Graft Choice in ACL Surgery
Abstract & Commentary
Synopsis: Although both grafts yielded acceptable results in a large literature meta-analysis, patellar tendon grafts tended to result in slightly more stable knees with a lower failure rate but at the expense of higher complications and anterior knee pain.
Source: Freedman KB, et al. Arthroscopic anterior cruciate ligament reconstruction: A meta-analysis comparing patellar tendon and hamstring tendon autografts. Am J Sports Med. 2003;31(1):2-11.
Autograft patellar or hamstring tendons are the most common choices of graft for ACL reconstructions, and both have been used with good success. Although some prospective, randomized studies comparing the 2 grafts are emerging, as follows this paper in the same journal issue, numbers of patients tend to be too small to draw meaningful conclusions. As Freedman and colleagues found in the present meta-analysis of the 2 methods covering 34 years and involving 1348 patellar tendon patients and 628 hamstring patients, it would take nearly 1200 patients in a randomized trial to have sufficient power given the differences they observed between groups.
Therefore, Freedman et al performed a literature review analyzing ACL reconstruction using either autograft with a minimum patient follow-up of 2 years. They found the patellar tendon graft patients had more stable knees (< 3mm side-to-side difference on KT-1000 was 79% patellar vs 73.8% hamstring) and a lower failure rate (1.9% patellar vs 4.9% hamstring). However, this came with a price, as the patellar group had a higher complication rate for manipulation or lysis of adhesions (6% vs 3%) and more anterior knee pain (17% vs 11%). Yet, hardware removal was more common in the hamstring group.
Comment by David R. Diduch, MS, MD
No question about it—both patellar tendon and hamstring autografts work fine for ACL reconstruction. However, each of us has our preferences as do our patients. Freedman et al make an excellent point through which we should interpret other papers to follow: It would take prohibitively huge numbers of patients to detect any meaningful differences between the 2 groups in a prospective study given how well both groups do.
Although there are definite weaknesses to a metaanalysis and we are cautioned to reading too much into the results, the study does reinforce differences between the groups that I believe are real and which we can share with our patients at decision time. Patellar tendon grafts are slightly tighter and have a slightly lower failure rate. It is important to remember that hamstring fixation has evolved much more than the tried and true interference screw for the patellar tendon grafts. It would be interesting to do a similar meta-analysis covering only the past 3-5 years with more modern fixation methods. Nevertheless, given the constant improvements in fixation methods, it is safe to conclude that both grafts are acceptable.
For me, then, the decision with the patient tends to involve the presence of pre-existing anterior knee pain (prefer hamstring), concerns about the size of the scar, the need for the tightest knee possible and early return to sports (patellar graft), or an early return to work (hamstring graft). At some level, the surgeon also needs to factor in what they can do best, although in 2003 it is probably best that a surgeon routinely doing ACLs be competent in both techniques.
Dr. Diduch is Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA
Although both grafts yielded acceptable results in a large literature meta-analysis, patellar tendon grafts tended to result in slightly more stable knees with a lower failure rate but at the expense of higher complications and anterior knee pain.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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