Carlos A. Wigderowitz

Continuous interscalene infusion and single injection using levobupivacaine for analgesia after surgery of the shoulder: A DOUBLE-BLIND, RANDOMISED CONTROLLED TRIAL

We performed a double-blind, randomised controlled trial to assess the effectiveness of a continuous-infusion brachial plexus block with levobupivacaine compared with that of a standard single injection for the management of post-operative pain after surgery on the shoulder. Eight patients were randomised to receive a pre-operative brachial plexus block using 30 ml of levobupivacaine 0.5% with adrenaline 1:200 000 followed by insertion of a 20-gauge polyamide catheter. This was connected to a disposable elastometric pump, set immediately after surgery to administer a continuous flow of levobupivacaine 0.25% at a rate of 5 ml per hour. The other eight patients were randomised to receive only the initial injection of 30 ml. The study was double-blinded with the aid of sham catheters and clamped pumps. All patients were given regular paracetamol and were prescribed morphine through a patient-controlled analgesia pump. Motor and sensory block assessments, visual analogue scale pain scores and consumption of morphine were recorded after the operation and then at 6, 12 and 24 hours after administration of the block. Satisfactory motor and sensory block was achieved in all patients. The mean visual analogue scale pain score at 12 hours and consumption of morphine at 24 hours after injection were significantly lower (p < 0.05) in the continuous-infusion group. This group also took longer to request their first additional analgesia and reported a significantly higher overall level of satisfaction. Our study has shown that continuous interscalene infusion of levobupivacaine is an effective method of post-operative analgesia after major surgery of the shoulder.

Computerised measurement of tibiofemoral alignment

Tibiofemoral alignment has a direct correlation with the survival of total knee arthroplasty. Traditionally, it has been measured using a goniometer on radiographs. We describe new software which measures this alignment on scanned radiographs by automatically detecting bones in the image. Two surgeons used conventional methods and two clerical officers used the computerised routine to assess 58 radiographs of the knee on two occasions. There were no significant differences between any of the paired comparisons. The largest mean difference detected was 1.19 degrees. Across all comparisons, the mean correlation was 0.755. A standardised routine for measuring tibiofemoral alignment was the greatest factor in reducing error in our study. These results show that non-medical staff can reliably use the software to measure tibiofemoral alignment. It has the potential to measure all the parameters recommended by the Knee Society.

Prediction of bone strength from cancellous structure of the distal radius: can we improve on DXA?

Abstract: Recent studies show that structural parameters of bone, obtained from computerized image analysis of radiographs, can improve the noninvasive determination of bone strength when used in conjunction with bone density measurements. The present study was designed to assess the ability of image features alone to predict the mechanical characteristics of bones. A multifactorial model was used to incorporate simultaneously a number of characteristics of the image, including periodicity and spatial orientation of the trabeculae. Fifteen pairs (29 specimens) of unembalmed human distal radii were used. The cancellous bone structure was determined using computerized spectral analysis of their radiographic images and the bones were tested to failure under compression. Multilayered perceptron neural networks were used to integrate the various image parameters reflecting the periodicity and the spatial distribution of the trabeculae and to predict the mechanical strength of the specimens. The correlation between each of the isolated image parameters and bone strength was generally significant, but weak. The values of mechanical parameters predicted by the neural networks, however, had a very high correlation with those observed, namely 0.91 for the load at fracture and 0.93 for the ultimate stress. Both these correlations were superior to those obtained with dual-energy X-ray absorptiometry and with the cross-sectional area from CT scans: 0.87 and 0.49 respectively. Our observation suggests that image parameters can provide a powerful noninvasive predictor of bone strength. The simultaneous use of various parameters substantially improved the performance of the system. The multifactorial architecture applied is nonlinear and possibly more effective than traditional multicorrelation methods. Further, this system has the potential to incorporate other non-image parameters, such as age and bone density itself, with a view to improving the assessment of the risk of fracture for individual patients.

