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Injuries to the posterior cruciate ligament (PCL) can range from ligament tears to fractures in which the ligament pulls away a piece of bone from its attachment on the tibia. This latter injury is known as a PCL tibial avulsion fracture.
When the displaced bone fragment affects knee stability, restoring its position and securing it may be necessary to help recover normal knee function.
A 2021 case report from Singapore described an arthroscopic technique for treating a displaced PCL tibial avulsion fracture using a modular suspensory fixation construct. The technique was developed to provide compression and stabilisation of the displaced bone fragment while avoiding some of the challenges associated with traditional fixation methods.
The research was authored by Joel Lee Zhao Jie and Dr Wang Lushun. Dr Wang Lushun of Arete Orthopaedic Centre was affiliated with the Department of Orthopaedics at Ng Teng Fong General Hospital, Singapore, at the time of the research and was the corresponding author.
Importantly, this was a single-patient case report, so the findings describe the technique and outcome in one patient rather than establishing its effectiveness for all PCL avulsion fractures.
What Is a PCL Tibial Avulsion Fracture?
The posterior cruciate ligament is one of the major ligaments inside the knee. It helps prevent the tibia from moving excessively backwards relative to the femur and contributes to overall knee stability.
A PCL tibial avulsion fracture occurs when the PCL pulls away a fragment of bone from its attachment on the tibia.
Rather than the ligament simply tearing within its substance, the injury involves the bone where the ligament attaches.
A displaced bone fragment can affect the mechanical stability of the knee and may require anatomical reduction and fixation. The authors noted that displaced PCL tibial avulsion fractures can result in knee instability and often require fixation to restore function.
How Can a PCL Avulsion Fracture Happen?
These injuries can occur during significant trauma, including:
- Motorcycle or vehicle accidents
- Falls
- Sports injuries
- High-impact trauma
The research case involved a 42-year-old man who sustained the injury in a motorcycle accident. Imaging showed that the displaced bone fragment measured approximately 3.1 cm × 2.6 cm × 1.5 cm.
What Symptoms Can a PCL Avulsion Fracture Cause?
Symptoms can vary depending on the severity and displacement of the fracture.
Potential symptoms include:
- Knee pain
- Swelling
- Difficulty bearing weight
- Reduced knee movement
- A feeling of instability
- Difficulty returning to normal activities
Because the injury involves both the PCL attachment and a bone fragment, an accurate diagnosis is important for determining the appropriate treatment.
How Is a PCL Tibial Avulsion Fracture Diagnosed?
Diagnosis generally involves a combination of clinical assessment and imaging.
Medical History
The doctor may ask:
- How the injury occurred
- Whether the knee twisted or was struck
- Whether swelling developed immediately
- Whether the knee feels unstable
- Whether weight-bearing is possible
Understanding the mechanism of injury can provide clues about which structures may have been damaged.
Physical Examination
A knee specialist may assess:
- Range of motion
- Stability
- Swelling
- Tenderness
- Movement of the tibia relative to the femur
Imaging
X-rays can identify the presence and displacement of a bone fragment.
Additional imaging may be used to provide more information about:
- The size of the fragment
- Its position
- Associated ligament injuries
- Other damage within the knee
Why Can Displaced PCL Avulsion Fractures Require Fixation?
The objective of treatment is generally to restore the displaced bone fragment to its anatomical position and stabilise it so that healing can occur.
Leaving a significantly displaced fragment untreated may result in persistent instability or altered knee mechanics.
The researchers noted that displaced PCL tibial avulsion fractures often require anatomical reduction and fixation to restore function.
The appropriate treatment, however, depends on factors such as:
- Fragment displacement
- Fragment size
- Knee stability
- Associated injuries
- Patient activity level
Traditional Approaches to PCL Avulsion Fracture Fixation
Historically, displaced PCL avulsion fractures have been treated using different fixation techniques, including open surgical approaches and various arthroscopic methods.
Open posterior approaches can provide direct access to the fracture but require working around important structures located behind the knee.
Arthroscopic techniques offer a less invasive alternative and allow the surgeon to visualise the joint through small portals.
However, fixing a fragment located at the posterior tibial attachment of the PCL presents technical challenges because of its anatomical position.
What Technique Did the Research Describe?
The 2021 report described a modular suspensory fixation technique performed arthroscopically.
The approach used a modified double Endobutton construct to secure the displaced bone fragment.
The authors developed the technique as a modification of an established transtibial all-inside Endobutton approach.
Step 1: Arthroscopic Assessment
The procedure began with standard arthroscopic portals and an additional posteromedial portal.
This allowed the surgeons to:
- Visualise the knee joint
- Identify the displaced PCL fragment
- Assess the fracture
- Prepare for reduction
Step 2: Reduction of the Bone Fragment
The displaced fragment was reduced using a tibial PCL drill guide.
A 2.4-mm guidewire was then used to temporarily hold the fragment in position.
The objective was to restore the fragment to an anatomical position before definitive fixation.
