Hip fracture is associated with highest mortality following trauma in the elderly. The objective of this study is to evaluate the association between duration of anaesthesia and duration of surgery with 30 days mortality following hip fracture surgery. This retrospective cohort study reviewed patients underwent surgery following hip fracture in a district general hospital. Patients less than 65 years, periprosthetic and pathological fractures were excluded. Totally 254 patients were included in the study, who had surgery between February 2005 and September 2008 (20 months period). Mortality details retrieved through National Statistics database. Chi Square tests and Logistic regression analyses were performed to check the relationship between 30 days mortality and all independent variables including duration of anaesthesia and duration of surgery. The incidence of 30 days mortality following hip fracture surgery was 9.4%. The commonest reason of death was cardiac failure and chest infection. Patients who had General anesthesia (GA) had more complications and mortality in comparison with those who had regional anaesthesia. GA increases the odds of 30 days mortality to 2.5 times. Patients under American Society of Anesthesiologists (ASA) II had decreased odds of 30 days mortality than ASA III & IV (odds Ratio 0.16). However duration of anesthesia up to 120 minutes and duration of surgery up to 90 minutes were not associated with 30 days mortality (P>0.05). The 30 days mortality following dynamic hip screw fixation surgery was 14.6% and intra medullary nail was 12.5%. The 30 days mortality in cemented hemi-arthroplasty was 6.9% and uncemented hemi-arthroplasty was 6%. The 30 days mortality was nil in the group of patients who had undergone cannulated hip screw fixation. In elderly people following hip fracture surgery 30 days mortality was not affected by duration of anaesthesia and duration of surgery. However 30 days mortality was related with GA, ASA III & IV and post-operative complications mainly cardiac failure and chest infection. These patients need specialist medical care

Previous studies have indicated that prolonged surgical time may lead to higher rates of infection following total hip arthroplasty (THA). The purpose of this study was to evaluate the influence of surgical time on 30-day complications following THA and to determine if there was a time interval associated with worse outcomes. Patients ≥18 years who underwent THA between 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database using procedural codes. Patients with surgical durations >240 minutes were excluded. Patient demographics, operation length, and 30-day major and minor complications were ascertained. Multivariable regression was used to determine if the rate of complications differed depending on length of operation, while adjusting for relevant covariables, and to identify independent predictors of operation length. Covariables of interest included age, sex, American Society of Anaesthesiologists (ASA) class, smoking status, functional status, comorbidities, anesthesia type, and Body Mass Index (BMI). A total of 131,361 THA patients (average age 65 ±12 years) were identified from the database. Of these, 2,177 (1.64%) experienced a major complication, and 3,504 (2.64%) experienced a minor complication within 30-days of the initial procedure. Average operation length was 91.9 minutes (range 20 – 240 minutes). Independent predictors of prolonged operation length included overweight/obese BMI, male sex, cancer, dependent functional status, epidural anaesthetic, lower pre-operative hematocrit, and ASA class II, III or IV vs. I Alternatively, older age, current smoking, and spinal anaesthetic were associated with shorter surgical durations. Unadjusted rates of both major and minor complications were significantly higher for patients whose operation lengths were ≥ 120 minutes (P>0.001). Specifically, patients whose operations lasted ≥ 120 minutes had higher rates of septic shock, sepsis, pulmonary embolism (PE), deep vein thrombosis (DVT), urinary tract infection (UTI), renal insufficiency, surgical site infection(SSI) and wound disruption. After covariable adjustment, surgical durations of 90–119 minutes increased the risk of minor complications by 1.2 (95%Confidence interval [95%CI] 1.1–1.3), while surgical durations of 120–179 minutes increased the risk of major complications by 1.4 (95%CI 1.3 – 1.6), and minor complications by 1.4 (95%CI 1.2 – 1.5), and surgical durations ≥180 minutes increased the risk of major complications by 2.1 (95%CI 1.8 – 2.6), and minor complications by 1.9 (95%CI 1.6 – 2.3). There was no difference in the overall risk of complications for operation times lasting 20 – 39, 40 – 59, or 60 – 89 minutes (P>0.05). In terms of specific complications, operation length ≥90 minutes was determined to be an independent risk factor for deep and superficial incisional SSI, as well as wound disruption, while operation length ≥ 120 minutes was an independent risk factor for sepsis, UTI, and deep, non-incisional SSI and operation length ≥ 180 minutes was an independent risk factor for PE, DVT, and cardiac arrest (p < 0 .05). These data indicate that prolonged surgical durations may be an independent predictor of major and minor complications following THA. This suggests that quality improvements could be made to improve operating room efficiency and surgical times and therefore postoperative outcomes

