Repair of Posterior Cruciate Ligament Femoral Avulsion in Multiligament Knee Injuries

Abstract

Background:

In patients with multiligament knee injuries (MLKIs), arthroscopic primary repair of the posterior cruciate ligament (PCL) can be considered for proximal soft tissue avulsion or femoral “peel-off” injuries. The advantages of PCL repair include preservation of native anatomy, providing better proprioception and earlier rehabilitation, as well as a lower risk of tunnel convergence.

Indications:

We discuss 2 cases of MLKIs with acute femoral soft tissue avulsion of the PCL.

Technique Description:

The first case involves a complete PCL femoral avulsion with concomitant anterior cruciate ligament (ACL) and medial collateral ligament (MCL) tears. Outside-in femoral tunnel drilling for the PCL femoral tunnels was used to prevent convergence with the MCL footprint on the medial femoral condyle. The second case involves a proximal tear of the PCL with concomitant ACL tear and posterolateral corner injury. In this case, the femoral tunnels were drilled from inside-out.

Results:

The postoperative clinical examination shows restoration of knee stability, while magnetic resonance imaging 6 months after surgery demonstrates intact ligament repair and reconstruction.

Discussion/Conclusion:

The literature has shown no significant difference in clinical outcomes when comparing primary repair of PCL femoral avulsion with PCL reconstruction in MLKIs. With careful patient selection and surgical planning, primary repair of PCL femoral avulsion in MLKIs shows good knee stability, good patient satisfaction, and promising clinical outcomes.

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 journal discusses the surgical technique for primary repair of posterior cruciate ligament (PCL) femoral avulsion in multiligament knee injuries (MLKIs).

We have no disclosures.

Background

An MLKI involves tears of at least 2 major knee ligaments. ⁸ These complex injuries are rare and often arise from knee dislocations. ⁷

Studies have shown that operative treatment leads to improved outcomes,^7,8 and early surgery promotes better functional recovery.^6,7 There is no definitive consensus with regards to repair versus reconstruction, although studies have shown comparable outcomes between primary repair and reconstruction in combined anterior cruciate ligament (ACL)–PCL injuries.^3,7

For this study, we focus on proximal PCL avulsion or femoral “peel-off” tears, where arthroscopic primary repair is a treatment option. ¹³ Unlike the ACL, the PCL is larger and has better blood supply, allowing primary healing. ¹⁰ A predictor of successful PCL repair is a distal stump length of at least 41 mm. ⁵

The advantages of arthroscopic PCL repair include preserving the native PCL, achieving better proprioception, and allowing earlier rehabilitation. ⁶ With repair, the risk of tunnel convergence is decreased.^8,11 It is less time-consuming ¹³ and allows for easier reconstruction revision surgery if needed. ⁶

Indications and Technique Description

For this study, surgical indications include acute MLKI with grade III knee laxity involving femoral “peel-off” tears ¹⁰ with a distal stump length of at least 41 mm based on preoperative magnetic resonance imaging (MRI).^5,12

Our first patient was a 58-year-old man with a right knee injury after getting hit by a vehicle while crossing the street. The MRI showed a complete ACL tear, PCL femoral avulsion, and proximal medial collateral ligament (MCL) tear. The distal stump of the PCL appears to have good tissue bulk, making it amenable for primary repair.

On clinical examination, the right knee had a positive Lachman test, a positive posterior drawer test and posterior tibial sag, and valgus laxity on knee extension and at 30° of flexion.

A single-stage arthroscopic procedure was planned within 2 weeks of the injury. The goal was anatomic restoration of the ligaments to correct instability and optimize function. Primary PCL repair will be achieved using high-strength sutures. The PCL tunnels will be drilled from outside-in to ensure that they do not converge with the MCL footprint. This will be followed by ACL reconstruction, then MCL repair.

The patient was positioned supine with the right knee hanging off the table at 90° of flexion, allowing access to the surgical site. The left leg was kept out of the surgical field with a leg holder.

Standard anterolateral (AL) and anteromedial portals were created. The ACL and PCL femoral avulsions were noted to have good tissue quality. The PCL distal stump was mobilized and assessed. Posterior tibial subluxation was reduced to avoid any false assessment of distal stump length.

Once confirmed repairable, high-strength sutures were passed through the PCL stump using an antegrade suture passer. Multiple sutures were placed at various points of the stump to ensure full footprint coverage while carefully checking for resistance to avoid perforating previously placed sutures. A total of 6 sutures, in both simple and luggage tag configurations, were used.

An incision was made on the medial knee to identify the MCL femoral insertion. ⁹ Two double-loaded suture anchors were placed over the MCL footprint for the repair. This facilitates placement of the outside-in PCL femoral guide bullet on a point away from the MCL insertion and repair anchors.

Viewing from the AL portal, both AL and posteromedial (PM) bundle landmarks of the PCL footprint were identified. The guide was centered over each bundle footprint via the anteromedial portal, and 4.5-mm tunnels were reamed from outside-in. We aim to reproduce anatomic PCL bundles covering the entire footprint.

