Open Reconstruction of Fibular Collateral Ligament Rupture Using a Partial-Thickness Biceps Femoris Tendon Autograft

Abstract

Background:

Fibular collateral ligament (FCL) injuries are uncommon incidents, with less favorable healing rates compared to medial collateral ligament injuries, often necessitating repair or reconstruction as the predominant treatment approach.

Indications:

Using a partial-thickness biceps femoris tendon (PTBFT) autograft for FCL reconstruction or augmentation is a viable option for both acute and chronic FCL injuries, especially in patients unwilling to accept allograft tissue and in settings with limited access to allografts.

Technique:

The fibular head attachments of the biceps femoris tendon (BFT), FCL, and popliteofibular ligament are inspected for injury. The biceps–iliotibial band (ITB) interval is opened, and the native FCL is assessed at its midsubstance for injury. The mid-aspect of the ITB was incised in line with its fibers, and the femoral insertion of FCL is localized. A 10-mm × 70-mm graft is harvested from the middle third of the BFT, preserving the distal insertion on the fibular head. Locking Krackow sutures are placed into the proximal end of the graft, which is passed under the ITB. A femoral tunnel is created at the FCL attachment site, and the graft is placed into the femoral tunnel and secured to the femur using an interference screw.

Results:

Postoperatively, the patient is instructed on foot-flat touch weightbearing with 2 crutches, on a knee immobilizer, for the first 2 weeks. Increasing weightbearing status and range of motion are expected in a stepwise manner. Return to sports is permitted after 6 to 9 months and depends on the presence of any additional injuries, strength, and functional recovery. There no studies available yet on clinical outcomes.

Discussion/Conclusion:

FCL reconstruction or augmentation utilizing a PTBFT autograft is an underused treatment option for patients with isolated FCL insufficiency or as part of multiligamentous injuries. This procedure offers advantages such as an anatomic reconstruction; single incision for both graft harvest and FCL reconstruction; shorter, cost-effective surgery with fewer implants used; and a safer approach with reduced risk of neurovascular structures due to lack of a fibular head tunnel. This is a valuable option in the limited source setting or in a patient not accepting of allografts.

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

This video demonstrates our approach to fibular collateral ligament (FCL) reconstruction or augmentation utilizing a partial-thickness biceps femoris tendon (PTBFT) autograft in a patient with FCL insufficiency.

Here are the disclosures from our authors.

Here is an outline of the presentation topics we will discuss today.

Background

The FCL, also known as the lateral collateral ligament (LCL), originates 1.4 mm proximal and 3 mm posterior to the lateral femoral epicondyle and inserts distally 8.2 mm posterior to the anterior margin of fibular head. ⁵

It is a crucial component of the posterolateral corner structures and plays a vital role in knee stability against varus forces at all flexion angles.^8,10

The short head and long head of the biceps femoris (BF) merge distally and attach to the entire lateral aspect of the fibular head and lateral cortex of the proximal tibia. The primary function of the BF is to flex the knee and externally rotate the tibia during knee flexion. ¹

FCL injuries are uncommon, often occurring as part of a posterolateral corner injury and commonly accompanied by unicruciate or bicruciate ruptures.

The most common mechanisms of injuries for the FCL include a direct blow to the medial knee, twisting of the knee, and hyperextension.^8,10

Treatment of FCL injuries depends on the degree of the injury and the timing from injury to presentation to the surgeon.

Third-degree injuries are often managed operatively. In the acute setting, repair has been shown to have a favorable outcome for ruptures at the distal or proximal insertion. Mid-substance ruptures, as well as subacute and chronic injuries, are typically managed with FCL reconstruction.^5,8,9

Third-degree FCL injuries will show increased lateral joint line widening greater than 2.7 mm compared to the contralateral side during the varus stress test at 30°.^3,8

The initial description of using the biceps tendon for FCL reconstruction was presented by Clancy, ² who advocated for the transfer of the entire biceps tendon to reconstruct the FCL. This procedure fell out of favor since it eliminated the natural function of the biceps tendon in knee flexion and tibia external rotation, and it diminished its role as a dynamic stabilizer of the knee.

