Navigation effective in ACL reconstruction trial

Researchers saw no difference in patient satisfaction or return to sport between the navigation and control groups.

Anterior cruciate ligament reconstruction performed using a computer-assisted navigation system produced less varied radiological laxity and more consistent tunnel positions compared to standard, non-navigated procedures, a recent study found.

Computer-assisted navigation provides more precision and reproducibility in selecting tunnel positions, ultimately yielding better results, co-investigator Philip Rosell, FRCS, said at the British Orthopaedic Association Annual Congress.

Rosell and colleagues performed a prospective, randomized, controlled study of 60 patients undergoing ACL reconstruction by either conventional methods or using computer navigation. The researchers sought to determine how surgical navigation could improve ACL outcomes in light of poor results related to imperfect tunnel positioning.

Senior author Stephane Plaweski, MD, an orthopedic surgeon from Grenoble, France, performed all procedures using a four-strand hamstring graft with endloop and interference screw fixation. He excluded patients with bilateral injuries or additional ligament injuries.

Good outcomes, no failures

Researchers analyzed laxity and tunnel positions after three, six, 12 and 24 months using IKDC forms and standard radiographs. Patients who underwent surgery with navigation showed significantly less laxity variation (P=.0003) and more consistent tunnel positioning (P=.03) compared to conventionally treated patients.

However, at two years follow-up, the researchers found no differences in function between the two groups, “and our only differences were found on measurements of laxity using standard radiological Telos measurements and in the accuracy of tibial tunnel positions,” Rosell told Orthopedics Today.

IKDC laxity was level A in the conventionally treated group of 22 knees, averaging 1.5 mm at 200 N. The IKDC laxity level was 1.3 mm in the navigation-assisted group of 26 knees. Laxity measured less than 2 mm in 96.7% of the navigated group and 83% in the conventional, non-navigated group, according to the abstract.

“There were no clinical failures in either group and no difference in terms of functional outcome, satisfaction or return to sporting activity,” Rosell said.

“The main difference detected was the variability of the results, with the navigated results being more closely concentrated in the lower end of the range of laxity measurements. There was also a difference in the accuracy of tibial tunnel placement with the navigation system, which allowed a more consistent result,” he said.

Surgeons calibrate their instruments for computer-assisted navigation while performing ACL reconstruction. Navigation afforded lower laxity and more accurate tibial placement than conventional techniques.

Plaweski and colleagues use the Surgetics station (Praxim medivision) for computer-assisted navigation during ACL reconstruction.

COURTESY PHILIP ROSELL

Advocating navigation as the standard

Rosell noted that navigation did increase operation time, but caused no additional complications. He suggested navigation become a standard surgical technique.

“Based on these results, we would suggest that the use of navigation is justified as a routine technique, even in the hands of an experienced surgeon, as the tunnel positions are more consistent and a more accurate reconstruction can be expected,” he said.

“The question that remains is whether the long-term graft viability will be improved. We intend to revisit this group of patients at the five- and 10-year points to try and answer this question,” he added.

For more information:
Rosell P, Plaweski S, Cazal J, Merloz P. The efficacy of navigation for anterior cruciate ligament reconstruction. Presented at the British Orthopaedic Association Annual Congress. Sept. 20-23, 2005. Birmingham, England.