• Knee arthroscopy can be performed safely on an outpatient basis with general, spinal, regional, or local anesthesia.

• Preoperative antibiotics are commonly administered but have not been shown to be more effective than no antibiotics at preventing infection after uncomplicated knee arthroscopy.¹

• A recent randomized controlled study showed no benefit when chemoprophylaxis was used to prevent thromboembolic events in otherwise healthy patients.²

• Although basic science studies have demonstrated deleterious effects of local anesthetics on cartilage in vitro, human studies have failed to recreate these findings.³ Intra-articular or portal site injections of local anesthetics, epinephrine, opioids, and nonsteroidal anti-inflammatory drugs before or after arthroscopy are effective analgesic and hemostatic adjuvants.⁴ Preoperative portal site injections can help verify correct portal placement when patients are obese or have difficult anatomy.

• 4.0-mm arthroscope with 30-degree lens and light source (Fig. 33-1)

• A 70-degree lens should be available if posterior compartment pathology or instrumentation is expected.

• Inflow through the camera obturator can improve visualization directly adjacent to the camera lens by increasing fluid pressures in the immediate vicinity.

• Arthroscopy fluid

• Lactated Ringer or normal saline

▪ Adding diluted epinephrine can improve visualization (1 mg/L).⁵

• Fluid management

▪ Most contemporary pumps can independently control fluid pressures and flow rates, aiding in visualization. Pressures between 40 and 80 mm Hg are commonly used for knee arthroscopy.

▪ Arthroscopic fluid bags can alternatively be suspended above the field to use gravity to generate positive intra-articular fluid pressures. Less equipment is necessary, but pressures and flows may be too low or too inconsistent for optimal visualization.

▪ Outflow or suction can either be attached to the camera obturator or through a separate obturator placed in the superomedial or superolateral portals. Use of a separate outflow cannula can aid in visualization by clearing blood and debris away from the camera.

• Tourniquet

• The tourniquet is not routinely inflated, though it is commonly placed on the patient. While its use has deleterious effects on muscle function and physiology, short-term use during knee arthroscopy does not seem to impact outcomes.⁶

• Motorized shaver with suction

• Instruments

• Scalpel

• Arthroscopic probe

• Arthroscopic punches or biters

• Supine

• Patient may either have both legs supported by the bed or positioned so that the knees bend freely over a break in the bed.

▪ While dropping the end of the bed offers better access to the posterior compartments and better control over the operative leg, this requires additional steps before surgery and care must be taken to flex the nonoperative leg at the hip to avoid a femoral nerve traction palsy.

• A lateral post or leg holder should be used to provide a fulcrum for opening the medial or lateral compartments (Fig. 33-2).

• The tibiofemoral joint line, inferior pole of the patella, and patella tendon are important landmarks for portal site identification (Fig. 33-3).

• The anteromedial and anterolateral are the two most commonly used portals. They are the only portals necessary for many procedures. These are located at the soft spots just medially and laterally to the patellar tendon ˜1 cm above the level of the joint line and below the level of the inferior patellar pole.

• Skin incisions are ˜1 cm and can be vertical, which allows easy extension for removal of large objects or creation of formal arthrotomies, or horizontal, which are more cosmetic and have a lower chance of saphenous nerve injury.

• Superomedial and superolateral portals are commonly used for an outflow portal or to assess patellofemoral pathology. While the use of an independent outflow portal can improve visualization and fluid management, superomedial portals have been associated with quadriceps muscle dysfunction postoperatively. These portals are placed several centimeters proximal to the patella and either medial or lateral to the quadriceps tendon.⁷