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ORTHOPAEDIC EXAM PREPARATION - COMPREHENSIVE NOTES

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1. Management of MDR-TB

• Group A (use all three if possible): Levofloxacin/Moxifloxacin, Bedaquiline (Bdq), Linezolid (Lzd) - BPaL regimen
• Group B (add one/both): Clofazimine, Cycloserine/Terizidone
• Group C (add to complete regimen): Ethambutol, Delamanid, Pyrazinamide, Imipenem-cilastatin, Amikacin, Streptomycin, Ethionamide/Prothionamide, PAS

• 4-6 months: Bdq + Lzd + Lfx/Mfx + Cfz (intensive phase)
• 5-6 months: Lfx/Mfx + Cfz (continuation phase)

• Used when shorter regimen not applicable
• Minimum 4 effective drugs

• Bedaquiline + Pretomanid + Linezolid - 6 months duration
• Success rate ~89% for XDR-TB

• Surgery indicated for: neurological compromise, spinal instability, large abscess, failed conservative
• Anterior debridement + instrumented fusion (posterior or combined)
• Drug therapy continues regardless of surgery
• Duration: 18-24 months for bone TB, 9 months for pulmonary MDR-TB

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2. Designing of Orthopaedic Operation Theatre

1. Outer/Protective Zone - Changing rooms, reception, admin
2. Clean Zone - Scrub area, storage, corridors
3. Sterile/Aseptic Zone - Operating area, scrub sink area
4. Disposal Zone - Dirty utility, soiled linen exit

• Laminar Air Flow (LAF): Ultra-clean air for joint replacement
  • Vertical LAF preferred (ceiling mounted, 0.3 m/s velocity)
  • Air changes: 300/hour (LAF) vs 20-25/hour (conventional)
  • HEPA filters (99.97% efficiency for 0.3 µm particles)
• Positive pressure inside OT vs corridor
• Temperature: 18-22°C, Humidity: 40-60%

• Ceiling: 400 lux minimum
• Operating light: 20,000-100,000 lux, shadow-free, cool light
• Emergency lighting mandatory

• Isolated power supply (IPS)
• Anti-static flooring
• Multiple power outlets (for C-arm, navigation, diathermy, drill)
• Ceiling pendant preferred over floor cables

• Space for C-arm fluoroscopy
• Lead-lined walls if permanent X-ray in OT
• Lead aprons, thyroid shields, gonad shields stored nearby

• Traction table compatible room size
• Carbon fiber table for intraoperative imaging
• Navigation system space (camera tower, computer cart)
• Arthroscopy tower (monitor, pump, shaver) - ceiling or wall mounted
• Power tools (pneumatic/electric) - compressed air lines or electrical
• Implant storage - sterile storage room adjacent
• Scrub sink - knee-operated taps, 2 scrub stations minimum

• Isolates operative field
• 95% reduction in wound contamination
• Decreases deep infection in arthroplasty

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3. Nanotechnology in Orthopaedics

• Nano-hydroxyapatite (nHA): Mimics bone mineral crystite structure (20-80 nm), better osteoconductivity, osteointegration
• Carbon nanotubes (CNTs): High tensile strength scaffolds, electrical conductivity promotes osteogenesis
• Nano-fibrous scaffolds (PLGA, PCL): Electrospun fibers 50-500 nm diameter, mimic collagen fibril architecture
• Graphene oxide composites: Promote osteoblast differentiation

• Nanoparticles (PLGA, chitosan, liposomes): Controlled/sustained drug release
  • Antibiotics at surgical site (reduce infection)
  • BMP delivery for fracture healing
  • Bisphosphonate delivery for osteoporosis
• Nanostructured implant coatings: Vancomycin-loaded nanoparticles on implant surface
• Targeted delivery to tumor cells (in bone sarcoma)

• Nano-textured titanium surfaces: Increased osseointegration (nano-roughness 10-100 nm)
• Nanocoatings: Silver nanoparticles - antimicrobial (reduce periprosthetic infection)
• Nano-hydroxyapatite coating on implants: Better bone-implant contact

• Quantum dots: Fluorescent nanoparticles for tumor imaging, sentinel node biopsy
• Nano-contrast agents (iron oxide): MRI enhancement
• Nanosensors: Implantable sensors monitoring implant loosening, stress, infection

• Nano-fibrous scaffolds seeded with chondrocytes
• Self-assembling peptide nanostructures (RADA-16): Injectable scaffold for cartilage defects

• Hyperthermia via magnetic nanoparticles: Iron oxide nanoparticles in tumor + alternating magnetic field - generate heat, tumor ablation
• Nano drug carriers for targeted chemotherapy delivery

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4. Xenotransplantation in Orthopaedic Surgery

• Xenograft bone: Bovine (Bio-Oss), porcine bone - used as bone void fillers
• Processed to remove cells/antigens, retaining mineral scaffold
• Osteoconductive (scaffold) but not osteoinductive
• Used in: fracture void filling, spinal fusion, cavity filling after tumor excision

• Porcine xenograft cartilage for articular cartilage defects (experimental)
• Decellularized porcine cartilage ECM scaffolds

• Porcine small intestine submucosa (SIS) for tendon augmentation
• Processed porcine dermal matrix for rotator cuff repair

• Porcine decellularized meniscal scaffolds (experimental)
• Actifit (polyurethane) scaffolds inspired by meniscal xenograft research

• Nucleus pulposus replacement using porcine tissue (experimental)

• CRISPR-Cas9 knockout of porcine GGTA1 gene (removes alpha-gal epitope - main rejection antigen)
• Triple/quadruple gene knockout pigs under research
• 2022: First pig heart transplanted to human (Dr. Bartley Griffith, University of Maryland)

• Hyperacute rejection: HAR - within minutes, antibody-mediated (anti-alpha-gal antibodies)
• Acute vascular rejection: Days to weeks
• Cellular rejection: T-cell mediated
• Chronic rejection: Months to years

