title: Experimental confirmation of the sheep model for studying the role of calcified fibrocartilage in hip fractures and tendon attachments.
abstract: Research has shown that there is a dramatic increase in the fractional area of calcified fibrocartilage from tendon and capsular insertions on the human femoral neck (Vajda and Bloebaum, 1999; Shea et al., 2001b). Additional information regarding the properties of the proximal femur's cortical shell, gained from the use of an animal model, may result in a better understanding of elderly hip fracture since the cortical shell is a significant contributor to the strength of the proximal femur. The objective of the present study was to determine if the greater trochanter's tendon insertions of the human, rat, and sheep differ in terms of morphology and mineralization. The tendons of the greater trochanter of the human, rat, and sheep were observed to insert via a fibrocartilage insertion. The mineral content of the human and sheep calcified fibrocartilage was significantly higher than that of the rat calcified fibrocartilage (P < 0.01). Additionally, the mineral content of the rat cortical bone was significantly higher than that of the human cortical bone (P < 0.01). The mineral content of the calcified fibrocartilage and bone of the human and sheep were not statistically different from each other. There were also more similarities between the bone structure and lacunae density of the human and sheep than between the human and the rat. This suggests that the tendon insertions of the sheep are a better model than the tendon insertions of the rat for the investigation of calcified fibrocartilage in elderly hip fractures.
authors.affiliation: Bone and Joint Research Laboratory, VA Salt Lake City Health Care System, 500 Foothill Drive, Salt Lake City, UT 84148, USA.
authors.forename: Jill E
authors.initials: JE
authors.lastname: Shea
authors.forename: Rhett K
authors.initials: RK
authors.lastname: Hallows
authors.forename: Roy D
authors.initials: RD
authors.lastname: Bloebaum
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015519:Bone Density; D002113:Calcification, Physiologic; D002358:Cartilage, Articular / Q000033:anatomy & histology* / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D005272:Femur Neck / Q000033:anatomy & histology* / Q000378:metabolism; D006620:Hip Fractures / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D051381:Rats; D012756:Sheep / Q000033:anatomy & histology*; D013710:Tendons / Q000033:anatomy & histology*