The purpose of our study was to investigate whether the preoperative measurement of the semitendinosus tendon using ultrasonography would help in the intraoperative decision regarding the need to harvest the gracilis tendon in double-bundle anterior cruciate ligament reconstruction which aims to make two grafts with diameters of >4.5mm each.
Arthroscopic anatomical double-bundle anterior cruciate ligament reconstruction (DB-ACLR) has become increasingly common of late. Ipsilateral hamstring tendons were ordinarily used as autografts in DB-ACLR. If the volume of the semitendinosus (ST) tendon was not enough, the gracilis (G) tendon would be harvested additionally. This judgment would be made intraoperatively. Is it possible to judge this before surgery?
The aim of our study was to investigate whether the preoperative measurement of the ST tendon using ultrasonography would help in the intraoperative decision regarding the need to harvest the G tendon.
Twelve patients who underwent DB-ACLR between October 2017 and August 2018 were included in the study. The mean patient age at surgery was 29.3 ± 11.3 years. The patients included 7 men and 5 women. All the surgeries were primary surgeries, and patients with a history of trauma of the hamstrings were excluded. We measured the ST tendon using ultrasonography 1 day before surgery. The measurements included the diameter and breadth of the short-axis image at crease level behind the knee. During surgery, the ST tendon was harvested first. In case it was not possible to make two grafts with diameters of >4.5 mm each, the G tendon was harvested additionally.
The patients were categorized into two groups as follows: in group ST, only the ST tendon was harvested and in group STG, the G tendon was harvested additionally. The preoperatively measured data were compared between the two groups.
Group STG included six cases and group ST included six cases. In group ST, the mean preoperative diameter and breadth of the ST tendon were 4.30 ± 0.16 and 2.30 ± 0.37 mm, respectively. In group STG, the mean preoperative diameter and breadth of the ST tendon were 3.38 ± 0.78 and 1.68 ± 0.25 mm, respectively. The cross-sectional area (CSA) calculated from these measurements was 7.82 ± 1.26 mm2 in group ST and 4.53 ± 1.27 mm2 in group STG. The CSA of group ST was significantly larger than that of group STG.
If the cutoff value was defined as 8 mm2 in this study, the specificity was 100% and the sensitivity was 83.3%.
Ultrasonography is minimally invasive, convenient, and low-cost. We use only the ST tendon in DB-ACLR if it can yield two double-strand autografts of diameter > 4.5 mm each. We defined 8 mm2 of CSA as the cutoff value because the area of a 4.5-mm diameter circle is approximately 15.9 mm2. This value was not very different from that obtained using the receiver-operating characteristic curve. The measurements in our study were smaller than those in previous research studies. This might be caused by the difference in skeletal muscle between Japanese and them.
The preoperative CSA of the ST tendon determined using ultrasonography could be used as a reference for deciding whether to harvest the G tendon or not in DB-ACLR.