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Surgery for posterolateral corner injuries (part 5 of a course on the posterolateral corner)

I discussed in Part 3 that the indication for surgical management of PLC injuries is a third-degree injury in which there are ruptures to the FCL, MPTL, and posterolateral capsule.

In some instances, patients may have a chronic severe rupture to the FCL, but only minor damage to the other PL soft tissues. However, they have frequent instability that must be treated with surgery.

Preoperative considerations

There are different surgical techniques for the PLC, which are chosen based on the severity of injury and quality of tissues.

In Part 4, we went through the treatment for acute and chronic injuries to the PLC, including the timing of surgery according to the condition of the lower limb and knee joint. In this section, we will assume that the patient has received the appropriate preoperative rehabilitation and medical care to prepare them for the operation. The knee range of motion should be full or nearly normal, swelling should be minimal at the most, the patient should be able to walk normally, and the muscle strength should be good with the patient able to elicit a strong quadriceps contraction. If the patient had a bowed-leg malalignment, this should have already been treated with a high tibial osteotomy to realign the lower limb to normal.

If the patient is to undergo an ACL or PCL reconstruction along with the posterolateral procedure, then the options for grafts should be discussed before surgery. I prefer autograft tissue (from the patient’s own knee) with bony fixation, such as in a patellar tendon graft. However, I make sure that patellar tendon and Achilles tendon allografts are available the day of surgery. These will be required if autogenous tissue are unavailable or not suitable for the ligament reconstructive procedures. The patient is aware of this and provides consent to use allograft tissue if necessary.

Evaluation at surgery

After the patient has been put to sleep, all of the knee ligament tests that were done in the clinic are again performed in both the injured and contralateral limbs. This is done to be sure that we did not miss an important ligament problem because the patient had difficulty relaxing during the clinical examination. The gap test is done, as I described in Part 2, to measure the amount of lateral joint opening during the arthroscopic examination under a small amount of force. We look at all of the joint surfaces (kneecap, femur, tibia) to see if arthritic damage is present, which is documented. We carefully assess the ACL, PCL, medial meniscus, and lateral meniscus and look for damage, even if it is minor.

Then, we make our initial incision and inspect all of the posterolateral structures to look for tears and to determine the quality of the tissues. This is critical in finally determining the appropriate surgical procedure to perform. The peroneal nerve is identified and protected throughout the operative procedure.

Fibular collateral ligament procedures

Anatomic reconstruction

In cases where the FCL is completely deficient, especially in chronic knees where only scar tissue exists in place of the ligament, an anatomic reconstruction is required. The goal of a FCL anatomic reconstruction is to use a strong graft to completely replace the ligament, which is attached by bone to anatomic insertion sites on the femur and fibula. I prefer to use a patellar tendon autograft, which can be harvested from either the injured or contralateral knee. Autografts generally heal faster than allografts, with a small complication rate of less than 1% in terms of infection, scar formation, and graft site pain. If the patellar tendon cannot be used from either knee (in cases where it was used in another operation, or might be used for the ACL reconstruction), then a patellar tendon allograft is the next option. An Achilles tendon allograft or quadriceps tendon autograft may be used, but these grafts only have bone on one end for fixation to either the femur or fibula.

The attachment site of the patient’s FCL on the femur and fibular are identified. A tunnel is drilled in the fibula and then in the femur, as shown in the Figure.

fibular collateral ligament reconstruction

[This article was published in Noyes’ Knee Disorders: Surgery, Rehabilitation, Clinical Outcomes, Noyes FR, Barber-Westin SD (eds.), Copyright Saunders, 2009 - Noyes FR, Barber-Westin SB: Posterolateral ligament injuries: Diagnosis, operative techniques, and clinical outcomes, pages 577-630.]

The bone portion of the graft is gently placed into the fibular tunnel and is held in place with two small fragment screws. The graft is advanced through the knee into the femoral tunnel and fixed with a soft tissue interference screw.

A, two small fragment screws are used to fix the bone into a slot created in the proximal fibula. Interference screw fixation is used at the femoral anatomic site of the FCL.

B, a fibular tunnel is made, graft seated, and an interference screw is used for fixation.

Femoral-fibular reconstruction

Another surgical option, which is especially indicated in acute, dislocated knees where I am trying to keep the operative time to a minimum (because multiple ligaments have to be reconstructed), is what is termed a femoral-fibular reconstruction. Here, the FCL is present, but is lax which allows an abnormal amount of increased lateral joint opening and tibial rotation. The PMTL does not require graft substitution. A large allograft is placed in a circular fashion around the existing FCL, as is shown in the Figure.

Femoral-fibular reconstruction

A, placement of femoral and fibular tunnels and FCL graft.

