When a ligament is injured, it does not always tear in the middle. In some injuries, the ligament remains attached to a small piece of bone, but this piece of bone is pulled away from its normal attachment. This is called a ligament avulsion injury.

In selected patients, the detached bone fragment can be returned to its normal position and secured using arthroscopic ligament avulsion fixation. This allows the original ligament attachment to heal without necessarily replacing the ligament with a graft.

What is a ligament avulsion injury?

A ligament connects one bone to another and helps keep a joint stable. Sometimes a strong force causes the ligament to pull away from its attachment on the bone, taking a small piece of bone with it.

This is different from a typical ligament tear, where the ligament itself is disrupted.

Avulsion injuries can occur in several joints. Around the knee, important examples include:

• ACL tibial avulsion, also called a tibial spine or tibial eminence fracture

• PCL tibial avulsion, in which the PCL pulls away from its attachment on the back of the tibia

• Selected avulsion injuries involving other knee ligaments or their bony attachments

The exact treatment depends on the location, size and displacement of the bone fragment, the stability of the joint and the overall condition of the ligament.

When is fixation needed?

Small, minimally displaced avulsion injuries may sometimes be treated without surgery, particularly when the knee remains stable and the fragment is unlikely to interfere with movement.

Surgery may be recommended when the avulsed fragment is significantly displaced, the ligament attachment has moved out of its normal position, the knee is unstable, or the fragment interferes with normal joint movement.

The decision is made after assessing the patient's symptoms, physical examination and imaging.

What is arthroscopic ligament avulsion fixation?

Arthroscopic ligament avulsion fixation is a minimally invasive procedure in which the surgeon uses a small camera called an arthroscope to see inside the joint.

The displaced bone fragment is carefully returned to its original position and secured so that it can heal back to the surrounding bone.

Depending on the type and location of the injury, different fixation techniques may be used, including:

• Sutures or suture-based fixation

• Small fixation devices

• Screws in selected avulsion fractures

• Other fixation methods appropriate for the size and location of the bone fragment

The fixation method is selected according to the patient's anatomy and the type of avulsion injury.

What are the benefits of avulsion fixation?

When an avulsion injury is suitable for fixation, restoring the original ligament attachment has several potential advantages.

Preservation of the patient's own ligament

Unlike ligament reconstruction, fixation aims to preserve the original ligament and its natural attachment.

No graft is usually required

Because the original ligament is being repaired back to its attachment, a separate tendon graft is generally not required for the avulsed ligament itself.

Restoration of the normal anatomy

The objective is to return the ligament-bone attachment to its original position and allow it to heal there.

Minimally invasive surgery

Arthroscopic fixation is performed through small incisions and allows the surgeon to directly visualize the joint and the injury.

Potentially simpler rehabilitation than reconstruction

Because a new ligament graft does not need to mature and incorporate, rehabilitation may differ from that following ligament reconstruction. However, the exact rehabilitation programme depends on the injury, fixation method and stability of the repair.

Is avulsion fixation the same as ligament reconstruction?

No. They are different procedures.

In ligament reconstruction, the damaged ligament is replaced or reconstructed using a tendon graft.

In ligament avulsion fixation, the original ligament remains attached to a piece of bone that has been pulled away from its normal position. The aim is to return this bone fragment to its original location and secure it so that the ligament attachment can heal.

Therefore, when the original ligament and avulsed bone fragment are suitable for fixation, reconstruction may not be necessary.

However, not every ligament injury is suitable for fixation. A ligament that has been torn in its substance, has poor tissue quality or cannot be restored to its normal attachment may require reconstruction instead.

How soon should surgery be performed?

The timing depends on the type of avulsion injury.

Some injuries can be treated after the initial swelling and stiffness have settled, while others may require earlier intervention. The presence of a displaced fragment, restricted knee movement or associated injuries may influence the timing.

The goal is to achieve an accurate reduction while avoiding unnecessary delay.

Your orthopaedic surgeon will determine the appropriate timing based on the injury pattern and condition of the knee.

What happens after surgery?

After fixation, the knee is protected while the repaired ligament-bone attachment heals.

The rehabilitation programme may include:

• Pain and swelling control

• Early exercises to prevent excessive stiffness

• Gradual restoration of knee movement

• Progressive muscle strengthening

• Protected or partial weight-bearing for a period when required

• Gradual return to normal walking

• Progressive functional and sport-specific rehabilitation

The exact restrictions depend on the type of avulsion, quality of fixation and associated injuries.

