Primary Hip Replacement Surgery Research Articles

Older patients have the most to gain from orthopaedic enhanced recovery programmes

Between August 2007 and May 2009, 2128 consecutive patients underwent either primary hip or knee joint replacement surgery at our institute on an enhanced recovery pathway. We aimed to investigate the potential benefits of this pathway in patients over the age of 85 years. Data extracted from Hospital Episode Statistics were analysed. This data are prospectively collected and independently collated. In all patients median length of stay was reduced when compared with both our own data before the introduction of the pathway (6 to 4 days) and national averages over the same time period for both hip and knee replacements (5 to 4 days). Difference in length of stay was most pronounced in the group of patients aged 85 years and over (9 to 5 days for total hip replacement and 8 to 5 days for total knee replacement). Nearly all patients were discharged directly home (97.4%). Readmission rates were over 45% lower in patients aged 85 and over when compared with national averages (5.2 vs. 9.4%). This is the first series in the literature to assess the role of enhanced recovery pathways in the very elderly. This study not only shows that successful fast track rehabilitation can be achieved in the very elderly population undergoing elective joint replacement surgery, but that it is this cohort of vulnerable patients who have the most to gain from such multidisciplinary recovery programmes.

Influence of goal-directed therapy with balanced crystalloid–colloid or unbalanced crystalloid solution on base excess

To investigate changes in standard base excess (SBE) when administering two different infusion regimens for elective hip replacement within a goal-directed haemodynamic algorithm. This prospective, double-blind, randomized, controlled study enrolled patients scheduled for primary hip replacement surgery, who were randomized to receive either an unbalanced crystalloid (chloride: 155.5 mmol/l) or a 1 : 1 mixture of a balanced crystalloid and a balanced colloid (6% w/v hydroxyethyl starch 130/0.42; chloride: 98 and 112 mmol/l, respectively). Fluid management was goal-directed to optimize stroke volume using oesophageal Doppler. A total of 40 patients (19 female/21 male) participated in the study. After surgery, median (25-75% percentiles) SBE was significantly lower in the unbalanced group compared with the balanced group: -2.0 mmol/l (-3.1 to -1.1) versus -0.4 mmol/l (-1.2 to 0.7), respectively. This difference was mainly due to greater plasma chloride concentrations in the unbalanced group. The amount of study medication required to reach haemodynamic stability (median 1200 ml) did not differ between the two groups. SBE decreased in the unbalanced group without influence on fluid requirements and haemodynamic stability.

Body mass index is not a clinically meaningful predictor of patient reported outcomes of primary hip replacement surgery: prospective cohort study

To describe whether body mass index (BMI) is a clinically meaningful predictor of patient reported outcomes following primary total hip replacement (THR) surgery. Combined data from prospective cohort studies. We obtained information from four cohorts of patients receiving primary THR for osteoarthritis: Exeter Primary Outcomes Study (EPOS) (n = 1431); EUROHIP (n = 1327); Elective Orthopaedic Centre (n = 2832); and St. Helier (n = 787). The exposure of interest was pre-operative BMI. Confounding variables included: age, sex, SF-36 mental health, comorbidities, fixed flexion, analgesic use, college education, OA in other joints, expectation of less pain, radiographic K&L grade, ASA grade, years of hip pain. The primary outcome was the Oxford Hip Score (OHS). Regression models describe the association of BMI on outcome adjusting for all confounders. For a 5-unit increase in BMI, the attained 12-month OHS decreases by 0.78 points 95%CI (0.27-1.28), P-value 0.001. Compared to people of normal BMI (20-25), those in the obese class II (BMI 35-40) would have a 12-month OHS that is 2.34 points lower. Although statistically significant this effect is small and not clinically meaningful in contrast to the substantial change in OHS seen across all BMI groupings. In obese class II patients achieved a 22.2 point change in OHS following surgery. Patients achieved substantial change in OHS after THR across all BMI categories, which greatly outweighs the small difference in attained post-operative score. The findings suggest BMI should not present a barrier to access THR in terms of PROMs.

PP74 Comparing the Impact of Clinical Governance Policies in Different Countries: the Example of the English PROMS Programme

BackgroundThere is considerable variation at a country level in the use of health outcome measures to support clinical governance.In 2009 the NHS in England introduced Patient-Reported Outcome Measures (PROMs) as...

