Aims

To examine incidence of complications associated with outpatient total hip arthroplasty (THA), and to see if medical comorbidities are associated with complications or extended length of stay.

We report the results of the use of the Long Gamma Nail in the treatment of complex proximal femoral fractures in our hospital. All patients at one hospital treated with the Long Gamma Nail were reviewed. Information collected included the age, sex, type of injury, fracture classification, intra-operative complications, post-operative complications, and survival of the implant and patient. One hundred nails were reviewed which were inserted in 97 patients. 70 patients were followed up for 1 month or more and their mean follow up was 8 months (range 3 months to 6 years). The mean age was 74 (range 16–98). Twenty were inserted into femurs with metastatic malignancy and four patients were victims of poly-trauma. The average length of the operation was 2 hours 22 minutes. Blood transfusion was required in 74% and on average was 2.5 units. There were 7 significant complications. Five patients underwent revision, 2 to Total Hip Arthroplasty after proximal screw migration and 2 patients required exchange nailing. There was one broken nail and two peri-prosthetic fractures at the tip of the nail. Success was defined as achievement of stability of fracture until union or death; this was achieved in 15% of cases. The mortality was 7% at 30 days and 17% at one year. One death was directly related to the nail and the rest due to medical co-morbidities. Complication rate fell with increasing experience in the unit. The training of surgeons had no detrimental effect on outcome. Complex proximal femoral fractures including pathological lesions, subtrochanteric fractures and pertrochanteric fractures with subtrochanteric extensions are difficult to treat, with all implants having high failure rates. The long gamma nail allows early weight bearing and seems effective in treating these difficult fractures. Furthermore the majority of these unstable fractures tend to occur in the very elderly with osteoporosis and other medical co-morbidity. Care should be taken to avoid malpositioning of the implant, as this was the major cause of failure and revision. The length of time surgery may take and the anticipated blood loss should not be underestimated especially when dealing with challenging fractures in frail and elderly patients or those with medical co-morbidity

Introduction. Post-operative gait abnormalities are recognized following total hip arthroplasty (THA). Despite global improvement in functional outcome, gait abnormality persists for a decade or more. In this study 3-dimensional gait analysis (3DGA) was performed using a portable system with Inertial Measurement Units (IMUs) to quantify this abnormality. Methods. The gait of 55 patients with monarthrodial hip arthrosis was measured pre-operatively and at one year post-surgery. Patients with medical co-morbidity or other conditions affecting their gait were excluded. Six IMUs were aligned at the level of the anterior superior iliac spines, mid-thigh and mid-leg. Data was analysed using proprietary software. Each patient underwent a conventional THA using a posterolateral approach. 92 healthy individuals were assessed for comparison. Results. Pre-operative movement in the sagittal plane of the ipsilateral hip (mean range 20.4) and the contra-lateral non-diseased hip (35.3 degrees) was reduced compared to the control group (40.5 degrees), (P<0.001). The pre-operative movement of both knees was reduced compared with normal (P<0.001). Pelvic movement on the ipsilateral side was increased. After one year ipsilateral hip movement significantly improved (Mean range 28.9 deg SD 6.6) but did not reach normal values (P<0.001). Movement measured in the contralateral hip was further reduced with a mean difference of −5.25 degrees (95% CI −8.06 to −2.43). Knee movement on both sides increased but not to normal values (p<0.001). There was increased coronal movement bilaterally at the thigh and calf one year after surgery. Discussion and Conclusion. Gait after routine THA does not return to normal. Unilateral hip pathology causes bilateral gait abnormality affecting the entire kinematic chain. This portable technology allows practical assessment of gait in the outpatient setting and will enable identification of key aspects of gait abnormality to target during rehabilitation following THA

