Graft choice has been shown to impact surgical outcomes. Two types of grafts exist: autografts, which are harvested from the patient’s leg, and allografts, which are typically harvested from cadavers.
Both methods have their pros and cons. Allografts pose a risk of infection due to the foreign origins of the tissue. The sterilization process can reduce the graft’s tensile strength, leading to a higher risk of rupture. However, allografts eliminate the risks of harvest morbidity, and this type of graft may be recommended for less active patients who are overall less likely to experience graft rupture.
Autografts do not require sterilization and have lower failures and rejection rates, but unlike allografts they run the risk of harvest morbidity, or weakening the area from which the graft originates. Autografts are usually taken from the patient’s patellar tendon or hamstring tendons.
Patellar tendon autografts achieve the lowest re-tear rate with 90-95% patients reporting successful outcomes. These numbers can be attributed to the historical precedent of this type of surgery: patellar tendon autografts have been used by surgeons since the 1980s. More importantly, the strength and rapid healing rate of the patellar tendon prevents risk of early failure. Yet, patients who have received this type of graft also report more pain and larger scarring than patients who have received other types of autografts. ACL reconstruction with patellar tendon autograft is especially good for double-jointed patients. Petite individuals with narrow patellar tendons, or workers that must frequently put pressure on their knees, would not be as well-suited for this type of graft.
Hamstring autografts are less painful and require a smaller incision, yet have a higher re-tear rate. Hamstring autografts are also a good option for younger patients who are still growing because hamstring grafts are less likely to lead to premature closure of their growth plates.
Both autografts and allografts can achieve good outcomes. Though patellar tendon autografts are typically the ‘gold standard’, the success of the particular graft ultimately depends on the patient. Every knee is unique and every patient’s requirements and desires are different, making it the surgeon’s job to ensure care is personalized for each patient.