The association of patient characteristics and surgical variables on symptoms of pain and function over 5 years following primary hip-replacement surgery: a prospective cohort study

ObjectivesTo identify patient characteristics and surgical factors associated with patient-reported outcomes over 5 years following primary total hip replacement (THR).DesignProspective cohort study.SettingSeven hospitals across England and Scotland.Participants1431 primary hip replacements...

Serotonin Reuptake Inhibitors and Bleeding Risks in Major Orthopedic Procedures

Risk of abnormal bleeding in surgery patients prescribed serotonin reuptake inhibitors (SRIs) is unclear. Considering the quantity of literature on abnormal gastrointestinal (GI) bleeding with SRIs, relatively little exists on SRI bleeding risks in surgical procedures. We investigated whether SRIs increase the risk of surgical bleeding in patients undergoing knee and hip total joint replacement. RA retrospective case-control study was conducted among subjects undergoing primary total hip and knee replacement surgeries from January 2005 to March 2011 at a single institution. The experimental group was defined by utilization of SRIs at the time of surgery (the independent variable). The control group was matched for age, sex, ethnicity, and type of surgery (hip or knee). Any case with preoperative hematocrit <30, platelets <100,000; abnormal prothrombin time, partial-prothrombin time, and international normalized ratio (INR), primary bleeding disorder, medical conditions, or medications associated with increased bleeding was excluded. All cases were randomly selected. RA total of 194 subjects (hip 104, knee 90) were included. Statistical analysis was performed on the SRI group (n = 71) and the control, non-SRI group (n = 123). No difference was found between the groups in estimated blood loss, hemoglobin, hematocrit, platelets, PT, PTT, and INR from preoperative to postoperative day 1, 2, and 3. Furthermore, no subjects in either group required blood transfusions. SRIs were not associated with increased risk of bleeding in primary knee or hip replacement surgeries in this study. The hypothesis that SRIs increase the risk of bleeding based on presumptions about their action on platelet aggregation is uncertain and warrants further study.

Aspirin for elective hip and knee arthroplasty: a multimodal thromboprophylaxis protocol

Multimodal thromboprophylaxis includes preoperative thromboembolic risk stratification and autologous blood donation, surgery performed under regional anaesthesia, postoperative rapid mobilisation, use of pneumatic compression devices and chemoprophylaxis tailored to the patient's individual risk. We determined the 90-day rate of venous thromboembolism (VTE), other complications and mortality in patients who underwent primary elective hip and knee replacement surgery with multimodal thromboprophylaxis. A total of 1,568 consecutive patients undergoing hip and knee replacement surgery received multimodal thromboprophylaxis: 1,115 received aspirin, 426 received warfarin and 27 patients received low molecular weight heparin and warfarin with or without a vena cava filter. The rate of VTE, pulmonary embolism, proximal deep vein thrombosis (DVT) and distal DVT was 1.2, 0.36, 0.45 and 0.36 %, respectively, in patients who received aspirin. The rates in those who received warfarin were 1.4, 0.9, 0.47 and 0.47 %, respectively. The overall 90-day mortality rate was 0.2 %. Multimodal thromboprophylaxis in which aspirin is administered to low-risk patients is safe and effective following primary total joint replacement.

Development of a broad spectrum polymer‐released antimicrobial coating for the prevention of resistant strain bacterial infections

More than 400,000 primary hip and knee replacement surgeries are performed each year in the United States. From these procedures, approximately 0.5-3% will become infected and when considering revision surgeries, this rate has been found to increase significantly. Antibiotic-resistant bacterial infections are a growing problem in patient care. This in vitro research investigated the antimicrobial potential of the polymer released, broad spectrum, Cationic Steroidal Antimicrobial-13 (CSA-13) for challenges against 5 × 10(8) colony forming units (CFU) of methicillin-resistant Staphylococcus aureus (MRSA). It was hypothesized that a weight-to-weight (w/w) concentration of 18% CSA-13 in silicone would exhibit potent bactericidal potential when used as a controlled release device coating. When incorporated into a polymeric device coating, the 18% (w/w) broad-spectrum polymer released CSA-13 antimicrobial eliminated 5 × 10(8) CFU of MRSA within 8 h. In the future, these results will be utilized to develop a sheep model to assess CSA-13 for the prevention of perioperative device-related infections in vivo.