Various modifications of this technique have been introduced, taking into account preservation of BF function while maintaining an anatomic origin and insertion site.^3,4,8,9

Various options have been described for FCL augmentation and reconstruction. This includes using different autograft options, along with various allograft options. ⁶

The utilization of a partial-thickness biceps tendon autograft for FCL augmentation offers several advantages. These include an anatomic reconstruction and the use of a single incision for both graft harvest and FCL augmentation or reconstruction, resulting in a shorter operative time. Additionally, this technique requires less dissection around the fibular head, potentially reducing the risk of neurovascular injuries. ⁷ These considerations are particularly crucial, especially in settings with limited resources or when patients are not open to accepting allografts.

FCL reconstruction using hamstring autograft or allograft is often employed. ⁶ While hamstring autograft offers the advantage of better potential healing, the drawback is the potential need for 2 separate incisions and fixation points in both the fibular and femoral tunnels, along with increased dissection around the fibular head for tunnel placement and graft passage.

While allograft offers the advantage of avoiding donor site morbidity, it comes with the disadvantage of potentially biologically inferior healing, increased risk of infection, and an increase in the overall cost of surgery. ⁶

Indications

Our case begins with a 20-year-old female soccer player who sustained a knee injury when an opposing player hit the anteromedial side of the knee while tackling. The patient had immediate pain, had difficulty weightbearing, and was unable to return to play.

On office examination, the patient's right knee range of motion was 3 cm of heel-to-table distance and flexion to 135° (normal side: 4 cm of heel-to-table distance and flexion to 140°). She had a grade 2B Lachman test and a grade 2 pivot-shift test. Varus stress test at 0° was symmetric, but at 30°, it showed approximately 6 mm of increased lateral joint space widening compared to the contralateral side. The rest of the examination yielded normal results.

Radiographic imaging was normal. The results from coronal and sagittal T2-sequence magnetic resonance imaging indicated a complete mid-substance anterior cruciate ligament (ACL) and FCL tear. BF and popliteus tendons were intact.

The patient's history, physical examination, and imaging collectively revealed a complete tear of both the ACL and the FCL in an individual with an unstable knee, desiring a return to an aggressive pivoting sport activity. The patient was counseled about various treatment options, including nonoperative versus surgical reconstruction of the ACL and FCL, and the patient chose the surgical option.

Technique Description

The next few slides are a review of the BF graft harvest that will also be demonstrated in the surgical video to follow. An ~8-mm-wide graft centered at the junction of the anterior-middle one-third of the BF is harvested, leaving the fibular attachments intact. A 7- to 8-cm-long graft is created with length determined by the length of the patient's native LCL. A 2-cm extra tendon is utilized for docking into the femoral tunnel.

An appreciation of the BF fibular insertional anatomy, as outlined by Branch and Anz, ¹ is surgically useful. The distal BF has 3 insertion sites on the fibular head: a proximal BF insertion, a distal BF insertion, and a medial BF insertion. The FCL fibular insertion is at the middle one-third of the fibular head and centered ~14.5 mm from the anterior fibular border.

A split in the iliotibial band (ITB) exposes the FCL femoral attachment site. A femoral tunnel is created at the native FCL insertion, sized per the diameter of the BF graft. The BF graft is transferred under the intact anterior BF tendon (BFT) and the ITB. If there is any concern about graft security on the fibular head, the distal FCL graft can be sutured to the stump of native FCL on the fibular head as well as the BF fibular tendon for security. Backup security can be done by placing a suture anchor into the fibular head and placing the sutures into the distal aspect of the BF rotated graft.

The BFT harvest site is closed with a running stitch. A Beath pin and passing suture are used to pull the graft into the femoral tunnel. Final graft fixation is done with the knee at 30° and an interference screw is placed in the femoral tunnel. We will now transition to the video demonstration of the procedure and focus on the FCL reconstruction segment.

The knee was positioned in flexion over a radiolucent triangle. Anatomic landmarks, including the fibular head, lateral femoral epicondyle, Gerdy's tubercle, and trajectory of FCL, were marked out.

