Musculoskeletal or mechanical pain occurs at or above the level of the lesion and is due to changes in bone, tendons or joints (Guttmann 1973). This is referred to as nociceptive pain caused by a variety of noxious stimuli to normally innervated parts of the body (Ragnarsson 1997). Overuse of remaining functional muscles after spinal cord injury or those recruited for unaccustomed activity may be of primary importance in some patients (Farkash & Portenoy 1986). Pain may also be secondary to spinal osteoporosis or facet arthropathy (Farkash & Portenoy 1986). Instability of the vertebral column may also be a problem (Farkash & Portenoy 1986). Pain is usually dull and aching in character and although more common soon after SCI, it may become chronic.
Sie et al. (1992) studied 239 SCI outpatients for the presence of upper extremity pain. Of the 136 patients with quadriplegia, 55% reported upper extremity pain, most commonly at the shoulder (46% of all subjects). In the case of shoulder pain, 45% were orthopedic-related including tendonitis, bursitis, capsulitis and osteoarthritis. Of the 103 paraplegics, 66 reported upper extremity pain with two-thirds reporting symptoms of carpal tunnel syndrome and 13 reporting musculoskeletal-related shoulder pain. Dalyan et al. (1999), in a questionnaire returned by 130 SCI patients, found that 58.5% of patients reported upper extremity pain. Of these, 71% had shoulder pain, 53% wrist pain, 43% hand pain, and 35% elbow pain. Pain was most likely to be associated with pressure relief, transfers, and wheelchair mobility. Subbarao et al. (1995), in a survey of 800 SCI patients, found that 72.7% of responders reported some degree of chronic pain at the wrist and shoulder, with wheelchair propulsion and transfers being responsible for most of the pain. McCasland et al. (2006) noted that in their survey, 70% of SCI had shoulder pain, one-third had a previous injury to their shoulder and 52% reported a bilateral pain. Quadriplegics were more likely to have shoulder pain (80%). Previous shoulder trauma increased the risk of having shoulder pain.