Smith G K, Hill C M, Gregor T P, Olson K
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA.
J Am Vet Med Assoc. 1998 May 15;212(10):1560-3.
To determine whether distraction index (DI), a measure of passive hip joint laxity, at 2 months of age was predictive of DI at 4 or 12 months of age in German Shepherd Dogs.
Prospective cohort study.
45 German Shepherd Dogs.
DI was measured at 2, 4, and 12 months of age. At the same times, a standard ventrodorsal radiographic projection of the pelvis with the hip joints extended was obtained and examined for evidence of degenerative joint disease (DJD). To facilitate radiographic positioning, dogs were sedated or anesthetized.
DI at 2 months of age was not significantly correlated with DI at 4 or 12 months of age. However, DI at 4 months of age was correlated with DI at 12 months of age. The proportion of dogs with DI > or = 0.3 at 12 months of age that had radiographic evidence of DJD by 12 months of age (13/22; 59%) was significantly greater than the proportion of dogs with DI < 0.3 at 12 months of age that had radiographic evidence of DJD by 12 months of age (1/9; 11%).
For German Shepherd Dogs, DI at 2 months of age was not sufficiently reliable to predict DI at 4 and 12 months of age; however, DI at 4 and 12 months of age were comparable. We recommend that, for German Shepherd Dogs, DI not be measured before 4 months of age and that particularly for breeding dogs, DI be remeasured after maturity to confirm DI obtained at earlier ages. Studies including other breeds of dogs should be done to determine the youngest reliable age to initiate hip joint screening.
确定德国牧羊犬2月龄时的被动髋关节松弛度测量指标——牵张指数（DI）是否可预测其4月龄或12月龄时的DI。
前瞻性队列研究。
45只德国牧羊犬。
在2月龄、4月龄和12月龄时测量DI。同时，获取髋关节伸展时骨盆的标准腹背位X线投影，并检查是否有退行性关节病（DJD）的迹象。为便于X线定位，对犬只进行镇静或麻醉。
2月龄时的DI与4月龄或12月龄时的DI无显著相关性。然而，4月龄时的DI与12月龄时的DI相关。12月龄时DI≥0.3且在12月龄时有DJD X线证据的犬只比例（13/22；59%）显著高于12月龄时DI<0.3且在12月龄时有DJD X线证据的犬只比例（1/9；11%）。
对于德国牧羊犬，2月龄时的DI不足以可靠地预测4月龄和12月龄时的DI；然而，4月龄和12月龄时的DI具有可比性。我们建议，对于德国牧羊犬，在4月龄前不要测量DI，特别是对于种犬，应在成熟后重新测量DI，以确认早期获得的DI。应开展包括其他犬种的研究，以确定开始髋关节筛查的最可靠最小年龄。
