Background Placement of a total knee prosthesis (TKP) in case of end-stage knee OA in young patients is less successful than in the elderly, with high revision rates of up to 44% later in life. [1,2] However, in severe end-stage knee OA, effective joint saving treatments are scarce. Recently, knee joint distraction (KJD) showed results of clinical improvement and cartilaginous tissue repair in patients with knee OA. [3] However, no comparative data on efficacy is available. A RCT was set out and determined whether there was a clinical relevant difference between KJD and TKP in clinical outcome 1-year after treatment.

Methods 60 patients with severe knee osteoarthritis were included and randomized to KJD (20 patients) or TKP (40 patients). As clinical outcome parameter a WOMAC questionnaire (100 being the best) and a VAS Pain (0 mm being the best) were assessed at baseline (BL) and 12 months. Off all values mean ± SEM is given.

Results 26 patients, who received a TKP, had at least one-year of follow-up and of the patients who received KJD 16 at least one-year of follow-up available at the cut-off date (December 31st 2014). The 26 patients in the TKP group had a mean age at surgery of 54.8±1.2, a mean BMI of 29.6±0.7 kg/m² and a mean Kellgren & Lawrence grade of 2.7±0.1. The 16 patients in the KJD group had a mean age at surgery of 57.1±1.8, a mean BMI of 26.8±1.0 and a mean Kellgren & Lawrence grade of 3.6±0.2. Total WOMAC scores demonstrated significant clinical improvement in both groups (see also figure 1). The KJD group increased from 50±3 points at BL to 80±4 points at 1-year (p<0.001). Similarly, the TKP group had a score of 47±3 points at BL, which increased to 82±3 points (p<0.001). Parallel results were seen for the three subscales of the WOMAC (stiffness, pain and function) and for the VAS. None of the parameters showed a statistical significant difference between the two groups at 1-year (p=0.730 for WOMAC total and p=0.116 for the VAS).

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Conclusions KJD does not lead to a clinical relevant difference in outcome compared with TKP after 1-year. Importantly KJD preserves the knee-joint and therefore represents a promising therapeutic option for young patients with severe knee OA.

References

1. Julin J, Jamsen E, Puolakka T, Konttinen YT, Moilanen T. Younger age increases the risk of early prosthesis failure following primary total knee replacement for osteoarthritis. A follow-up study of 32,019 total knee replacements in the Finnish Arthroplasty Register. Acta orthopaedica. 2010;81(4):413-9.

2. Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clinical orthopaedics and related research. 2009;467(10):2606-12.

3. Wiegant K, van Roermund PM, Intema F, Cotofana S, Eckstein F, Mastbergen SC, et al. Sustained clinical and structural benefit after joint distraction in the treatment of severe knee osteoarthritis. Osteoarthritis and cartilage/OARS, Osteoarthritis Research Society. 2013;21(11):1660-7.

Acknowledgements ZonMw (The Netherlands Organisation for Health Research and Development) and the Dutch Arthritis Association support this study.

Disclosure of Interest None declared