Orthopaedics

Orthopaedics is one of the most high-yield, high-return clinical subjects in NEET PG and INI-CET. It is image-rich, fact-dense, and beautifully suited to single-best-answer (SBA) MCQs because so much of the discipline is built on eponyms, classifications, fixed angles, radiographic signs and reproducible clinical tests. A focused candidate can convert almost every orthopaedics question into a correct mark — the subject rewards pattern recognition far more than reasoning, which makes it the single best "scoring per hour invested" clinical subject after the short-but-dense ones (Anaesthesia, Radiology, Skin).

This mother page maps the entire subject the way it is tested, walks through each system group, flags the traps that cost students marks, and ends with a revision roadmap, high-yield tables, mnemonics and rapid-fire one-liners.

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How Orthopaedics Is Tested

Weightage

In NEET PG, Orthopaedics typically contributes 8–12 questions (roughly 4–6% of the paper), and in INI-CET it tends to be slightly more concept-heavy with 5–8 questions that lean toward classifications, recent management shifts, and clinical photographs. PGMEE/state exams have historically loved trauma eponyms and paediatric ortho.

Although the absolute count is modest, the accuracy ceiling is very high — well-prepared students target near 100% in this subject because the recurring fact base is finite and repeats across years.

Question styles that recur

Style	What it looks like	Example trigger
Eponym recall	"Fracture of distal radius with dorsal angulation"	Colles
Classification staging	"Garden III femoral neck fracture management"	Staging → treatment
Clinical test	"Test for ACL integrity"	Lachman / anterior drawer
Radiographic sign	"Codman triangle, sunburst, lytic lesion in metaphysis of young patient"	Osteosarcoma
Image-based	X-ray / clinical photo of deformity	Identify lesion + next step
Best management/next step	"Most appropriate treatment of …"	Implant or procedure choice
Numerical value/angle	"Normal neck-shaft angle / acetabular index"	Fixed value recall
Single-line association	"Nightstick fracture = …"	Isolated ulna shaft

The most reliable theme: mechanism → fracture pattern → classification → complication → fixation choice. Master that chain and most trauma questions collapse into recall.

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Group 1: Trauma

Trauma is the largest and most consistently tested group. Expect 3–5 questions from this section alone.

Upper limb fractures — must-know associations

Fracture/eponym	Description	Classic association / complication
Colles	Distal radius, dorsal displacement, dinner-fork deformity	Common in elderly osteoporotic women; EPL rupture late
Smith	Distal radius, volar displacement (reverse Colles)	Garden spade deformity
Barton	Intra-articular distal radius with subluxation	Volar/dorsal Barton
Chauffeur (Hutchinson)	Radial styloid	Backfire injury
Galeazzi	Distal radius shaft + DRUJ dislocation	"MUGR" — Monteggia Ulna, Galeazzi Radius
Monteggia	Proximal ulna + radial head dislocation	PIN (posterior interosseous nerve) injury
Nightstick	Isolated ulnar shaft	Defensive injury
Scaphoid	Anatomical snuffbox tenderness	AVN of proximal pole (retrograde blood supply); risk of non-union
Supracondylar humerus (children)	Most common elbow fracture in kids	Brachial artery / median (AIN) injury; Volkmann ischaemic contracture; cubitus varus (gunstock) deformity late
Humeral shaft	Spiral fracture	Radial nerve palsy (wrist drop)
Surgical neck humerus	Elderly fall	Axillary nerve injury (regimental badge anaesthesia)
Clavicle	Junction of middle and outer third	Commonest site; conservative mgmt usually

Trap: Holstein–Lewis fracture = distal-third spiral humeral shaft fracture with radial nerve entrapment — students confuse "radial nerve injury site" — it is the distal third, not mid-shaft, that classically traps the nerve.

