EFFICACY AND COMPLIANCE OF A QUADRICEPS FEMORIS NEUROMUSCULAR ELECTRICAL STIMULATION PROGRAM IN SUBJECTS WITH SEVERE KNEE OSTEOARTHRITIS

Abstract

Quadriceps femoris muscle (QFM) weakness is associated with the development of knee osteoarthritis (OA). Neuromusclar electrical stimulation (NMES) circumvents neural inhibition causing muscle contraction, however there is little reported data demonstrating its role in knee OA. Our aim was to evaluate the effectiveness of a NMES program in patients with knee OA.

Sixteen patients (10 women, 6 men) with severe knee OA were randomised into control (n=6) or intervention (n=10) groups. These were similar in terms of age (64.8 ± 11.0 vs. 64.6 ± 7.6; mean ± SD) and BMI (31.8 ± 6.11 vs.30.7 ± 2.9). NMES was applied using a garment-based stimulator for 20 min/day, 5 d/wk for 8 weeks. Isokinetic and isometric QFM strength were determined at baseline, and weeks 2, 5, and 8 using a dynomometer. Functional assessments involved a 25 metre timed walk test (TWT), timed stair-climb test (SCT), and timed chair-rise test (CRT) at baseline and week 8. Subjects recorded NMES session duration in a log book while the device also recorded total treatment time.

Function significantly improved in the NMES group as determined by the timed SCT (p< 0.01) and the timed CRT (p< 0.01) at week 8 compared to week 0. Isometric QFM strength was significantly higher in the NMES group at weeks 2, 5 and 8 than week 0. Compared to week 0, isokinetic hamstring strength increased significantly in the NMES group at week 2, week 5 and week 8 while isokinetic QFM strength increased at week 5 (p< 0.05) and week 8 (p< 0.01). Patient recorded compliance was 99.5% (range, 97.1%–100%) and overall usage recorded on the stimulator was 96.1% ± 13.2.

The use of a portable home-based NMES program produced significant QFM strength gain with associated improvement in function in patients with severe knee OA. Compliance was excellent overall.