Increased age, autograft use show lower graft rupture rate after ACL reconstruction

With either allograft or autograft reconstruction, the risk of tear decreases with increasing patient age.

Issue: November 2008

AOSSM

The results of a prospective, multicenter, longitudinal study identified graft type and age as independent predictors for ACL reconstruction failure.

To evaluate the risk of graft rupture after ACL reconstruction using tibialis allograft compared to hamstring autograft and to identify the variables for graft failure, Christopher C. Kaeding, MD, and colleagues studied 289 ACL reconstructions with 2-years minimum follow-up that were performed by a single surgeon participating in the multicenter orthopaedic outcome network (MOON) study.

After indentifying the significant predictors for graft failure, the investigators then validated the single-surgeon model with the entire MOON dataset of nearly 700 ACL reconstructions by analyzing the percent change in the predictors.

Higher activity level

The investigators identified the Marx activity score at the time of the index injury, age and graft type as significant predictors for graft failure in the single-surgeon model. “For the single-surgeon model, higher level of activity at the index injury relates to an increased chance of re-tear,” Kaeding said during his presentation at the American Orthopaedic Sports Medicine Society 2008 Annual Meeting. Allograft reconstruction increased the chance of re-tear, increased age decreased the chance of re-tear and gender was not a risk factor.

However, the investigators found that the Marx activity score at the time of the index injury was not a significant predictor for the larger group of surgeons participating in the MOON study. “In the final Moon model, graft type and age were significant independent predictors of re-tear,” Kaeding said.

Single-surgeon model

Patients with an allograft reconstruction had an Odds Ratio of 6.77 for failure compared to autograft patients. Older patients had an Odds Ratio of 0.45 for rupture compared to those who were a decade younger.

The single-surgeon model included 166 allograft and 123 autograft reconstructions. The surgeon used an identical surgical technique, postoperative rehabilitation and return to play guidelines for both. The investigators found 24 cases of graft rupture in the allograft group and six cases in the autograft group.

After controlling for age and graft type, they found that for every four-point increase in the Marx activity score, the odds of graft rupture increased nearly threefold in the single-surgeon model.

Controlling for Marx activity score and graft type, revealed that every increased decade in patient age decreased the odds of a tear by about half. Conversely, each decreased decade in age doubled the odds for a tear in the single-surgeon model.

“When we looked at graft type and controlled for age and activity, the odds of re-tear for allograft versus autograft was almost five times,” Kaeding said.

Using the single-surgeon model, investigators predicted that an active, 18-year-old patient who underwent an allograft reconstruction has a 20% change of graft rupture compared to a 5% to 6% chance of rupture with an autograft. A less active, 40-year-old patient who receives an allograft has less than a 3% chance of re-tear versus less than a 1% chance of rupture with an autograft.

For more information:

Christopher C. Kaeding, MD, can be reached at Ohio State University Sports Medicine Center, 2050 Kenny Road, Pavilion Suite 3100, Columbus, OH 43221; 614-293-3600; e-mail: christopher.kaeding@osumc.edu. He has no disclosures relating to this article, and that the study was partially funded by an NIH grant.

Reference:

Kaeding CC, Pedroza A, Aros BC, et al. Independent predictors of ACL reconstruction failure from the MOON prospective longitudinal cohort. Presented at the American Orthopaedic Society for Sports Medicine. July 10-13, 2008. Orlando, Fla.