Section I. Knee arthroscopy Arthroscopy is most often used for the diagnosis and surgery of knee disorders. Arthroscopic techniques are extremely valuable in the diagnosis and treatment of intra-articular pathology. Arthroscopy is used to assess the accuracy of clinical examinations, laboratory tests, x-rays, MRI, and other diagnostic methods for knee disorders.Johnson compared clinical impressions with postoperative diagnoses and found that a large proportion of patients had many other diagnoses added, some of which were completely different from the clinical impression. Of the 229 patients with what was thought to be a medial meniscal tear, only 21% had an arthroscopic confirmation of only a medial meniscal tear, 23% had a combination of other diagnoses, and 56% had a completely different diagnosis. A missed lateral meniscus tear was found in 5% of knees diagnosed with a medial meniscus tear. Curran and Woodward analyzed 396 knee arthroscopy cases and found that the overall clinical diagnostic accuracy was only 71%. Noyes et al. reported that 72% of knees arthroscopically examined for acute traumatic intra-articular hemorrhage had varying degrees of ACL injury, and many of these knees had negative or suspicious positive stress tests. high incidence of ACL tears and other intra-articular disorders in patients who underwent early arthroscopic evaluation for traumatic intra-articular hemorrhage. Arthroscopy should be considered an adjunctive diagnostic tool and should be used in conjunction with a detailed history, thorough physical examination, and reasonable radiography. It should only be used as an adjunct to clinical examination and not as a substitute for a full clinical examination. With increasing proficiency in the examination of the limb and the use of more accurate ancillary examinations, including MRI, we rarely perform a purely “diagnostic arthroscopy”, but rather explain the various possible surgical options to the patient prior to the examination, and perform the final surgical treatment in conjunction with a thorough arthroscopic examination. The basic principles, equipment, indications, contraindications and complications of arthroscopy are described below. I. Basic Diagnostic Techniques (a) General Rules Simple diagnostic knee arthroscopy may be performed before arthroscopic surgery or before arthrocentesis. Local anesthesia, spinal anesthesia, or general anesthesia are acceptable. If used for diagnostic purposes only, local anesthesia may be used if the patient is cooperative, especially if the operator has skilled arthroscopic technique. If diagnostic arthroscopy is to be followed by arthrocentesis or intra-articular surgery, general anesthesia should be used unless contraindicated. When spinal anesthesia is chosen, a tourniquet may be unbearable for the patient if the procedure takes longer (more than 1 hour). Therefore, unless there are specific contraindications, general anesthesia is preferable, especially for inexperienced surgeons. Arthroscopic surgery should be performed in the operating room under strictly sterile conditions. The rigor of this procedure should not be taken lightly. Although complications such as infection are rare, carelessness in scrubbing, disinfection, sheeting, or in the use of irrigation solutions, arthroscopes and instruments can lead to intra-articular infection, which can cause the same damage as arthrocentesis. Sterility of arthroscopic equipment and the use of waterproof arthroscopic gowns and waterproof large sheets are key. Closing off the distal and proximal limbs of the arthroscopic area and covering the area with a skin wrap (Dura Prep) or with an iodine-impregnated sheet can reduce the chance of infection. The hand washing nurse uses a large table for instruments. The table is placed at a site that is convenient for her to use, usually on the same side as the surgical knee. A Mayo rack is placed above the patient’s upper thigh on the operating table and commonly used instruments are placed on the rack. The electrical and optical cables are connected to the appropriate electrical (optical) source and placed on the side table. The irrigation bag is suspended from the infusion rack on the head side of the table, 4 to 5 feet above the patient. An arthroscopic pump is used to keep the irrigation fluid flowing through the arthroscopic cannula or a separate cannula unobstructed and to maintain a constant pressure. The use of this pump eliminates the need for a tourniquet so that the procedure can be performed under local anesthesia, and physicians who advocate the use of this pump claim that it reduces the amount of irrigation fluid used because the pressure receptor keeps the flow within the limits necessary for joint expansion. A tourniquet is tied around the thigh but is not inflated during diagnostic arthroscopy unless bleeding prevents visualization. Inflation of the tourniquet can cause the synovium and other vascularized tissues to turn white, making diagnosis difficult. The vascular distribution and potential for healing of the meniscus should be evaluated without tourniquet inflation and with low intra-articular hydrostatic pressure. In cases of acute trauma or