Total hip arthroplasty is nowadays a common treatment for a large number of pathological cases regarding the hip joint and is considered as the most successful orthopedic operation. With the mean age of patients constantly decreasing and the more intense way of life, the need for versatile implant designs has arisen. Currently modular hip implant systems are used extensively in order to compensate for difficult occasions, where offset and version correction are required. In addition to this femoral heads of bigger diameter have been introduced to deal with issues such as dislocation and impingement, although their influence on the mechanical behavior on the bone – implant assembly is not widely documented. Towards this direction a finite element model was generated. Computed tomographies of a cadaveric femur were used as raw data and processed, a Profemur-E system with variable heads was digitized, thus leading to a complete assembly consisting of the femur, the stem, the necks and the femoral heads in the commercial CAD software Solidworks. For typical loading scenarios – the stance phase of the gait cycle – the finite element analysis was performed in ANSYS Workbench. The results showed that the implementation of BFH and the neck version produced an increase in strains and stresses with respect to a normal head of 28mm and a straight neck in areas of clinical interest such as the calcar, the greater trochanter area and the stem tip region, considered responsible for thigh pain.

Total Hip Arthroplasty (THA) is one of the most important procedures in the fields of Reconstructive Orthopaedics. This study aims to present the preliminary results of the clinical and radiological evaluation of patients who have undergone THA with metal bearings, modular necks and big femoral heads and to correlate them with the results of the Finite Element Analysis. In the period from 1/1/2006 until today 90 patients (33 men and 57 women) with mean age 62,4 years have undergone primary THA. The patients were clinically and radiographically evaluated preoperatively, as well as postoperatively, in regular time intervals (1st, 3rd, 6th, 12th month and every year afterwards). The clinical assessment was based on two scales, Harris Hip Score (HHS) and Merle d’ Aubigne (MDA) score, whereas the radiographic on Engh criteria. The mean follow up was 16 months. The mean preoperative HHS and MDA score were 45 and 10,3 respectively, whereas 89 and 16,74 at the last evaluation. The mean Engh score was 16,12. No incidence of dislocation, infection and cup or stem adverse effect occurred. We demonstrate extensively, with respect to the used combination of neck and femoral head, the radiographic findings in the zones of Grün and Charnley, in the areas of the tip of the stem and the calcar, as well as the resulting clinical manifestations. The early clinical and radiological data are in line with the increase in the stresses and strains on the upper part of the femur, which are revealed through the Finite Element Analysis.

Introduction: TKA is usually performed under general or spinal anaesthesia (SA). Most of the patients who undergo this procedure are old and their postoperative rehabilitation could be compromised due to the adverse effects of the relevant anaesthesia. Lumbar Plexus and Sciatic nerve Block (LPSB) have been increasingly applied for intraoperative and postoperative analgesia. The aim of this study is to compare the time required for the performance of the anaesthesia technique, the quality of intraoperative anaesthesia and postoperative analgesia, the incidence of intraoperative or postoperative complications, the blood loss at the recovery room and the required intraoperative intravenous (IV) administration of fluid volume.

Material & Methods: Fifty (50) patients, mean age 70± 5years, ASA I-III were randomly divided into two groups to receive spinal anaesthesia (group A) or LPSB (group B). Patients in group A (n=25) received hyperbaric Bupi-vacaine 0.5% plus 15mcq Fentanyl through atraumatic 25g needle. Lumbar plexus and sciatic nerve block were performed with a 15cm insulated needle (Brown) and nerves were identified by a peripheral electric nerve stimulator. 30 and 15 ml of Ropivacaine (0.5%) were used for each block respectively. All patients received 0.2mg/ Kg of Midazolam and 50μg of Fentanyl IV. The success of the technique was defined as a complete sensory and motor block. All patients received postoperatively Patient-Controlled Anaesthesia (PCA) with morphine intravenously. Time to perform blockade, sensory and complete motor block, hemodynamic parameters, blood loss, IV fluid volume, postoperative analgesic requirements and satisfaction score were recorded. Results were analyzed with Chi Square test and Student’s t-test (level of significance: p< 0.05).

Results: Demographic data, operating time and hemo-dynamic parameters were similar in both groups. Three patients (group B) had insufficient blocks and were converted to general anaesthesia. Although SA is performed and accomplishes complete motor and sensory blockade faster (p< 0,05), LPSB leaded to decreased necessity of intraoperative fluid loading and blood loss at the recovery room (p< 0,05). Overall patient’s satisfaction till leaving the recovery room, Visual Analogue Score (VAS) intraoperatively, 4 and 8hours postoperatively and analgesic counts (recorded through the PCA) in the first 24hours were statistically significant between two groups, in favor of patients with LPSB.

Conclusion: PLSB is an effective alternative to spinal anesthesia taking into account basic clinical and anaesthesiological parameters intraoperatively and immediate postoperatively. Concerning postoperative pain and required administration of analgesics during the first 24hours, LPSB is more efficient compared to SA, underlining the importance of overall patient’s satisfaction during the first postoperative day.