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MS ORTHOPAEDICS PAPER IV - HIGH-YIELD 10-MARK ANSWERS

Q1. AUTOLOGOUS CHONDROCYTE IMPLANTATION (ACI)

Introduction

Indications

• Full-thickness articular cartilage defects (Grade III-IV, Outerbridge)
• Defect size: 2-10 cm²
• Age: 15-55 years (active patients)
• Single contained lesion (femoral condyle, trochlea, patella)
• Failed prior cartilage repair procedures (microfracture)
• Normal or correctable limb alignment and meniscal status

Contraindications

• Osteoarthritis (diffuse cartilage loss)
• Inflammatory arthritis (RA)
• Uncorrected malalignment
• Defect > 10 cm²
• Uncorrected ligamentous instability

Technique - Three Generations

1. Stage 1 - Harvest: Arthroscopic biopsy of healthy cartilage (200-300 mg) from non-weight-bearing area (intercondylar notch or lateral trochlea)
2. Cell Culture: Chondrocytes isolated by collagenase digestion, expanded in culture medium for 3-5 weeks (12,000 cells → 12-48 million cells)
3. Stage 2 - Implantation (Open Surgery):
   • Debridement of defect to stable vertical walls, down to subchondral bone
   • Periosteal patch harvested from proximal medial tibia
   • Patch sutured to defect margins with fibrin glue seal
   • Chondrocyte suspension injected under the patch

• Periosteal patch replaced by type I/III collagen membrane (less hypertrophy)
• Marketed as MACI (Matrix-induced ACI) - cells seeded onto 3D collagen scaffold
• Implanted arthroscopically or via mini-arthrotomy with fibrin glue

• Chondrocytes grown on 3D biodegradable scaffolds (hyaluronic acid, fibrin, polyglycolic acid)
• Allows single-stage procedure (using juvenile allograft chondrocytes)

Rehabilitation Protocol

• Non-weight bearing for 6-8 weeks
• CPM commenced immediately post-op
• Partial weight-bearing at 8-12 weeks
• Return to sport at 12-18 months

Results

• 85-90% good to excellent results at 10 years (Brittberg)
• Produces hyaline-like cartilage (vs fibrocartilage in microfracture)
• Superior to microfracture for defects > 2 cm²

Complications

• Graft hypertrophy (periosteal - 20%; collagen - 5%)
• Delamination
• Failure of integration
• Knee stiffness
• Two-stage procedure is a disadvantage

Comparison: ACI vs Microfracture

Q2. MASQUELET TECHNIQUE (Induced Membrane Technique)

Introduction

Indications

• Large segmental bone defects (>5 cm) - post-traumatic, post-infective, post-tumour excision
• Failed conventional bone grafting
• Infected non-union with bone loss
• Congenital pseudarthrosis

Two-Stage Procedure

• Thorough debridement of all necrotic/infected bone and soft tissue
• Achievement of stable fixation (external fixator or nail)
• Filling the defect with a PMMA (polymethylmethacrylate) cement spacer
• Spacer may contain antibiotics (gentamicin, vancomycin) for infected cases
• Soft tissue closure over spacer
• Duration: 6-8 weeks (minimum) to 2-3 months

• Contains vascular endothelial cells, fibroblasts, osteoprogenitor cells
• Secretes angiogenic factors: VEGF, TGF-β1, BMP-2
• Has osteoinductive and osteoconductive properties
• Prevents resorption of bone graft (critical property)
• Acts as a biological chamber for bone regeneration

• Careful incision of induced membrane (preserve it!)
• Removal of cement spacer
• Filling the membrane tube with cancellous autograft (iliac crest) + RIA harvest
• Reamer-Irrigator-Aspirator (RIA) allows harvest of large volumes from femur/tibia
• Optional: add BMP-2, mesenchymal stem cells, PRF to augment
• Close membrane carefully over graft
• Maintain fixation until union

Results

• Union rates: 85-95% for defects 5-25 cm
• Mean time to union: 8-12 months
• Suitable for defects too large for conventional methods

Advantages

• Biological membrane acts as a "guided regeneration chamber"
• Can treat infected defects
• No need for vascularized fibula for defects up to ~20 cm
• Preserved periosteum and biology

Disadvantages

• Two-stage procedure
• Large volume of autograft required (donor site morbidity)
• Prolonged treatment time
• Technical demanding

Comparison with Ilizarov / Free Fibula

Q3. NANOTECHNOLOGY IN ORTHOPAEDICS

Definition

Applications in Orthopaedics

• Nanostructured hydroxyapatite (nano-HA) coatings on implants improve osseointegration (surface area 10× greater than conventional HA)
• Nano-titanium dioxide coatings with antibacterial properties
• Carbon nanotubes incorporated into polymer matrix improve mechanical strength of implants
• Nano-rough surfaces mimic natural bone architecture → better cell adhesion

• Nano-hydroxyapatite/collagen composites mimic natural bone (70% HA + 30% collagen at nano-level)
• Superior osteoconductive properties
• Bio-inspired scaffolds for bone tissue engineering (nano-HA + PLGA scaffolds)

• Nano-particles as drug carriers for targeted delivery
• Nanoliposomes for delivery of antibiotics (tobramycin, vancomycin) to biofilm in PJI
• PLGA nano-particles for controlled release of BMP-2, TGF-β (bone regeneration)
• Nano-carriers for anti-cancer drugs in bone tumours (targeted chemotherapy)
• Nano-silver particles: broad-spectrum antibacterial → implant coatings to prevent infection

• Nano-fibrous scaffolds (electrospun nanofibers) mimic collagen architecture of cartilage
• Nano-polymer scaffolds seeded with chondrocytes for cartilage tissue engineering
• Nano-composites as injectable scaffolds for cartilage defects

• Nano-coated pedicle screws for improved pullout strength in osteoporotic bone
• Nano-HA cement for vertebroplasty
• Nano-disc prostheses under development

• Nano-sensors for early detection of periprosthetic joint infection (PJI)
• Quantum dots for biomarker detection
• Nano-biosensors for real-time monitoring of implant integrity
• Gold nanoparticles in PCR-based rapid pathogen detection

• Nano-silver dressings for chronic wound care
• Nano-fibre wound dressings for degloving injuries

Challenges

• Long-term biocompatibility and toxicity of nanoparticles unknown
• Nano-particle accumulation in organs (liver, spleen, lung)
• High production cost
• Regulatory approval challenges
• Potential carcinogenicity

Future Directions

• Smart nano-implants with embedded sensors
• Nano-robots for targeted drug delivery
• Personalized nano-medicine in orthopaedics

Q4. OSTEOPOROSIS MANAGEMENT - RECENT ADVANCES

Definition

Assessment

• DEXA scan (gold standard): hip + lumbar spine
• FRAX tool (10-year fracture probability)
• Trabecular bone score (TBS)
• High-resolution peripheral QCT (HR-pQCT)

