The Transseptal Arthroscopic Knee Portal Is in Close Proximity to the Popliteal Artery: A Cadaveric Study

Abstract

The purpose of this study was to use fluoroscopy to measure the distance between the transseptal portal and the popliteal artery under arthroscopic conditions with an intact posterior knee capsule, and to determine the difference between 90 degrees of knee flexion and full extension. The popliteal artery of eight fresh-frozen cadaveric knees was dissected and cannulated proximal to the knee joint. The posterolateral, posteromedial, and transseptal portals were then established at 90 degrees of flexion. A 4-mm switching stick was placed through the transseptal portal, and barium contrast was injected into the popliteal artery. A lateral fluoroscopic image was taken with the knee in 90 degrees of flexion and full extension, and the distance between the popliteal artery and the switching stick was measured and compared using a paired -test. In knee flexion, the average distance between the transseptal portal and the anterior aspect of the popliteal artery for the eight cadaveric specimens was 12.0 mm ± 3.3 mm; in extension, this decreased to 9.0 mm ± 2.7 mm. The distance between the transseptal portal and popliteal artery was significantly higher at 90 degrees of knee flexion as compared with extension ( = 0.0005). The transseptal posterior knee arthroscopic portal must be carefully created due to the close proximity to the popliteal artery, and may be closer to the artery than previously reported in specimens with an intact posterior knee capsule. Creating the portal with the knee in flexion significantly displaces the popliteal artery away from the portal reducing the risk of arterial injury.

Surgical Management of the Multiple-Ligament Knee Injury

“…Measuring 2.5 cm distal to the medial epicondyle and then 2.5 cm posterior from that measured point, a spinal needle is inserted into the posteromedial compartment under direct arthroscopic visualization through the empty intercondylar notch. 24 A double-dam flexible wall flanged cannula is placed. Next a posterolateral portal is created, by spinal needle localization and arthroscopic illumination, well anterior to the long head of the biceps femoris and proximal to the LCL, of which the long head of the biceps and CPN have been previously identified through the open posterolateral approach.…”

Arthroscopic Synovectomy for Tenosynovial Giant Cell Tumor/Pigmented Villonodular Synovitis in the Posterior Knee Using the Posterior Trans-Septal Portal Technique

“…Keeping the knee in 90° of flexion provides the furthest distance from the saphenous vein on the medial side, the peroneal nerve on the lateral side, and the popliteal artery near the posterior septum when making the posterior portals 10-16 .Transillumination of the posterior portals is recommended 10-16 .Perforation of the septum should be in the posterolateral to posteromedial direction, allowing surgeons to have a wider “safe zone” to decrease the chance of vascular injury to the popliteal artery 14 .…”

“…The trans-septal portal (TSP) technique utilizes both posteromedial and posterolateral portals to create an intra-articular portal through the posterior septum that separates the 2 posterior compartments of the knee 10-15 . This portal allows working instruments to be passed back-and-forth across the posterior septum and increases the visualization of both the posterosuperior synovial lining of the condyles and the synovial reflection behind the posterior cruciate ligament, enabling a thorough assessment for arthroscopic PVNS resection 10-16 . In this video article, we describe a posterior arthroscopic synovectomy with use of a TSP for PVNS within the posterior compartment of the knee.…”

“…In 2019, the FDA approved the use of CSF-1 inhibitors, and they are considered an acceptable treatment for patients who are not candidates for surgical resection 17 . Rationale: Advantages involve increased posterior anatomy visualization to ensure adequate synovectomy, more working capacity for instruments, and decreased disruption of anatomical planes and scar tissue formation around neurovascular structures compared with open dissection [10][11][12][13][14][15][16] . Expected Outcomes: Excellent clinical results (defined by return to full knee function) have been reported for the TSP technique for PVNS synovectomy.…”

Commentary: “An Imaging Overview of the Posterior Septum of the Knee and Trans-Septal Portal Procedure: Normal Anatomy, Indications, and Unique Imaging Considerations”

“…When creating the posteromedial, posterolateral portal, and trans-septal portal, the knee should be flexed 90 degrees to provide the furthest distance from the saphenous vein (16-28 mm) on the medial side, the peroneal nerve (32-40 mm) on the lateral side, and the popliteal artery near the posterior capsule and septum [13][14][15][16][17] . Approximately, 90° of knee flexion provides the greatest distance from the respective anatomical structure(s) and should be maintained throughout the procedure.…”