A tear of the anterior cruciate ligament (ACL) is one of the most disabling knee injuries that afflicts athletes and athletic people. Most patients undergo surgery to restore knee stability and function in order to allow return to sports and exercise. In fact, it has been estimated that approximately 200,000 ACL reconstruction surgeries are performed each year.
Graft options for ACL reconstruction
In an ACL reconstruction, the surgeon creates a new ligament using tissue from the patient (autograft) or from a donor (allograft). The most popular autograft options for ACL reconstructions are the central third of the patellar tendon (the tendon below the kneecap) and the hamstring tendons. Allograft options include tibialis anterior, tibialis posterior, hamstring, Achilles and patellar tendons.
A new study presented at the Annual Meeting of the American Orthopaedic Society of Sports Medicine (AOSSM) suggests that the type of graft used for the reconstruction might play a large role in the life span of these operations.
Life span of autograft vs. allograft ACL reconstructions
Researchers at Tripler Army Medical Center in Honolulu, Hawaii performed a randomized prospective study among patients 18 years of age or older with ACL-deficient knees who had failed nonoperative treatment. 95 percent of the patients were active duty in the military. Each patient was randomized to receive either a tibialis posterior allograft or hamstring autograft. Other than the graft itself, all patients underwent the same surgical procedure, graft fixation, and postoperative rehabilitation protocol with physical therapy. The patients were contacted by phone and email at a minimum follow up of 120 months (10 years).
Even after 10 years or more since the initial ACL surgeries were performed, over 80% of all the patients had maintained knee stability following ACL reconstruction. However, 12 of the patients (24.5%) receiving allografts had graft failures requiring revision, while only 4 of the patients (8.5%) receiving autografts had failed.
“Our study results, highlight that in a young athletic population, allografts (tissue harvested from a donor) fail more frequently than using autografts (tissue harvested from the patient),” noted the study’s lead author Craig R. Bottoni, MD. “After following the patients for 10 years, more than 80 percent of all grafts were intact and had maintained stability. However, those patients who had an allograft, failed at a rate more than three times higher than those reconstructed with an autograft.”
Pros and cons of autografts and allografts
Autografts have largely been the preferred choice among sports medicine surgeons for younger, more athletic individuals undergoing ACL reconstructions. The main drawbacks are donor site pain and morbidity related to harvesting tissue from the patient’s knee.
On the other hand, allografts initially were used more in revision ACL reconstructions and primary surgeries involving older, less athletic patients. Their use does appear to be increasing in the United States. A lack of donor site morbidity makes them somewhat attractive options. Potential drawbacks to allograft use include slower incorporation into the knee, weaker grafts, theoretical risks of disease transmission and cost.
Also read and listen to the discussion from The Dr. David Geier Show:
The most important question to ask before ACL surgery?
Episode 114: How do allografts compare to autografts for ACL surgery? (starts at 5:27)
Should a younger, more active patient choose to use his or her own tissue?
In the conclusion of their study, the authors summarized their findings. “In a young, active population, an ACL reconstruction using either an autograft hamstring or tibialis allograft provided stability and good to excellent subjective function in the vast majority of patients out past 10 years. However, the knees reconstructed with an autograft hamstring demonstrated statistically significant graft survivability when compared to the knees reconstructed with a tibialis posterior allograft.”
There is still much we need to learn to determine the best graft option for every patient undergoing ACL reconstruction. Despite the potential for less pain in the weeks after the surgery if the patient chooses an allograft, that choice carries with it an apparent higher risk of graft failure in the coming years. Younger, active patients wishing to return to physically demanding sports and activities at least need to consider this risk and discuss it with the surgeon.
If you perform ACL surgeries, or rehab patients who have undergone them, what advice or experience with graft choices would you share with others? If you have had an ACL surgery, how did you decide on a graft? Please share your thoughts!
Shaha J, Smith E, Raybin S, Tokish J, Rowles D, Bottoni C. Autograft versus Allograft ACL Reconstructions: A Prospective, Randomized Clinical Study with Minimum 10 Year Follow-up. Presented at the 2014 Annual Meeting of the American Orthopaedic Society of Sports Medicine.