Step 3: Modular Suspensory Fixation
The researchers then created a double Endobutton construct using:
- Two UltraTapes
- A 10-mm titanium ULTRABUTTON
- A 15-mm round titanium XTENDOBUTTON
- Another 15-mm XTENDOBUTTON for distal fixation
- Suture anchor augmentation
The construct was introduced, tightened and fixed to provide stabilisation of the fracture fragment.
Why Use a Double Endobutton Construct?
Suspensory fixation uses a button-and-loop system to hold a bone fragment in position.
According to the authors, the modular modification was intended to provide a more even distribution of compression across the fracture fragment.
The authors believed this could also reduce the risk of button pull-through, where the fixation button could potentially pull through the bone fragment under load.
This was the rationale for developing the modified construct.
How Long After the Injury Was Surgery Performed?
The patient underwent arthroscopic fixation 13 days after the initial injury.
The timing of surgery in an individual patient depends on factors such as:
- Injury severity
- Swelling
- Associated injuries
- Medical condition
- Surgical planning
The timing used in this case should therefore not be interpreted as a universal recommendation for all PCL avulsion fractures.
What Was the Patient’s Outcome?
The patient recovered well following the procedure.
The authors reported that he was reviewed eight weeks after surgery and had a good clinical outcome.
However, because this was a single case report, the result cannot establish that the technique will produce the same outcome in other patients.
What Were the Researchers Trying to Achieve?
The technique was designed around several objectives:
- Restore the displaced bone fragment anatomically
- Provide stable fixation
- Distribute compression across the fragment
- Reduce the risk of fixation button pull-through
- Perform the procedure arthroscopically
The authors concluded that their modification could be considered for similar cases in the future.
What Are the Potential Advantages of an Arthroscopic Approach?
Arthroscopic surgery uses small portals rather than a large incision over the back of the knee.
Potential advantages of arthroscopic approaches can include:
- Smaller surgical access points
- Direct visualisation of the knee joint
- Ability to assess associated intra-articular injuries
- Potentially less disruption of surrounding soft tissues
However, arthroscopic fixation of PCL avulsion fractures can be technically demanding because of the location of the fracture and nearby anatomical structures.
The technique described in this research should therefore be understood as a specialised surgical approach rather than a procedure that is automatically appropriate for every patient.
Is This Technique Suitable for Every PCL Avulsion Fracture?
Not necessarily.
The report describes one patient with a specific fracture pattern and does not establish selection criteria for every PCL tibial avulsion fracture.
Treatment decisions may depend on:
- Fragment size
- Degree of displacement
- Fracture configuration
- Knee stability
- Associated injuries
- Patient activity requirements
- Surgeon experience
Some PCL injuries may be managed differently depending on their characteristics.
What Are the Limitations of the Research?
Understanding the study design is important when interpreting its findings.
It Was a Single Case Report
Only one patient was treated using the described technique.
Therefore, the study cannot determine:
- How often the technique succeeds
- How it compares with other fixation methods
- Whether it provides better long-term outcomes
No Control Group
There was no comparison group treated using another fixation technique.
Short Follow-Up
The reported clinical outcome was assessed at eight weeks postoperatively. This provides information about early recovery but does not establish long-term outcomes such as:
- Long-term knee stability
- Development of post-traumatic arthritis
- Long-term implant or fixation durability
- Return to high-level sports
Further Research Is Needed
Larger patient series and comparative studies would be needed to determine how the technique performs across different fracture patterns and against established fixation methods.
What Does This Research Mean for Patients?
For patients, the research provides an example of how arthroscopic techniques can be adapted to address technically challenging PCL avulsion fractures.
The key findings are:
- The case involved a displaced PCL tibial avulsion fracture following a motorcycle accident.
- The patient was a 42-year-old man.
- The fracture fragment measured 3.1 cm × 2.6 cm × 1.5 cm.
- Arthroscopic fixation was performed 13 days after injury.
- A modified double Endobutton construct was used.
- The patient had a good clinical outcome at eight-week follow-up.
The research does not establish the technique as superior to other methods. Instead, it describes a specific modification intended to improve compression distribution and reduce the risk of fixation failure.
A 2021 case report from Singapore described a modified arthroscopic fixation technique for a displaced PCL tibial avulsion fracture. The technique used a modular double Endobutton construct designed to distribute compression across the fracture fragment and reduce the potential for button pull-through.
The technique was used in a 42-year-old man who sustained a displaced PCL tibial avulsion fracture in a motorcycle accident. He underwent arthroscopic fixation 13 days after injury and had a good clinical outcome at eight-week follow-up.
As a single case report, the research provides an example of a surgical technique rather than evidence that this approach is superior to other methods. Further research involving more patients and longer follow-up would be needed to establish its effectiveness and broader applicability.
For patients with a PCL avulsion fracture, treatment should be based on the specific fracture pattern, knee stability, associated injuries and individual functional goals.
Research Reference
Lee Zhao Jie J, Wang L. Arthroscopic modular suspensory fixation of posterior cruciate ligament tibial avulsion fracture: a novel technique. Arthroscopy and Orthopedic Sports Medicine. 2021;8(2):61-66. DOI: 10.14517/aosm20007.
The post A Less Invasive Approach to a Rare PCL Knee Fracture: What Research Shows appeared first on The Hype Magazine.
