2015 ISAKOS Biennial Congress ePoster #1312

Femoral Tunnel Enlargement Progress in Early Stage After Anterior Cruciate Ligament Reconstruction: CT Study

Ryo Shimizu, MD, Hiroshima JAPAN
Nobuo Adachi, MD, PhD, Hiroshima JAPAN
Masataka Deie, MD, PhD, Prof., Nagakute, Aichi-Ken JAPAN
Atsuo Nakamae, MD, PhD, Hiroshima JAPAN
Masakazu Ishikawa, MD, PhD, Hiroshima JAPAN
Tomoyuki Nakasa, MD, PhD, Matsuyama JAPAN
Yasunari Ikuta, MD, PhD, Hiroshima JAPAN
Mitsuo Ochi, MD, PhD, Higashi, Hiroshima JAPAN

Hiroshima University, Hiroshima, Hiroshima, JAPAN

FDA Status Not Applicable

Summary: The purpose of this study is to evaluate tunnel enlargement in early stage after double bundle ACL reconstruction using CT image. The tunnel enlargement ratio is especially higher first 1 months after operation despite of the period of immobilization. The tunnel enlargement ratio of posterolateral bundle was greater than that of anteromedial bundle.

Rate:

Abstract:

Objective

Previously, it was reported that tunnel enlargement develops after anterior cruciate ligament (ACL) reconstruction. Although bone tunnel enlargement after ACL reconstruction is quite essential issue because it may often related to joint stability and clinical outcome, the factor of tunnel enlargement associated with ACL reconstruction has not been well understood. Most authors advocated that biomechanical and biological factors might lead to tunnel enlargement. Recently CT image is generally available and it is easy to assess the tunnel enlargement more visually and quantitatively. However, there is few report which evaluate the tunnel enlargement in relatively early stage after operation. The purpose of this study is to evaluate tunnel enlargement in early stage after double bundle ACL reconstruction using CT image.

Method

This is a prospective cohort study using CT image. We evaluate 20 cases who underwent double bundle ACL reconstruction with hamstring tendon autograft. The mean age of patients is 29.4 years old. 10 patient with meniscus injury underwent meniscus suture at the same time. In all cases, femoral tunnel was drilled through far anteromedial portal technique. The graft was fixed by EndoButton CL at femoral side and double stapling technique was used at tibial side. After operation, in 10 patients who underwent arthroscopic meniscus suture, the operated knees were immobilized for 2 weeks and the others were immobilized for 3days. CT scan was performed at within 3 days after operation, 2 weeks, 1 month, 3 months, and 6 months. We measured the area of anteromedial femoral tunnel (AMFT), posterolateral femoral tunnel (PLFT) at the 4 slices which were adjusted to same distance from Endobutton in all case.

[Result] Tunnel enlargement was observed in all cases. For 6 months the mean enlargement ratio of AMFT and PLFT at the nearest slice of tunnel aperture were 82.0% and 119% respectively. Duration specific enlargement ratio of AMFT and PLFT were 43.5%, 54.6% from immediate after operation to 2 weeks, 35.0%,57.9% from 2 weeks to 1month, 1.10%, 2.00% from 1 month to 3 months, and -8.00% and -7.70% from 3 months to 6 months respectively. There were significant differences of the enlargement ratio between AMFT and PLFT from 2 weeks to 1 month, 1 month to 3 months, and 3 months to 6 months, but was no significant difference from immediate after operation to 2 weeks. There were also no significant differences of tunnel enlargement ratio of AMFT and PLFT between 3 days and 2 weeks immobilization groups.

Conclusion

It was very interesting that bone tunnel enlargement of AMFT and PLFT were developing immediately after operation. The tunnel enlargement ratio is especially higher first 1 months after operation. The tunnel enlargement ratio of PLFT was greater than that of AMFT after 2 weeks to 6 months. Despite of immobilization after operation, the tunnel enlargement was developing in early stage.