Anterior cruciate ligament (ACL) injuries are not what they used to be: A recipe for pain and possibly permanent disability. Modern medical technique and technology allows serious athletes, weekend warriors and everyone else to return from an ACL tear or rupture potentially as good as new.
Orthopedic surgeons can make this happen by performing ACL reconstructions. An ACL reconstruction is a procedure that creates an environment within the knee that encourages growth of new connective tissue. How? One of the most important aspects of an ACL reconstruction is the tissue graft.
What Is an ACL Graft?
ACL sprains (“sprain” is a term for an injury to a ligament, one of the tough pieces of tissue that connects bones) are some of the most common knee injuries, and severe ACL sprains—often called ACL tears or ACL ruptures—very often need ACL reconstruction surgery. ACL sprains are graded in severity from 1 to 3. Most ACL sprains are either mild (grade 1) or fully torn (grade 3); there’s not much of a middle ground when it comes to ACL injuries.
A tissue graft is the main component of an ACL reconstruction surgery. The tissue graft is usually placed in the knee arthroscopically, with multiple small incisions, small tools and a flexible camera, called an arthroscope, that allows the surgeon to see what he or she is doing. The graft acts as a scaffold for the body to build new connective tissue.
Autograft vs. Allograft in ACL Reconstruction
Surgeons and patients have two main choices for their grafts: autograft and allograft. An autograft is tissue taken from a patient’s own body. It is often but not always a tendon—tissue that connects muscle to bone. The most common harvesting sites for an autograft include:
- Patellar tendon, which connects the kneecap (patella) to the shin bone (tibia); note that the patellar tendon is actually a ligament
- One of the tendons that connects the hamstring to the tibia (usually either the semitendinosus tendon or the gracilis tendon)
- Quadriceps tendon, which connects the quadriceps muscle to the kneecap
The other common choice for an ACL graft is known as an allograft. An allograft is harvested not from the patient but from a donor cadaver. Some allografts are harvested from the same sites as autografts, and some may be from donors’ Achilles tendons or a calf tendon.
Making the Choice: Autograft or Allograft
The choice between autograft and allograft is one that must be made by the patient and surgeon together. The surgeon will lay out the risks and benefits of each and give his or her opinion, and the patient should be allowed input as well.
Both autografts and allografts can be very effective in repairing ACL tears. A 2016 meta-analysis using data from more than 1,600 patients suggests that autograft and one type of allograft (nonirradiated) have no significant difference in various pain and function measurements or the rate of failure.
Some data suggest that autografts may be the better choice for younger, active people with ACL tears. A 2015 systematic review published in the American Orthopedic Society for Sports Medicine’s journal found that failure rates were higher when using an allograft in patients younger than 25 years. The risk of failure was more than double in allografts (25 percent) compared to autograft (9.6 percent).
Despite this caveat, both allografts and autografts are safe and effective. Each carries certain benefits and risks that must be compared and weighed.
- No extensive preparation or preservation necessary
- Healing is often faster and with fewer complications
- Requires removing tissue from another part of the body
Sometimes associated with increased knee pain
- No removal of other tissue necessary
- Slower healing
- Small risk of disease transfer
- Preservation process can weaken the tissue in some cases
Ultimately it is up to the surgeon and the patient to decide which is the best graft source to use in an ACL reconstruction. I always lay out the options with my patients and listen carefully to their thoughts, as well as provide my own opinions.
Each patient’s surgery is unique, and my recommendations change with each patient depending on his or her age, activity levels, the severity of the injury and many other factors. What remains the same from patient to patient and case to case, however, is putting the patient and their needs first.
If you have experienced an ACL sprain or tear, request an appointment with me or another of Summit Medical Group Orthopedics’ sports medicine experts. We’ll clearly communicate your treatment options and help you choose the best course of care for you.