Category	History	Physical examination may show	Laboratory studies	Radiology
Traumatic	Fall	Localized pain, swelling, loss of motion	None unless infection is possible	Plain films, bone scan
Infectious	Fever, chills, erythema, pain	Rigid guarding, warmth, erythema	CBC, ESR, CRP, joint aspirate	Plain films, MRI, bone scan
Neoplastic	Night pain, pain unrelated to activity	Mass	CBC, ESR, CRP, alkaline phosphatase, calcium, electrolytes, joint aspirate	Plain films, MRI/CT, bone scan, staging work-up
Congenital	Problem since birth	Deformity, leg-length discrepancy, loss of ROM	None	Plain films
Neurologic	Ataxia, loss of balance, disorganized gait	High/low muscle tone, increased/decreased deep tendon reflexes, cavus foot or claw toes	Creatine kinase (if DMD is in differential diagnosis)	Plain films
Inflammatory	Pain > 6 months, family history of rheumatoid arthritis	Warmth/erythema, one or more joints	CBC, ESR, CRP, joint aspiration	Plain films
Developmental	Painless limp (LCP disease) Knee pain (LCP disease, SCFE)	Loss of ROM in joints, asymmetric ROM, pain with ROM	None	Plain films