Proximal Tibiofibular Joint Stabilization With Concurrent Posterolateral Corner Reconstruction in Multiligamentous Knee Injury.

Proximal tibiofibular joint (PTFJ) instability is a rare knee injury, accounting for less than 1% of knee injuries. It causes significant lateral sided knee pain and functional deficits and can be associated with up to 9% of multiligament knee injuries. Concurrent surgical treatment of posterolateral corner (PLC) and PTFJ instability poses technical challenges due to the limited working space of the fibula head and inherent risk of collision between grafts, bone tunnels, and implants. In this Technical Note, we detail our senior author's technique for PTFJ reconstruction without the use of additional bone tunnels or implants in the fibula head, to reduce the risk of overcrowding and tunnel collision. CLASSIFICATIONS: Level I: knee; Level II: other, proximal tibiofibular joint.

Introduction

There are many methods described in posterolateral corner (PLC) reconstruction in the knee. These techniques usually involve graft fixation at the fibular head and are associated with favorable outcomes. Disruption of the proximal tibiofibular joint (PTFJ) can occur with posterolateral corner injury and becomes unstable for a fibula-based posterolateral corner reconstruction (PLCR). PTFJ injuries account for less than 1% of all knee injuries and is associated with up to 9% of multiligament knee injuries (MLKIs)., There are a number of techniques described for restoration of an isolated PTFJ instability. These include screw fixation, graft fixation, and suspensory device fixation.,, When PLC and PTFJ instability need to be addressed concurrently, a number of the described techniques for PTFJ stabilization are challenged. This is partly because of the limited working space, such as fibula bone availability and the risk of collision between grafts, bony tunnel, and implants during reconstruction in a MLKI.

In this Technical Note, we describe our senior author’s technique for PTFJ reconstruction that requires no additional bone tunnels or implants in the fibular head and reduces the risk of overcrowding and tunnel collision in the tibia.

Surgical Technique (With Video Illustration)

This PTFJ reconstruction technique is described in conjunction with a posterolateral corner reconstruction using a fibular head-based technique (Video 1). The pearls and pitfalls, as well as the limitations of this technique are presented in Tables 1 and 2, respectively.

Table 1

Pearls and Pitfalls for PTFJ Reconstruction Technique

Pearls	Pitfalls
Peroneal nerve neurolysis and decompression at its entry point into the peroneal compartment are important to prevent undue tension and also increase the working space.	There is limited working space due to size of fibula, graft in fibula head tunnel, and proximity to structures adjacent to the fibula head, such as peroneal nerve and biceps femoris.
Using the same fibula bone tunnel as the posterolateral corner reconstruction (PLCR) graft reduces the risk of collision between graft, bony tunnel, and implant in multiligament knee reconstruction.	Inadvertent injury to the peroneal nerve may occur.
Crossing one free end of each Ultrabraid interlocks the sutures. This configuration compresses the proximal tibiofibular joint (PTFJ) and counters anterior-posterior and proximal displacement.	Possible difficulty with positioning of the posterior suture anchor.
Placing suture anchors adjacent to fibular head and PTFJ ligaments replicates the native ligaments.	PTFJ reduction might not be accurately assessed.
Avoids damage to PTFJ articular surface.	Subsequent PLCR tensioning can potentially disrupt the PTFJR.
No additional graft is required.

Table 2

Limitations of PTFJ Reconstruction Technique

Failure to restore adequate proximal tibiofibular joint (PTFJ) stability affects the subsequent posterolateral corner reconstruction (PLCR) effectiveness.

This is a preliminary study, and further investigation is needed to establish the long-term benefits and efficacy.

PTFJ dislocation is not common and the clinical application is hence limited.

Positioning and Preparation

The patient is positioned supine and placed under general anesthesia. Examination under anesthesia is performed, assessing for PTFJ instability. This is done via moving the fibular head back and forth in an anterolateral to posteromedial direction to examine for laxity. A tourniquet of appropriate size is then applied onto the proximal thigh, and the patient is cleaned and draped.

