Knee joint distraction compared with total knee arthroplasty: a randomised controlled trial.

AIMS: Knee joint distraction (KJD) is a relatively new, knee-joint preserving procedure with the goal of delaying total knee arthroplasty (TKA) in young and middle-aged patients. We present a randomised controlled trial comparing the two. PATIENTS AND METHODS: The 60 patients ≤ 65 years with end-stage knee osteoarthritis were randomised to either KJD (n = 20) or TKA (n = 40). Outcomes were assessed at baseline, three, six, nine, and 12 months. In the KJD group, the joint space width (JSW) was radiologically assessed, representing a surrogate marker of cartilage thickness. RESULTS: In total 56 patients completed their allocated treatment (TKA = 36, KJD = 20). All patient reported outcome measures improved significantly over one year (p < 0.02) in both groups. At one year, the TKA group showed a greater improvement in only one of the 16 patient-related outcome measures assessed (p = 0.034). Outcome Measures in Rheumatology-Osteoarthritis Research Society International clinical response was 83% after TKA and 80% after KJD. A total of 12 patients (60%) in the KJD group sustained pin track infections. In the KJD group both mean minimum (0.9 mm, standard deviation (sd) 1.1) and mean JSW (1.2 mm, sd 1.1) increased significantly (p = 0.004 and p = 0.0003). CONCLUSION: In relatively young patients with end-stage knee osteoarthritis, KJD did not demonstrate inferiority of outcomes at one year when compared with TKA. However, there is a high incidence of pin track infection associated with KJD. Cite this article: Bone Joint J 2017;99-B:51-8.

Knee joint distraction compared with high tibial osteotomy: a randomized controlled trial.

PURPOSE: Both, knee joint distraction as a relatively new approach and valgus-producing opening-wedge high tibial osteotomy (HTO), are knee-preserving treatments for knee osteoarthritis (OA). The efficacy of knee joint distraction compared to HTO has not been reported. METHODS: Sixty-nine patients with medial knee joint OA with a varus axis deviation of <10° were randomized to either knee joint distraction (n = 23) or HTO (n = 46). Questionnaires were assessed at baseline and 3, 6, and 12 months. Joint space width (JSW) as a surrogate measure for cartilage thickness was determined on standardized semi-flexed radiographs at baseline and 1-year follow-up. RESULTS: All patient-reported outcome measures (PROMS) improved significantly over 1 year (at 1 year p < 0.02) in both groups. At 1 year, the HTO group showed slightly greater improvement in 4 of the 16 PROMS (p < 0.05). The minimum medial compartment JSW increased 0.8 ± 1.0 mm in the knee joint distraction group (p = 0.001) and 0.4 ± 0.5 mm in the HTO group (p < 0.001), with minimum JSW improvement in favour of knee joint distraction (p = 0.05). The lateral compartment showed a small increase in the knee joint distraction group and a small decrease in the HTO group, leading to a significant increase in mean JSW for knee joint distraction only (p < 0.02). CONCLUSION: Cartilaginous repair activity, as indicated by JSW, and clinical outcome improvement occurred with both, knee joint distraction and HTO. These findings suggest that knee joint distraction may be an alternative therapy for medial compartmental OA with a limited mechanical leg malalignment. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

Early evolving joint degeneration by cartilage trauma is primarily mechanically controlled.

BACKGROUND: Mechanical and inflammatory processes add to osteoarthritis (OA). To what extent both processes contribute during the onset of OA after a cartilage trauma is unknown. This study evaluates whether local cartilage damage leads to focally confined or more generalized cartilage damage with synovial inflammation in the early development of joint tissue degeneration. METHODS: In nine goats, cartilage damage was surgically induced on the weight bearing area of exclusively the medial femoral condyle of the right knee joint. The other tibio-femoral compartments, lateral femoral condyle and lateral medial tibial plateau, were left untouched. The contralateral left knee joint of each animal served as an intra-animal control. Twenty weeks post-surgery changes in cartilage matrix integrity in each of the four compartments, medial and lateral synovial tissue inflammation, and synovial fluid IL-1ß and TNFα were evaluated. RESULTS: In the experimental medial femoral plateau, significant macroscopic, histologic, and biochemical cartilage damage was observed versus the contralateral control compartments. Also the articulating cartilage of the experimental medial tibial plateau was significantly more damaged. Whereas, no differences were seen between the lateral compartments of experimental and contralateral control joints. Synovial tissue inflammation was mild and only macroscopically (not histologically) significantly increased in the experimental medial compartments. Synovial fluid IL-1ß level was not different between experimental and contralateral control joints, and TNFα was overall beneath the detection limit. CONCLUSIONS: Local cartilage damage is a trigger for development of OA, which in early onset seems primarily mechanically driven. Early treatment of traumatic cartilage damage should take this mechanical component into consideration.

Sustained clinical and structural benefit after joint distraction in the treatment of severe knee osteoarthritis.

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). CONCLUSION: 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.