Arab Board Orthopedic Surgery Final cheat sheet

Bone remodeling follows Wolff's law: trabecular orientation aligns with principal stress trajectories; disuse leads to osteopenia.

Haversian system: osteons with concentric lamellae around a central canal containing a capillary and nerve; Volkmann canals connect adjacent osteons.

Fracture healing: hematoma → inflammation (days) → soft callus (weeks) → hard callus (months) → remodeling (years); stability determines primary (direct) vs secondary healing.

Cartilage: avascular, aneural, alymphatic; nutrition by diffusion from synovial fluid; type II collagen predominates in hyaline cartilage.

Nerve injury Seddon classification: neurapraxia (conduction block, full recovery), axonotmesis (axonal disruption, regeneration 1 mm/day), neurotmesis (complete transection, no spontaneous recovery).

Muscle fiber types: Type I slow-twitch oxidative (fatigue-resistant, posture); Type II fast-twitch glycolytic (power, fatigable).

Ligament vs tendon: ligament connects bone to bone (stabilization), tendon connects muscle to bone (force transmission); both are dense regular connective tissue rich in type I collagen.

Stress–strain curve: elastic region (reversible deformation) up to yield point; plastic region (permanent deformation) up to ultimate failure; area under curve = toughness.

Bone blood supply: nutrient artery (diaphyseal), metaphyseal and epiphyseal arteries; periosteal supply critical in children and after intramedullary nailing.

ATLS primary survey: Airway with cervical spine protection, Breathing, Circulation with hemorrhage control, Disability (GCS/pupils), Exposure with temperature control.

Open fracture: urgent IV antibiotics (cefazolin ± aminoglycoside for Gustilo III), tetanus prophylaxis, debridement and irrigation within 6–24 hours, stabilization.

Gustilo–Anderson: I clean wound <1 cm; II 1–10 cm without extensive soft-tissue damage; IIIA adequate soft-tissue coverage; IIIB inadequate coverage requiring flap; IIIC arterial injury requiring repair.

Compartment syndrome: pain out of proportion, pain on passive stretch, paresthesia, pallor, paralysis, pulselessness (late); diagnosis is clinical; fasciotomy is definitive.

Neck of femur fractures: intracapsular (subcapital, transcervical, basicervical) risk avascular necrosis; extracapsular (intertrochanteric, subtrochanteric) typically treated with fixation.

Damage control orthopedics: temporary external fixation for polytrauma patients to minimize second hit; convert to definitive fixation when physiology allows.

Nonunion: no radiographic progression for 3 months; risk factors include infection, instability, poor blood supply, smoking, NSAIDs.

Pediatric physeal fractures: Salter–Harris I–V; type I through physis, II physis + metaphysis, III physis + epiphysis, IV through both, V crush injury.

Pelvic ring injuries: AP compression, lateral compression, vertical shear; hemodynamic instability with pelvic fracture → binder, angiography/embolization or preperitoneal packing.

Total hip arthroplasty bearing options: metal-on-polyethylene (standard), ceramic-on-ceramic (low wear, squeak risk), dual mobility (reduces dislocation in high-risk patients).

THA dislocation risk: posterior approach higher than anterior/lateral; precautions include avoidance of hip flexion >90°, adduction, internal rotation.

Aseptic loosening: most common cause of late THA/TKA failure; radiographic signs include progressive radiolucent lines, component migration, osteolysis.

Periprosthetic joint infection: diagnosis with MSIS/ICM criteria (ESR, CRP, synovial WBC, PMN%, culture, alpha-defensin); two-stage exchange for chronic infection.

TKA alignment: mechanical axis aims for neutral (0°); coronal plane femoral component 5–7° valgus relative to anatomic axis; tibial component perpendicular to mechanical axis.

Unicompartmental knee arthroplasty indications: isolated medial compartment OA, intact ACL, correctable deformity <15°, BMI <35, age >60.

Hip resurfacing: preserves femoral bone stock; higher revision risk in women and small component sizes; metal ion surveillance required.

Antibiotic prophylaxis: cefazolin within 60 minutes before incision; vancomycin if MRSA colonization; redosing for long procedures.

Venous thromboembolism prophylaxis after arthroplasty: aspirin, LMWH, or DOAC for 10–35 days depending on risk; early mobilization.

Cauda equina syndrome: saddle anesthesia, bowel/bladder dysfunction, bilateral leg weakness; emergent MRI and decompression within 24–48 hours.

Cervical myelopathy: gait disturbance, hand clumsiness, hyperreflexia, Hoffmann sign, inverted brachioradialis reflex; MRI shows cord compression ± T2 signal change.

Lumbar disc herniation: posterolateral herniation compresses traversing nerve root (L4–L5 disc → L5 root); far lateral compresses exiting root.

Scoliosis: Cobb angle >10° defines scoliosis; >25° bracing, >45–50° surgical consideration in adolescents.