Lower limb fractures — high yield

• Femoral neck (intracapsular): Garden classification (I–IV). Young patient → urgent internal fixation (cannulated screws) to salvage the head; elderly displaced (Garden III/IV) → hemiarthroplasty / THR. Major complications: AVN of femoral head and non-union (poor retrograde blood supply via medial femoral circumflex / lateral epiphyseal vessels).
• Intertrochanteric (extracapsular): Older patients; DHS (dynamic hip screw) for stable, PFN/cephalomedullary nail for unstable/reverse oblique. AVN is rare here (extracapsular = good blood supply).
• Femoral shaft: Closed interlocking IM nail is gold standard. Watch for fat embolism and significant blood loss (1–1.5 L).
• Tibial shaft: Most common site of open fracture and compartment syndrome.
• Ankle: Weber A/B/C (relation to syndesmosis); Lauge-Hansen (mechanism). Maisonneuve = proximal fibula fracture + syndesmotic/ankle injury.

Compartment syndrome — guaranteed favourite

• Earliest and most reliable sign: pain out of proportion, especially pain on passive stretch.
• The "6 P's" (pain, pallor, paraesthesia, pulselessness, paralysis, poikilothermia) — pulselessness is a LATE sign; do not wait for it.
• Diagnosis confirmed by compartment pressure: absolute >30 mmHg, or delta pressure (diastolic BP − compartment pressure) < 30 mmHg is the more accepted criterion.
• Treatment: emergency fasciotomy.

Trap: Students pick "absent pulse" as the diagnostic sign. The diagnostic action is fasciotomy based on clinical suspicion and delta pressure — never delay for pulselessness.

Other trauma high-yield

• Fat embolism syndrome: long-bone/pelvic fractures, 24–72 h later, petechiae (axilla, conjunctiva), hypoxia, neurological signs. Gurd's criteria. Management is supportive (oxygenation, early fracture fixation as prevention).
• Open fractures: Gustilo–Anderson classification (I, II, IIIA/B/C). IIIC = arterial injury requiring repair. Early antibiotics + debridement.
• Pelvic fracture: open-book (APC) injury → haemorrhage; pelvic binder. Associated urethral/bladder injury.
• Salter-Harris (physeal) — see Paediatric Ortho.

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Group 2: Paediatric Orthopaedics

A reliably tested group with crisp, recallable facts. Expect 1–2 direct questions.

Salter–Harris classification (physeal injuries)

Mnemonic SALTR:

Type	Pattern	Mnemonic
I	Slipped (through physis)	S = Slip / Straight across
II	Above (metaphysis) — most common	A = Above
III	Lower (epiphysis, intra-articular)	L = Lower
IV	Through (both meta + epiphysis)	T = Through/Two
V	Crush (compression) — worst prognosis	R = Rammed/cRush

Type II is most common; Type V has worst prognosis (growth arrest, often missed initially).

Hip disorders by age (a perennial favourite)

Disorder	Typical age	Key facts
DDH (developmental dysplasia)	Newborn–infant	Ortolani (reduces) / Barlow (dislocates) tests; USG <6 months, X-ray after ossification; Pavlik harness <6 months
Perthes (avascular necrosis of femoral head)	4–8 yrs	Self-limiting AVN; "containment" treatment; boys; painless limp
SCFE (slipped capital femoral epiphysis)	Adolescent, obese	Trethowan's sign / Klein's line; in-situ screw fixation; hip pain may present as knee pain
Transient synovitis	3–8 yrs	Diagnosis of exclusion; post-viral; differentiate from septic arthritis (Kocher criteria)
Septic arthritis	Any	Emergency drainage; Kocher: fever, non-weight bearing, ESR >40, WBC >12,000

Trap: A limping adolescent with knee pain — always examine the hip (SCFE). This is a classic distractor.