Introduction. Improvements in function after THA can be evaluated using validated health outcome surveys but studies have shown that PROMs are unreliable in following the progress of individuals. Formal gait lab analysis is expensive, time consuming and fixed in terms of location. Inertial Measurement Units (IMUs) containing accelerometers and gyroscopes can determine aspects of gait kinematics in a portable package and can be used in the outpatient setting (Figure 1). In this study multiple metrics describing gait were evaluated pre- and post THA and comparisons made with the normal population. Methods. The gait of 55 patients with monarthrodial hip arthrosis was measured pre-operatively and at one year post-surgery. Patients with medical co-morbidity or other condition affecting their gait were excluded. Six IMUs aligned in the sagittal plane were attached at the level of the anterior superior iliac spines, mid-thigh and mid-shank. Data was analysed using proprietary software (Figure 2). Each patient underwent a conventional THA using a posterolateral approach. An identical test was performed one year after surgery. 92 healthy individuals with a normal observed gait were used as controls. Results. In the pre-operative test the range of movement in the sagittal plane of both the ipsilateral hip (mean range 20.4) and the contra-lateral non-diseased hip (35.3 degrees) was reduced compared to the control group (40.5 degrees), (P<0.001). The pre-operative range of motion of both knees was also reduced compared with normal (P<0.001). Pelvic movement on the ipsilateral side was increased. After one year the range of movement of the ipsilateral hip significantly improved (Mean range 28.9 deg SD 6.6) but did not attain normal values (P<0.001). Movement measured in the contralateral hip reduced further from its pre-operative value with a mean difference of −5.25 degrees (95% CI −8.06 to −2.43). Measurements of the symmetry of movement were increased. Knee movement on both sides increased but not to normal values (p<0.001). In contradistinction, there was bilateral increased coronal movement at the thigh and calf a year after surgery. Discussion and Conclusion. Gait after routine THA does not return to normal on the ipsilateral or contralateral side. Pathology in one hip causes bilateral gait abnormality that can be quantified by movement at the pelvis, hip, thigh and knee. The ability of a patient to walk normally after surgery will depend on many factors including details of the hip operation such as accurate recreation of the biomechanics of the joint and physical therapy regimens. Advances in technology now allow assessment of gait in large number of patients in the clinic setting and will better allow us to establish the important factors to improve patients gait and thereby potentially improve further satisfaction and PROMS scores. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Study Purpose: To investigate whether the use of reinfusion drains and post-operative autogenous blood transfusion reduces the rate of allogeneic blood transfusion after primary total knee replacement in our unit. Methods: A prospective audit was carried out over a 14-week period. Patients received either a reinfusion drain, a suction drain or no drain according to surgeon preference. Post-operative allogeneic blood transfusion criteria were based on clinical indication rather than an absolute haemoglobin level. Results:127 consecutive patients underwent total knee replacement during the study period. Patients were matched between the three groups for age, medical co-morbidity, DVT prophylaxis, and implant used. Conclusion: The use of reinfusion drains did not significantly reduce the requirement for post-operative allogeneic blood transfusion. This directly contrasts much of the published literature

Aims. To devise a simple clinical risk classification system for patients undergoing primary total knee arthroplasty (PTKR) to facilitate risk and cost estimation, and aid pre-operative planning. Methods. We retrospectively reviewed a series of consecutive PTKRs performed by the senior author. A classification system was devised to take account of principal risk factors in PTKR. Four groups were devised: 1) Non complex PTKR (CP0): no local or systemic complicating factors; 2) CPI: Locally complex: Severe or fixed deformity and/or bone loss, previous bony surgery or trauma, or ligamentous instability; 3) CPII Systemic complicating factors: Medical co-morbidity, steroid or immunosuppressant therapy, High BMI, (equivalent to ASA of III or more); 3) CPIII: Combination of local and systemic complicating factors (CPI+CPII). The patients were grouped accordingly and the following were compared: 1) length of stay, 2) post-operative complications, and 3) early post-discharge follow-up assessment. The complications were divided into local (wound problems, DVT, sepsis) and systemic (cardiopulmonary, metabolic, and systemic thromboembolic) complications. Results. The total number of patients was 119 (CP0=37,CPI=19,CPII=30,CPIII=33). Multiple regression analysis revealed: 1) no significant difference between complication rates in the CP0 and CPI groups, 2) 3-fold and 4-fold increase in the cumulative risk in the CPII and CPIII groups respectively (p<0.001), 3) significantly increased length of stay in the CPII and CPIII groups (p<0.001). Conclusion. The groups in this classification system correlate well with complication rates from surgery. As such this system has a role in stratifying patients for pre-operative planning and risk counselling. It is reproducible and can be used for larger patient groups via the National Joint Registry. Our findings also have implications for payment by results and fixed tariffs for PTKR, as the higher complication rates in the CPII and CPIII groups are likely to attract greater expense by hospitals in the course of these patients' treatment

