The Diagnostic Utility of Serum Metal Ion Markers for High-Grade Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesions (ALVALs) in Revision Hip and Knee Arthroplasty: An International Multicenter Study

BACKGROUND

Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) are typically described in the context of metal-on-metal (MoM) hip bearings. This study explores the diagnostic utility of preoperative serum cobalt and chromium ion levels in determining the histological grade of ALVAL in revision hip and knee arthroplasty.

METHODS

This was a multicenter retrospective review of 26 hips and 13 knees assessing the correlation between preoperative ion levels (mg/L (ppb)) and the histological grade of ALVAL from intraoperative specimens. The diagnostic ability of preoperative serum cobalt and chromium levels to determine high-grade ALVAL was assessed using a receiver operating characteristic (ROC) curve.

RESULTS

In the knee cohort, there was a higher serum cobalt level in high-grade ALVAL cases (10.2 mg/L (ppb) versus 3.1 mg/L (ppb)) (P = .0002). The Area Under the Curve (AUC) was 1.00 (95% confidence interval (CI) 1.00 to 1.00). There was a higher serum chromium level in high-grade ALVAL cases (12.25 mg/L (ppb) versus 7.77 mg/L (ppb)) (P = .0002). The AUC was 0.806 (95% CI 0.555 to 1.00). In the hip cohort, there was a higher serum cobalt level in high-grade ALVAL cases (333.5 mg/L (ppb) versus 119.9 mg/L (ppb)) (P = .0831). The AUC was 0.619 (95% CI 0.388 to 0.849). There was a higher serum chromium level in high-grade ALVAL cases (186.4 mg/L (ppb) versus 79.3 mg/L (ppb)) (P = .183). The AUC was 0.595 (95% CI 0.365 to 0.824).

CONCLUSIONS

Histologically, high-grade ALVAL has significantly higher preoperative serum cobalt and chromium ion levels in revision TKA. Preoperative serum ion levels have excellent diagnostic utility in revision TKA. Cobalt levels in revision THA have a fair diagnostic ability and chromium levels had a poor diagnostic ability.

Identification of protective and 'at risk' HLA genotypes for the development of pseudotumours around metal-on-metal hip resurfacings

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. 'Controls' were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size. Using a previously-reported ALVAL classification, the majority of pseudotumour-positive caseswere found to have intermediate-grade group 2 (n = 10; 63%) or group 3 (n = 4; 25%) histological findings. Two further patients (13%) had high-grade group 4 lesions. HLA-DQB1*05:03:01 (p = 0.0676) and HLA-DRB1*14:54:01 (p = 0.0676) alleles were significantly associated with a higher risk of pseudotumour formation, while HLA-DQA1*03:01:01 (p = 0.0240), HLA-DRB1*04:04:01 (p = 0.0453), HLA-C*01:02:01 (p = 0.0453), and HLA-B*27:05:02 (p = 0.0855) were noted to confer risk reduction. These findings confirm the association between specific HLA genotypes and the risk of pseudotumour development around MoM hip resurfacings. Specifically, the two 'at risk' alleles (DQB1*05:03:01 and DRB1*14:54:01) may hold clinical value in preoperative screening and prospective surgical decision-making.

Tourniquet use during primary total knee arthroplasty-a survey of Irish orthopaedic surgeons in 2022

BACKGROUND

Tourniquet use during primary total knee arthroplasty is a debated topic in the literature with no consensus on its optimal use.

AIM

To analyse current tourniquet practice amongst Irish orthopaedic surgeons performing primary total knee arthroplasty surgery. To evaluate if there has been a shift in practice in recent years and to explore potential reasons behind this.

METHODS

An eleven-question online survey was developed using the online platform SurveyMonkey. This was distributed by email to Irish orthopaedic surgeons via the Irish Institute of Trauma and Orthopaedic Surgery.

RESULTS

Fifty responses were included in the final analysis of this study. Eighteen (36%) respondents reported changing their tourniquet use in the past 5 years. Thirty-one (62%) respondents reported inflating the tourniquet for the entire case, with the remaining never applying a tourniquet (n = 6, 12%), applying a tourniquet but not routinely inflating it (n = 3, 6%), or inflating the tourniquet only during cementation (n = 5, 10%). The number of years of experience as a consultant appeared to impact tourniquet use in a bimodal pattern.

CONCLUSION

While the majority of Irish orthopaedic surgeons in this survey inflate a tourniquet for the entire surgical procedure, there is a definite shift towards reduced tourniquet use compared to previous Irish, UK, and American surveys.

Obesity trends over 10 years in primary hip and knee arthroplasty-a study of 12,000 patients

OBJECTIVES/AIMS

Obesity and its increasing prevalence are global public health concerns. Following joint replacement, there is evidence to support that obese patients are more likely to suffer complications. We examined 10-year trends in BMI of the primary total hip and total knee replacement cohorts in our institution to discern whether the BMI of these patients has changed over time.

METHODS

We examined BMI data of patients who underwent primary hip and knee arthroplasty from our institutional database from January 1, 2010 to December 31, 2019 (n = 12,169). We analysed trends in BMI over this period with respect to (i) surgical procedure, (ii) gender, and (iii) age categories.

RESULTS

The overall number of surgical procedures increased over the study period which meant more obese patients underwent surgery over time. Average BMI did not change significantly over time; however, there was a statistically significant increase in BMI in females aged < 45 in both arthroplasty groups.

CONCLUSION

The average BMI of patients undergoing primary hip and knee arthroplasty in our high-volume tertiary orthopaedic centre has remained relatively unchanged over the past 10 years; however, our local service is caring for a greater number of overweight/obese patients due to the increase in overall volume. This will have significant implications on health care expenditure and infrastructure going forward which further emphasises the importance of ongoing national obesity prevention strategies. The increase in BMI seen in females aged < 45 may mark an impending era of obese younger patients with end-stage osteoarthritis.

