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O’Brien / Metaizeau — Paediatric Radial Neck Fractures
O’Brien Angulation: I (60°). Displacement/translation also matters; >3 mm or severe angulation predicts need for reduction/fixation. Metaizeau (elastic stable intramedullary nailing) classification is treatment-oriented with percutaneous leverage, intramedullary nail reduction, or open reduction for severely displaced injuries.
Open topicOpen Fractures — BOAST Principles
BOAST 4 guidelines: antibiotics ASAP, tetanus, debridement, stabilization, soft tissue cover. Do not remove bone fragments unless grossly non-viable. Definitive cover within 72 h (preferably 48). Stabilization with external fixator/IM nail/plate as appropriate. Complications: infection, nonunion, flap failure.
Open topicOrthopaedic Implants — Materials & Corrosion
Common alloys: 316L stainless, cobalt‑chrome, titanium (Ti‑6Al‑4V). Corrosion mechanisms: fretting at modular junctions, crevice under plates, galvanic with dissimilar metals. Clinical sequelae: metal ion release, ALVAL, osteolysis, trunnionosis in THA. Prevention: material pairing, surface finish, avoiding fluid‑filled crevices, firm taper assembly.
Open topicOrthoses — Lower Limb (KAFO/AFO)
AFO: ankle-foot support in drop foot, CP, polio. KAFO: supports knee in quadriceps paralysis, SCI. Types: rigid, hinged, leaf-spring (AFO); locked, drop lock, offset (KAFO). Goals: prevent deformity, support gait. Complications: sores, stiffness.
Open topicOsgood–Schlatter Disease
Apophysitis of tibial tubercle in adolescents due to repetitive traction from quadriceps. Common in athletic boys (10–15 yrs). Clinical: pain, swelling, prominent tender tibial tubercle. X-ray: fragmentation and irregularity of tibial tubercle apophysis. Treatment: activity modification, stretching, NSAIDs; resolves with skeletal maturity.
Open topicOsteochondral Autograft Transfer (OATS)
Cartilage repair technique for focal chondral defects
Open topicOsteochondral Defects — Autologous Chondrocyte Implantation (ACI)
Cartilage defects cause pain, swelling, mechanical symptoms; poor intrinsic healing. ACI: two-stage procedure — harvest cartilage → culture chondrocytes → reimplant under periosteal flap/biomatrix. Indications: symptomatic focal cartilage defects >2 cm² in young active patients. Alternatives: microfracture, OATS, osteochondral allograft. Complications: graft hypertrophy, delamination, failure.
Open topicOsteochondritis Dissecans (OCD)
Focal subchondral bone necrosis leading to cartilage instability. Common site: lateral aspect of medial femoral condyle. Clinical: pain, swelling, catching, locking in adolescents. Imaging: X-ray shows lucency; MRI defines stability of fragment. Treatment: stable juvenile lesions—activity modification; unstable/adult—drilling, fixation, grafting.
Open topicOsteogenesis Imperfecta — Sillence Types
OI due to COL1A1/2 defects; **Sillence I–IV** (classic) with expanded types V–VII; severity ranges from mild to perinatal lethal. Clinical: **blue sclerae**, dentinogenesis imperfecta, ligamentous laxity, short stature, recurrent fractures, hearing loss. Medical therapy: **bisphosphonates** (IV pamidronate/zoledronate) improve BMD and reduce fracture rate. Surgical: **intramedullary rodding** (telescopic Fassier–Duval) to correct deformity and reduce fractures. Multidisciplinary care: dental, au...
Open topicOsteoid Osteoma — Night Pain & RFA
Benign osteoblastic tumor
Open topicOsteolysis & Wear in Arthroplasty
Biologic response to wear particles (polyethylene > metal/cement) drives periprosthetic osteolysis via macrophage cytokine cascade. Risk factors: conventional PE, thin liners, malalignment, edge-loading, high activity, third-body wear. Radiology: progressive radiolucent lines, endosteal scalloping, cystic defects; CT helpful for pelvic osteolysis; metal artifact reduction MRI. Prevention: highly crosslinked PE (HXLPE), ceramic heads, proper component position, larger heads with caution for trunn...
Open topicOsteomalacia and Rickets
Defective mineralization: osteoid in adults (osteomalacia) vs physis in children (rickets). Etiologies: Vit D deficiency/resistance, phosphate deficiency (tumor‑induced, hereditary), renal tubular acidosis, CKD. Clinical: bone pain, proximal myopathy, waddling gait; in children—wrist/ankle widening, bowing, rachitic rosary, Harrison sulcus. Biochemical: Low Ca/PO4, High ALP, High PTH, Low 25‑OH Vit D (pattern varies in renal disease). Radiology: Looser’s zones; in rickets—widened physes with cup...
Open topicOsteomyelitis — Cierny–Mader Staging
Cierny–Mader classifies adult osteomyelitis by anatomic type (I–IV) and host status (A/B/C). Type I: Medullary; Type II: Superficial; Type III: Localized (cortical sequestration with stable bone); Type IV: Diffuse (circumferential). Host: A (healthy), B (systemic/local compromise), C (treatment worse than disease). Management tailored: debridement extent, stability, dead space management, local/systemic antibiotics. Principles: radical debridement, skeletal stability, soft-tissue cover, dead-spa...