Introduction. In recent years, many studies demonstrated the efficacy of an early switch to oral antibiotics after surgical treatment in orthopaedic related infections. However, large analyses on periprosthetic joint infections (PJIs) are lacking. Material and Methods. We conducted a retrospective observational multicenter study in patients diagnosed with an early postoperative PJI (i.e less than 3 months after the index arthroplasty) treated with debridement, antibiotics and implant retention (DAIR). Patients from Europe and the USA were included. These two cohorts served as a quasi-randomised trial since an early oral antibiotic switch is routine practice in Europe versus a long duration of intravenous (IV) antibiotic treatment in the USA. Failure was defined as the clinical need for: i) a second DAIR, ii) implant removal, iii) suppressive antibiotic treatment or iv) infection related death. Results. A total of 668 patients were included. 277 received IV antibiotics for <14 days, 232 were given IV antibiotics between 14 - 27 days and 159 received IV antibiotics for >27 days. The overall 1-year failure rate within the 3 groups was 41.5%, 44.4% and 42.1%, respectively (P 0.80), and mainly comprised the need for a second DAIR. The results did not change when analyzing patients with or without obesity, the causative microorganism or the type of oral antibiotics. Conclusion. In early postoperative PJIs, a longer duration of IV antibiotic treatment is not associated with a lower failure rate of a DAIR procedure

Aim. Due to medical and organizational factors, it occurs in everyday practice that spacers are left in place longer than originally planned during a two-stage prosthesis exchange in the case of prosthetic joint infections. Patients are severely restricted in their mobility and, after initial antibiotic administration, the spacer itself only acts as a foreign body. The aim of this study is to analyze whether the duration of the spacer in situ has an influence on the long-term success of treatment and mortality. Method. We retrospectively studied all 204 two-stage prosthesis replacements of the hip and knee from 2012 to 2016 with a minimum follow-up of two years at an arthroplasty center with 3 main surgeons. The duration of the spacer interval was divided into two groups. Patients replanted within ten weeks (as is standard in multiple algorithms) after systemic antibiotic treatment were assigned to the ‘Regular Spacer Interval (< 70 days)’ group. If the spacer interval was longer, they were assigned to the ‘Long Spacer Interval (≥ 70 days)’ group. Results. Patients were on average 67.69 years old (SD 12.3). The mean duration of the spacer-interval was 100.9 days (range: 423.0; SD, 60.0). In 62 patients reimplantation could be performed within 70 days after explantation, in 142 patients this took longer (max. 438 days). In 26 patients, the spacer had to be changed at least once during this period (11 patients in the hip group, and 15 patients in the knee group). In the remaining cases, other medical or organizational reasons delayed replantation. Both groups were comparable concerning Charlson Comorbity Index, age, number of previous surgeries and laboratory infection markers. There was no statistically significant influence of the duration of the spacer interval on the infection free survival (n=204, p=0.32). There was also no influence on mortality (n=204, p=0.35) and aseptic implant failure (n=204, p=0.15). Conclusions. The timely replantation of a knee or hip prosthesis seems to be reasonable in general because the patients are strongly limited in their mobility and daily activities by the spacer. However, there does not seem to be a negative influence on infection eradication and survival due to a long spacer interval

