A comparison of outcomes in morbidly obese, obese and non-obese patients undergoing primary total knee and total hip arthroplasty.

BACKGROUND: Obesity is a growing public health issue with the prevalence of morbid obesity, (Body Mass Index (BMI) ≥ 40 kg/m2) increasing. There is some evidence these patients have more peri- and post-operative complications and poorer outcomes when undergoing arthroplasty procedures. This audit aimed to determine and compare the outcomes of non-obese, obese and morbidly obese patients undergoing arthroplasty at our institution. METHOD: This was a retrospective audit of patients from our institution who had undergone total knee (TKA) or total hip arthroplasty (THA) in 2009. Data collected were: age, gender, BMI, length of stay (LOS), Oxford knee or hip score (OKS/OHS), satisfaction and complications up to two years post operation. Patients were divided into three groups: BMI < 30, BMI 30-40 and BMI > 40. Outcomes for each BMI group were compared. RESULTS: 1014 TKA and 906 THA operations were included. When compared to obese and non-obese patients, morbidly obese patients undergoing TKA had a mean LOS one day longer, a mean OKS four points lower and higher rates of postoperative problems, 37% vs. 21%. For THA patients there was no difference in LOS, OHS score was two points lower for each increasing BMI category and postoperative problems increase from 25% for non-obese to 31% for obese and 38% for morbidly obese patients. CONCLUSION: These results will be useful in informing obese patients of their potential outcomes following TKA or THA. These patients can then make a more informed choice before proceeding with arthroplasty.

Blood tests: One too many? Evaluating blood requesting guidance developed for acute patients admitted to trauma and orthopaedic units.

In a recently published report from the Academy of Medical Royal Colleges, around 20% of clinical practice which encompasses blood science investigations is considered wasteful. Blood tests including liver function tests (LFTs), C-reactive protein (CRP), coagulation screens, and international normalising ratios (INR) are frequently requested for patients who undergo emergency hospital admission. The paucity of guidance available for blood requesting in acute trauma and orthopaedic admissions can lead to inappropriate requesting practices and over investigation. Acute admissions over a period of one month were audited retrospectively for the frequency and clinical indications of requests for LFTs, coagulation screens/INR, and CRP. The total number of blood tests requested for the duration of the patient's admission was recorded. Initial auditing of 216 admissions in January 2014 demonstrated a striking amount of over-investigation. Clinical guidelines were developed with multidisciplinary expert input and implemented within the department. Re-audit of 233 admissions was carried out in September 2014. Total no. of LFTs requested: January 895, September 336 (-62.5%); coagulation screens/INR requested: January 307, September 210 (-31.6%); CRPs requested: January 894, September 317 (-64.5%). No. of blood requests per patient: January (M=4.81, SD 4.75), September (M=3.60, SD=4.70). Approximate combined total cost of LFT, coagulation/INR, CRP in January £2674.14 and September £1236.19 (-£1437.95, -53.77%). A large decrease was observed in admission requesting and subsequent monitoring (p<0.01) following the implementation. This both significantly reduced cost and venepuncture rates.

The use and efficacy of intra-operative stress tests in supination-external rotation IV ankle fracture fixation.

This study examines stress radiograph use in SER IV ankle fracture fixation; the efficacy of external rotation (ERST) and lateral hook (LHST) stress tests with incidence of subsequent fixation failure secondary to syndesmotic diastasis. 154 skeletally mature patients were admitted to our unit with ankle fractures in 12 months. 42 non-SER fractures and 32 SER fractures treated without ORIF were excluded, as were 14 which featured a syndesmotic screw in the primary ORIF. The remaining 66 SER IV fixations were included in the final sample (17 men, 49 women; median age 49 years). No stress test was performed in 51.5% of cases without a single subsequent failure in these fixations. ERST was the more commonly performed test (incidence 30.3%); negative predictive value (NPV) 0.95. Incidence of LHST was 18.2%; NPV 0.83. Both tests were performed in 6.1% of cases; NPV 0.75. The incidence of failure secondary to syndesmotic diastasis was 6.1% (4/66). Notably, there were no failures in the cases where no stress test was performed. Use of either or both external rotation and lateral hook stress tests resulted in failures to detect syndesmotic diastasis with consequent failure of fixation. This study suggests that syndesmotic injuries are not missed due to an absence of a stress test but that stress tests are not sufficiently sensitive or correctly interpreted. Clinical judgement in cases where syndesmotic injury is not present appears accurate. If syndesmotic injury is clinically suspected, apply caution and insert a syndesmotic screw rather than relying on stress test results.