Third and fourth generation ceramic-on-ceramic total hip arthroplasty at a minimum of ten years

BACKGROUND

Ceramic on Ceramic bearings in Total Hip Arthroplasty (THA) afford a low friction coefficient, low wear rates and extreme hardness. Significant complications include hip squeak, ceramic fracture and poor polyethylene performance in revision procedures due to imbedding of abrasive microscopic ceramic fragments. We report on the results of this bearing at a minimum of 10 years.

METHODS

A single-centre retrospective review of 449 THAs was performed. Primary outcome measures included aseptic revision and all-cause revision rates at a minimum of 10 years post operatively. Evaluation of functionality was performed with WOMAC and SF-36 scores which were performed pre-operatively and at intervals of 6 months, one year, 2 years, 5 years and 10 years post operatively.

RESULTS

There was a 6.2% (n = 28) all-cause and 5.3% (n = 24) aseptic revision rate for ceramic on ceramic total hip arthroplasty at minimum of 10 years with a mean time to revision 4.8 years (range 2 months-11.6 years). Notably, there were 2 revisions for ceramic head fracture, one for ceramic liner fracture, 3 for aseptic loosening and 3 revisions for squeaking. Pain of unknown origin was the most common reason for revision. There was an improvement in postoperative WOMAC scores from a mean of 59.8 (range 15-95) pre-operatively to a mean of 15.6 (range 0-78) at 10 years.

CONCLUSION

This study showed good functional outcomes but high revision rates for CoC THA at a minimum of 10 years. Our rates of ceramic fracture were consistent with other studies.

Outcomes of the Exeter V40 cemented femoral stem at a minimum of ten years in a non-designer centre

Aims

The Exeter V40 cemented femoral stem was first introduced in 2000. The largest single-centre analysis of this implant to date was published in 2018 by Westerman et al. Excellent results were reported at a minimum of ten years for the first 540 cases performed at the designer centre in the Exeter NHS Trust, with stem survivorship of 96.8%. The aim of this current study is to report long-term outcomes and survivorship for the Exeter V40 stem in a non-designer centre.

Methods

All patients undergoing primary total hip arthroplasty using the Exeter V40 femoral stem between 1 January 2005 and 31 January 2010 were eligible for inclusion. Data were collected prospectively, with routine follow-up at six to 12 months, two years, five years, and ten years. Functional outcomes were assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Outcome measures included data on all components in situ beyond ten years, death occurring within ten years with components in situ, and all-cause revision surgery.

Results

A total of 829 stems in 745 patients were included in the dataset; 155 patients (20.8%) died within ten years, and of the remaining 664 stems, 648 stems (97.6%) remained in situ beyond ten years. For the 21 patients (2.5%) undergoing revision surgery, 16 femoral stems (1.9%) were revised and 18 acetabular components (2.2%) were revised. Indications for revision in order of decreasing frequency were infection (n = 6), pain (n = 6), aseptic component loosening (n = 3), periprosthetic fracture (n = 3), recurrent dislocation (n = 2), and noise production (ceramic-on-ceramic squeak) (n = 1). One patient was revised for aseptic stem loosening. The mean preoperative WOMAC score was 61 (SD 15.9) with a mean postoperative score of 20.4 (SD 19.3) (n = 732; 88.3%).

Conclusion

The Exeter V40 cemented femoral stem demonstrates excellent functional outcomes and survival when used in a high volume non-designer centre. Outcomes are comparable to those of its serially validated predecessor, the Exeter Universal stem.

Cite this article: Bone Jt Open 2020;1-12:743–748.

Custom solution for personal protective equipment (PPE) in the orthopaedic setting: retrofitting Stryker Flyte T5 PPE system

The coronavirus disease 2019 pandemic has meant that there is growing pressure on hospital resources, not least the availability of appropriate personal protective equipment (PPE), particularly face masks and respirator masks. Within the field of orthopaedic surgery, it is a common sight to see surgeons wearing ‘space suits’ (SSs) which comprise a helmet, hood and surgical gown.

In this study, the authors made modifications to two different SS systems to incorporate a high-efficiency particulate air (HEPA) filter into the fan inlet to assess their potential as re-usable PPE systems for surgeons with regard to protection from a virus spread via respiratory droplets. The testing was carried out using particle counters upstream and downstream on a mannequin wearing two different SS systems with and without modifications to the fan inlet.

The results show that using a layer of HEPA filter, cut to size and sealed to the fan inlet in the helmet, will reduce downstream particulates at the user's mouth by >99.5%; this is equivalent to a respirator mask. HEPA filter material is relatively cheap and can be used repeatedly, making this a viable alternative to disposable, and even resterilized, respirator masks in the setting of a respiratory-droplet-spread viral pandemic.

Quantifying the impact of the COVID-19 pandemic on orthopaedic trainees: a national perspective

Aims

We aim to objectively assess the impact of COVID-19 on mean total operative cases for all indicative procedures (as outlined by the Joint Committee on Surgical Training (JCST)) experienced by orthopaedic trainees in the deanery of the Republic of Ireland. Subjective experiences were reported for each trainee using questionnaires.

Methods

During the first four weeks of the nationwide lockdown due to COVID-19, the objective impact of the pandemic on each trainee's surgical caseload exposure was assessed using data from individual trainee logbook profiles in the deanery of the Republic of Ireland. Independent predictor variables included the trainee grade (ST 3 to 8), the individual trainee, the unit that the logbook was reported from, and the year in which the logbook was recorded. We used the analysis of variance (ANOVA) test to assess for any statistically significant predictor variables. The subjective experience of each trainee was captured using an electronic questionnaire.

Results

The mean number of total procedures per trainee over four weeks was 36.8 (7 to 99; standard deviation (SD) 19.67) in 2018, 40.6 (6 to 81; SD 17.90) in 2019, and 18.3 (3 to 65; SD 11.70) during the pandemic of 2020 (p = 0.043). Significant reductions were noted for all elective indicative procedures, including arthroplasty (p = 0.019), osteotomy (p = 0.045), nerve decompression (p = 0.024) and arthroscopy (p = 0.024). In contrast, none of the nine indicative procedures for trauma were reduced. There was a significant inter-unit difference in the mean number of total cases (p = 0.029) and indicative cases (p = 0.0005) per trainee. We noted that 7.69% (n = 3) of trainees contracted COVID-19.