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

Single level discectomy (SLD) is one of the most commonly performed spinal surgery procedures. Two key drivers of their cost-of-care are duration of surgery (DOS) and postoperative length of stay (LOS). Therefore, the ability to preoperatively predict SLD DOS and LOS has substantial implications for both hospital and healthcare system finances, scheduling and resource allocation. As such, the goal of this study was to predict DOS and LOS for SLD using machine learning models (MLMs) constructed on preoperative factors using a large North American database. The American College of Surgeons (ACS) National Surgical and Quality Improvement (NSQIP) database was queried for SLD procedures from 2014-2019. The dataset was split in a 60/20/20 ratio of training/validation/testing based on year. Various MLMs (traditional regression models, tree-based models, and multilayer perceptron neural networks) were used and evaluated according to 1) mean squared error (MSE), 2) buffer accuracy (the number of times the predicted target was within a predesignated buffer), and 3) classification accuracy (the number of times the correct class was predicted by the models). To ensure real world applicability, the results of the models were compared to a mean regressor model. A total of 11,525 patients were included in this study. During validation, the neural network model (NNM) had the best MSEs for DOS (0.99) and LOS (0.67). During testing, the NNM had the best MSEs for DOS (0.89) and LOS (0.65). The NNM yielded the best 30-minute buffer accuracy for DOS (70.9%) and ≤120 min, >120 min classification accuracy (86.8%). The NNM had the best 1-day buffer accuracy for LOS (84.5%) and ≤2 days, >2 days classification accuracy (94.6%). All models were more accurate than the mean regressors for both DOS and LOS predictions. We successfully demonstrated that MLMs can be used to accurately predict the DOS and LOS of SLD based on preoperative factors. This big-data application has significant practical implications with respect to surgical scheduling and inpatient bedflow, as well as major implications for both private and publicly funded healthcare systems. Incorporating this artificial intelligence technique in real-time hospital operations would be enhanced by including institution-specific operational factors such as surgical team and operating room workflow

Introduction. Frame configuration for the management of complex tibial fractures is highly variable and is dependent not only on fracture pattern and soft tissue condition but also surgeon preference. The optimal number of rings to use when designing a frame remains uncertain. Traditionally, larger, stiffer constructs with multiple rings per segment were thought to offer optimal conditions for bone healing, however, the concept of reverse dynamisation questions this approach. Materials & Methods. We compared clinical outcomes in 302 consecutive patients with tibial fractures treated in our unit with either a two-ring circular frame or a three-or-more-ring (3+) frame. The primary outcome measure was time spent in frame. Secondary outcomes were the incidence of malunion and the need for further surgical procedures to achieve bone union. The groups were evenly matched for age, co-morbidities, energy of injury mechanism, fracture classification, post-treatment alignment and presence of an open fracture. Results. The mean time in frame was 168 days for the 2-ring group and 200 days for the 3+ rings group (p=0.003). No significant difference was found in the rate of malunion (p=0.428) or the requirement for secondary surgical intervention to achieve union (p=0.363). No significant difference in time in frame was found between individual surgeons. Conclusions. This study finds that 2-ring frame constructs are a reliable option associated with significantly shorter duration of treatment and no increase in rates of adverse outcomes compared with larger, more complex frame configurations. Although this study cannot identify the underlying cause of the difference in treatment time between frame designs, it is possible that differences in mechanical stability lead to a more favourable strain environment for fracture healing in the 2-ring group

Aim. The purpose of this study is to report the overall infection control rate and prognostic factors associated with acute, hematogenous and chronic PJIs treated with DAIR. Methods. All DAIR procedures performed at 2 institutions from 2009 to 2018 (n=104) were reviewed and numerous data were recorded, including demographics, preoperative laboratory tests, Charleston Comorbidity Index, surgical information and organism culture results. Treatment success was defined according to the criteria reported by Diaz-Ledezma. A multivariable analysis was utilized to identify prognostic factors associated with treatment and a Kaplan-Meier survival analysis was used to depict infection control rate as a function of time. Results. The overall treatment success rate in the current cohort of patients was 67.3% at a median 38.6 (23.5–90.7) months follow-up. Patients with a duration of infectious symptoms greater than 10 days were more likely to fail (P=0.035, odds ratio 8.492, 95% confidence interval 1.159–62.212). There was no difference among acute, hematogenous and chronic infections in terms of failure rate even when time was considered (p=0.161). Conclusion. With careful patient selection, DAIR is a reasonable treatment option for PJI and its use in the setting of chronic infection does not appear to be a contraindication. Performing the DAIR procedure within 10 days of the presentation of symptoms had higher rates of treatment success

