Arthroscopic Release of the Deep Medial Collateral Ligament to Assist in Exposure of the Medial Tibiofemoral Compartment

Abstract

Arthroscopy of the knee is a widely used surgical procedure for addressing intra-articular pathology. In assessing the intra-articular structures, visualization is of paramount importance. The medial tibiofemoral compartment is often difficult to fully visualize in tight knees in which limited access can compromise surgical efficacy. Poor visualization can increase the possibility of a residual meniscal tear after attempted partial meniscectomy, as well as the possibility of iatrogenic chondral injury from arthroscopic instruments. We describe a technique that allows improved medial tibiofemoral visualization with release of the deep medial collateral ligament. We use standard arthroscopic portals, without the need for further incisions or stab holes and with minimal additional patient morbidity. This procedure allows easier exposure of the medial knee chondral surfaces and meniscus and easier use of arthroscopic instrumentation in the medial compartment.

Arthroscopic knee procedures are performed for a variety of knee pathologic conditions with good results and an increasing incidence. Approximately 1 million arthroscopic knee procedures, of which 700,000 were meniscal resections, were performed in the United States alone in 2006, with an increasing incidence seen internationally as well.^1,2 To achieve good outcomes, adequate visualization of the intra-articular structures is crucial. Commonly, tightness is encountered in the medial compartment and hinders sufficient visualization and use of arthroscopic instrumentation.^3,4 Arthroscopic visualization of the posterior horn of the medial meniscus is especially difficult, with inadequate visualization in tight knees leading to the possibility of complications. These include missed or incomplete treatment of meniscal and chondral pathology and iatrogenic injury to the meniscus and cartilage, as well as prolonged operative time.^3-5 Different methods have been described to aid in visualization, including posteromedial portal placement⁶ and needle-assisted medial collateral ligament (MCL) release.^5,7

The purpose of this article is to describe an alternative arthroscopic surgical technique that can easily be used to allow greater access to the medial compartment. We describe a technique that involves no need for new or further incisions or percutaneous stab wounds. Our technique maximizes access to the medical compartment with minimal increase in associated iatrogenic complications and patient morbidity through the use of already established standard portals.

Surgical Technique

Patient Positioning

We proceed with our standard setup for knee arthroscopy, which involves placing the patient supine with a nonsterile tourniquet placed on the upper thigh. A 10-lb sandbag is taped to the distal aspect of the table for the foot to rest, allowing the knee to flex at 90° for work in the intra-articular notch. A bump (i.e., a folded blanket) is placed under the patient's ipsilateral hip. A well-padded post is placed at the level of the patient's distal femur with the leg extended. The post allows for application of valgus stress and medial joint opening. The leg is then prepared and draped in the usual sterile manner.

Portal Placement

With the knee flexed, by use of a No. 15 blade, a stab incision is made along the anterolateral aspect of the knee, just lateral to the patellar tendon, to create the anterolateral portal. A 30° arthroscope is introduced into the suprapatellar pouch as the leg is extended and the correct placement in the joint is confirmed. Our standard diagnostic knee arthroscopic evaluation begins in the suprapatellar pouch, followed by the lateral gutter and then the medial gutter. The knee is bent 90°, and the anterior aspect of the medial tibiofemoral joint is visualized. An anteromedial portal is made under direct visualization using a spinal needle whose entrance is about 10 mm medial to the patellar tendon. After visualization of the anterior horn of the medial meniscus and the distal and posterior chondral surfaces of the medial femoral condyle, the knee is extended and an assistant places valgus stress on the knee. The mid and posterior aspect of the medial joint is visualized, and the surgeon performs an assessment of medial opening with the knee under valgus stress. When a “tight” knee is encountered, defined as a knee that does not allow sufficient visualization and instrumentation of the posterior medial tibiofemoral structures (Fig 1A), the decision is made to proceed with a release of the deep MCL at its meniscocapsular attachment. An example of this technique is shown in Video 1.

Fig 1.

Steps of arthroscopic deep MCL release in 1 patient. The medial compartment is visualized by a 30° arthroscope through standard (A) anterolateral and (B) anteromedial portals. With valgus stress placed on the knee near full extension, a 4-mm probe points to the medial femoral condyle. This shows the tight nature of the compartment and inadequate visualization of the posterior structures. (C) A sled is introduced into the medial compartment from the lateral portal, which will protect the tibial chondral surface during blade advancement. (D) A 3.0-mm banana blade is introduced over the meniscal repair sled underneath the medial meniscus to release the deep MCL. (E) The deep MCL is released, starting from the middle third of the medial meniscus, working posteriorly. (F) The release is continued posteriorly only as much as is needed to sufficiently visualize all posterior medial structures. After the release has been performed, the same 4-mm probe is seen from the (G) anteromedial and (H) anterolateral portals, showing improved visualization and identification of a bucket-handle medial meniscal tear that was previously obscured.

