Altered gait may have many causes. The following is a list arranged by etiological categories; you may add more as your read around this module and research this topic. The most important diagnoses to be aware of are bolded. These will be discussed more fully in this module and in the Bone and Joint Pain module.
Congenital causes: Developmental Hip Dysplasia
Infectious: Septic hip (bacterial)
Inflammatory: Transient synovitis (probably viral or post-viral), Juvenile Rheumatoid Arthritis
Neoplastic: Primary bone tumour, hematogenous malignancy (leukemia, lymphoma)
Neurological: Cerebral Palsy
Endocrine: Rickets
Traumatic: Slipped Capital Femoral Epiphysis, Fracture, Sprain, Intra-articular derangement
Vascular: Legg-Calve-Perthes Disease (Avascular necrosis of the femoral head)
Developmental: Rotational malalignment
When evaluating a child presenting with altered gait, it is important to differentiate acute illness that requires immediate intervention from more chronic conditions. Perhaps the most important diagnosis to quickly make (or exclude) is that of a septic hip. While a septic joint bears many general similarities to osteomyelitis (see Bone Pain module) in the hip joint, there is an urgency to initiating treatment. Articular cavities provide protected environments for the growth of microorganisms. Pus (bacteria + white blood cells) can rapidly develop and distend the joint. In the hip, this increased intra-articular pressure can threaten the blood supply of the femoral head and cause secondary avascular necrosis of bone. Both bacterial toxins and the products of inflammation are deleterious to articular cartilage causing permanent joint surface damage.
Flynn and Widmann (J Am Acad Orthop Sur 9(2), 2001) identify five essential questions that must be answered to diagnose the source of a limp in a child. Keep these in mind as you work through the remainder of this module. These key questions are:
Pain: Is the limp due to pain?
Onset: Did the limp develop suddenly or gradually, or has it always been there?
