10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The ONC exam has 150 questions and runs 3 hours.
These 10 free ONC questions are organized by exam domain, so you can see how each part of the Orthopaedic Nurse - Certified blueprint is tested. Reveal the answer and explanation under each question.
During follow-up for knee osteoarthritis, a 64-year-old says, "I stopped walking because the ache means I am grinding the joint away." Examination is unchanged, and brief discomfort after activity settles with rest. The patient wants to keep shopping independently. Which plan best supports that goal?
Correct answer: C - Agree on short, paced walks and progress activity as tolerated.
At discharge after a posterior-approach total hip arthroplasty, a patient has prescribed posterior hip precautions and is practicing dressing without help. Which technique is appropriate for putting on socks?
Correct answer: D - Use a sock aid while sitting upright on a firm, raised chair.
A patient reports aching in both calves while standing in a queue and while walking. Simply stopping but remaining upright does not help; sitting or leaning forward over a shopping cart brings relief. Distal pulses are palpable, and there is no new weakness or bladder change. Which mechanism best explains the positional pattern?
Correct answer: A - Compression of lumbar nerve roots causing neurogenic claudication
At the first home visit after total knee arthroplasty, a patient demonstrates knee flexion to 105 degrees but lacks 12 degrees of passive extension. The patient sleeps with a rolled pillow directly behind the knee. The rehabilitation plan calls for restoring extension without forceful stretching. Which change most directly addresses the measured deficit?
Correct answer: A - Support the distal calf with the heel free and the knee allowed to straighten.
After fixation of a tibial-shaft fracture, a patient develops a tense calf and increasing pain despite analgesia. Passive toe extension causes marked pain, although the pedal pulse remains palpable. At the time of compartment-pressure measurement, blood pressure is 116/60 mmHg and compartment pressure is 36 mmHg. Which interpretation of the compartment perfusion pressure (delta pressure) should the nurse communicate?
Correct answer: A - 24 mmHg; urgent surgical reassessment is indicated.
Eight weeks after a distal-radius fracture, radiographs show satisfactory healing, but severe burning pain extends throughout the hand. Contact from a sleeve is painful. The hand is swollen, warmer and sweatier than the other hand, and wrist motion is markedly limited. There is no fever, and perfusion is intact. This combination most strongly suggests:
Correct answer: C - Complex regional pain syndrome
An ankle-injury assessment in an alert 26-year-old documents pain in both the malleolar and midfoot zones, focal navicular tenderness, and no bony tenderness at either posterior malleolar edge or tip or at the base of the fifth metatarsal. The patient took four weight-bearing steps immediately after the injury and again at assessment. The examination is otherwise reliable. Under the adult Ottawa rules, which radiographs are indicated?
Correct answer: B - Foot radiographs only
A patient with rheumatoid arthritis who receives a tumor necrosis factor inhibitor develops an acutely swollen, intensely painful native knee and a temperature of 38.3°C (100.9°F). The aspirate contains 32,000 leukocytes/µL and calcium pyrophosphate crystals; Gram stain shows no organisms, and cultures are pending. Which conclusion is justified at handoff?
Correct answer: D - Septic arthritis remains possible despite the crystals and preliminary test results.
An untreated 69-year-old postmenopausal woman has a femoral-neck T-score of -2.1 and no prior fragility fracture. Her U.S.-adapted FRAX estimates are 4.2% for hip fracture and 16% for major osteoporotic fracture over 10 years. Under Bone Health and Osteoporosis Foundation guidance, how should the nurse interpret these results?
Correct answer: B - The hip-fracture risk supports a discussion of medication with the prescriber.
A 13-year-old with obesity comes to clinic for three weeks of right knee pain and a new limp. Knee examination is unremarkable. The right hip has limited internal rotation, and the leg turns outward when the hip is flexed. The adolescent can still walk using crutches. Before obtaining further gait observations, the nurse should:
Correct answer: D - Do not let the patient bear weight; arrange urgent orthopaedic assessment.
The ONC exam also covers these domains. Drill them in the full free practice test:
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