Training benefits of computer navigated total knee arthroplasty.

BACKGROUND: Computer navigation aims to improve the surgical accuracy of total knee replacement by more reliably placing the cutting blocks in the optimum location in order to create a neutral mechanical axis. Aside from the obvious clinical benefit to the patient, we believe computer navigation has a valuable role as a training tool. The aim of this study is to demonstrate the effectiveness of computer navigation as a training tool in total knee arthroplasty. METHODS: We performed a training exercise using Sawbone plastic models to simulate four common sources of error in the saw technique; 1. cutting guide movement due to inadequate fixation, 2. the effect of using slotted or open cutting guides, 3. the effect of bending the saw blade, and 4. the effect of recutting on the accuracy of the intended resection. RESULTS: We found that bony resection errors resulted from; use of less than three pins to fix the cutting guide, use of open cutting guides, deliberate and inadvertent "hanging" or "lifting" of the saw on the cutting guide and recutting after moving the cutting guide. CONCLUSION: The immediate feedback provided by computer navigated TKA allows surgeons and trainee surgeons the opportunity to improve the accuracy of their technique and increase awareness of their individual sources of error in TKA. CLINICAL RELEVANCE: Used as a teaching tool, computer navigation can immediately identify errors in surgical technique and target subsequent training to minimise these errors. Training can be conducted whilst ensuring there is no detriment to patient safety.

Two cases of neurofibromatosis presenting with a foot deformity.

Two children presented with an isolated foot and ankle deformity. Examination in each suggested a plexiform neurofibroma although this diagnosis had not been considered before referral. Diagnosis of neurofibromatosis type 1 was confirmed by MRI scanning and on investigation both patients were proved to have widespread disease. One had a plexiform neurofibroma encasing the aorta and oesophagus. Both cases remain under observation and have not undergone surgery for their disease. Neurofibromatosis can present with isolated foot and ankle deformity and when such a diagnosis is suspected thorough investigation is important in a condition in which unsuspected widespread disease may exist.

Use of the mini C-arm for wrist fractures--establishing a diagnostic reference level.

The establishment of diagnostic reference levels (DRLs) for all typical radiological examinations became mandatory following the implementation of the Ionising Radiations (Medical Exposure) Regulations Act 2000. At present, there are no national dosage guidelines in the UK regarding use of fluoroscopy in orthopaedic trauma. The increasing popularity of the mini C-arm image intensifier amongst surgeons has led to concerns regarding use of ionizing radiation by personnel who have not been trained in radiation protection. It is therefore essential to have formal protocols for use of the mini C-arm to comply with the law and to maintain safe clinical practice. It is attempted to provide dose data for wrist fracture manipulations that may be used as a basis for setting a DRL for this procedure. Screening times were recorded for 80 wrist manipulations in a fracture clinic setting using a mini C-arm image intensifier. A DRL was set using the third quartile value for screening time. The median screening time for wrist fractures was 20 s with a range from 1 to 177 s. The third quartile value for screening time was 34 s. This value can be used as a provisional DRL for wrist fracture manipulations. The DRL is a quantitative guide for the optimisation of radiological protection. IR(ME)R 2000 states that if it is consistently exceeded by an individual operator or a piece of equipment, investigation and remedial action must be taken. We recommend that trauma units establish their own local DRLs for common procedures as made mandatory by legislation.