Tactile acuity and left/right judgment performance in patients with knee osteoarthritis: A cross-sectional study

Abstract

BackgroundLeft/right judgment task (LRJT) performance and tactile acuity are impaired in chronic pain conditions, however, evidence is limited for knee osteoarthritis (OA). ObjectiveTo compare LRJT performance and the two-point discrimination threshold (TPDT) of chronic knee OA patients with asymptomatic knee and pain-free controls. DesignCross-sectional study. MethodsFifty knee OA patients and 50 age and gender-matched pain-free controls were assessed using the Recognize® application by displaying knee images and a digital caliper for the TPDT of the medial and lateral knee joint line. ResultsTPDTs over the lateral joint line in symptomatic (mean difference [MD]: 13.59 mm; 95% confidence interval [CI]: 8.72, 18.46; d = 1.40) and asymptomatic knee (MD: 10.15 mm; 95% CI: 5.08, 15.22; d = 0.99) were significantly increased compared to pain-free controls. Similarly, TPDTs of the medial joint line were significantly increased in symptomatic (MD: 12.19 mm; 95% CI: 7.59, 16.79; d = 1.31) and asymptomatic knee (MD: 7.64 mm; 95% CI: 3.64, 11.64; d = 1.31) compared to pain-free controls. Patients with knee OA were less accurate (MD: 7.80%; 95% CI: 15.32, −0.27; d = 0.52) recognizing images of their symptomatic knee. No correlation was found between pain severity, pain duration, LRJT performance, and TPDTs. Post-hoc analysis revealed no differences in LRJT and TPDTs between patients with and without clinically relevant symptoms of central sensitization. ConclusionChronic knee OA is associated with increased TPDT for medial and lateral knee joint lines and decreased recognition accuracy performance which should be considered during treatment process.