C, suturing and tensioning of graft arms.

E, multiple sutures used through both arms of graft and the slack FCL. Plication of the posterolateral capsule is performed to the graft.

[This article was published in Noyes’ Knee Disorders: Surgery, Rehabilitation, Clinical Outcomes, Noyes FR, Barber-Westin SD (eds.), Copyright Saunders, 2009 - Noyes FR, Barber-Westin SB: Posterolateral ligament injuries: Diagnosis, operative techniques, and clinical outcomes, pages 577-630.]

Popliteus muscle-tendon-ligament unit procedures

Repair

In cases where partial PMTL function exists, an advancement (tightening) of these tissues may be performed without graft substitution. The popliteal tendon is advanced at its femoral attachment site, which restores normal tension in the entire structure.

Graft replacement

When the PMTL is deemed completely nonfunctional because the distal attachments are disrupted or replaced with scar tissue, a graft reconstruction is required as is shown in the Figures below. For this technique, I prefer to use an Achilles tendon-bone allograft, with the bone portion of the graft placed at the anatomic femoral insertion site and the collagenous portion of the graft passed in the tibial tunnel.

PMTL graft replacement

A, location of posterolateral tibial tunnel and graft passage. A soft tissue interference screw and suture post are used for tibial fixation of the popliteus graft.

B, passage of popliteus graft beneath the FCL patellar tendon graft.

popliteus and fcl grafts

C, final fixation of the popliteus and FCL graft reconstructions.

F, suture of popliteus graft to posterior margin of the FCL graft at the fibular attachment site to restore the popliteofibular ligament.

H, suture plication of posterolateral capsule to posterior margin of the FCL graft.

[This article was published in Noyes’ Knee Disorders: Surgery, Rehabilitation, Clinical Outcomes, Noyes FR, Barber-Westin SD (eds.), Copyright Saunders, 2009 - Noyes FR, Barber-Westin SB: Posterolateral ligament injuries: Diagnosis, operative techniques, and clinical outcomes, pages 577-630.]

Posterolateral capsule procedures

Graft reconstruction for severe varus recurvatum and hyperextension

In patients who demonstrate 15° or more of knee hyperextension, severe deficiency exists of the entire posterior capsule and oblique popliteal ligament in addition to possible cruciate, FCL, and PMTL damage. In these severe knee injuries, a PMTL reconstruction alone will not block a severe varus recurvatum deformity. A posterolateral capsular graft reconstruction is required in addition to a graft reconstruction of the PMTL and FCL. This is done with an Achilles tendon allograft in a manner similar to that used for the PMTL reconstruction. The bone portion of the graft is placed by the lateral gastrocnemius tendon origin with a femoral tunnel – the fixation is accomplished with two small fragment cancellous screws and washers or with an interference screw. The graft lies along with posterolateral capsule and is passed through the tibial tunnel. Here, the tendon portion of the graft is fixed and the knee hyperextension and varus recurvatum at this point should be resolved. Postoperatively, the graft may stretch slightly; the goal is to have 0° to -2° of hyperextension.

Proximal advancement for minor posterolateral deficiency

In some knees, chronic insufficiency of the PL structures exists from a minor injury (without complete traumatic ligament disruption). A definitive FCL of normal width and integrity (although lax) is identified at surgery and the PMTL attachments are intact although elongated (stretched out). These patients do not require a large graft replacement procedure. Instead, the PL structures may be advanced proximally in a more simplified operative procedure. This procedure is frequently done with a high tibial osteotomy or cruciate ligament reconstruction when the tissues are deemed to be intact after careful inspection at surgery. The procedure is demonstrated in the Figures below.

proximal advancement

B, the posterolateral structures are identified and have a normal appearance, although lax. The line for the osteotomy of the femoral attachment of the FCL, PMT, and anterior portion of the gastrocnemius tendon is shown.

C, D, the osteotomy is 8 mm deep to provide sufficient bone to maintain the attachments of the FCL, popliteus tendon, anterior gastrocnemius tendon, and posterolateral capsule. The posterolateral capsule is incised 15 mm in length.

graft fixation

F, the bone attachment of the posterolateral structures is advanced proximally in line with the FCL, with the knee in neutral tibial rotation and 30° flexion. Reattachment of the bone is achieved with a four-pronged staple and screw.

[This article was published in Noyes’ Knee Disorders: Surgery, Rehabilitation, Clinical Outcomes, Noyes FR, Barber-Westin SD (eds.), Copyright Saunders, 2009 - Noyes FR, Barber-Westin SB: Posterolateral ligament injuries: Diagnosis, operative techniques, and clinical outcomes, pages 577-630.]

Updated: 06 May, 2013
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