A Canine Model of Femoral Head Osteonecrosis Induced by an Ethanol Injection Navigated by a Novel Template

Abstract

There is no consensus on how to establish models of osteonecrosis of the femoral head (ONFH) in large mammals. The aim of this study was to investigate the effectiveness of a novel canine model of ONFH, induced by a navigated injection of absolute ethanol. Using three-dimensional reconstruction and rapid prototyping manufacturing techniques, a new template was designed and processed to navigate the ethanol injection. The femoral heads of 18 adult dogs were injected with ethanol. Macroscopic, X-ray and histological examinations were performed at 3, 6, and 9 weeks after the operation. Further, computed tomography (CT), magnetic resonance imaging (MRI), and radionuclide scans were performed 6 weeks postoperatively. Three weeks after the operation, the femoral heads showed evidence of osteonecrosis including increasing numbers of empty lacunae, decreased hematopoietic cells, and destroyed adipose tissue in the medullary cavity, which increased in severity at the subsequent follow-up evaluations at 6 and 9 weeks. Fractured trabeculae and fibrous tissue were noted 9 weeks postoperatively. Image analysis also revealed evidence of osteonecrosis, such as several osteopenic areas with sclerotic rims on the X-ray, several areas of low bone mineral density with sclerosis on the CT scan, increased uptake of the nuclide species in MRI, and an inhomogeneous long T2 signal on the radioisotopic images. Ethanol injection navigated by our novel template was successful in establishing a canine model of ONFH. This model can be used to test new treatment modalities for human ONFH.

Computation of Femoral Canine Morphometric Parameters in Three‐Dimensional Geometrical Models

“…Although 3D models are a well‐established diagnostic tool for people, they are new to veterinary medicine. Recent efforts to develop consistent imaging techniques led to a 3D approach for veterinary orthopedic investigation . The 3D models allow volume measurement, evaluation of joint congruency, and rotation of deformed bones at a desired orientation, creating cross‐sectional views from any position .…”

“…Recent efforts to develop consistent imaging techniques led to a 3D approach for veterinary orthopedic investigation. [36][37][38][39][40][41][42][43][44][45][46] The 3D models allow volume measurement, 37 evaluation of joint congruency, 36,38 and rotation of deformed bones at a desired orientation, creating cross-sectional views from any position. 42 Only a single recent study has evaluated bone deformities through CT scan-reconstructed 3D images but provided femoral measurements calculated in CT frontal or lateral view, thus in biplanar projections.…”

“…The 3D femoral surface models can be constructed with data acquired from biplanar radiographs, CT, MR, and surface meshing software . Computation on 3D geometric models has been recently introduced as a source of reliable data for investigating canine hip joint osteoarthritic degeneration, designing bone templates, analyzing the femoral surface, and also for in vivo kinematics research …”

“…The 3D femoral surface models can be constructed with data acquired from biplanar radiographs, 27,28 CT, 29,30 MR, 31 and surface meshing software. [32][33][34][35] Computation on 3D geometric models has been recently introduced [36][37][38][39][40][41][42][43][44][45][46] as a source of reliable data for investigating canine hip joint osteoarthritic degeneration, [36][37][38] designing bone templates, [39][40][41] analyzing the femoral surface, [42][43][44] and also for in vivo kinematics research. 45,46 The assessment of 3D canine femoral axes and angles is currently not reported in veterinary medicine.…”

Knee loading protects against osteonecrosis of the femoral head by enhancing vessel remodeling and bone healing

“…There are several etiologic risk factors such as trauma [3, 4], excessive corticosteroid use [5–7], excessive alcohol intake [8], Legg-Calve-Perthes disease [9, 10], etc. Debilitated blood supply to the femoral head commonly leads to necrosis and collapse of the femoral head [11].…”