Effect of knee aspiration and intra-articular corticosteroid injection on gait biomechanics and strength in patients with knee osteoarthritis.

Objective: To evaluate the effect of knee aspiration and intraarticular corticosteroid injection on gait biomechanics and strength in patients with knee osteoarthritis (OA) and active inflammation. Methods: Fifteen patients with knee OA, synovitis and effusion were tested before and 3 weeks after receiving a knee aspiration and triamcinolone injection. All patients' ultrasound (US) exam revealed signs of inflammation that aligned with symptoms. A standard of care knee aspiration and injection was performed under US guidance. Three-dimensional quantitative gait analysis included peak knee angles and moments during walking. Muscular strength testing included isokinetic knee flexion and extension torque at 90 deg/s. Ultrasound, gait and strength tests were completed by the same examiner to reduce variability. Paired t-tests were used to assess changes. Results: Pre minus post mean changes (95% CI) were: peak knee varus angle -0.11 deg (-1.97, 1.76), first peak knee adduction moment (KAM) 0.01 %BW*ht (-0.33, 0.35), second peak KAM -0.05 %BW*ht (-0.49, 0.39), peak knee flexion excursion angle -2.5 deg (-4.50, -0.59), peak knee flexion moment -0.57 %BW*ht (-1.06, -0.68), peak knee extension moment -0.06 %BW*ht (-0.64, 0.52), peak quadriceps strength -6.14 Nm (-16.92, 4.65) and peak hamstring strength -5.59 Nm (-11.14, -0.03). Conclusion: Preliminary results suggest patients undergoing aspiration and injection for knee synovitis and effusion experience increased sagittal plane angles and moments during walking and increased maximal hamstring strength. Clinical implications: Future work will categorize patients as responders and non-responders based on OARSI-OMERACT responder criteria to analyze between group differences. [ABSTRACT FROM AUTHOR]