Management

• Calcium: 1000-1200 mg/day (dietary + supplements)
• Vitamin D: 800-2000 IU/day (target 25-OH Vit D > 30 ng/mL)
• Weight-bearing exercise, resistance training
• Fall prevention (home hazards, balance training)
• Lifestyle: stop smoking, limit alcohol

• Bisphosphonates: Alendronate (70 mg/week oral), Zoledronic acid (5 mg IV/year) - first line; inhibit osteoclast activity; drug holidays after 3-5 years (risk of atypical femur fractures and ONJ)
• Denosumab (Prolia): RANK-L inhibitor; 60 mg SC every 6 months; superior to bisphosphonates in renal impairment; rebound increase in bone turnover on cessation → must transition to bisphosphonate
• SERMs: Raloxifene - vertebral fractures only; risk of VTE

• Teriparatide (PTH 1-34): Daily SC injection; stimulates osteoblasts; 18-24 month course; reduces vertebral fractures by 65%, non-vertebral by 53%; followed by anti-resorptive
• Abaloparatide (PTHrP analogue): Similar to teriparatide; once daily SC
• Romosozumab (Evenity): Anti-sclerostin monoclonal antibody (dual action: anabolic + anti-resorptive); 210 mg SC monthly × 12 months; reduces vertebral fractures by 73%; risk of cardiovascular events (contraindicated in recent MI/stroke)

• Sequential therapy: Romosozumab → Denosumab → Bisphosphonate (maximum bone gain strategy)
• Odanacatib: Cathepsin K inhibitor (clinical trials)
• Setrusumab: Anti-sclerostin (osteogenesis imperfecta trials)

Orthopaedic Principles for Fragility Fractures

• Fix the fracture AND treat the underlying osteoporosis
• "Treat the bone, not just the fracture" - orthopaedic surgeon's role
• Fracture Liaison Services (FLS) - systematic identification and treatment
• Augmented fixation: cement augmentation, locked plating, nailing
• Vertebral fractures: vertebroplasty/kyphoplasty + medical treatment

Q5. 3D PRINTING IN ORTHOPAEDICS

Introduction

Technologies Used

• FDM (Fused Deposition Modelling): Thermoplastic polymers - models, guides
• SLS (Selective Laser Sintering): Nylon, PEEK - implants
• DMLS / SLM (Direct Metal Laser Sintering): Titanium, cobalt-chrome - load-bearing implants
• SLA (Stereolithography): Resin - anatomical models
• Bioprinting: Living cells in bioink scaffolds - tissue engineering

Applications in Orthopaedics

• 3D printed anatomical models from CT/MRI for complex cases (pelvis fractures, revision arthroplasty, deformity correction)
• Allows tactile understanding of complex anatomy
• Reduces operative time and improves surgeon confidence

• Custom cutting blocks and jigs for TKA/THA
• Improves accuracy of component positioning
• Reduces need for intraoperative navigation

• Pelvic reconstruction after tumour excision (custom hemipelvis)
• Spinal implants (custom cage for complex deformity)
• Custom acetabular cups for complex revision THA with large bone defects
• Mandibular/craniofacial reconstruction

• Preoperative planning with 3D tumour models
• Custom prostheses for limb salvage surgery
• Spacers and reconstruction implants after wide excision

• Custom interbody cages (PEEK or titanium with porous structure)
• Porous titanium cages: mimics trabecular bone architecture → better fusion
• Corrective osteotomy guides

• Complex periarticular fracture models for pre-bending plates
• Custom external fixator rings (Ilizarov)

• 3D bioprinting: cells + growth factors + scaffold printed simultaneously
• Chondrocyte-laden hydrogels for cartilage repair
• Osteoblast-laden scaffolds for bone regeneration (experimental)

• Surgical training models (simulated bones)
• Patient education tools

Materials Used

• Titanium alloy (Ti-6Al-4V): most common for implants
• PEEK (Polyetheretherketone): radiolucent, MRI compatible, modulus close to bone
• Cobalt-Chrome: bearing surfaces
• Bioceramics (HA, TCP): bone substitutes
• PLGA, PCL: biodegradable scaffolds

Advantages

• Perfect patient-specific fit
• Reduced operating time
• Porous structures promote osseointegration
• Complex geometries impossible with conventional manufacturing

Disadvantages/Limitations

• High cost, long production time (2-4 weeks)
• Regulatory hurdles (FDA approval for each custom device)
• Post-processing requirements
• Surface finish may require additional machining
• Fatigue properties of printed metal need validation

Q6. MDR-TB IN ORTHOPAEDICS

Definition

Diagnosis

• Cartridge-Based NAAT (CBNAAT/GeneXpert MTB/RIF): rapid (2 hours), detects MTB + rifampicin resistance
• Line Probe Assay (LPA): detects H + R resistance within 48 hours
• Culture + Drug Susceptibility Testing (DST): gold standard but 6-8 weeks
• Whole Genome Sequencing (WGS): comprehensive resistance profiling

WHO 2022 Treatment for MDR-TB (BPaL/BPaLC Regimen)

• BPaL regime: Bedaquiline (B) + Pretomanid (Pa) + Linezolid (L) - 6 months for highly susceptible MDR/XDR-TB
• BPaLC regime: Bedaquiline + Pretomanid + Linezolid + Clofazimine

• Group A (use all three): Levofloxacin/Moxifloxacin + Bedaquiline + Linezolid
• Group B (add if needed): Clofazimine, Cycloserine/Terizidone
• Group C (use if above insufficient): Ethambutol, Delamanid, Pyrazinamide, Imipenem-Cilastatin, Amikacin, Ethionamide, PAS

Orthopaedic Management of MDR Spinal TB

• Medical treatment as above (mandatory backbone)
• Surgery indications in spinal MDR-TB:
  • Neurological deficit (not improving or worsening)
  • Spinal instability / kyphosis > 60°
  • Large abscess causing cord compression
  • No response to 3-4 months of medical therapy
  • Diagnostic uncertainty
• Surgical principles: radical debridement (anterior approach), spinal cord decompression, fusion with autograft ± instrumentation
• Drug-eluting implants being investigated

MDR Osteoarticular TB (Other Sites)

• Hip: synovectomy, debridement; THR only after disease quiescence (2 years)
• Knee: arthroscopic synovectomy; arthrodesis if joint destroyed
• Same medical principles apply

Q7. STEM CELLS IN ORTHOPAEDICS

Types of Stem Cells

• Embryonic Stem Cells (ESCs): Pluripotent; ethical concerns
• Adult Mesenchymal Stem Cells (MSCs): Most clinically used; multipotent; found in bone marrow (BMAC), adipose tissue, periosteum, synovium
• Induced Pluripotent Stem Cells (iPSCs): Adult cells reprogrammed to pluripotency
• Haematopoietic Stem Cells (HSCs): For bone marrow transplantation