Pre-operative BMI as a predictor of patient reported outcomes of primary hip replacement surgery: a combined analysis of 4 prospective cohort studies

s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S152 study ,using the cell culturing technology, was to observe what different results would come out from the MTTassay of the ATDC5 cell proliferation, whick had been cultured with different concentration E2. Methods: The 17-bestradiol we use was ordered from Sigma co. and the ATDC5 cell line was form the Riken cell bank. We culture the ATDC5 24 hours in the media with different concentration 17-bestradiol, then we test the OD value of the different cells in MTT assay to assume the proliferation of the ATDC5. Results: After culturing 24 hours in the media with different concentration 17-bestradiol, the proliferation of the ATDC5 in different concentration 17-bestradiol were different significantly, the higher of the concentration, the higher of the proliferation, as follows: beside the 10-11M against 0 M, the 10-10,10-9,10-8 and 10-7 M have significant difference in stimulating the proliferation of ATDC5 against 0 M. between the different concentration groups, only 10-8 M has significant difference against 10-11,10-10 M. Conclusions: First, 17-bestradiol has stimulation on the proliferation of ATDC5. Second, 10-8 M concentration of 17-bestradiol has the strongest stimulating effect than the other concentration of 17-bestradiol. Clinical Aspects / Outcomes 302 PRE-OPERATIVE BMI AS A PREDICTOR OF PATIENT REPORTED OUTCOMES OF PRIMARY HIP REPLACEMENT SURGERY: A COMBINED ANALYSIS OF 4 PROSPECTIVE COHORT STUDIES R.N. Batra , A. Judge , M.K. Javaid , G.E. Thomas , D. Beard , D. Murray , P. Dieppe , K. Drienhoefer , K. Peter-Geunther , R. Field , C. Cooper , N.K. Arden . NIHR BioMed. Res. Unit, Univ. of Oxford, Oxford, United Kingdom; MRC Lifecourse Epidemiology Unit, Univ. of Southampton, Southampton, United Kingdom; 3 Peninsula Coll. of Med. and Dentistry, Plymouth, United Kingdom; Charite Univ.smedizin Berlin, Dept. of Orthop., Traumatology and Sports Med., Berlin, Germany; Univ. Hosp. Carl Gustav Carus, Technical Univ. of Dresden, Dresden, Germany; 6 Elective Orthop. Ctr., Epsom, United Kingdom Purpose: Total hip replacement (THR) is a successful surgical intervention, providing relief from pain, increasingmobility and improving quality of life for majority of patients. Within the literature some, but not all studies, have found that obesity is associated with worse patient reported outcomes (PROMs) of THR, and there is increasing concern that obesity may be used as a barrier to accessing surgery. Methods: We obtained information from 4 prospective cohort studies of patients receiving primary THR for osteoarthritis (OA): Exeter Primary Outcomes Study (EPOS) (n1⁄41589); EUROHIP (n1⁄4908); South West London Elective Orthopaedic Centre (SWLEOC) (n1⁄41523); and St. Helier (n1⁄4799). The primary outcome was the 12 month Oxford Hip Score (OHS) which is used to assess pain and function.For the EUROHIP study, we imputed the OHS from WOMAC scores using truncated regression. Confounding variables included: age, sex, SF-36 mental health, comorbidities, fixed flexion, analgesic use, college education, OA in other joints, expectation of less pain, radiographic KL only age and sex were available in all 4 cohorts. Linear regression (ANCOVA) is used to describe the association of BMI on the 12 month OHS, adjusting for the pre-operative OHS. Multiple imputation methods were used to handle missing data. In order to combine data across the 4 studies we used two methodological approaches: a) Meta-Analysis For each study, separate models are built to describe the association of BMI on outcome. Models are adjusted only for age and sex in order to construct related hypotheses in each study. Fixed effects metaanalysis is used to combine the results; b) Combining studies Data from all 4 studies are combined using multiple imputation methods to impute data on missing confounders, allowing the association of BMI on outcome to be adjusted for all potential confounders. Results: a) Meta-Analysis Adjusting for age and sex, for a 5 unit increase in BMI, the 12 month OHS decreases by 0.81 95%CI (0.55 1.08) units (Figure 1); Ă b) Combining Studies Adjusting for age and sex alone, for a 5 unit increase in BMI, the 12 month OHS decreases by 0.72 (0.46 0.99) units. Adjusting for all potential confounders, the effect is attenuated to 0.51 (0.09 0.92). Hence, for each 5 unit increase in BMI, the difference in post-op OHS becomes larger and more important. For example, compared to people with a normal BMI (20 25), those in the morbidly obese group (BMI 35 40) would have a post-op OHS that is 1.53 units lower. However, there is a substantial improvement in OHS after THR across all BMI groups, which greatly outweighs any difference in post-op score (Figure 2).

