Surgeons recommend using a single-tendon technique for ACL reconstruction

Internal rotation weakness and deep flexion deficit noted in semitendinosusand gracilis patients.

Issue: July 2006

CHICAGO – ACL reconstruction using the semitendinosus tendon alone yields similar results to ACL reconstruction with the semitendinosus and gracilis tendons, researchers confirmed.

In a prospective study, researchers compared patients treated with ACL reconstruction using one tendon or two tendons. They found no significant difference between the two groups in clinical evaluation, International Knee Documentation Committee (IKDC) scores or isokinetic strength deficits of the hamstrings and quadriceps.

Alberto Gobbi, MD [photo]
Alberto Gobbi

However, “Internal rotation weakness [and] deep flexion deficit were noted in the semitendinosus and gracilis [patients],” said Alberto Gobbi, MD, of OASI Research Center in Milan, Italy.

Gobbi recommends the one-tendon technique because preserving the gracilis could reduce morbidity after harvesting the hamstring tendons. “The gracilis may compensate for semitendinosus function and it should be preserved during ACL reconstruction,” he said at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting.

Patient data

Gobbi and his fellow, Ramces A. Francisco, MD, prospectively evaluated 97 patients at an average 36-month follow-up (range, 24 months to 70 months).

One surgeon performed the four-stranded hamstring tendon ACL reconstruction using the semitendinosus alone as a quadrupled graft on 50 patients (ST group), and used a doubled semitendinosus and doubled gracilis tendon in another 47 patients (STG group).

The ST group included 31 men and 19 women with an average age of 31 years, while the STG group included 26 men and 21 women with an average age of 28.8 years. In both groups, the mean interval from injury to surgery was 5 months.

All patients underwent the same rehabilitation protocol, all were active athletes and the two groups were comparable in surgical time, hospitalization and graft preparation, Gobbi said.

Few significant differences

Researchers found no significant difference (P>.05) in the average knee scores between the two groups, as follows:

Lysholm: 95 in the ST group and 94 in the STG group,
Tegner: 7.4 in the ST group and 6.5 in the STG group,
Noyes: 85 in the ST group and 82 in the STG group,
Subjective score: 89% in the ST group and 87% in the STG group.

IKDC scores revealed that 96% of the ST group patients had normal or nearly normal knees, with 4% abnormal or severely abnormal. In the STG group, 91% were labeled normal or nearly normal, with 9% abnormal knees. Again, the researchers found no significant difference (P=.54).

In 90% of all patients, researchers found less than a 3-mm side-to-side difference in anterior/posterior (AP) translation, according to the meeting abstract.

“We found comparable computerized laxity tests with more than 80% of these patients within 2 mm,” Gobbi said. “And the one-leg hop and ergo jump tests showed no significant difference.”

Difference in internal rotation

“The gracilis may compensate for semitendinosus function and it should be preserved during ACL reconstruction.”
— Alberto Gobbi, MD

In the isokinetic test, Gobbi said they found no significant difference in peak flexion/extension torque deficit at 3 months, 5 months or 1 year.

“But with peak rotational torque deficit, we found internal rotation deficit higher in the semitendinosus and gracilis (P=.039), while no difference in external rotation was found,” Gobbi said.

They also found a loss of deep flexion in the STG group with the Nakamura test, he said.

“Internal rotation weakness and the possible effect on sport activities is very important,” Gobbi said. “More investigation [is] necessary to assess the side effect associated with the use of semitendinosus and gracilis, especially in particular sports where deep flexion and internal rotation strength is important.

For more information:
Gobbi A, Francisco R. Hamstring tendon ACLR: Advantages and disadvantages of using ST versus STG. #020. Presented at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting. March 22-26, 2006. Chicago.