A lateral incision with the knee in extension is made. This straight incision extends from 5 cm proximal to the lateral epicondyle, in between the Gerdy’s tubercle and fibular head, and 3 cm distal to these bony landmarks (Fig 1). The knee is flexed to 90°, and a full-thickness posterior flap is raised (Fig 2). The peroneal nerve is identified and neurolyzed. The nerve entry into the lateral leg compartment is decompressed. The fibular head is palpated and the stability of the PTFJ is reassessed (Fig 3). An incision adjacent to the anterior fibular head is made. This extends from the tip of the fibular head anterior to the lateral collateral ligament (LCL) to the fibular neck. The soft tissue attachment is cleared with a periosteal elevator. This is repeated for the soft tissue attachment on the posterior fibula head. The fibular tunnel is reamed and directed 30° in a posteromedial and proximal directions (Fig 4). The diameter of the fibular tunnel is predetermined from the PLC reconstruction graft diameter. The tibia adjacent to the fibular head is exposed for anchor fixation.

Fig 1

Surface marking on a left knee prior to proximal tibiofibular joint (PTFJ) reconstruction. The important landmarks such as lateral femoral condyle, Gerdy’s tubercle, and fibula head are denoted by white arrows. The lateral incision starts 5 cm proximal to the lateral epicondyle, extends between the Gerdy’s tubercle and fibula head to 3 cm distal to the level of the fibula head. The incision is made with the knee in extension.

Fig 2

Intraoperative photograph of a left knee. Following the incision, the knee is flexed to 90°, and a posterior full-thickness flap is raised. The important landmarks, such as fibula head, biceps femoris tendon, and peroneal nerve are identified. In this figure, the peroneal nerve is delineated by two yellow lines, the distal biceps femoris is represented by a white rectangle, and the proximal fibula is demarcated by the dotted white line. The peroneal nerve is neurolyzed and decompressed at its entry into the peroneal muscle compartment. This facilitates examination of the proximal tibiofibular joint stability and prevents undue tension to the nerve. The peroneal nerve is highlighted with a blue vessel loop round it.

Fig 3

Assessment of the proximal tibiofibular joint stability. The fibula head (within the white circle) is grasped firmly with the appropriate instrument, and an oscillating force is applied in an anterolateral to posteromedial direction.

Fig 4

Fibula tunnel direction. The anterior and posterior aspects (demarcated by white dotted lines) of the fibula head is exposed and the fibular tunnel is reamed in a 30° proximal and posteromedial direction (as indicated by the guide wire).

A proximal incision over the lateral epicondyle (LE) is made on the distal iliotibial band (ITB) along the direction of its fibers. The LCL and the popliteal tendon (PT) femoral attachment are identified. The two parallel femoral tunnels are reamed and directed 30° in an anterior and proximal direction.

Ultrabraid Sutures and PLCR Graft Passage, Tensioning, and Fixation

The Ultrabraid sutures (Smith & Nephew, London, UK) are first threaded through the fibular tunnel (Fig 5). The PLCR graft is then passed through the fibular tunnel. The two graft limbs are tunneled between the ITB and the joint capsule, and is pulled into their respective femoral tunnels. The LCL limb crosses superficial to the PT limb.

Fig 5

Threading the Ultrabraid sutures. (A) A wire loop (denoted by the white arrow) is threaded into the fibula tunnel via its anterior opening. (B) The Ultrabraid suture (denoted by black arrow) is threaded into the wire loop. (C) The suture is shuttled through the fibula tunnel by withdrawing the wire loop anteriorly. (D) The double folded anterior part of the Ultrabraid suture is cut to form two separate sutures.

The anterior limb of the first Ultrabraid suture is tunnelled in an anterior-to-posterior direction under the soft tissue on the lateral fibula head. Similarly, the posterior limb of the second Ultrabraid suture is tunnelled in a posterior to anterior direction under the same soft tissue bridge (Fig 6).