Introduction: Dr Foster data presents mortality rate for fracture neck of femur in acute trusts. We assessed the accuracy of this data in an acute trust in England for a nine-month period. Methods: Fifty-seven patients (17.2%) died due to fracture NOF during our review period according to Dr Foster. Medical notes were retrospectively analysed in detail. There were 20 males with a mean age of 84.5yrs (64–100) and 37 females with a mean age of 85.7yrs (57–100). Data analysis included time and day of admission, admission ward, senior orthopaedic review, anaesthetic review, ASA grade, time to surgery, grade of anaesthetist and operating surgeon, type of anaesthesia, time of anaesthesia and surgery, type of surgery, post-op recovery and cause of death. Results: Seven patients died before their planned surgery due to extensive medical co-morbidity and 50 patients (15.1%) underwent surgery as planned. Thirty-one patients (9.4%) died under the care of the orthopaedic team and were considered by the assessors to be true death due to fracture neck of femur. Eleven patients (3.3%) died in the community after discharge home some several months later. Eight patients (2.4%) died under the care of the rehabilitation team, some months later, the majority from medical causes. The mean time to surgery was 2.7 days (0–13), which was mainly affected by weekend admissions. There were no records of the cause of death in 20 patients including all those that were discharged to the community. Admission time, ward and type and duration of anaesthesia had no effect on mortality rate. Conclusion: In our review Dr Foster overestimated true death rate due to fracture neck of femur. This trend is worrying as such indicators are linked to financial and performance targets for trusts. Accurate data presentation is therefore imperative and Dr Foster does not appear to deliver this

Introduction. Following National patient safety alert on cement use in hip fracture surgery, we investigated the incidence and pattern of 72 hours peri-operative mortality after hip fracture surgery in a District General Hospital. Methods. We reviewed all patients who had hip fracture surgery between 2005-April, 2010. We recorded demographic variables, type of fracture, implant used, medical co-morbidity, seniority of operating surgeon and anaesthetist, peri-operative haemodynamic status, time and cause of death. Results. Over a 64 month period 15 cases were identified. Peri-operative death (PAD) was 1% (15/1402). 4/15 patients died intra-operatively. PAD was highest following Exeter Trauma Stem (ETS) implantation (5/85, 6%) and nil following Bipolar arthroplasty, Austin-Moore arthroplasty (AMA) or Cannulated screw fixation. PAD following total hip arthroplasty was 4% (1/25), Thompson's hemi-arthroplasty 2% (3/191), and Dynamic Hip Screw fixation 1% (6/695). Overall mortality after cemented implant was 2%. ETS implantation led to significantly increased peri-operative mortality compared to AMA (p=0.004). Operations were performed by both trainees (12) and Consultants (3). Both trainees (9) and Consultants (6) anaesthetised the patients. None of the patients belonged to ASA I or II (ASA III 6 and IV 9). All patients had significant cardio-vascular or pulmonary co-morbidity (Ca Lung 2, pulmonary fibrosis 1, end stage COAD 1, AF 6). Cemented implant insertion was followed by immediate haemodynamic collapse and death in 4/15, intra-operative haemodynamic instability in 1/15 and peri-operative instability in 5/15. Post-mortem was performed in 5/15: 2/5 were Pulmonary Embolism (PE), 2/5 bronchopneumonia and 1/5 Myocardial infarction (MI). 4/15 had suspected MI and 1/15 suspected PE. Conclusion. There was 1% risk of peri-operative death after hip fracture surgery. This risk was increased following cemented hemiarthroplasty and highest after ETS implantation. Risk was exacerbated in patients with pre-existing cardiovascular morbidity and independent of the seniority of the surgeon or the anaesthetist

