Non-inflammatory Musculoskeletal and Bone Disorders, Including Pain Amplification
Normal variants and structural disease
Growing pains are bilateral, occur late in the day in the calves and thighs, spare the joints, and resolve by morning with a normal examination. Osgood-Schlatter and Sever disease are traction apophysitides. Slipped capital femoral epiphysis presents in adolescence with hip or referred knee pain and limited internal rotation; Legg-Calvé-Perthes disease affects younger children. Chronic recurrent multifocal osteomyelitis (CRMO) causes insidious bone pain, often clavicular or metaphyseal, with characteristic MRI STIR lesions and normal or mildly raised inflammatory markers.
Pain amplification
Amplified musculoskeletal pain syndrome, including localized complex regional pain syndrome, is common and disabling. The history shows pain out of proportion to findings; the examination is incongruent - tenderness that shifts with distraction, allodynia, and preserved function when unobserved. Inflammatory markers and imaging are normal. Management is rehabilitative: graded return to activity, physical and occupational therapy, cognitive behavioral therapy, sleep hygiene, and school re-engagement. Opioids and escalating imaging are harmful.
Traps
Do not diagnose growing pains with unilateral pain, morning stiffness, joint swelling, or fever. A normal ESR and CRP do not exclude early inflammatory disease, though they support a noninflammatory explanation when the history fits.
Rule of thumb
Pain that improves with distraction and worsens with light touch is amplified pain, not arthritis.