ABPS Orthopedic Surgery cheat sheet
ABPS Orthopedic Surgery · Keep the key ideas within reach.
Orthopedic Surgery Knowledge and Skills (Written Exam)
Salter-Harris classification: I through physis only; II physis plus metaphysis; III physis plus epiphysis; IV through metaphysis, physis, and epiphysis; V physeal crush.
Compartment syndrome pressure threshold: delta pressure (diastolic minus compartment) of 30 mmHg or less supports fasciotomy; absolute pressure over 30 mmHg alone is less reliable.
Open fracture: Gustilo-Anderson grades I (less than 1 cm, clean) through IIIC (vascular injury requiring repair); all open fractures need tetanus status review and early antibiotics.
Cauda equina red flags: saddle anesthesia, bowel or bladder dysfunction, bilateral leg weakness; requires urgent MRI and decompression.
Osteomyelitis: Staphylococcus aureus is the most common pathogen; Salmonella is classically associated with sickle cell disease.
Bone healing: inflammation (days), soft callus (weeks), hard callus, then remodeling; smoking and NSAIDs impair union.
Nerve injuries: radial nerve with humeral shaft fractures; axillary nerve with surgical neck of humerus; peroneal nerve with fibular neck fractures.
Septic arthritis of a native joint: joint aspiration with cell count, Gram stain, and culture; surgical drainage plus IV antibiotics is standard.
Orthopedic Surgery Clinical Practice (Oral Exam)
Case presentation format: history and mechanism, focused exam, imaging interpretation, differential, definitive plan, and complications.
Pediatric fracture decisions hinge on physeal involvement (Salter-Harris), remodeling potential by age, and acceptable displacement for the specific bone.
Hip fracture in the elderly: displaced femoral neck favors arthroplasty; intertrochanteric fractures favor cephalomedullary nailing or sliding hip screw.
Compartment syndrome workup: serial exams, pain with passive stretch, and measured pressures; do not wait for pulselessness.
Knee ligament exam: Lachman most sensitive for ACL; McMurray for meniscal tears; varus/valgus stress at 30 degrees for collateral ligaments.
Antibiotic prophylaxis timing: within 60 minutes before incision; redosing for long cases and significant blood loss.
VTE prophylaxis after major lower-limb arthroplasty: mechanical plus pharmacologic agents per risk stratification; balance bleeding risk.
Document informed consent with risks, benefits, alternatives, and the patient's questions answered in their own words.