Conclusion

During the COVID-19 pandemic, the mean number of operative cases per trainee has been significantly reduced for four of the 13 indicative procedures, as outlined by the JCST. Reassignment of trainees to high-volume institutions in the future may be a plausible approach to mitigate significant training deficits in those trainees worst impacted by the reduction in operative exposure.

Aspirin compared to enoxaparin or rivaroxaban for thromboprophylaxis following hip and knee replacement

Background The risk of venous thromboembolism following major orthopaedic surgery is among the highest for all surgical specialties. Our hospital guidelines for thromboprophylaxis following elective primary total hip or knee replacement are based on American College of Chest Physicians guidance. The most recent change to local guidelines was the introduction of the extended aspirin regimen as standard thromboprophylaxis. Objective To establish the appropriateness of this regimen by comparing venous thromboembolism rates in patients receiving extended aspirin to previous regimens. Setting The largest dedicated orthopaedic hospital in Ireland. Methods This was a retrospective cohort study. Data were collected from patient record software. All eligible patients undergoing primary total hip or knee replacement between 1st January 2010 and 30th June 2016 were included. Main outcome measure Venous thromboembolism up to 6 months post-operatively. Results Of the 6548 participants (55.3% female, mean age 65.4 years (± 11.8 years, 55.8% underwent total hip replacement), venous thromboembolism occurred in 65 (0.99%). Venous thromboembolism rate in both the inpatient enoxaparin group (n = 961) and extended aspirin group (n = 3460) was 1.04% and was 0.66% in the modified rivaroxaban group (n = 1212). Non-inferiority analysis showed the extended aspirin regimen to be equivalent to the modified rivaroxaban regimen. History of venous thromboembolism was the only significant demographic risk factor for post-operative venous thromboembolism (0.87% vs. 3.54%, p  = 0.0002). Conclusion In daily clinical practice, extended aspirin regimen is at least as effective as modified rivaroxaban for preventing clinically important venous thromboembolism among patients undergoing hip or knee arthroplasty who are discharged from the hospital without complications. Aspirin can be considered a safe and effective agent in the prevention of venous thromboembolism after total hip or total knee replacement.

Undergraduate Clinical Teaching in Orthopedic Surgery: A Randomized Control Trial Comparing the Effect of Case-Based Teaching and Bedside Teaching on Musculoskeletal OSCE Performance

INTRODUCTION

Musculoskeletal (MSK) complaints are the second most common reason for a hospital outpatient appointment in the US, and account for 19.5% of general practice consultations. Previous studies have shown that passive teaching in medical school does not imbue students with an adequate degree of confidence in MSK evaluation. The aim of this study was to conduct a randomized control trial to compare the effect of the gold standard small group tutorial of bedside teaching against case-based teaching (CBT) in relation to orthopedic surgery in medical students.

METHODS

All third-year medical students at our institution were invited to participate in a randomized control trial comparing CBT and bedside tutorials in relation to MSK. The primary outcome was student performance in an Objective Structured Clinical Examination (OSCE). Participants were randomized into 2 groups, receiving either a bedside tutorial or a case-based tutorial. Participants were then assigned self-directed learning before undergoing a final OSCE assessment. Student feedback was attained through a poststudy questionnaire.

RESULTS

Complete data was acquired for 96 study participants (n = 45 CBT; n = 51 bedside tutorial). The results of a linear regression model used to assess differences in the final OSCE scores, adjusting for the baseline OSCE score, gender, age, previous problem-based learning exposure and whether English was their first language or not showed no evidence of a difference between the bedside teaching group and the CBT group (mean difference: 0.34; 95% confidence interval: -3.79 to 4.47; p = 0.872). Almost all (95%) of the study participants felt that CBT was an important component in their learning.

CONCLUSION

There was no difference in OSCE performance between groups. The introduction of CBT before clinical placement in medical school could accentuate the clinical skills of students before transition into the apprenticeship model of clinical attachment.

A Qualitative and Quantitative Comparative Analysis of Commercial and Independent Online Information for Hip Surgery: A Bias in Online Information Targeting Patients?

BACKGROUND

Direct to consumer (DTC) advertising, targeting the public over the physician, is an increasingly pervasive presence in medical clinics. It is trending toward a format of online interaction rather than that of traditional print and television advertising.

METHODS

We analyze patient-focused Web pages from the top 5 companies supplying prostheses for total hip arthroplasties, comparing them to the top 10 independent medical websites. Quantitative comparison is performed using the Journal of American Medical Association benchmark and DISCERN criteria, and for comparative readability, we use the Flesch-Kincaid grade level, the Flesch reading ease, and the Gunning fog index. Content is analyzed for information on type of surgery and surgical approach.

RESULTS

There is a statistically significant difference between the independent and DTC websites in both the mean DISCERN score (independent 74.6, standard deviation [SD] = 4.77; DTC 32.2, SD = 10.28; P = .0022) and the mean Journal of American Medical Association score (Independent 3.45, SD = 0.49; DTC 1.9, SD = 0.74; P = .004). The difference between the readability scores is not statistically significantly. The commercial content is found to be heavily biased in favor of the direct anterior approach and minimally invasive surgical techniques.

CONCLUSION

We demonstrate that the quality of information on commercial websites is inferior to that of the independent sites. The advocacy of surgical approaches by industry to the patient group is a concern. This study underlines the importance of future regulation of commercial patient education Web pages.

A systematic review and meta-analysis of the diagnostic accuracy of MRI for suspected ACL and meniscal tears of the knee

PURPOSE

To determine the diagnostic accuracy of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of anterior cruciate ligament (ACL), medial meniscus and lateral meniscus tears in people with suspected ACL and/or meniscal tears.