• Decellularization of tissues
• Genetic modification of pigs (alpha-gal knockout)
• Immunosuppression protocols
• Complement inhibition

• Rejection
• Zoonotic infection risk (PERV - Porcine Endogenous Retroviruses)
• Ethical concerns (animal rights, religious objections)
• Regulatory challenges
• Unknown long-term outcomes

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5. Cryotherapy in Orthopaedics

• Ice packs, cold compression devices
• Temperature: 0-15°C
• Used post-operatively, post-injury (RICE - Rest, Ice, Compression, Elevation)
• Mechanism: Vasoconstriction, reduced nerve conduction velocity, reduced inflammation, muscle spasm relief
• Duration: 20 min on, 20 min off
• Cryo-Cuff: Pneumatic compression + cold for post-arthroplasty

• Mechanism: Freeze-thaw cycles cause intracellular ice crystal formation, osmotic damage, vascular thrombosis, immune response
• Temperature achieved: -40°C to -196°C (liquid nitrogen = -196°C)
• Equipment: Cryoprobes (argon gas or liquid nitrogen), ultrasound or CT guidance

• Bone tumors (benign): Giant Cell Tumor (GCT) - cavity treated with cryotherapy after curettage to reduce local recurrence
• Aneurysmal Bone Cyst (ABC)
• Osteoid osteoma, osteoblastoma
• Soft tissue sarcomas (adjunct)
• Metastatic bone disease - pain palliation

1. Curettage of tumor
2. High-speed burr (extended curettage)
3. Liquid nitrogen instillation (2-3 freeze-thaw cycles)
4. Thaw, dry
5. Bone cement (PMMA) or bone graft filling

• Recurrence rate with cryotherapy: ~10-15% vs 25-50% curettage alone

• Skin/soft tissue frostbite (protective measures: warm saline packing, Vaseline gauze)
• Pathological fracture (freeze weakens bone temporarily - protect 6-8 weeks)
• Delayed wound healing
• Nerve damage (cryoneurolysis)
• Joint stiffness

• CT-guided cryoprobe insertion
• For painful bone metastases, osteoid osteoma
• Less invasive than open surgery

• Chambers at -110°C to -140°C, 3-5 minutes exposure
• Used in sports medicine: recovery, inflammation reduction
• Evidence: moderate benefit in muscle recovery, pain, inflammation markers

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6. Radiation Hazards in Orthopaedics - Preventive Measures

• Intraoperative fluoroscopy (C-arm) - most significant source
• Image Intensifier (II)
• Fluoroscopy for spinal procedures, joint arthroplasty, fracture fixation
• CT for navigation, planning

• Absorbed dose: Gray (Gy) = J/kg
• Effective dose: Sievert (Sv) - accounts for tissue sensitivity
• Exposure: Roentgen (R)
• Natural background: ~3 mSv/year
• Permissible dose: 20 mSv/year (occupational), 1 mSv/year (public), 50 mSv in any single year

• Stochastic effects (no threshold): Malignancy (leukemia, thyroid cancer), hereditary effects
• Deterministic effects (threshold): Skin erythema, cataracts, radiation burns (>2 Gy)
• Highest risk organs: bone marrow, thyroid, gonads, eyes (lens - cataracts)

• Intermittent fluoroscopy (pulsed mode) - reduces dose 50-90%
• Store fluoroscopy image ("last image hold") - study static image rather than live fluoroscopy
• Minimize screening time - plan, execute, minimize

• Inverse Square Law: dose ∝ 1/distance²
• Every doubling of distance reduces dose to 1/4
• Step back when not actively imaging (minimum 2 meters)
• Remote controls for image acquisition

• Lead aprons: 0.25-0.5 mm lead equivalent, reduces scatter by 90-95%
  • Full wrap-around preferred
• Thyroid shields (collar): 0.25-0.5 mm lead - thyroid is most radiosensitive
• Lead glasses/goggles: Reduce lens dose - cataracts are professional risk
• Lead gloves (0.25 mm): For hands near beam (but reduce tactile feedback)
• Radiation barrier (screen): Lead acrylic screens, pull-in barriers
• Lead-lined OT walls if fixed X-ray units

• Image Intensifier positioning: II close to patient, X-ray tube far (tube under table preferred - reduces scatter to operator)
• Collimation: Cone down beam to area of interest - reduces scatter
• Pulsed fluoroscopy: 1-4 pulses/sec vs 30/sec continuous
• Digital detectors (flat panel) vs old image intensifiers - less radiation needed
• Lateral beam - more scatter than PA; use wedge filters

• Thermoluminescent dosimeter (TLD) or OSL (optically stimulated luminescence) dosimeters
• Worn at collar level (outside apron) and waist (under apron)
• Monthly/quarterly dose review
• Dose record maintenance throughout career

• Pregnant staff: Transfer away from fluoroscopy room; if working, additional abdominal shield; fetal dose limit 1 mSv for remainder of pregnancy
• Hands: Most exposed - hands in field during K-wire insertion; use fluoroscopy tongs/drill guides
• Training: Radiation safety training for all OT staff

• Pedicle screw insertion (spine): highest dose
• Hip arthroplasty (especially cup positioning)
• Intramedullary nailing (distal locking)
• Percutaneous fracture fixation

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7. Autologous Chondrocyte Implantation (ACI) & Masquelet Technique

Autologous Chondrocyte Implantation (ACI)

• 1st generation ACI: Periosteal patch cover - graft harvested from knee margin, chondrocytes injected under it
• 2nd generation ACI: Collagen membrane (MACI uses type I/III collagen membrane) - replaces periosteum
• 3rd generation MACI (Matrix-induced ACI): Chondrocytes seeded onto 3D collagen-glycosaminoglycan scaffold, arthroscopic implantation possible

• 200-300 mg cartilage from non-weight-bearing margin (trochlea, intercondylar notch)
• Cells isolated by collagenase digestion, cultured in GMP lab for 3-4 weeks
• Expansion: 200,000 → 12-48 million cells