Thoracolumbar fracture classification: TLICS score (morphology, posterior ligamentous complex, neurologic status); score ≥5 suggests surgery.

Spinal cord injury: ASIA impairment scale A (complete) to E (normal); neurogenic shock (bradycardia, hypotension) vs spinal shock (flaccid paralysis, loss of reflexes).

Odontoid fracture types: I avulsion tip, II base of dens (highest nonunion), III through body of C2.

Spinal epidural abscess: fever, back pain, neurologic deficit; emergent MRI and decompression with antibiotics.

Degenerative spondylolisthesis: typically L4–L5; Meyerding grading I–V; fusion with decompression for instability.

ACL tear: positive Lachman (most sensitive), anterior drawer, pivot shift; MRI confirms; reconstruction with autograft (hamstring or BTB) for young active patients.

Meniscal tear: McMurray test, joint line tenderness; conservative for degenerative tears in older adults; repair for peripheral vascular zone tears in young.

Rotator cuff tear: painful arc, drop arm test, Jobe (empty can) for supraspinatus; MRI or ultrasound; repair for acute full-thickness tears in active patients.

Shoulder instability: anterior dislocation (Bankart lesion, Hill–Sachs), posterior (reverse Bankart, reverse Hill–Sachs); apprehension test.

Ankle sprain: lateral ligament complex (ATFL most commonly injured); Ottawa ankle rules to decide imaging.

Patellofemoral pain: anterior knee pain, positive patellar grind; conservative management with quadriceps strengthening.

Achilles tendon rupture: positive Thompson test, palpable gap; surgical repair vs functional bracing.

Hip labral tear: anterior hip pain, positive FADIR; MR arthrogram; arthroscopic debridement/repair.

Concussion in sport: SCAT5 assessment; return-to-play protocol stepwise after symptom resolution.

Developmental dysplasia of the hip (DDH): Ortolani and Barlow tests in neonates; Pavlik harness for <6 months; ultrasound screening.

Legg–Calvé–Perthes disease: avascular necrosis of femoral head in children 4–8 years; containment treatment; Stulberg classification for outcome.

Slipped capital femoral epiphysis (SCFE): obese adolescent, hip/groin pain, limited internal rotation; frog-leg lateral radiograph; in situ pinning.

Clubfoot (talipes equinovarus): Ponseti method (serial casting, Achilles tenotomy, bracing); initial treatment within first weeks of life.

Limb length discrepancy: scanogram; growth arrest lines (Harris lines); epiphysiodesis for predicted discrepancy.

Osteogenesis imperfecta: brittle bones, blue sclerae, dentinogenesis imperfecta; bisphosphonates and intramedullary rodding.

Pediatric supracondylar humerus fracture: extension type most common; Gartland classification; neurovascular assessment (anterior interosseous nerve).

Septic arthritis of hip in child: Kocher criteria (fever, non-weight-bearing, ESR, WBC); urgent aspiration and IV antibiotics.

Scoliosis screening: Adams forward bend test; referral for Cobb >20° or rapid progression.

Carpal tunnel syndrome: median nerve compression; night pain, thenar atrophy, positive Phalen/Tinel; EMG/NCS; release of transverse carpal ligament.

Dupuytren contracture: palmar fascia fibrosis; tabletop test; treatment with collagenase, needle aponeurotomy, or fasciectomy.

Scaphoid fracture: tenderness in anatomic snuffbox; risk of nonunion and AVN (proximal pole); MRI or repeat radiographs; cast or screw fixation.

Distal radius fracture: Colles (dorsal angulation) vs Smith (volar angulation); volar locking plate for unstable fractures.

Trigger finger: A1 pulley stenosis; corticosteroid injection; surgical release if recurrent.

De Quervain tenosynovitis: Finkelstein test; thumb abductor/extensor pollicis brevis; splint and injection.

Nerve lacerations: primary repair within 72 hours for clean cuts; nerve grafting for gaps >2 cm; sensory re-education.

Flexor tendon repair: zone II (no man's land); core suture with epitendinous repair; early controlled mobilization.

Radial nerve palsy: wrist drop; humeral shaft fracture (Holstein–Lewis); observation for closed fractures, exploration for open.

Ankle fracture: Weber classification (A below syndesmosis, B at, C above); syndesmotic injury requires screw fixation.

Achilles tendinopathy: eccentric loading exercises; insertional vs non-insertional; avoid corticosteroid injections (rupture risk).

Plantar fasciitis: morning pain, medial calcaneal tubercle tenderness; conservative treatment (stretching, orthoses).

Hallux valgus: first metatarsal osteotomy (chevron, scarf) for symptomatic; bunionectomy; assess intermetatarsal angle.

Flatfoot: flexible vs rigid; rigid flatfoot (tarsal coalition) requires imaging; flexible often asymptomatic.

Diabetic foot ulcer: offloading, debridement, infection control; Charcot arthropathy (midfoot collapse, rocker-bottom).

Lisfranc injury: midfoot instability; weight-bearing radiographs; ORIF or primary arthrodesis.