METHODS

MEDLINE, Web of Science and the Cochrane library were searched from inception to March 2014. All prospective studies of the diagnostic accuracy of MRI or US against arthroscopy as the reference standard were included in the systematic review. Studies with a retrospective design and those with evidence of verification bias were excluded. Methodological quality of included studies was assessed using the QUADAS-2 tool. A meta-analysis of studies evaluating MRI to calculate the pooled sensitivity and specificity for each target condition was performed using a bivariate model with random effects. Sub-group and sensitivity analysis were used to examine the effect of methodological and other study variables.

RESULTS

There were 14 studies included in the meta-analysis of the accuracy of MRI for ACL tears, 19 studies included for medial meniscal tears and 19 studies for lateral meniscal tears. The summary estimates of sensitivity and specificity of MRI were 87 % (95 % CI 77-94 %) and 93 % (95 % CI 91-96 %), respectively, for ACL tears; 89 % (95 % CI 83-94 %) and 88 % (95 % CI 82-93 %), respectively, for medial meniscal tears; and 78 % (95 % CI 66-87 %) and 95 % (95 % CI 91-97 %), respectively, for lateral meniscal tears. Magnetic field strength had no significant effect on accuracy. Most studies had a high or unclear risk of bias. There were an insufficient number of studies that evaluated US to perform a meta-analysis.

CONCLUSION

This study provides a systematic review and meta-analysis of diagnostic accuracy studies of MRI and applies strict exclusion criteria in relation to the risk of verification bias. The risk of bias in most studies is high or unclear in relation to the reference standard. Concerns regarding the applicability of patient selection are also present in most studies.

LEVEL OF EVIDENCE

III.

The benefits and limitations of animal models for translational research in cartilage repair

Much research is currently ongoing into new therapies for cartilage defect repair with new biomaterials frequently appearing which purport to have significant regenerative capacity. These biomaterials may be classified as medical devices, and as such must undergo rigorous testing before they are implanted in humans. A large part of this testing involves in vitro trials and biomechanical testing. However, in order to bridge the gap between the lab and the clinic, in vivo preclinical trials are required, and usually demanded by regulatory approval bodies. This review examines the in vivo models in current use for cartilage defect repair testing and the relevance of each in the context of generated results and applicability to bringing the device to clinical practice. Some of the preclinical models currently used include murine, leporine, ovine, caprine, porcine, canine, and equine models. Each of these has advantages and disadvantages in terms of animal husbandry, cartilage thickness, joint biomechanics and ethical and licencing issues. This review will examine the strengths and weaknesses of the various animal models currently in use in preclinical studies of cartilage repair.

The Irish experience of Symphysiotomy: 40 years onwards

The art of symphysiotomy for delivery in the instance of cephalopelvic disproportion has been a dying art since the advent of caesarean section but in Ireland this surgical procedure was not abolished until 1992. This practice is still present in the developing world and in some circumstances used in developed countries. This study offers some insights on the 40-year follow-up of patients who had undergone symphysiotomy.

The prevalence of abnormal preoperative coagulation tests in pediatric patients undergoing spinal surgery for scoliosis

BACKGROUND CONTEXT

Multilevel spinal fusion surgery for deformity correcting spinal surgery in pediatric patients with scoliosis has typically been associated with significant blood loss. The mechanism of bleeding in such patients is not fully understood. Coagulation abnormalities, which may be associated with scoliosis, are thought to play a role.

PURPOSE

To document and compare the prevalence of preoperative coagulation abnormalities among patients with scoliosis attending a pediatric orthopedic department for spinal fusion surgery with patients attending for minor surgery.

STUDY DESIGN

An observational study. All patients were recruited from a pediatric tertiary referral center in Dublin, Ireland.

PATIENT SAMPLE

Coagulation profile results were prospectively collected over a 2-year period from 165 spinal surgery patients. In total, 175 patients were included in the non-scoliosis group. These patients attended the day ward for minor procedures and were recruited over a 4-month period.

OUTCOME MEASURES

The primary outcome measure was the coagulation profiles, which included prothrombin time, activated partial thromboplastin time (APTT), and thrombin time (TT). Levels of Coagulation Factors II, V, VII, and X were also recorded.

METHODS

All blood samples were sent to the haematology laboratory to establish the coagulation profile. The primary outcome was the presence of an abnormal coagulation screening test (if any of PT, APTT, or TT were abnormal). Prothrombin time, APTT, and TT were also analyzed as individual continuous variables, as well as Coagulation Factors II, V, VII, and X. Regression analysis was used to compare the coagulation profile of scoliosis patients with that of non-scoliosis patients. There were no outside funding sources or any potential conflict of interest associated with this study.

RESULTS

The scoliosis patients were more likely to have an abnormal preoperative screening test compared with non-scoliosis patients, with an odds ratio of 2.6. Further analysis showed statistically significant longer clotting times for patients with scoliosis compared with those without; PT (t=3.37, p=.001), APTT (t=4.26, p<.001), TT (t=4.52, p<.001). Of the coagulation factors analyzed, only factor X was significantly different in scoliosis patients compared with non-scoliosis controls (t=-4.41, p<.001).

CONCLUSIONS

Children with scoliosis have a higher prevalence of preoperative coagulation abnormalities compared with normal healthy patients.

Effect of prehabilitation on the outcome of anterior cruciate ligament reconstruction

BACKGROUND

Prehabilitation is defined as preparing an individual to withstand a stressful event through enhancement of functional capacity.

HYPOTHESIS

We hypothesized that a preoperative exercise program would enhance postoperative outcomes after anterior cruciate ligament reconstruction (ACLR).

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

Twenty volunteers awaiting ACLR were randomly assigned to a control or exercise intervention group. The exercise group completed a 6-week gym- and home-based exercise program. Assessments include single-legged hop test; quadriceps and hamstring peak torque and magnetic resonance imaging cross-sectional area (CSA); Modified Cincinnati Knee Rating System score; and muscle biopsy of the vastus lateralis muscle completed at baseline, preoperatively, and 12 weeks postoperatively. Myosin heavy chain (MHC) isoforms protein and messenger RNA (mRNA) expression were determined with SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) and RT-PCR (real-time polymerase chain reaction), respectively; IGF-1 (insulin-like growth factor 1), MuRF-1 (muscle RING-finger protein-1), and MAFbx (muscle atrophy f-box) mRNA expression were determined with quantitative RT-PCR.