• Open (mini-arthrotomy) or arthroscopic
• Debride defect to stable rim, perpendicular walls, subchondral bone preserved
• MACI membrane cut to shape, chondrocyte side down
• Fibrin glue fixation + sutures to periosteum
• Rehabilitation: Non-weight bearing 6 weeks, gradual progression, return to sports 12-18 months

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Masquelet Technique (Induced Membrane Technique)

• Radical debridement of dead bone, infection
• Stabilization with external fixator or locked nail
• Fill defect with antibiotic-loaded PMMA cement (vancomycin + gentamicin)
• Primary wound closure
• Wait 4-8 weeks (up to 12 weeks)
• Induced membrane formation: Cement induces a vascularized pseudo-synovial membrane rich in growth factors (BMP-2, VEGF, TGF-β), acts as biological reactor

• Do NOT excise the membrane - preserve it as a bioreactor
• Make a window in the membrane
• Remove cement spacer
• Fill with autologous bone graft (reamer-irrigator-aspirator RIA from femur, or iliac crest)
• Close the membrane window
• Continue stabilization until union

• Prevents graft resorption
• Provides vascularity
• Secretes growth factors (BMP-2, VEGF, TGF-β1)
• Acts as bioreactor

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8. All-Inside Technique for Meniscal Repair

• Fast-Fix (Smith & Nephew): Pre-tied slipknot, two anchor bars connected by suture
• Meniscal Cinch (Arthrex)
• MaxFire MarXmen (Biomet)
• Sequent (ConMed)

1. Arthroscopic assessment - confirm tear pattern, location, vascularity (red-red, red-white, white-white zones)
2. Tear preparation: Rasping/abrading both surfaces to enhance healing response
3. Device insertion through cannula/portal
4. First anchor deployed through tear into meniscal tissue on capsular side
5. Second anchor deployed on joint side
6. Suture tightened using tensioning device (slipknot advances, compresses tear)
7. Multiple passes 3-5 mm apart along tear length
8. Final tensioning to achieve coaptation

• No accessory incisions (no posteromedial/posterolateral approach)
• Faster procedure, reduced operative time
• Reduced risk of neurovascular injury (saphenous nerve, common peroneal nerve, popliteal vessels)
• No posteromedial/lateral skin scars
• Can repair posterior horn tears more safely
• Less soft tissue dissection

• Higher implant cost vs outside-in or inside-out
• Device failure risk (implant breakage, anchor pull-out)
• Suture laxity - may not achieve as rigid fixation as inside-out sutures
• Learning curve
• Implant left in joint (foreign body concern, although bioabsorbable implants reduce this)
• Not suitable for all tear patterns
• Risk of prominent implant causing chondral damage
• Bioabsorbable implants can cause synovitis

• Outside-in: Best for anterior horn; outside to inside needle technique
• Inside-out: Gold standard for body/posterior horn; cannula technique, requires accessory incision for knot tying outside capsule
• All-inside: Best for posterior horn; fastest; no additional incisions

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9. Navigation in Total Knee Arthroplasty (TKA)

1. Image-based: Pre-op CT scan, intraoperative registration to CT model
2. Imageless navigation: Intraoperative landmark digitization, no pre-op imaging
3. Fluoroscopy-based: Real-time fluoroscopy guidance
4. Robotic-assisted: Active (MAKO, TSolution One), semi-active (Navio), passive

1. Reference arrays attached to femur and tibia (fixed with pins)
2. Infrared camera tracks arrays in real-time
3. Surgeon digitizes landmarks: femoral head center (hip circumduction), knee center, ankle center
4. Software calculates mechanical axis, joint line orientation
5. Real-time feedback on: cut position/orientation, component alignment, balance

• Accuracy: Reduces outliers (>3° from neutral mechanical axis) from 20-30% to <5%
• Consistency: Independent of patient habitus (obese patients, small femoral canal)
• Reduced radiation: No intraoperative fluoroscopy
• Real-time feedback: Soft tissue balance assessment, gap balancing
• Useful in: Deformed anatomy, previous fracture/osteotomy, extra-medullary rods

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TKA in Fixed Flexion + Valgus Deformity

• Posterior capsule release: Key step - cruciate-like release from femur
• Adequate posterior femoral condyle resection: Increase distal femoral cut (1-2 mm extra) or use augments
• Slope modification: Increased posterior tibial slope helps extension (0-3° only)
• Do NOT over-resect tibia to compensate - leads to joint line elevation
• Bone cuts first approach (gap balancing) vs measured resection
• Extension gap priority: After releases, re-check extension gap
• Up to 20° FFD can be corrected intraoperatively
• If >20°: may need sequential releases; residual <5-10° FFD usually resolves with physiotherapy
• Final check: Manual passive extension intraoperatively; confirm correction

• Type I: <10° valgus, normal bone stock
• Type II: 10-20° valgus, bone deficiency
• Type III: >20° valgus, severe deformity

1. Iliotibial band (ITB) - Z-plasty or pie-crusting
2. Lateral capsule
3. Popliteus tendon (partial)
4. Lateral head of gastrocnemius
5. LCL (controversial - avoid if possible)
6. PCL in CR knees

• Lateral femoral condyle hypoplasia: Reduce lateral femoral resection; use augments; adjust cutting jig
• Lateral tibial plateau erosion: Bone cement augments or modular augments

• Accurately determines mechanical axis in valgus where extramedullary alignment is unreliable
• Real-time balance assessment after releases
• Avoids over-resection

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10. Acetabular and Femoral Component Version in THR

• Anteversion: Forward rotation of component from reference plane
• Acetabular anteversion: 15-25° (Lewinnek safe zone: 15±10°)
• Acetabular inclination (abduction): 30-50° (Lewinnek: 40±10°)
• Femoral anteversion: 10-15° (normal native ~15°)