Sources for Orthopaedic Use

• Bone Marrow Aspirate Concentrate (BMAC) - posterior iliac crest
• Stromal Vascular Fraction (SVF) - adipose tissue (lipoaspirate)
• Periosteum, synovium, trabecular bone
• Umbilical cord blood (Wharton's jelly MSCs)

Differentiation Potential (MSCs)

• Osteogenic (bone)
• Chondrogenic (cartilage)
• Adipogenic (fat)
• Tenogenic, myogenic potential

Applications in Orthopaedics

• Core decompression + BMAC injection - most established use
• MSCs populate the necrotic zone + secrete angiogenic factors (VEGF)
• Best results in early stages (Steinberg I-III)
• BMAC + fibrin clot + structural support (tantalum rod)

• BMAC injection for early osteoarthritis (symptom relief + possible cartilage regeneration)
• MSC-seeded scaffolds for cartilage defect repair
• AMIC (Autologous Matrix-Induced Chondrogenesis): microfracture + collagen membrane + BMAC

• Percutaneous BMAC injection into non-union site
• MSCs + osteoinductive factors stimulate union

• MSCs + scaffold as bone graft substitute/expander
• Improved fusion rates in posterolateral fusion

• MSC injection into chronic tendinopathy (Achilles, patellar)
• Promotes tendon regeneration (not well-established)

• Nucleus pulposus stem cell injection: experimental
• Aim to reverse disc degeneration

Regulatory/Ethical Issues

• Minimal manipulation (BMAC, PRP) vs substantial manipulation (expanded MSCs)
• FDA/CDSCO approval required for culture-expanded products
• Avoid "stem cell tourism" - unproven claims

Q8. ROLE OF ARTIFICIAL INTELLIGENCE IN ORTHOPAEDICS

Definition

Applications

• Automated fracture detection on X-ray (AI-PAD, BoneView) - sensitivity 91%, specificity 95%
• Bone age assessment (GP Atlas replacement) - BoneXpert algorithm
• Osteoporosis screening from plain X-rays without DEXA
• Arthroplasty component wear measurement from serial X-rays
• Spinal deformity measurement (Cobb angle automation)
• MRI cartilage grading and OA severity scoring

• AI-based templating for THR/TKA (Blueprint, TraumaCad)
• Predicting optimal implant size and positioning
• 3D reconstruction from 2D X-rays

• Robotic surgery integration (Mako, ROSA) uses AI for real-time adjustments
• Image guidance with AI-driven registration
• Anomaly detection during surgery

• Predicting readmission, complications after TKA/THA
• Predicting non-union risk in fractures
• Identifying patients at risk for PJI
• Personalized rehabilitation protocols

• Automated clinical note generation
• Extracting data from medical records for research
• Surgical report summarization

• AI-driven drug discovery for osteoporosis, OA, bone tumours

Limitations

• "Black box" - lack of interpretability
• Bias in training data (predominantly Western populations)
• Regulatory approval (FDA clearance required)
• Data privacy concerns
• Not yet replacing clinical judgment

Q9. FRAGILITY FRACTURES - PRINCIPLES OF MANAGEMENT

Definition

Common Sites

• Vertebral compression fractures (most common - 50%)
• Distal radius (Colles fracture)
• Proximal femur (hip fracture - most morbid)
• Proximal humerus
• Ankle, pelvis (pubic rami)

Principles of Management

• Fix the fracture with augmented fixation (osteoporotic bone needs special attention)
• Proximal femur: cemented hemiarthroplasty/THA for displaced neck of femur; cephalomedullary nail for trochanteric fractures
• Distal radius: locked volar plate ± cement augmentation
• Proximal humerus: locked plates with augmented screws; consider hemiarthroplasty/RSA in very comminuted cases
• Vertebral: vertebroplasty/kyphoplasty for painful VCFs; instrumented fusion for instability/neurological deficit

• DEXA scan for all fragility fracture patients
• Fracture Liaison Services (FLS) model - coordinator-based systematic approach
• Start pharmacological treatment (bisphosphonate/denosumab/romosozumab)
• Calcium + Vitamin D supplementation

• Multifactorial fall assessment
• Home hazard modification
• Balance and strengthening exercises (Otago programme)
• Vision correction, medication review (stop CNS depressants)
• Hip protectors

Recent Trends

• Imminent fracture risk concept: Second fracture within 2 years at highest risk → "Hot Spot" clinics, immediate anti-osteoporotic treatment post-fracture
• Romosozumab: Anabolic-first strategy for severe osteoporosis
• Zoledronic acid given in hospital after hip fracture surgery
• ORIF + teriparatide: Concurrent treatment improves fracture healing
• Orthogeriatric co-management: "Blue Book" model reduces mortality
• Cement augmentation of pedicle screws, locking plates in poor bone

Q10. ROLE OF NAVIGATION IN TOTAL KNEE ARTHROPLASTY

Introduction

Types of Navigation Systems

• Image-based: Pre-op CT/MRI based planning (hip-knee-ankle axis calculated preoperatively)
• Imageless: Intraoperative kinematic registration only (most widely used); no preop imaging needed
• Accelerometer-based (portable navigation): Handheld sensors (KneeAlign, iAssist); low cost, no optical trackers

Technical Steps

1. Reference arrays fixed to femur and tibia (bicortical pins)
2. Registration: hip centre by pivoting femur; knee and ankle joint centre by digitization
3. Real-time display of: varus/valgus alignment, flexion/extension, tibial slope
4. Guided bone cuts with tracked cutting block
5. Gap balancing and trial assessment with navigated instruments
6. Final verification before cementing

Advantages

• Reduces outliers in component alignment (>3° from neutral) by 50%
• Useful in deformed anatomy (extra-articular deformity, previous long bone fracture)
• No intramedullary entry → reduces fat embolism risk
• Allows real-time kinematic assessment

Navigation in Fixed Flexion + Valgus Deformity

• Check posterior capsule contracture - posterior capsular release (pie-crusting)
• Additional distal femoral resection (1 mm bone = 1° flexion)
• Correct flexion gap: ensure equal flexion and extension gaps
• Navigation shows real-time extension gap
• Avoid excessive proximal tibial slope

• Navigation guides accurate bone cuts despite deformed anatomy
• Lateral soft tissue release guided by navigation feedback
• Steps: posterolateral capsule → popliteus → IT band (pie-crust) → lateral collateral ligament (rare)
• Navigation confirms correction of mechanical axis after each release
• May need constrained implant (PS or constrained condylar) if residual instability

Limitations of Navigation

• Increased operative time (15-20 minutes)
• Pin-site complications (fracture, infection)
• Learning curve
• Higher cost (optical navigation)
• Does not improve clinical outcomes significantly (comparable patient-reported outcomes to conventional TKA in meta-analyses)

