By C. David Geier Jr. MD
Should an orthopedic surgeon performing ACL reconstruction on a competitive athlete use a patellar tendon or hamstring graft?
It is an important question that has been debated for years. Numerous studies, including many randomized controlled trials, have aimed to analyze differences in patient outcomes after ACL reconstructions using patellar tendon and hamstring autografts.
Now a new study in the American Journal of Sports Medicine looks at one specific component of a patient’s outcome after ACL reconstruction: the risk for future revision surgery.
Though surgeons overwhelmingly used hamstring autografts, researchers found a significantly lower risk of revision surgery in patients who received patellar tendon autografts.
In addition, type of activity that the patient was performing at the time of injury mattered.
“Should a soccer or team handball player with a ruptured ACL receive a patellar tendon autograft over a hamstring autograft? In view of the findings in the present study, we believe that patellar tendon autografts may be suitable especially for patients returning to pivoting activities with high demands for stability,” authors concluded.
Fewer Patellar Grafts, Fewer Revisions
Tone Gifstad, MD, PhD, orthopedic surgeon at Trondheim University Hospital in Norway, and colleagues collected data from 45,402 patients who underwent ACL reconstruction entered into Norwegian, Danish, and Swedish national knee registries between 2004 and 2011.
Data included graft selection, patient age, sex, activity at the time of injury, side of injury, concurrent meniscal or cartilage injury, and potential date of revision. The average follow-up time of study patients was 3 years.
Autografts were almost exclusively used — only 1.3% of the ACL reconstructions involved allografts or other sources.
Scandinavian surgeons overwhelmingly preferred and used hamstring autografts. A total of 84.1% of the patients in the study had hamstring grafts, compared with 14.6% with patella tendon autografts.
In contrast, in the U.S., there seemed to be more balance between use of patella tendon autografts, hamstring autografts, and allografts.
Overall, the authors observed a fairly low rate of revision surgery. Very few patients required revision ACL reconstruction in the first year. Older patients generally had better outcomes, with a lower risk of revision than did younger patients. The risk of revision decreased with each increasing 5-year age category.
A total of 156 patients in the patellar tendon group had revisions, compared with 1,042 patients in the hamstring group.
Using survival analysis, the authors determined that 5 years after primary ACL reconstruction, the expected proportion of revisions was 2.8% for the patellar tendon patients compared with 4.2% for the hamstring patients.
Normally one would think that a predominance of one graft would influence the results. If so, one would assume that the graft used more would have lower rates of revisions. In fact, despite being used in only one of every seven primary ACL reconstructions, patellar tendon grafts needed far fewer revisions.
The significant difference observed between the outcomes of patellar tendon and hamstring autografts differed from studies showing essentially equal outcomes based on different subjective scores, functional scores, or return to play.
This study just focused on risk for revision. While the risk appeared to be low for patients receiving either graft, it was lower for the patellar tendon graft.
Sport and Age Matter
Another interesting finding of the study centered on the activity of the patient at the time of injury. The authors found that the reduction in revision risk for patellar tendon grafts was more pronounced in athletes injured when playing soccer or handball or performing alpine activities.
Patellar tendon autografts have historically been popular choices for athletes in competitive sports like football. This study suggests that choice of patellar tendon versus hamstring graft should include the type and level of sport played.
The study reinforces findings by several other recent studies that young age of the patient at the time of ACL reconstruction presents a higher risk for graft rupture and need for revision.
As a result, it might be important to discuss age as a risk factor for possible graft injury and need for revision surgery with high school and college athletes.
One limitation: the study was registry-based, as opposed to a randomized, controlled trial.
But given the low rate of revisions after ACL reconstruction, authors wrote that such a large patient registry might be better able to show differences between grafts. They noted that the 45,402 ACL reconstructions and 1,198 revisions make it the largest data set examining risk of revision in the scientific literature.
The debate regarding the optimal graft for patients undergoing ACL reconstruction will continue. This study presents valuable information that orthopedic surgeons can use to counsel patients and make graft choices.