Osteotomy of the Femoral Lateral Collateral Ligament Insertion for a Tight Lateral Compartment in Complex Arthroscopic Knee Surgery

Abstract

Background:

In cases of complex arthroscopic knee surgery in the lateral compartment, such as performing lateral meniscus repair or transplantation, a tight lateral compartment can jeopardize the best possible care and could lead to iatrogenic cartilage injury. This technique shows a way to increase arthroscopic working space in a tight lateral compartment by performing an osteotomy of the femoral insertion of the lateral collateral ligament (LCL), utilizing a novel adjustable loop refixation technique.

Indication:

The femoral LCL insertion osteotomy can be performed if increased visualization and working space of the lateral compartment are needed during the complex arthroscopic knee surgery.

Technique Description:

After identification of the LCL femoral insertion, a 2-mm drill is passed through the LCL insertion to prepare for an anatomic reduction. The osteotomy is performed by taking a small bone plug together with the complete LCL insertion. Increased visualization and working space in the lateral compartment are obtained without damaging the intrinsic LCL structure. For reinsertion, the bone plug and proximal LCL is whipstitched with a high-strength suture and fixated to an adjustable loop Ultrabutton. The adjustable loop is shuttled through a predrilled 4.5-mm femoral tunnel and flipped on the medial side. The adjustable button is tensioned in 30° of flexion until the bone plug is anatomically reduced.

Results:

We present 1 patient who underwent a femoral LCL osteotomy during arthroscopic lateral meniscus allograft transplantation. The osteotomy healed without any issues, and there was no residual LCL laxity; which was confirmed with varus stress radiographs.

Discussion/Conclusion:

A femoral LCL insertion osteotomy can release a tight lateral compartment without damaging the intrinsic LCL structure. The adjustable loop fixation avoids the use of more traditional screw and washer fixation techniques, which tend to be more prominent and have the potential to back out. An osteotomy is more invasive than the “pie-crusting” technique of the medial collateral ligament for a tight medial compartment. However, it is required due to the poor intrinsic healing capacity of the LCL. Care should be taken to anatomically reduce the bone plug to avoid iatrogenic creation of LCL laxity.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

In this video, we will show a technique to create more working space in a tight lateral compartment during a complex arthroscopic knee surgery by performing an osteotomy of the femoral lateral collateral ligament insertion.

This video is by Wouter Beel, Emmanouil Papakostas, and Alan Getgood at The Fowler Kennedy Sport Medicine Clinic in London, Ontario, Canada, as well as the Aspetar Orthopedic and Sports Medicine Hospital in Doha, Qatar.

Our disclosures are listed here.

This is an overview of the presentation.

In arthroscopic knee surgeries, a tight tibiofemoral compartment can lead to iatrogenic cartilage injury and can jeopardize best possible care for the patient. In case of a tight medial compartment, percutaneous release of the medial collateral ligament (MCL), the so-called “pie-crusting” technique, is commonly used. ² A systematic review found no significant short- or long-term complications including no residual valgus instability, pain, loss of function, or damage to surrounding structures. An MCL release can, therefore, be justified during a simple arthroscopic surgery like partial medial meniscectomy. ²

The lateral collateral ligament (LCL) is the main static constraint to varus stress. An LCL release will increase the lateral working space by a mean of 2.71 mm. ³ In contrast to the MCL, which is a broad fan-like ligament, the LCL is a cord-like structure. Therefore, a “pie-crust”-like technique may jeopardize the ligaments’ integrity and raises concerns about iatrogenic residual lateral-sided laxity. The presented technique increases the lateral working space without damaging the intrinsic LCL integrity, by performing an osteotomy of the femoral insertion of the LCL at the lateral epicondyle.

The indications are limited to cases where a tight lateral compartment is encountered during a complex arthroscopic surgery. This mainly includes lateral meniscus allograft transplantation. Furthermore, it may be indicated during a repair of a complex traumatic lateral meniscal tear in a young patient, where a solid repair is crucial to save the meniscus and prevent early lateral compartment degeneration. However, we emphasize that this surgical technique is reserved for specific cases only due to the change in rehabilitation that is required postoperatively.

Our positioning of a patient undergoing a complex reconstructive knee surgery is supine with a lateral post at the proximal thigh and 1 foot-roll. A tourniquet is typically applied but only inflated when needed. A second foot-roll at the level of the distal femur can be used in case of combined anterior cruciate ligament reconstruction.

During the diagnostic arthroscopy, the lateral compartment is entered with the leg positioned in a figure of four. This video is made on a cadaver, and so no pathology is seen that warrants the osteotomy. If a tight lateral compartment is encountered, bringing the foot higher, such as resting it on a secondary horizontal post or mayo stand, while simultaneously pressing the knee down toward the bed might help to increase working space. Furthermore, changing the flexion angle might help as well. However, if these positional tricks are not sufficient and increased working space is needed, a decision can be made to perform an osteotomy of the femoral LCL insertion.