• Proposed by Widmer & Zurfluh (2004)
• Combined anteversion = Acetabular anteversion + 0.7 × Femoral anteversion
• Target: 37-42° (Widmer's target)
• Goal: Ensure hip stability through range of motion; no single component safe zone independently adequate
• Accounts for the kinematic coupling between cup and stem anteversion

• Lateral decubitus: Standard; cup anteversion guided by floor/table reference
• Pelvis must be truly perpendicular to table (use sacrum, pubic symphysis landmarks)
• Anterior pelvic tilt in lateral position adds functional anteversion
• Posterior pelvic tilt reduces effective anteversion

1. Mark anterior superior iliac spines bilaterally
2. Check pelvis perpendicular using spirit level or navigation
3. Acetabular reaming in correct inclination/version using anatomic landmarks (transverse acetabular ligament as reference for version/inclination)
4. Transverse Acetabular Ligament (TAL): Aim cup opening parallel to TAL (indicates native acetabular orientation)
5. Final cup insertion: impactor guide at 40° abduction, 15-25° anteversion from sagittal plane
6. Verify with intraoperative AP and lateral views (fluoroscopy or navigation)

1. Prepare femoral canal with broaches in neutral rotation
2. After canal preparation, assess native anteversion (with knee at 90°, angle of femoral neck from vertical = anteversion)
3. Modular stems: Dial in version by rotating stem in canal
4. Monobloc stems: Version determined by broach orientation
5. Final stem insertion: typically 10-15° anteversion (antevert stem toward femoral neck)
6. Trial reduction and impingement testing through ROM
7. Navigate using reference to femoral condyles (posterior condylar axis as reference)

• Hyperlordosis causes anterior pelvic tilt when standing
• Anterior pelvic tilt = cup becomes less anteverted functionally (cup tilts forward/faces more posteriorly)
• Higher risk of anterior dislocation in functional position
• Modification: Increase acetabular anteversion by 5-10° (target 20-30° cup anteversion)
• Alternatively: Increase femoral anteversion slightly
• Goal: Compensate for functional retroversion of cup

• Flat back = posterior pelvic tilt when standing
• Posterior pelvic tilt = cup becomes more anteverted functionally
• Risk of posterior dislocation in functional position
• Also: When sitting, spine flattens → pelvis tilts posteriorly → cup becomes even more anteverted → posterior instability with flexion activities
• Modification: Decrease acetabular anteversion (target 10-15°) to avoid over-anteversion in functional position
• Consider increased femoral anteversion to maintain combined anteversion
• Pre-op planning with EOS imaging or hip-spine analysis recommended

• Pelvic Incidence (PI): Fixed anatomical angle; PI = pelvic tilt + sacral slope
• Spinal-Pelvic Mismatch: Stiff lumbar spine cannot compensate; cup position must be modified
• High PI patients: At risk for posterior instability
• "Safe Zone" shifts based on functional position, not just supine radiographs

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11. Minimally Invasive Spinal Surgeries (MISS)

• Reduce iatrogenic muscle damage (paraspinal muscle denervation, atrophy)
• Less blood loss, shorter hospital stay, faster recovery
• Equivalent clinical outcomes to open surgery

• 16-18 mm tubular retractor system
• Endoscope + microscope visualization
• For lumbar disc herniation - equivalent to open discectomy with less muscle trauma
• Indication: Unilateral disc herniation, failed conservative ≥6 weeks

• Jamshidi needle insertion under fluoroscopy (AP + lateral)
• K-wire passage, cannulated pedicle probe, cannulated screws
• No open dissection; sextant/Longitude systems
• Indication: Thoracolumbar fractures, degenerative spondylolisthesis (combined with MISS fusion)

• Bilateral tubular retractors + microscope
• Unilateral facetectomy, discectomy, cage insertion, bilateral pedicle screws
• Indication: Degenerative spondylolisthesis, recurrent disc herniation, isthmic spondylolisthesis
• Advantages: Less blood loss (50 vs 500 mL), shorter stay, similar fusion rates

• Retroperitoneal approach via psoas muscle (transpsoas)
• Neuromonitoring (EMG) to protect lumbar plexus within psoas
• Large interbody cages restore disc height, indirect decompression
• Indication: Degenerative disc disease L1-L4 (not L4-L5 due to high iliac crest and plexus risk)

• Oblique retroperitoneal corridor anterior to psoas, avoiding psoas split
• Less lumbar plexus risk vs XLIF; can access L4-L5 and L5-S1
• Supplemented with posterior percutaneous screws

• Full-endoscopic technique (Joimax, Richard Wolf)
• Transforaminal or interlaminar approach
• 7-8 mm working channel, direct visualization
• Day surgery procedure
• Learning curve steep

• ULBD (Unilateral Laminotomy for Bilateral Decompression)
• Via unilateral tubular retractor; microscope angled to opposite side to decompress bilateral stenosis
• Preserves interspinous ligament, spinous process, contralateral musculature

• Percutaneous cement augmentation for osteoporotic vertebral compression fractures
• Kyphoplasty: Balloon inflation first → restore height, then cement under lower pressure
• Risks: Cement extravasation, embolism

• Inaccurate screw placement (without navigation)
• Neurological injury (narrow corridor)
• Increased radiation exposure to surgeon (more fluoroscopy)
• Learning curve - initial longer operative times

• Intraoperative CT-guided navigation
• Significantly improves pedicle screw accuracy
• Reduces radiation to surgeon (though higher patient dose during CT acquisition)

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12. Stoppa's Approach (Modified Stoppa / Pararectus Approach)

• Midline or Pfannenstiel (transverse suprapubic)
• Lower midline: from umbilicus to pubic symphysis
• Pfannenstiel: 2-3 cm above pubic symphysis, transverse, cosmetically superior

