Patellar Tendon Properties and Lower Limb Function in Rheumatoid Arthritis and Ankylosing Spondylitis versus Healthy Controls: A Cross-Sectional Study

• Published in: TheScientificWorld Vol. 2013; no. 2013; pp. 1 - 8
• Main Authors: Thom, Jeanette M., Matschke, Verena, Jones, Jeremy G., Lemmey, Andrew B., Maddison, Peter J.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2013; John Wiley & Sons, Inc; Hindawi Limited; Wiley
• Subjects: Ankylosing spondylitis; Arthritis; Arthritis, Rheumatoid - physiopathology; Biomechanics; Body composition; Clinical Study; Clinical trials; Comparative analysis; Correlation analysis; Cross-Sectional Studies; Disease; Elastic Modulus; Electromyography; Exercise; Female; Force; Gait; Health aspects; Humans; Knee; Leg - physiopathology; Longitudinal studies; Male; Mechanical properties; Middle Aged; Modulus of elasticity; Motor Activity; Muscle, Skeletal - physiopathology; Muscles; Organ Size; Pain; Patellar Ligament - physiopathology; Patients; Physical fitness; Physiological aspects; Physiology; Properties (attributes); Quadriceps muscle; Questionnaires; Reference Values; Rheumatoid arthritis; Rheumatology; Spondylitis; Spondylitis, Ankylosing - physiopathology; Sports medicine; Stiffness; Strength training; Stress, Mechanical; Tendons; Thickening; Ultrasonic imaging; Ultrasound
• ISSN: 2356-6140; 1537-744X; 1537-744X
• DOI: 10.1155/2013/514743

Objective. Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) lead to inflammation in tendons and peritendinous tissues, but effects on biomechanical tendon function are unknown. This study investigated patellar tendon (PT) properties in stable, established RA and AS patients. Methods. We compared 18 RA patients (13 women, 59.0 ± 2.8 years, mean ± SEM) with 18 age- and sex-matched healthy controls (58.2 ± 3.2 years), and 12 AS patients (4 women, 52.9 ± 3.4 years) with 12 matched controls (54.5 ± 4.7 years). Assessments with electromyography, isokinetic dynamometry, and ultrasound included quadriceps muscle force and cross-sectional area (CSA), PT stiffness, and PT CSA. Additionally, measures of physical function and disease activity were performed. Results. PT stiffness and physical function were lower in RA and AS patients compared to healthy controls, without a significant difference in force production. PT CSA was significantly larger leading to reduction in Young’s modulus (YM) in AS, but not in RA. Conclusion. The adverse changes in PT properties in RA and AS may contribute to their impaired physical function. AS, but not RA, leads to PT thickening without increasing PT stiffness, suggesting that PT thickening in AS is a disorganised repair process. Longitudinal studies need to investigate the time course of these changes and their response to exercise training.