Introduction
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The knee was the first joint to be examined arthroscopically and many of the fundamental principles for arthroscopy were originally developed for the knee.
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First knee arthroscopy was performed in Europe.
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Japanese surgeons (Takagi and Watanabe) significantly advanced the field.
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North American surgeons did not embrace knee arthroscopy until the 1960s (Jackson, O’Connor, Casscells, McGinty)
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Knee arthroscopy quickly progressed from a diagnostic to a therapeutic modality.
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Like any joint, a systematic evaluation of the entire knee should precede treatment. Documentation, including images of all pathology and treatment thereof, should be kept in the patient’s medical records.
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Indications
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Synovitis
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Meniscal tear
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Septic knee joint
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Anterior cruciate ligament tear
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Mild-to-moderate knee arthritis with mechanical symptoms.
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Focal chondral defect
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Loose bodies
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Failure of conservative treatment with continued knee pain that affects patient activity.
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Common procedures performed include
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Diagnostic arthroscopy
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Synovectomy
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Loose body removal
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Partial meniscectomy
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Meniscus repair
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Loose body removal
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Chondroplasty
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Microfracture
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Osteochondral plug transfer
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Autologous chondrocyte implantation
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Anterior cruciate ligament reconstruction
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Contraindications to knee arthroscopy include
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Local skin infection over portal site
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Patients who are expected to be noncompliant with postoperative rehabilitation
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Preoperative Considerations
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A thorough medical evaluation, to include a complete history and physical examination and review of symptoms, should be reviewed before performing arthroscopy.
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Preoperative consultation with appropriate primary care/medical specialists and anesthesia will help reduce perioperative problems.
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Postoperative deep vein thrombosis (DVT) prophylaxis should be considered for patients with several risk factors (smokers, older patients, females on birth control pills, patients with known history of DVT, obese patients, etc.)
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Review all medical records and sign your site!
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Anesthetic options include local, regional, and general anesthesia, or some combination thereof.
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Local anesthesia alone is best suited for short, simple procedures such as loose body removal. More extensive procedures and stressing the knee to evaluate compartments are poorly tolerated.
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Regional anesthesia including spinal, epidural and selective nerve blocks can be useful alone or in combination with general anesthesia for prolonged postoperative pain relief (e.g., outpatient anterior cruciate ligament [ACL] surgery).
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General anesthesia is favored for the majority of patients. It allows for complete exposure, muscle relaxation, and obviates any problems with tourniquet pain.
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Examination under anesthesia (EUA)
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Best performed before placing the leg into a leg holder
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Systematic physical examination should be performed.
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Positioning ( Fig. 2-1 )
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The patient is placed supine. A commercially available leg holder or post is used to stabilize the thigh during examination under anesthesia.
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Nonoperative leg should be padded and protected.
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Standard prep and drape is accomplished.
Figure 2-1
The patient is positioned supine with the use of a leg holder or lateral post.
(From Miller MD, Chhabra AB, Hurwitz S, et al. [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008, p 483.)
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Equipment
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Arthroscope
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30-degree scope most commonly used but 70-degree scope can be helpful for areas that may be otherwise difficult to see (e.g., posterior corners).
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Arthroscopic probe
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Allows the surgeon the “sense of touch”
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Hand-held instruments
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Up-going instruments best for medial compartment
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Straight instruments more useful in lateral compartment
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Right and left angled instruments often helpful in contouring menisci.
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Motorized instruments
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Helpful for removing debris and contouring
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Larger (5.5 mm) shavers best for synovium/central areas
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Smaller (4.5 mm) shavers best in the compartments (avoid chondral injury)
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Relevant Anatomy ( Fig. 2-2 )
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Patella
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Thickest articular cartilage
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Articulates with the femoral trochlea
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Fully engages at 30- to 40-degrees of knee flexion
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Figure 2-2
The anatomy of the knee joint.
(From Miller MD, Chhabra AB, Hurwitz S, et al. [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008, p 428.)
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Distal Femur
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Sulcus terminalis lateral
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Medial condyle is larger than the lateral condyle.
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Lateral condyle is longer but narrower.
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Proximal Tibia
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Cruciates central
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Insert between tibial spines.
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The ACL is more anterior and inserts on the lateral femoral condyle.
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The posterior cruciate ligament (PCL) originates posteriorly, below the articular surface, and inserts on the medial femoral condyle.
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Medial tibial plateau is longer in sagittal plane and is concave.
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Lateral tibial plateau is convex in the sagittal plane.
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Menisci cover the tibial plateaus.
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Medial meniscus is more “C-shaped” and insertions are far apart.
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Lateral meniscus is more semicircular and insertions are adjacent to the ACL.
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Portal Placement ( Fig. 2-3 )
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Inferolateral portal
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Just lateral to patellar tendon and just above the joint line
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Primary viewing portal
Figure 2-3
Portal placement for knee arthroscopy.
(From Miller MD, Chhabra AB, Hurwitz S, et al. [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008, p 485.)
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Inferomedial portal
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Just medial to the patellar tendon and just above the joint line
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Usually easier to palpate and lateral portal location can be based on this portal.
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Primary instrument portal
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Can be used for visualization based on access
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Superior portals
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Created above the level of the patella
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Lateral favored (does not disrupt the vastus medialis obliquus)
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Can be used to observe patellar tracking
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Posteromedial portal
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Just posterior to the medial collateral ligament (MCL), above the joint line
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Localized with spinal needle
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Avoid saphenous nerve/vein (nick and spread)
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Used for viewing posterior horn medial meniscus, loose body removal, complete synovectomy
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Posterolateral portal
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Just posterior to the lateral collateral ligament (LCL) but anterior to biceps, above joint line
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Localized with spinal needle
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Avoid peroneal nerve (posterior to biceps)
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Used for viewing posterior horn of lateral meniscus, loose body removal, complete synovectomy.
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Additional portals (e.g., posterior portals)
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As needed
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Useful for extensive synovectomies
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Diagnostic Arthroscopy ( Fig. 2-4 )
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Scope insertion
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The anterolateral portal is made with an 11-blade (sharp edge superior) and the capsule is incised by aiming toward the femoral notch.
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The scope cannula with blunt obturator is inserted into the inferolateral portal and directed up into the suprapatellar pouch by extending the knee and “bouncing” off the medial femoral condyle—do not force the obturator!
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The final position can be confirmed by sweeping the obturator back and forth.
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The anteromedial portal can be made at the outset of the case, or it can be localized under direct visualization with a spinal needle.
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The obturator is removed and the scope is inserted into the cannula.
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The scope is held with the camera cord down, facing the foot and the light cord is rotated to change the direction of viewing.
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