Fig 6

Positioning the two sutures around the fibula head. The anterior limb of the first Ultrabraid suture is tunnelled in an anterior-to-posterior direction under the soft tissue on the lateral fibula head. The same steps are repeated for the posterior limb of the second Ultrabraid suture in the opposite direction (from posterior to anterior).

The authors prefer to start with the posterior suture anchor for PTFJ stabilization. The site for the posterior suture anchor is on the tibia posterior and adjacent to the fibula head. It is located by palpation below the biceps femoris attachment to the fibula head. A 2.5-mm guide wire is used to determine the direction and level of suture anchor placement. The guide wire is directed 30° in an anteromedial direction at the same level as the tip of the fibula head and adjacent to the fibula head. The wire is initially directed 30° proximally to make a notch on the concave posterior tibia cortex. Its direction is then changed to parallel the tibiofemoral joint line. The guide wire subsequently directs the 5.5-mm cortex breaker and reaming is limited to a depth of 30 mm. The 2 free ends of the first Ultrabraid suture are then threaded through the 5.5-mm Footprint Ultra PK anchor (Smith & Nephew). The PTFJ is held in reduction with the Ultrabraid suture under tension and the posterior suture anchor is deployed (Fig 7).

Fig 7

Posterior suture anchor deployment. The posterior suture anchor is positioned on the tibia posteromedial to the fibula head at the level of the tip of the fibula head. (A) The guide wire is directed 30° in an anteromedial direction and followed by a 5.5-mm cortex breaker reamed to a depth of 30 mm. (B) The 2 free ends of the posterior Ultrabraid suture are loaded onto the Footprint Ultra PK anchor (Smith & Nephew). (C) The suture anchor is deployed.

For anterior fixation, the 2.5-mm guide wire is directed perpendicular to the tibia cortex adjacent to the fibula head at the level of the tip of the fibula head. A 5.5-mm cortex breaker is used and reaming is limited to a depth of 30 mm. The 2 free ends of the second Ultrabraid are threaded through another 5.5-mm Footprint Ultra PK anchor. The Ultrabraid suture is tensioned and the anterior anchor is deployed. (Fig 8) The stability of the reconstruction is checked. Fig 9 demonstrates the suture anchor position on pre-operative MRI imaging. Fig 10 demonstrates the overall schematic diagram of the PTFJ stabilization construct.

Fig 8

Anterior suture deployment. The guide wire is directed perpendicular to the tibia cortex adjacent to the anterior fibula head, and the suture anchor is similarly deployed.

Fig 9

MRI of left knee shown in axial (A), coronal (B), and sagittal (C) views demonstrating suture anchor position and technique for proximal tibiofibular joint (PTFJ) reconstruction. (A) Magnetic resonance imaging (MRI) of the left knee is shown in the axial view. The two white arrows indicate the positions of the suture anchors on the tibia. The fibula is at the posterolateral corner of the tibia and more posterior in the sagittal plane. It is potentially challenging to place the posterior suture anchor in the tibia adjacent to the fibula head. Dissection down to the tibia adjacent to the fibula head and posterior retraction of the soft tissue is required for accurate positioning and deployment of the suture anchors. (B) MRI of left knee is shown in the coronal view. The two white arrows indicate the boundaries of the PTFJ in the coronal plane. The suture anchor is deployed at the level of the tip of the fibula head (upper white arrow) to apply a perpendicular force to compress the PTFJ. (C) MRI of left knee is shown in the sagittal view. The white arrows indicate the concavity of the posterior cortex of the proximal tibia at the region of the PTFJ. The guide wire is initially angled 30° proximally to notch the cortex before changing its direction to be parallel to the tibiofemoral joint surface.