Aim. Duration of perioperative antimicrobial prophylaxis (PAP) remains controversial in prevention of fracture-related infection (FRI) – with rates up to 30% - in open fracture (OF) management. Objectives were to investigate the impact of the PAP duration exclusively in or related to long bone OF trauma patients and the influence of augmented renal clearance (ARC), a known phenomenon in trauma patients, as PAP consists of predominantly renally eliminated antibiotics. Method. Trauma patients with operatively treated OF, admitted between January 2003 and January 2017 at the University Hospitals Leuven, were retrospectively evaluated. FRI was defined following the criteria of the consensus definition of FRI. A logistic regression model was conducted with FRI as outcome. Results were considered statistically significant when p< 0.05. Results. Forty (8%) from the 502 patients developed a FRI, with 20% FRIs in Gustilo-Anderson (GA) III OFs. Higher GA grade and polytrauma were independently associated with the occurrence of FRI. The heterogeneity in OF management, especially with regard to the applied PAP regimens and duration, was striking and consequently hampering the investigation on the impact of PAP duration. To overcome this issue, a subgroup analysis was performed in patients treated with the two PAP regimens as defined in the hospitals' guidelines – i.e. cefazolin, with metronidazole and tobramycine when extensive contamination was present -, revealing flap coverage and relative duration of augmented renal ARC as independently associated factors. Conclusions. For the first time, a definition based on diagnostic criteria was used to objectively include patients with a FRI. In order to support clinicians in establishing strategies to prevent FRI in long bone OFs, further prospective large randomized controlled trials with clearly predefined PAP regimens are needed to provide reliable recommendations regarding the impact of duration of PAP and ARC

Total knee and hip arthroplasty (TKA and THA) are two of the highest volume and resource intensive surgical procedures. Key drivers of the cost of surgical care are duration of surgery (DOS) and postoperative inpatient length of stay (LOS). The ability to predict TKA and THA DOS and LOS has substantial implications for hospital finances, scheduling and resource allocation. The goal of this study was to predict DOS and LOS for elective unilateral TKAs and THAs using machine learning models (MLMs) constructed on preoperative patient factors using a large North American database. The American College of Surgeons (ACS) National Surgical and Quality Improvement (NSQIP) database was queried for elective unilateral TKA and THA procedures from 2014-2019. The dataset was split into training, validation and testing based on year. Multiple conventional and deep MLMs such as linear, tree-based and multilayer perceptrons (MLPs) were constructed. The models with best performance on the validation set were evaluated on the testing set. Models were evaluated according to 1) mean squared error (MSE), 2) buffer accuracy (the number of times the predicted target was within a predesignated buffer of the actual target), and 3) classification accuracy (the number of times the correct class was predicted by the models). To ensure useful predictions, the results of the models were compared to a mean regressor. A total of 499,432 patients (TKA 302,490; THA 196,942) were included. The MLP models had the best MSEs and accuracy across both TKA and THA patients. During testing, the TKA MSEs for DOS and LOS were 0.893 and 0.688 while the THA MSEs for DOS and LOS were 0.895 and 0.691. The TKA DOS 30-minute buffer accuracy and ≤120 min, >120 min classification accuracy were 78.8% and 88.3%, while the TKA LOS 1-day buffer accuracy and ≤2 days, >2 days classification accuracy were 75.2% and 76.1%. The THA DOS 30-minute buffer accuracy and ≤120 min, >120 min classification accuracy were 81.6% and 91.4%, while the THA LOS 1-day buffer accuracy and ≤2 days, >2 days classification accuracy were 78.3% and 80.4%. All models across both TKA and THA patients were more accurate than the mean regressors for both DOS and LOS predictions across both buffer and classification accuracies. Conventional and deep MLMs have been effectively implemented to predict the DOS and LOS of elective unilateral TKA and THA patients based on preoperative patient factors using a large North American database with a high level of accuracy. Future work should include using operational factors to further refine these models and improve predictive accuracy. Results of this work will allow institutions to optimize their resource allocation, reduce costs and improve surgical scheduling. Acknowledgements:. The American College of Surgeons National Surgical Quality Improvement Program and the hospitals participating in the ACS NSQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors

