Open Approach for Repair of Tibial PCL Avulsion

Abstract

Background:

Tibial avulsion of the posterior cruciate ligament (PCL) often requires operative fixation, which frequently results in successful outcomes if identified acutely. Open or arthroscopic techniques are most commonly used.

Indications:

Primary surgical indications for open fixation include acute tibial avulsion of the PCL. Secondary indications include grade 2 to grade 3 posterior drawer test and radiographic posterior subluxation of the tibia. Ideally, the joint space and articular cartilage should be well preserved.

Technique Description:

In the simplified approach initially described by Burks and Schaffer, the patient is placed prone, and an inverted L-shaped incision is made over the posteromedial corner of the knee. A plane is developed between the medial head of the gastrocnemius and the semimembranosus down to the knee joint capsule. The gastrocnemius is retracted laterally to protect neurovascular structures and a vertical capsulotomy is performed. The tibial attachment of the PCL is reduced and held with K (Kirschner) wires and then fixated with screw and washer.

Results:

Six months post operation, our patient achieved full active and passive range of motion with a stable posterior drawer test. He returned to work without difficulty. Multiple studies have shown success with open PCL fixation and decreased rates of arthrofibrosis when compared with arthroscopic approach. In this case, the patient did not develop arthrofibrosis.

Discussion/Conclusion:

PCL tibial avulsions can be safely treated with an open approach. Contrary to other ligaments that favor reconstruction over repair, PCL avulsions may be better treated with early repair, so it is important to avoid delay in intervention. The most common complication in both open and arthroscopic approaches is arthrofibrosis, which is less common in the open approach. Early range of motion is encouraged to prevent arthrofibrosis.

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 discuss an open approach for repair tibial posterior cruciate ligament (PCL) avulsion. The authors have no disclosures to declare.

This is a case of a 16-year-old male involved in a motorcycle accident. He sustained a left midshaft femur fracture as well as a PCL avulsion and a grade 2 medial collateral ligament (MCL) injury. On his presentation, he was neurovascularly intact and underwent semi-urgent femoral shaft fixation and was referred to clinic within 1 week for persistent posterior instability of the knee despite bracing. He had no significant past medical history and no prior knee injuries.

Initial radiographs at the time of injury are subtle but demonstrate a small PCL avulsion off of the posterior tibia. The medial and lateral compartments appear congruent, but there is subtle posterior subluxation of the tibia under the medial femoral condyle. The coronal computed tomography (CT) scan demonstrates a displaced avulsion of the PCL off of the tibia. The axial cut clearly demonstrates that the isolated fragment is predominantly PCL, with no involvement of the articular cartilage. On the sagittal series, you can see posterior subluxation of the medial tibia under the medial femoral condyle and further evidence of displacement of the PCL avulsion fragment.

Treatment of tibial-sided PCL avulsions is highly dependent on the acuity of the injury. Injuries identified within a 2- to 6-week timeframe can often be treated with an acute surgical repair. Surgical consideration should be made when an injury has an associated grade 2 to grade 3 posterior drawer as well as radiographic evidence of posterior subluxation of the tibia. Furthermore, surgical treatment should be limited to joints that are otherwise well preserved.^3,4,6,7

When considering surgical repair, there are multiple options. You can do open versus arthroscopic repair. You should also consider treatment of concomitant ligamentous injuries such as anterior cruciate ligament (ACL), MCL, and posterolateral corner injuries. Repair versus reconstruction should also be considered though the literature would favor acute repair if possible. However, reconstruction options are available should an injury be found in a delayed fashion. Degree of displacement should be considered. When fragments are displaced over centimeters, this is often associated with ligamentous instability.^2,3,5 Appropriate imaging should be considered as well, including CT scan for assessment of displacement if minimally displaced on a plain radiograph. Magnetic resonance imaging (MRI) should also be considered but should not delay surgical intervention.

