- March 2008 - Volume 31 · Issue 3:
The musculoskeletal system is the complex integrative end-result of evolution that serves a dual function: a) its bony component forms a skeleton that is the scaffold determining body size and shape onto which all other tissues are attached, and b) connections between bones have developed into joints that allow movement and control the magnitude of energy investment needed for each cycle of movement.
When the German physicist Wilhelm Conrad Roentgen discovered and described radiographs in1895, they swiftly became the most widely used imaging modality in science and medicine. The creative imagination of medical research as well as clinical practice become focused first and foremost onto what radiologic imaging could demonstrate. Therefore, when Julius Wolff1 summarized his landmark morphological observations on bone, they become Wolffs Law, which is correct and undisputed to this day. It simply states that bones microarchitecture has a continuous mutual dynamic relationship with the transmission of load through it. The quest to provide a clear scientific definition of who this mutual partner of bone is responsible for the online transmission of load through it; thus the physiologic shield of its microarchitecture has never been clearly discussed in the literature. Available data was abundant, from the published studies of Cooper,2 Friedenstein,3 Lanyon and Rubin,4 Michelson et al,5 Buckwalter and Grodzinsky,6 Sakata et al,7 to Stein et al.8
These studies suggest that bone and its muscle envelope are two different morphologic structures of which function is one integrated physiological and functional unit. While bone provides the construction scaffold that ensures the muscles resting length, the muscle envelope provides the ability to create movement, transmit loads, and contribute to new bone formation.9-12
Recognizing this fact, that bone and its muscle envelope form a single, closely knit functional unit that provides the scientific basis to decode and understand Wolffs law. This might further enhance our understanding of a variety of clinical conditions first and foremost among them being osteoporosis.
- Wolff J. Das Gesetz der Transformation der Knochen. Berlin, Germany; Verlag von August Hirschwald:1892.
- Cooper RR. Alterations during immobilization and regeneration of skeletal muscle in cats. J Bone Joint Surg Am. 1972; 54(5):919-950.
- Friedenstein AJ. Induction of bone tissue by transitional epithelium. Clin Orthop Relat Res. 1968;59:21-37.
- Lanyon LE, Rubin CT. Static vs dynamic loads as an influence on bone remodeling. J Biomech. 1984;17(12):897-905.
- Michelsson JE, Pettila M, Valtakari T, Leivo J, Aho HJ. Isolation of bone from muscles prevents the development of experimental callus-like heterotopic bone. A study of the interaction of bone and muscle in new bone formation. Clin Orthop Relat Res. 1994; (302):266-272.
- Buckwalter JA, Grodzinsky AJ. Loading of healing bone, fibrous tissue and muscle: implications for orthopaedic practice. J Am Acad Orthop Surg. 1999; 7(5):291-299.
- Sakata T, Halloran BP, Elalieh HZ, et al. Skeletal unloading induces resistance to insulin-like growth factor I on bone formation. Bone. 2003; 32(6):669-680.
- Stein H, Perren SM, Cordey J, Kenwright J, Mosheiff R, Francis MJ. The muscle bed-a crucial factor for fracture healing: a physiological concept. Orthopedics. 2002; 25(12):1379-1383.
- Ilizarov GA. The tension-stress effect on the genesis and growth of tissues, I: the influence of stability of fixation and soft-tissue preservation. Clin Orthop Relat Res. 1989; (238):249-281.
- Levy MM, Joyner CJ, Virdi AS, et al. Osteoprogenitor cells of mature human skeletal muscle tissue: an in-vitro study. Bone. 2001; 29(4):317-322.
- Young BH, Peng H, Huard J. Muscle-based gene therapy and tissue engineering to improve bone healing. Clin Orthop Relat Res. 2002; 403(suppl):s243-s251.
- Stein H, Rozen N, Kaufman H, Lerner A. Adult (somatic) stem cells and the musculoskeletal system. Orthopedics. 2006; 29(5):418-421.
Drs Stein is from Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel, and Dr DAmbrosia is Editor-in-Chief of Orthopedics.