Dexmedetomidine, an alpha 2 agonist, has been approved for providing sedation in the intensive care unit. Along with sedative properties, it has analgesic activity through its highly selective action on alpha 2 receptors. Recent studies have examined the use of dexmedetomidine as an adjuvant to prolong the duration of peripheral nerve blocks. Studies showing effectiveness of dexmedetomidine for adductor canal block in knee surgery are small. Also, its effectiveness has not been compared to Epinephrine which is a strong alpha and beta receptor agonist. In a previous study, we showed that motor sparing knee blocks significantly increased the duration of analgesia compared with periarticular knee infiltration using local anesthetic mixture containing Epinephrine following total knee arthroplasty (TKA). In this study, we compared two local anesthetic mixtures: one containing Dexmedetomidine and the other Epinephrine for prolongation of motor sparing knee block in primary TKA patients. After local ethics board approval and gaining Notice of Compliance (NOC) from Health Canada for use of Dexmedetomidine perineurally, 70 patients between the ages 18 – 95 of ASA class I to III undergoing unilateral primary total knee arthroplasty were enrolled. Motor sparing knee block − 1) Adductor canal continuous catheter 2) Single shot Lateral Femoral Cutaneous Nerve block 3) Single shot posterior knee infiltration was performed in all patients using 60 ml mixture of 0.5% Ropivacaine, 10 mg Morphine, 30 mg Ketorolac. Patients randomized into the Dexmedetomidine group (D) received, in addition to the mixture, 1mcg/kg Dexmedetomidine and the Epinephrine (E) group received 200mcg in the mixture. The primary outcome was time to first rescue analgesia as a surrogate for duration of analgesia and secondary outcomes were NRS pain scores up to 24 hours and opioid consumption. The time to first rescue analgesia was not significantly different between Epinephrine and dexmedetomidine groups, Mean and SD 18.45 ± 12.98 hours vs 16.63 ± 11.80 hours with a mean difference of 1.82 hours (95% CI −4.54 to 8.18 hours) and p value of 0.57. Pain scores at 4, 6, 12, 18 and 24 hours were comparable between groups. Mean NRS pain scores Epinephrine vs Dexmedetomidine groups were 1.03 vs 0.80 at 4 hours, 1.48 vs 3.03 at 6 hours, 3.97 vs 4.93 at 12 hours, 5.31 vs 6.18 and 6.59 v 6.12 at 24 hours. Opioid consumption was also not statistically significant between both groups at 6, 12 18, 24 hours (p values 0.18, 0.88, 0.09, 0.64 respectively). Dexmedetomidine does not prolong the duration of knee motor sparing blocks when compared to Epinephrine for total knee arthroplasty. Pain scores and opioid consumption was also comparable in both groups. Further studies using higher dose of dexmedetomidine are warranted

The primary aim of this study was to identify the rate of osteoarthritis in scaphoid fracture non-union. We also aimed to investigate whether the incidence of osteoarthritis correlates with the duration of non-union(interval), and to identify the variables that influence the outcome. We retrospectively reviewed 273 scaphoid fracture non-union presented between 2007 and 2016. Data included patient demographics, interval, fracture morphology, grade of osteoarthritis (Kellgren-Lawrence) and scaphoid non-union advanced collapse (SNAC), and overall health-related quality of life. Patients were divided into two groups (SNAC and Non-SNAC). Group differences were analysed using Mann-Whitney U test and association with Pearson's correlations. A two-sided p-value of <0.05 was considered significant. The scaphoid fracture non-union were confirmed on CT scans (n=243) and plain radiographs (n=35). The subjects were 32 females and 260 males with the mean age of 33.8 years (SD, 13.2). The average interval was 3.1 years (range, 0–45 years). Osteoarthritis occurred in 58% (n=161) of non-unions, and 42% (n=117) had no osteoarthritis. In overall, 38.5% (n=107) had SNAC-1, 9% (n=25) with SNAC-2, and 10.4% (n=29) presented with SNAC-3. The mean interval in the non-SNAC group was 1.2 years, and in SNAC 1,2, and 3 were 2.6, 6.8, and 11.1 years, respectively. The average summary index in SNAC and non- SNAC groups was 0.803 and 0.819, respectively. Our results also showed a significant correlation between advanced osteoarthritis and proximal fracture non-unions(P<0.05). We concluded that there is no clear correlation between the interval and the progression of osteoarthritis. SNAC was more likely to occur in fractures aged 2 years or older

