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Objectives: The study was aimed at the assessment of specifi c complications depending on the sliding hip screw position. Background: The fi nite element method in the biomechanical analysis of this implant may be used to predict the mechanical failure due to the screw position. Methods: 380 sliding screw osteosyntheses for stable pertrochanteric fractures of 365 patients were included in the study. We divided and analysed the osteosyntheses with fi ve various screw positions and focused on the specifi c complications development. For the construction of the fi nite element model of the femur, the program ABAQUS 6.9 was used. Analyses were performed with evaluation of the bone response to the different screw locations (strain and stress) with maximum low-cycle high stress loading. Results: The specifi c complication rate was 10 %, with the re-operation rate of 4.2 %. If placing the screw in the middle third of the neck it reduced signifi cantly strain patterns of the plate and screw. A screw position in the superior third of the neck signifi cantly increased the strain of the plate and screw by more than 63 %. Conclusions: The conformity in the clinical and biomechanical analyses was observed. The fi nite element model can be considered as valid in predicting sliding screw failures (Tab. 4, Fig. 8, Ref. 30).

PURPOSE OF THE STUDYEvaluation of infectious complications in patients with proximal femoral fractures treated by osteosynthesis using dynamic hip screws (DHS). MATERIALThe group included 501 patients with 532 DHS procedures performed in the years 1996-2010. In 31 patients osteosynthesis was carried out bilaterally. METHODSOsteosynthesis was indicated for femoral neck fracture in 18 hips and for pertrochanteric fracture in 514 hips. Prophylactic antibiotic therapy was administered within 48 hours of surgery. The occurrence of infectious complications (surface and deep wound infection), presence of infectious agents, risk factors, and the course of treatment and its outcome were investigated. RESULTSOf 532 fractures treated by DHS osteosynthesis, seven were infected (1.3%) as follows: one fracture of the femoral neck with methicillin-resistant Staphylococcus aureus, and, of six pertrochanteric fractures, four with Staphylococcus aureus, one with Escherichia coli and one with Staphylococcus epidermidis. Surface wound infection was diagnosed in one case (0.2%) and deep infection in six cases (1.1%). Five revision DHS procedures were carried out in five patients. One or more risk factors were found in each patient with infected DHS. The treatment of infection included wound dressing and abscess drainage without reoperation in two cases, implant removal in three, and implant removal with femoral head resection and spacer insertion in two cases. Second-stage total hip arthroplasty (THA) was performed in one case. Of the seven infected fractures, five (71%) healed successfully. DISCUSSIOnDHS osteosynthesis is a reliable method for treating proximal femoral fractures. The 1.3% infection rate in our group is comparable with other relevant studies. This complication is serious and requires prolonged treatment but is not as devastating as an infected THA. For the treatment of infected DHS osteosynthesis, standard methods from screw removal to second-stage THA were employed. COnCLUSIOnSInfectious complications following osteosynthesis with dynamic hip screws are rare events in the treatment of proximal femoral fractures. Staphylococcus aureus was the most frequently isolated infectious agent. Each infectious complacation was associated with one or more risk factors. Antibiotic prophylaxis is important particularly in patients at risk.