Congenital / developmental conditions

• CTEV (clubfoot): components CAVE = Cavus, Adductus (forefoot), Varus (hindfoot), Equinus. Ponseti method (serial casting + percutaneous tenotomy) is the standard of care.
• Osteogenesis imperfecta: blue sclera, brittle bones, Type I collagen defect, dentinogenesis imperfecta; Sillence classification (Type II lethal).
• Achondroplasia: FGFR3 gain-of-function mutation; rhizomelic dwarfism; commonest cause of short-limb dwarfism; autosomal dominant.
• Genu varum/valgum: physiological varum <2 yrs, valgum 2–6 yrs; pathological → Blount disease, rickets.

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Group 3: Spine

Spine yields image-based and clinical questions — cord vs root signs, deformity, and the classic Pott's spine.

Disc prolapse and radiculopathy

Level	Root	Motor	Reflex	Sensory
L4–L5 disc	L5	EHL weakness, foot drop	—	Dorsum of foot, great toe web
L5–S1 disc	S1	Plantarflexion, weak push-off	Ankle jerk lost	Lateral foot, sole
L3–L4 disc	L4	Quadriceps	Knee jerk	Medial leg

• SLR (straight leg raise) positive in lower lumbar disc prolapse.
• Cauda equina syndrome = surgical emergency: saddle anaesthesia, bladder/bowel dysfunction, bilateral sciatica → urgent MRI + decompression.

Tuberculosis of spine (Pott's disease)

• Commonest site: lower thoracic / thoracolumbar (D11–L1).
• Starts in paradiscal region; disc space relatively preserved early (vs pyogenic which destroys disc early).
• Cold abscess, gibbus deformity, Pott's paraplegia.
• MRI is best imaging. Management: ATT (anti-tubercular therapy) is the mainstay; surgery for neurological deficit, instability, or large abscess. Hong Kong (anterior) procedure historically.

Other spine essentials

• Scoliosis: Cobb angle measures curve; adolescent idiopathic most common; brace 25–40°, surgery >45–50°.
• Spondylolisthesis: forward slip; Meyerding grading (I–IV by quartiles); pars defect (spondylolysis) in young athletes — "Scottie dog with collar" on oblique X-ray.
• Cervical spondylotic myelopathy: upper motor signs in limbs.
• Ankylosing spondylitis: HLA-B27, bamboo spine, sacroiliitis (overlap with medicine/rheumatology).

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Group 4: Bone Tumours

A high-yield, image-heavy group. The exam loves "age + location + radiographic sign → diagnosis."

Diagnostic triad table

Tumour	Age	Location	Classic radiographic sign
Osteosarcoma	10–20 yrs	Metaphysis (around knee — distal femur/proximal tibia)	Codman triangle, sunburst/sunray
Ewing sarcoma	5–15 yrs	Diaphysis of long bones	Onion-peel (lamellated) periosteal reaction; t(11;22), MIC2/CD99
Giant cell tumour (osteoclastoma)	20–40 yrs (after physeal closure)	Epiphysis/epi-metaphysis, around knee/distal radius	Soap-bubble, eccentric, lytic
Chondrosarcoma	>40 yrs	Pelvis, proximal femur	Popcorn/ring-stipple calcification
Osteochondroma (exostosis)	Adolescent	Metaphysis, away from joint	Most common benign bone tumour; cartilage-capped, points away from joint
Osteoid osteoma	Young	Cortex of long bones	Nidus with sclerosis; night pain relieved by NSAIDs/aspirin
Enchondroma	Any	Hands/feet (phalanges)	O-ring calcification; Ollier disease / Maffucci syndrome
Multiple myeloma	Elderly	Skull, axial	Punched-out lytic lesions, raised ESR, M-band
Metastasis	Elderly	Axial skeleton	Most common malignant bone "tumour" overall (esp. breast, prostate)

Key discriminators

• Most common benign bone tumour: Osteochondroma.
• Most common primary malignant bone tumour: Osteosarcoma (in young); multiple myeloma if counted among marrow tumours.
• Most common malignant bone lesion overall: Metastasis.
• GCT is locally aggressive, "benign but recurrent" — note it occurs after physeal closure (epiphyseal location).
• Blastic metastasis classically: prostate (and breast can be mixed).

