Overview
Arthroscopy is most widely applied at the knee, where it is both a diagnostic and a therapeutic tool. Campbell stresses that it is an adjunct to, not a replacement for, a thorough history, physical examination and appropriate imaging. With MRI and better clinical tests, arthroscopy is now rarely done for diagnosis alone. (Campbell)
Indications
Diagnostic arthroscopy is the essential first step before operative arthroscopy or before an open arthrotomy.
Operative arthroscopy: meniscal surgery, loose body removal, plica excision, treatment of osteochondral lesions, cruciate ligament reconstruction and arthrofibrosis release. (Campbell, Chapter 56 contents)
Technique: Basic Diagnostic Arthroscopy of the Knee (Campbell Chapter 56)
Operating room setup
Perform the procedure in the operating room under strict sterile conditions. Infection is infrequent (<1%), but is as devastating as after arthrotomy.
Use waterproof arthroscopy gowns and drapes. Seal the limb proximal and distal to the surgical site, and use a durable skin preparation and an iodine-impregnated drape.
Place the instrument table on the side of the operative knee and a Mayo stand over the upper thighs for frequently used instruments.
Hang irrigation bags 3–4 feet above the patient. An arthroscopic pump gives constant flow and pressure and may remove the need for a tourniquet.
To stress the knee, use a padded lateral post or a commercial leg holder. The post helps valgus stress near extension but does not control rotation. Commercial thigh holders are most effective but carry potential hazards.
Anesthesia
General, regional or local anesthesia can be used.
For short, uncomplicated procedures in cooperative patients, regional or local anesthesia is possible. Campbell prefers intravenous sedation with 1% lidocaine for the portals and an intraarticular bolus of 30 mL bupivacaine plus 15 mL lidocaine 20 minutes before starting.
Diagnostic arthroscopy before arthrotomy or major intraarticular surgery is best done under general anesthesia unless contraindicated.
Tourniquet
Place a thigh tourniquet but leave it uninflated in diagnostic arthroscopy unless bleeding becomes troublesome. Inflation blanches the synovium and makes assessment harder.
Evaluate meniscal vascularity and healing potential with the tourniquet deflated and low intraarticular pressure.
Inflate after exsanguination for acute traumatic disorders or for anything beyond the simplest procedures.
Keep tourniquet time under 90 minutes for routine procedures to limit DVT. For major complicated procedures up to 2 hours can be used. Avoid longer to prevent ischemic neurovascular changes.
Positioning
Prepare the limb from ankle to tourniquet as for an open arthrotomy, and isolate the foot, lower leg and distal thigh with an arthroscopy drape.
Supine with the limb angled off the lateral side of the table, using a leg holder or lateral post:
The surgeon stands on the inside of the abducted leg, with the patient's foot on the surgeon's hip or iliac crest area. Leaning against the leg gives valgus stress and opens the medial compartment.
To examine the lateral compartment, the assistant holds the leg in a figure-four position.
Alternatively, position the knee just past the distal break point of the table and drop the end so both limbs hang at 90 degrees. Pad the opposite limb. Flexing the middle of the table with a padded bolster flexes the hips, relieves stretch on the femoral nerve and flattens the lumbar spine.
Wrap the uninvolved limb with an elastic wrap or stocking to reduce venostasis. A well-leg support is another option.
Portal placement
Success depends on adequate light, joint distention and precise portal location.
Before distention, mark with a pen: the patella and patellar tendon outlines, the medial and lateral joint lines (palpated), and the posterior contours of the femoral condyles. Recheck after distention.
A small outflow needle cannula can be placed superomedially or superolaterally, with inflow through the arthroscope. This is usually needed for large procedures such as ACL reconstruction when hemarthrosis is present.
Avoid passing through the vastus medialis obliquus, which may speed rehabilitation.
Standard portals
Anterolateral. The single most useful portal. Use a 4-mm, 30-degree scope. It sits about 1 cm above the lateral joint line, 1 cm lateral to the patellar tendon and 1 cm below the patella. Palpate the inferior pole of the patella so the portal is not placed too high.
Too low or too close to the joint line risks damage to the anterior horn of the lateral meniscus, or passage of the scope through or beneath it.
Too high prevents viewing of the posterior horns and posterior structures.
Directly beside the tendon, the scope may penetrate the fat pad and be hard to maneuver.
Anteromedial. Used for additional viewing of the lateral compartment and for the probe. Placed like the anterolateral portal, 1 cm above the medial joint line, 1 cm below the patella and 1 cm medial to the tendon. Confirm placement with a spinal needle seen from the anterolateral portal. Visualize the No. 11 blade with the cutting edge facing away from the meniscus.
