<60 years) with tibiofemoral OA were treated surgically using joint distraction. Distraction (∼5 mm) was applied for 2 months using an external fixation frame. Tissue structure modification at 1 year of follow-up was evaluated radiographically (joint space width (JSW)), by MRI (segmentation of cartilage morphology) and by biochemical markers of collagen type II turnover, with operators blinded to time points. Clinical improvement was evaluated by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Visual Analogue Scale (VAS) pain score.

Results Radiography demonstrated an increase in mean and minimum JSW (2.7 to 3.6 mm and 1.0 to 1.9 mm; p<0.05 and <0.01). MRI revealed an increase in cartilage thickness (2.4 to 3.0 mm; p<0.001) and a decrease of denuded bone areas (22% to 5%; p<0.001). Collagen type II levels showed a trend towards increased synthesis (+103%; p<0.06) and decreased breakdown (−11%; p<0.08). The WOMAC index increased from 45 to 77 points, and VAS pain decreased from 73 to 31 mm (both p<0.001).

Conclusions Joint distraction can induce tissue structure modification in knee OA and could result in clinical benefit. No current treatment is able to induce such changes. Larger, longer and randomised studies on joint distraction are warranted.

This paper is freely available online under the BMJ Journals unlocked scheme, see

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  • Funding This study was financially supported by the Dutch Arthritis Foundation.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the University Medical Center Utrecht.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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