Troy Karen L, Lundberg Hannah J, Conzemius Michael G, Brown Thomas D
Department of Orthopaedics and Rehabilitation, University of Iowa, 52242, USA.
Iowa Orthop J. 2007;27:17-23.
Orthopaedic management of femoral head osteonecrosis remains problematic, partly because of inability to systematically compare treatments in an animal model whose natural history parallels the human in terms of progression to femoral head collapse. Recently, it was determined that collapse could be consistently achieved for cryogenically induced osteonecrosis in the emu. Toward delineating the comparative hip joint biomechanics of emus versus humans, for purposes of establishing the emu as a model for human femoral head osteonecrosis, habitual hip joint activity level was quantified for a group of seven healthy adult emus housed in an outdoor research pen typical of those used in emu farming operations. The daily number of steps taken, and the time spent with the hips loaded (standing, or squatting/sitting) versus unloaded (recumbent), were quantified from 24-hour videotape recordings, analyzed by four independent observers. The average number of steps taken per day was 9563, which extrapolates to 1.8 million hip loadings per year, a value that falls in the same general range as seen in normal adult humans. On average, the emus spent 4:05 hours per day idly standing, 2:12 hours squatting/sitting, and 10:44 hours recumbent; they underwent an average of 37 transitions per day between the respective posture/activity states.
股骨头坏死的骨科治疗仍然存在问题，部分原因是无法在自然病程与人类股骨头塌陷进展相似的动物模型中系统地比较各种治疗方法。最近，人们发现鸸鹋经低温诱导的骨坏死能够持续出现塌陷。为了确定鸸鹋与人类髋关节生物力学的差异，以便将鸸鹋确立为人类股骨头坏死的模型，对一组饲养在户外研究围栏中的7只健康成年鸸鹋的习惯性髋关节活动水平进行了量化，这种围栏是鸸鹋养殖中常用的典型围栏。通过4名独立观察者对24小时录像记录进行分析，量化了鸸鹋每天行走的步数，以及髋关节负重（站立、蹲坐/坐下）与不负重（卧躺）的时间。鸸鹋每天平均行走步数为9563步，据此推算每年髋关节负重达180万次，这一数值与正常成年人类的范围相同。鸸鹋平均每天有4小时05分钟的时间在闲散站立，2小时12分钟在蹲坐/坐下，10小时44分钟在卧躺；它们每天在不同姿势/活动状态之间平均转换37次。