Aim. Open fractures still have a high risk for fracture-related Infection (FRI). The optimal duration of perioperative antibiotic prophylaxis (PAP) for open fractures remains controversial due to heterogeneous guidelines and highly variable prophylactic regimens in clinical practice. In order to provide further evidence with which to support the selection of antibiotic duration for open fracture care, we performed a preclinical evaluation in a contaminated rabbit fracture model. Method. A complete humeral osteotomy in 18 rabbits was fixed with a 7-hole-LCP and inoculated with Staphylococcus aureus (2×106 colony forming units, CFU per inoculum). This inoculum was previously shown to result in a 100% infection rate in the absence of any antibiotic prophylaxis. Cefuroxime was administered intravenously in a weight adjusted dosage equivalent to human medicine (18.75 mg/kg) as a single shot only, for 24 hours (every 8 hours) and for 72 hours (every 8 hours) in separate groups of rabbits (n=6 per group). Infection rate per group was assessed after two weeks by quantitative bacteriological evaluation of soft tissue, bone and implants. Blood samples were taken from rabbits preoperatively and on days 3, 7 and 14 after surgery to measure white blood cell count (WBC) and C-reactive protein (CRP) levels. Results. Duration of PAP had a significant impact on the success of antibiotic prophylaxis. The single shot regimen completely failed to prevent infection. All samples (soft tissue, implant and bone) from this group displayed high numbers of bacteria. Additionally, abscesses were present in two of six rabbits. The 24-hour regimen showed a reduced infection rate (1 out of 6 rabbits infected), but only the 72-hour course was able to prevent FRI in all animals in our model. After an initial postoperative peak on day three, CRP levels then decreased to baseline (approx. 30 µg/ml) in the 24h-group and 72h-group, but remained significantly higher in the single shot group at day 7 and 14 (p<0.05). Conclusions. When contamination with high bacterial loads is likely (e.g. in an open fracture situation), a 72-hour course of intravenous cefuroxime appears to be superior in preventing FRI compared to a single shot or 24-hour antibiotic regimen. Acknowledgements. This work was funded by AOTrauma

Early prosthetic joint infections (PJI) are managed with debridement, implant retention and antibiotics (DAIR). Our aim was to evaluate risk factors for failure after stopping antibiotic treatment. From 1999 to 2013 early PJIs managed with DAIR were prospectively collected and retrospectively reviewed. The main variables potentially associated with outcome were gathered and the minimum follow-up was 2 years. Primary endpoint was implant removal or the need of reintroducing antibiotic treatment due to failure. A total of 143 patients met the inclusion criteria. The failure rate after a median (IQR) duration of oral antibiotic treatment of 69 (45–95) days was 11.8%. In 92 cases PJI was due to gram-positive (GP) microorganisms, in 21 due to gram-negatives (GN) and 30 had a polymicrobial infection. In GP infections, combination of rifampin with linezolid, cotrimoxazole or clindamycin was associated with a higher failure rate (27.8%, P=0.026) in comparison to patients receiving a combination of rifampin with levofloxacin, ciprofloxacin or amoxicillin (8.3%) or monotherapy with linezolid or cotrimoxazole (0%) (Figure 1). Among patients with a GN infection, the use of fluoroquinolones was associated with a lower failure rate (7.1% vs 37.5%, P=0.044). Duration of antibiotic treatment was not associated with failure. The only factor associated with failure was the oral antibiotic selection, but not the duration of treatment. Linezolid, cotrimoxazole and clindamycin but not levofloxacin serum concentrations are reduced by rifampin; a fact that could explain our findings. Further studies monitoring serum concentration could help to improve the efficacy of these antibiotics when combining with rifampin

Purpose. Handgrip dynamometry has previously been used to detect pre - operative malnutrition and predict the likelihood of post - operative complications. This study explored whether a relationship exists between pre-operative pinch and power grip strength and length of hospital stay in patients undergoing hip and knee arthroplasty. We investigated whether handgrip dynamometry could be used pre - operatively to identify patients at greater risk of longer inpatient stays. Methods. 164 patients (64 male, 100 female) due to undergo lower limb arthroplasty (83 Total Knee Replacement, 81 Total Hip Replacement) were assessed in pre - admission clinic. Average measurements of pinch grip and power grip were taken from each patient using the Jamar hydraulic dynamometer (Jamar, USA). Duration of each inpatient stay was recorded. Patients with painful or disabling conditions involving the upper limb were excluded. Other clinical variables such as age and ASA grade were investigated as potential confounders of the relationship of interest and adjusted for. Results. Average duration of hospital stay was 9.4 days. Average pinch grip was 6.3kg, average power grip 25.4 kg. Both average pinch grip strength (p = 0.001) and average power grip strength (p=0.04) had a significant negative correlation with duration of inpatient stay. Patients with a pinch grip strength less than 6.3kg remained in hospital 2 days longer on average. Patients with a power grip strength less than 15kg remained in hospital 1.6 days longer on average. Conclusions. This study demonstrated a clear relationship between pre - operative grip strength and length of hospital admission in these patients. This simple test may be beneficial pre - operatively in identifying those patients likely to require longer inpatient stays and therefore those who would benefit from early nutritional intervention and focussed physiotherapy. We believe this may effect significant cost reductions in the NHS