Open topicOsteoporosis — Pathophysiology and Management
Definition (WHO): low bone mass with microarchitectural deterioration → fragility fractures; T‑score ≤ −2.5 on DEXA. Common sites: vertebral compression, hip (femoral neck/intertrochanteric), distal radius. Risk factors: age, female sex, postmenopausal status, low BMI, glucocorticoids, smoking/alcohol, endocrine/renal disease. Workup: DEXA (hip/spine), FRAX (10‑yr risk), labs to exclude secondary causes (Ca, PO4, ALP, 25‑OH Vit D, TSH, PTH, renal/liver). Treatment: lifestyle (Ca 1000–1200 mg; Vi...
Open topicOsteosarcoma — Diagnosis & Treatment
Most common primary malignant bone tumor in adolescents (after myeloma overall). Sites: metaphysis of long bones—distal femur, proximal tibia, proximal humerus. X‑ray: sunburst periosteal reaction, Codman triangle, mixed lytic–sclerotic lesion. Work‑up: MRI for local staging, CT chest for metastasis, bone scan for skip lesions. Treatment: neoadjuvant chemotherapy → wide resection/limb salvage/rotationplasty → adjuvant chemotherapy.
Open topicOsteosarcoma — Workup & Management
High‑grade intramedullary osteosarcoma affects metaphyses of long bones in adolescents (distal femur, proximal tibia, proximal humerus). Workup: **X‑rays**, **MRI with contrast** of entire bone, **CT chest**, and **bone scan/PET‑CT**; labs (ALP, LDH). Biopsy: **planned by treating team** along resection plane to avoid contaminating compartments. Standard treatment: **neoadjuvant chemotherapy (MAP)** → **wide resection** with limb‑salvage reconstruction where feasible → **adjuvant chemotherapy**....
Open topicOutpatient / Day-care Joint Replacement — Safety & Protocols
Enhanced recovery protocols (ERAS) enable same-day/next-day discharge in selected patients. Selection: ASA I–II, motivated, good support, no major comorbidities or bleeding risks. Protocol: multimodal anesthesia/analgesia, tranexamic acid, early mobilization, standardized discharge criteria. Benefits: lower cost, reduced infection risk, high satisfaction; challenges include safety in high-risk groups. Telemonitoring and home PT expand feasibility.
Open topicPaget’s Disease of Bone
Focal disorder of accelerated bone turnover: osteoclastic resorption followed by disorganized osteoblastic formation → enlarged, weak, vascular bone. Common sites: pelvis, spine, femur, tibia, skull; often polyostotic; usually age >55. Symptoms: bone pain, deformity (tibia/femur bowing), pathological fractures, skull enlargement, hearing loss; many asymptomatic. Labs: ↑ALP with normal Ca/PO4 (unless immobilization or hyperparathyroidism). Imaging: X‑ray with mixed lytic–sclerotic changes and bon...
Open topicPatella — Pattern-Based (AO/OTA 34)
Transverse, comminuted (stellate), polar avulsion, vertical; AO: 34-A extra-articular pole, 34-C transverse/comminuted. Displacement/extensor disruption → ORIF; minimal displacement → brace.
Open topicPatella Fractures — Tension Band Wiring
Indications: displaced transverse fractures with intact extensor. Principle: converts tensile quadriceps force into compression at fracture site. Technique: 2 parallel K-wires + figure-of-8 SS wire. Avoid in comminution → partial patellectomy/plate fixation. Complications: hardware prominence, migration, stiffness.
Open topicPatellar Dislocation — Acute
Most common acute dislocation of knee; lateral displacement of patella. Mechanism: valgus stress + external rotation with knee flexion. Clinical: sudden giving way, patella displaced laterally, hemarthrosis. Imaging: X-ray for osteochondral fracture; MRI for MPFL tear, loose bodies. Treatment: reduction + immobilization, physiotherapy; surgery if recurrent or osteochondral fracture.
Open topicPatellar Dislocation — MPFL
First‑time dislocation: non-op unless loose bodies/osteochondral fracture or gross instability. Recurrent instability → MPFL reconstruction; address bony factors (TT‑TG distance, trochlear dysplasia, patella alta). Imaging: MRI for MPFL injury/OC defects; CT to measure TT‑TG (>20 mm abnormal). Surgical pearls: Anatomic femoral tunnel at Schöttle point; avoid over‑tightening to prevent medial overload. Rehab: brace, early ROM, VMO strengthening; return to sport after strength and stability restor...
Open topicPatellar Instability — MPFL Reconstruction
Patellar instability often due to MPFL rupture after lateral patellar dislocation. Risk factors: trochlear dysplasia, patella alta, increased TT-TG distance. Clinical: recurrent dislocation, apprehension sign, medial tenderness. Imaging: MRI confirms MPFL injury, evaluates trochlear morphology; CT for TT-TG. Treatment: MPFL reconstruction using hamstring autograft; correct bony factors if severe.
Open topicPatellar Resurfacing in TKA — Controversies
Controversial: to resurface or not during TKA. Resurfacing: reduces anterior knee pain, avoids secondary resurfacing procedures. Non-resurfacing: avoids patellar complications (fracture, maltracking, loosening). Selective resurfacing based on patellar status increasingly practiced. Registry data show mixed outcomes; no universal consensus.
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