Achilles tendon healing: A correlation between functional and mechanical performance in the rat

Thomas M. Best, Alison Collins, Edward G. Lilly, Anthony V. Seaber, Richard Goldner, George A.C. Murrell

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


The pathogenesis and treatment of rupture of the Achilles tendon remain a source of controversy. This study presents the results of a biomechanical, functional, and morphological evaluation of a group of rats that had division and repair of the Achilles tendon. A total of 46 rats were used: 18 for biomechanical testing, 18 for functional evaluation, and 10 for histology. Morphological examination revealed an early inflammatory response with loose connective tissue formation that was replaced gradually by fibroblasts and a collagenous matrix. The functional evaluation (Achilles functional index [AFI]) was made from measurements of the hind pawprints of walking rats. Division and repair of the Achilles tendon produced a significant functional impairment (mean [±SEM] AFI = −87 ± 8; p < 0.001), which gradually improved with healing time. The load to failure for the repaired tendons consistently improved with healing time, in a manner similar to the functional recovery. The average deformation (repair/control) varied considerably and was not related to healing time. The stiffness of the repaired tendons increased with healing time and was 60% of the corresponding control side by day 15. The major finding of this study was a strong correlation between the AFI and the failure load of the healing tendon‐bone constructs (250–300 g group, r = 0.97, p < 0.001; 325–375 g group, r = 0.96, p < 0.001).

Original languageEnglish (US)
Pages (from-to)897-906
Number of pages10
JournalJournal of Orthopaedic Research
Issue number6
StatePublished - Nov 1993
Externally publishedYes

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


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