Basics of Knee Arthroscopy

Few areas in orthopaedic surgery have grown as rapidly as knee arthroscopy. Arthroscopy often can be performed more quickly and with increased accuracy, lower complication rates, decreased hospitalization time, and shorter recovery periods compared with many more open operative techniques. The effective use of arthroscopy is based on the understanding of the benefits and indications for arthroscopy, as well as its limitations.

The knee was the first joint to be examined arthroscopically, and many of the fundamental principles of arthroscopy were developed for the knee. The first knee arthroscopy was performed in Europe and was advanced significantly by Japanese surgeons (Takagi and Watanabe). Applications continue to expand, and the future scope of arthroscopic applications is limited only by the imagination of the arthroscopist.

Preoperative Evaluation

Indications for knee arthroscopy continue to expand at a rapid rate. Each patient’s unique anatomy must be considered before initiating arthroscopy. Systematic evaluation of the entire knee includes a thorough physical examination and history. Additional studies including radiographs and advanced imaging should be reviewed, and proper documentation must be performed. Preoperative consultation with appropriate medical specialties and an anesthesiologist help reduce perioperative complications. Postoperative prophylaxis for deep vein thrombosis (DVT) should be considered in at-risk patients. Local, regional, and general anesthetic considerations should be reviewed with the patient and the anesthesia team.


Arthroscopy has diverse application in various forms of knee disease. Diagnostic arthroscopy helps confirm suspected knee injuries. An arthroscopic synovectomy can be useful for synovial biopsies to aid in the diagnosis of rheumatologic disorders, to remove diseased synovium and loose bodies, and to resect synovial folds or plicae. Arthroscopic treatment of septic arthritis of the knee has increased in frequency. Treatment of meniscal disease is perhaps the most common application of arthroscopy. Meniscal tears and repairs account for about half of knee injuries that require surgery. Osteochondral lesions commonly are addressed arthroscopically. Microfracture, autologous chondrocyte implantation, and osteochondral plug transfers are also performed arthroscopically.

Injuries to the cruciate ligaments can be diagnosed easily with arthroscopy and subsequently treated. Arthroscopic-assisted reconstruction of these ligaments is one of the most common orthopaedic procedures today. Other procedures that sometimes are aided with arthroscopy include tibial plateau fracture reduction, reduction and fixation of tibial eminence fractures, loose body removal, anterior fat pad debridement, and lateral release for patellar malalignment.

Contraindications for knee arthroscopy must be considered as well. One such consideration includes local skin infections over the portal sites. Additionally, alternative treatments should be considered for patients who have too high a risk for surgery and those who are not expected to be compliant with postoperative rehabilitation.


Two different forms of positioning are commonly used for knee arthroscopy. The patient can be positioned supine on the operating table, and a lateral post can be used for countertraction. Alternatively, the operative leg can be positioned in a commercially available leg holder ( Fig. 94-1 ). The operative leg is allowed to hang freely over the end of the operating table, and the opposite leg is positioned in a well-padded leg holder, taking care not to compress the peroneal nerve.


The patient is positioned supine with use of a leg holder on the lateral post.

(From Miller MD, Chhabra AB, Safran MR: Primer of arthroscopy, Philadelphia, 2010, Elsevier.)

Portal Placement

Landmarks, including the inferior pole of the patella and the joint line, are marked. Portal incisions are typically vertical, 1 cm in length, and made with a No. 11 blade while the knee is flexed. A spinal needle can be used for localization of the anteromedial portal ( Fig. 94-2 ). Portal placement is key to successful knee arthroscopy. Standard arthroscopic portals for knee arthroscopy have traditionally included a superomedial or superolateral portal for fluid inflow and outflow and inferomedial and inferolateral portals positioned just above the joint line on both sides of the patellar tendon for arthroscopy and instrumentation ( Fig. 94-3 ). Typically the inferolateral portal is used for arthroscopic visualization and the inferomedial portal is used for instrumentation, although alternating instrumentation between the medial and lateral portal is often necessary to reach certain structures ( Fig. 94-4 ). Newer arthroscopic fluid control systems have now made the use of superior outflow portals optional. The use of a far proximal superior portal can still be helpful for visualization of patellar tracking (see Fig. 94-3 ).


Anteromedial portal localization. A, The arthroscope is turned toward the anteromedial capsule. A spinal needle is inserted and positioned until it is just above the meniscus and its trajectory is satisfactory for intraarticular work. B, The spinal needle is carefully removed and a No. 15 or No. 11 blade is inserted blade-side up.


Portal placement for knee arthroscopy.

(From Miller MD, Chhabra AB, Safran MR: Primer of arthroscopy, Philadelphia, 2010, Elsevier.)


Visualization during diagnostic arthroscopy. ACL, Anterior cruciate ligament; PCL, posterior cruciate ligament.

(From Miller MD, Chhabra AB, Safran MR: Primer of arthroscopy, Philadelphia, 2010, Elsevier.)

Accessory portals for the knee include the posteromedial, posterolateral, far medial and lateral, and proximal superomedial portals. The posteromedial portal is often helpful for visualizing the posterior cruciate ligament and the posterior horn of the medial meniscus ( Fig. 94-5 ). The posterolateral portal, located just posterior to the lateral collateral ligament between the iliotibial band and the biceps tendon, sometimes is helpful, but extreme care should be taken to ensure that the portal is anterior to the biceps tendon to avoid injury to the peroneal nerve ( Fig. 94-6 ). An accessory medial portal has been developed for obtaining access to the appropriate angle for anatomic femoral tunnel placement in ACL surgery. Other portals include the midpatellar portal, far medial and lateral portals (which are sometimes helpful for instrument placement in hard-to-reach areas), and the proximal superomedial portal, located 4 cm proximal to and in line with the medial edge of the patella (for assessment of patellar tracking).

Feb 25, 2019 | Posted by in SPORT MEDICINE | Comments Off on Basics of Knee Arthroscopy
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