Preparation for Knee Arthroscopy : Wheeless' Textbook of Orthopaedics

- See: Knee Joint Menu

- Patient Positioning and Preparation:
- positioning:
- opposite limb is well padded to prevent potential pressure problems;
- operative thigh is placed against an arthroscopy post or is placed in a circular thigh immobilizer;
- it is essential that the surgeon position the patient so that there is no difficulty in applying a valgus force to the knee while it remains in full extension (ie it does not move into flexion);
- without proper positioning, the knee will buckle into flexion as a valgus force is applied, and visualization of the posterior horn of the medial meniscus will be difficult;
- end of table may be dropped so that both limbs will dangle at 90 deg;
- tourniquet:
- generally a tourniquet is not necessary for routine knee arthroscopy, but its application is often useful when a hypertrophic fat pad requires debridement (such for management of chondral injuries);
- references:
- Postmeniscectomy tourniquet palsy and functional sequelae.
- Muscle rehabilitation after arthroscopic meniscectomy with or without tourniquet control. A preliminary randomized study.
- Effect of tourniquet ischaemia on muscle energy metabolism in meniscectomy patients.
- anesthesia:
- local anesthesia:
- indicated if only a simple arthroscopy is planned in a relatively thin patient;
- in obese patients w/ large thighs, local injection may further obscure the knee joint landmarks and may interfere with precise portal placement;
- consists of 30-50 ml of 1% lidocaine and 0.25% bupivacaine w/ epinephrine which is given under sterile conditions before the patient is prepped;
- the majority of the cocktail is given intra-articularly and about 6 cc is saved for the portals;
- it is essential to avoid injection into the deep subcutaneous tissue and the fat pad since this will cause the fat pad to swell and will interfere with visualization during the case;
- the majority of the local anesthetic is injected into the joint at a point well above the fat pad;
- the sudden "swoosh" of fluid into the joint confirms that the needle lies in the joint (and not fat pad);
- postoperative anesthesia:
- intra-articular narcotics: consider use of 5 cc of morphine prior to and at the end of surgery;
- IM Nsaids: consider IM Toradol;
- references:
- Intraarticular bupivacaine (Marcaine) after arthroscopic meniscectomy: a randomized double-blind controlled study.
                 - Knee arthroscopy using local anesthesia.
                 - Safety and efficacy of intra-articular bupivacaine and epinephrine anesthesia for knee arthroscopy.
                 - Outpatient arthroscopy of the knee under local anesthesia.
    - inflow:
- may either use gravity system or the more preferred pump inflow system;
- if a pump inflow system is used be aware excessive inflow pressure may lead to fluid extravasation if there is a concomitant capsular tear;
- this can be partially prevented by applying a firm coband wrap around the leg and calf, which will resist extravasation of fluid