Venous thromboembolism after lower limb arthroplasty: is chemical prophylaxis still needed?

BACKGROUND: Venous thromboembolism (VTE) is a significant complication of lower limb arthroplasty. The National Institute for Health and Care Excellence recommends routine use of chemical and mechanical prophylaxis to prevent VTE. Our high-volume, elective, arthroplasty unit adopted this guidance in 2008. PURPOSE: We examined our incidence of VTE before and after introduction of chemical thromboprophylaxis to determine whether the incidence of VTE reduced. METHODS: We retrospectively gathered data on 2 cohorts of patients-from January 2004 to August 2007 (Group 1) and January 2010 to December 2012 (Group 2). Patients in Group 1 received mechanical prophylaxis only (unless particularly high risk for VTE), and patients in Group 2 received mechanical and chemical prophylaxis. We recorded VTE occurring within 6 months of surgery. Patients in Group 1 receiving chemical prophylaxis were excluded. RESULTS: Group 1 had 2320 cases of primary and revision lower limb arthroplasty, and Group 2 had 1430 cases. VTE occurred in 37 cases in Group 1 (1.6 %), and in 17 cases in Group 2 (1.2 %). This difference was not statistically significant (p = 0.26). In Group 1, 1 patient died within 6 months due to pulmonary embolism (0.04 %); there were no VTE-related deaths in Group 2 (0 %). This was also not statistically significant (p = 0.06). CONCLUSIONS: Although our VTE rate reduced by 0.4 % and our VTE-related mortality reduced by 0.04 % after introduction of chemical thromboprophylaxis, these differences were not statistically significant. Chemical thromboprophylaxis may not be required in all patients undergoing arthroplasty providing appropriate mechanical prophylaxis is used.

A national survey of United Kingdom trauma units on the use of pelvic binders.

PURPOSE: Major pelvic injuries resulting from high-energy trauma require emergency hospital treatment, and part of the initial management includes mechanical stabilisation of the pelvis. Controversies include binder position, use in lateral compression injuries and application during radiological assessment. We present the results of a survey of both emergency department and orthopaedic specialties. METHODS: A telephone survey of all 144 trauma units in the UK accepting adult pelvic trauma patients was carried out in July 2012. The duty registrar for the emergency and orthopaedic departments was contacted and asked to complete a questionnaire. RESULTS: A response rate of 100% was achieved. Pelvic binders were available for use in approximately three quarters of the trauma units surveyed. Eight-five emergency department (59%) and 79 orthopaedic (54.9%) registrars had been given training on pelvic binder application. Fifty-six emergency department (38.9%) and 114 orthopaedic (79.1%) registrars identified the level of the greater trochanters as the most suitable position for the binder. Forty-five emergency department (31.3%) and 58 orthopaedic (40.3%) registrars used pelvic binders in suspected lateral compression injuries. One hundred and twenty-six emergency department (87.5%) and 113 orthopaedic (78.5%) registrars would not release the binder during radiological assessment of the pelvis in a haemodynamically stable patient. CONCLUSION: There is great variability in practice amongst trauma units in the UK. Training must be formalised and provided as a mandatory part of departmental induction. The use of standardised treatment algorithms in trauma units and the Advanced Trauma and Life Support (ATLS) framework may help decision making and improve patient survival rates.

Chemical, corrosion and topographical analysis of stainless steel implants after different implantation periods.

The aim of this work is to examine the corrosion properties, chemical composition, and material-implant interaction after different periods of implantation of plates used to correct funnel chest. The implants are made of 316L stainless steel. Examinations are carried out on three implants: new (nonimplanted) and two implanted for 29 and 35 months. The corrosion study reveals that in the potential range that could occur in the physiological condition the new bar has the lowest current density and the highest corrosion potential. This indicates that the new plate has the highest corrosion resistance and the corrosion resistance could be reduced during implantation by the instruments used during the operation. XPS analysis reveals changes in the surface chemistry. The longer the implantation time the more carbon and oxygen are observed and only trace of elements such as Cr, Mo are detected indicating that surface is covered by an organic layer. On some parts of the implants whitish tissue is observed: the thickness of which increased with the time of implantation. This tissue was identified as an organic layer; mainly attached to the surface on the areas close to where the implant was bent to attain anatomical fit and thus where the implant has higher surface roughness. The study indicates that the chest plates are impaired by the implantation procedure and contact with biological environment. The organic layer on the surface shows that the implant did not stay passive but some reactions at the tissue-implant interface occurred. These reactions should be seen as positive, as it indicates that the implants were accepted by the tissues. Nevertheless, if the implants react, they may continue to release chromium, nickel, and other harmful ions long term as indicated by lower corrosion resistance of the implants following implantation.

Effects of the menstrual cycle on lower-limb biomechanics, neuromuscular control, and anterior cruciate ligament injury risk: a systematic review.