When planning and positioning, fixation can often be achieved with a simple cortical screw or cancellous screw with washer. Small, smooth Kirschner wires (K wires) should be available for provisional reduction, and the room should be prepared with a big fluoroscopy C arm. Retractors include an appendiceal, a small Hohmann, and a dental pick. The advantages of the open approach are the simplicity in set up and ease of approach and access. Patients are positioned prone with the general endotracheal sedation with a popliteal nerve block. A nonsterile tourniquet is used inflated to 250 mm Hg and patients are pre-dosed with 2 g of Ancef prior to incision.

An examination under anesthesia is performed. There is evidence of slightly asymmetric hyperextension of the injured knee. On examination, there is a firm endpoint with valgus in full extension, but loss of rebound and asymmetric laxity with valgus at 20° of flexion consistent with a grade 2 injury. There is no injury to the posterior lateral corner or lateral ligamentous complex. The ACL has a firm endpoint with Lachman. There is clear posterior subluxation of the tibia with a posterior drawer, which is grade 3. There is no locking or catching of the knee with passive flexion or extension of the knee.

A posterior approach to the knee as initially prescribed by Burks and Schaffer ¹ is used. The patient is positioned prone and an inverted L-shaped incision is made. The horizontal limb of the incision is placed in the flexion crease of the knee, and the vertical limb is on the medial side just along the medial edge of the gastrocnemius muscle. Full-thickness flaps are made medially and laterally. The pes anserine tendons can be identified in the superficial fascia, and a plane is developed between the pes tendons and the medial gastrocnemius muscle. The semitendinosus muscle is identified superficially, and the semimembranosus muscle is identified just deep to this. An appendiceal retractor is used to retract the medial head of gastrocnemius to expose the posterior capsule. A blunt Hohmann can be used to retract the semimembranosus medially to further expose the capsule. The posterior capsule is identified and a planned zone for capsulotomy is made. A vertical capsulotomy is made and extended with sharp dissection. The fracture bed is encountered, and the fracture fragment is mobilized to allow for the removal of fracture debris fragments and fracture hematoma. The fracture is provisionally reduced with a dental pick and held with 2 Kirschner wires. Reduction is confirmed with lateral fluoroscopic imaging. Final fixation is achieved with a single 4-0 cancellous screw with washer. Final fluoroscopic images demonstrate anatomic reduction and appropriate screw placement. Note that the screw does not need to be bicortical.

Postoperatively, patients are kept toe-touch weightbearing for 6 weeks. Physical therapy typically starts early within 1 to 2 weeks. Patients are locked in an extension hinged knee brace for 2 weeks and then flex unlocked in a hinged knee brace. We typically prescribe aspirin 81 mg twice a day for deep vein thrombosis (DVT) prevention for 2 weeks. A return to sport typically takes around 3 to 6 months. At 6 weeks postoperatively, the patient is able to demonstrate passive range of motion to 125° and maintain full extension. He had a stable Lachman as well as posterior drawer and no coronal laxity with varus or valgus stress. Radiographs demonstrated no loss of fixation.

At 6 months, the patient had full active and passive range of motion symmetric to the contralateral knee with a stable ligamentous examination. The femur fracture was well healed and clinically he returned to 100% normal and went back to work without difficulty. Radiographs demonstrated a well-healed fracture. On follow-up examination, he is able to demonstrate no laxity with posterior drawer and is symmetric to the contralateral knee.

In a systematic review comprised of 20 articles and 637 patients, Hooper et al² found that 59% of these injuries occurred from motorcycle accidents. Patients had similar postoperative Lysholm knee scores ranging from 95 arthroscopic compared to 93 open. Arthrofibrosis was common and ranged from 0% to 35%. ²

In conclusion, PCL tibial avulsions can be safely treated with open approaches. Arthrofibrosis remains a common complication, slightly more common in arthroscopic cases. The advantage of an open approach allows for more robust fixation and consequently earlier range of motion safely.^2,5 Earlier range of motion is encouraged to prevent this complication and avoid delays in intervention by treating fractures more acutely. Contrary to other ligaments that may favor reconstruction over repair, PCL avulsions may be better treated with early repair.