Background: There are many studies that analyze ischemia-reperfusion injury in different organs (brain, heart...) but they are very scarce in skeletal muscle. The few studies performed in humans show partial results, and none include morphological, inflammatory, biochemical, metabolic and hemodynamic alterations. The objective of our study was to typify ischemic and ischemia-reperfusion injury in skeletal muscle in patients undergoing total knee arthroplasty from several points of view: morphological, biochemical, metabolic and hemodynamical, as well as to evaluate the protective effect of a single-dose of corticoids on the above-mentioned parameters.
Methods: Forty-one patients participated in the study. They were randomly assigned to either group A: no corticoid administered; or to group B: a single dose of methylprednisolone was administered before performing ischemia. Blood samples were drawn at different intervals for determination of inflammatory biomarkers and necrosis enzymes, and three muscle biopsies were performed for histological studies.
Results: The ischemia period ranged from 50 to 84 minutes in both groups. There were no histological differences either between the groups. We found significant differences in inflammatory markers: there was a higher increase in C-reactive protein, erythrocyte sedimentation rate and Interleukin-6 in group A, while the leukocyte count was higher in group B. \
Conclusions: Human skeletal muscle can bear periods of ischemia followed by reperfusion as far as 1.5 h without showing any sign of structural, ultrastructural or inmunoshistochemical damage. We have described the biochemical changes that take place in patients submitted to total knee arthroplasty with tourniquet under spinal anesthesia during the first 48 h post-procedure. Adding a single dose of methylprednisolone 7 mg/kg IV immediately prior to surgery significantly reduced the levels of some markers of morbidity.