1. Skin incision (midline or Pfannenstiel)
2. Linea alba/rectus sheath opened
3. Rectus abdominis muscles retracted laterally (not detached)
4. Space of Retzius (retropubic space) entered - preperitoneal space
5. Peritoneum and contents retracted superiorly and laterally
6. Corona mortis (anastomosis between external iliac and obturator vessels) identified and ligated if present (30-70% of patients)
7. Obturator nerve and vessels identified and protected
8. Quadrilateral surface exposed
9. Bone retractors placed on pelvic brim

• Corona mortis (abnormal vascular connection - can cause torrential hemorrhage if torn)
• Obturator nerve (must be visualized throughout)
• Iliac vessels (retracted medially)
• Urinary bladder (retracted medially - Foley catheter mandatory)
• Vas deferens/round ligament

• Acetabular fractures: Anterior column, anterior wall, transverse, T-type, anterior column-posterior hemitransverse (ACPHT), both-column fractures
• Provides excellent visualization of quadrilateral surface, posterior column from inside
• Reduces need for external rotation/dislocation of femoral head

• Superior visualization of quadrilateral surface and posterior column (vs ilioinguinal approach)
• Avoids division of inguinal ligament and iliac muscle retraction (less morbidity than ilioinguinal window II)
• Lower incidence of lateral femoral cutaneous nerve injury
• Allows access to both sides if bilateral fractures
• Less dissection plane creation - reduces dead space
• Can be combined with Kocher-Langenbeck for complex patterns

• Limited access to iliac wing (vs ilioinguinal approach window I)
• Risk of bladder injury
• Risk of devastating corona mortis hemorrhage
• Learning curve
• Risk to vas deferens (reproductive complications in males)

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13. Fragility Fractures

• Reduced bone mineral density (BMD) - T-score ≤ -2.5
• Deteriorated bone microarchitecture
• Increased bone resorption/decreased formation (age-related, menopausal, secondary causes)

• Fracture fixation: Must be primary goal - augmented implants (intramedullary nails > plates), cement augmentation of screws
• PMMA augmentation: Inject cement around screws/pegs to improve pullout strength
• Locked implants: Angular stability critical (locking plates, cephalomedullary nails)
• Proximal femur: Early surgery (<48 hours) reduces mortality; cemented hemiarthroplasty or THA (active, mobile patients); cephalomedullary nail for stable fractures
• Distal radius: ORIF with volar locked plate (vs cast - poor functional outcomes in elderly)
• Vertebral fractures: Kyphoplasty/vertebroplasty for painful fractures; conservative for stable fractures
• Pelvic insufficiency: Usually conservative; fixation if unstable (percutaneous iliosacral screws, TITS technique)

• Calcium + Vitamin D: All patients; Ca 1200 mg/day, Vit D 800-1000 IU/day
• Bisphosphonates (first-line): Alendronate, Risedronate, Zoledronic acid (annual infusion - preferred post-fracture, can give within 2 weeks of fracture)
• Denosumab: RANKL inhibitor, 60 mg SC every 6 months; preferred if renal impairment
• Teriparatide (PTH 1-34): Anabolic; 20 µg SC daily for 2 years; best for severe osteoporosis, high fracture risk
• Romosozumab: Sclerostin inhibitor; 210 mg SC monthly × 12 months; dual anabolic+antiresorptive; recent FDA/CE approved

• Identify and treat ALL fragility fracture patients for osteoporosis
• FLS coordinator coordinates: DXA scan, falls assessment, medication initiation
• Reduces subsequent fracture risk 30-50%

• Balance training, physiotherapy
• Vitamin D (reduces falls)
• Hip protectors (reduce hip fracture risk ~30% if worn)
• Environmental modification (grab rails, non-slip mats)
• Medication review (reduce sedatives, antihypertensives)
• Vision correction

• Sequential therapy: Start with anabolic (teriparatide/romosozumab) → transition to antiresorptive (bisphosphonate/denosumab) for maximum benefit
• Romosozumab (Evenity): Approved 2019; FRAME trial showed 73% vertebral fracture reduction
• FLS (Fracture Liaison Service): Best evidence model for secondary prevention; Capture the Fracture program (IOF)
• IOF Capture the Fracture® initiative: Global benchmarking program
• Zoledronic acid immediately post-hip fracture: HORIZON-RFT trial - reduces mortality 28% AND further fractures
• Implant innovations: Calcium phosphate-coated locking screws, HELICOIL technology (bone thread tapping), suture augmentation
• Cement augmentation (PHILOS-HA, PROXIMA): For proximal humerus fixation in osteoporotic bone
• Intraosseous infusion (Traumafix, CIRTM): Cement injection through cannulated screws

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14. 3D Printing in Orthopaedics

• Stereolithography (SLA): UV resin photopolymerization
• Selective Laser Sintering (SLS): Powder bed fusion
• Fused Deposition Modelling (FDM): Thermoplastic extrusion
• Electron Beam Melting (EBM): Metal powder (titanium, cobalt-chrome)
• Direct Metal Laser Sintering (DMLS): Most common for implants

• 1:1 scale anatomical models from CT data
• Pre-operative simulation of complex fractures (acetabular, periarticular)
• Rehearsal of surgical steps
• Patient education
• Cost: $100-500 per model

• Patient-specific jigs for osteotomies (HTO, DFO, pelvic osteotomy)
• Reduce outliers in component positioning
• Pediatric deformity correction (FCO - functional position custom osteotomy)
• Reduce operative time, reduce instrumentation

• Large bone tumor resections (proximal femur, pelvis, scapula)
• Periacetabular implants for failed THR with massive bone loss
• Titanium cages for spinal reconstruction after corpectomy
• Cranio-maxillofacial reconstruction

• 3D-printed porous titanium: Trabecular Metal-like structures
• Porosity 60-80%, pore size 400-600 µm (optimal for osteointegration)
• Better biological fixation than conventional smooth implants
• Used in: spinal cages (PEEK vs titanium), acetabular cups, revision implants

• Custom 3D-printed AFO, wrist splints
• Pediatric prosthetics (low cost)

