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Aseptic Loosening in Arthroplasty
Most common cause of late arthroplasty failure. Pathophysiology: particle-induced macrophage activation → cytokine release → osteolysis. Risk factors: polyethylene wear, malalignment, micromotion, poor cementing technique. Clinical: pain, progressive radiolucent lines, migration. Management: revision arthroplasty with improved fixation and bearing surfaces.
Open topicAtlantoaxial Instability — Pediatric & RA
Causes: congenital anomalies (Down syndrome), os odontoideum, trauma, and rheumatoid arthritis with transverse ligament incompetence. Measure atlantodental interval (ADI): >3 mm in adults or >5 mm in children suggests instability; consider dynamic flexion–extension views. Symptoms: neck pain, myelopathy signs, vertebrobasilar symptoms; intubation risks in RA. Surgery: posterior C1–C2 fusion (Goel‑Harms C1 lateral mass–C2 pedicle/pars screws) ± transarticular screws; consider odontoidectomy for i...
Open topicAvascular Necrosis (AVN) Hip — Ficat & ARCO
AVN = ischemic necrosis of femoral head → collapse and arthritis. Risk factors: steroids, alcohol, trauma, sickle cell, Gaucher’s, idiopathic. Ficat staging I–IV; ARCO integrates imaging and lesion size/location. MRI is most sensitive investigation (double-line sign). Management: early—bisphosphonates, core decompression; late—osteotomy, resurfacing, THA.
Open topicBado Classification — Monteggia Fracture-Dislocations
I: anterior radial head dislocation (ulna angulated anterior). II: posterior; III: lateral; IV: both bones fractured with radial head dislocation. ORIF ulna restores radial head reduction; direction predicts associated patterns.
Open topicBado Classification (Paediatric) — Monteggia & Equivalents
Type I: Anterior radial head dislocation with anterior angulated ulnar fracture — most common in children. Type II: Posterior/posterolateral dislocation; Type III: Lateral/anterior-lateral dislocation; Type IV: Both-bone fractures + radial head dislocation. Equivalents: Variants with plastic deformation or isolated ulna fracture + radial head dislocation; must realign ulna to reduce radius.
Open topicBearing Surfaces in Hip Arthroplasty (MoM, MoP, CoC, CoP)
Main bearing couples: Metal-on-Polyethylene (MoP), Metal-on-Metal (MoM), Ceramic-on-Ceramic (CoC), Ceramic-on-Polyethylene (CoP). MoP: gold standard; risk of wear/osteolysis; improved with highly crosslinked PE. MoM: large heads, low wear but metal ions, ALTR, pseudotumors; largely abandoned. CoC: lowest wear; risk of squeaking, fracture. CoP: good compromise — low wear, no squeaking; increasingly preferred.
Open topicBiceps Pathology — SLAP Lesions
SLAP = Superior Labrum Anterior to Posterior tear involving biceps anchor. Mechanism: overhead throwing, fall on outstretched hand. Types I–IV (Snyder classification). Clinical: pain, clicking, instability; O’Brien’s, crank, biceps load tests. Management: conservative first; arthroscopic repair/debridement in symptomatic tears.
Open topicBiomaterials in Orthopaedics
Metals: stainless steel (316L), cobalt‑chrome, titanium alloys; differences in modulus, corrosion resistance, MRI artifacts. Polymers: UHMWPE (arthroplasty bearings), PMMA (bone cement), PEEK (spacers). Ceramics: alumina/zirconia (bearings), hydroxyapatite/tricalcium phosphate (coatings, bone graft substitutes). Surface engineering: porous coatings, grit‑blast, plasma spray HA for osseointegration. Failure modes: wear (PE oxidation), corrosion (fretting, crevice, galvanic), fatigue fracture, ost...
Open topicBiomechanics of Fracture Fixation
Load sharing vs load bearing; absolute vs relative stability; primary vs secondary healing. Plates: compression (DCP/LCP in compression) vs bridging (relative stability); working length matters. Nails: intramedullary load‑sharing devices; reamed vs unreamed; interlocking controls length/rotation. External fixation: pin density/configuration, frame stiffness; circular frames allow controlled micromotion. Screw biomechanics: lag by technique vs design; pull‑out strength depends on cortical engagem...
Open topicBiopsy Principles in MSK Oncology
Biopsy is critical for diagnosis but must follow strict oncological principles. Plan biopsy with final surgery in mind; incision should be longitudinal and in line with resection. Avoid contamination of uninvolved compartments and neurovascular structures. Prefer core needle/incisional biopsy; excisional only for small superficial masses. Send adequate tissue for histopathology, culture, cytogenetics.
Open topicBlount’s Disease — Langenskiöld Classification
Pathologic varus from disordered endochondral growth of medial proximal tibial physis; early walkers/obesity risk. **Langenskiöld stages I–VI** describe progressive physeal/epiphyseal changes (beaking → depression → physeal bar). Differentiate from physiologic bowing using **metaphyseal–diaphyseal angle** (>11° suggests Blount). Management: **Bracing** in early Stage I–II (
Open topicBöhler Braun Splint — Set-up
Used for tibia/femur fractures with traction. Has pulleys, slings; allows elevation and adjustment. Complications: sores, stiffness, peroneal palsy.