Objectives: To determine the effect of an Orthogeriatric team (OGT) upon patient management pre-operatively after its incorporation into a regional trauma centre of a district general hospital in the UK. Design: Prospective audit covering all patients admitted with a fractured hip for surgery one year before and one year after the establishment of an OGT. Method: A total of 288 fractured hips were operated on during February 2004 to February 2005. From February 2005 the OGT was created, consisting of a Staff Grade and 2 Senior House Officers (junior residents), assisted part-time by a consultant. Patients were medically managed and optimised for theatre; 301 patients underwent surgery in the 1st year from Feb 2005 to 2006. The data was collected prospectively from admission, and entered onto a database. Results: Before the set up of the OGT only one-quarter (25%) of patients were operated on within 24hours compared to almost one-half of patients (44%) under the care of the OGT. Of the patients waiting more than 24hours, delay while waiting for special tests was similar but there was a significant difference in the percentages of patients delayed due to lack of theatre time and poor medical condition. Only 5% of patients under the care of the OGT were delayed due to medical co-morbidity compared with 44% when solely under orthopaedic care. Conclusion: Focused high-quality medical input provided by a specialist Orthogeriatric team resulted in significantly reduced delays to theatre for patients admitted with a fractured hip. This is in the context of our hip fracture population becoming increasingly frail with increasing medical problems and continuing pressures on operating time. In the environment of financial constraint, this study confirms that reduction in time to theatre, effective, appropriate investigation and lower complication rates are likely offset the cost of the team. This may provide a model for other units

A review of total hip replacements (THR) performed in Palmerston North between 1991–2000 has identified a group of postoperative patients in whom recurrent dislocation has been previously deemed untreatable because of medical co-morbidity. From 1998 to 2001, 47 patients underwent THR utilizing a semi-constrained “Kasselt” cup to reduce the risk of dislocation. Indications for use of this cup were: Recurrent dislocation following primary or revision THR (3 or more dislocations) or perceived greater risk of recurrent dislocation eg. elderly, mental confusion, neurological compromise or fracture neck of femur. This paper presents the early results in these 47 patients (49 hips). Clinical records and radiographs of all hip replacement patients were retrospectively reviewed to identify the “Kasselt” group and telephone contact was made for permission to participate in the study. All living patients were sent a self-evaluation questionnaire and invitation to attend clinic for physical examination and radiographs of the hip joint. Twenty-one patients were recurrent dislocators and 24 were at risk patients. Out of 45 living patients 36 were physically examined between 6 and 36 months following surgery. All collected data was statistically analysed using StatWave software. Results: Forty-three of the 45 living patients (47 hips) had no dislocations following surgery. Two patients suffered further dislocation, both of whom were previously recurrent dislocators. One suffered a single dislocation postoperatively which was reduced closed and to date has not re-dislocated. The second continues to dislocate. The mean postoperative Harris Hip Score in the whole group is 79 (range 49–100). Early results reveal no dislocations in the “at risk” primary group

We examined the effect of age, gender, body mass index (BMI), medical co-morbidity as represented by the American Society of Anaesthesiologists (ASA) grade, social deprivation, nursing practice, surgical approach, length of incision, type of prosthesis and duration of surgery on length of stay after primary total hip arthroplasty (THA). Data was collected on 675 consecutive patients in a regional orthopaedic centre in South West England. The length of stay varied from 2 to 196 days and was heavily skewed. Data were therefore analysed by non parametric methods. To permit comparison of short with protracted length of stay, data were arbitrarily reduced to 2 groups comprising 2 to 14 days for short stays and 15 to 196 for long. These data were analysed by Chi-squared and Fisher’s exact test in univariate and by Logistic regression for multivariate analysis. The mean length of stay was 11.4 days, an over-estimate compared to the median length of stay of 8 days which more correctly reflects the skewed nature of the distribution. 81.5% of patients left hospital within 2 weeks, 13.6% within 2 and 4 and 4.9% after 4. On univariate analysis age above 80 years, age between 70 and 79 years, Body Mass Index > 35, ASA grades 3 and 4, transgluteal approaches, long incisions, cemented cups and prolonged operations were associated with longer stays. On multivariate analysis, age above 80, age between 70 and 80, ASA grades 3 and 4, prolonged operations and long incisions were highly significantly associated with hospital stay of over 2 weeks. This is the first study to record all the published variables associated with length of stay prospectively and to subject the data to multivariate analysis. Prolonged stay after THA is pre-determined by case mix but slick surgery through limited incisions may reduce the length of admission