Trap: Codman triangle is NOT pathognomonic of osteosarcoma alone — it reflects aggressive periosteal elevation and can occur in Ewing and infection. The full clinical picture (age, location) decides.

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Group 5: Infections

Acute osteomyelitis

• Commonest organism: Staphylococcus aureus (all ages).
• In sickle cell disease → Salmonella osteomyelitis (classic association).
• Neonates: Group B Strep, E. coli, S. aureus.
• Children: metaphysis of long bones (sluggish blood flow); haematogenous spread.
• Earliest investigation positive: MRI (sensitive early). X-ray changes lag 10–14 days (periosteal reaction, lytic changes). Bone scan also early.
• Sequestrum (dead bone), involucrum (new bone), cloaca, Brodie's abscess (subacute, walled-off).

Septic arthritis

• Emergency — joint destruction within days.
• S. aureus most common; gonococcus in sexually active young adults.
• Hip in children — urgent arthrotomy/drainage.
• Kocher criteria distinguish from transient synovitis (see Paediatric Ortho).

Tuberculous infection

• Spine most common skeletal site (Pott's); also hip and knee.
• "Caries sicca" (shoulder), cold abscess (no calor/rubor).

Trap: In a child with osteomyelitis, a "normal X-ray" does NOT exclude the diagnosis in the first week — order MRI; do not be reassured.

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Group 6: Arthroplasty & Degenerative Joint Disease

Osteoarthritis (OA)

• Primary degenerative; weight-bearing joints (knee, hip), DIP (Heberden nodes), PIP (Bouchard nodes).
• Radiographic tetrad: Loss of joint space (asymmetric), subchondral sclerosis, osteophytes, subchondral cysts.
• Management ladder: weight loss/physio → analgesia (paracetamol, NSAIDs) → intra-articular injections → joint replacement (TKR/THR) for end-stage.

Rheumatoid arthritis (overlap with Medicine)

• Symmetric, small joints (MCP, PIP — spares DIP), morning stiffness, ulnar deviation, swan-neck/boutonnière, atlantoaxial subluxation (anaesthetic concern).
• Radiology: juxta-articular osteopenia, marginal erosions, symmetric joint space loss.

Feature	OA	RA
Joints	DIP, weight-bearing	MCP/PIP, symmetric, spares DIP
Stiffness	Worse with activity, brief AM	Prolonged morning stiffness (>1 h)
X-ray	Osteophytes, sclerosis	Erosions, osteopenia
Nodes	Heberden/Bouchard	Rheumatoid nodules

Arthroplasty essentials

• THR/TKR for end-stage OA, AVN, displaced femoral neck fracture in elderly.
• Complications: infection (PJI), aseptic loosening, dislocation, DVT/PE, periprosthetic fracture.
• DVT prophylaxis is mandatory (LMWH / DOAC) — overlap with medicine.
• Avascular necrosis (AVN) of femoral head: causes by mnemonic ASEPTIC / steroids + alcohol lead the list; crescent sign on X-ray; MRI most sensitive; Ficat staging; treatment from core decompression (early) to THR (late/collapsed).

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Group 7: Metabolic Bone Disease

A bridge group with strong Medicine/Biochemistry overlap — frequently tested via lab-value patterns.