Exam Tip: For a 10-mark question, aim for: Introduction (1 mark) + Classification/Types (2 marks) + Technique/Steps (3 marks) + Results/Advantages/Disadvantages (2 marks) + Recent Advances/Complications (2 marks). Use tables and diagrams where possible. Write in structured paragraphs with subheadings.Above are comprehensive 10-mark university exam answers for the 10 most repeated questions from your MS Orthopaedics Paper IV compiled list. Here's a quick summary of what's covered:

GROUP 2 ANSWERS

Q. XENOTRANSPLANTATION IN ORTHOPAEDIC SURGERY

Definition

Rationale / Need

• Shortage of human allografts
• Avoidance of donor site morbidity (vs autograft)
• Unlimited supply potential
• Useful in large defect reconstruction, revision surgery, tumour reconstruction

Types of Xenografts Used in Orthopaedics

• Bovine (Kiel bone, Lubboc bone) and porcine cancellous bone
• Deproteinized bovine bone mineral (Bio-Oss) - used in small defects
• Processed to remove cellular/protein components (reduce antigenicity)
• Osteoconductive scaffold only (not osteoinductive)
• Limited clinical use due to immune rejection

• Porcine cartilage (avascular - less immunogenic)
• Porcine-derived collagen scaffolds (OrthoADAPT)
• Porcine small intestinal submucosa (SIS) for cartilage repair
• Experimental decellularized osteochondral plugs from pigs

• Porcine derived processed tendons
• Bovine collagen tape for rotator cuff augmentation (Artelon, TissueMend)
• Porcine SIS patches for rotator cuff repair augmentation

• Experimental: porcine knee joint transplant into primates
• Genetically modified pigs (knockout of alpha-1,3-galactosyltransferase - Gal epitope) to reduce hyperacute rejection
• CRISPR-modified pigs (multiple gene knockouts + human transgene insertions)

Immunological Barriers

1. Hyperacute rejection (minutes-hours): Pre-formed anti-Gal antibodies activate complement → vascular endothelium destruction. Prevented by Gal-knockout pigs.
2. Acute vascular rejection (days): T-cell mediated + antibody
3. Chronic rejection (months): Ongoing immune activation

• Decellularization: removes immunogenic cellular components
• Genetic modification of donor animals (triple knockout pigs)
• Immunosuppression (limited use in non-vital grafts)
• Encapsulation technology (barrier membranes)
• Tolerance induction protocols (experimental)

Current Clinical Applications

• Decellularized porcine dermal collagen matrices (rotator cuff patches)
• Bovine pericardium patches
• Deproteinized bovine bone granules (dental/small orthopaedic defects)
• Collagen-based scaffolds derived from porcine or bovine sources

Zoonotic Risk

• Porcine endogenous retroviruses (PERVs) - integrated into pig genome
• Can potentially infect human cells in vitro
• CRISPR used to inactivate all 62 PERV copies in pig genome (Egenesis, 2017)
• Regulatory scrutiny: FDA guidance on xenotransplantation safety

Future Directions

• Genetically engineered pigs as universal donors
• Bioengineered xenografts with human ECM proteins
• 3D bioprinted xenograft scaffolds
• Whole knee joint xenotransplantation (long-term goal)

Q. CRYOTHERAPY IN ORTHOPAEDICS

Definition

Mechanisms of Action

• Vasoconstriction → reduced oedema and haemorrhage
• Decreased nerve conduction velocity → analgesia
• Reduced metabolic rate → decreased cellular demand
• Reduced muscle spasm
• At surgical temperatures (-20°C to -196°C): intracellular ice crystal formation → cell membrane disruption → cell death

PART A: THERAPEUTIC CRYOTHERAPY (Rehabilitation/Post-op)

• Ice packs / crushed ice (0-4°C)
• Cold compression devices (Cryocuff, Game Ready): combines cold + intermittent compression
• Whole body cryotherapy (WBC): -110°C to -140°C chambers (sports recovery)

• Post-operative swelling/pain (TKA, shoulder surgery, arthroscopy)
• Acute sports injuries (RICE protocol)
• Muscle spasm, tendinitis
• Post-exercise recovery in athletes

• Cold compression devices reduce post-TKA swelling and opioid consumption
• Whole body cryotherapy used by elite athletes for recovery

PART B: SURGICAL CRYOTHERAPY (Cryosurgery / Cryoablation)

• Liquid nitrogen (-196°C): most powerful, used for aggressive lesions
• Argon gas (-185°C): cryoprobe systems (percutaneous)
• Liquid CO2 (-79°C): less powerful, historical use

1. Direct: Ice crystal formation → cell membrane rupture
2. Indirect: Ischaemia from microvascular damage
3. Immune: Cryoimmunology - cryo-ablation releases tumour antigens → immune response

• Rapid freeze to -40°C (lethal zone) → slow thaw → rapid refreeze
• Two cycles recommended for complete tumour kill

1. Benign aggressive bone tumours:
   • Giant cell tumour (GCT) of bone - most common use
   • Aneurysmal bone cyst (ABC)
   • Chondroblastoma
   • Fibrous dysplasia
2. Low-grade malignant bone tumours (palliative/adjuvant)
3. Metastatic bone lesions (percutaneous cryoablation for pain control)
4. Soft tissue tumours (desmoid, aggressive fibromatosis)
5. Osteoid osteoma (CT-guided percutaneous radiofrequency ablation or cryoablation)

• Wide excision of tumour + curettage
• Extended curettage (high-speed burr)
• Liquid nitrogen poured into cavity (2-3 freeze-thaw cycles)
• Cavity reconstruction: bone cement (PMMA) + internal fixation
• PMMA acts as an additional chemical adjuvant (exothermic reaction)

• Joint-preserving surgery possible
• Reduced local recurrence vs curettage alone
• Lower morbidity than wide resection
• GCT: recurrence 15-20% vs 40-50% with curettage alone

• Fracture (thermal weakening of bone)
• Skin/soft tissue necrosis
• Nerve damage (cryoneuropraxia)
• Joint stiffness
• Wound healing problems
• Gas embolism (liquid nitrogen vapour)

Q. RADIATION HAZARDS IN ORTHOPAEDICS & PREVENTIVE MEASURES

Sources of Radiation in Orthopaedics

• C-arm fluoroscopy (most common): fracture fixation, arthroplasty, spine surgery
• Plain X-rays (pre/post-op)
• CT scans (planning)
• Intraoperative CT (O-arm)
• Radiation therapy (bone tumours)
• PET-CT, bone scans

Types of Radiation Exposure

• Ionizing radiation: X-rays, gamma rays - cause DNA damage
• Direct exposure: primary beam
• Scatter radiation: most significant risk for surgeons (80-90% of occupational exposure)
• Scatter decreases with inverse square of distance

Biological Effects

• Skin erythema, burns (acute, high dose)
• Cataracts (lens dose > 0.5 Gy cumulative)
• Radiation dermatitis of hands (long fluoroscopy procedures)

• Malignancy: leukaemia, thyroid cancer, breast cancer, brain tumours
• Genetic mutations (germline)
• Risk increases proportionally with cumulative dose

