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.
Keywords: Cartilage repair; High tibial osteotomy; Joint distraction; Knee osteoarthritis.