Complications of Arthroplasty

Complications of Arthroplasty

Complications of Arthroplasty

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PJI - Septic Sabotage

  • Infection of prosthetic joint & periprosthetic tissues; biofilm formation is key.
  • Classification by Onset:
    • Early (<3 months): Acute symptoms; often S. aureus.
    • Delayed (3-12 months): Subtle; CoNS, P. acnes.
    • Late (>12 months): Hematogenous seeding.
  • Diagnosis: 📌 MSIS Criteria (2018 update).
    • Major Criteria (1 needed): Sinus tract OR 2+ positive cultures (same organism).
    • Minor Criteria (Score ≥6 for PJI):
      • Elevated ESR (>30mm/hr) & CRP (>10mg/L).
      • Synovial WBC >3000/µL or ++Leukocyte Esterase.
      • Synovial PMN% >80%.
      • Positive histology (>5 PMNs/HPF).
      • Single positive culture.
      • Elevated synovial Alpha-Defensin.
  • Management:
    • DAIR (Debridement, Antibiotics, Implant Retention): Early PJI, stable implant.
    • Exchange Arthroplasty: 1-stage or 2-stage (gold standard for chronic).

⭐ The Musculoskeletal Infection Society (MSIS) criteria are paramount for diagnosing PJI.

VTE & Bleeds - Clots & Crimson Tides

  • VTE (DVT/PE): Major risk post-arthroplasty. 📌 VIRCHOW's triad (Stasis, Hypercoagulability, Endothelial injury).
    • Prophylaxis: Crucial. Mechanical (Graduated Compression Stockings - GCS, Intermittent Pneumatic Compression - IPC) & Pharmacological: LMWH (e.g., Enoxaparin 40mg OD), DOACs (e.g., Rivaroxaban 10mg OD), Warfarin (target INR 2-3). Duration typically 10-35 days.
    • Diagnosis: DVT (Ultrasound Doppler), PE (CT Pulmonary Angiography - CTPA).
    • Management: Therapeutic anticoagulation.
  • Bleeding/Hematoma:
    • Risk factors: Anticoagulants, surgical technique, patient factors.
    • Signs: Localized swelling, pain, ecchymosis, wound drainage.
    • Management: Observation, compression dressing. Surgical evacuation if large, rapidly expanding, neurovascular compromise, or suspected infection. Tranexamic acid (TXA) use can ↓ blood loss.

⭐ Routine VTE prophylaxis is mandatory for lower limb arthroplasty unless contraindicated.

Mechanical Failures - Loose, Worn & Broken

  • Aseptic Loosening:
    • Most common late failure. Patho: Wear particle-induced osteolysis (macrophage activation → cytokines → osteoclasts).
    • X-ray: Progressive radiolucent lines >2mm at implant-bone/cement-bone interface. Zones: Gruen (femur), DeLee & Charnley (acetabulum).
  • Wear & Osteolysis ("Particle Disease"):
    • Particle generation (polyethylene, metal, ceramic, cement) is key.
    • Types of wear: Adhesive (most common), Abrasive (3rd body), Fatigue, Corrosive (metals).
    • Leads to periprosthetic bone loss.
  • Implant Fracture/Breakage:
    • Rare. Risk factors: ↑BMI, high activity, implant design/malposition.
    • Common sites: Femoral stem (esp. modular necks), tibial tray, polyethylene liner.

Gruen Zones of Osteolysis in Total Hip Arthroplasty

Wear Particle Types & Osteolysis

ParticleBiological Response & Osteolysis Pattern
PolyethyleneMacrophage activation (TNF-α, IL-1, IL-6); linear/expansile osteolysis. Most common.
Metal (Co-Cr)ALVAL (Aseptic Lymphocyte-dominated Vasculitis-Associated Lesion), pseudotumors (MoM); ↑ion levels.
CeramicBiologically inert, low wear. Osteolysis rare; if present, often due to 3rd body wear or liner fracture.
PMMA (Cement)Granulomatous reaction; can contribute to loosening if fragmented.

Neurovascular & HO - Zaps, Pipes & Extra Bone

  • Neurovascular Injury:
    • Nerve Palsy:
      • THR: Sciatic n. (esp. posterior approach), Femoral n.
      • TKR: Common Peroneal n. (most frequent), Tibial n., Saphenous n.
      • Risks: limb lengthening, direct trauma, pre-existing neuropathy.
    • Vascular Injury: Femoral/Popliteal arteries most common.
      • Signs: ↓ pulses, expanding hematoma, pallor.
      • Action: Immediate surgical repair.
  • Heterotopic Ossification (HO):
    • Pathological extra-articular bone.
    • Classified by Brooker Classification (Grade I-IV).
    • Prophylaxis: NSAIDs (e.g., Indomethacin), single low-dose radiation (700-800 cGy).
    • Treatment: Surgical excision for mature, symptomatic HO. Pelvic Quadrants and Neurovascular Structures at Risk

⭐ The common peroneal nerve is the most frequently injured nerve during Total Knee Arthroplasty, while the sciatic nerve is most at risk during posterior approach Total Hip Arthroplasty.

High‑Yield Points - ⚡ Biggest Takeaways

  • PJI (Periprosthetic Joint Infection): Most feared complication; Staph aureus is common. Diagnose with synovial fluid analysis.
  • Aseptic Loosening: Most common long-term reason for failure, resulting from polyethylene wear leading to osteolysis.
  • DVT/PE (Deep Vein Thrombosis/Pulmonary Embolism): Significant risk post-arthroplasty; early mobilization and prophylaxis are essential.
  • Dislocation: Frequent in THR (Total Hip Arthroplasty); risk factors include surgical approach and component positioning.
  • Periprosthetic Fractures: Classified by Vancouver classification (femur); can occur intra- or post-operatively.
  • Nerve Injury: Specific to joint (e.g., sciatic/common peroneal nerve in THR; axillary nerve in shoulder arthroplasty).

Practice Questions: Complications of Arthroplasty

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Complications of sling procedures (TVT) for USI are all except:

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Flashcards: Complications of Arthroplasty

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Patients with metal on metal implants have high levels of _____ and chromium in serum, erythrocytes, and urine.

TAP TO REVEAL ANSWER

Patients with metal on metal implants have high levels of _____ and chromium in serum, erythrocytes, and urine.

cobalt

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