Diagnostic Arthroscopy

Diagnostic Arthroscopy - Joint Peep Show

• Definition: Minimally invasive surgical (MIS) procedure to visualize, diagnose, & sometimes treat joint problems.
• Purpose: Direct internal inspection of a joint using an arthroscope (a small camera).
• Advantages:
  • Minimally invasive: Smaller incisions, ↓ pain, faster recovery vs. open surgery.
  • High diagnostic accuracy: Superior visualization of structures.
  • Allows for biopsy & minor therapeutic interventions simultaneously.
• General Indications (common):
  • Knee: Meniscal tears, ACL/PCL injuries, cartilage damage, loose bodies.
  • Shoulder: Rotator cuff tears, impingement syndrome, labral tears, instability.

⭐ Arthroscopy allows direct visualization and dynamic assessment of intra-articular structures.

Portals & Setup - Keyhole Commute

Triangulation principle: Key for 'keyhole' surgery; scope in one portal (e.g., standard 30° arthroscope), instruments in others. Patient Positioning: Supine (Knee); Lateral decubitus or Beach chair (Shoulder). Anaesthesia: General, regional (spinal/epidural), or local.

• Knee Portals (Standard):
  • Anterolateral (AL): Primary viewing.
  • Anteromedial (AM): Primary working.
  • Superolateral (SL): Outflow, accessory instrumentation.
• Shoulder Portals (Standard):
  • Posterior: Primary viewing.
  • Anterior: Primary working.

⭐ The anterolateral portal is often the initial viewing portal for knee arthroscopy.

Instrumentation - Scope & Probe Parade

• Arthroscope: Viewing tool; rod-lens/fiber optics. Angles: 30° (workhorse), 70° (posterior).
• Light Source: Xenon/LED for bright illumination.
• Camera & Monitor: HD camera to monitor display.
• Irrigation System: Fluid (saline) for distension, clarity; pressure control.
• Hand Instruments:
  • Probe: Tactile feedback, assess tissue.
  • Grasper: Manipulate/retrieve tissue/loose bodies.
  • Biopsy Forceps: Tissue sampling.
• Shaver: Motorized debridement (mainly therapeutic).

⭐ A 30° arthroscope is the workhorse for most diagnostic procedures.

Common Findings - Lesion Lookout

Systematic intra-articular examination is key.

• Knee:
  • Meniscal tears (types: radial, longitudinal, bucket-handle, flap, complex)
  • Ligament: ACL, PCL injuries
  • Chondral damage (Outerbridge classification)
  • Synovitis, loose bodies
• Shoulder:
  • Rotator cuff tears (partial/full)
  • Labral lesions: Bankart, SLAP
  • Impingement signs
  • Biceps tendon pathology
• Documentation: Images/video vital.

📌 Outerbridge Grades: Softening (I), Small frags <1.5cm (II), Large frags >1.5cm (III), Bone exposed (IV).

⭐ The Outerbridge classification is commonly used to grade articular cartilage damage observed during arthroscopy.

Complications & Contraindications - Cautionary Tales

• Complications: 📌 Mnemonic: I Never Drink Sour Milk (Infection, Neurovascular injury, DVT, Stiffness/Adhesions, Material failure).
  • Other key risks: Fluid extravasation (→ Compartment syndrome ⚠️), Haemarthrosis.
• Contraindications:
  • Absolute: Active sepsis (e.g., joint infection).
  • Relative: Severe uncontrolled medical comorbidities, active skin lesions over portal sites.

⭐ Fluid extravasation leading to compartment syndrome is a rare but serious complication, especially in prolonged procedures or with high pump pressures.

High‑Yield Points - ⚡ Biggest Takeaways

• Minimally invasive technique for direct intra-articular visualization.
• Gold standard for diagnosing meniscal tears, ligament injuries (ACL/PCL), and cartilage damage.
• Allows precise biopsy and synovial fluid analysis under direct vision.
• Commonly performed on knee, shoulder, hip, ankle, and wrist joints.
• Potential complications: Infection, hemarthrosis, nerve injury, DVT (though rare).
• Key contraindications: Active joint/skin infection, severe arthrofibrosis.
• Superior to MRI for certain subtle chondral lesions and dynamic joint assessment.