Open topicBone & Joint Infections in HIV
HIV patients prone to bacterial (Staph aureus), mycobacterial (TB), fungal infections. Salmonella is a classic cause of osteomyelitis in HIV, especially with sickle cell disease. Clinical: insidious bone/joint pain, fever, constitutional symptoms; consider atypical presentations. Investigations: cultures, biopsy, imaging (MRI sensitive for marrow involvement). Treatment: prolonged targeted antibiotics, ATT/antifungals as needed, surgical debridement, optimize HAART.
Open topicBone Grafts and Substitutes
Autograft is gold standard: osteogenic + osteoinductive + osteoconductive (iliac crest). Allograft provides scaffold (osteoconductive) ± growth factors; immune & disease transmission risks minimized by processing. Substitutes: calcium phosphates (HA/TCP), calcium sulfate, bioactive glass; mainly osteoconductive. Biologics: BMP‑2/7, PRP (controversial), bone marrow aspirate concentrate. Applications: nonunion, defects, spinal fusion; match graft biology to defect needs.
Open topicBone Tumor Biopsy Principles
Biopsy should be performed only by definitive surgical team at referral center. Types: core needle (preferred), incisional, excisional. Incision along surgical approach, longitudinal not transverse. Biopsy tract must be excised en bloc at definitive surgery. Complications: contamination, hematoma, infection, inadequate sample.
Open topicBone Tumor Imaging — Lodwick
Lodwick classification describes patterns of bone destruction on radiographs. Type I: geographic (IA sclerotic rim, IB sharp margin, IC ill-defined). Type II: moth-eaten destruction. Type III: permeative pattern. Helps differentiate benign vs malignant and plan biopsy/management.
Open topicBone Turnover Markers
Formation markers: bone‑specific ALP, osteocalcin, P1NP. Resorption markers: CTX (C‑telopeptide), NTX, TRAP‑5b. Uses: monitoring therapy in osteoporosis and metabolic bone disease, not for diagnosis alone. Preanalytic variability: diurnal variation (fasting morning samples), renal/hepatic function influences.
Open topicBoth Bone Forearm Fractures
Simultaneous fracture of radius and ulna compromises pronation-supination. Adults: ORIF with plating is gold standard; children: closed reduction & casting. Principle: restore length, alignment, rotation of both bones. Complications: malunion, nonunion, radioulnar synostosis.
Open topicBoutonnière & Swan Neck
Define Boutonnière & Swan Neck with common etiologies and pathoanatomy. List key classifications or staging systems used in exams. Clinical features and focused examination; special tests as applicable. Imaging: first‑line and advanced; measurements that change management. Nonoperative indications and protocols. Operative indications; approach and key steps. Implant/technique options with pros/cons. Complications and how to prevent/manage them. Rehabilitation milestones and outcome expectations....
Open topicBoutonniere Deformity
Flexion of PIP joint with hyperextension of DIP joint. Caused by central slip rupture of extensor tendon at PIP. Mechanism: forceful blow, RA, laceration. Clinical: inability to extend PIP; DIP hyperextends via lateral bands. Treatment: splinting PIP in extension 6 weeks; surgery for chronic cases.
Open topicBrachial Plexus — Roots, Trunks, Cords, Branches
Brachial plexus consists of Roots (C5–T1), Trunks (upper, middle, lower), Divisions (each trunk splits into anterior/posterior), Cords (lateral, posterior, medial), and terminal Branches (musculocutaneous, axillary, radial, median, ulnar). Anatomical course: roots emerge between scalene muscles; trunks in posterior triangle; divisions under clavicle; cords encircle axillary artery and give off named nerves (e.g. lateral cord → musculocutaneous). Key relationships: the long thoracic nerve (C5-7)...
Open topicBrodie Abscess — Features & Management
Subacute osteomyelitis presenting as a localized lytic lesion with sclerotic rim (usually metaphyseal). Typical organisms: Staphylococcus aureus; culture may be negative. Symptoms: localized pain, minimal systemic signs, often night pain relieved by NSAIDs. Imaging: X‑ray—lytic cavity with sclerotic margin; MRI—rim enhancement with surrounding edema. Management: Curettage ± bone graft, culture‑directed antibiotics.
Open topicBuckle (Torus) & Plastic Bowing — Paediatric Forearm Patterns
Buckle/Torus: Compression failure of cortex (metaphyseal) — stable; treat with short immobilization/splint. Plastic Bowing: Microfracture without discrete break; persistent deformity if not recognized and reduced. Greenstick: One cortex fails in tension, other intact — needs gentle completion or molding to correct alignment.
Open topicCalcaneal Fractures — Sanders & Essex-Lopresti
Sanders classification: based on CT coronal posterior facet fractures. Essex-Lopresti: tongue vs joint depression patterns. Operative indications: displacement >2 mm, malalignment, large fragment involvement. ORIF via extensile lateral or sinus tarsi approach; primary subtalar fusion in severe comminution. Complications: wound breakdown, infection, subtalar arthritis.
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