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BackgroundPlacement of a total knee arthroplasty (TKA) in case of end-stage knee osteoarthritis (OA) in young patients is less successful than in elderly, with high revisions rates later in life (1). Recently knee joint distraction (KJD) showed results of clinical improvement and tissue structure modification in patients with knee OA (2) postponing a TKA. The duration of these beneficial effects is yet unclear.ObjectivesWe evaluated whether the clinical improvement and tissue structure modification in knee OA sustain and persist on MRI and X-rays 5 years after distraction.MethodsPatients (n=20; <60yrs) with tibio-femoral OA who were resistant to conservative therapy and eligible for TKA, were treated with 8 weeks of KJD by use of an external fixator. Clinical evaluation was performed by WOMAC, VAS pain and survival of the knee joint. Changes in cartilage thickness were quantified by MRI, and change in joint space width (JSW) was evaluated on standardized semi-flexed X-rays. The five-year changes after KJD were evaluated and were compared with the natural progression rate of OA in OsteoArthritis-Initiative participants with similar baseline characteristics.ResultsFrom 20 patients (age 49±6 yrs), two withdrew informed consent and three other patients were treated with TKP (after three and four years), so the survival of the knee joint was 80% at 5 years. Moreover, there was persistent clinical improvement compared to baseline sustaining over time: Δ WOMAC +21,1 points (CI:8,9-33,3; p=0.002), Δ VAS pain -27,6mm (CI:-13,3-42,0; p<0.001).In addition, minimum radiographic JSW was increased at five years as compared to pre-treatment values: Δ+0,43mm (CI:0,02-0,84; p=0.040). Taking natural loss of cartilage thickness into account, this change was significantly different from the changes as a result of extrapolated natural progression (Δ-0,39mm and Δ-0,18mm, respectively) resulting at 5 years in a difference of +0,65mm (CI:0,07-1,23; p=0.031) and of +0,41mm (CI:0,07-0,74; p=0.020) for mean JSW on X-ray and average cartilage thickness on MRI, respectively.ConclusionsIn young OA patients, TKA can be postponed for at least five years in 80% of the patients. KJD treatment results in persistent clinical benefit and an increase in cartilage thickness and JSW.The effects were not as strong as observed 1 and 2 years after treatment, still they represented a significant structural benefit compared to the natural course of the disease. Joint distraction has great potential to effectively postpone TKA and as such represents a promising therapeutic option for young patients with severe knee OA.ReferencesJulin J, Jamsen E, Puolakka T,et al. 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.Wiegant K, van Roermund PM, et al. Sustained clinical and structural benefit after joint distraction in the treatment of severe knee osteoarthritis. Osteoar...

according to the ACR criteria. ** Knee OA, defined as K&L grade ! 2. *** GEE adjusted for baseline differences and confounding factors (baseline BMI, baseline K&L grade, baseline mild knee symptoms, history of knee injury).

BackgroundPlacement 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.Methods60 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.Results26 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).ConclusionsKJD 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.ReferencesJulin 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.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.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.AcknowledgementsZonMw (Th...

BackgroundIn osteoarthritis knee joint distraction (KJD) provides clinical benefit and tissue structure modification at 1 year and beyond. During the previous regime of an 8-week distraction period patients visited every 2 weeks day care practice for temporarily removal of the distraction frame. 8 weeks of intermittent KJD with frequent hospital visits is perceived as a considerable burden. This study evaluates whether 6 weeks of continuous KJD gives similar tissue structure repair and clinical benefit compared to eight weeks of KJD at 1-year follow-up.MethodsBoth groups consisted of 20 patients with knee OA and were treated with 5 mm joint distraction by use of an external fixator for 8 weeks with every 2 weeks CPM or 6 weeks continuously. WOMAC questionnaires were assessed, representing the clinical outcome. Structural outcome was quantified as mean joint space width (JSW) on standardized semi-flexed x-rays at baseline and one-year of follow-up using KIDA. T-tests were applied to analyze change over time.ResultsClinical improvement compared to baseline (BL) was observed in both groups. The 6-week group showed a comparable increase from 53±17 points at BL to 76±17 points at one-year follow up (p<0.001) as the 8-week group (from 45±16 points at BL to 77±21 points at the 1-year follow-up; p<0.001). The structural parameters revealed parallel improvements between both groups. The mean JSW of the most affected compartment of the six-week group increased from 1.80±1.61mm to 2.86±1.59mm at 1 year (p=0.001) vs. 2.63±1.62mm to 3.55±0.99mm at 1 year (p=0.006) for the 8-week group. No significant statistical difference between the two groups (p=0.729) was observed.ConclusionsSix weeks of continuous KJD gives significant clinical and structural improvement. Moreover, 6-weeks of continuous distraction treatment does not lead to a stiffer knee in comparison with the “intermittent” 8-week treatment.AcknowledgementsZonMw (The Netherlands Organisation for Health Research and Development) and the Dutch Arthritis Association support this study.Disclosure of InterestNone declared