Knee Arthroscopy / ACL Reconstruction

Patient phenotype

Younger (20s-40s) athletic injury most common; older for meniscal repair. Otherwise healthy mostly. Outpatient.

Procedure

2-3 portal arthroscopic. Tourniquet on thigh (250-300 mmHg). Saline irrigation. ACL: graft harvest (BTB or hamstring) + tunnel drilling + graft fixation. ~1-2 hours.

Anesthetic plan

Spinal vs GA + femoral or adductor canal block. Adductor canal block preferred over femoral (preserves quadriceps strength for early ambulation). Multimodal: acetaminophen, NSAID, ice. Outpatient discharge same day.

Setup

·Standard monitors
·1 PIV
·Spinal kit if neuraxial chosen
·Adductor canal block kit + US
·Tourniquet — verify pressure + time
·Forced air warmer

Biggest concerns by phase

Pre-op

Adductor canal vs femoral block

Adductor canal: motor-sparing (saphenous nerve only) — quad strength preserved → ambulation + falls reduced. Femoral: stronger analgesia but quad weakness → falls. Modern preference: adductor canal + IPACK (popliteal) for posterior knee pain.

Intra-op

Tourniquet management

Limb exsanguinated, tourniquet 250-300 mmHg. Document time (limit ≤ 2h, ideally < 1.5h). Tourniquet pain: HTN, tachycardia after 45-60 min even under GA — deepen anesthesia or release/redo.

Intra-op

Tourniquet release physiology

Release → reactive hyperemia, hyperkalemia, lactic acid washout, transient hypotension. Usually well-tolerated; significant in long tourniquet times or comorbidities.

Intra-op

Fluid extravasation

Saline irrigation can extravasate into thigh/leg → compartment syndrome (rare). Watch for swelling beyond joint. Pump pressure monitoring.

Emergence

PONV prophylaxis + outpatient discharge

Multimodal antiemetic. Multimodal analgesia for opioid-sparing discharge. Verify block before leaving (foot dorsiflexion to ensure peroneal nerve intact).

Mock-defense scenarios

Practice answering these out loud. The probes show what an examiner is listening for.

22-yo M, recreational soccer, ACL tear + meniscus. Outpatient ACL reconstruction with hamstring autograft. Walk through anesthetic plan.

What an examiner probes for

▹Spinal vs GA + adductor canal block (latter preferred for ambulation)
▹Multimodal opioid-sparing
▹Tourniquet time + management
▹PONV prevention
▹Discharge criteria

Sources

Miller's Ch 56
ASRA Adductor Canal Review

Anatomy reference

Sourced reference images. 4 matches for "knee joint femur tibia".

OpenStax · CC BY 4.0

OpenStax · CC BY 4.0

OpenStax · CC BY 4.0

Wikimedia · Public domain

Browse the full image library →

Education only — anesthetic plans vary by patient, institution, and provider judgment. Use as a starting point, not a substitute for clinical reasoning.