PURPOSE OF THE STUDYTo present the results of primary total hip arthroplasty (THA) with use of the hemispheric threaded Ultima cup at 8.5-year follow-up. MATERIALBetween 1996 and 1999, a total of 40 Ultima acetabular components were used in 33 patients (15 men and 18 women). The average age at the time of surgery was 61.2 years (range, 45 to 71). By the end of 2006, 36 cups were assessed. Indications for the primary THA procedure included primary arthritis in 32 hips, post-traumatic arthritis in three, post-dysplastic arthritis in two, femoral neck fracture in two and rheumatoid arthritis in one. METHODSThe average follow-up was 8.5 years (range, 7 to 10). The indication criteria for primary implantation were evaluated, i.e., body mass index, patients' activity and their age. THA outcome was evaluated on the basis of clinical rating (Harris hip score) and pain assessment and on radiographic findings on which the acetabulum before and cup position after THA were compared, and potential changes in cup position, acetabular cup loosening or para-articular ossifications were observed. RESULTSGood outcomes were found in 88.9 % of the hips. In most, cup position was satisfactory. One acetabular component was implanted in a varus position (34°). An intraoperative complication included fracture of the greater trochanter, which was left untreated for spontaneous healing.The early-postoperative complications were one dislocation, two wounds with serous secretion not requiring revision surgery, and one large haematoma. Stem fracture as a late complication was recorded in two THAs. Radiolucencies were found in six hips and paraarticular ossifications in four. Migration of the cup with protrusion into the acetbulum occured in one patient 3 years after THA. Four cups showed aseptic loosening within 3 to 7 years of surgery. No infection was recorded in this THA group. DISCUSSIONInformation on mid-and long-term outcomes of the use of cementless acetabular cups in the relevant literature is sparse. The Ultima cup is dealt with only in the report by Pazdírek et al., whose results are in agreement with ours, but involve a lower number of implanted cups and a shorter follow-up. In this study, loosening was recorded only in cups larger than 32 mm in diameter. In comparison with our group of cementless BMT acetabular components, the use of cementless Ultima cups gives better results at mid-term follow-up. CONCLUSIONSAt 8.5-year follow-up, 88.9 % of the Ultima acetabular components were without radiographic signs of loosening. Attention should be paid primarily to THA patients with a thin wall acetabulum requiring a larger cup and a 32-mm liner.

PURPOSE OF THE STUDYTo present the results of Dynamic Hip Screw (DHS) osteosynthesis for the treatment of proximal femoral fractures with a focus on specific complications of this method. MATERIALFrom 1997 till 2007, the authors performed 367 DHS osteosyntheses to treat 341 patients with fractures of the proximal femur. The average patient age was 81.8 years (21-101). Twenty-six patients had surgery for bilateral fractures. METHODSOsteosynthesis was always carried out using a 135° DHS (Medin, Nové Město na Moravě, Czech Republic) to manage fractures of the femoral neck (13 ); trochanteric and basicervical fractures (349 ) and subtrochanteric fractures (5). At the end of 2009 the group was evaluated in terms of specific complications, i.e., intra-operative, early and late post-operative complications, and reoperation incidence. Hip radiographs were made before the patient was discharged, at 6 weeks, then at 3, 6 and 12 months post-operatively.When there were no complications, X-ray examination was repeated every 12 months. RESULTSA total of 39 specific complications of the DHS system (11 %) were recorded. The 17 intra-operative complications included: insufficient reduction (10), broken tip of a K-wire (3), faulty technical procedure (2) and fracture of the distal fragment during surgery (2). In addition, 22 post-operative complications (both early and late) were recorded: "cut-out" phenomenon (6), avascular necrosis of the femoral head (5), progression of coxarthrosis (4), screw breakage (2) , femoral fracture under the plate (2), pseudoarthrosis (2) and late infection (1).Complications in relation to the fracture site were as follows: femoral neck fractures, 3/13 (23 %) all requiring revision surgery; trochanteric fractures, 35/349 (10 %), of these 12 reoperated; subtrochanteric factures, 1/5 (20 %) no revision surgery required. Of the 367 fractures treated by DHS osteosynthesis, 15 (4 %) required revision surgery for specific complications. The mortality rate within one year of surgery was 49 %. DISCUSSIONEnough information on treatment options for proximal femoral fractures can be found in the literature. However, less attention is paid to their complications. The authors used DHS osteosynthesis to treat 367 fractures during 11 years, and recorded 11 % of complications. These can be prevented by the correct indication (the final decision of the implant to be used is sometimes made only after a fracture reduction under an X-ray image intensifier on the operating theatre), correctly performed procedure and thorough post-operative care. The high one-year mortality was due to the high average age in the group. CONCLUSIONSThe authors regard DHS as an effective method to treat stable pertrochanteric fractures and fractures of the femoral neck in younger patients. Complications most often occur as a result of technical mistakes made by surgeons.