Units and Limits

• Whole body: 20 mSv/year (averaged over 5 years), max 50 mSv in any single year
• Extremities (hands): 500 mSv/year
• Lens of eye: 20 mSv/year
• Pregnant staff: 1 mSv to foetus during pregnancy

Preventive Measures (ALARA Principle)

• Use short pulses, intermittent screening
• Avoid continuous screening
• Last image hold function

• Stand as far from X-ray source as possible
• Ideally > 2 metres during exposure

• Lead apron (0.25-0.5 mm Pb equivalent): reduces scatter by 90-95%
• Lead thyroid collar: thyroid 20× more sensitive
• Lead-lined gloves (for hands in primary beam)
• Lead goggles/glasses (cataract prevention)
• Lead glass screens/curtains in OT
• Protective drapes over patient's abdomen/gonads

• Collimate beam to region of interest (reduces scatter volume)
• Use lowest possible mA and kV settings
• Position image intensifier close to patient (reduce magnification, reduce dose)
• Use pulse fluoroscopy (1-4 pulses/sec) vs continuous
• Digital systems (lower dose than film)

• TLD (Thermoluminescent Dosimeter) badge - worn outside lead apron at collar level
• Ring dosimeter for hands
• Regular dose monitoring reports

• C-arm: source below the table (reduces scatter to surgeon's head/eyes)
• Surgeon on image intensifier side (not X-ray tube side)
• Use lateral position (tube away from surgeon)

• Computer navigation (reduces fluoroscopy time by 60%)
• Robotic surgery
• Ultrasound guidance where possible
• Electromagnetic navigation (no radiation)

• Dose registers, annual review
• Radiation safety officer
• Pregnant staff: reassignment/restrictions
• Training and awareness

Orthopaedic Surgeon's Cumulative Risk

• Spine surgeons: highest exposure
• Trauma surgeons: second highest
• Studies show elevated rates of cataracts, left-side tumours in orthopaedic surgeons

Q. ALL-INSIDE TECHNIQUE FOR MENISCAL REPAIR

Introduction

Anatomy Relevant to Repair

• Outer 25-30% of meniscus is vascular (red-red zone) - best healing
• Middle 25% (red-white zone) - variable healing
• Inner 50% (white-white zone) - avascular, poor healing
• All-inside repair typically used for posterior horn tears

Indications for Meniscal Repair (General)

• Vertical longitudinal tears in vascular zone (red-red, red-white)
• Tear length > 1 cm
• Age < 40 years, stable knee
• Acute tears (< 8 weeks) - better healing
• Concomitant ACL reconstruction (enhances healing via haemarthrosis)

All-Inside Technique

• FasT-Fix (Smith & Nephew): suture-based, two polyethylene anchors connected by suture
• RapidLoc (DePuy Mitek): suture anchor + backstop
• OMNISPAN (DePuy Mitek): flexible dart-type device
• Meniscal Cinch (Arthrex): self-capturing suture passer
• MaxFire (Biomet): similar principle

1. Diagnostic arthroscopy - assess tear pattern, zone, stability
2. Tear preparation: shave/rasp tear surfaces to create bleeding (fibrovascular response)
3. Portal placement: standard anterolateral and anteromedial portals
4. Device insertion: loaded needle passed through meniscal tear into capsule
5. First anchor deployed in capsule/outer meniscal periphery (toggle/backstop mechanism)
6. Needle withdrawn 5-6 mm, second anchor deployed across tear
7. Suture pulled → slides both anchors together → compresses tear
8. Knot tied (pre-tied or manual) → sets suture tension
9. Suture trimmed
10. 2-3 devices per cm of tear (vertical mattress configuration preferred)

• Vertical mattress: captures most meniscal fibres (circumferential fibres) - stronger
• Horizontal: easier but weaker

Advantages of All-Inside Technique

• Fully arthroscopic - no additional incisions
• Reduced neurovascular risk (no risk to saphenous or common peroneal nerve)
• Faster operating time
• No need to reposition patient
• Good access to posterior horn (best indication)
• Equal biomechanical strength to inside-out in recent studies
• Applicable to complex/radial tears with newer generation devices

Disadvantages of All-Inside Technique

• Cost: Implant devices expensive (vs suture-only inside-out)
• Device prominence/irritation - implant can migrate or cause synovitis
• Implant failure: suture breakage, anchor pullout
• Less versatile for mid-body tears (inside-out preferred)
• Cannot be used for anterior horn tears
• Learning curve required
• Biological healing still depends on vascular zone placement
• Some devices may not achieve ideal suture orientation

Comparison of Meniscal Repair Techniques

Rehabilitation Post-Repair

• Weight bearing: 6 weeks partial then full (isolated repair)
• No deep flexion for 6 weeks
• Return to sport: 4-6 months
• Healing rate: 70-90% (red-red zone), 50-70% (red-white zone)

Q. THR VERSION: TECHNICAL STEPS, COMBINED ANTEVERSION, MODIFICATION FOR SPINAL DEFORMITY

Introduction

Target Zones

• Inclination (abduction): 40° ± 10°
• Anteversion: 15° ± 10°
• Limitations: does not account for functional position or spinal alignment

PART A: TECHNICAL STEPS FOR ACETABULAR CUP VERSION

1. Patient positioning: strict lateral decubitus, pelvis perpendicular to floor (neutral pelvic tilt)
2. Verification of pelvis orientation: palpate ASIS bilaterally, ensure symmetry
3. Use of mechanical alignment guide: set to 40-45° inclination, 15-20° anteversion
4. Fluoroscopic or navigation verification intraoperatively
5. Cup impacted confirming orientation with reference to acetabular anatomical landmarks:
   • Cup rim parallel to transverse acetabular ligament (TAL) - reliable landmark for anteversion (TAL method - Archbold)
   • TAL = horizontal reference → cup opening parallels TAL
6. Final verification: trial reduction + impingement/dislocation test in flexion-adduction-IR

• Transverse Acetabular Ligament (TAL): most reliable intraoperative guide
• Anterior wall of acetabulum
• Pelvic reference (ASIS, pubic symphysis)

PART B: TECHNICAL STEPS FOR FEMORAL STEM VERSION

1. After broaching/rasping femoral canal to correct size
2. Version assessed with: trial stem in place, knee flexed to 90°
3. Anteversion measured as angle between femoral neck axis and knee axis (transcondylar axis)
4. Normal: 10-15° anteversion
5. For cementless stems: version largely determined by proximal metaphyseal geometry and stem design (fixed anteversion stems vs adjustable)
6. For cemented stems: version can be set freely during cementing (knee flexed 90°, set ante/retroversion before cement sets)
7. Modular stems (S-ROM, Wagner): proximal body rotation independent of distal stem

Combined Anteversion

• < 25°: posterior instability risk

• 50°: anterior instability risk

• Combined anteversion compensates for individual component variation
• A cup with 5° anteversion is acceptable if stem has 30° anteversion (combined = 35°)
• Navigation and robotic systems calculate combined anteversion in real time

