A highly accurate and reproducible method for determining the orientation of the acetabulum's aperture will benefit both surgeons and patients, by further refining the distinctions between normal and abnormal hip characteristics. Enhanced understanding of the acetabulum could be useful in the diagnostic, planning, and execution stages for surgical procedures of the hip or in advancing the design of new implant systems.

» Appropriate total hip arthroplasty (THA) reconstruction must simultaneously address component position, restoration of biomechanics, and soft-tissue balance.» Preoperative planning for complex THA cases should include radiographic templating, a detailed case plan that contains backup implant options, and a thorough understanding of the patient’s preoperative examination.» Using a systematic approach to soft-tissue balancing in THA enhances the ability to intraoperatively execute the preoperative plan.» In patients with preexisting deformities (e.g., dysplasia or prior surgery), increased attention to abductor function is necessary when assessing acetabular component placement and offset.

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Introduction: The oxidation/reduction (redox) chemistry of blood during resuscitation is not well defined. Improved understanding of whole blood redox behavior would assist in developing better resuscitation monitoring and possibly reducing free radical injury both of which are PULSE initiative priorities. We use direct electrochemical measurement of equilibrium redox potential to assess the hypothesis that the overall response of blood to strong oxidant/reductant challenge is altered during shock. Methods: Five swine underwent hemorrhage to an oxygen debt (OD) of 80 cc/kg. Arterial blood was tested at baseline (BL) and after hemorrhage when OD equaled 40 and 80 cc/kg. Native redox potential was measured as the equilibrium voltage potential recorded between a freshly polished 2mm Au and standard Ag/AgCl electrode submerged in whole blood (n=34). The oxidative and reductive stress responses at each level of OD were defined as the change from native voltage potential induced by the addition of a strong oxidant (KMnO4) (n=18) or reductant (Dithiotreitol) (n=18). Mean native redox potentials and mean redox stress responses were compared for differences at increasing levels of OD using repeated measures ANCOVA. Results: Lactate increased significantly with OD (mean diff BL vs. OD=80, +4.7 mmol/L [1.3, 8.1]). No effect of OD was found on native redox potential (p value =0.233). A significant effect of OD was found on redox stress response (p value =0.0276). The redox response to oxidative stress increased from BL with increasing oxygen debt, and became significantly greater at OD=80 cc/kg (mean diff =+31.9 Rmv [3.9, 59.9]). Conclusions: Whole-blood redox potential did not change significantly even with severe shock, suggesting active redox buffering. However, our results suggest that the oxidative buffering capacity of blood may become impaired during severe shock as demonstrated by the significantly more positive redox potentials elicited by oxidative stress when OD was elevated. Impaired redox buffering during shock may exacerbate free radical injury induced by the oxidative stress of resuscitation. Monitoring the response of blood to oxidative stress may be a useful way to determine susceptibility to oxidative damage during resuscitation.