RESULTS

Following 6 weeks of exercise intervention, the single-legged hop test results improved significantly in the exercise-injured limb compared with baseline (P = .001). Quadriceps peak torque in the injured limb improved with similar gains in CSA compared with baseline (P = .001). However, this was not significantly increased compared with the control group. Quadriceps and vastus medialis CSA were also larger in the exercise group than in controls (P = .0024 and P = .015, respectively). The modified Cincinnati score was better in the exercise-injured limb compared with baseline. At 12 weeks postoperatively, the rate of decline in the single-legged hop test was reduced in the exercise group compared with controls (P = .001). Similar trends were not seen for quadriceps peak torque and CSA. The vastus medialis CSA had regressed to similar levels as the control group (P = .008). The modified Cincinnati score continued to increase in the exercise group compared with controls (P = .004). The expression of the hypertrophic IGF-1 gene was significantly increased after the exercise intervention (P = .028), with a decrease back to baseline 12 weeks postoperatively (P = .012). Atrophic MuRF-1 gene expression was decreased after intervention compared with baseline (P = .05) but increased again at 12 weeks postoperatively (P = .03). The MAFbx levels did not change significantly in either group and within each time point. On the mRNA level, there was a shift from MHC-IIx isoform to MHC-IIa after exercise, with significant changes compared with control preoperatively (P = .028). Protein testing was able to reproduce this increase for MHC-IIa isoform expression only.

CONCLUSION

The 6-week progressive prehabilitation program for subjects undergoing ACLR led to improved knee function based on the single-legged hop test and self-reported assessment using the modified Cincinnati score. These effects were sustained at 12 weeks postoperatively. This study supports prehabilitation as a consideration for patients awaiting ACLR; however, further studies are warranted.

Cemented versus uncemented fixation in total hip replacement: a systematic review and meta-analysis of randomized controlled trials

The optimal method of fixation for primary total hip replacements (THR), particularly fixation with or without the use of cement is still controversial. In a systematic review and metaanalysis of all randomized controlled trials comparing cemented versus uncemented THRS available in the published literature, we found that there is no significant difference between cemented and uncemented THRs in terms of implant survival as measured by the revision rate. Better short-term clinical outcome, particularly an improved pain score can be obtained with cemented fixation. However, the results are unclear for the long-term clinical and functional outcome between the two groups. No difference was evident in the mortality and the post operative complication rate. On the other hand, the radiographic findings were variable and do not seem to correlate with clinical findings as differences in the surgical technique and prosthesis design might be associated with the incidence of osteolysis. We concluded in our review that cemented THR is similar if not superior to uncemented THR, and provides better short term clinical outcomes. Further research, improved methodology and longer follow up are necessary to better define specific subgroups of patients in whom the relative benefits of cemented and uncemented implant fixation can be clearly demonstrated.

Computational modelling of long bone fractures fixed with locking plates - How can the risk of implant failure be reduced?

BACKGROUND AND PURPOSE

The Locking Compression Plate (LCP) is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability and the risk of implant failure can best be controlled.

METHODS

Upon validation, a finite element model of an LCP attached to a cylinder was developed to simulate and analyse the biomechanics of a transverse long bone fracture fixed with a locking plate. Of special interest were the factors influencing the mechanical conditions at the fracture site, the control of interfragmentary movement and implant failure.

RESULTS

Several factors were shown to influence stability in compression. Increasing translation and/or fracture angle post fixation reduced construct stability. Axial stiffness was also influenced by the working length and plate-bone distance. The fracture gap had no effect on the construct stability when no bone contact occurred during loading. Stress analysis of the LCP demonstrated that the maximum Von Mises stresses were found in the innermost screws at the screw-head junction.

INTERPRETATION

For the clinical use of the LCP as a locked internal fixator in fractures with an interfragmentary gap of 1 mm, at least two to four plate holes near the fracture gap should be omitted to allow fracture motion and bone contact to occur. This will also achieve a larger area of stress distribution on the plate and reduce the likelihood of fatigue failure due to cyclic loading.

The accuracy and inter-observer reliability of acetate templating in total hip arthroplasty

AIM

The accuracy and inter-observer reliability (IOR) of acetate templating on hard copy X-rays in 33 primary total hip arthroplasties as measured by consultant and trainee surgeons was analyzed to find out how accurate are junior surgeons undertaking specialty training.

METHODS

The study was questionnaire-based using a prospective cohort over a 4 weeks period. The Surgeon measurements of acetabular cup, femoral stem and femoral offset sizes were noted following acetate measurements and then compared with the final implant chosen during surgery.

RESULTS

Prediction of sizing to within one size of the final match size was 75% accurate for cup and 91% accurate for femoral stem. Prediction of exact femoral offset sizes was 91% accurate. Templating showed strong IOR between senior consultant surgeon and junior trainee registrar within one size for cup (83%) and stem (100%) and for exact hip offset prediction (92%).

CONCLUSION

We conclude that acetate templating on hard copy X-rays is beneficial to surgeons to gauge acetabular cup and femoral stem size to within one size range. This further helps in predicting nearly exact femoral offset size.

Effects of home-based resistance training and neuromuscular electrical stimulation in knee osteoarthritis: a randomized controlled trial

BACKGROUND

Quadriceps femoris muscle (QFM) weakness is a feature of knee osteoarthritis (OA) and exercise programs that strengthen this muscle group can improve function, disability and pain. Traditional supervised resistance exercise is however resource intensive and dependent on good adherence which can be challenging to achieve in patients with significant knee OA. Because of the limitations of traditional exercise programs, interest has been shown in the use of neuromuscular electrical stimulation (NMES) to strengthen the QFM. We conducted a single-blind, prospective randomized controlled study to compare the effects of home-based resistance training (RT) and NMES on patients with moderate to severe knee OA.

