Orthopaedic Nursing Practice
What this domain tests
Orthopaedic Nursing Practice is the clinical core of the ONC exam: assessment and monitoring of patients with musculoskeletal injury, surgery, or chronic disease. Items cluster around neurovascular assessment, compartment syndrome, fat embolism, VTE prevention, cast and traction care, and joint-replacement precautions.
Core rules
- Perform and document a full neurovascular check (the Ps: pain, pallor, paresthesia, paralysis, pulselessness, plus temperature and capillary refill) on every injured or postoperative limb, and compare with the baseline and the opposite limb.
- Pain out of proportion to the injury and pain on passive stretch are the earliest signs of compartment syndrome. Pulses often remain palpable, so a palpable pulse never rules it out.
- Compartment pressure greater than 30 mmHg (or within 30 mmHg of diastolic) is treated as an emergency: notify the surgeon, remove constricting bandages or casts, and prepare for fasciotomy. Keep the limb at heart level, not elevated above it, because elevation lowers perfusion pressure.
- Fat embolism typically appears 24-72 hours after a long-bone fracture with hypoxemia, petechiae, and confusion; treatment is supportive oxygen and stabilization.
- VTE prophylaxis is both mechanical and pharmacologic; monitor for bleeding and for signs of DVT or PE.
- Posterior-approach hip replacement precautions: no hip flexion beyond 90 degrees, no adduction past midline, no internal rotation.
Worked example
A patient 6 hours after tibial nailing reports escalating pain, has a tense calf, and winces when the toes are passively extended. Pedal pulses are 2+ and capillary refill is 2 seconds. The priority is compartment syndrome, not fracture pain. The presence of pulses does not exclude it, and the passive-stretch pain is a red flag. The nurse should notify the surgeon immediately, loosen the dressing, keep the leg at heart level, and prepare for pressure measurement and possible fasciotomy.
Traps that cost marks
Equating palpable pulses with adequate perfusion; elevating the limb above heart level during suspected compartment syndrome; attributing hypoxia and confusion only to pain medication instead of considering fat embolism; and applying posterior hip precautions to an anterior-approach replacement.