Background: In kinematically aligned total knee arthroplasty (KA-TKA), the cylindrical axis (CA) is very important in restoring the native joint line and kinematics of the pre-arthritic knee. This study aimed to determine the accuracy of patient-specific instrument (PSI) for restoring the CA for femoral bone resection in KA-TKA. Methods: Thirty KA-TKAs were performed using a computed tomography (CT)-based PSI system. Data from preoperative CT were reconstructed into three-dimensional (3D) models using 3D-planning software. The CA was created by connecting the centers of each virtual sphere to the medial and lateral femoral condyles using computer software. Femoral bone resection of the distal and posterior condyles was performed parallel to the sagittal planes of the CA. The thickness of the CA-referenced bone resection was determined based on the thickness necessary for the respective regions of the femoral component. The PSI was manufactured to locate the guide pin for a conventional cutting block. The accuracy of PSI for KA-TKA was evaluated as the absolute error between the preoperatively predicted thickness and the intraoperative measurements in each of the four regions, as well as the difference in error between distal-medial (DM) and posterior-medial (PM) and between distal-lateral (DL) and posterior-lateral (PL). Results: The differences in thickness of bone cut in the DM, DL, PM, and PL were 0.79 ± 0.39 mm (range, –1.20 to 1.50), 0.70 ± 0.42 mm (range, –1.50 to 1.50), 0.80 ± 0.46 mm (range, –0.80 to 1.50), and 0.75 ± 0.47 mm (range, –2.10 to 1.40), respectively. There was no significant difference in the thickness error between DM and PM (p = 0.959) and between DL and PL (p = 0.812). Conclusions In KA-TKA, PSI was effective for accurate femoral bone resection based on virtually planned thickness.

BACKGROUND: Acute renal failure is one of the leading causes of postoperative morbidity and mortality. The purpose of this study was to determine the risk factors that are associated with acute renal failure after colorectal surgery. MATERIALS AND METHODS: Five hundred seventy patients who operated colorectal surgery at the Yeungnam University Medical Center over three years from 2004 to 2006 were enrolled in this study. The effects of gender, age, ASA classification, concomitant disease, surgery type and duration, reoperation, urogenital manipulation, medication, hypotension, hypovolemia, transfusion, and postoperative ventilatory care on the occurrence of acute renal failure after colorectal surgery were studied. RESULTS: The major risk factors of acute renal failure after colorectal surgery were age of patients (P=0.003), ASA classification (P<0.001), concomitant disease (P<0.001), duration of the time surgery (P=0.034), reoperation (P=0.001), use of intraoperative diuretics (P=0.005), use of postoperative diuretics (P<0.001), intraoperative hypotension (P=0.018), intraoperative transfusion (P<0.001), postoperative transfusion (P<0.001), and postoperative ventilatory care (P=0.001). CONCLUSION: Multiple factors cause synergistic effects on the development of acute renal failure after colorectal surgery. Therefore, efforts to reduce the risk factors associated with acute renal failure are needed. In addition, intensive postoperative care should be provided to all patients.
Academic Medical Centers ; Acute Kidney Injury* ; Classification ; Colorectal Surgery* ; Diuretics ; Humans ; Hypotension ; Hypovolemia ; Mortality ; Postoperative Care ; Reoperation ; Risk Factors*