METHODS

41 patients aged 55 to 75 years were randomised to 6 week programs of RT, NMES or a control group receiving standard care. The primary outcome was functional capacity measured using a walk test, stair climb test and chair rise test. Additional outcomes were self-reported disability, quadriceps strength and cross-sectional area. Outcomes were assessed pre- and post-intervention and at 6 weeks post-intervention (weeks 1, 8 and 14 respectively).

RESULTS

There were similar, significant improvements in functional capacity for the RT and NMES groups at week 8 compared to week 1 (p ≤ 0.001) and compared to the control group (p < 0.005), and the improvements were maintained at week 14 (p ≤ 0.001). Cross sectional area of the QFM increased in both training groups (NMES: +5.4%; RT: +4.3%; p = 0.404). Adherence was 91% and 83% in the NMES and RT groups respectively (p = 0.324).

CONCLUSIONS

Home-based NMES is an acceptable alternative to exercise therapy in the management of knee OA, producing similar improvements in functional capacity.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN85231954.

High power, low frequency ultrasound: meniscal tissue interaction and ablation characteristics

This study evaluates high power low frequency ultrasound transmitted via a flat vibrating probe tip as an alternative technology for meniscal debridement in the bovine knee. An experimental force controlled testing rig was constructed using a 20 kHz ultrasonic probe suspended vertically from a load cell. Effect of variation in amplitude of distal tip displacement (242-494 μm peak-peak) settings and force (2.5-4.5 N) on tissue removal rate (TRR) and penetration rate (PR) for 52 bovine meniscus samples was analyzed. Temperature elevation in residual meniscus was measured by embedded thermocouples and histologic analysis. As amplitude or force increases, there is a linear increase in TRR (Mean: 0.9 to 11.2 mg/s) and PR (Mean: 0.08 to 0.73 mm/s). Maximum mean temperatures of 84.6°C and 52.3°C were recorded in residual tissue at 2 mm and 4 mm from the ultrasound probe-tissue interface. There is an inverse relationship between both amplitude and force, and temperature elevation, with higher settings resulting in less thermal damage.

The role of Dkk1 in bone mass regulation: correlating serum Dkk1 expression with bone mineral density

The Wnt/β-catenin pathway is a major signaling cascade in bone biology, playing a key role in regulating bone development and remodeling, with aberrations in signaling resulting in disturbances in bone mass. The objectives of our study were to correlate serum Dkk1 expression with bone mineral density (BMD) and assess the potential role of Dkk1 as a serological marker of bone mass. Serum was collected from a cohort of patients (n = 36), 18 patients with a reduced BMD and 18 control patients. Serum Dkk1 expression as quantified by ELISA was correlated with lumbar and femoral t- and z-scores. Serum Dkk1 concentration in the osteoporosis group was significantly higher than control group (941 ± 116 vs. 558 ± 47 pg/ml, p < 0.01). Serum Dkk1 expression was highly correlated with bone mass variables with inverse associations found between serum Dkk1 expression and lumbar t-score (r = -0.34, p = 0.00433), lumbar z-score (r = -0.22, p = 0.1907), femur t-score (r = -0.42, p = 0.0101), and femur z-score (r = -0.43, p = 0.0089). Our data further emphasizes the pivotal role played by Wnt/β-catenin signaling in bone mass regulation. Dkk1, a powerful antagonist of canonical Wnt signaling, may have a role to play as a serological marker for disorders of bone mass, warranting further evaluation.

Assessment of a new undergraduate module in musculoskeletal medicine

BACKGROUND

Despite the high prevalence of musculoskeletal disorders seen by primary care physicians, numerous studies have demonstrated deficiencies in the adequacy of musculoskeletal education at multiple stages of medical education. The aim of this study was to assess a newly developed module in musculoskeletal medicine for use at European undergraduate level (i.e., the medical-school level).

METHODS

A two-week module in musculoskeletal medicine was designed to cover common musculoskeletal disorders that are typically seen in primary care. The module incorporated an integrated approach, including core lectures, bedside clinical examination, and demonstration of basic practical procedures. A previously validated examination in musculoskeletal medicine was used to assess the cognitive knowledge of ninety-two students on completion of the module. A historical control group (seventy-two students) from a prior course was used for comparison.

RESULTS

The new module group (2009) performed significantly better than the historical (2006) control group in terms of score (62.3% versus 54.3%, respectively; p < 0.001) and pass rate (38.4% versus 12.5%, respectively; p = 0.0002). In a subgroup analysis of the new module group, students who enrolled in the graduate entry program (an accelerated four-year curriculum consisting of students who have already completed an undergraduate university degree) were more likely to perform better in terms of average score (72.2% versus 57%, respectively; p < 0.001) and pass rates (70.9% versus 21.4%, respectively; p < 0.001) compared with students who had enrolled via the traditional undergraduate route. In terms of satisfaction rates, the new module group reported a significantly higher satisfaction rate than that reported by the historical control group (63% versus 15%, respectively; p < 0.001).

CONCLUSIONS

In conclusion, the musculoskeletal module described in this paper represents an educational advance at undergraduate (i.e., medical-school) level as demonstrated by the improvement in scores in a validated examination. As pressure on medical curricula grows to accommodate advancing medical knowledge, it is important to continue to improve, assess, and consolidate the position of musculoskeletal medicine in contemporary medical education.

Outcome of periacetabular osteotomy for the management of acetabular dysplasia: experience in an academic centre

Periacetabular osteotomy (PAO) is a very effective reconstructive procedure for treatment of acetabular dysplasia. An orthopaedic paediatric surgeon and a reconstructive hip arthroplasty surgeon performed this procedure together in the early phase of their learning curve and then performed it individually. The early clinical and radiographic results of 85 consecutive PAOs performed in this academic orthopaedic unit were reviewed. The mean Merle-d'Aubigné score increased from 12.4 preoperatively to 16 at follow-up. Pre-operatively 73 hips were anteverted and 12 were neutral or retroverted. The mean angle of Wiberg improved from 5 degrees to 21 degrees (p < 0.0001) in anteverted hips, and from 9 degrees to 30 degrees in neutral or retroverted hips. The mean angle of Lequesne and de Sèze improved from 6 degrees to 35 degrees (p < 0.0001) in anteverted hips, and in neutral or retroverted hips from 9 degrees to 30 degrees (p < 0.0001). The acetabular index improved from 26 degrees to 8 degrees (p < 0.0001) in anteverted hips, and from 21 degrees to 7 degrees (p < 0.0001) in neutral or retroverted hips. Over the 7 year period the blood loss and operative time improved from 2000 ml to 900 ml and 4 hours to 2 hours respectively. Four hips (four patients) required conversion to total hip replacement. The radiographic correction and improved clinical scores are similar to those in previous studies. This study shows a survival rate of 94% at 58 months following periacetabular osteotomy. The learning curve and the early results of this procedure performed in our academic unit are encouraging.