Posteromedial. Used for repair or removal of displaced posterior horn tears and posterior loose bodies, and always for PCL reconstruction. Some surgeons use it routinely when the ACL is torn, to exclude a medial meniscal ramp lesion. It sits in the soft spot between the posteromedial femoral condyle and tibia, about 1 cm above the joint line and 1 cm behind the condyle. Three rules:
Distend the knee maximally so the posteromedial compartment balloons out.
Flex the knee close to 90 degrees.
Draw the landmarks before distention.
Superolateral. Lateral to the quadriceps tendon and about 2.5 cm above the superolateral patellar corner. Best for viewing patellofemoral tracking and, with a 70-degree scope, the patellar tendon.
Optional portals
Posterolateral. Helps with lateral meniscal repair. Knee at 90 degrees, joint maximally distended. Located where a line along the posterior femoral shaft meets one along the posterior fibula, about 2 cm above the joint line between the posterior iliotibial band and biceps femoris tendon. Make a 6-mm incision and enter with the sheath and trocar, sliding off the posterior condyle parallel to it. Avoid plunging through the capsule into the popliteal space. Outflow of irrigant confirms entry.
Proximal midpatellar medial and lateral. At the broadest part of the patella. They improve viewing of the anterior compartment, lateral meniscocapsular structures and popliteus tunnel and reduce instrument crowding. They are Campbell's preferred accessory portals for anterior compartment procedures. Do not confuse them with the transpatellar tendon portal.
Accessory far medial and lateral. About 2.5 cm medial or lateral to the standard portals, used to triangulate instruments. Locate them with a spinal needle seen arthroscopically, entering above the superior meniscal surface. The margin for error is small: the meniscus, collateral ligament or condylar cartilage can be injured.
Central transpatellar tendon (Gillquist). About 1 cm below the lower pole of the patella, through the tendon, with the knee at 90 degrees. Not routinely advocated because of tendon damage. If used in ACL reconstruction, make it after graft harvest.
Insertion of the scope
When the tourniquet is not inflated, infiltrate portal sites with 4 to 5 mL of local anesthetic with epinephrine. More than this can distend the fat pads and obscure the view. If the tourniquet will be inflated, portals are usually not infiltrated.
Systematic examination
Follow the same sequence in every knee. Campbell divides the knee into seven compartments:
Suprapatellar pouch and patellofemoral joint
Medial gutter
Medial compartment
Intercondylar notch
Posteromedial compartment
Lateral compartment
Lateral gutter and posterolateral compartment
The posteromedial compartment is seen by passing the scope through the intercondylar notch or through a separate posteromedial portal. The posterolateral compartment can usually be seen from an anterior portal. If not, use a direct posterolateral portal.
Postoperative Care
Rehabilitation depends on the procedure performed (meniscectomy, repair, ligament reconstruction). See the specific technique guides.
Complications
Overall rate. Four large series (191,584 procedures) reported complications in 0.6%, most commonly infection and DVT or pulmonary embolism. American Board of Orthopaedic Surgery data (2003–2009) showed an overall rate of almost 5%, from 2.5% for meniscectomy to 20% for PCL reconstruction, with infection the most common. (Campbell)
Nerve injuries. Saphenous and peroneal nerve injuries are still reported with arthroscopic meniscal repair, but have fallen dramatically with all-inside techniques. (Campbell)
DVT. A concern with long, complicated procedures, especially in overweight patients, those with prior DVT, those taking birth control pills or those immobilized by injury. In high-energy knee injuries with treatment delayed more than 2 weeks, preoperative lower-extremity ultrasound is usually done. If weight bearing is limited, aspirin 81 mg twice daily is probably warranted, and sequential compression may be used in high-risk patients. (Campbell)
Infection. Slightly more frequent when ACL reconstruction is combined with meniscal repair. Treat with early, thorough arthroscopic irrigation and debridement, repeated at 48–72 hours if symptoms persist. ACL grafts can be left in place if there is no extensive deterioration. Give IV antibiotics for 2–3 weeks, then oral antibiotics to complete 6 weeks. About 85% of grafts are salvaged. (Campbell)
Contaminated graft. Retrieve it immediately, rinse with a large volume of sterile saline, soak in 4% chlorhexidine gluconate (at least 90 seconds, Campbell recommends 10 minutes) and then in neomycin–polymyxin B (same durations), and rinse again. (Campbell)
Other. Arthrofibrosis, complex regional pain syndrome and failure of graft incorporation. Early ligament surgery before motion and muscle tone return is associated with arthrofibrosis, as is combined meniscal repair. Letting the knee calm and regain motion before surgery greatly reduces postoperative stiffness. (Campbell)
References
Bernholt DL, Mihalko MJ. Arthroscopy of the lower extremity. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 56, Knee: basic diagnostic techniques.