Introduction and aims: Surgical decompression for lumbar stenosis entails a risk of iatrogenic instability. Consequently, laminectomy has been largely superseded by the more conservative procedure of fenestration, but the decompression may be compromised. We describe an additional technique of undercutting laminectomy, which conserves stability while maximising decompression, and the results are presented. Method: Forty-nine patients with lumbar spinal stenosis were treated by fenestration, medial facetectomy and removal with curved osteotomes of the ventral aspect of the lamina superior to the involved facets together with the attached ligamentum flavum. The results were assessed at a mean follow-up period of three years and four months using walking distance and a pain analogue scale as outcome measures, and surgical complications were recorded. The radiological results were assessed in 25 patients by measurement on MRI scan of the spinal canal cross-sectional area pre- and post-operatively. Results: Ten patients had undercutting laminectomy at one level, 19 at two levels, 14 at three levels and four at four levels. Medical co-morbidity was present in most patients; 11 were ASA 1, 25 ASA2 and 11 ASA 3. Pre-operatively, all patients reported leg pain or numbness and 20 patients reported back pain. All but one had limited walking distance, the mean being 564 metres (range 5m–8000m). Post-operatively the mean pain score was 3.3 and the mean walking distance 762 metres. Forty-one patients said they felt the operation had been worthwhile and six said they did not. Surgical complications occurred in five patients, consisting of dural tear in four patients (repaired with no sequelae) and a wound haematoma requiring drainage in one patient. The mean spinal canal cross-sectional area at the level of maximal stenosis pre-operatively was 28mm. 2. and postoperatively was 75mm. 2. , giving a mean increase of 133%. No patients had any evidence of iatrogenic instability as judged by the development of degenerative spondylolisthesis or scoliosis. Conclusion: The technique described achieves excellent decompression of the stenotic lumbar canal as measured radiologically, while largely preserving the facet joints. In relation to published reports on fenestration and medial facetectomy alone, the clinical results are at least as good

INTRODUCTION. Revision knee arthroplasty is increasing and in 2010 constituted 6% of knee replacements done in the UK according to the National Joint Registry. 1. Infection was the 2nd most common cause accounting for 23% of the revision burden. 1. Two-stage revisions are considered the gold standard with success rates from 80–100%. 2. Single-stage revisions are becoming increasingly popular at certain centers with reported benefits of reduced “down-time” for the patient and a decreased financial burden. OBJECTIVES. The senior author (DSB) has been performing single-stage revisions for infections for over 10 years. We were interested in seeing the success rate for this method and possibly identify factors that would portend a poorer result. METHODS. We performed a retrospective review of all single-stage revisions performed at our hospital by the senior author (DSB) from January 2001 to December 2010. In total, 340 revision knee arthroplasties were performed. Of these, 13 (4%) single-stage revisions for infections were identified. The case records of these cases were reviewed and details of the revision as well as medical co-morbidities were assessed to see if any of these factors correlated to a poor outcome. In all, there were 8 women: 5 men with a mean age of 70.9 years (range 49–80 years). 1 case was lost to follow-up and 2 died from unrelated conditions. The mean duration of follow-up for the remaining 10 patients was 4.9 years (range from 1.5 to 7 years). RESULTS. All patients presented with knee pain along with swelling (30%), stiffness (30%), instability (8%). 2 patients had a chronic discharging sinus. Most patients (92%) had at least 1 medical co-morbidity (e.g. steroid use, diabetes, malignancy, Crohn's disease). The mean time from index surgery to revision was 3.5 years (range 1 to 9 years). The causative microbe identified prior to surgery was MRSA (15%), MSSA (30%), coagulase-negative Staphylococcus (30%), Streptococcus Gp D (8%) and polymicrobial growth (MSSA with Pseudomonas) (8%). In 3 cases, no microbe was identified. Intraoperative findings were extensive scarring of the soft tissue in all cases with single component loosening in 30% and both component loosening in 15%. Post-operative complications included 1 case of cellulitis, 1 case of chronic regional pain syndrome and 1 case of hemarthrosis. Most cases had excellent ROM at their last follow-up. The final surgical outcome of the 10 patients at final follow-up were successful infection eradication in 9 (90%) and 1 failure (10%) requiring repeat 2-stage revision. This failure was the only case with a positive polymicrobial culture prior to his surgery growing MSSA with Pseudomonas. Cases in which we failed to identify the causative organism prior to surgery did not appear to impact on the success rate. CONCLUSION. We submit that a high success rate can be achieved using single-stage revision along with the potential for improved patient functional outcome due to a lack of “down-time” during the interval of the 2-stage revisions. We, however, cannot advocate this to be undertaken by all surgeons as we still accept that the gold standard remains the 2-stage revision

Aims

Following the resection of an extensive amount of bone in the treatment of a tumour, the residual segment may be insufficient to accept a standard length intramedullary cemented stem. Short-stemmed endoprostheses conceivably have an increased risk of aseptic loosening. Extra-cortical plates have been added to minimise this risk by supplementing fixation. The aim of this study was to investigate the survivorship of short-stemmed endoprostheses and extra-cortical plates.

