By Dev Mishra, M.D.
President, Sideline Sports Doc
Clinical Assistant Professor of Orthopedic Surgery, Stanford University
In today’s blog post I’d like to take a look at improved outcomes over the last 25 years from a commonly performed orthopedic sports medicine surgery: ACL reconstruction. We’ve come a long way over this time, with improvements in patient reported outcomes as well as improvements in measured stability of the knee.
Orthopedic surgeons use various objective criteria to assess the stability of the knee. In 1994 when I started my orthopedic practice I typically quoted an 80% success rate in terms of restoring excellent stability to the knee after ACL reconstruction surgery. Today, that number is about 95%.
How the patient who’s had surgery feels about his or her own knee has also improved quite a bit over this time. It’s difficult to find published patient reported outcomes from the early 90s but it’s fair to say that a large percentage of patients weren’t entirely happy with their knees after surgery. Perhaps 40% of people reported difficulties with their knees. Nowadays patient reported outcomes are generally very favorable for about 80% of knees at least two years after surgery.
Improvements In Surgical Technique And Better Understanding Of Anatomy
Orthopedic scientists didn’t have a good understanding of what the ACL was or what it did prior to the 1970s. But starting in the 1970s there was an understanding that the ACL was an important stabilizer of the knee, and some surgery was performed. Most of those surgeries are what would now be called “extra articular” surgeries, meaning that they didn’t directly repair or rebuild the ACL. Rehabilitation was exceptionally difficult and many surgeries failed.
In the 1980s there was more of an understanding that we had to re-create a new ACL, a surgery that we now call a reconstruction. Tissue was transferred from one place in the knee and used to rebuild and replace the torn ACL. This improved surgical technique resulted in a very substantial improvement in outcomes after surgery.
Further refinements took place in the 2000’s. Most of these refinements were driven by improved understandings in the anatomy of the ACL, and improvements in our ability to more precisely place the tissue graft within the knee joint. ACL fixation techniques also improved, in many cases allowing for a more rapid rehabilitation than was possible previously.
We’ve gained a much better understanding of where exactly to place the graft within the knee joint. To the non-medically trained observer these differences may not seem like much if you were to look at a drawing of the reconstruction, however they have resulted in substantial improvements in stability and patient outcome. These changes are a really big deal from the surgeon’s standpoint.
We have a much better understanding now of how to best rehabilitate a knee after ACL surgery. Rather than using arbitrary time points to determine readiness for return to sport, there is an increasing understanding of biomechanical and functional landmarks to help make this decision. This should result in lower retear rates after surgery.
Biologic augmentation of the surgery with stem cells or other bioactive agents may lead to enhancements in the quality of the new ACL. And in some instances of a partial ACL tear, there is renewed interest in performing a suture repair of the torn ACL segment and augmenting this with a stem cell treatment.
The newer biologic treatments are very exciting and have the potential to offer further improvements in outcomes. I expect that if I write this article 5 years from now the numbers that I quoted above will be substantially improved.