Chapter 48: Disorders of Musculoskeletal Function – Trauma & Infection

Musculoskeletal trauma covers a broad spectrum of injuries, including common soft-tissue damage like contusions, hematomas, and lacerations, as well as joint injuries such as strains (muscle stretching), sprains (ligament damage due to abnormal movement), dislocations (complete loss of articulation), and the presence of loose bodies. Specific high-risk areas discussed include injuries to the shoulder (rotator cuff and glenohumeral dislocations), the knee (meniscus tears, patellar instability, and chondromalacia), and the hip (dislocations and fractures, particularly prevalent in older adults). Fractures, defined as a discontinuity of the bone, are classified by cause (sudden injury, stress, or pathologic weakening) and type (e.g., open, closed, comminuted, greenstick). Bone repair is a complex, time-dependent four-stage process: hematoma formation, the inflammatory phase, the reparative phase where cartilage and woven bone form a callus, and final remodeling to reconstruct the cortex. Complications can be immediate, such as fracture blisters, Complex Regional Pain Syndrome (CRPS), and the potentially fatal Compartment Syndrome (characterized by severe pain disproportionate to the injury), or delayed, including malunion, delayed union, or nonunion. The discussion transitions to bone infections, primarily osteomyelitis—an acute or chronic infection of the bone and marrow, most commonly caused by Staphylococcus aureus. This infection can spread hematogenously (via bloodstream) or by direct penetration (from open wounds or surgery); chronic osteomyelitis is characterized by the presence of infected dead bone (sequestrum) encased in new bone (involucrum). Osteonecrosis, or bone death, results from interrupted blood supply in the absence of infection, frequently affecting the femoral head due to trauma or prolonged corticosteroid use. Finally, the chapter contrasts benign bone neoplasms (like osteochondroma, often slow-growing) with malignant bone tumors. Primary malignancies, which are rare and fast-growing (e.g., Osteosarcoma and Ewing Sarcoma in younger populations, Chondrosarcoma in adults), are distinguished from the far more common metastatic bone disease, often originating from cancers of the prostate, breast, or lung.