In all cases of musculoskeletal pain and lameness, diagnostic procedures to determine the nature, extent, and exact location of the injury must be performed. Evaluation of the source of pain and lameness always starts with a thorough history, inspection, and physical examination to look for sources of heat, swelling, and pain on manual palpation. In horses, hoof testers should be applied to determine whether pain can be elicited from structures within the hoof capsule. Next, the gait and locomotion of the animal are evaluated. In a weight-bearing lameness, the lame leg always bears less weight and often has a shorter duration of bearing weight. In swinging leg lameness, the lame leg abducts or adducts to avoid flexion of a painful joint. These findings can be measured objectively using a force plate or a computerized gait analysis system. In horses, flexion tests of joints followed immediately by gait evaluation at a trot may help localize pain.
After determining which limb is lame, diagnostic analgesia (intra-articular or perineural) can be used to localize the painful gait to a specific anatomic structure or a region of the affected limb. After localization, diagnostic imaging techniques can be performed to evaluate the soft-tissue structures and bones. These diagnostic imaging procedures include radiography, ultrasonography, MRI, CT, nuclear imaging, and thermography. When joint sepsis is suspected, synovial fluid analysis of affected joints is necessary for diagnosis. After these procedures, a diagnosis can be made, treatment instituted, and a prognosis given based on the diagnosis, extent of disease, and expected response to therapy.
Therapeutic options for diseases of the musculoskeletal system include rest, restricted or modified activity, immobilization of diseased or injured structures in splints and casts, NSAIDs, corticosteroid administration, physical therapy, acupuncture, extracorporeal shock wave therapy, and surgical repair. Therapeutic options for management of musculoskeletal disorders have greatly expanded recently with the use of regenerative medicine, in which growth factors and mesenchymal cell therapy have been used to augment healing. A return to a useful life for many animals is possible when diagnosis and subsequent treatment is done early in the disease process.