This is an intraoperative image of a case where we performed a combined lateral meniscus allograft transplantation with revision anterior cruciate ligament reconstruction and osteochondral allograft transplantation. Performing a meniscus transplantation would be impossible without causing iatrogenic cartilage injury during graft passage and suturing. In this case, we decided to perform an osteotomy of the femoral LCL insertion.

The location of the skin incision for the approach to the lateral epicondyle may alter depending on the combined procedure. Surgical landmarks are marked first. A maximum 4-cm skin incision is made centered over the femoral epicondyle. A subcutaneous preparation is done, and the iliotibial band is split longitudinally in line with its fibers centered over the epicondyle. The femoral LCL insertion is identified, and the osteotomy is marked with a blade. The osteotomy is performed with an 8-mm osteotome aiming to take a small bone plug, around 8 × 8 mm, together with the complete LCL insertion. A 2-mm drill is passed through the LCL insertion to prepare for an anatomic reduction in a later stage.

Now, the bone plug is completely freed up. Care should be taken not to damage the LCL. A #2 high-strength suture (Ultrabraid; Smith & Nephew Inc) is whipstitched through the bone block along the LCL and back through the bone block for later reinsertion. In this fashion, the LCL is released without damaging its intrinsic structure.

Now, an increased visualization and working space in the lateral compartment is obtained. This is an intraoperative image from the same case as previously mentioned, and a clear increase in working space can be appreciated. Enough space is obtained to perform the meniscus allograft transplantation. The surgery can now be proceeded with the other planned surgical steps.

At the end of the surgical procedure, the LCL is reinserted. First, the previously whipstitched Ultrabraid is tied over an adjustable loop Ultrabutton fixation device (Smith and Nephew Inc). The adjustable loop “cradle” facilitates the tying of the high-strength suture over the loop, still allowing for the sutures to slide and shorten the loop. A 2.4-mm eyelet pin is inserted into the defect of the LCL femoral insertion and overdrilled to the far medial cortex with a 4.5-mm drill.

Caution should be taken for possible tunnel coalition if performing concomitant anterior cruciate ligament (ACL) reconstruction. The adjustable button is shuttled through the femoral tunnel and flipped on the medial side. Correct deployment is controlled. The LCL is tensioned in 30° of flexion until the osteotomy is anatomically reduced by pulling the bone plug into its socket. Care should be taken not to over-tension the construct. The reduction is then controlled arthroscopically.

To avoid complications, it is important to ensure anatomic reduction as that might cause increased lateral-sided laxity or overtightening of the lateral side. The latter may, however, be wanted in a different setting, where retensioning of the lateral compartment is desired. Tunnel coalition in combined ACL/posterior cruciate ligament reconstruction is avoided while aiming 30° anteriorly and 30° proximally.^1,4 Furthermore, coalition can be assessed when drilling under arthroscopic view through the femoral tunnels. Correct deployment of the adjustable button on the medial cortex as well as applying a hinge brace helps to avoid secondary loss of LCL tension.

The postoperative rehabilitation and the return to sports will be dictated by the performed combined surgery. However, a hinged brace is applied for 6 weeks to ensure healing of the LCL osteotomy. Range of motion, as tolerated, and partial weightbearing are allowed.

We present 1 patient who underwent a femoral LCL osteotomy during lateral meniscus allograft transplantation. The osteotomy healed without any issues, and there was no residual LCL laxity, which was confirmed with varus stress radiographs taken at 6 weeks postoperatively.

To our knowledge, no previous reports are available on LCL insertion osteotomy to increase working space during an arthroscopic procedure. In the literature, an epicondylar osteotomy is mostly seen as combined osteotomy of the LCL and popliteus tendon insertion during open knee procedures. These include open lateral meniscus allograft transplantation and open-reduction internal fixation of tibial plateau fractures.^2,6 Verdonk et al ⁶ showed no complications due to epicondylar osteotomy in a series of 61 open lateral meniscus transplantation procedures.

Krause et al ² found no problems related to the epicondylar osteotomy performed during the treatment for tibia plateau fractures in their case series of 6 cases. These more extended osteotomies are reported to heal without any problem well as long as the bone block is at least 5 mm thick. ⁵

A femoral LCL insertion osteotomy is a surgical technique to increase visualization and working space in a tight lateral compartment. It helps to ensure the best possible surgical outcome, while reducing the risk of iatrogenic cartilage injury. However, it cannot be justified in simple arthroscopic procedures. Care should be taken to anatomically reduce the osteotomy to avoid iatrogenic created lateral-sided knee laxity.

The referred references are listed here.