Fig 10

Proximal tibiofibular joint (PTFJ) reconstruction suture loop schematic demonstrated on magnetic resonance imaging of the left knee axial view at the level of the fibula head. The blue rectangle represents the fibula head tunnel directed in 30° posteromedial and proximal directions. The 2 Ultrabraid sutures are represented by the red and white dotted lines. The white arrows indicate the positions of the anterior and posterior suture anchors. The free ends of each length of Ultrabraid suture are paired. The anterior limb of the first (white) loop is tunneled posteriorly under the soft tissue attachment on the lateral fibula head. The posterior limb of the second (red) loop is tunneled anteriorly under the same soft tissue layer. Each loop is tensioned by deployment of the suture anchor and counters the displacement of the fibula head in the anterolateral and posteromedial direction. The 2 loops are interlocked and this configuration compresses the reduced PTFJ.

The fibula screw is subsequently deployed. The knee is in 90° of flexion and neutral rotation under valgus stress. The PT limb is tensioned and the femoral screw is deployed. The knee is then extended to 20° in neutral rotation under valgus stress. The LCL limb is tensioned and the femoral screw deployed. The stability of the reconstruction is checked. The wound is copiously irrigated and haemostasis checked. The ITB is repaired and the wound closed in layers. A knee brace is applied and locked at full extension. The neurovascular status of the limb is checked.

Reconstruction for Isolated PTFJ Injuries

For isolated PTFJ reconstruction, a less extensive exposure and dissection is required in the region of the fibular head and a fibula tunnel of smaller diameter is required.

Postoperative Rehabilitation

The surgery requires less than 24-hour inpatient stay. The patient is instructed passive range of motion as tolerated and kept non-weightbearing for six weeks post-surgery. Weight bearing and active range of motion are started after 6 weeks. Good pain control is important for effective mobilization and strengthening. Patients typically are able to return to running by 6 months after surgery.

Discussion

There are a number of techniques described for isolated PTFJ stabilization and good outcomes had been reported. These include as screw fixation, graft reconstruction, and suspensory device fixation.5, 6, 7 There are challenges in PTFJ stabilization when it is concurrent with MLKI reconstruction. When there is PLCR, the graft in the fibula head tunnel limits the working space. Additional implants in this region pose a potential risk of fracture. When there are anterior cruciate ligament and posterior cruciate ligament reconstructions, the tibia tunnels might collide with the trajectories of the implants used for PTFJ stabilization.

The described technique addresses the limited working space of the fibula by using the same bony tunnel in the fibula head as the PLCR. It reduces the risk of collision of bone tunnels, graft, and implant trajectories in the tibia during a MLKI reconstruction.

Using Ultrabraid sutures minimizes the bony space required in the fibula head. Ultrabraid or a suture of similar strength is preferred. The free ends of the Ultrabraid suture are crossed to effectively reduce the PTFJ. The posterior suture anchor aims to control anterior translation and vice versa for the anterior suture anchor. Each length of Ultrabraid forms a loop. By crossing one end of each Ultrabraid over the other, it interlocks. This configuration provides multiplanar stabilization in anterolateral and posteromedial translation, as well as anteromedial compression to reduce the PTFJ.

No additional graft is required, and the PTFJ articular surface is not violated. The suture anchor enables fixation close to the native ligaments to replicate the static stabilizers. The anchors require comparatively less tibia bone space compared to other described techniques. The direction of the suture anchors is preferably parallel to the tibia articular surface to avoid damaging it. The use of a syringe needle helps to locate the joint lines of the PTFJ and lateral tibiofemoral joints and guides positioning of the suture anchors.

This technique is also applicable to isolated PTFJ instability. In this context, it requires comparatively less exposure and smaller fibula bone tunnels. Passive flexion and no weight-bearing are advised for 6 weeks after surgery to reduce the strain on the stabilized PTFJ.

Conclusion

PTFJ stabilization is challenging in MLKI reconstruction. This is due to limited working space of the fibula head and inherent risk of collision between grafts, bone tunnels, and implants. This Technical Note presents a surgical technique for PTFJ instability that addresses these concerns and provides multiplanar stabilization for the PTFJ.