In vivo measurement of shoulder joint loads during activities of daily living

• Published in: Journal of biomechanics Vol. 42; no. 12; pp. 1840 - 1849
• Main Authors: Westerhoff, P, Graichen, F, Bender, A, Halder, A, Beier, A, Rohlmann, A, Bergmann, G
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 25-08-2009; Elsevier Limited
• Subjects: Activities of Daily Living; Aged; Aged, 80 and over; Biomechanical Phenomena; Female; Humans; In vivo; Joint Prosthesis; Lifting; Load measurement; Male; Middle Aged; Osteoarthritis - physiopathology; Patients; Physical Medicine and Rehabilitation; Shoulder joint; Shoulder Joint - physiology; Telemetry; Transplants & implants; In vivo; Shoulder joint; Load measurement; Telemetry
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2009.05.035

Abstract Until recently the contact loads acting in the glenohumeral joint have been calculated using musculoskeletal models or measured in vitro . Now, contact forces and moments are measured in vivo using telemeterized shoulder implants. Mean total contact forces from four patients during eight activities of daily living are reported here. Lifting a coffee pot (1.5 kg) with straight arm caused an average force of 105.0%BW (%body weight) (range: 90–124.6%BW), while setting down the coffee pot in the same position led to higher forces of 122.9%BW on the average (105.3–153.4%BW). The highest joint contact forces were measured when the straight arm was abducted or elevated by 90° or more, with a weight in the hand. Lifting up 2 kg from a board up to head height caused a contact force of 98.3%BW (93–103.6%BW); again, setting it down on the board led to higher forces of 131.5%BW (118.8–144.1%BW). In contrast to previously calculated high loads, the contact force during passive holding of a 10 kg weight laterally was only 12.3%BW (9.2–17.9%BW), but when lifting it up to belt height it increased to 91.5%BW (87–95%BW). The moments transferred inside the joint at our patients varied much more than did the forces both inter and intra-individually. Our data suggest that patients with shoulder problems or during the first post-operative weeks after shoulder fractures or joint replacements should avoid certain activities encountered during daily living e.g. lifting or holding a weight with an outstretched arm. Some energy-related optimization criteria used in the literature for analytical musculoskeletal shoulder models must now be reconsidered.