Compensatory Strategies for Muscle Weakness During Stair Ascent in Subjects With Total Knee Arthroplasty

• Published in: The Journal of arthroplasty Vol. 29; no. 7; pp. 1499 - 1502
• Main Authors: Bjerke, Joakim, Öhberg, Fredrik, Nilsson, Kjell G., Stensdotter, Ann K.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2014
• Subjects: Aged; Arthroplasty, Replacement, Knee - methods; Biomechanical Phenomena; Cross-Sectional Studies; Electromyography; Female; Gait - physiology; Humans; kinematics; Knee Joint - physiology; Knee Joint - surgery; Leg - surgery; Male; maximal voluntary contraction; Middle Aged; Muscle Weakness - surgery; Muscle, Skeletal - physiology; Muscle, Skeletal - surgery; muscular utilization; muscular utilization. electromyography. maximal voluntary contraction. kinematics. stairs; Orthopedics; Quadriceps Muscle - surgery; stairs; Walking; muscular utilization; maximal voluntary contraction; kinematics; electromyography; stairs
• ISSN: 0883-5403; 1532-8406; 1532-8406
• DOI: 10.1016/j.arth.2014.01.033

Subjects with total knee arthroplasty (TKA) exhibit decreased quadriceps and hamstring strength. This may bring about greater relative effort or compensatory strategies to reduce knee joint moments in daily activities. To study gait and map out the resource capacity, knee muscle strength was assessed by maximal voluntary concentric contractions, and whole body kinematics and root mean square (RMS) electromyography (EMG) of vastus lateralis and semitendinosus were recorded during stair ascent in 23 unilateral TKA-subjects ~19months post-operation, and in 23 healthy controls. Muscle strength and gait velocity were lower in the TKA group, but no significant group differences were found in RMS EMG or forward trunk lean. The results suggest that reduced walking velocity sufficiently compensated for reduced knee muscle strength.