PART C: MODIFICATION FOR FIXED LUMBAR LORDOSIS / FLAT BACK

• Standing: pelvis tilts anteriorly (with lumbar lordosis) → increases functional cup anteversion
• Sitting: pelvis tilts posteriorly → decreases functional cup anteversion
• Stiff lumbar spine cannot compensate → fixed pelvic tilt

• Normal spine: flexes on sitting → posterior pelvic tilt compensates → cup opens anteriorly
• Stiff spine: cannot flex → pelvis stays in fixed tilt in all positions

• Pelvis permanently anteriorly tilted
• Functional cup anteversion is REDUCED (cup faces down/posterior)
• Anterior instability risk reduced, posterior instability risk INCREASED
• Modification: INCREASE acetabular anteversion by 5-10° compared to standard
• Consider posterior soft tissue repair/capsular repair
• Target CA shifted to higher end (40-50°)

• Pelvis permanently posteriorly tilted (retroversion in standing)
• Functional cup anteversion is INCREASED (cup faces anteriorly more)
• Anterior dislocation risk in extension
• Modification: DECREASE acetabular anteversion by 5-10°
• May need constrained liner if severe
• Target CA shifted to lower end (25-35°)

• Flat back → Reduce anteversion (or cup faces too anteriorly)
• Hyperlordosis → Increase anteversion (cup faces too posteriorly)

• EOS full-body imaging: assesses spinopelvic parameters (PI, PT, SS, lumbar lordosis)
• CT-based planning: measures true cup/stem anteversion
• Functional CT in standing/sitting: shows pelvic tilt variation
• Pelvic incidence (PI) - fixed anatomical parameter
• Pelvic tilt (PT), Sacral slope (SS) - positional parameters

Q. MINIMALLY INVASIVE SPINAL SURGERIES (MISS)

Definition

Rationale

• Muscle ischaemia, denervation, atrophy
• Post-laminectomy syndrome, failed back surgery syndrome
• MISS reduces: blood loss, infection, hospital stay, return to activity

Classification of MISS Techniques

• Percutaneous pedicle screw fixation
• Vertebroplasty / Kyphoplasty
• Sacroiliac joint fusion
• Disc nucleoplasty / annuloplasty

• Microdiscectomy (Caspar, MED - Microendoscopic Discectomy)
• Tubular decompression for spinal stenosis
• Working channel: 16-22 mm diameter
• Magerl/McCulloch minimicrodiscectomy concept

• Uniportal Full Endoscopic Discectomy (FED) - interlaminar or transforaminal
• Biportal Endoscopic Spine Surgery (BESS)
• Percutaneous Endoscopic Lumbar Discectomy (PELD)
• Working channel endoscope with continuous saline irrigation

• XLIF (eXtreme Lateral Interbody Fusion) / DLIF
• Oblique Lateral Interbody Fusion (OLIF)
• Access via retroperitoneal corridor without entering peritoneum
• Neuromonitoring essential (lumbar plexus at risk)

• Mini-ALIF (Anterior Lumbar Interbody Fusion)
• TLIF (Transforaminal LIF) - most common posterior minimally invasive fusion

• Unilateral or bilateral tubular retractor (22-26 mm)
• Ipsilateral facetectomy, discectomy, PEEK cage insertion
• Percutaneous pedicle screws contralaterally
• Single- or two-level fusion
• Indications: spondylolisthesis, degenerative disc disease, recurrent disc herniation

Specific Procedures

• Sequential dilators over guide wire, 18 mm tubular retractor
• Endoscope-assisted discectomy
• Day-case procedure, equivalent outcomes to open microdiscectomy

• Percutaneous balloon tamp inflated in vertebral body → creates cavity → restore height
• Fill with bone cement (PMMA) under low pressure
• Indications: painful osteoporotic VCF, osteolytic metastases
• Reduces cement leak risk vs vertebroplasty

• Jamshidi needle into pedicle, Kirschner wire, sequential dilators, screw over wire
• Connected by percutaneous rods through stab incisions
• Used for: trauma (thoracolumbar burst fractures), minimally invasive fusion

Advantages of MISS

• Reduced blood loss (50-80% less)
• Reduced post-operative pain (less muscle damage)
• Shorter hospital stay (1-2 days vs 4-5)
• Faster return to activity
• Lower infection rate
• Equivalent fusion rates to open surgery

Disadvantages

• Steeper learning curve
• Higher radiation exposure (fluoroscopy dependent)
• Limited visualisation - technical difficulty
• Higher equipment cost
• Cannot address all pathologies (severe deformity, trauma with instability)
• Longer operative time initially

Q. STOPPA'S APPROACH (MODIFIED STOPPA / PELVIC BRIM APPROACH)

Introduction

Indications

• Acetabular fractures involving:
  • Anterior column fractures
  • Anterior wall fractures
  • Both column fractures
  • Transverse + posterior wall
  • T-type fractures
  • Associated anterior + posterior hemitransverse
• Acetabular revision surgery (anterior column defects)
• Pelvic ring injuries (pubic symphysis, anterior ring)
• Pelvic tumour excision (anterior pelvis)

Anatomy

• Rectus abdominis (medial, retracted)
• Iliac vessels: external iliac artery and vein (lateral, protected)
• Obturator vessels and nerve (anterolateral border of quadrilateral surface - must protect)
• Vas deferens / round ligament of uterus
• Corona mortis (aberrant obturator artery from external iliac - present in 15-30%, must ligate)
• Quadrilateral surface of acetabulum (entire surface visible)

Surgical Steps

1. Patient position: Supine on radiolucent table
2. Incision: Pfannenstiel (transverse) or lower midline, 2-3 cm above pubic symphysis
3. Develop space of Retzius: Blunt dissection behind pubic symphysis (extraperitoneal)
4. Rectus abdominis: Divided or retracted medially
5. Peritoneum: Retracted superiorly (extraperitoneal approach)
6. Iliac vessels: Identified, protected with malleable retractors
7. Corona mortis: Identified and ligated (important step)
8. Obturator nerve and vessels: Protected along pelvic brim
9. Quadrilateral surface: Directly visualized and accessed
10. Reduction: Reduction clamps applied to pelvic brim; quadrilateral surface elevated
11. Fixation: Infrapectineal plate along pectineal eminence, buttress plate on quadrilateral surface, pelvic brim plate

Key Anatomical Landmark: Corona Mortis

• Anastomosis between obturator artery/vein and external iliac/inferior epigastric
• Present in 15-30% of patients
• Lies 4-6 cm from pubic symphysis
• If not identified and controlled: catastrophic haemorrhage
• Must be ligated as a routine step

Advantages Over Ilioinguinal Approach

• Single window vs three windows (ilioinguinal)
• No dissection of inguinal canal structures
• Better direct access to quadrilateral surface
• Quicker to perform, less complex
• Can be combined with Kocher-Langenbeck (combined approaches)
• Reduced risk to lateral femoral cutaneous nerve