OBJECTIVE: Anterior cruciate ligament (ACL) injury has a devastating impact on physical and psychological disability. Rates of ACL rupture are significantly greater in females than males during the same sports. Hormonal mechanisms have been proposed but are complex and poorly understood. This systematic review evaluates the effects of menstrual cycle on: 1) lower-limb biomechanics, 2) neuromuscular control, and 3) ACL injury risk. METHODS: The MEDLINE, CINAHL, SPORTSDiscus, Web of Science, and Google Scholar databases were searched from inception to August 2016 for studies investigating the effects of the menstrual cycle on lower-limb biomechanics, neuromuscular control, and ACL injury risk in females. Three independent reviewers assessed each paper for inclusion and two assessed for quality. RESULTS: Seventeen studies were identified. There is strong evidence that: 1) greatest risk of ACL injury is within the pre-ovulatory phase of the menstrual cycle, and 2) females with greater ACL laxity in the pre-ovulatory phase experience greater knee valgus and greater tibial external rotation during functional activity. CONCLUSION: Females are at greatest risk of ACL injury during the pre-ovulatory phase of the menstrual cycle through a combination of greater ACL laxity, greater knee valgus, and greater tibial external rotation during functional activity. LEVEL OF EVIDENCE: Ib.

Biomechanical analysis of limited-contact plate used for osteosynthesis.

This paper presents the results of numerical analysis aimed at determining the state of stresses and displacements of compression plate used in osteosynthesis of tibia, carried out by applying finite element method using the ANSYS program. The analysis took into account two variants of the osteosynthesis. Variant I included the osteosynthesis in which plate was attached directly to the bone, in variant II, the plate was moved away from the bones by about 5 mm. Biomechanical characteristics of the corrective osteotomy plate-tibia was determined for implants made of Ti-6Al-4V alloy. The boundary conditions adopted for the analysis reflect phenomena occurring in a real system. Based on the results of the analysis relative displacements and reduced stresses in various components were determined as a function of the applied load within the range of F = 500-1500 N. The maximum forces, both variant I and variant II determined during analysis, ensure that the generated stress does not exceed yield strength of the material and compressive strength of the bone, and do not exceed safety movement in the fracture gap. In addition, it was found that the locking of the compressive plate to the bone has a little effect on the distribution of displacements and stresses on the plate-tibia system in the case of a simple fracture.

Total hip arthroplasty using cementless avantage cup in patients with risk of hip prosthesis instability.

BACKGROUND: The aim of the study was to assess total hip arthroplasty procedures using the cementless Avantage cup in women with additional risk factors for postoperative hip instability. MATERIAL AND METHODS: A total of 280 cementless Avantage and Avantage Reload cups were implanted in 260 women aged between 29 and 79 years (60.9 years on average) in the years 2004-2010. In 217 women, there was at least one additional risk factor for prosthesis dislocation. The survival of the cup was assessed by using the necessity of cup replacement as an endpoint of the study. The statistical analyses used the Fisher test to assess the difference in the necessity of revision surgery between the Avantage and Avantage Reload cups, and the Kaplan Meier method was used to evaluate the effective functioning time of the prosthesis. Additionally, tests were conducted on the surface layer of 2 not used and 4 removed cups. RESULTS: 239 patients (259 arthroplasties) were subjected to the final examination. The follow-up period ranged from 2.7 to 9.7 years, 7.0 years on average. None of the patients demonstrated postoperative prosthesis instability. Aseptic loosening was observed in 19 cups in 18 women (7.3%). Intra-prosthetic dislocation occurred 4 times, and in two cases it was combined with loosening of the cup. Revision surgery was required more often in patients with the Avantage cup (9.5%, 17 out of 179) in comparison to the Avantage Reload (2.5%, 2 out of 80). However, the observed differences did not reach the level of statistical significance. The cumulative survival rate of the Avantage cup was 0.94 at 5 years and 0.86 at 8 years. CONCLUSIONS: 1. Avantage cups reduce the risk of postoperative hip instability. 2. Patients with cementless Avantage cups should be closely monitored for signs of aseptic loosening.

Bilateral sleeve fracture of the inferior poles of the patella in a healthy child: case report and review of the literature.

The initial diagnosis of a sleeve fracture of the patella is key to a successful outcome with poor results well documented in the literature from delayed management. Diagnosis is difficult due to the rarity of this injury and thus the low likelihood the admitting junior doctor would think of this injury in their differential. They are very uncommon in incidence and have features on plain radiography that are difficult to interpret unless the surgeon is familiar with the anatomy of the immature patella. Missing the diagnosis can be disastrous for the patient. In this paper we describe the presentation of bilateral sleeve fractures in a healthy child, our initial investigations and subsequent management. We chose to repair with 5 Ethibond via 3 transosseous tunnels, initially reinforced with a circlage wire. On last review the boy maintains stable, pain-free knees with a full range of motion. The authors hope that this case and literature review will provide a valuable teaching aid and so assist in early, accurate diagnosis and cover the management options to achieve a positive outcome.