Size One of Many Factors Determining ACL Reconstruction Outcomes

In anterior cruciate ligament reconstruction, size doesn’t necessarily matter.

Recent data show no significant differences in functional outcomes between anterior cruciate ligament (ACL) reconstructions that use quadruple hamstring autografts measuring 7 millimeters or less and those using grafts of 7.5 millimeters or larger. And despite a higher rupture rate among the smaller autografts, many of them are not revised.

“Certainly, some small grafts do well, and size is not the only factor. Other factors must be considered—particularly, age, sport and athletic activity,” said Fintan J. Shannon, M.D., a surgeon at the University College Hospital in Galway, Ireland.

To investigate the role of hamstring autograft size on the outcomes of primary ACL reconstruction, Shannon and several of his colleagues reviewed a single surgeon’s series of 314 patients with a minimum 18 months follow-up who were surveyed about function and satisfaction through telephone and mail. The primary study outcome was ACL graft failure confirmed clinically or by MRI. Overall, 40 percent of the grafts studied measured 7 millimeters or less, and 60 percent of grafts measured 7.5 millimeters or more.

“We had three deep acute infections within two weeks of surgery. All were successfully revised using BTB [bone-tendon-bone] grafts,” Shannon said.

The researchers observed a total of 14 graft ruptures, which occurred in patients with an average age of 27 years.

“There were three patients less than or equal to 20 years of age. When we looked at them in terms of the total number, there was some suggestion that there was a higher failure rate in these younger patients, but this was not significant,” Shannon noted.

Of the 14 ruptures, 10 occurred in cases that used grafts measuring 7 millimeters or less. However, Shannon noted that overall, most small grafts in the study were functioning and had not been revised.

Of the 117 patients who responded to questionnaires, the researchers found similar patient satisfaction between the groups, and no significant differences were observed between the groups for Lysholm and Lower Extremity Functional Scores.