An Analysis of Bone Donor Deferral Rates in Scotland – a 6-Year Study

Background: The Scottish National Blood Transfusion Service (SNBTS) is the main provider of tissues in Scotland. Tissue collection programmes were established in the mid-1990s, and the range of tissues collected has increased progressively over the years. Methods: Whilst the majority of tissues are obtained from cadaveric donations, bone is collected only from living donors who are usually patients undergoing primary hip replacement surgery (surgical donors). The bone is collected in an operating theatre, and, once stored, no further processing takes place prior to issue. Bone that fails for any reason (quality, microbiology or virological nonnegative result) is discarded. Results: The deferral rate amongst live surgical bone donors in Scotland is around 65%, and it has been slowly and progressively rising from around 55% over the past few years. This needed investigated, particularly because comparisons with blood donors show that the deferral rate amongst bone donors is more than double that of first-time blood donors (29.7%). Our processes and systems are standardised, and our cohort of bone bank nurses have all been similarly trained and competency assessed. Moreover our data collection was done in a uniform fashion. It was therefore possible to conduct a 6-year audit on bone donor deferrals. It was found that a history of transfusion (16%), history of malignancy (18%) and bone quality (26%) were the main reasons for bone donor deferrals, accounting for 60% of all deferrals. Conclusions: When these are taken into account, the residual deferral rates become very similar numerically to blood donors. It is important to note however that there are significant differences between the blood and bone donor cohorts. This study also highlighted some of deferral reasons. Particularly malignancy is a cause of significant numbers of deferrals, and the evidence of transmissibility of malignancy through bone donation is not strong. More robust risk assessments should be undertaken prior to implementing deferral conditions.

Surgical site infections in primary total hip and knee replacement surgeries, hemiarthroplasties, and osteosyntheses at a Brazilian university hospital

We report a case-control study involving 663 primary orthopedic surgeries with a 12.7% rate of surgical site infections (SSIs). The respective frequencies of superficial incisional, deep incisional, and organ/space infections were 22.2%, 44.5%, and 33.3% for total hip arthroplasties; 66.7%, 33.3%, and 0% for total knee arthroplasties; 0%, 75.0% and 25.0% for hemiarthroplasties; and 44.1%, 35.3%, and 20.6% for osteosyntheses. These rates of SSIs are higher than those reported in previous studies.

Localisation and Identification of Bacteria In The Skin of Patients Undergoing Primary Knee and Hip Replacement Surgery After Surgical Skin Preparation

Localisation and Identification of Bacteria In The Skin of Patients Undergoing Primary Knee and Hip Replacement Surgery After Surgical Skin Preparation

Reallocation of Foundation Programme Doctors From Teams to Wards Reduces Mortality From Proximal Femoral Fracture

Reallocation of Foundation Programme Doctors From Teams to Wards Reduces Mortality From Proximal Femoral Fracture

Cost effective interprofessional training: An evaluation of a training unit in Denmark

In 2004, the first Danish undergraduate interprofessional training unit (ITU) was established at the Regional Hospital Holstebro, inspired by experiences from Sweden. In this unit, medical, nursing, occupational therapy and physiotherapy students are given responsibility, under supervision by trained and motivated personnel, for rehabilitation and care of patients in a subunit of an orthopaedic department. The aim of this study was to see whether the ITU was cost effective in treating patients compared with a conventional orthopaedic ward. One-hundred and thirty-four patients admitted for primary hip or knee replacement surgery were included in the study. All costs were recorded in the ITU and in the conventional ward. Follow-up was done by a quality of life questionnaire three months after the operation. Comparison was done by univariable and multivariable testing of costs and effect. In both, the ITU was more cost effective than the conventional ward. No difference was found in complications and patient-reported quality of life. In conclusion, clinical training can be given to students in an ITU without reducing productivity in a hospital environment if pedagogic principles, clinical tutors and patient logistics all adapt to the challenge of the teaching environment.

