By Dev K. Mishra, M.D.
President, Sideline Sports Doc
Clinical Assistant Professor of Orthopedic Surgery, Stanford University
- Repairing a torn ACL with stitches rather than replacing the torn ACL with a new tissue has several theoretical advantages
- A recent clinical study unfortunately showed a 49% failure rate of ACL repair in adolescents out to about 3 years, thus making this surgery inadvisable
- Future directions include augmenting the repair with scaffolds or stems cells, which have the potential to improve the outcomes
What if it was possible to repair the torn ACL by using stitches rather than replacing it with tissue removed from another area
ACL suture repair, from Gagliardi et al
in the body? This is attractive as it would theoretically lead to an easier rehab, and avoid possible injury to the growth plates in adolescents. However, a recently published study showed a 49% failure rate at 3 years, compared to a 5% failure rate for traditional ACL reconstruction. This is an unacceptably high failure rate, and ACL repair with stitches is not advised for young athletes.
Many young athletes with ACL tears will opt for ACL surgery in order to improve stability in the knee and allow for a return to cutting and pivoting sports. The standard ACL surgery is called a “reconstruction” and involves replacing the torn ACL with tissue taken from another area in the body. ACL reconstruction surgery has evolved and is now highly successful, with success rates in the 94% to 97% range for adults.
But ACL reconstruction has some downsides. The area where the tissue is taken (typically the patellar tendon, the hamstrings, and sometimes the quadriceps tendon) can be weakened by the surgery leading to problems. Additionally, for the growing athlete the growth plates around the knee can be injured, leading to the possibility of growth related angular changes or shortening. Failure rates tend to be higher in adolescents compared to adults.
ACL Repair With Stitches
ACL repair with stitches has been attempted for decades, and previous studies have shown poor results so the procedure never caught on. The authors of the study referenced in this post had very specific criteria for possible repair, notably that the tear was essentially a detachment from the bone rather than tearing in the middle of the ligament. They performed a suture repair without augmenting the repair with stem cells or other healing enhancers.
In spite of strict criteria, meticulous technique from a highly experienced surgeon, and strict rehabilitation, the re-tear rate for the repair group was 48.8% when followed out to about 3 years. The re-tear rate in their reconstruction group was 4.7% out to 3 years. Clearly, the failure rate for the repair group is unacceptable and the authors have recommended against this type of repair.
Future Directions: ACL Repair With Scaffold And Stem Cell Augmentation
The addition of a scaffold with stem cells surrounding the ACL repair is very exciting and currently undergoing clinical trials. The very early results are promising but caution is necessary since the patients are not far enough out from surgery to reach meaningful conclusions about success.
ACL repair techniques are improving as we gain additional knowledge about the best candidates for surgery, surgical technique is evolving, and as we gain additional insight about possible benefits of augmenting the repair with healing enhancers. I applaud the authors of the study for taking on an ambitious and well-intentioned study. I expect that we’ll see more augmented ACL repairs down the line with modifications to this technique.