The preclinical sheep model of high tibial osteotomy relating basic science to the clinics: Standards, techniques and pitfalls

Dietrich Pape*, Henning Madry

*Corresponding author for this work

    Research output: Contribution to journalArticleResearchpeer-review

    26 Citations (Scopus)


    Purpose: To develop a preclinical large animal model of high tibial osteotomy to study the effect of axial alignment on the lower extremity on specific issues of the knee joint, such as in articular cartilage repair, development of osteoarthritis and meniscal lesions. Preoperative planning, surgical procedure and postoperative care known from humans were adapted to develop a HTO model in the adult sheep. Methods: Thirty-five healthy, skeletally mature, female Merino sheep between 2 and 4 years of age underwent a HTO of their right tibia in a medial open-wedge technique inducing a normal (group 1) and an excessive valgus alignment (group 2) and a closed-wedge technique (group 3) inducing a varus alignment with the aim of elucidating the effect of limb alignment on cartilage repair in vivo. Animals were followed up for 6 months. Results: Solid bone healing and maintenance of correction are most likely if the following surgical principles are respected: (1) medial and longitudinal approach to the proximal tibia; (2) biplanar osteotomy to increase initial rotatory stability regardless of the direction of correction; (3) small, narrow but long implant with locking screws; (4) posterior plate placement to avoid slope changes; (5) use of bicortical screws to account for the brittle bone of the tibial head and to avoid tibial head displacement. Conclusion: Although successful high tibial osteotomy in sheep is complex, the sheep may-because of its similarities with humans-serve as an elegant model to induce axial malalignment in a clinically relevant environment, and osteotomy healing under challenging mechanical conditions.

    Original languageEnglish
    Pages (from-to)228-236
    Number of pages9
    JournalKnee Surgery, Sports Traumatology, Arthroscopy
    Issue number1
    Publication statusPublished - Jan 2013


    • Alignment
    • Cartilage repair
    • High tibial osteotomy
    • Pitfalls
    • Preclinical large animal model


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