Clinical orthopaedics and related research
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Clin. Orthop. Relat. Res. · Aug 1993
Clinically inapparent hypoxemia after skeletal injury. The use of the pulse oximeter as a screening method.
The efficacy of the pulse oximeter was evaluated in lieu of multiple arterial blood gas (ABG) determinations as a screening method for the early diagnosis of hypoxemia and clinical fat embolism syndrome. A prospective analysis was performed on 43 patients with long bone and pelvic fractures without any associated chest wall, head, or intraabdominal trauma. A standard pulse oximetry reading was obtained initially within 12 hours of injury and at 24-hour intervals thereafter until the patient had been observed for 72 hours. ⋯ These patients were subsequently managed with an intensive pulmonary care regimen. Hypoxemia resolved in all patients within 48 hours of the initiation of treatment. The pulse oximeter is an efficient and reliable screening device to identify patients with clinically unrecognized hypoxemia.
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Clin. Orthop. Relat. Res. · Aug 1993
Bone-healing patterns affected by loading, fracture fragment stability, fracture type, and fracture site compression.
The major factors determining the mechanical milieu of a healing fracture are the rigidity of the selected fixation device, the fracture configuration, the accuracy of fracture reduction, and the amount and type of stresses occurring at the bone ends dictated by functional activity and loading at the fracture gap. Of the effects of these factors on fracture healing and remodeling in the canine tibia under unilateral external fixation, the two most significant factors in promoting periosteal callus formation were the amount of physiologic loading as dictated by the body weight and the presence of a significant fracture gap. Uniform axial loading and motion, performed at two or four weeks, did not increase callus formation but did reduce the existing fracture gap. ⋯ Intracortical new bone formation and porosity were related to the healing pattern and not to the loading magnitude. Endosteal new bone formation showed a strong correlation with the presence of a fracture gap. In terms of torsional strength and energy absorption at failure, the fractures healing through a combination of primary and secondary bone union mechanisms showed the mechanical strength of the healing bone closest to intact bone.