Biomechanical and histological analyses of the fracture healing process after direct or prolonged reduction.

BACKGROUND: Reduction of femoral shaft fractures remains a challenging problem in orthopaedic surgery. Robot-assisted reduction might ease reduction and fracture treatment. However, the influence of different reduction pathways on patients' physiology is not fully known yet. Therefore, the aim of this study was to examine the biomechanics and histology of fracture healing after direct and prolonged robot-assisted reduction in an in vivo rat model. METHODS: 144 male CD® rats were randomly assigned to 12 groups. Each animal received an external fixator and an osteotomy on the left femoral shaft. On the fourth postoperative day, the 1× reduction groups received a single reduction maneuver, whereas the 10× reduction groups received the same reduction pathway with ten repetitions. The control groups did not undergo any reduction maneuvers. Animals were killed after 1, 2, 3 and 4 weeks, respectively, and the composition of the fracture gap was analyzed by µCT and non-decalcified histology. Biomechanical properties were investigated by a three-point bending test, and the bone turnover markers PINP, bCTx, OPG, sRANKL, TRACP-5b, BALP, and OT/BGP were measured. RESULTS: One week after the reduction maneuver, µCT analysis showed a higher cortical bone volume in the 1× reduction group compared to the 10× reduction group. Biomechanically, the control group showed higher maximum force values measured by three-point bending test compared to both reduction groups. Furthermore, less collagen I formation was examined in the 10× reduction group compared to the control group after 1 week of fracture healing. PINP concentration was decreased in 10× reduction group after 1 week compared to control group. The same trend was seen after 3 weeks. CONCLUSION: A single reduction maneuver has a beneficial effect in the early phase of the fracture healing process compared to repeated reduction maneuvers. In the later phase of fracture healing, no differences were found between the groups.

IgG4-related sclerosing cholangitis mimicking hilar cholangiocarcinoma (Klatskin tumor): a case report of a challenging disease and review of the literature.

BACKGROUND: Even though IgG4-related disease has gained increased attention worldwide, the diagnosis remains challenging. IgG4-related sclerosing cholangitis (IgG4-SC) is not well described in the western hemisphere and may mimic cholangiocarcinoma (CC), especially when occurring without other symptoms such as, e.g. concurrent pancreatitis or retroperitoneal fibrosis. We present a case to add further information to the diagnosis and treatment of this challenging disease. CASE REPORT: A 60-year-old male patient presented with painless jaundice. Prior medical history showed diabetes mellitus type I, high blood pressure, and deep vein thrombosis. Diagnostic investigations were strongly suspicious of a Klatskin tumor, although biopsies were inconclusive. The tumor marker Carbohydrate Antigen 19-9 (CA 19-9) was elevated. Prior to the recommended surgery, the patient had two second opinions in two different university hospitals, both arguing for surgery as well. The patient received hilar resection with right hemihepatectomy. During the postoperative course, some major complications occurred, i.e. recurrent pleural effusion, abscess in the liver resection area, sepsis, ileus, and restricted liver metabolism. Treatment with prednisolone did not show any improvement. Approximately 3 months after surgery, the patient died in consequence of acute respiratory failure. Histology showed no signs of CC, but IgG4-SC could be diagnosed. CONCLUSION: In the case of preoperative signs of CC, differential diagnosis of IgG4-SC needs to be considered, in particular, in cases with missing histologic proof of malignant disease.