Biochemical pattern table (extremely high-yield)

Condition	Calcium	Phosphate	ALP	PTH	Key clue
Osteoporosis	Normal	Normal	Normal	Normal	T-score ≤ −2.5 (DEXA); fragility fracture
Osteomalacia / Rickets	↓/N	↓	↑	↑ (secondary)	Vit D deficiency; Looser zones (pseudofractures)
Primary hyperparathyroidism	↑	↓	↑	↑	"Stones, bones, groans, moans"; brown tumours; subperiosteal resorption
Renal osteodystrophy (secondary HPT)	↓	↑	↑	↑	CKD; "rugger jersey spine"
Paget disease	Normal	Normal	Markedly ↑	Normal	Bone pain, ↑ hat size, high-output cardiac failure; mosaic/woven bone
Osteopetrosis	N	N	N	N	Dense brittle bone; marble bone / Erlenmeyer flask / bone-in-bone; defective osteoclasts (carbonic anhydrase II)

Osteoporosis specifics

• DEXA T-score: Normal > −1; Osteopenia −1 to −2.5; Osteoporosis ≤ −2.5.
• Most common fracture sites: vertebra (most common), hip, distal radius (Colles).
• Bisphosphonates first-line; watch osteonecrosis of jaw and atypical subtrochanteric femoral fractures with long-term use.

Rickets / Osteomalacia

• Children = rickets (open physes): bow legs, rachitic rosary, widened wrists, Harrison sulcus.
• Adults = osteomalacia: Looser zones / pseudofractures (Milkman lines).
• Vitamin D deficiency most common cause; also X-linked hypophosphataemic rickets (phosphate wasting, normal calcium).

Trap: In osteoporosis, ALP and calcium are normal — a question giving "normal labs + fragility fracture in postmenopausal woman" is osteoporosis, NOT osteomalacia (which has raised ALP and low/normal calcium).

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Cross-Subject Integration Points

Orthopaedics overlaps richly with other subjects — examiners exploit these bridges.

Overlap subject	High-yield bridge topics
Anatomy	Nerve injuries with fractures (radial–humeral shaft, axillary–surgical neck, PIN–Monteggia, median/AIN–supracondylar); blood supply of femoral head & scaphoid (AVN logic); brachial plexus
Physiology/Biochem	Vitamin D & calcium metabolism, PTH axis, collagen types (Type I in OI, Type II cartilage)
Pathology	Bone tumour histology (osteosarcoma, Ewing CD99/t(11;22), GCT giant cells), AVN, gout (negatively birefringent urate crystals)
Medicine	RA, AS (HLA-B27), gout/pseudogout (CPPD positively birefringent), metabolic bone labs, DVT prophylaxis
Radiology	All the signs: Codman, onion-peel, soap-bubble, rugger jersey, Erlenmeyer flask, crescent sign
Surgery	Compartment syndrome, open fracture management, polytrauma/ATLS, fat embolism
Paediatrics	DDH, Perthes, SCFE, OI, achondroplasia, rickets
Microbiology	Osteomyelitis organisms (S. aureus, Salmonella in sickle cell), TB

A favourite integrated stem: a fracture site → which nerve → resulting deformity → physiological deficit. Knowing the nerve table converts an "anatomy" question into an easy mark.

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Recent Update Themes & Guideline Shifts

NEET PG and INI-CET increasingly reflect updated practice. Watch these:

• Open fracture antibiotics: Early IV antibiotics (within an hour) and timely debridement — the rigid "6-hour rule" is now nuanced toward early antibiotics + appropriate debridement timing rather than fixed cutoffs.
• Femoral neck fractures in physiologically young elderly: Growing preference for total hip replacement (THR) over hemiarthroplasty in active, independent elderly patients (better function, lower revision for acetabular wear).
• VTE prophylaxis after major lower-limb arthroplasty: DOACs increasingly favoured; mechanical + pharmacological combination.
• Ponseti method firmly established as standard for clubfoot over extensive surgical release.
• Periprosthetic joint infection (PJI): standardized diagnostic criteria (synovial WBC, alpha-defensin, culture) — concept-level recognition.
• Tranexamic acid (TXA) routine in arthroplasty/major trauma to reduce blood loss.
• Osteoporosis pharmacology: awareness of atypical femoral fractures and ONJ with prolonged bisphosphonates; denosumab and teriparatide in the algorithm.
• Damage control orthopaedics vs early total care in polytrauma (physiology-guided).

