Abstract
Background:
The arthroscopic approach to the posterior compartment of the knee is always challenging. This easy arthroscopic transseptal approach allows safe access to the posterior compartment of the knee, avoiding any potential neurovascular injury.
Indications:
Indications include arthroscopic posterior cruciate ligament (PCL) reconstruction, fixation of avulsion fractures of the tibial attachment of the PCL, arthroscopic posterolateral corner reconstruction, removal of loose bodies from the posterior compartment, PCL cyst removal, ramp repair, and arthroscopic arthrolysis of the posterior compartment.
Technique Description:
Using a posteromedial portal, a shaver is introduced with the tip in direct contact with the medial side of the septum facing anteriorly, away from the popliteal neurovascular bundle. The scope is then inserted into the posterolateral compartment to visualize the lateral side of the septum while the shaver remains in the posteromedial compartment. The septum is then released until the tip of the shaver is visible. The shaver is then removed and the scope can now be inserted from the posteromedial portal to the posterolateral compartment through the released septum.
Results:
The transseptal approach can be performed without any additional risk if the shaver remains centrally on the inferior aspect of the septum. Therefore, the risk of iatrogenic injury of the middle genicular artery is minimized. Likewise, with the knee flexed to 90°, there is no risk of damaging the popliteal neurovascular bundle. Having a precise knowledge of the anatomy of the posterior compartment of the knee minimizes any risks of the transseptal approach, avoiding any additional surgical time whilst facilitating the indicated operation.
Conclusion:
This easy arthroscopic transseptal approach allows safe access to the posterior compartment of the knee, avoiding any potential neurovascular injury.
This is a visual representation of the abstract.
Keywords
Video Transcript
Arthroscopic visualization of the posterior compartment of the knee can be very challenging. However, a transseptal approach can facilitate or even simplify numerous procedures whilst avoiding any potential neurovascular injury. The aim of this video is to present a simplified, safe and reproducible visualization of the posterior compartment of the knee through an easy arthroscopic transseptal approach.
Indications include posterior cruciate ligament (PCL) reconstruction, fixation of avulsion fractures of the tibial attachment of the PCL, posterolateral corner reconstruction, removal of loose bodies from the posterior compartment, PCL cyst removal, ramp repair, and arthroscopic arthrolysis of the posterior compartment.
There are a number of key steps to facilitate this easy transseptal approach.
First, the patient should be positioned supine with the knee flexed to 90° which provides the greatest distance from the surrounding neurovascular structures. A tourniquet is also applied high on the thigh. Transillumination can aid in the placement of the posteromedial portal by inserting a needle in the safe zone. This avoids vascular injury and ensures the portal is not too close to the femoral condyle in order to manipulate the instruments. Once the posteromedial portal has been performed, a shaver can be introduced to gently remove the central inferior septum to avoid iatrogenic injury to the middle genicular vessels. The blade of the shaver should always face anteriorly toward the joint and therefore away from the popliteal neurovascular bundle as demonstrated in the anatomical illustration.
If a posterolateral portal is required, transillumination and guidance with a spinal needle should be used to avoid neurovascular injury and ensure correct positioning of the portal. The portal should be posterior to the lateral collateral ligament and popliteus tendon at the level of the joint line to allow adequate access to the popliteus tendon and fibular head.
First, we demonstrate the easy arthroscopic transseptal approach in a cadaver. The scope is pushed deep in the notch between the triangle formed by the medial femoral condyle, the tibial spine, and the PCL to enter the posteromedial compartment. When the knee is flexed to 90°, the posteromedial bundle of the PCL is relaxed and makes this easier. A posteromedial portal is made, ensuring it is not too close to the femoral condyle in order to manipulate the shaver, the scope or a suture hook if a ramp lesion is present. Transillumination helps to place the needle in the safe zone to avoid vascular injury.
Once the posteromedial portal is performed, a shaver can be introduced through the posteromedial portal to gently remove the central inferior septum to avoid iatrogenic injury to the middle genicular vessels. The blade of the shaver faces toward the scope to ensure it is away from the popliteal neurovascular bundle.
The shaver is then pushed against the septum and the surgical assistant holds the shaver in this position and the scope is removed. The scope is then placed from the anteromedial portal to the posterolateral compartment by pushing the scope deep in the notch between the triangle formed by the lateral femoral condyle, the tibial spine, and the anterior cruciate ligament.