Predicting Patient Dissatisfaction Following Joint Replacement Surgery

The incidence of patient-reported dissatisfaction following total joint arthroplasty can be up to 30%. Our aim was to identify the preoperative patient-level predictors of patient dissatisfaction 1 year after surgery. We surveyed 1720 patients undergoing primary hip or knee replacement surgery. Relevant covariates including demographic data, body mass index, sex, comorbidities, and education were recorded. Joint functional status and patient quality of life were assessed at baseline and at 1-year followup with the Western Ontario McMaster University Osteoarthritis Index (WOMAC) and Medical Outcomes Study Short Form-36 (SF-36) scales, respectively. Patient satisfaction with surgery was determined with 4 survey questions at 1-year followup. There were no significant differences in demographic data between satisfied (n = 1290) and dissatisfied patients (n = 430). Logistic regression modeling showed that a lower preoperative SF-36 Mental Health score independently predicted patient dissatisfaction with surgery, adjusted for all relevant covariates (p < 0.05). We found no correlation between patient satisfaction and WOMAC change scores at 1-year followup (p = 0.31). Preoperative mental health is an important factor to consider when understanding patient satisfaction with surgery. Interventions to reduce psychological distress prior to surgery should be studied to determine if they may improve subjective outcomes of patients undergoing joint replacement surgery.

Relationship between self-reported and performance-based tests in a hip and knee joint replacement population

Our objectives were: (1) to assess the relationship between self-reported measures (Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Medical Outcomes Study Short Form-36 (SF-36)) and a performance-based timed-up-and-go (TUG) test in a hip and knee joint replacement population and (2) to determine the predictors of postoperative functional status as measured by the 12-week WOMAC and TUG scores. We surveyed 200 patients undergoing primary hip or knee replacement surgery for demographic data and outcome scores at baseline and 12-week follow-up. There was a weak correlation between preoperative TUG scores and preoperative SF-36 physical function scores (r = -0.28, p < 0.0001), SF-36 role-physical scores (r = -0.21, p = 0.0022) and WOMAC (r = 0.29, p < 0.0001) scores. The relationship was stronger between the postoperative TUG scores and WOMAC scores (r = 0.43, p < 0.0001), SF-36 physical function scores (r = -0.39, p < 0.0001) and SF-36 role-physical (r = -0.33, p < 0.0001) scores. Significant predictors for the TUG test at 12-week follow-up were age (p = 0.004) and preoperative TUG scores (p < 0.0001). Given low-to-moderate relationship between self-reported and performance-based tools, both tests are needed to assess the true level of patient disability.

Trabecular Metal Endoprosthetic Limb Salvage Reconstruction of the Lower Limb

Currently, porous tantalum (trabecular metal) implants are widely accepted and frequently used for primary and revision hip and knee replacement surgery. This study examines the results of porous tantalum endoprostheses used to reconstruct large skeletal defects following resection of bone tumors. Seven custom tantalum implants were used to reconstruct 7 patients following resection for skeletal sarcomas in the femur and proximal tibia. Patient ages ranged from 13 to 71, with a mean of 34 years. Minimum patient follow-up was 6 years. The average Musculoskeletal Tumor Society functional evaluation score was 95 % of normal. There were no infections, hardware failures, or adverse events. One implant was revised 98 months post insertion because of fibrosis, loss of motion and loosening. In this small clinical series, the use of porous tantalum for limb salvage reconstruction is shown to be safe, to successfully provide osteointegration and soft tissue ingrowth, and to facilitate return of limb girdle muscle function.

Willingness to go through surgery again validated the WOMAC clinically important difference from THR/TKR surgery

Objective The objective was to determine the clinically important difference (CID) from primary total hip replacement (THR) and total knee replacement (TKR) surgeries using the Western Ontario McMaster University (WOMAC) osteoarthritis index. Study Design and Setting WOMAC scores were collected at decision for and 1 year after surgery ( n = 2,709). Transition ratings (15-point scale) were obtained at 1 year for pain and function, as well as a global assessment of willingness to go through surgery again. A “good deal better” defined the positive CID. WOMAC change scores for transition ratings and willingness to go through surgery again were evaluated using receiver operating characteristic curves. Patient characteristics within transition rating categories were examined. Results For THR, the positive CIDs were 41 of 100 for pain and 34 of 100 for function. The negative CIDs were 35 and 33, respectively. For TKR, the positive CIDs were 36 for pain and 33 for function. The negative CIDs were 30 and 25, respectively. Change scores for willingness to go through surgery again validated CID values. Postoperative complications decreased the likelihood of a positive CID. Conclusion Improvement that is “a good deal better” is an appropriate threshold for the THR/TKR positive CID. Attaining a positive CID is negatively related to postoperative complications.