Cobalt ions induce chemokine secretion in a variety of systemic cell lines

BACKGROUND AND PURPOSE

Metal ion toxicity both locally and systemically following MoM hip replacements remains a concern. Cobalt ions have been shown to induce secretion of proinflammatory chemokines locally; however, little is known about their effect systemically. We investigated the in vitro effect of cobalt ions on a variety of cell lines by measuring production of the proinflammatory chemokines IL-8 and MCP-1.

METHOD

Renal, gastrointestinal, and respiratory epithelium and also neutrophils and monocytes were exposed to cobalt ions at 4, 12, 24, and 48 hours.

RESULTS

We found that cobalt ions enhanced the secretion of IL-8 and MCP-1 in renal epithelial cells, gastric and colon epithelium, monocytes and neutrophils, and small airway epithelial cells but not in alveolar cells. Secretion of IL-8 and MCP-1 was markedly elevated in renal epithelium, where a 16-fold and 7-fold increase occurred compared to controls. There was a 6-fold and 4-fold increase in IL-8 and MCP-1 secretion in colon epithelium and a 4-fold and 3-fold increase in gastric epithelium. Small airway epithelial cells showed a maximum increase in secretion of 8-fold (IL-8) and of 4-fold (MCP-1). The increase in chemokine secretion observed in alveolar cells was moderate and did not reach statistical significance. Monocytes and neutrophils showed a 2.5-fold and 2-fold increase in IL-8 secretion and a 6-fold and 4-fold increase in MCP-1 secretion at 48 and 24 hours, respectively.

INTERPRETATION

These data demonstrate the potent bioactivity of cobalt ions in a variety of cell types and the potential to induce a proinflammatory response.

Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation

BACKGROUND

The Wnt/β-catenin pathway is a major signaling cascade in bone biology, playing a key role in bone development and remodeling. The objectives of this study were firstly, to determine the effects of dexamethasone exposure on Wnt/β-catenin signaling at an intracellular and transcriptional level, and secondly, to assess the phenotypic effects of silencing the Wnt antagonist, Dickkopf-1 (Dkk1) in the setting of dexamethasone exposure.

METHODS

Primary human osteoblasts were exposed in vitro to 10-8 M dexamethasone over a 72 h time course. The phenotypic marker of osteoblast differentiation was analyzed was alkaline phosphatase activity. Intracellular β-catenin trafficking was assessed using immunoflourescence staining and TCF/LEF mediated transcription was analyzed using a Wnt luciferase reporter assay. Dkk1 expression was silenced using small interfering RNA (siRNA).

RESULTS

Primary human osteoblasts exposed to dexamethasone displayed a significant reductions in alkaline phosphatase activity over a 72 h time course. Immunoflourescence analaysis of β-catenin localization demonstrated a significant reduction in intracytosolic and intranuclear β-catenin in response to dexamethasone exposure. These changes were associated with a reduction of TCF/LEF mediated transcription. Silencing Dkk1 expression in primary human osteoblasts exposed to dexamethasone resulted in an increase in alkaline phosphatase activity when compared to scrambled control.

CONCLUSIONS

Wnt/β-catenin signaling plays a key role in regulating glucocorticoid-induced osteoporosis in vitro. Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation. Targeting of the Wnt/β-catenin signaling pathway offers an exciting opportunity to develop novel anabolic bone agents to treat osteoporosis and disorders of bone mass.

Risk analysis of blood transfusion requirements in emergency and elective spinal surgery

Spinal surgery has long been considered to have an elevated risk of perioperative blood loss with significant associated blood transfusion requirements. However, a great variability exists in the blood loss and transfusion requirements of differing patients and differing procedures in the area of spinal surgery. We performed a retrospective study of all patients undergoing spinal surgery who required a transfusion≥1 U of red blood cells (RBC) at the National Spinal Injuries Unit (NSIU) at the Mater Misericordiae University Hospital over a 10-year period. The purpose of this study was to identify risk factors associated with significant perioperative transfusion allowing the early recognition of patients at greatest risk, and to improve existing transfusion practices allowing safer, more appropriate blood product allocation. 1,596 surgical procedures were performed at the NSIU over a 10-year period. 25.9% (414/1,596) of these cases required a blood transfusion (n=414). Surgical groups with a significant risk of requiring a transfusion>2 U RBC included deformity surgery (RR=3.351, 95% CI 1.123-10.006, p=0.03), tumor surgery (RR=3.298, 95% CI 1.078-10.089, p=0.036), and trauma surgery (RR=2.444, 95% CI 1.183-5.050, p=0.036). Multivariable logistic regression analysis identified multilevel surgery (>3 levels) as a significant risk of requiring a transfusion>2 U RBC (RR=4.682, 95% CI 2.654-8.261, p<0.0001). Several risk factors in the spinal surgery patient were identified as corresponding to significant transfusion requirements. A greater awareness of the risk factors associated with transfusion is required in order to optimize patient management.

Effects of preoperative neuromuscular electrical stimulation on quadriceps strength and functional recovery in total knee arthroplasty. A pilot study

Background

Supervised preoperative muscle strengthening programmes (prehabilitation) can improve recovery after total joint arthroplasty but are considered resource intensive. Neuromuscular electrical stimulation (NMES) has been shown to improve quadriceps femoris muscle (QFM) strength and clinical function in subjects with knee osteoarthritis (OA) however it has not been previously investigated as a prehabilitation modality.