Background. Although thigh pain is an annoying problem after total hip arthroplasty (THA), little information has been known about its natural course. Methods. To determine the frequency, time of onset, and duration of thigh pain after cementless THA, we evaluated 240 patients (240 hips) who underwent primary THA because of femoral head osteonecrosis with the use of a single tapered stem. Results. Twenty-seven patients (11.3%) experienced thigh pain during the follow-up of 3–11 years(mean, 84 months). The pain developed 2–78 months (median, 25 months) after THA. The 75% of pain developed within 36 months. In 25 patients, the pain disappeared postoperatively 1 month-64 months (mean, 17.4 months), and 2 patients (7.4%, 2/27) had persistent thigh pain. There were no differences in the latest Harris Hip Score between the thigh pain group and no thigh pain group. Conclusion. Our results provided basic information about the natural history of thigh pain after cementless THA with a tapered stem design

Time at the surgical ‘coal-face’ has been reduced by introduction of the European Working Time Directive (EWTD) significantly impacting training opportunity. Our null hypothesis was that duration of surgery is significantly longer if a trainee were performing the operation despite supervision or level of trainee experience. Cemented hip hemiarthroplasty was chosen as our index procedure as complexity is largely comparable between cases. 461 patients were identified on the hospital trauma database. Data were augmented by information regarding level of surgeon, assistant and time of surgery from the hospital theatre database. There was no significant difference in registrar and consultant operative times, mean time 69 and 72 minutes respectively. SHOs were significantly slower (mean 80 minutes, p=0.0006). Junior (ST5 or less) registrars were significantly slower (mean 81minutes, p=0.0002) whereas senior registrars were not. Supervision level had no effect on duration of senior registrar operations but when junior registrars were consultant supervised they were not significantly slower (mean 75 minutes, p=0.09). Supervised operating therefore reduces time variability and should be promoted within a climate of training. Increase in mean operative time in registrars and SHOs is insignificant within a day's operating and is unlikely to lead to cancellations of cases

Introduction. Over 40-years the dominant form of implant fixation has been bone cement (PMMA). However the presence of circulating PMMA debris represents a 3rd-body wear mechanism for metal-on-polyethylene (MPE). Wear studies using PMMA slurries represent tests of clinical relevance (Table 1). Cup designs now use many varieties of highly-crosslinked polyethylene (HXPE) of improved wear resistance. However there appears to be no adverse wear studies of vitamin-E blended cups.1–4 The addition of vitamin E as an anti-oxidant is the currently preferred method to preserve mechanical properties and ageing resistance of HXPE. Therefore the present study examined the response of vitamin-E blended liners to PMMA abrasion combined with CoCr and ceramic heads. The hip simulator wear study was run in two phases to compare wear with, (i) clean lubricants and (ii) PMMA slurries. Methods. The vitamin-e blended polyethylene liners (HXe+) were provided by DJO Surgical (Austin, TX) with 40mm CoCr and ceramic femoral heads (Biolox-delta). Polyethylene liners were run in standard “Inverted” test. (Table 1) All cups were run in ‘clean’ serum lubricant for 6-million load cycles (6Mc)5 and in a debris slurry (PMMA: 5mg/ml concentration) for 2Mc.4 A commercial bone cement powder was used as “abrasive” (Biomet, Warsaw, IN). PMMA slurries were added at test intervals 6, 6.5, 7 and 7.5Mc.4 Wear was assessed gravimetrically and characterized by linear regression. Bearing roughness was analyzed by interferometry and SEM. Results. The acetabular cups showed low wear-rates to 6Mc duration with both ceramic and CoCr heads (Fig. 1). The debris slurries created much higher wear-rates, whereas control liners continued as before (Table 2). Discussion. This is the 1st study of vitamin-E blended polyethylene under 3rd-body wear conditions. With clean lubricant conditions, CPE combination wore approximately 50% less than MPE combination. Under abrasive lubricant conditions, CPE and MPE combinations wore at approximately same rate but more than an order of magnitude greater than the clean test phase. This was typical of such PMMA abrasion tests (Table 1). However there are no guidelines as to optimal choice of particulate type, morphology, dosage, frequency of injection or duration of test intervals (Table 1). The production of particulates in vivo is an unpredictable phenomenon and consequently laboratory simulation is fraught with uncertainties.6 On completion of the abrasive challenge (6–8Mc duration), our study will continue under clean conditions to 10Mc to define the important recovery phase of the vitamin-E blended polyethylene.3

