Office-Based Needle Arthroscopy: A Standardized Diagnostic Approach to the Knee

Abstract

Surgical knee arthroscopy is among the most commonly performed procedures in the United States. The decision to treat is often based on clinical examination and magnetic resonance imaging. Equivocal results frequently require patients to undergo surgical arthroscopy, exposing the patient to inherent risks and potential surgical complications. Office-based needle arthroscopy provides an alternative approach to visualizing intra-articular anatomy and pathology in real time. The purpose of this article is to provide a standardized diagnostic approach to needle arthroscopy of the knee.

Figures

Fig 2

Standard portal sites (right knee). The medial (MED) and lateral (LAT) infrapatellar portal sites are identified approximately 1 cm above the tibial joint line and 1 cm medial or lateral to the border of the patellar tendon. The superolateral (SL) portal site is identified at the level of the superior aspect of the patella and 1 cm lateral to the lateral border of the patella. These sites are sterilized and anesthetized prior to needle arthroscope insertion.

Fig 3

Medial knee compartment visualized (right knee). Needle arthroscope inserted 1 finger's breadth above the joint line, just medial to the patellar tendon using a medial infrapatellar portal. A 30-mL syringe is connected to the outflow port on the arthroscope handpiece. The arthroscope is connected to the tablet placed on the ipsilateral side to allow for adequate visualization while performing the procedure.

Fig 4

Needle arthroscope configuration (right knee). The needle sheath is retracted once the surgeon is within the joint by pushing back on the gray retraction button found on superior portion of the arthroscope hand piece. This exposes the camera (not seen in this figure) within the sheath to allow for full visualization of intra-articular anatomy.

Fig 5

Medial meniscus (right knee). The needle arthroscope is introduced through the medial infrapatellar portal and pointed toward the notch. Once acceess has been obtained, the device is directed into the medial compartment. The surgeon can then systematically follow the medial meniscus to the midbody (MM) and then anterior horn. The medial femoral (MF) and tibial (MT) cartilage can be assessed through this portal as well.

Fig 6

Lateral meniscus (right knee). Using the medial infrapatellar portal, the lateral compartment is entered. The lateral meniscus (LM) is evaluated in a posterior-to-superior direction. Here a tear of the posterior horn of the lateral meniscus (star) is visualized. Inspection of the lateral femoral (LF) and tibial (LT) cartilage should be performed. If there is diffculty with visualization, the lateral infrapatellar portal may be used to complete the full assessment of the lateral compartment.

Fig 7

Anterior cruciate ligament (ACL) (right knee). The ACL and the intercondylar notch is visualized from the medial infrapatellar portal. The surgeon should thoroughly assess the ACL, inspecting both the tibial and femoral insertions. The knee may be brought in to a figure-4 position to tension the ligament and aid in visualizing the attachment to the medial aspect of the lateral femoral condyle (arrow). The lateral aspect of the medial femoral condyle (MFC) is labeled here for reference.

Fig 8

Positioning for access to patellofemoral joint (right knee). The patellofemoral joint can be accessed and inspected through the superolateral portal. The bump is removed from behind the knee prior to gaining access, allowing for full extension. The arthroscope should be advanced to the medial aspect of the patellofemoral joint. As the surgeon slowly withdraws the arthroscope, evaluation of cartilage integrity and patellofemoral tracking should be performed.

Fig 1

In-office room setup. A sterile field is created near the ipsilateral (right) knee to allow for adequate visualization of tablet and portal sites. A gel/foam bump is placed under the knee to provide for approximately 30°-45° of flexion. The distal extremity is wrapped with a sterile dressing to allow for manipulation.