A patient who fell onto the lower leg reports diffuse pain and tightness that is relieved by rest and increases with activity and stretching. Bone scans are negative and muscle strength is grossly normal. Which condition is most likely?

• A. Tibial osteosarcoma
• B. Tibial stress fracture
• C. Compartment syndrome
• D. Achilles tendon rupture

Answer: (C)

Compartment syndrome is suggested when there is leg trauma followed by pain and a sense of tightness that is out of proportion to exam and worsens with activity or stretching, even if strength remains normal and imaging is unrevealing. In the early phase after an injury, increased pressure within a closed muscle compartment can cause diffuse pain and tightness that intensifies with use, while pulses and motor function can still be preserved. Bone scans may be negative in this early period because the problem is pressure-related rather than a bone lesion, and the absence of focal tenderness makes a stress fracture less likely. Achilles tendon rupture would typically present with sudden difficulty in plantarflexion, and tibial stress fracture usually shows focal tenderness along the bone and often becomes evident on further imaging; osteosarcoma would not present acutely after a fall with relief from rest and normal strength. The hallmark signs here point to compartment syndrome, a condition requiring urgent assessment and treatment to prevent nerve or muscle damage.