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Tendon to bone tunnel healing—A study on the time‐dependent changes in biomechanics, bone remodeling, and histology in a rat model
Author(s) -
Hjorthaug Geir Aasmund,
Madsen Jan Erik,
Nordsletten Lars,
Reinholt Finn P.,
Steen Harald,
Dimmen Sigbjorn
Publication year - 2015
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.22756
Subject(s) - biomechanics , tendon , bone healing , histology , medicine , connective tissue , tibia , anatomy , achilles tendon , bone mineral , bone density , soft tissue , surgery , pathology , osteoporosis
Tendons and ligaments attach to bone through a transitional connective tissue with complex biomechanical properties. This unique tissue is not regenerated during healing, and surgical reattachment therefore often fails. The present study was designed to evaluate tendon healing in a bone tunnel and to evaluate the utilized rat model. Wistar rats ( n = 61) were operated with the Achilles tendon through a bone tunnel in the distal tibia. Healing was evaluated at 2, 3, 4, and 12 weeks by biomechanical testing, bone mineral density and histology. After 2 weeks median (interquartile range) pull‐out force was 2.2 N (1.9). The pull‐out force increased chronologically, by 12 weeks fivefold to 11.2 N (11.4). Energy absorption, stiffness, and bone mineral density increased similarly. The histological analyses showed inflammation at early stages with increasing callus by time. Our data showed a slow healing response the first 4 weeks followed by an accelerated healing period, favoring that most of the gain in mechanical strength occurred later than 4 weeks postoperatively. These findings support the concern of a vulnerable tendon bone tunnel interface in the early stages of healing. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:216–223, 2015.