High energy chest trauma resulting in flail chest injury is associated with increased rates of patient morbidity. Operative fixation of acute rib fractures is thought to reduce morbidity by reducing pain and improving chest mechanics enabling earlier ventilator weaning.

A variety of operative techniques have been described and we report on our unit's experience of acute rib fracture fixation. Over 18 months, 10 patients have undergone acute rib fracture fixation. Outcome measures included; patient demographics, time ventilated pre-operatively, time ventilated post-operatively and time spent on ITU/HDU post operatively.

The mean time from presentation to surgery was 5 days (range 2–12 days). The mean time ventilated post operatively was 2 days (range 1–4 days) and the mean number of days spent on ITU/HDU post-operatively was 6 days (range 2–11 days).

Our results appear positive in terms of time spent ventilated post-operatively but no conclusion can be drawn as we have no comparable non-operative group. We have however shown, that rib fracture fixation can be carried out successfully and safely in a trauma centre. Further evidence on rib fracture fixation is required from a large, multi-centre randomised controlled trial.

Controversy has existed for decades over the role of fretting-corrosion in modular CoCr heads used with stems of CoCr vs Ti6Al4V. Since retrieval data on taper performance remains scant, we report here an18-year survivorship of a Ti6Al4V: CoCr combination (APR design; Intermedics Inc). Unique to this study were the threaded profiles present on both stem and head tapers (Fig. 1).

This female patient was revised for pain, osteolysis and recurrent hip dislocation at 17 years, 10 months. A prior MPE hip replacement performed for her severely dysplastic right hip had lasted 11 years. At this 2nd revision, the 28 mm CoCr head was found dislocated posteriorly and superiorly. Metallosis was evident in the tissues. The polyethylene liner showed extensive rim damage on both anterior and posterior aspects. The neck of her APR Revision stem (Intermedics Inc) had worn through the polyethylene rim and impinged on the metal cage. The cage was found loose, the liner had disassociated, and the peri-trochanteric areas were compromised by massive osteolysis. The femoral stem and head were removed together without disassembly. The femoral stem and acetabular construct were replaced by an ARCOS revision system using 36 mm head with a Freedom cup (cemented to Max-Ti cage; Biomet Inc.).

The complete femoral neck and head were bi-valved assembled in horizontal plane for direct imaging by interferometry and SEM (Fig. 1a). After sectioning the head separated from the stem. Quantitative imaging used 1 to 5 regions with 6-replicate measurements per region and differentiation into contact and non-contact zones (Fig. 1b). Visual corrosion mapping (3) was recorded digitally in 4 anatomical views (Figs 1b–f).

The thread profile on contact zone inside the head (Fig. 2a) had a pitch of approximately 40 μm and a peak-to-valley depth of 4 μm overall (Fig. 2b profile section of thread: PV = 2 μm). The thread profile on stem trunnion (Fig. 3a) had a pitch of approximately 125 μm and a peak-to-valley depth of 3.5 μm overall (Fig. 2b profile section of thread: PV = 1 μm). Thus the stem trunnion thread was much coarser than the head. Overall corrosion grading was judged very mild. Overall we were satisfied that this Ti6Al4V: CoCr combination taper junction with threaded interfaces had performed very well for 18 years. Nevertheless, our visual grading was subject to opinion and thus unrewarding. The continuing project will quantify the contacting and non-contacting regions of head and stem (Fig. 1b).