If you have a torn anterior cruciate ligament (ACL), you may hear two surgical terms: ACL repair and ACL reconstruction. Although both procedures aim to restore stability to the knee, they are not the same operation.
ACL repair attempts to preserve and reattach the injured ligament. ACL reconstruction, on the other hand, replaces the damaged ACL with a tendon graft. Reconstruction remains the standard surgical treatment when an ACL tear requires surgery, while repair may be appropriate only for carefully selected tear patterns.
ACL Repair vs ACL Reconstruction at a Glance
| Feature | ACL Repair | ACL Reconstruction |
|---|---|---|
| What happens to the ACL? | The torn ACL tissue is reattached and supported so it can heal. | The damaged ACL is replaced with a tendon graft. |
| Uses the patient's original ACL? | Yes, when the remaining tissue is suitable. | No. The damaged ligament is replaced with a graft. |
| Who may be considered? | Selected patients, particularly with certain acute proximal tears and good-quality ligament tissue. | Patients with ACL tears for whom surgical stabilization is indicated. |
| Current role | Limited and selective. | Established standard surgical approach. |
What Is ACL Reconstruction?
ACL reconstruction removes or bypasses the damaged ligament and creates a new ligament using a tendon graft. The graft may be taken from another part of your own body, such as the patellar tendon, hamstring tendon, or quadriceps tendon. This is known as an autograft.
In some circumstances, tissue from a donor may be used instead, although graft selection depends on factors such as age, activity level, injury characteristics, and surgeon assessment.
The graft is positioned through tunnels in the thighbone and shinbone to reproduce the function of the original ACL. Over time, the graft undergoes biological changes as it incorporates into the knee.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
What Is ACL Repair?
ACL repair is different because the surgeon attempts to preserve the patient's own injured ligament rather than replace it with a graft.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
During repair, the torn ligament may be repositioned and secured using sutures, anchors, or other forms of support. Some techniques may also use additional reinforcement to help protect the repaired ligament while it heals.
The idea behind repair is to preserve the patient's native ACL tissue. However, a torn ACL is not automatically suitable for repair. The location of the tear and the quality of the remaining ligament tissue are particularly important.
Why Isn't Every Torn ACL Repaired?
The ACL can tear in different locations and patterns. A ligament that has pulled away close to its attachment on the thighbone may have more repairable tissue than a ligament that has torn through its middle portion or has become severely damaged.
For this reason, simply knowing that an ACL is torn is not enough to determine whether repair is possible. Repair is generally considered only when the remaining ligament tissue is of suitable quality and the tear pattern provides a reasonable opportunity for the ligament to be reattached and heal.
Recent research has renewed interest in ACL repair, particularly for selected acute proximal tears. However, the evidence remains limited, and longer-term comparative data are still developing.
When Is ACL Reconstruction Usually Preferred?
When an ACL tear requires surgical treatment, reconstruction is generally preferred over primary repair. Current orthopedic guidance recommends reconstruction because comparative evidence has shown a lower risk of revision surgery compared with repair.
Reconstruction may be considered when:
- The ACL is completely or functionally torn and the knee is unstable.
- The person wants to return to sports involving pivoting, cutting, or rapid changes in direction.
- The tear pattern is not suitable for primary repair.
- The remaining ACL tissue is too damaged or poor in quality to provide reliable healing.
- There are associated injuries that require surgical management.
- Nonsurgical treatment has not provided adequate functional stability.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
When Might ACL Repair Be Considered?
ACL repair has a much narrower role. It may be discussed when the injury is recent, the tear is located close to the ligament's attachment, and enough healthy tissue remains to allow the ligament to be reattached.
The decision may also depend on the patient's age, activity level, other knee injuries, and the specific surgical technique being considered.
It is important to understand that being technically eligible for repair does not automatically mean that repair is the preferred treatment. The potential benefits need to be weighed against the possibility of the repair failing and requiring another operation.
Does ACL Repair Have Advantages?
One potential advantage of repair is that it preserves the patient's own ACL tissue rather than replacing it with a graft. Because no graft needs to be harvested, repair may also avoid some of the issues associated with graft harvesting.
There is also scientific interest in whether preserving the native ligament could retain some of its sensory and biological functions. However, these potential advantages should not be interpreted as proof that repair is better than reconstruction.
Research comparing the two approaches has produced mixed findings. Some studies report similar short-term functional outcomes, while comparative evidence has found higher rates of clinical failure and revision after primary repair overall. Long-term evidence is still limited.
What About Recovery?
Both procedures require structured rehabilitation, and neither should be viewed as a quick fix for knee instability. After ACL reconstruction, rehabilitation focuses on restoring knee movement, reducing swelling, rebuilding strength, improving balance and neuromuscular control, and gradually returning to normal activities and sports.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
ACL repair also requires rehabilitation to protect the healing ligament while gradually restoring movement and strength. The exact rehabilitation protocol can differ according to the repair technique, associated injuries, and the surgeon's assessment. Return to sport should be based on functional recovery rather than simply the number of weeks since surgery.
The Bottom Line
ACL repair and ACL reconstruction have the same broad goal—restoring stability to an unstable knee—but they achieve it in different ways. Repair preserves and reattaches the injured ACL, while reconstruction replaces the damaged ligament with a tendon graft.
Reconstruction remains the standard surgical approach when an ACL tear requires surgery because it has more established evidence and a lower risk of revision than primary repair. Repair may be considered in carefully selected patients, particularly when the tear is recent, located near the ligament's attachment, and the remaining tissue is suitable for healing.
The most appropriate choice depends on the tear pattern, knee stability, associated injuries, activity goals, and the quality of the remaining ligament. A detailed orthopedic assessment is therefore essential before deciding between ACL repair and reconstruction.
