Kanji Asada

Prostaglandin E1 as a hypotensive drug during general anesthesia for total hip replacement

STUDY OBJECTIVE To determine the effect of intravenous administration of prostaglandin E1 (PGE1) in inducing controlled hypotension during general anesthesia. DESIGN Randomized, prospective study. SETTING Inpatient surgery at a university hospital. PATIENTS 57 ASA physical status I and II patients scheduled for total hip replacement. INTERVENTIONS In 29 patients undergoing total hip replacement, PGE1 (0.11 +/- 0.03 micrograms/kg/min) was infused to induce hypotension during general anesthesia with enflurane, isoflurane, or sevoflurane in nitrous oxide and oxygen. In another 28 patients, the control group, normotensive anesthesia was performed for the same procedure. MEASUREMENTS AND MAIN RESULTS Systolic blood pressure decreased significantly (p < 0.01) from 136 +/- 22 mmHg to 93 +/- 10 mmHg during PGE1 infusion, although heart rate did not change significantly. Arterial hemoglobin oxygen saturation showed a mild but significant decrease (p < 0.05) during PGE1 infusion. Blood loss (480 +/- 132 ml) and blood transfusion (280 +/- 260 ml) during surgery were significantly less in patients with hypotensive anesthesia (p < 0.01 and p < 0.05, respectively) than in patients with normotensive anesthesia (667 +/- 326 ml and 468 +/- 395 ml, respectively). Blood loss and blood transfusion after surgery were similar in both groups. In the recovery room or surgical ward, 3 of 29 patients with hypotensive anesthesia needed rapid blood transfusion because of moderate hypotension. The volume of urine during surgery was significantly less (p < 0.05) in the control group. Two patients developed mild phlebitis at the site of the PGE1 infusion, but there were no serious side effects. CONCLUSION These data suggest that PGE1 can be used safely to induce hypotension, thereby reducing blood loss during total hip replacement with general anesthesia.

Intraoperative Evaluation of Component Stability in Total Knee Arthroplasty

Information concerning component stability immediately following total knee arthroplasty (TKA) must be reliable. To this end, we developed a measurement system for tibial component, which is thought to be the most frequent loosening component, using three non-contact displacement transducers fixed on the tibial cortex. The measurement system consists of three parts: A device which is connected to the tibial component and has three steel plates, a sensor unit, and an external fixator which connects the sensor unit to the tibial shaft. A load is applied with a push-pull gauge from which a voltage output is supplied to the A–D converter. Sampled data are calculated as displacements by a personal computer that displays the tibial component micromotion data on a cathode ray tube (CRT).

Histological Study of Acetabular Clear Zone after Acetabular Reaming for Hip Arthoplasty using an Alumina Ceramic Endoprosthesis and a Metal One

ABSTRACT We have performed reconstruction of the hip following osteoarthritis by alumina ceramic bipolar hip prosthesis. We placed specially prepared alumina ceramic and metal heads in the femur to contact the acetabulum of beagle dogs, after the articular cartilage had been removed completely by reaming and bone marrow exposed. Radiographically, one month after the surgery, a well defined clear zone appearsed between acetabulum and prosthetic head, and three months following the surgery, the reamed acetabulum was completely reshaped and the clear zone became more apparent. In the clear zone, histological study showed changes from granulation tissue at early stage to matured fibrous connective tissue both in alumina ceramic and metal heads, and showed absorption and osteogenic response of the trabeculae in the bone marrow. The metal head formed loose connective tissue with many gaps whereas the ceramic one produced close stable tissue one year after surgery. The ceramic head was better finished for roundness and surface roughness than the metal one and was no changes at periods at 1 and 6 months post operation. Therefore we concluded the alumina ceramic was better material for an endoprosthetic head than Cr-Co-Mo alloy.