Using a passing suture, 3 pairs of repair sutures were shuttled through each tunnel on the AL and PM bundle footprints. The distal stump was tensioned with the knee in 90° of flexion and an anterior drawer force applied to reduce the tibia. The suture ends were simultaneously tensioned and tied over the bony bridge between the drill holes, securing the PCL repair. Stability was confirmed by applying a gentle posterior drawer force while visualizing the integrity of the repair.

For the ACL, we had difficulty bringing the remnant stump toward its femoral footprint. Reconstruction using a hamstring autograft from the ipsilateral limb was then performed.

The MCL repair was completed using multiple suture anchors, which strengthens the repair while providing good coverage of the MCL footprint. This successfully restored medial knee stability.

At 1 year postsurgery, the patient's knee range of motion (ROM) was similar to the uninjured side, posterior sag was negligible, there was no valgus laxity, and both anterior drawer and Lachman tests were negative. The patient had no pain or instability. This single-stage combined repair and reconstruction of ACL, PCL, and MCL provided good patient satisfaction while using a single hamstring autograft.

The next case is a 36-year-old man with a right knee injury after an object weighing more than 300 kg landed on his knee. The MRI showed a complete ACL tear, a high-grade partial tear on the proximal PCL, and avulsion of the lateral collateral ligament (LCL), biceps femoris tendon, and lateral capsule. The distal PCL stump appeared to have good soft tissue bulk.

On clinical examination, the right knee had a positive Lachman test and varus laxity on knee extension and at 30° of flexion. Posterior tibial sag was positive.

A single-stage arthroscopic procedure was planned within 1 week of the injury. For this case, PCL tunnels will be drilled from inside-out. This will be followed by ACL reconstruction, then posterolateral corner (PLC) repair. The same surgical setup, equipment, and instrumentation were used.

Some remnant of the PCL was noted over the femoral footprint. Despite some fraying on the proximal end of the PCL distal stump, it had good tissue quality and adequate length for primary repair. A complete ACL tear was confirmed.

Using an antegrade suture passer, the first suture was passed through a good distal stump. All 4 sutures were placed in luggage tag configuration.

This technique differs from the previous case, as the AL and PM PCL tunnels were drilled from inside-out using the femoral footprint as a guide. This was done by viewing from the AM portal and drilling from the AL portal.

The repair sutures were shuttled through the PCL femoral tunnels. The distal stump was tensioned and secured while reducing the knee with anterior drawer force. An ACL reconstruction was performed using a tibialis anterior allograft.

The repair of posterolateral knee structures was performed through an open lateral approach, ensuring the common peroneal nerve was identified and protected. Multiple suture anchors were used to repair the lateral capsule, distal LCL avulsion, and biceps tendon avulsion from the fibula, restoring lateral knee stability.

At 6 months postsurgery, the patient's knee ROM was similar to the uninjured side, the anterior drawer test was negative, both posterior drawer test and posterior sag were negative, and there was no varus laxity. Postoperative MRI showed intact PCL repair with signs of healing. The ACL graft and PLC repair were also intact. The PCL tunnels are traced with red broken lines. This single-stage combined repair and reconstruction of ACL, PCL, and PLC successfully restored knee stability.

Results and Discussion

The following are surgical tips for PCL repair in MLKIs: a critical time period of 2 to 3 weeks allows for soft tissue delineation and reapproximation.^7,8 Careful patient selection is crucial. Adequate distal stump length and tissue quality are key factors for successful PCL repair.^1,5,12 A comprehensive preoperative plan should always include possible ligament reconstruction if needed.

During tunnel preparation, we should aim for 2 femoral tunnels separated by an adequate bone bridge. ⁴ An outside-in drilling technique can prevent convergence with the MCL footprint in the setting of a PCL-MCL injury.

For the postoperative rehabilitation, a knee brace locked in extension was applied immediately after surgery and replaced by a dynamic PCL brace after suture removal. This was worn for 6 months. Weightbearing, knee ROM, and strengthening exercises were progressed gradually. Jogging was allowed once limb strength symmetry had recovered. Return to sports or full recreational activities was generally expected after 12 months from surgery.

In 2002, the first case series on arthroscopic repair of PCL femoral avulsion in MLKIs was presented. At 4 years, all patients returned to their preinjury level of activity and sports. Their mean Lysholm score was 95.4. ¹³

In this cohort and meta-analysis, good and excellent postoperative results were achieved by suture repair. No difference was found in functional outcomes when comparing primary suture repair and reconstruction of combined ACL-PCL injuries. ⁷ This supports our decision to perform PCL repair in both cases.

With regards to the choice of ACL surgery in the setting of a PCL repair, this retrospective study shows that ACL reconstruction with PCL repair had superior anterior objective knee stability compared to ACL repair with PCL repair. ² This supports our preference for ACL reconstruction in both cases.

Conclusion

Arthroscopic primary repair of the PCL is a treatment option, especially in proximal soft tissue avulsion or femoral “peel-off” tears. Careful patient selection, including assessment for sufficient PCL distal stump, is critical in the success of the repair. In combined PCL-MCL injuries, outside-in femoral drilling for the PCL tunnels prevents convergence with the MCL footprint. The functional outcomes of primary PCL repair are good, with no significant difference when compared to PCL reconstruction.