A 10-cm curved incision was made from the fibular neck to the lateral femoral epicondyle and soft tissue flaps were developed. The interval between the BFT and the ITB was opened and FCL was identified. The FCL demonstrated a coronal tear with continuity, but it was functionally incompetent, as shown on arthroscopic examination demonstrating excessive lateral compartment gapping. The femoral insertion of the FCL on the lateral femoral epicondyle was palpated, and the junction of the upper and middle one-third of the ITB was split in line with its fibers, exposing the femoral insertion of the FCL.

Next, the BFT was identified, and the middle one-third of the tendon was longitudinally split, measuring the graft's width 8 mm and its length from insertion to the fibular head approximately 70 mm. A No. 2 abrasion-resistant suture was placed into the proximal end of the tendon graft.

The distal insertion of the BF to the fibular head was left intact, with care being taken to avoid convergence of tendon cuts as they extended toward the fibular head.

The proximal insertion of the FCL on the lateral femoral epicondyle was identified and released, and a No. 2 abrasion-resistant suture was placed on it. The BF graft was then passed underneath the ITB. The combined size of the native FCL and biceps tendon autograft was measured at 8 mm. A Beath pin was drilled from the FCL footprint, aiming anteriorly and superomedially toward the femoral cortex. An 8-mm reamer was used to create a 25-mm deep socket. The graft sutures were threaded through the Beath pin and pulled across to the medial femur. With the knee held at 30° of flexion and the foot in neutral rotation, slight valgus force was applied to the knee, the graft sutures were tensioned, and the combined grafts were secured in the femoral tunnel using a biocomposite screw. The graft harvest interval of the BFT and the ITB splits were repaired with an absorbable suture. The fibular end of the harvested graft was sutured to the intact native biceps tendon to avoid peel-off of the graft from the fibular head.

The incision was irrigated, the tourniquet was deflated, hemostasis was performed, and the subcutaneous and skin layers were closed in a regular fashion. The incision was dressed and the knee was placed into a knee immobilizer locked in extension.

Postoperatively, the patient is instructed on touch-down weightbearing with 2 crutches for the first 6 weeks. Initially, a knee immobilizer is used for full-extension positioning and after 2 weeks is transitioned to a long-legged hinged knee brace. Physical therapy is initiated after the first week, focusing on achieving full range of motion by 6 weeks. Partial weightbearing begins at 6 weeks, and strengthening exercises commence at 3 months. Return to sports is permitted after 6 to 9 months and depends on the presence of any additional concurrent injuries and progression of physical therapy. ⁶

Results and Discussion

There are no studies on outcomes available yet as this is a new technique. This procedure has been performed on 8 patients, but 2-year outcome data are not yet available. There have been no revisions of this procedure needed to be performed at this stage. We encourage further investigation into this technique.

We will now conclude by discussing pearls and pitfalls.

• The partial BFT autograft is an excellent option for FCL reconstruction or repair augmentation in a patient with FCL insufficiency. This is particularly important if the patient prefers not to use allograft or is in a limited resource setting.

• The ruptured FCL can be used to reinforce the reconstruction/augmentation in case the tissue has sufficient quality. Alternatively, the partial BF autograft can be used independently as a FCL graft.

• For a more anatomic placement of the FCL graft on the fibula, a suture anchor can be placed 8 to 9 mm from the anterior aspect of the fibular head with the FCL graft secured to the anatomic placement of the FCL on the fibula.

• In patients without peroneal nerve palsy, it may not be necessary to dissect the nerve around the fibular head, minimizing the risk of iatrogenic nerve injury.

• This technique avoids vascular injury due to the lack of fibular head tunnel placement.

• After retrieving the traction sutures on the medial femoral cortex, graft construct fixation can be enhanced by fixing it over a button.

• When dealing with a multiple ligament knee reconstruction, the FCL femoral tunnel should be directed proximally and anteromedially to avoid tunnel collision.

Below are our references for this presentation.

Thank you.