Anterior Cruciate Ligament (ACL) Repair

Preserving the native ligament where anatomically suitable

Anterior Cruciate Ligament (ACL) Repair

About ACL Injury

An anterior cruciate ligament (ACL) injury can cause the knee to feel unstable or “give way,” particularly during pivoting, twisting, or sporting activities. Ongoing instability may also place the meniscus and joint cartilage at risk of further injury over time.

While ACL reconstruction remains the standard treatment for most ACL ruptures, a small subset of patients may be suitable for ACL repair. This technique aims to preserve and reattach the patient’s own ACL tissue when the tear pattern and tissue quality allow.

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What is ACL repair?

ACL repair involves reattaching the torn ligament back to its femoral attachment rather than replacing it with a graft.

The procedure uses strong sutures to re-position the ligament, supported by a synthetic tape (“internal brace”) that protects the repair while healing occurs. This internal brace acts as a safety belt during early rehabilitation.

Because no graft is harvested, the hamstrings, quadriceps, or patellar tendon are not disturbed. When appropriate, this can allow faster early recovery of motion and strength.

Who is suitable for ACL repair?

ACL repair is only effective for specific tear patterns and is not appropriate for most ACL injuries.

Repair may be considered when:

  • The tear is proximal (near the femoral attachment)

  • The remaining ACL tissue is of good quality

  • Surgery is performed relatively soon after injury (generally within 3 months)

Suitability is confirmed during arthroscopic assessment at the time of surgery.

If the tear pattern is not suitable for repair, ACL reconstruction is performed during the same operation to avoid the need for a second procedure.

How ACL repair surgery is performed

ACL repair is performed using keyhole (arthroscopic) surgery.

  • The knee is examined to:

    • Confirm the ACL tear pattern

    • Assess ligament tissue quality

    • Identify any associated injuries (such as meniscal or cartilage damage)

    Associated injuries are treated during the same procedure.

  • Small bone tunnels are created in the femur and tibia to allow passage of the protective synthetic tape.

  • Strong sutures are passed through the torn ACL fibres and secured to a small button on the outer femur, re-positioning the ligament back to its attachment site.

  • The synthetic tape is tensioned and secured in the tibia, protecting the repair during early healing and rehabilitation.

Recovery and follow-up

Rehabilitation after ACL repair is structured but criteria-based, with progression guided by swelling, movement, strength, and control rather than fixed timelines.

Typical follow-up schedule

    • Wound check and dressing removal

    • Suture removal

    • Assessment of early motion

    • Review of knee extension and flexion

    • Most patients achieve full straightening and greater than 90° of flexion

    • Completion of structured rehabilitation

    • Referral for return-to-sport testing

    • Clearance for sport only after testing confirms adequate strength, control, and knee stability

Desk-based work typically requires 3–4 weeks off.

Benefits of ACL repair (when appropriate)

Potential advantages include:

  • Preservation of native ACL tissue

  • No graft harvest required

  • Smaller bone tunnels

  • Faster early recovery of movement

  • A more natural early feel to the knee

These benefits apply only when repair criteria are met. Reconstruction remains the most reliable option for the majority of ACL injuries.

Risks of ACL repair

General surgical risks include:

  • Infection: uncommon; usually managed with antibiotics

  • Blood clots (DVT/PE): rare but possible

  • Bleeding or bruising: usually temporary

Specific risks include:

  • Repair re-rupture: approximately 10%, slightly higher than reconstruction

  • Knee stiffness: usually improves with physiotherapy

  • Nerve irritation: small areas of numbness near incisions may occur and are often temporary

  • Long-term osteoarthritis: relates to the original injury rather than the repair technique

If a repair fails, ACL reconstruction can be performed later with outcomes similar to primary reconstruction.

Key points to remember

  • ACL repair is only suitable for specific tear patterns

  • Reconstruction remains the standard treatment for most ACL injuries

  • Repair preserves native tissue when anatomically appropriate

  • Rehabilitation and movement quality are critical to success

  • Return to sport is guided by objective testing, not the calendar

Frequently asked questions

  • Suitability is confirmed during arthroscopy. If repair is not appropriate, ACL reconstruction is performed during the same operation.

  • Yes. Meniscal preservation is important for long-term knee health. Repairable meniscal tears are treated during the same surgery. Meniscal repair may slow early rehabilitation but does not change long-term outcomes.

    • Walking with crutches begins on the day of surgery

    • Crutches are usually required for 1–2 weeks

    • Weight-bearing may be restricted for up to 6 weeks if a meniscal repair is performed

  • Driving is usually possible once you can safely perform an emergency stop and are off strong pain medication.

    As a guide:

    • Right knee: around 4–6 weeks

    • Left knee (automatic): around 2–3 weeks

    Always check with your surgeon and insurer.

    • Wounds should remain dry for 2 weeks

    • Pool-based rehabilitation usually begins after 4 weeks once wounds are fully healed

  • Return to competitive sport typically occurs no earlier than 6 months, and only after:

    • Strength and movement control have returned

    • Sport-specific testing is passed

    • The knee is clinically and functionally stable

 

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