• Bioink = living cells + hydrogel scaffold
• Print cartilage, bone, intervertebral disc with cells
• Currently experimental - vascularization challenge remains

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15. Role of Artificial Intelligence in Orthopaedics

• Machine Learning (ML): Learns from data without explicit programming
• Deep Learning (DL): Multi-layer neural networks; best for image analysis
• Natural Language Processing (NLP): Text analysis from clinical notes
• Computer Vision: Radiograph/MRI/CT analysis

• Automated fracture detection on X-rays (Gleamer BoneView, Axia Health AI) - sensitivity ~90%
• Bone age assessment (paediatric orthopaedics) - AI vs Greulich-Pyle atlas (AI = similar accuracy, much faster)
• Osteoporosis screening from plain X-rays or DXA
• Tumour characterization (benign vs malignant on MRI/CT)
• Hip dysplasia screening in infants (ultrasound AI)
• OA grading (Kellgren-Lawrence) from knee X-rays (validated AI tools)

• Automated templating for THR/TKA (implant size, position)
• Deformity correction planning (osteotomy planning)
• Spine alignment analysis (Cobb angle, sagittal balance automated)

• AI-powered robots (MAKO, ROSA): Plan and execute bone cuts based on pre-op 3D CT data
• Haptic feedback limits to prevent over-cutting
• Consistently achieve planned alignment

• Predict surgical outcomes, complications
• Identify patients at high risk of implant failure, revision
• Predict LOS, readmission (for resource planning)
• FORCE-TJR registry ML models for predicting PROMs

• Real-time image guidance
• Soft tissue tension monitoring
• Balance assessment in TKA

• Automated coding from operative notes
• Extract data from clinical records for registry
• AI-driven chatbots for patient education/follow-up

• AI-powered wearable sensors for gait analysis
• Rehabilitation monitoring, compliance tracking
• Exoskeleton control algorithms

• Literature mining, hypothesis generation

• Data quality/bias (training data demographics)
• Black box problem (interpretability)
• Regulatory clearance (FDA, CE)
• Integration with existing HIS/PACS
• Liability and accountability
• GDPR/HIPAA compliance (data privacy)
• Cost of implementation

• Gleamer BoneView (fracture detection)
• Imagen OsteoDetect (wrist fracture)
• Zebra Medical Vision (osteoporosis)

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16. Ortho-Biologics and Their Role in Orthopaedics

• Source: Iliac crest; centrifugation concentrates MSCs, growth factors, platelets
• Contains: MSCs (~1-2%), hematopoietic cells, platelets, cytokines
• Applications: Augment fracture healing, non-union, osteonecrosis (core decompression + BMAC), cartilage defects, tendinopathy
• Evidence: Moderate - accelerates healing in non-union, early AVN

• Autologous blood centrifuged to concentrate platelets (4-8× baseline)
• Contains: PDGF, TGF-β, VEGF, IGF, EGF, FGF
• Types:
  • Leukocyte-rich PRP (L-PRP): Higher inflammatory response (tendons)
  • Leukocyte-poor PRP (LP-PRP): Less inflammatory (joints/cartilage)
  • Activated (with thrombin/CaCl₂) vs non-activated
• Applications:
  • Knee OA: Intra-articular injection (better than HA in early OA per meta-analyses)
  • Tendinopathy: Patellar, Achilles, lateral epicondylitis
  • Rotator cuff repair augmentation
  • Fracture healing augmentation
• Evidence: Moderate for knee OA and tendinopathy; limited for fractures

• Allograft bone with mineral removed (acid extraction)
• Retains collagen + growth factors (BMP-2, BMP-7, TGF-β)
• Osteoinductive + osteoconductive
• Forms: Putty, gel, strips, chips (e.g., Grafton, DBX, Accell)
• Applications: Spinal fusion (mixed with local autograft), fracture void filling, non-union augmentation
• Limitation: Variable BMP content between donors/lots; batch testing needed

• TGF-β superfamily; most potent osteoinductive agents
• rhBMP-2 (InFUSE, Medtronic): FDA approved for:
  • ALIF (anterior lumbar interbody fusion) L4-S1
  • Open tibial shaft fractures (ATA study)
  • Sinus augmentation, ridge augmentation
• rhBMP-7 (OP-1, Osigraft): For tibial non-union
• Carrier: Absorbable collagen sponge (ACS)
• Complications: Ectopic bone formation, osteolysis (spinal), retrograde ejaculation (ALIF), seroma, inflammation
• Off-label use: Posterolateral spinal fusion, non-union - evidence variable

• Similar to PRP but richer in growth factors; centrifugation protocol different

• Not strictly biological but biological origin
• Intra-articular injection for knee OA
• Mechanism: Restore synovial fluid viscosity, anti-inflammatory
• Evidence: Modest symptomatic benefit; meta-analyses show small but real effect
• Effect lasts 4-6 months

• Amniotic membrane allograft: Anti-inflammatory, anti-fibrotic, growth factors
• Applications: Tendon repair augmentation, wound healing, rotator cuff
• Regulatory status: Section 361 HCT/P (FDA) if minimally processed

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17. Stem Cells in Orthopaedics

• Source: Bone marrow, adipose tissue, synovium, periosteum, umbilical cord
• Can differentiate into: Osteoblasts, chondrocytes, tenocytes, myocytes
• Immunomodulatory properties (paracrine effects)
• Most studied for orthopaedic applications

• Pluripotent; derived from inner cell mass of blastocyst
• Ethical concerns; teratoma risk; limited orthopaedic use

• Adult somatic cells reprogrammed to pluripotency (Yamanaka factors: Oct4, Sox2, Klf4, c-Myc)
• Patient-specific, no immune rejection
• Risk: Oncogenicity; manufacturing complexity

• Easily harvested from lipoaspirate; abundant
• Similar to BMAC-MSCs
• Stromal Vascular Fraction (SVF): Point-of-care adipose processing