Once Daily YM150, an Oral Direct Factor Xa Inhibitor, for Prevention of Venous Thromboembolism in Patients Undergoing Elective Primary Hip Replacement.

YM150 is an orally active direct FXa inhibitor in clinical development. Proof of concept of YM150 was previously obtained in a dose escalation study, demonstrating a statistically significant dose-related trend in VTE prevention in patients undergoing total hip replacement (ONYX; J Thromb Haemost 2007; 5:1660–5). The present study with YM150 is a double blind, parallel, multi-center dose finding study in patients undergoing elective primary hip replacement surgery, with open label enoxaparin as control. Patients were randomly treated with 5, 10, 30, 60 or 120 mg YM150 once daily orally or 40 mg enoxaparin once daily subcutaneously. Patients were treated in hospital for approximately 1–2 weeks followed by home treatment for another 4 weeks, for in total 33–38 treatment days (prolonged treatment for hip replacements according to guidelines of Am. College of Chest Physicians (Geerts et al. Chest 2004: 126;338–400)). The administration of YM150 started 6–10 h after surgery, while treatment with enoxaparin started 12 ± 2 h before surgery. Mandatory bilateral venography was performed after 7–10 days of treatment. Follow up visits were performed at 2 and 4 weeks during home treatment, and 2, 4, and 8 weeks after end of study treatment. The sample size was estimated to be 960 randomized patients in order to yield 110 patients per treatment group with an evaluable venogram. The primary efficacy endpoint was defined as deep vein thrombosis, and/or symptomatic VTE and/or death, and primary safety endpoint as the incidence of major bleeding during the first 7–10 days of study treatment. Secondary efficacy endpoints were proximal and distal DVT (during the first 7–10 days) and symptomatic VTE during home treatment, and follow up. Secondary safety endpoints were the incidences of major, clinically relevant non-major (CRNM) and minor bleeding during the three study periods. Independent Adjudication Committees reviewed all venograms, bleeding reports, symptomatic VTEs, and deaths unaware of treatment allocation. An independent DSMB monitored the data to ensure the safety of the patients. 1017 patients were randomized from 81 sites in 17 European countries. Preliminary data showed that DVT was detected in 149 out of 727 evaluable venograms, one patient had symptomatic VTE, and one patient died (myocardial infarction) during the hospital treatment period. This results in a total primary efficacy outcome rate of 20.7% (151/729) in the evaluable study population, with a corresponding rate of major bleeding of 0.6% (6/1017). The breakdown of the results according to treatment group will be presented.

A dose escalation study of YM150, an oral direct factor Xa inhibitor, in the prevention of venous thromboembolism in elective primary hip replacement surgery.

YM150, a new oral direct factor Xa inhibitor is used as prophylaxis for venous thromboembolism (VTE), a well-known risk after orthopaedic surgery. To assess the safety and efficacy of thromboprophylaxis with YM150 in a dose escalation study. Patients (174) undergoing hip replacement surgery were randomized per cohort to oral once daily YM150 or subcutaneous enoxaparin (40 mg daily) in a 4:1 ratio for 7-10 days treatment. The YM150 doses were 3, 10, 30 and 60 mg by sequential four-dose escalation cohorts. The primary endpoint was major and/or clinically relevant non-major bleeding. The incidence of VTE was defined as a composite of verified symptomatic events and/or positive findings at bilateral venography on the last treatment day. An independent adjudication committee evaluated blindly the outcomes of the open-label study. No major and three clinically relevant non-major bleeds were reported, 1 (2.9%; 95% CI, 0.1-15.1) in the 3 mg and 2 (5.7%; 95% CI, 1.0-18.8) in the 10 mg YM150 dose groups. Of 147 patients (84%) with an evaluable venogram, VTE was observed in 51.9% (95% CI, 31.9-71.4), 38.7% (95% CI, 22.6-57.0), 22.6% (95% CI, 9.7-39.4), and 18.5% (95% CI, 7.5-36.5) in the YM150 dose groups 3, 10, 30 and 60 mg, respectively. A significant YM150 dose-related trend in VTE incidence was found (P=0.006). VTE with enoxaparin was 38.7% (95% CI, 22.6-57.0). YM150, 10-60 mg daily, starting 6-10 h after primary hip replacement, was shown to be safe, well tolerated and effective.