Ankle arthrodesis vs arthroplasty: arthrodesis for young/active, arthroplasty for older low-demand.

Tarsal tunnel syndrome: tibial nerve compression; burning heel pain, positive Tinel; release of flexor retinaculum.

Osteosarcoma: bimodal age (children/adolescents and elderly); metaphysis of long bones; sunburst periosteal reaction, Codman triangle; neoadjuvant chemo + limb salvage.

Ewing sarcoma: diaphysis, small round blue cells, t(11;22); onion-skin periosteal reaction; chemo + surgery/radiation.

Giant cell tumor: epiphysis of long bones, soap-bubble appearance; receptor activator of NF-κB ligand (RANKL) inhibitor denosumab.

Osteochondroma: most common benign bone tumor; cartilage cap; risk of malignant transformation (chondrosarcoma) if rapid growth.

Multiple myeloma: lytic lesions, anemia, renal failure, hypercalcemia; serum protein electrophoresis, Bence Jones proteins.

Bone metastases: most common from breast, prostate, lung, kidney, thyroid; pathologic fracture risk (Mirels score).

Paget disease: mosaic pattern of lamellar bone, elevated alkaline phosphatase; risk of osteosarcoma and secondary arthritis.

Osteoporosis: DEXA T-score ≤ −2.5; bisphosphonates, calcium, vitamin D; FRAX for fracture risk.

Rickets/osteomalacia: defective mineralization; bowing, widened growth plates; vitamin D deficiency; treatment with vitamin D and calcium.

Osteomyelitis: acute hematogenous (children, metaphysis) vs chronic; Staphylococcus aureus most common; MRI for diagnosis, bone biopsy for culture.

Septic arthritis: urgent joint aspiration; Gram stain and culture; IV antibiotics; surgical lavage.

Prosthetic joint infection: early (<3 months), delayed (3–12 months), late (>12 months); debridement with implant retention for acute, two-stage exchange for chronic.

Necrotizing fasciitis: rapidly spreading, pain out of proportion, systemic toxicity; emergent surgical debridement.

Gas gangrene: Clostridium perfringens; crepitus, myonecrosis; high-dose penicillin and debridement.

Tuberculous arthritis: chronic monoarthritis, Poncet disease; synovial biopsy; quadruple anti-tuberculous therapy.

HIV and orthopedic infection: higher risk of septic arthritis and osteomyelitis; consider atypical organisms.

Antibiotic beads: PMMA impregnated with vancomycin/tobramycin for dead space management.

Surgical site infection prevention: chlorhexidine skin prep, prophylactic antibiotics, normothermia, glycemic control.

Early mobilization after fracture fixation reduces DVT, pneumonia, and pressure ulcers.

Range of motion: passive, active-assisted, active, resisted; progression based on tissue healing.

Strength training: isometric (no joint motion), isotonic (constant load), isokinetic (constant velocity).

Gait training: non-weight-bearing, partial, weight-bearing as tolerated; assistive devices (walker, crutches, cane).

Amputation rehabilitation: stump shaping, desensitization, prosthetic fitting when wound stable and edema controlled.

Cardiopulmonary rehabilitation in orthopedic patients: incentive spirometry, breathing exercises to prevent atelectasis.

Pain management: multimodal analgesia (opioids, NSAIDs, acetaminophen, regional blocks) to reduce opioid dependence.

Return to sport: functional testing, sport-specific drills, psychological readiness.

Below-knee prosthesis: patellar tendon-bearing socket; energy-storing foot for active users.

Above-knee prosthesis: quadrilateral or ischial containment socket; knee units (single-axis, polycentric, microprocessor).

Orthoses: AFO for foot drop; KAFO for knee instability; TLSO for thoracic spine support.

Prosthetic prescription: consider patient's age, activity level (K-level), residual limb condition, and goals.

Osseointegration: direct skeletal attachment of prosthesis; reduces socket-related problems; risk of infection.

Upper limb prosthetics: body-powered (cable) vs myoelectric; terminal devices (hook, hand).

Orthotic principles: three-point pressure system for deformity correction; total contact for load distribution.

Rehabilitation after amputation: pre-prosthetic training, strengthening, balance, gait training with prosthesis.

Informed consent: disclosure of diagnosis, treatment options, risks, benefits, and alternatives; patient competence and voluntariness.

Confidentiality: protect patient health information; exceptions for public safety, communicable diseases, and legal requirements.

Medical errors: disclose to patient and family; root cause analysis; culture of safety and non-punitive reporting.

Conflict of interest: disclose financial relationships with industry; avoid undue influence on clinical decisions.

Patient safety: WHO surgical safety checklist (sign in, time out, sign out) reduces complications.

Professional boundaries: avoid dual relationships; maintain appropriate doctor–patient relationship.

End-of-life care: advance directives, do-not-resuscitate orders, palliative care.

Research ethics: institutional review board approval, informed consent, data integrity.