ONC® Certification flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Compartment syndrome early sign

Pain out of proportion to the injury, worsened by passive stretch of the muscles in the compartment, is the earliest reliable sign; pulselessness and paralysis occur late.

Delta pressure threshold

Diastolic blood pressure minus compartment pressure. A value below 30 mmHg in a symptomatic limb supports urgent fasciotomy and should be reported immediately.

Fat embolism syndrome triad

Hypoxemia, petechial rash, and neurologic changes appearing 24-72 hours after long-bone fracture. Falling platelets and fever may accompany the triad.

Osteomyelitis common pathogen

Staphylococcus aureus is the most frequent cause of acute and chronic bone infection. Chronic cases require bone biopsy culture rather than a sinus-tract swab.

Avascular necrosis sites

Femoral head, scaphoid proximal pole, talar body, and lunate are prone to avascular necrosis because blood supply is tenuous and enters distally.

Hip fracture limb position

A displaced femoral neck or intertrochanteric fracture typically produces a shortened leg held in external rotation, unlike a posterior dislocation with internal rotation.

Bone healing phases

Hematoma and inflammation, soft callus, hard callus, then remodeling. Smoking, poor nutrition, and some medications delay union.

Neurovascular check elements

Document color, temperature, capillary refill, pulses, sensation, and motor function, comparing with the unaffected limb, before and after casts or surgery.

Cast compartment warning

Unrelieved pain, burning, numbness, or pallor under a cast signals pressure or ischemia; the cast must be split or bivalved and the surgeon notified.

Osteoarthritis radiographic features

Joint-space narrowing, subchondral sclerosis, osteophytes, and subchondral cysts. Pain worsens with activity and improves with rest.

Rheumatoid arthritis features

Symmetric small-joint synovitis with morning stiffness lasting over an hour, positive rheumatoid factor or anti-CCP, and possible cervical spine instability.

Osteoporosis DXA threshold

A T-score of -2.5 or lower defines osteoporosis. A hip or vertebral fragility fracture establishes the diagnosis regardless of bone density.

Posterior hip precautions

Avoid hip flexion beyond 90 degrees, adduction past midline, and internal rotation after posterior-approach arthroplasty; use an abduction wedge in bed.

Knee arthroplasty priorities

Early ambulation, range-of-motion exercise, and monitoring for deep vein thrombosis, peroneal nerve palsy, and wound drainage after total knee replacement.

Open fracture first steps

Check tetanus status, give antibiotics within one hour, and arrange urgent irrigation and debridement. Gustilo grading guides fixation and soft-tissue coverage.

Septic arthritis findings

Joint aspiration showing a white count often above 50,000/mm3 with neutrophil predominance. Urgent drainage and intravenous antibiotics are required.

Scoliosis screening test

The Adams forward bend test detects rotational deformity. Curves of 25-40 degrees in a growing child may be treated with bracing to limit progression.

Spinal fusion nursing care

Use log-roll technique, monitor neurologic status, and assess bowel function because ileus is common, especially after anterior spinal approaches.

Paget disease laboratory pattern

Elevated alkaline phosphatase with normal calcium and phosphorus. Bone pain, bowing, and pathologic fracture or osteosarcoma risk may occur.

Multimodal analgesia concept

Combine scheduled acetaminophen and appropriate NSAIDs with regional blocks and opioids only for breakthrough pain to reduce opioid dose and adverse effects.

Opioid respiratory depression clue

Sedation and decreasing respiratory rate precede hypoxemia. Monitor level of consciousness and breathing, and have naloxone available per protocol.

Local anesthetic systemic toxicity

Tinnitus, metallic taste, confusion, and seizures after regional anesthesia. Stop injection, support airway, and give lipid emulsion per protocol.

Pulmonary embolism signs

Sudden dyspnea, tachycardia, chest pain, and hypoxemia after arthroplasty. Confirm platelet count before starting heparin to exclude heparin-induced thrombocytopenia.

Rhabdomyolysis management

Dark urine, elevated creatine kinase, and hyperkalemia after crush injury or prolonged immobility. Treat with aggressive intravenous fluids and monitor renal function.

Cauda equina red flags

Saddle anesthesia, new bladder or bowel dysfunction, and bilateral leg weakness require emergency MRI and surgical referral to prevent permanent deficit.

Skeletal pin site care

Clean daily with the prescribed solution, keep the site dry, and report loosening, redness, or drainage. Routine antibiotic ointment is used only if ordered.

Ilizarov distraction rate

After a latency of several days, distraction proceeds about 1 mm per day in divided increments, followed by a consolidation phase before frame removal.

Crutch fitting rule

Hand grips at wrist level with elbows flexed 15-30 degrees. Going upstairs, lead with the unaffected leg; going downstairs, lead with the affected leg.

Cane use rule

Hold the cane in the hand opposite the affected limb and advance it with the involved leg to widen the base of support and reduce joint load.

Salter-Harris classification

Types I through V describe physeal fractures by involvement of physis, metaphysis, and epiphysis. Higher types carry greater risk of growth disturbance.

Autonomic dysreflexia response

With spinal injury at T6 or above, hypertension and pounding headache from bladder or bowel distension require sitting upright and relieving the stimulus immediately.

Ankle sprain Ottawa rules

Ankle x-ray is indicated with malleolar pain plus bone tenderness at specified landmarks or inability to bear weight four steps immediately and in the clinic.