By turning the scope medially, the lateral side of the septum can be visualized. The shaver is then pushed from the other side of the septum until the tip can be felt. The septum can now be carefully released from medial to lateral until the tip of the shaver is fully visualized. The transseptal approach has now been successfully performed.
The arthroscope can now be placed from the posteromedial portal, through the open septum to the posterolateral compartment. A posterolateral portal can be performed with the guidance of transillumination to avoid neurovascular injury. After palpation of the softspot between the posterior border of the iliotibial band and the anterior border of the biceps femoris, a spinal needle can be inserted in order to ensure the correct position of the portal. Subsequently, an incision can be made with a scalpel blade in line with the needle to visualize the entry into the posterolateral compartment. The posterolateral portal placement should be posterior to the lateral collateral ligament and popliteus tendon at the level of the joint line to allow adequate access to the popliteus tendon and fibular head. Radiofrequency ablation can be used for further release of the posterior aspect of the septum using the posterolateral portal.
We now present the easy transseptal approach in a real patient. The triangle formed by the medial femoral condyle, the tibial spine, and the PCL is clearly identified which allows access to the posteromedial compartment. Careful positioning of the posteromedial portal using a needle ensures it is not too close to the femoral condyle in order to manipulate the instruments.
Again, the blade of the shaver faces toward the scope to ensure it is away from the popliteal neurovascular bundle. The septum is then carefully released from medial to lateral until the tip of the shaver is fully visualized. The arthroscope is then inserted from the posteromedial portal, through the open septum to the posterolateral compartment. The posterolateral portal can be performed under direct vision and radiofrequency ablation can be used to fully release the posterior aspect of the septum allowing a clearer vision of the entire posterior compartment.
This 16-year-old female patient sustained a multiligament knee injury whilst trampolining with involvement of the anterior cruciate ligament, PCL and medial collateral ligament. In addition, she had tears of her medial and lateral menisci. An open approach was used to repair the medial collateral ligament and an arthroscopic transseptal approach was used for the PCL reconstruction.
Transnotch visioning allows satisfactory positioning of the posteromedial portal to ensure it is not too close to the femoral condyle. This was facilitated by transillumination and the approach for the medial collateral ligament repair which was already performed. The posteromedial portal was initially used to repair the ramp lesion which is clearly identified due to the recent injury. Initial debridement is performed with the shaver to further identify the tear and facilitate the repair.
The shaver is then pushed toward the central inferior septum to avoid iatrogenic injury to the middle genicular vessels. The blade of the shaver always faces anteriorly toward the scope to avoid injury to the neurovascular bundle. With the surgical assistant holding the shaver, the scope is then switched from the anterolateral portal to the anteromedial portal, and the tip of the shaver is identified.
The septum is now carefully released from medial to lateral until the tip of the shaver is fully visualized. Multiligament injuries of the knee often have a significant amount of this dissection already completed due to the initial trauma. As this approach does not involve significant capsular incisions, the risk of fluid extravasation and compartment syndrome is not greater than standard approaches.
The scope can now be switched from the anteromedial portal to the posteromedial portal and transseptal vision of the posterolateral compartment can now be achieved.
A posterolateral portal is then placed using transillumination and guidance with a needle to avoid neurovascular injury and ensure correct positioning of the portal. The portal should be posterior to the lateral collateral ligament and popliteus tendon at the level of the joint line to allow adequate access. Radiofrequency ablation is then used to release any remaining segments of the posterior septum and to debride the PCL tibial stump.
Once the PCL tibial insertion site is clearly identified, a tibial guide is positioned and a guidewire is inserted. The easy transseptal approach provides clear visualization of the entire posterior compartment which ensures safe positioning of the wire. Likewise, drilling of the PCL tibial tunnel can be performed safely and effectively. A curette can be positioned via the posterolateral portal as an additional precaution to avoid neurovascular injury.
Tips and tricks of the easy arthroscopic transseptal approach are outlined in Table 1. When positioning the posteromedial portal, ensure not to be too close to the femoral condyle and use transillumination to avoid neurovascular injury. The shaver should always face anteriorly to avoid damage to the popliteal neurovascular bundle. Using transillumination and a needle to place the posterolateral portal ensures correct positioning.
In conclusion, this easy arthroscopic transseptal approach allows safe access to the posterior compartment of the knee, avoiding any potential neurovascular injury.
Tips and Tricks
Footnotes
Submitted November 22, 2021; accepted February 7, 2022.
One or more of the authors has declared the following potential conflict of interest or source of funding: B.S.-C. received support from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
