Approach
• Examine abdomen, genitalia, spine, hips, long bones, knees, ankle, feet; observe gait
• Careful hx from pt & care giver: Acute vs. chronic, fevers, skin Δ; trauma
• Obtain x-rays although pain is often referred (classically, knee pain referred from hip)
• Consider systemic sxs in conjunction w/ chief complaint of joint pain
INFECTIOUS
Septic Arthritis of the Hip
History
• Most commonly in children <3 y/o, but can occur at any age
• Limp or refuse to walk, h/o fever & irritability (sxs may be far more subtle in infants)
Findings
• Febrile & toxic appearing
• Flexed, externally rotated, abducted hip; antalgic gait (if walking)
• Significant pain w/ ROM but not necessarily warm, swollen or erythematous
Evaluation
• ↑ WBC, ↑ CRP, ↑ ESR; arthrocentesis shows ↑ WBC, +gram stain & culture
• X-rays & U/S may show effusion
Treatment
• Orthopedic consultation for drainage & washout in the OR
• Abx: β-lactamase–resistant PCN (IV nafcillin or oxacillin 50–100 mg/kg/d QID) & 3rd-generation cephalosporin (cefotaxime or ceftriaxone 50 mg/kg); consider vancomycin
• Pain control
Disposition
• Admit for surgical wash-out
Pearl
• Hip > knee > elbow likely to be septic in children
Toxic (Transient) Synovitis
History
• 3–6-y/o boy w/ acute or chronic unilateral hip, thigh, or knee pain
• May be mildly febrile, possibly recent URI
Findings
• Nontoxic appearing
• Limited hip ROM 2/2 pain; mild restriction of passive ROM to abduction & internal rotation; most sens to log roll
• Antalgic gait, painful to palpation
Evaluation
• X-ray of hip nl; may show effusion
• WBC & ESR nl or slightly ↑; afebrile children w/ nl labs can avoid arthrocentesis
• U/S can diagnose effusion, but cannot differentiate type
Treatment
• Pain control w/ NSAIDs, heat, & massage
Disposition
• Orthopedic f/u, crutches to keep weight off hip until pain resolves
Pearls
• Most common cause of acute hip pain in children from 3–10 yr; arthralgia & arthritis secondary to transient inflammation of the synovium of the hip
• Recurrence rate <20%, most develop w/i 6 mo, no ↑ risk for juvenile chronic arthritis
MUSCULOSKELETAL
Legg–Calvé–Perthes Disease (Avascular Necrosis of Femoral Head)
History
• Most commonly in 5–7 y/o w/ limp & pain in groin, thigh, or knee; worse w/ ↑ activity
• No fever or irritability, no h/o trauma
Findings
• Nontoxic appearing, antalgic gait
• ↓ Hip ROM secondary to pain w/ possible thigh atrophy, ↑ w/ internal rotation & abduction
Evaluation
• WBC & ESR nl
• X-rays of hip show progression; frog-leg views helpful
• Widening of cartilage space, diminished ossific nucleus
• Subchondral stress fx of femoral head; linear lucency in femoral head epiphysis
• Femoral head opacification & flattening known as coxa plana
• Subluxation & protrusion of femoral head from acetabulum
Treatment
• Goal is to avoid severe degenerative arthritis, maintain ROM, relieve weight bearing
• Orthopedic eval; bone scan & MRI more rapidly diagnostic than x-rays
Disposition
• Orthopedic f/u, crutches to keep weight off hip until pain resolves
Pearls
• Idiopathic osteonecrosis of capital epiphysis of femoral head; 15–20% bilateral
• Caused by interruption of blood supply to capital femoral head → bone infarction
• Better prognosis at younger onset; proportional to degree of radiologic involvement
Slipped Capital Femoral Epiphysis (SCFE)
History
• 12–15-y/o boy or 10–13-y/o girl, c/o limp & groin, thigh, or knee pain
• If sxs >3 wk, considered chronic
• If unable to bear weight, considered unstable (higher complication rate)
Findings
• Affected leg externally rotated, shortened w/ pain when flexing hip; antalgic gain
Evaluation
• nl temp, WBC, ESR
• X-ray: Femoral head is displaced posteriorly & inferiorly in relation to femoral neck w/i confines of acetabulum; AP & frog-leg views best
Treatment
• Orthopedic consult for operative internal fixation; goal to prevent AVN of femoral head
Disposition
• Admission for orthopedic surgery
Pearls
• Obesity is the RF; genetics plays role; bilaterality more common in younger pts who also tend to have metabolic/endocrine disorders
• If traumatic hip injury w/ obvious external rotation & shortening of the leg, do not force ROM as this can worsen epiphyseal displacement
Osgood–Schlatter Disease
Definition
• Microtrauma to the tibial tubercle tuberosity apophysis occurring during use
History
• Preteen boy w/ knee pain, worse w/ activity & better w/ rest
Findings
• Edema & pain of tibial tubercle; enlarged & indurated tibial tuberosity
• Tender over anterior knee, esp over thickened patellar tendon
• Pain reproduced by extending knee against resistance, stressing quads or squatting w/ knee in full flexion, running, jumping, kneeling, squatting, stairs
Evaluation
• Knee x-ray: Soft tissue swelling over tuberosity & patellar tendon; no effusion
Treatment
• Guided by severity: Range from decreasing activity in mild cases to rest in severe cases
• NSAIDs for pain control, ice, ±crutches
Disposition
• D/c home w/ pain control
Pearls
• One of the most common causes of knee pain in adolescent; benign & self-limited
• Bilateral in 25% of cases; 50% give h/o precipitating trauma