We have investigated how medical postponement, the time to surgery and the correction of medical abnormalities, according to McLaughlin criteria, before operation affected peri-operative mortality after fracture of the hip. From February to December 2007, in addition to core data, the Scottish Hip Fracture Audit collected information relating to surgical delay. Data were available for 4284 patients which allowed 30-day survival analysis to be performed. Multivariable logistic regression models were used to control for differences in case-mix.

Patients with major clinical abnormalities were more likely to have a postponement and had a lower unadjusted 30-day survival. The time to operation and postponement were not associated with higher mortality after adjustment for case-mix. Correction of major clinical abnormalities before surgery improved the adjusted survival, but this improvement was not significant (p = 0.10). Postponement without correction of a medical abnormality before surgery was associated with a significantly lower (p = 0.006) 30-day adjusted survival. The possible benefits of postponement need to be weighed against prolonged discomfort for the patient and the possibility of the development of other complications.

This review examines the future of total hip arthroplasty, aiming to avoid past mistakes

We investigated the relationship between a number of patient and management variables and mortality after surgery for fracture of the hip. Data relating to 18 817 patients were obtained from the Scottish Hip Fracture Audit database. We divided variables into two categories, depending on whether they were case-mix (age; gender; fracture type; pre-fracture residence; pre-fracture mobility and ASA scores) or management variables (time from fracture to surgery; time from admission to surgery; grade of surgical and anaesthetic staff undertaking the procedure and anaesthetic technique).

Multivariate logistic regression analysis showed that all case-mix variables were strongly associated with post-operative mortality, even when controlling for the effects of the remaining variables. Inclusion of the management variables into the case-mix base regression model provided no significant improvement to the model. Patient case-mix variables have the most significant effect on post-operative mortality and unfortunately such variables cannot be modified by pre-operative medical interventions.

We report gender differences in the epidemiology and outcome after hip fracture from the Scottish Hip Fracture Audit, with data on admission and at 120 days follow-up from 22 orthopaedic units across the country between 1998 and 2005. Outcome measures included early mortality, length of hospital stay, 120-day residence and mobility. A multivariate logistic regression model compared outcomes between genders. The study comprised 25 649 patients of whom 5674 (22%) were men and 19 975 (78%) were women. The men were in poorer pre-operative health, despite being younger at presentation (mean 77 years (60 to 101) vs 81 years (50 to 106)). Pre-fracture residence and mobility were similar between genders.

Multivariate analysis indicated that the men were less likely to return to their home or mobilise independently at the 120-day follow-up. Mortality at 30 and 120 days was higher for men, even after differences in case-mix variables between genders were considered.

The results of 41 consecutive total knee replacements performed on morbidly obese patients with a body mass index > 40 kg/m², were compared with a matched group of 41 similar procedures carried out in non-obese patients (body mass index < 30 kg/m²). The groups were matched for age, gender, diagnosis, type of prosthesis, laterality and pre-operative Knee Society Score. We prospectively followed up the patients for a mean of 38.5 months (6 to 66). No patients were lost to follow-up. At less than four years after operation, the results were worse in the morbidly obese group compared with the non-obese, as demonstrated by inferior Knee Society Scores (mean knee score 85.7 and 90.5 respectively, p = 0.08; mean function score 75.6 and 83.4, p = 0.01), a higher incidence of radiolucent lines on post-operative radiographs (29% and 7%, respectively, p = 0.02), a higher rate of complications (32% and 0%, respectively, p = 0.001) and inferior survivorship using revision and pain as end-points (72.3% and 97.6%, respectively, p = 0.02).

Patients with a body mass index > 40 kg/m² should be advised to lose weight prior to total knee replacement and to maintain weight reduction. They should also be counselled regarding the inferior results which may occur if they do not lose weight before surgery.