These "shift" topics are exactly where INI-CET likes to separate top scorers.

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Study Roadmap

First pass (build the skeleton)

1. Trauma first — it is the biggest yield. Memorise the eponym + nerve + complication table cold.
2. Bone tumours — pure pattern recognition (age + site + sign). High reward per hour.
3. Metabolic bone — learn the one lab table and you own the section.
4. Paediatric ortho — hip-by-age table + Salter-Harris + CTEV.
5. Spine, Infections, Arthroplasty — clinical correlation and management.

Consolidation

• Drill classifications (Garden, Gustilo, Salter-Harris, Weber, Meyerding) until automatic.
• Build a personal radiographic-sign deck (image → diagnosis). Examiners love photos.
• Solve previous-year PYQs topic-wise; ortho repeats heavily, so PYQ coverage approaches the question bank.

Last-week revision strategy

• Revise only tables and one-liners — do not open textbooks in the final week.
• Reread the nerve-injury table, lab-value table, tumour triad table, and hip-by-age table daily; these alone deliver most ortho marks.
• Skim your image/sign deck twice.
• Re-attempt wrong PYQs only.
• Memorise the fixed values/angles the night before (below).

Fixed values worth memorising

Parameter	Value
Neck-shaft angle of femur	~125° (120–135°)
Femoral anteversion	~15°
Acetabular index (newborn normal)	<30°
Tibiofemoral (physiological valgus)	~6°
Compartment syndrome delta pressure	< 30 mmHg
Osteoporosis T-score	≤ −2.5
Kocher criteria components	4 (fever, non-WB, ESR>40, WBC>12k)

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High-Yield Mnemonics

• CAVE — components of clubfoot: Cavus, Adductus, Varus, Equinus.
• SALTR — Salter-Harris I–V: Slip, Above, Lower, Through, Rammed (crush).
• 6 P's — compartment syndrome: Pain, Pallor, Paraesthesia, Pulselessness (late), Paralysis (late), Poikilothermia.
• "MUGR" — Monteggia = proximal Ulna; Galeazzi = distal Radius.
• Stones, Bones, Groans, Moans (+ psychic overtones) — hyperparathyroidism / hypercalcaemia.
• "Codman, Sunburst, Metaphysis, Young" — osteosarcoma snapshot.
• "Onion-peel + Diaphysis + CD99" — Ewing sarcoma.
• ASEPTIC (or recall Steroids + Alcohol) — leading causes of AVN femoral head.

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Rapid-Fire One-Liners

1. Commonest organism in osteomyelitis = Staphylococcus aureus; in sickle cell = Salmonella.
2. Scaphoid and femoral head share the trap of retrograde blood supply → AVN risk with proximal fractures.
3. Most common benign bone tumour = osteochondroma; most common malignant bone lesion overall = metastasis.
4. Earliest reliable sign of compartment syndrome = pain on passive stretch; pulselessness is late — never wait for it.
5. Radial nerve is injured in humeral shaft fracture (wrist drop); axillary nerve in surgical neck of humerus.
6. Monteggia fracture → posterior interosseous (PIN) injury; supracondylar humerus → brachial artery / AIN.
7. Garden III/IV femoral neck in elderly → arthroplasty; in young → urgent internal fixation to save the head.
8. Adolescent with knee pain and a limp → examine the hip (think SCFE) — Klein's line / Trethowan's sign.
9. Osteoporosis = normal calcium, phosphate and ALP; raised ALP points to osteomalacia/Paget instead.
10. Pott's spine starts paradiscal, spares disc early, commonest at thoracolumbar junction; ATT is the mainstay.
11. Ponseti method is standard of care for CTEV; Pavlik harness for DDH under 6 months.
12. GCT (osteoclastoma) is epiphyseal, occurs after physeal closure, soap-bubble appearance, locally aggressive and recurrent.