Optimizing perioperative analgesia for patients undergoing operative fixation of hip fractures

This PhD thesis describes work carried out on investigation of various interventions with the aim to optimise the anaesthetic management of patients scheduled to undergo operative fixation of hip fractures. We analysed the perioperative effects of continuous femoral nerve block, single preoperative dose of i.v. dexamethasone, the intention to deposit local anaesthetic in different locations around the femoral nerve during ultrasound guided femoral nerve block, continuous spinal anaesthesia and peri-surgical site infiltration with local anaesthetic after surgical fixation of hip fractures. Continuous femoral nerve block provided more effective preoperative analgesia six hours after the insertion of the perineural catheter compared to a standard opiate-based regimen in patients undergoing operative fixation of fractured hip. A single low dose of preoperative dexamethasone in the intervention group decreased pain scores by 75% six hours after the surgery. Both interventions had no major effect on the functional recovery in the first year after the surgical fixation of fractured hip. The results of the ultrasound guided femoral nerve block trial showed no clinical advantage of intending to deposit local anaesthetic circumferentially during performing femoral nerve block. Using the Dixon and Massey’s “up- and-down” method, we demonstrated that intrathecal 0.26 ml of 0.5% bupivacaine provided adequate surgical anaesthesia within 15 minutes in 50% of patients undergoing operative fixation of hip fracture. Finally, we demonstrated that local anaesthetic infiltration had no effect on pain scores 12 hours after the surgical fixation of fractured neck of femur. In addition to this original body of work, a review article was published on femoral nerve block highlighting the use of ultrasound guidance. In conclusion, the results of this thesis offer an insight into interventions aimed at optimising perioperative analgesia in patients scheduled to undergo operative fixation of hip fractures.

Role of the fibula in the stability of diaphyseal tibial fractures fixed by intramedullary nailing

Background: For tibial fractures, the decision to fix a concomitant fibular fracture is undertaken on a case-by-case basis. To aid in this clinical decision-making process, we investigated whether loss of integrity of the fibula significantly destabilises midshaft tibial fractures, whether fixation of the fibula restores stability to the tibia, and whether removal of the fibula and interosseous membrane for expediency in biomechanical testing significantly influences tibial interfragmentary mechanics. Methods: Tibia/fibula pairs were harvested from six cadaveric donors with the interosseous membrane intact. A tibial osteotomy fracture was fixed by reamed intramedullary (IM) nailing. Axial, torsion, bending, and shear tests were completed for four models of fibular involvement: intact fibula, osteotomy fracture, fibular plating, and resected fibula and interosseous membrane. Findings: Overall construct stiffness decreased slightly with fibular osteotomy compared to intact bone, but this change was not statistically significant. Under low loads, the influence of the fibula on construct stability was only statistically significant in torsion (large effect size). Fibular plating stiffened the construct slightly, but this change was not statistically significant compared to the fibular osteotomy case. Complete resection of the fibula and interosseous membrane significantly decreased construct torsional stiffness only (large effect size). Interpretation: These results suggest that fixation of the fibula may not contribute significantly to the stability of diaphyseal tibial fractures and should not be undertaken unless otherwise clinically indicated. For testing purposes, load-sharing through the interosseous membrane contributes significantly to overall construct mechanics, especially in torsion, and we recommend preservation of these structures when possible.