The vascular anatomy of the femoral head and neck has been previously reported, with the primary blood supply attributed to the deep branch of the Medial Femoral Circumflex Artery (MFCA). This understanding has led to development of improved techniques for surgical hip dislocation for multiple intra-capsular hip procedures including Hip Resurfacing Arthroplasty (HRA). However, there is a lack of information in the literature on quantitative analysis of the contributions of the Lateral Femoral Circumflex Artery (LFCA) to femoral head and neck. Additionally, there is a lack of detailed descriptions in the literature of the anatomic course of the LFCA from its origin to its terminal branches. Twelve fresh-frozen human pelvic cadaveric specimens were studied (mean age 54.3 years, range 28–69). One hip per specimen was randomly assigned as the experimental hip, with the contralateral used as a control. Bilateral vascular dissection was performed to cannulate the MFCA and LFCA. Specimens were assigned as either LFCA-experimental or MFCA-experimental. All specimens underwent a validated quantitative-MRI protocol: 2mm slice thickness with pre- and post- MRI contrast sequences (Gd-DTPA diluted with saline at 3:1). In the LFCA-experimental group 15ml of MRI contrast solution was injected into the LFCA cannula. In the MFCA-experimental group 15ml of contrast solution was injected into the MFCA cannula. On the control hip contrast solution was injected into both MFCA and LFCA cannulas, 15ml each (30ml total for the control hip). Following MRI, the MFCA and LFCA were injected with polyurethane compound mixed with barium sulfate (barium sulfate only present in either MFCA or LFCA on each hip). Once polymerization had occurred, hips underwent thin-slice CT scan to document the extra- and intra-capsular course of the LFCA and MFCA. Gross dissection was performed to visually assess all intra-capsular branches of both the MFCA and LFCA and assess for extravasation. Quantitative-MRI analysis was performed based on Region of Interest (ROI) assessment. Femoral heads were osteotomized at the level of the largest diameter proximal to the articular margin and perpendicular to the femoral neck, for placement of a 360° scale. Measurements using the 360° scale were recorded. For data processing, we used right-side equivalents and integrated our 360° data into the more commonly used imaginary clock face.Introduction
Materials & Methods
The incidence of DVT and need for thrombo-prophylaxis following isolated distal lower extremity fractures is unknown. The purpose of this study was to determine whether or not thrombo-prophylaxis with low molecular weight heparin was needed in this trauma population. A Multicentered Prospective Randomised Double Blind Placebo Controlled Trial was designed to define the incidence of DVT and need for thrombo-prophylaxis in this population. A sample size of two hundred and ninety-nine patients ensured a one tailed type one error of alpha = 0.05 and power of 80% as confirmed from previous studies. Males and female patients between the ages of eighteen and seventy-five years with isolated distal lower extremity fractures (excluding the foot) were eligible. All patients had surgery within forty-eight hours after injury. Patients excluded from the trial were polytrauma patients, those medically unfit for the operating room, patients with foot fractures, those receiving anticoagulation, inability to provide consent, platelets 200 umol /L. Randomization was carried out via computer generation to receive either placebo or Fragmin for fourteen days. At fourteen days, all patients underwent bilateral venograms interpreted by three independent radiologists. Equivocal venograms were interpreted by consensus. Routine follow-up was carried out for all patients at two, six, eight and twelve weeks. A total of two hundred and ninety-nine patients were enrolled in the study. One hundred thirty-six patients in the Fragmin group and one hundred and twentyfive in the placebo group completed the intervention. There were one hundred and twenty-five males and one hundred and thirty-six females in total. There was no statistically significant difference in DVT incidence between those patients treated with Fragmin or Placebo (p = 0.41). Gender, medical issues, pre-operative level of activity and body mass index had no effect on the incidence of DVT. The incidence of DVT in fragmin treated and placebo treated patients is 8.1% and 11.2%, respectively (p = 0.41). This study suggests that DVT thrombo-prophylaxis is not indicated in this patient population. To our knowledge, this is the first Randomised Controlled Trial utilizing venograms (gold standard) for DVT identification.
The incidence of deep-vein thrombosis and the need for thromboprophylaxis following isolated trauma below the knee is uncertain. We have investigated this with a prospective randomised double-blind controlled trial using low molecular weight heparin with saline injection as placebo in patients aged between 18 and 75 years who had sustained an isolated fracture below the knee which required operative fixation. All patients had surgery within 48 hours of injury and were randomised to receive either the placebo or low molecular weight heparin for 14 days, after which they underwent bilateral lower limb venography, interpreted by three independent radiologists. Further follow-up was undertaken at two, six, eight and 12 weeks. A total of 238 patients fulfilled all the inclusion criteria, with 127 in the low molecular weight heparin group and 111 in the placebo group, all of whom underwent bilateral venography. There was no statistically significant difference in the incidence of deep-vein thrombosis between those patients treated with low molecular weight heparin or the placebo (p = 0.22). The number of deep-vein thromboses in the two groups was 11 (8.7%) and 14 (12.6%), respectively. Age and the type of fracture were significantly associated with the rate of deep-vein thrombosis (p = 0.001 and p = 0.009, respectively) but gender, comorbidities and the body mass index were not. The overall incidence of deep-vein thrombosis in this series was 11%. There was no clinical or statistical significant reduction in the incidence of deep-vein thrombosis with the use of thromboprophylaxis. However, we accept that owing to a cessation of funding, recruitment to this trial had to be ended prior to establishing the necessary sample size. Our results cannot, therefore, categorically exclude the possibility that low molecular weight heparin treatment could be beneficial. We recommend a further multicentre trial be undertaken to resolve this matter.
