Investigators reach stalemate about ACL graft selection data

Prospective randomized trial comparing three tendons, few differences found.

Issue: July 2004

ESSKA [logo] Orthopedic surgeons who practice sports medicine typically agree that autograft tendons perform extremely well for arthroscopic anterior cruciate ligament reconstructions.

However, many clinicians have strong preferences regarding which autograft tendons are best to use and why.

Surgeons from Australia, Sweden, Italy, Germany, Greece and the United States presented new data and varying perspectives on which grafts perform best for this purpose during the 11th ESSKA Congress.

Results of a comparative study presented by Gauti Laxdal, MD, demonstrated that, in some cases, using three- and four-strand semitendinosus autografts was preferable to using bone- central patellar tendon-bone constructs (BTB) for arthroscopic anterior cruciate ligament (ACL) reconstruction. Patients felt significantly less discomfort with those grafts at two years postop during the knee walking test, yet investigators saw no statistically significant functional differences between the three types of grafts at follow-up.

Patellar tendon performance

“The knee walking test in the BTB group was significantly worse at follow-up compared to the preoperative assessment,” said Laxdal, who is in the department of orthopedics at Sahlgrenska University Hospital, Östra, Sweden.

Investigators randomized 134 patients with unilateral ACL ruptures into three surgical groups and prospectively followed them. The patients were treated using an all-inside technique and different tendon autografts.

After 16 patients were excluded or dropped out of the study, 118 patients remained, leaving 40 patients in the BTB group and 39 patients each in the groups that received three-strand semitendinosus tendons (ST) or four-strand semitendinosus gracilis tendons (STG).

The demographics were highly similar among patients in all three groups, he said. Mean follow-up was approximately the same: 25.5 months, 27 months and 26 months for patients in the BTB, ST and STG groups, respectively.

Patients in the STG group had better results with one test. “The follow-up of the WOMAC hop test showed significantly better result in the STG group compared to the BTB and ST groups,” Laxdal said. Researchers found good to excellent results in 99% in the STG group vs. 94% in the BTB group and 93% in the ST group.

Side-to-side differences

Patients in all groups achieved side-to-side differences of 1 mm or 2 mm with the KT-1000 test, although 56% of the patients in the BTB group found the postoperative knee-walking test either difficult or impossible to complete compared to 5% of patients in the STG group (P<.0001) and 25% in the ST group (P=.0004).

“At two-year follow-up after the ACL reconstruction, we were not able to show any differences regarding functional results or knee laxity between the three groups,” Laxdal said.

In a presentation detailing his clinical experience reconstructing ACLs arthroscopically, Argiris Mitsou, MD, at the Hellenic Sports Research Institute in Athens, discussed why he prefers to use hamstring tendons.

From 1982 to 1997, Mitsou used patellar tendons (PT) for arthroscopic ACL reconstruction in 95% of his patients; however, he sought a better solution after his athletic patients, many of whom played sports professionally, complained of pain and reduced function.

He switched to using the hamstring tendon, which is stronger, he said. Its strength “is close to two and a half times more than the PT graft.” Hamstrings also have increased stiffness and demonstrate superior resistance to stretching — nearly twice that of PT grafts, Mitsou said.

It also has surgical advantages. The procedure typically involves same-day or one-day surgery.

“There is smoother recovery [with the hamstring tendon],” Mitsou said. In general, harvesting hamstrings is less traumatic and produces less morbidity. Postoperatively there is “no absence of the patellar tendon, no fracture of the patella.” The risk for muscle weakness is also greatly reduced.

Richard J. Steadman, of Vail, Colo., is a proponent of patellar tendon autografts for ACL reconstruction. By properly positioning the tunnels (top left), surgeons can optimize the graft tendon’s length. Undergoing a notchplasty in the area indicated here (bottom left) has helped avoid impingement of autografts, which reduce their strength. Patellar mobilization (above right) is the key to avoid scarring and joint stiffness.

COURTESY OF RICHARD J. STEADMAN

Two-incision technique

The PT is the ACL graft of choice for Richard J. Steadman, MD, of Vail, Colo., who stated that good tunnel placement and sufficient tendon fixation in the tunnels are important to achieving optimal outcomes in patients.

“I think another issue is impingement. If you leave the graft in a position where it can impinge, then over time that makes the graft weaker and may make the patient more subject to failure,” he said.

The main goal of an ACL reconstruction is to restore the same soft tissue biomechanics found in the contralateral knee, Steadman said. He uses a two-incision technique because it gives him a better angle for inserting the femoral component than is obtainable with one incision. A 45° tibial entry angle can also be readily obtained.

“Posterior position is very important in maintaining the graft length through the range of motion. … I like the strength of the graft with that technique, bone to bone fixation and healing,” he said. “And, the tendon site does regenerate.”

Another advantage of the two-incision technique is that surgeons can use any length of graft they want. Likewise, the technique is reproducible, and the posterior position can be easily checked.

To avoid pain after tendon harvesting, he suggested that patients avoid excessive strain in the first six to 12 weeks and manually moving the patella. PT should start the first postoperative day and continue for three months. Anterior knee pain may be avoided by filling the bone defects that result from tendon harvest.

For more information:

Laxdal G, Kartus J, Hansson L, et al. Patellar tendon or multiple-strand hamstring tendon autografts for anterior cruciate ligament reconstruction? A prospective randomized study using three different graft types with a two-year follow-up. #86. Presented at the 11th ESSKA Congress and 4th World Congress on Sports Trauma. May 5-8, 2004. Athens.

Mitsou A. Clinical Corner 1: Why I use hamstring tendons for ACL reconstruction. Presented at the 11th ESSKA Congress and 4th World Congress on Sports Trauma. May 5-8, 2004. Athens.

Steadman RJ. Clinical Corner 2: Why I use patellar tendons for ACL reconstruction. Presented at the 11th ESSKA Congress and 4th World Congress on Sports Trauma. May 5-8, 2004. Athens.