Rupture of the anterior cruciate ligament (ACL) is a fairly common injury these days — especially among young athletes. Surgery to reconstruct the ACL has improved over the years. It is still done with one of the two graft choices you mentioned (patellar tendon or hamstring tendon) but the procedure is far less invasive now. Arthroscopic surgery with minimally invasive techniques are standard.
Surgeons have been following patients over the years to see how well the graft holds up. They are interested in improving results and long-term outcomes can help guide them in that quest. Studies are being done to address many unknowns such as:
Knowing the risk factors for rupture might help patients prevent such an event. Does it really matter which location the graft comes from (patellar tendon or hamstrings)? And finally, what about the other knee? Does having an ACL rupture on one side increase the risk of an ACL tear on the other side?
A recent study from surgeons at the North Sydney Orthopaedic and Sports Medicine Centre in Australia may help answer some of these questions. They found some answers to these questions from telephone and written surveys their patients completed. There were 755 patients who had an ACL reconstruction and participated in the study.
No one was contacted until at least 15 years had passed from the time of their first ACL surgery. They were asked all sorts of questions about knee function, further injuries to either knee, additional knee surgeries, family history of ACL injuries, activity level, and satisfaction with results of surgery.
Specific information about each patient was collected from their medical records (e.g., age, gender, leg affected, type of graft used, date of injury and date of surgery). They were able to find out all sorts of interesting information about this group of patients.
For example, rupture of the ACL on the other side was less than one per cent per year and most likely to occur between year one and year four after the primary (first) ACL surgery. Patients who had patellar tendon grafts were twice as likely to have an ACL rupture in the opposite leg compared with those patients who had the hamstring graft. The type of graft did not seem to affect the primary ACL repair — ruptures occurred equally between the patellar tendon group and the hamstring group.
ACL grafts survived intact for 97 per cent of the entire group in the first two years. But the risk of rupture increased as time went by. Rupture of the surgical graft affected 11 per cent of the group. When rupture did occur, it was most likely to happen in the first year after the primary surgery. Men and women experienced graft rupture equally.
There was one final bit of information gleaned from this study. Patients with a family history of ACL rupture had double the risk of both ACL graft rupture and rupture of the ACL on the other side. This bit of information may be of interest to your sister given your history of an ACL injury.
At least in this study, graft type (patellar tendon) and age (younger patients) were two of the main risk factors identified for further injury. Younger age is linked with higher activity level and therefore increased risk of injury. Your sister will want to take this information into consideration along with whatever counsel and guidance her surgeon offers. Identifying and minimizing all modifiable risk factors requires both surgeon and patient participation and cooperation in the process.