Developmental dysplasia of the hip (DDH) is an abnormal development or dislocation of the hip joint present from birth.

DDH can be unilateral or bilateral. It affects the left hip more often (67%) than the right. This abnormality occurs in three degrees of severity:

Muscular dystrophy is a group of congenital disorders characterized by progressive symmetric wasting of skeletal muscles without neural or sensory defects. Paradoxically, some wasted muscles tend to enlarge (pseudohypertrophy) because connective tissue and fat replace muscle tissue, giving a false impression of increased muscle mass. The prognosis varies with the form of disease. The four main types of muscular dystrophy include:

Osteomyelitis is a bone infection characterized by progressive inflammatory destruction after the formation of new bone. It commonly results from a combination of local trauma — usually trivial but causing a hematoma — and an acute infection originating elsewhere in the body. Although osteomyelitis usually remains localized, it can spread through the bone to the marrow, cortex, and periosteum.

Osteomyelitis is usually classified as acute if symptoms have been present for less than 2 weeks, subacute between 2 weeks and 3 months, or chronic if greater than 3 months (Chiappini et al., 2016).

Acute osteomyelitis is usually a blood-borne disease and most commonly affects rapidly growing children, with an estimated incidence of 8 cases per 100,000 children/year and a male:female ratio of 2:1. The long bones, such as the femur, are the most frequently involved and the lower extremities are more affected than the upper extremities (Yeo & Ramachandran, 2014). Although rare, with chronic osteomyelitis, drainage of the sinus tracts may be necessary and widespread lesions may be present. Possible consequences may include amputation of an arm or leg when resistant chronic osteomyelitis causes severe, unrelenting pain and decreased function due to weakened bone cortex.

Primary malignant bone tumors (also called sarcomas of the bone and bone cancer) are rare, and while constituting only 1% of new cancer diagnoses, it accounts for 2% of cancer deaths (Zhang et al., 2016). The incidence is approximately 8 cases per million/year (Aggerholm-Pedersen et al., 2014). Most bone tumors are secondary, caused by seeding from a primary site.

Scoliosis is a lateral curvature of the thoracic, lumbar, or thoracolumbar spine. The curve may be convex to the right (more common in thoracic curves) or to the left (more common in lumbar curves). Rotation of the vertebral column around its axis may cause rib cage deformity. Scoliosis may be associated with kyphosis (humpback) and lordosis (swayback).