Efficacy of low-level laser therapy applied at acupuncture points in knee osteoarthritis: a randomised double-blind comparative trial ☆

OBJECTIVE To evaluate the efficacy of low-level laser therapy (LLLT) applied to acupuncture points on the knee joint in combination with exercise and advice in patients with knee osteoarthritis. DESIGN Randomised, double-blind, comparative clinical trial. PARTICIPANTS Forty-nine patients with knee osteoarthritis were assigned at random into two groups: active laser group (n=26) and placebo laser group (n=23). INTERVENTION Using a gallium aluminium arsenide laser device, patients received either active or placebo LLLT at five acupuncture points on the affected knee during nine sessions. OUTCOME MEASURES Patients were assessed using a visual analogue scale (VAS) and the Saudi Knee Function Scale (SKFS) at baseline, the fifth treatment session, the last treatment session, 6 weeks post intervention and 6 months post intervention. RESULTS VAS scores showed a significant improvement in the active laser group compared with the placebo laser group at 6 weeks post intervention [mean difference -1.3, 95% confidence interval (CI) of the difference -2.4 to -0.3; P=0.014] and 6 months post intervention (mean difference -1.8, 95% CI of the difference -3.0 to -0.7; P=0.003) using the independent samples test. SKFS scores also showed a significant improvement in the active laser group compared with the placebo laser group at the last treatment session (median difference -15, 95% CI of the difference -27 to -2; P=0.035) and 6 months post intervention (median difference -21, 95% CI of the difference -34 to -7; P=0.006) using the Mann-Whitney U test. CONCLUSIONS The results demonstrate that short-term application of LLLT to specific acupuncture points in association with exercise and advice is effective in reducing pain and improving quality of life in patients with knee osteoarthritis.

Determination of the EC50 of levobupivacaine for femoral and sciatic perineural infusion after total knee arthroplasty

BACKGROUND Infusion of local anaesthetic through femoral and sciatic catheters is an accepted method of providing pain relief after knee arthroplasty. However, the minimum effective concentration of perineural local anaesthetics is not known. METHODS Twenty-four patients received femoral and sciatic perineural infusions of levobupivacaine in order to prevent pain relief after total knee arthroplasty. The primary endpoint of the study was patient request for analgesic rescue for anterior or posterior knee pain within the first 36 h of perineural infusion. Treatment was determined by the method of sequential allocation, with a dosing interval of 0.002% w/v. RESULTS Thirteen patients did not require rescue analgesia for anterior knee pain and 16 patients did not require rescue analgesia for posterior knee pain. Median duration of failed blocks until rescue analgesia was 25 h (24-27 h) for the femoral block and 27 h (24-29 h) for the sciatic block. The minimum concentration at which patients did not require rescue analgesia was 0.024% for the femoral nerve and 0.014% for the sciatic nerve. Comparison of EC(50) showed that local anaesthetic requirements were significantly (P=0.03) higher by a factor of 1.25 (95% CI 1.03-1.55) for the femoral compared with the sciatic nerve. CONCLUSIONS The EC(50) for femoral perineural infusion is greater than the EC(50) for sciatic perineural infusion.

Patients and the Internet: A demographic study of a cohort of orthopaedic out-patients

The Internet is a rich source of medical information but relatively few studies have evaluated its use by patients who seek medical information. The purpose of this study is to assess the demographics of Internet access and attitudes towards the Internet in a cohort of orthopaedic out-patients. Four hundred and three patients attending the orthopaedic outpatient fracture clinic completed a questionnaire consisting of six divisions including personal information, facility to access the Internet and their attitudes towards the information retrieved. Fifty per cent of the patients accessed the Internet, either from home or office and the maximum usage being in the younger age group. Twenty-nine per cent of the patients were aware of the medical information available through the Internet. 19% patients would like to have a consultation through the Internet, the maximum being in the middle-aged group. 70% of those patients who accessed the medical information reported that the Internet information was different than that obtained at consultation with the doctor at the out-patient clinic. This study reveals that the Internet use by patients is still limited. If an increased percentage of medical conditions is to be addressed through the Internet, involving patient information, on-line consultations, prescriptions and referrals, then a substantial amount of patient education and training is required

