Uhthoff H K, Jaworski Z F
Clin Orthop Relat Res. 1985 Oct(199):284-91.
An external callus is always associated with so-called stress fractures, but a fracture line cannot always be demonstrated by radiologic means. In such instances it is assumed that an undisplaced fracture or microfracture must nevertheless exist for an external callus to form. In this experimental study, 18 beagles were immobilized in a shoulder spica for periods of time ranging from 6 to 32 weeks and then remobilized. At the time of sacrifice, which varied from four to 28 weeks after remobilization was started, eight showed on radiographs an external fusiform bone formation on the distal metacarpal metaphysis during the remobilization period without evidence of a fracture line. Serial histologic examination, in seven metacarpi, also failed to reveal the presence of any break in the bone's continuity. Although this does not exclude the accumulation of microdamage (mechanical fatigue) at such sites, there is sufficient evidence that the circumscribed periosteal reaction occurred at a site of increased stress in the absence of an actual fracture. Consequently, this condition is called a periosteal stress-induced reaction.
骨外骨痂总是与所谓的应力性骨折相关联，但骨折线并非总能通过放射学手段显示出来。在这种情况下，人们认为，尽管没有移位的骨折或微骨折，但必须存在才能形成骨外骨痂。在这项实验研究中，18只比格犬被固定在肩人字石膏中6至32周不等，然后再活动。在开始再活动后4至28周处死时，8只犬在再活动期间的X线片上显示掌骨远端干骺端有梭形骨形成，无骨折线证据。对7个掌骨进行的系列组织学检查也未发现骨连续性有任何中断。虽然这并不排除在这些部位累积微损伤（机械疲劳），但有充分证据表明，在没有实际骨折的情况下，局限性骨膜反应发生在应力增加的部位。因此，这种情况被称为骨膜应力性诱导反应。
