Knee Arthroscopy

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Knee Arthroscopy - Scope Basics & Whys

Minimally invasive surgery (MIS) using an arthroscope (camera) and instruments to diagnose/treat intra-articular knee conditions.

  • Advantages:
    • Diagnostic: Superior direct visualization.
    • Therapeutic: Reduced pain, faster recovery, smaller incisions, ↓ infection risk vs open surgery.
  • General Indications:
    • Meniscal injuries: Tears (repair, partial meniscectomy).
    • Ligamentous injuries: ACL/PCL reconstruction.
    • Chondral defects: Articular cartilage lesions, OCD.
    • Synovial pathology: Synovitis, plica removal, biopsy.
    • Loose bodies: Cartilage/bone fragment removal.
    • Patellar disorders: Maltracking, instability.
    • Intra-articular fractures: Assessment/reduction (e.g., tibial plateau).
  • Key Contraindications:
    • Active infection (local/systemic).
    • Severe diffuse Osteoarthritis (limited benefit for pain).
    • Medical instability, uncorrected coagulopathy.

Knee Arthroscopy Setup and Patient Positioning

⭐ The most common indication for knee arthroscopy is a meniscal tear.

Knee Arthroscopy - Navigating Entryways

Knee Arthroscopy Portals and Neurovascular Structures

Standard portals provide access while minimizing neurovascular injury. 'Safe zones' are key.

  • Portal Placement Strategy:
    • Viewing portal: Usually Anterolateral (AL).
    • Working portal: Typically Anteromedial (AM).
    • Outflow: Superolateral (SL) is common.
PortalPrimary UseStructures at RiskSafe Zone
Anterolateral (AL)ViewingLateral Meniscus, Infrapatellar br. Saphenous N.1cm lateral to patellar tendon, 1cm above joint line
Anteromedial (AM)WorkingMedial Meniscus, Infrapatellar br. Saphenous N.1cm medial to patellar tendon, 1cm above joint line
Superolateral (SL)Outflow, InflowQuadriceps tendonSuperior & lateral to patella
Superomedial (SM)Inflow (optional)Quadriceps tendonSuperior & medial to patella
Posteromedial (PM)Loose bodies, PCLSaphenous N., Medial Femoral CondyleSoft spot post. to MCL, ant. to Medial Gastroc.
Posterolateral (PL)Loose bodies, PCLCommon Peroneal N., Popliteal vesselsSoft spot post. to LCL, ant. to Biceps Femoris

⭐ The anterolateral portal is typically the first portal made, established under direct vision after insufflation or by 'feel' relative to anatomical landmarks like the inferior pole of the patella and the lateral edge of the patellar tendon.

Understanding these entryways and their associated risks is crucial for safe and effective knee arthroscopy. Always palpate landmarks and consider patient anatomy variability.

Knee Arthroscopy - Scope & Fixes

  • Meniscal Procedures:

    • Meniscectomy: Partial (preferred, preserves rim) or Total (complex, irreparable avascular tears).
    • Meniscal Repair: For young (<40y), active patients; peripheral (vascular zone, e.g. red-red), acute (<6-8 wks) longitudinal/bucket-handle tears. Techniques: all-inside, inside-out, outside-in. | | Meniscectomy (Partial) | Meniscal Repair | |-----------------|-------------------------------|-------------------------------------| | Tear Type | Complex, degenerative, radial | Longitudinal, bucket-handle (vascular)| | Patient | Older, low demand | Younger (<40y), active, acute | | Goal | Rapid symptom relief | Preserve meniscus, ↓OA risk |
  • Ligament Reconstruction (ACL/PCL):

    • Graft Choices: Autograft (BPTB, Hamstring); Allograft (cadaveric, revisions).

    ⭐ Bone-patellar tendon-bone (BPTB) autograft is often considered a gold standard for ACL reconstruction in high-demand athletes. Arthroscopic view of ACL reconstruction with BPTB graft

  • Cartilage Procedures:

    • Chondroplasty: Smoothing fibrillated cartilage.
    • Microfracture: For defects < 2-4 cm² (younger pts); promotes fibrocartilage. Microfracture treatment of chondral defect
  • Other Common Procedures:

    • Loose Body Removal: Symptomatic fragments (OCD, trauma, chondromatosis).
    • Synovectomy: Inflamed synovium (RA, PVNS).

Knee Arthroscopy - Pitfalls & Bounce-back

Common Complications & Management Hints:

ComplicationKey Points / Management Hint
Intra-operative
Neurovascular Injury (Saphenous, Peroneal)Careful portal placement; observe
Instrument BreakagePre-op check; retrieve immediately
Fluid Extravasation/ ⚠️ Compartment SyndromeMonitor inflow/outflow; urgent fasciotomy if CS
Tourniquet IssuesLimit time/pressure; monitor
Post-operative
Infection (Septic Arthritis)Asepsis; antibiotics, washout if needed
DVT/PEEarly mobilization; prophylaxis (high-risk)
HemarthrosisMeticulous hemostasis; aspiration if tense
Stiffness/ArthrofibrosisEarly ROM; physiotherapy, MUA/arthrolysis
CRPSEarly mobilization; multimodal pain management

Bounce-back (Rehab Principles):

  • RICE: Rest, Ice, Compression, Elevation
  • Early ROM (Range of Motion)
  • Progressive strengthening

High‑Yield Points - ⚡ Biggest Takeaways

  • Meniscal tears, especially bucket-handle tears, are the most common indication for knee arthroscopy.
  • It serves as both a diagnostic tool and a therapeutic procedure, allowing direct visualization and treatment.
  • Standard portals include anterolateral (AL) and anteromedial (AM); accessory portals are used as needed.
  • Key complications include saphenous nerve injury (particularly with the AM portal), infection, DVT, and instrument breakage.
  • Major contraindications are active local infection and severe osteoarthritis where arthroplasty is more appropriate.
  • It is the standard approach for ACL reconstruction (graft placement) and effective for loose body removal.

Practice Questions: Knee Arthroscopy

Test your understanding with these related questions

In meniscus injury, 'Locking'-that is sudden inability to extend the knee fully is a feature of:

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Flashcards: Knee Arthroscopy

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Delayed effusion of synovial fluid in medial meniscal tear leads to _____ sign on knee examination

TAP TO REVEAL ANSWER

Delayed effusion of synovial fluid in medial meniscal tear leads to _____ sign on knee examination

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