Disadvantages

• Cannot access posterior column directly
• Limited access to anterior iliac wing (need to add lateral window for iliac crest fractures)
• Risk to obturator nerve if inadequate exposure
• Risk to bladder
• Not suitable for anterior wall fractures with superior dome involvement alone

Extensile Modifications

• Pararectus approach: More lateral incision, provides wider iliac window
• Combined Stoppa + ilioinguinal lateral window: Most anterior column fractures
• Combined Stoppa + Kocher-Langenbeck: Both column fractures with displaced posterior column

Q. MOTORIZED INTRAMEDULLARY BONE LENGTHENING IN ADULTS (PRECICE NAIL)

Introduction

Principle

Types of Motorized IMN Systems

• PRECICE 2/PRECICE STRYDE (NuVasive): Femur and tibia; most widely used
• FITBONE (Wittenstein): Fully implantable with transcutaneous electrical actuation
• ISKD (Intramedullary Skeletal Kinetic Distractor): Step-controlled (historical, no longer used)
• BLESS (Bone Lengthening with an Electronic System): Newer generation

Indications

• Limb length discrepancy (LLD) > 2 cm in adults (physiological lengthening complete)
• Post-traumatic LLD
• Post-infective LLD (after osteomyelitis)
• Congenital short femur / tibial hemimelia (after maturity)
• Achondroplasia/hypochondroplasia (stature lengthening)
• Short stature correction (controversial, cosmetic indication)
• Fracture non-union with shortening

Contraindications

• Active infection
• Open physis (relative - concern about physeal damage)
• Inadequate bone stock
• Severe deformity requiring concurrent correction (better with external fixator)
• Patient non-compliance (cannot operate the external controller)

Principles of Distraction Osteogenesis (Ilizarov)

1. Corticotomy/Osteotomy: Low-energy bone cut (preserves endosteum and periosteum)
2. Latency period: 5-7 days post-osteotomy before distraction (soft callus forms)
3. Distraction rate: 1 mm/day
4. Distraction rhythm: 0.25 mm × 4 times/day (original Ilizarov) or 0.1 mm multiple times (motorized allows continuous micro-distraction)
5. Consolidation: 1 month/cm lengthened (healing index: 1 day/mm)
6. Neutral fibrous interzone: Active new bone formation in zone of distraction

Surgical Steps (PRECICE Femoral Nail)

1. Preoperative planning: template nail length, diameter, starting point
2. Standard IMN entry point (piriformis or trochanteric)
3. Canal reaming
4. Osteotomy: percutaneous, low-energy (Gigli saw or drill-and-complete)
5. Nail insertion with distal locking screws (first)
6. Proximal locking screws
7. Post-op: activation with ERC after latency of 5-7 days; 1 mm/day distraction

Advantages

• No external frame: dramatically improved comfort and compliance
• No pin site infections (major advantage over Ilizarov/monorail)
• Normal body image / psychosocial benefits
• No pin site care
• Early rehabilitation (no frame obstruction)
• Faster return to function
• Precise control of distraction rate (0.1 mm steps)
• Can be combined with acute deformity correction (short-segment fixation)

Disadvantages

• Cannot correct angular/rotational deformity simultaneously (pure lengthening only - major limitation)
• Implant failure: fatigue fracture of nail reported (especially PRECICE STRYDE - recalled due to nail fractures)
• MRI incompatibility (distraction can occur inadvertently in MRI)
• High cost
• Requires second surgery for nail removal (after consolidation)
• Limited to femur and tibia (not applicable to humerus/fibula)
• Cannot compress across non-union (no compression function in PRECICE 2)
• Bone healing problems in adults (slower than children)

Complications

• Premature consolidation (distraction stops working - need to reactivate early)
• Fibrous non-union of regenerate (distraction too fast)
• Joint contracture (knee/hip)
• Axial deviation during lengthening
• Nail failure/fatigue fracture (STRYDE recall)
• Nerve palsy (peroneal nerve in tibial lengthening)

Results

• Up to 8 cm femoral lengthening achievable
• Healing index: 1-2 months/cm in adults (slower than children)
• High patient satisfaction scores

Q. RECENT ADVANCES IN MANAGEMENT OF POLYTRAUMA

Definition

Phases of Polytrauma Management

• Primary survey: ABCDE
• Resuscitation simultaneous
• Secondary survey after stabilisation

Recent Advances

• Bedside detection of haemoperitoneum, pericardial effusion, pneumothorax
• Extended eFAST: adds lung assessment
• Rapid, repeatable, no radiation

• CT head + neck + chest + abdomen + pelvis in single pass
• Time: 10-15 minutes
• Detects all injuries simultaneously
• Landmark Dutch trial (REACT-2): WBCT reduces mortality vs selective CT
• Now standard in major trauma centres

• Identifies vascular injuries, active bleeding
• Guides embolization planning

• TEG/ROTEM (Thromboelastography/Rotational Thromboelastometry): real-time coagulation assessment
• Guides targeted blood product resuscitation (fibrinogen, platelets, FFP)
• Lactate, base deficit: continuous monitoring

• Permissive hypotension: target SBP 80-90 mmHg (non-TBI), MAP 50 mmHg until haemorrhage control
• Haemostatic resuscitation: 1:1:1 ratio (RBC:FFP:Platelets) - simulates whole blood
• Massive Transfusion Protocol (MTP): activated early
• Tranexamic acid (TXA): within 3 hours of injury → reduces mortality by 15% (CRASH-2 trial)
• Fibrinogen concentrate / cryoprecipitate: early for coagulopathy
• Avoid hypothermia, acidosis, coagulopathy - "Lethal Triad"
• Whole blood transfusion: re-emerging, especially military/civilian

• Haemodynamic instability
• Coagulopathy
• Hypothermia (< 35°C)
• Acidosis (pH < 7.25)
• Severe TBI (GCS < 8)
• Severe pulmonary contusion

1. External fixator application (femur, pelvis, tibia)
2. ICU resuscitation and monitoring
3. Definitive fixation when physiologically stable (24-72 hours, after "window of opportunity")

• ETC (Early Total Care): immediate definitive fixation in stable patients
• DCO: temporary fixation in unstable patients

• Pelvic binder (T-POD, SAM Sling): immediate circumferential compression for open book injuries
• Extraperitoneal Packing (EPP): for venous/bony haemorrhage
• Angioembolisation: for arterial haemorrhage (superior gluteal artery most common)
• REBOA (Resuscitative Endovascular Balloon Occlusion of Aorta): emerging technique for junctional haemorrhage control - Zone 3 for pelvis

• "Window of opportunity" concept: 2-5 days early post-injury safer for definitive fixation
• MOF (Multi-Organ Failure) risk highest 4-6 days if inflammatory response peaks
• CRP, IL-6 monitoring guides timing