Following the rehabilitation programme is an important part of achieving a good result.

When can I walk after surgery?

Walking after surgery depends on the type of avulsion and the stability of the fixation.

Some patients are allowed to put weight on the leg relatively early, while others may need a period of protected or partial weight-bearing.

Your surgeon and physiotherapist will provide a specific weight-bearing plan for your injury.

When can I return to work?

The timing depends on your occupation.

Patients with desk-based work may return earlier once pain and mobility are adequately controlled. Jobs requiring prolonged standing, walking, climbing or physical activity generally require more time.

Your return-to-work plan will be individualised according to your recovery.

When can I return to sports?

Returning to sports requires more than simply being able to walk without pain.

Before returning to demanding sports, the knee should have adequate:

• Range of motion

• Muscle strength

• Stability

• Balance and coordination

• Functional performance

The timing varies considerably between patients and depends on the type of avulsion, healing on follow-up assessment and the demands of the sport.

A gradual, rehabilitation-based return to sport is safer than returning as soon as the knee feels comfortable.

What are the risks of arthroscopic avulsion fixation?

Arthroscopic ligament avulsion fixation is generally a well-established procedure when appropriately indicated. As with any surgery, complications can occur, although serious complications are uncommon.

Possible complications include:

• Infection

• Bleeding or blood clot formation

• Knee stiffness

• Persistent pain or swelling

• Failure of the bone fragment to heal properly

• Loss of reduction or fixation failure

• Persistent ligament instability

• Need for further surgery

• Injury to surrounding structures

Some patients may develop stiffness after fixation, particularly when knee movement is restricted for an extended period. Rehabilitation therefore aims to balance protection of the healing fixation with restoration of knee movement.

What happens if the avulsed fragment does not heal properly?

If the bone fragment does not heal in an appropriate position, the ligament may remain loose or the fragment may interfere with knee movement.

Persistent instability or significant movement restriction may require further assessment and, in selected cases, additional surgery.

The likelihood of this depends on the injury pattern, displacement, bone quality, fixation stability and rehabilitation.

Will I need ligament reconstruction after avulsion fixation?

Not necessarily.

The purpose of fixation is to restore the original ligament attachment and allow it to heal. If the ligament heals appropriately and the knee becomes stable, reconstruction may not be necessary.

However, if the ligament remains insufficient, the fragment fails to heal appropriately, or significant instability persists, further treatment—including ligament reconstruction in selected cases—may be considered.

Is arthroscopic avulsion fixation better than ligament reconstruction?

Neither procedure is universally better. They are used for different types of injuries.

When a ligament has been avulsed with a suitable bone fragment, restoring the original attachment may be preferable because it preserves the patient's own ligament.

When the ligament is torn in its substance or cannot be reliably restored to its normal attachment, reconstruction may be more appropriate.

The choice depends on the individual injury rather than simply on whether arthroscopic fixation or reconstruction is technically possible.

Frequently Asked Questions

What is a ligament avulsion?

A ligament avulsion occurs when a ligament pulls away from its bony attachment, sometimes taking a small piece of bone with it.

Can a ligament avulsion heal without surgery?

Some minimally displaced avulsion injuries can heal with non-surgical treatment. Surgery is more often considered when the fragment is significantly displaced, the knee is unstable or the fragment interferes with joint movement.

Does avulsion fixation use a tendon graft?

Usually, no. The aim is to preserve the original ligament and restore its attachment to the bone. A tendon graft may be needed later only if the original ligament cannot provide adequate stability.

Is arthroscopic avulsion fixation a major operation?

It is performed through small arthroscopic incisions, but it is still a surgical procedure that requires appropriate fixation and rehabilitation. The complexity depends on the location and severity of the injury.

How long does it take to recover?

Recovery varies according to the ligament involved, the fracture pattern, fixation method and rehabilitation programme. Returning to unrestricted sports generally takes considerably longer than returning to normal daily activities.

Can I bend my knee after surgery?

Knee movement is usually introduced gradually, but the amount and timing depend on the injury and fixation. Your surgeon will provide specific instructions regarding the safe range of movement.

Can I return to sports after avulsion fixation?

Many appropriately treated patients can return to sports. However, return should be gradual and should follow restoration of adequate strength, movement, stability and functional performance.

Will I need physiotherapy?

Yes. Physiotherapy is an important part of recovery. It helps restore knee movement, muscle strength, coordination and function while protecting the healing ligament attachment.