when the surgeon anticipates more complex intra-articular surgery, the tourniquet may be inflated after expulsion of blood. Stress is applied to the knee joint to open the different compartments for both diagnostic and therapeutic manipulations, either by an assistant, a padded lateral post, or a commercially available lower extremity immobilization brace. Compression by an assistant is associated with problems of fatigue and uneven force, which is the least effective method. A padded lateral post fixed to the edge of the operating table applies effective valgus stress when the knee is in extension or near extension, but does not control rotation. The commercially available thigh brace is the most effective, but it must be remembered that it has some potential dangers. When using lower extremity braces in order to easily apply pressure and open the joint compartment, especially the posterior lateral compartment, to some extent these devices can prevent manipulation within the patellofemoral joint via the superior portal, and one must be aware of the potential tourniquet effect of thigh braces, which can lead to fractures due to excessive stress in osteoporotic individuals whose limbs are firmly immobilized. We have had no problems with the lower extremity fixation brace, and we believe that the advantages of its ability to control the joint and apply pressure far outweigh its disadvantages. Figure 48-1 Commercially available lower extremity immobilization frame fixed to the side beam of a standard operating table with a balloon tourniquet placed inside this frame. (b) After successful postural anesthesia, the tourniquet and lower extremity immobilization frame are placed if needed, and the limb from the ankle to the tourniquet is thoroughly brushed and disinfected in the same manner as for arthrotomy. Very good commercially available sterile wipes are available with the arthroscope, with which the foot and lower leg and the distal portion of the thigh below the tourniquet and immobilization frame can be freestanding. The operator and assistant are also provided with waterproof surgical gowns to prevent contamination. The waterproof sheet and the central rubber opening isolate the unsterile proximal thigh from the operative field. The patient is placed in the supine position with the sterile wrapped limb placed at an angle to the outside of the operating table. When using a lower extremity immobilization frame or lateral post, the surgeon can stand on the medial side of the abducted leg and place the patient’s foot and ankle at the surgeon’s hip and iliac crest; the surgeon’s lateral foot will step on a footstool, which will help maintain the correct position of the patient’s foot (Figure 48-3). This position frees the surgeon’s hands and allows the surgeon to externalize the leg by simply tilting the patient’s leg slightly within the leg brace. This maneuver opens the medial compartment for examination and exploration. When the patient is supine, an assistant is required to maintain the affected limb in a figure of four if the lateral compartment is examined. A, a platform procedure in which the surgeon and assistant stand at the operating table. b, a folding table procedure in which the surgeon sits and places the patient’s calf and foot, wrapped in a sterile sheet, on the surgeon’s knee. c, the surgeon should wear a waterproof sterile gown that wraps around the waist and extends to the distal calf. d, with the use of a lower extremity immobilization brace, the surgeon usually stands on the medial side of the patient’s abducted lower extremity, with the lateral leg on a small footstool, and places the patient’s ankle on the the surgeon’s hip and iliac crest area. The patient may also lie supine on a standard operating table with the knee located slightly distal to the distal fold of the table. The foot of the bed is lowered and both lower extremities are lowered at 90° (Figure 48-4). The contralateral limb should be padded to prevent compression. Flex the middle of the bed to flex the hip joint to eliminate strain on the femoral nerve and to level the lumbar spine. Some physicians advocate wrapping the healthy limb to reduce venous depression. The healthy limb may also be secured to a brace. After lowering the foot of the bed, the physician can apply pressure to the affected limb with his or her own body to open the medial and lateral compartments of the joint. The surgeon stands on the medial side of the affected limb and places the patient’s foot and ankle on his or her hip and iliac crest area, applying external rotation pressure to open the medial compartment, changing position, standing on the lateral side of the affected limb and placing the patient’s foot on the surgeon’s hip and iliac crest area, and applying internal rotation pressure to open the lateral compartment. A, Install a lateral strut on the table and pad with a sandbag, which allows easier positioning of the affected limb and enables full range of motion in ligament reconstruction. b, When operating with a folding table, it is best to flex the hip and pad. The use of an elastic bandage or lower extremity immobilization brace may prevent venous stasis.