Deep MCL Release

The deep MCL is released using the lateral working portal under direct visualization from the anteromedial portal. The arthroscope is first changed to the anteromedial portal over a switching stick, and the surgeon again inspects the medial tibiofemoral joint, confirming inadequate visualization of the medial compartment (Fig 1B). A meniscal repair sled may be introduced from the anterolateral portal to avoid injury to the tibial cartilage (Fig 1C). Then, a 3.0-mm Acufex straight serrated disposable banana blade (Smith & Nephew, Memphis, TN) is inserted for the release (Fig 1D). A gentle curve is added to the banana blade's shaft to facilitate passage over the tibial spines and safe access to the undersurface of the medial meniscus (Fig 2). The middle third of the medial meniscus is visualized, and the banana blade is slid under the meniscus with care taken not to cause iatrogenic injury to the meniscus or chondral surface of the tibia. With valgus stress still being applied, the blade is then used to release the deep MCL and meniscocapsular attachments, working generally from the middle third of the meniscus posteriorly.

Fig 2.

Banana blade. A slight curve is introduced into the blade to facilitate safe access to the undersurface of the medial meniscus.

During the release, it is important to keep a constant valgus stress on the knee to hold the deep MCL and its meniscocapsular attachments taut. The banana blade is then pushed into the ligament until medial widening is achieved, often accompanied by an audible sound indicating ligament release. Generally, a pushing motion into the ligament is preferred over a sliding motion because the latter precludes the surgeon from noticing how deep into the meniscocapsular structures the banana blade has advanced. The release is continued posteriorly only as much as is required to adequately visualize the posterior structures (Fig 1 E and F). Immediate opening of the compartment is noted, and sufficient visualization is used as the guide to determining whether the release is adequate (Fig 1G).

Once the release is complete, minimal valgus stress is needed for excellent medial knee visual exposure. The arthroscope is placed into the anterolateral portal once again, and the appropriate meniscus evaluation and treatment are then carried out with standard arthroscopic technique (Fig 1H). After treatment of the medial knee pathology is complete, the knee is again placed in 90° of flexion for evaluation and treatment of the contents of the intercondylar notch; lastly, the lateral tibiofemoral compartment is visualized with standard figure-of-4 valgus stress. Table 1 summarizes the indications, contraindication, advantages, and pearls to avoid complications of this technique.

Table 1.

Indications, Contradiction, Advantages, and Pearls to Avoid Complications

Indications

Tight medial tibiofemoral compartment with inadequate visualization of posterior structures

Tear of posterior horn of medial meniscus

Contraindications

Acute MCL injury

Advantages

No need for new incisions or arthroscopic portals

Maximization of safe access to medial compartment

Easier use of instrumentation in addressing meniscal and chondral pathology

Avoidance of iatrogenic injury to cartilage

Decreased chance of missing intra-articular pathology because of poor visualization

Pearls to avoid complications

Having a gentle curve on the banana blade shaft allows advancement over the tibial spines and sliding under the medial meniscus.

Using a sled protects the tibial chondral surface during blade advancement.

Constant valgus stress holds the deep MCL and its meniscocapsular attachments taut and guides the minimal amount of release necessary for sufficient visualization.

The “push method” while releasing the deep MCL allows visualization of the blade tip and a controlled release without advancing the blade too deep.

Postoperative Course

Postoperatively, the patient is treated with procedure-specific immobilization and physical therapy, with weight bearing as appropriate. The addition of the deep MCL release does not alter the postoperative plan and does not require additional bracing. Of note, increased medial knee swelling is often seen that resolves over the course of a few days.

Discussion

Access to the medial knee is paramount in allowing adequate visualization and treatment in arthroscopic surgery. Difficulty in obtaining adequate access to the medial compartment has been cited in the literature,^3,4 and techniques to allow opening of the space have been described.^5,7 We discuss a technique that allows release of the deep MCL to better visualize the medial tibiofemoral compartment through standard arthroscopic portals, without the need for further incisions or stab wounds and with minimal patient morbidity. Using this step during an arthroscopic procedure in a patient with a tight medial knee allows easier use of the instrumentation in addressing meniscal and chondral pathology and avoidance of unnecessary iatrogenic complications such as articular cartilage damage or the risk of missed pathology.

We have performed a deep MCL release in more than 35 patients (aged 13 to 60 years) since 2010. Our treatment has not resulted in any need for a postoperative period of bracing or immobilization or any instances of chronic MCL valgus laxity. Only 1 patient, a 22-year-old female Division 1 volleyball player, has undergone a repeat arthroscopy. In this patient, 13 months after the initial medial meniscus repair, there was clear evidence of MCL healing and another release was required to again allow access to the medial compartment.

Supplementary Data.

Video 1

Our technique enables visualization of the medial tibiofemoral compartment and deep MCL release, with ample room for meniscectomy. A view of the medial compartment is shown with poor visualization of a medial meniscal tear and poor access to the tear in the posterior horn. The arthroscope is shown in the lateral portal, and a banana blade is inserted from the medial portal to perform the deep MCL release. The meniscectomy is shown in the released medial compartment, with ample room and access to perform the procedure.