• Non-union treatment: MSCs (BMAC) + scaffold + growth factors
• Distraction osteogenesis enhancement
• Osteonecrosis (AVN femoral head): Core decompression + MSC injection - delays/prevents collapse in early stages

• MSC intra-articular injection for knee OA - symptomatic relief, possible structure modification (under study)
• MSC-based cartilage tissue engineering (cell-seeded scaffolds for ACI evolution)
• Autologous Matrix-Induced Chondrogenesis (AMIC): MSC + collagen matrix

• MSC injection for Achilles tendinopathy, rotator cuff augmentation
• Accelerates tendon healing in animal models; human trials ongoing

• NP cell replacement with MSCs for disc regeneration
• Intradiscal MSC injection - Phase II trials showing disc hydration improvement

• MSC injection post-meniscectomy for regeneration potential

• FDA classifies cell therapies as biologics (BLA required)
• Significant differences between FDA (strict) and some other countries
• Stem cell tourism/unregulated clinics: Patient safety concern
• Teratoma risk with iPSC/ESC
• Long-term efficacy data limited
• Standardization of MSC products (cell dose, passage number, carrier)

• BMAC (concentrated bone marrow) widely used (minimal processing = 361 exempt)
• Commercially prepared MSC products require full approval
• Several Phase III trials underway (knee OA, disc degeneration)

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18. Recent Advances in Management of Severely Osteoporotic Fractures of Long Bones

• Poor bone quality: Reduced pullout strength, increased risk of cut-out, peri-implant fractures
• Healing impaired: Reduced angiogenesis, osteoblast activity, growth factor expression
• Patient factors: Elderly, comorbidities, limited rehabilitation potential

• Helical blade (TFNA, PFN-A): Compacts cancellous bone during insertion (vs cutting thread) → better rotational control, lower cut-out rates
• Augmentation options: Cement injection through blade (TFNA Augmentation) - dramatically improves pullout strength (3-5×)
• Dual lag screw (Endovis BA, InterTAN): Locks 2 screws together to prevent rotation

• PHILOS Augmentation (DePuy): PMMA cement through dedicated holes in plate
• Spiral blade (MultiLoc): Compacts bone like helical blade in femur
• Increasing trend to primary arthroplasty (RSA - reverse shoulder arthroplasty) for 3-4 part fractures in elderly - better predictable outcomes vs ORIF

• Locked plates (LISS, LCP) - angular stability; fixed-angle screws provide stability in porotic bone
• Calcium phosphate bone substitute injection to fill metaphyseal void

• Calcium sulfate/phosphate cements: Osteoconductive; fills dead space, support subchondral bone
• Injectable bone substitutes (CERAMENT, HydroSet): Remodeling into bone over 6-12 months
• BMP augmentation: Off-label for non-union risk cases
• Systemic anabolic therapy (Teriparatide): May accelerate fracture healing in osteoporotic fractures; enhances callus formation (TOWER trial evidence)

• Cemented hemiarthroplasty/THA for displaced intracapsular hip fractures: Cemented stems superior in osteoporotic bone vs cementless (HEALTH, SAVE trials)
• RSA (Reverse Shoulder Arthroplasty) for complex proximal humerus fractures in elderly

• Load-sharing; better than plates for diaphyseal fractures in osteoporotic bone
• Expandable nails (Fixion Nail): Hydraulically expanded after insertion - better contact with cortex
• Flexible intramedullary nails + augmentation (ender-type + cement): Experimental

• Early surgery (<48h) for hip fractures: AO/OTA guidelines; reduces mortality, complications
• Orthogeriatric co-management model: Dedicated orthogeriatric ward; reduces complications, LOS, mortality
• Enhanced Recovery After Surgery (ERAS): Regional anaesthesia, early mobilization, multimodal analgesia

• Initiate anti-osteoporotic therapy during index admission
• Zoledronic acid IV: Can give 2 weeks post-fracture; does not impair healing; reduces mortality (HORIZON-RFT trial)
• Fracture Liaison Service (FLS) mandatory for all orthopaedic units

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19. Motorized Intramedullary Bone Lengthening in Adults

• PRECICE (NuVasive/Ellipse): External remote controller (ERC) with rotating magnetic field drives internal mechanism; 1 mm/day rate
• STRYDE (NuVasive): Load-sharing design; titanium vs stainless steel (PRECICE); allows weight-bearing during lengthening
• FITBONE (Wittenstein): Implanted motor, electrical stimulation transcutaneous
• ISKD (Intramedullary Skeletal Kinetic Distractor): Rotational movement during gait drives lengthening (no active control - risk of uncontrolled lengthening)
• PHENIX: French device

• Ilizarov's tension-stress principle
• 3 phases: Latency (5-7 days), Distraction (1 mm/day), Consolidation (2× distraction period)
• Rate: 1 mm/day in 4× 0.25 mm increments preferred

• Limb length discrepancy (LLD): >2 cm (symptomatic); any cause
• Short stature (achondroplasia, hypochondroplasia, other skeletal dysplasias)
• Post-traumatic/infection LLD
• Congenital deficiency (fibular hemimelia, PFFD)
• Combined with deformity correction (transport nail for non-union + LLD)

1. Osteotomy (corticotomy): Low energy, preserve periosteum; subtrochanteric (femur), supratuberosity (tibia)
2. Nail insertion across osteotomy
3. Latency period (5-7 days) - allow early callus
4. Distraction: Patient/family activates ERC daily (PRECICE); 0.25 mm × 4/day = 1 mm/day
5. Monitor: Fortnightly X-rays, weekly physiotherapy
6. Consolidation: Nail remains as internal fixation until full consolidation
7. Nail removal after consolidation (12-18 months total)

• No external frame - vastly improved quality of life, comfort
• No pin site infection risk
• Improved patient compliance
• Enables normal gait pattern during treatment
• Weight-bearing allowed (STRYDE)
• Showering, hygiene unaffected
• Psychological advantage (no external hardware visible)

