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New segmental long bone defect model in sheep: Quantitative analysis of healing with dual energy X‐ray absorptiometry
Author(s) -
den Boer Frank C.,
Patka Peter,
Bakker Fred C.,
Wippermann Burkhard W.,
van Lingen Arthur,
Vink Ger Q. M.,
Boshuizen Klaas,
Haarman Henk J. Th. M.
Publication year - 1999
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.1100170506
Subject(s) - intramedullary rod , bone healing , bone mineral , nonunion , dual energy x ray absorptiometry , tibia , medicine , bone grafting , dual energy , radiography , bone mineral content , nuclear medicine , anatomy , dentistry , surgery , pathology , osteoporosis
Abstract An appropriate animal model is required for the study of treatments that enhance bone healing. A new segmental long bone defect model was developed for this purpose, and dual energy x‐ray absorptiometry was used to quantify healing of this bone defect. In 15 sheep, a 3‐cm segmental defect was created in the left tibia and fixed with an interlocking intramedullary nail. In seven animals, the defect was left empty for the assessment of the spontaneous healing response. In eight animals serving as a positive control, autologous bone grafting was performed. After 12 weeks, healing was evaluated with radiographs, a torsional test to failure, and dual energy x‐ray absorptiometry. The mechanical test results were used for the assessment of unions and nonunions. Radiographic determination of nonunion was not reliably accomplished in this model. By means of dual energy x‐ray absorptiometry, bone mineral density and content were measured in the middle of the defect. Bone mineral density was 91 ± 7% (mean ± SEM) and 72 ± 6% that of the contralateral intact tibia in, respectively, the autologous bone‐grafting and empty defect groups (p = 0.04). For bone mineral content, the values were, respectively, 117 ± 18 and 82 ± 9% (p = 0.07). Torsional strength and stiffness were also higher, although not significantly, in the group with autologous bone grafting than in that with the empty defect. Bone mineral density and content were closely related to the torsional properties (r 2 ranged from 0.76 to 0.85, p ⩽ 0.0001). Because interlocking intramedullary nailing is a very common fixation method in patients, the newly developed segmental defect model has clinical relevance. The interlocking intramedullary nail provided adequate stability without implant failure. This model may be useful for the study of treatments that affect bone healing, and dual energy x‐ray absorptiometry may be somewhat helpful in the analysis of healing of this bone defect.