Orthopedic surgery Study Guide

📖 Core Concepts Orthopedic surgery – medical specialty focused on the musculoskeletal system (bones, joints, muscles, tendons, ligaments, nerves). Arthroplasty – surgical replacement, remodeling, or realignment of a joint’s articular surface. Arthroscopy – minimally‑invasive “keyhole” technique using a camera and small instruments to treat intra‑articular pathology. Intramedullary fixation – placement of a metal rod inside the medullary canal to stabilize long‑bone fractures without opening the fracture site. External fixation (Ilizarov) – circular frame with tensioned wires/spokes that holds bone fragments externally, allowing realignment, lengthening, and healing. Total vs. partial joint replacement – total replaces all weight‑bearing surfaces; unicompartmental (partial) replaces only one compartment. Surgeon volume effect – higher‑volume orthopedic surgeons have lower revision‑surgery rates and better outcomes. --- 📌 Must Remember Thomas splint reduced open femur‑fracture mortality from 87 % → <8 % (WWI). Küntscher intramedullary rod introduced during WWII; modern percutaneous technique popularized in the 1970s. Charnley low‑friction THR (1960s) = stainless‑steel stem + polyethylene cup + PMMA cement. Ilizarov fixator = circular external device, tensioned spokes = “bicycle‑wheel” principle. Arthroscopy → return to normal activities days vs. weeks/months for open surgery. Unicompartmental knee replacement → higher revision risk than total knee replacement. Opioid prescribing – orthopedists are among the highest prescribers; current emphasis on reduction strategies. Residency pathway (US): 4 yr undergrad → 4 yr med school → 5 yr ortho residency (highly competitive). Board certification requires written + oral exams covering six‑month clinical/surgical performance. --- 🔄 Key Processes Thomas Splint Application Position patient supine, pad femur, apply traction via splint, secure distal leg, maintain continuous traction. Percutaneous Intramedullary Fixation Guide‑wire insertion → ream canal (if needed) → insert rod → lock proximally & distally → confirm alignment radiographically. Ilizarov Bone Lengthening Attach rings to bone with wires/pins → create controlled distraction (≈1 mm/day) → monitor regenerate bone formation via radiographs. Arthroscopic Knee Meniscectomy Insert arthroscope → visualize joint → resect torn meniscal fragment with shaver → lavage and close portals. Total Hip Replacement (Charnley) Remove femoral head → prepare acetabular socket → insert cemented polyethylene cup → insert cemented femoral stem → reduce hip. --- 🔍 Key Comparisons Thomas splint vs. Modern traction Thomas splint: static, external, reduces mortality in femur fractures. Modern traction: often skeletal (e.g., pins) with adjustable forces; used for various long‑bone injuries. Intramedullary fixation vs. External fixation IM fixation: internal rod, less soft‑tissue disruption, earlier weight‑bearing. Ilizarov: external frame, useful for severe comminution, deformity correction, lengthening. Total knee replacement vs. Unicompartmental knee replacement TKA: replaces all compartments, lower revision risk. UKA: replaces only one compartment, preserves bone, but higher revision risk. Arthroscopy vs. Open surgery Arthroscopy: small incisions, faster rehab, less pain. Open: larger exposure, longer rehab, sometimes required for complex reconstructions. --- ⚠️ Common Misunderstandings “All arthroplasties are the same.” – Material (polyethylene, metal, ceramic), fixation (cemented vs. cementless), and bearing design (fixed vs. mobile) vary widely. “External fixators are only for temporary stabilization.” – Ilizarov frames can be definitive treatment for lengthening or severe deformity. “Higher surgeon volume only matters for complex cases.” – Volume correlates with lower revision rates across all joint replacements. “Arthroscopy is always safer than open surgery.” – Improper portal placement or insufficient visualization can lead to missed pathology or neurovascular injury. --- 🧠 Mental Models / Intuition “Bike wheel” model for Ilizarov: tensioned spokes keep the frame rigid; adjust tension to control distraction and alignment. “Plug‑and‑play” for joint replacement: think of the joint as a socket‑plug system – the acetabular cup (socket) mates with the femoral stem head (plug). “Inside‑out vs. outside‑in fixation”: Intramedullary = inside‑out (rod inside bone); Ilizarov = outside‑in (frame outside bone). --- 🚩 Exceptions & Edge Cases Unicompartmental knee replacement is contraindicated in patients with ligamentous instability or inflammatory arthritis. Intramedullary rods should not be used in pathologic fractures from tumor or severe osteoporosis without augmentation. Opioid‑sparring protocols may be limited in patients with severe acute pain post‑trauma; multimodal analgesia is preferred but not always feasible. --- 📍 When to Use Which Fracture stabilization Simple diaphyseal femur/tibia fracture → percutaneous intramedullary rod. Comminuted, segmental, or length‑requiring fracture → Ilizarov external fixator. Joint replacement choice Isolated medial compartment arthritis, intact cruciate ligaments → consider unicompartmental knee replacement. Multicompartmental arthritis, ligament deficiency, or severe deformity → total knee replacement. Arthroscopy vs. Open Isolated meniscal tear, chondral lesion, or simple ligament reconstruction → arthroscopy. Complex multi‑structure injuries, large osteochondral defects → open approach. --- 👀 Patterns to Recognize Historical mortality drop → Whenever a new stabilization device (Thomas splint, intramedullary rod) is introduced, look for dramatic reduction in infection/mortality rates. Volume‑outcome relationship – High‑volume surgeons repeatedly appear in studies with lower revision and better functional scores. Pain‑management trends – Questions linking orthopedic surgery with opioid prescribing often probe prescription reduction strategies. --- 🗂️ Exam Traps “All external fixators are temporary.” – Ilizarov can be definitive for lengthening; the trap is assuming it’s only a bridge. “Unicompartmental knee replacement always has fewer complications.” – Actually carries higher revision risk; the distractor may cite “preserves bone” without mentioning revision data. “Thomas splint is obsolete.” – While modern devices exist, the key exam point is its historic impact on mortality reduction; answer choices that downplay this are traps. “Arthroscopy always leads to faster recovery.” – Generally true, but certain complex reconstructions may still require open surgery; a trap would be “Arthroscopy is appropriate for all knee injuries.” ---