• WBCT standard (as above)
• Hybrid OR (operating room with fixed CT/DSA): simultaneous surgery + angiography
• AI-assisted trauma imaging: automated haemorrhage detection

• Intramedullary nailing of femur: earlier, lower threshold even in polytrauma
• Intraosseous access (IO): rapid vascular access for resuscitation drugs
• Negative pressure wound therapy (VAC): for soft tissue management, open fractures
• Portable CT (O-arm): intraoperative navigation for spine/pelvis

• Regional trauma networks / major trauma centres
• Trauma team activation protocols
• Helicopter Emergency Medical Services (HEMS)
• Pre-hospital TXA administration (London Ambulance Service)

Q. ORTHO-BIOLOGICS AND THEIR ROLE IN ORTHOPAEDICS

Definition

Classification

• Autologous plasma with 4-5× concentrated platelets
• Contains growth factors: PDGF, TGF-β, VEGF, IGF, EGF, FGF
• Preparation: centrifugation of autologous blood (single or double spin)
• Types: pure PRP (P-PRP), leukocyte-rich PRP (L-PRP), PRF (platelet-rich fibrin)
• Applications:
  • Knee OA: intraarticular PRP - symptom relief, possible cartilage-protective effect
  • Chronic tendinopathies (lateral epicondylitis, plantar fasciitis, Achilles)
  • Rotator cuff tear augmentation
  • Non-union: percutaneous PRP injection
  • Bone grafting: PRP + autograft improves healing

• Contains MSCs, haematopoietic progenitors, growth factors
• Harvested from posterior iliac crest, concentration by centrifuge
• Applications: AVN hip (core decompression + BMAC), non-union, OA, cartilage defects
• MSC content varies widely between patients and techniques

• BMP-2 (InFuse, Medtronic) and BMP-7 (OP-1, Stryker): FDA approved
• BMP-2: anterior lumbar spinal fusion, open tibial fractures
• BMP-7: recalcitrant long bone non-unions
• Mechanism: induces osteoblast differentiation from mesenchymal progenitors
• Concerns: BMP-2 in cervical spine → retrograde ejaculation, ectopic bone, cancer risk signals
• Cost: very high

• Second generation platelet concentrate
• Solid fibrin matrix + platelets + leucocytes
• No additives needed (just centrifugation)
• Used as membrane for wound healing, bone regeneration

• Intraarticular injection for knee OA
• Restores viscoelastic properties of synovial fluid
• Evidence: modest short-term benefit in mild-moderate OA

• Adipose-derived regenerative cells from lipoaspirate
• Contains MSCs, pericytes, endothelial precursors
• Point-of-care concentration
• Used for OA, AVN (experimental, regulatory restrictions)

• rhBMP-2, rhBMP-7 (as above)
• rhPDGF-BB (GEM 21S): periodontal/foot/ankle bone regeneration
• IGF, FGF: experimental

• Decellularised allografts (cartilage, meniscus, tendon matrices)
• Provide scaffold + retained growth factors

• Nano-sized extracellular vesicles from MSCs
• Carry miRNA, proteins
• Paracrine mediators of healing
• Cell-free alternative to stem cell therapy (avoids regulatory issues)

Regulatory Framework in India

• CDSCO regulates: PRP (minimal manipulation) vs expanded MSCs (substantial manipulation - regulated as drug)
• Avoid unproven commercial "stem cell treatments"

Q. DESIGNING OF ORTHOPAEDIC OPERATION THEATRE

Introduction

Location and Layout

• Ground floor preferred (heavy equipment, easy patient transfer)
• Separate from general OT complex (to reduce traffic contamination)
• Close to sterilisation department (CSSD) and ICU
• Dedicated trauma OT: 24-hour access

Zones of OT Complex

1. Outer zone (unrestricted): Staff change rooms, reception, waiting
2. Clean zone (semi-restricted): Scrub area, anaesthesia room, corridors
3. Aseptic zone (restricted): OT room proper, scrub sinks
4. Disposal zone: Exit corridor for contaminated material

OT Room Dimensions

• Orthopaedic OT: minimum 7.5 × 6 m (450 sq ft), ideally 7 × 7 m
• Ceiling height: minimum 3 m (for laminar flow canopy)
• Walls: seamless, non-porous, easy to clean (epoxy paint or PVC lining)
• Floors: anti-static, non-slip, seamless, easy to disinfect

Ventilation (Most Critical for Arthroplasty)

• 20-25 air changes/hour
• Positive pressure relative to adjacent areas
• HEPA filtration (99.97% efficiency for 0.3 μm particles)

• Vertical laminar flow (most common): downward unidirectional airflow over operating field
• Horizontal: sidewall direction (less used)
• 300-500 air changes/hour over operating field
• Bacterial counts: < 10 CFU/m³ (vs 180 CFU/m³ conventional)
• Mandatory for arthroplasty (reduces deep infection from 1.5% to 0.5-0.7%)
• Charnley enclosure + body exhaust suits (Surgeon in "space suit"): 0.5 CFU/m³

• Temperature: 18-22°C (prevents patient hypothermia, suits surgeon comfort)
• Humidity: 50-60% (reduces static electricity, prevents bacterial proliferation)

Special Equipment Requirements

• Radiolucent (carbon fibre) for C-arm access from any direction
• Orthopaedic table with traction attachments (Judet, Maquet, OSI Jackson)
• Fracture table for hip fractures (traction post, perineal post)
• 4-post frame for spine (Jackson table)
• Tilting, Trendelenburg, lateral tilt functions

• Mini C-arm (extremities) and standard C-arm
• Lead apron storage
• Ceiling-mounted lead shields
• Radiation monitoring equipment (dosimeter boards)

• Compressed air or battery-powered
• Dedicated storage and sterilisation rack for drills, saws, reamers

• Dedicated implant room adjacent to OT
• Orthopaedic implant sets: sets of screws, plates, nails, arthroplasty implants
• Loaner implant management protocol

• Video system (4K/HD camera), light source, shaver system, radiofrequency unit
• Inflow/outflow irrigation system

• Floor space: additional 4-6 sq m for robotic arm (MAKO robot)
• Separate electrical supply
• No ferromagnetic items (for electromagnetic navigation)

• Adjacent to OT for cast application
• Separate ventilation (plaster dust)
• Plaster sink with trap

Infection Control Measures

• Strict zoning and traffic control
• UV lights (overnight decontamination)
• Environmental sampling (settle plates)
• Terminal cleaning protocol
• Antibiotic prophylaxis integrated with OT workflow
• Air pressure cascade: OT > clean corridor > outer area

Electrical and Fire Safety

• Isolated electrical supply (IT system) with ELCI
• Anti-static flooring (prevent defibrillator spark)
• UPS backup for critical equipment
• Medical gas pipeline: O₂, N₂O, compressed air, vacuum
• No explosive anaesthetic agents near oxygen