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Updated: Jun 14, 2026
Establishment and Evaluation of a Sheep Model of Full-thickness Osteochondral Defect
Published on: April 14, 2026
The relation between tunnel widening and bone mineral density after anterior cruciate ligament reconstruction: an
Rupert Meller1, Alexandra Neddermann, Elmar Willbold
1Trauma Department, Hannover Medical School, Hannover, Germany. meller.rupert@mh-hannover.de
Purpose:
The aim of this study was to analyze the relation between bone mineral density (BMD) and femoral tunnel enlargement (TE) in a previously validated sheep model of soft-tissue anterior cruciate ligament (ACL) reconstruction.
Methods:
Thirty sheep underwent ACL reconstruction by use of a soft-tissue graft at the age of 4 months. Graft fixation was achieved with the EndoButton (Smith & Nephew Endoscopy, Andover, MA) and Suture Washer (Smith & Nephew Endoscopy). Six animals were killed at 0, 3, 6, 12, and 24 weeks postoperatively. Each ACL-reconstructed knee was examined both by computed tomography to analyze the bone tunnel cross-sectional area and by dual-energy x-ray absorptiometry to analyze BMD.
Results:
There was a significant increase in tunnel cross-sectional area. BMD decreased significantly within the first 3 weeks after surgery and increased thereafter. A positive correlation between TE and BMD was found. However, a subgroup analysis showed that there is no influence of BMD on the development of a tunnel widening.
Conclusions:
The hypothesis that a TE would be associated with a loss in BMD was not confirmed. Tunnel widening during the first 6 months after ACL reconstruction is not affected by the transient changes in BMD.
Clinical Relevance:
There is no correlation between TE and BMD in an experimental sheep model of ACL reconstruction. Translational investigations will determine whether this is also true in humans.