ACL repair with internal brace is changing how surgeons treat knee ligament injuries, with promising outcomes and faster return to sport.
For decades, reconstruction (replacing the torn ligament with a graft) was the gold standard for anterior cruciate ligament (ACL) injuries. But a growing body of research now supports a different approach:
The information presented in this article is drawn from a comprehensive systematic review titled Suture-augmented primary anterior cruciate ligament repair with internal brace shows acceptable re-rupture rates, favourable outcomes and high return-to-sport rates: A systematic review, published in the Journal of Experimental Orthopaedics and led by Pr. Etienne Cavaignac and his international research team.
How does ACL repair with internal brace work?
Traditional ACL surgery involves removing the damaged ligament entirely and replacing it with a tendon graft, typically harvested from the patient’s hamstring or patellar tendon.
This tape acts as a scaffold during healing. It protects the repaired ligament from excessive strain in the early post-operative weeks, reduces the risk of elongation (gradual stretching that would loosen the knee), and allows earlier mobilisation. Preserving the original ligament also means preserving its nerve endings, which play a role in proprioception (the body’s ability to sense joint position). In practical terms, patients may regain a more natural feeling in their knee compared to a reconstructed one.
Not every torn ACL is suitable for repair. The technique works best for proximal tears (those occurring near the top of the ligament, close to the femur) in patients with good tissue quality. The ACL repair with internal brace protocol therefore involves careful patient selection, typically favouring individuals operated on within a few weeks of injury, with a tear pattern amenable to direct suture.
Re-rupture rates and safety of internal brace for ACL repair
One of the key concerns with any ACL surgery is the risk of the ligament failing again. Historically, ACL repair was abandoned in the 1980s precisely because early techniques showed unacceptable re-rupture rates. So what does the modern evidence say?
Across the 13 studies reviewed, the overall re-rupture rate for ACL repair was 10.6%, with individual studies reporting rates between 4.8% and 26.1%. These figures sit within the range commonly observed after ACL reconstruction, the current standard of care.
| 10.6% | 7.4%–14.2% | |
| 1.2 years | 1.0–1.3 years | |
| 19.8 years | 14.8–24.8 years | |
| 3.2% | 0.9%–6.5% |
Several observations stand out. Re-ruptures tended to occur around one year after surgery, and the average age of patients who experienced failure was under 20, which is consistent with the well-documented higher re-injury risk among younger, more active individuals regardless of surgical technique.
The rate of reoperations unrelated to re-rupture (mainly removal of hardware such as anchors) was low at 3.2%. Only one study reported non-surgical complications, including a small number of cases of symptomatic hardware and one case of anterior knee pain. Overall, the review concluded that internal bracing does not introduce a significant burden of complications.
Return to sport after ACL repair with internal brace
For athletes and active individuals, the timeline for returning to sport is often as important as the surgical outcome itself. The ACL repair with internal brace protocol showed encouraging results on this front.
The mean time to return to sport was 9.5 months, with some studies reporting return as early as 6 months post-operatively. Among the studies that tracked return-to-sport rates, over 76% of patients successfully returned to sporting activities, with the highest rate reaching 87%.
Return to pre-injury level
Going back to sport is one thing; performing at the same level as before the injury is another. Two studies specifically measured this outcome. Heusdens et al. (2021) and Ferreira et al. (2022) reported that 67% of patients returned to their pre-injury activity level, with individual rates ranging from 66.7% to 74.7%. The mean post-operative score on the Tegner activity scale (a widely used measure of physical activity level, graded from 0 to 10) was 5.9, which corresponds to recreational sports such as jogging, cycling or swimming.
These findings are reinforced by comparative data. Vermeijden et al. (2020) studied patients who had undergone repair on one knee and reconstruction on the other. They found no significant differences in functional scores, but patients reported less pain, earlier recovery of range of motion and a preference for the repaired knee. Ferreira et al. (2022) similarly observed faster hamstring strength recovery and higher forgotten joint scores (FJS-12, a questionnaire that measures how much a patient “forgets” about their operated knee during daily life) in the repair group, with a greater proportion of patients reaching the patient-acceptable symptom state.
Patient outcomes and functional recovery
Beyond re-rupture rates and return-to-sport timelines, the review examined how patients felt and functioned after surgery using validated questionnaires.
- IKDC score (a global measure of knee function): mean of 86.9 out of 100 post-operatively, up from 49.5 before surgery
- KOOS total score (covering pain, symptoms, daily activities, sport and quality of life): mean of 85.0, up from 49.5
- Lysholm score (assessing knee stability and function): mean of 91.3
- VAS pain score (visual scale from 0 to 10): mean of 1.1, down from 2.9 pre-operatively
- KT-1000 side-to-side laxity (an objective measure of knee stability): mean difference of only 0.9 mm, a value generally considered normal
Conclusion & Findings
If you are interested in the latest advances in knee surgery, we invite you to explore the other scientific studies by Pr. Cavaignac, which cover a wide range of topics in orthopaedic surgery and sports medicine.
For patients seeking expert care in ACL injuries and knee ligament surgery, Pr. Etienne Cavaignac, based at the Toulouse University Hospital (CHU de Toulouse), combines clinical excellence with a commitment to advancing surgical knowledge through rigorous research.