• Higher cost (implant cost $15,000-35,000)
• Requires second surgery for nail removal
• Cannot adjust rate easily (once programmed)
• Risk of premature consolidation (if lengthening too slow) or non-union (too fast)
• Joint contracture risk (soft tissue limiting factor) - aggressive physiotherapy mandatory
• No ability to correct deformity simultaneously (vs TSF/Ilizarov which can do 6D correction)
• Nail failure (fatigue fracture) - risk with PRECICE for large lengthenings
• MRI incompatible (device artifact; some limited compatibility)
• Not suitable for very small canals (narrow medullary canal)

• X-ray every 2 weeks during lengthening (regenerate quality)
• If premature consolidation: Back-distract, bone stimulation
• Nerve function: Daily check (pain with distraction = pause)
• Joints: Daily ROM physiotherapy mandatory
• Stop if regenerate shows insufficient mineralization

• Success rate ~90%+ for LLD
• Average lengthening: 5-8 cm femur, 4-6 cm tibia per procedure
• Consolidation index: 30-40 days/cm (similar to external fixation)

• Joint stiffness (most common)
• Axial deviation during lengthening
• Premature consolidation
• Delayed consolidation / non-union
• Nerve palsy (peroneal nerve in tibia - stop distraction immediately)
• Implant failure (nail fracture)
• Infection (rare vs external fixation)

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20. Recent Advances in Management of Polytrauma Patients

• Permissive hypotension: Target MAP 50-65 mmHg (SBP 80-90) until hemorrhage controlled - reduces coagulopathy, hypothermia
• Hemostatic resuscitation (1:1:1): FFP:Platelets:RBC ratio = 1:1:1 (PROPPR trial); early activation of massive transfusion protocol (MTP)
• TXA (Tranexamic Acid): CRASH-2 trial - give within 3 hours of injury; reduces mortality from hemorrhage; 1g IV bolus then 1g over 8 hours
• Whole Blood: Return to fresh whole blood transfusion in severely injured
• Viscoelastic testing (TEG/ROTEM): Goal-directed coagulation management; fiber-based resuscitation guidance
• Calcium supplementation: With massive transfusion (citrate chelates calcium)

• Primary concept: Temporize fracture stabilization (external fixator) → definitive fixation after physiological restoration
• Indication for DCO: Unstable polytrauma (ISS >40, pH <7.2, temp <35°C, lactate >2.5, coagulopathy, pulmonary contusion, TBI)
• "Lethal Triad": Hypothermia + Acidosis + Coagulopathy - DCO prevents exacerbation
• Early Total Care (ETC): For stable polytrauma - immediate definitive fixation (IMN) is safe and preferred
• Borderline patient: Reassess every 6-12 hours; if deteriorating → DCO; if stable → ETC

• FAST (Focused Assessment with Sonography in Trauma): Extended FAST (eFAST) includes thorax; performed <2 min at bedside; detects hemopneumothorax, pericardial tamponade, free peritoneal fluid
• Whole Body CT (WBCT/pan-scan): CT chest-abdomen-pelvis with CTA; single-stop imaging; increases 30-day survival (REACT-2 trial evidence emerging); "Trauma CT" = within 30 minutes of arrival
• Point-of-Care Ultrasound (POCUS): Pneumothorax, IVC, cardiac function at bedside
• CT angiography: Identify vascular injury, guide embolization

• REBOA (Resuscitative Endovascular Balloon Occlusion of Aorta): Zone I (thoracic aorta) for subdiaphragmatic hemorrhage; Zone III (infrarenal) for pelvic fractures
  • Advantage: Temporizing measure, no thoracotomy
  • Current evidence: AAST prospective study - non-inferior to EDT for select patients
• Pelvic angioembolization: For arterial pelvic bleeding (CT evidence + hemodynamic instability after pelvic binder/sheet)
• CRAO (Catheter-directed resuscitative aortic occlusion): Similar to REBOA
• Pre-peritoneal pelvic packing (PPP): For venous pelvic hemorrhage; in combination with pelvic external fixation
• Zone 3 REBOA + PPP combination for unstable pelvic fractures (replaces emergent laparotomy in many centres)

• Hybrid OR: Combined interventional radiology + OR capabilities; simultaneous angioembolization and orthopedic stabilization
• Endovascular repair: TEVAR for aortic disruption vs open repair
• Damage Control Surgery (DCS): Abbreviated laparotomy, temporary abdominal closure, ICU resuscitation, planned re-look in 24-48h

• Permissive hypercapnia in ARDS
• Prone positioning for severe ARDS (PROSEVA trial - 28-day mortality reduction)
• Lung protective ventilation: Tidal volume 6 mL/kg IBW
• VTE prophylaxis: Inferior vena cava filter for high-risk patients unable to receive anticoagulation (TBI, spinal cord injury); early low-molecular-weight heparin when safe
• Nutrition: Early enteral nutrition within 24-48h

• ISS, NISS (New ISS), RTS, TRISS for triage and prognostication
• RISC II: Revised Injury Severity Classification - better mortality prediction
• Serum lactate + base deficit: Best resuscitation endpoints
• Near-infrared spectroscopy (NIRS): Non-invasive regional tissue oxygenation monitoring

• Hemostatic dressings: QuikClot (kaolin), XSTAT (cellulose sponge), HemCon (chitosan) for junctional/compressible hemorrhage
• Wound ballistics management: Military trauma lessons applied to civilian care
• Tourniquets (CAT): Extremity hemorrhage - apply before hospital arrival

• Fracture table-free lateral femoral nailing: Reduces positioning time
• Suprapatella nailing (tibial): Avoids peroneal nerve; quicker in polytrauma
• Intraoperative CT/navigation: Improves accuracy, reduces re-do
• Negative pressure wound therapy (NPWT): Bridge to definitive closure in contaminated/swollen wounds
• Vascular injury protocols: Vascular surgery availability 24/7; shunting (Sundt/Javid) for limb-threatening ischemia as damage control

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Quick Reference Index