Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Clinical Improvement and Structural Tissue Repair by Joint Distraction, in Treatment of End-Stage Knee Osteoarthritis.

Intema2,  F., Wiegant3,  K., van Roermund3,  P. M., Marijnissen3,  A. C. A., Cotofana1,  S., Eckstein1,  F., Mastbergen3,  S. C.

Institute of Anatomy and Muscoskeletal Research, Paracelsus Medical University, Salzburg, Austria
Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
Rheumatology & Clinical Immunology, University Medical Center Utrecht, The Netherlands

Background:

End-stage knee osteoarthritis (OA) is frequently treated by total knee replacement (TKP). In 40% of the cases this expensive treatment is performed under the age of 65 years, while the procedure has a higher risk of failure in younger patients, due to higher physical demands.

Knee joint distraction (KJD) is an experimental treatment for end-stage knee OA, aimed at unloading the joint cartilage and subchondral bone by use of a 'fixateur externe'. The technique proved to be clinically effective for end-stage ankle OA. The present study describes an exploratory, open, uncontrolled trial to verify whether KJD has the potency to postpone a TKP by inducing clinical improvement and cartilage repair.

Methods:

Twenty patients, under 60 years of age, with end-stage knee OA were treated with KJD for 2 months. Two monotubes with internal coil springs were placed parallel (medial and lateral) bridging the knee joint and were distracted for 5 mm. Patients were encouraged to load the knee during distraction, in order to achieve intermittent intra-articular fluid pressures. During the treatment most patients (n=17) suffered from single or multiple pin tract infections, all being successfully treated with antibiotics.

After 2 months, tubes and pins were removed, and function was actively practiced.

The primary clinical outcome was pain and function by use of the WOMAC questionnaire. For secondary clinical outcome VAS pain was documented. Primary structural outcome was cartilage thickness by use of quantitative MRI and digital analyses of standardized X-rays. Secondary outcome parameters were MRI determined decrease in area of denuded bone, increase in cartilage area and volume as well as biochemical markers of cartilage. All structural parameters were analyzed blinded.

Results:

One year after distraction, the total WOMAC score improved significantly from 45% at baseline to 77% (p<0.001). This improvement is supported by a decrease in VAS pain score from 73 to 31 mm (p<0.001).

Complementary, quantitative MRI analysis showed an increase in cartilage thickness of the affected compartment from 2.4 to 3.0 mm (p<0.01), both femur and tibia. The total area of denuded bone decreased from 22% to 5% (p<0.01). Cartilage area and volume increased from 15.6 to 18.9 cm2 and 2.3 to 2.8 cm3 (both p<0.05).

X-ray analysis corroborated the MRI findings by an increased mean, as well as minimum JSW from 2.7 to 3.6 mm (p<0.05) and 1.0 to 1.9 mm (p<0.01), respectively.

Increase in cartilage area and thickness and decrease in denuded bone area correlated with the increase in the mean radiographical JSW (r=0.571, r=0.553, r=-0.613 resp. all p<0.05)

Long term changes in biomarkers showed a decrease of collagen type II breakdown marker CTXII (-11%; p=0.04) and an increase of collagen type II synthesis marker PIIANP (+103%; p=0.03). The average change in the ration of PIIANP/CTXII of each patient was in favor of synthesis (p<0.03).

Conclusion:

In treatment of end-stage knee OA it is proven to induce significant intrinsic joint cartilage repair by use of joint distraction, based on MRI, X-ray and biochemical marker analyses. These significant tissue structure changes are accompanied by clinical improvement in pain and function.

To cite this abstract, please use the following information:
Intema, F., Wiegant, K., van Roermund, P. M., Marijnissen, A. C. A., Cotofana, S., Eckstein, F., et al; Clinical Improvement and Structural Tissue Repair by Joint Distraction, in Treatment of End-Stage Knee Osteoarthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1380
DOI: 10.1002/art.29146

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