A three-dimensional analysis of humeral head retroversion

INTRODUCTION The anatomic neck of the humerus is used as a reference for the osteotomy in shoulder arthroplasty. Resection along the anterior portion of the cartilage/metaphyseal border is assumed to remove a cap of a sphere that can accurately be replaced with a spherical prosthetic implant oriented precisely to the original articular surface. The aim of this study was to determine the variability in retroversion of the cartilage/metaphyseal interface in the axial plane. METHODS Surface topography data for 24 arms from deceased donors were collected by using a hand-held digitizer and a surface laser scanner. Data were combined into the same coordinate system and graphically presented. The humeral head was divided into 6 sections in the axial plane and the retroversion angle measured at each level with reference to the transepicondylar axis at the elbow. RESULTS The mean retroversion of the humeral head at the midpoint between the superior and inferior margins was 18.6°. The angle increased as the position of the measurement moved superiorly to 22.5°. In contrast, the retroversion angle reduced as the position of measurement moved more inferiorly to 14.3°. DISCUSSION The results suggest that the cartilage/metaphyseal interface is not circular encompassing a spherical cap of a sphere. Furthermore, there appears to be a clockwise torsion of the cartilage/metaphyseal interface about the transverse axis from its medial to lateral aspect. CONCLUSION The cartilage/metaphyseal interface shows a degree of variability that makes it an unreliable landmark to perform an osteotomy when the anterior aspect of the interface is used.

Learning Active Shape Models for Bifurcating Contours

Statistical shape models are often learned from examples based on landmark correspondences between annotated examples. A method is proposed for learning such models from contours with inconsistent bifurcations and loops. Automatic segmentation of tibial and femoral contours in knee X-ray images is investigated as a step towards reliable, quantitative radiographic analysis of osteoarthritis for diagnosis and assessment of progression. Results are presented using various features, the Mahalanobis distance, distance weighted K-nearest neighbours, and two relevance vector machine-based methods as quality of fit measure

Peri-operative renal morbidity secondary to gentamicin and flucloxacillin chemoprophylaxis for hip and knee arthroplasty

Introduction This retrospective cohort study uses serum creatinine levels to assess the effect of gentamicin and flucloxacillin on renal function in hip and knee arthroplasty patients. Methods Serum creatinine levels were recorded pre-operatively and at two points post-operatively (sample 1 and sample 2) for all patients undergoing hip and knee arthroplasty. Either cefuroxime, or gentamicin and flucloxacillin were used for chemoprophylaxis. The Risk, Injury, Failure, Loss, End Stage classification was used to assess renal injury. Results The differences in mean percentage change between the two groups were 5.86% (p = 0.077) and 11.34% (p = 0.030) at sample 1 and sample 2, respectively. Two patients (1.62%) receiving cefuroxime were exposed to renal risk or worse at some point. A total of nine patients (6.04%) receiving flucloxacillin and gentamicin were exposed to renal risk. Of these, three (2.01%) sustained renal injury and two (1.34%) sustained renal failure. The risk of being exposed to renal risk was 3.75 times greater for the gentamicin and flucloxacillin group. The risks of sustaining a significant deterioration of renal function were 1.9 and 17 times greater for the gentamicin and flucloxacillin group at the first and second post-operative samples, respectively. Discussion Flucloxacillin and gentamicin significantly worsens renal function post-operatively compared with cefuroxime.

Prescribing a website.

Aim: To assess the value of directing the attention of patients to sources of medical information on the internet. Design: Prospective qualitative study in an orthopaedic outpatient clinic. Participants: 253 patients agreed to complete electronic questionnaires before and after reviewing information relevant to their conditions on the internet. Patients were allocated randomly into two groups; one group was given indications of general sites and the other recommended specific non-commercial sites. Completed questionnaires were received from 44 patients. Results: 95% of the patients found the internet information easy to understand and 84% said that it was helpful for coping. 86% of the patients were satisfied that their current treatment was appropriate in the light of what they had learned from the internet. Ten patients out of the 36 who expressed a view thought that the internet information contradicted that provided by the doctor. Despite these results most patients still said that the doctor represented the best source of patient education. Conclusions: Increasing numbers of patients are familiar with the internet. Most of our patients felt that the internet was, on balance, helpful in providing information. The main difficulties with the internet are the sheer volume of information, the potential for misleading and the danger of misunderstanding. We feel that there is a real place for the specific prescription of an internet site by a clinician who has personally reviewed it to a patient thought to be able to benefit from it.