Methods

This pilot study assessed the compliance of a home-based, NMES prehabilitation programme in patients undergoing total knee arthroplasty (TKA). We evaluated its effect on preoperative and postoperative isometric quadriceps femoris muscle (QFM) strength, QFM cross-sectional area (CSA) and clinical function (subjective and objective). Seventeen subjects were recruited with 14 completing the study (NMES group n = 9; Control group n = 5).

Results

Overall compliance with the programme was excellent (99%). Preoperative QFM strength increased by 28% (p > 0.05) with associated gains in walk, stair-climb and chair-rise times (p < 0.05). Early postoperative strength loss (approximately 50%) was similar in both groups. Only the NMES group demonstrated significant strength (53.3%, p = 0.011) and functional recovery (p < 0.05) from 6 to 12 weeks post-TKA. QFM CSA decreased by 4% in the NMES group compared to a reduction of 12% in the control group (P > 0.05) at 12 weeks postoperatively compared to baseline. There were only limited associations found between objective and subjective functional outcome instruments.

Conclusions

This pilot study has shown that preoperative NMES may improve recovery of quadriceps muscle strength and expedite a return to normal activities in patients undergoing TKA for OA. Recommendations for appropriate outcome instruments in future studies of prehabilitation in TKA have been provided.

The long-term functional outcome of type II odontoid fractures managed non-operatively

Odontoid fractures currently account for 9-15% of all adult cervical spine fractures, with type II fractures accounting for the majority of these injuries. Despite recent advances in internal fixation techniques, the management of type II fractures still remains controversial with advocates still supporting non-rigid immobilization as the definitive treatment of these injuries. At the NSIU, over an 11-year period between 1 July 1996 and 30 June 2006, 66 patients (n = 66) were treated by external immobilization for type II odontoid fractures. The medical records, radiographs and CT scans of all patients identified were reviewed. Clinical follow-up evaluation was performed using the Cervical Spine Outcomes Questionnaire (CSOQ). The objectives of this study were to evaluate the long-term functional outcome of patients suffering isolated type II odontoid fractures managed non-operatively and to correlate patient age and device type with clinical and functional outcome. Of the 66 patients, there were 42 males and 24 females (M:F = 1.75:1) managed non-operatively for type II odontoid fractures. The mean follow-up time was 66 months. Advancing age was highly correlated with poorer long-term functional outcomes when assessing neck pain (r = 0.19, P = 0.1219), shoulder and arm pain (r = 0.41, P = 0.0007), physical symptoms (r = 0.25, P = 0.472), functional disability (r = 0.24, P = 0.0476) and psychological distress (r = 0.41, P = 0.0007). Patients >65 years displayed a higher rate of pseudoarthrosis (21.43 vs. 1.92%) and established non-union (7.14 vs. 0%) than patients <65 years. The non-operative management of type II odontoid fractures is an effective and satisfactory method of treating type II odontoid fractures, particularly those of a stable nature. However, patients of advancing age have been demonstrated to have significantly poorer functional outcomes in the long term. This may be linked to higher rates of non-union.

Overuse ankle injuries in professional Irish dancers

BACKGROUND

Overuse ankle injuries have been described in elite athletes and professional ballet dancers however the spectrum of injuries experienced by professional Irish dancers has not been defined.

METHODS

A troupe of actively performing dancers from an Irish-dance show were recruited (eight male, ten female; mean age, 26 years). The prevalence of overuse injuries in the right ankle was determined from magnetic resonance imaging. Foot and ankle self-report questionnaires were also completed (AOFAS and FAOS).

RESULTS

Only three ankles were considered radiologically normal. Achilles tendinopathy, usually insertional, was the most frequent observation (n=14) followed by plantar fasciitis (n=7), bone oedema (n=2) and calcaneocuboid joint degeneration (n=2). There were limited correlations between MRI patterns and clinical scores indicating that many conditions are sub-clinical. Dancers with ankle pain had poor low (p=0.004) and high (p=0.013) level function.

CONCLUSIONS

Overuse ankle injuries are common in Irish dancers. Incorporating eccentric exercises and plantar fascia stretching into a regular training program may benefit this population.

Cobalt ions induce chemokine secretion in primary human osteoblasts

Chemokines are major regulators of the inflammatory response and have been shown to play an important role in periprosthetic osteolysis. Titanium particles have previously been shown to induce IL-8 and MCP-1 secretion in osteoblasts. These chemokines result in the chemotaxis and activation of neutrophils and macrophages, respectively. Despite a resurgence in the use of cobalt-chromium-molybdenum alloys in metal-on-metal arthroplasty, cobalt and chromium ion toxicity in the periprosthetic area has been insufficiently studied. In this study we investigate the in vitro effect of cobalt ions on primary human osteoblast activity. We demonstrate that cobalt ions rapidly induce the protein secretion of IL-8 and MCP-1 in primary human osteoblasts. This elevated chemokine secretion is preceded by an increase in the transcription of the corresponding chemokine gene. Using a Transwell migration chemotaxis assay we also demonstrate that the chemokines secreted are capable of inducing neutrophil and macrophage migration. Furthermore, cobalt ions significantly inhibit osteoblast function as demonstrated by reduced alkaline phosphatase activity and calcium deposition. In aggregate these data demonstrate that cobalt ions can activate transcription of the chemokine genes IL-8 and MCP-1 in primary human osteoblasts. Cobalt ions are not benign and may play an important role in the pathogenesis of osteolysis by suppressing osteoblast function and stimulating the production and secretion of chemokines that attract inflammatory and osteoclastic cells to the periprosthetic area.

Tourniquets and exsanguinators: a potential source of infection in the orthopedic operating theater?

BACKGROUND AND PURPOSE

Fomites are increasingly being recognised as a source of hospital-acquired infection. We have therefore assessed tourniquets and exsanguinators for the presence of bacterial pathogens in 1 elective and 2 trauma orthopedic hospitals.

MATERIAL AND METHODS

Swabs were taken prior to and after decontaminating these devices with 1 of 3 different cleaning modalities. These were then assessed for colony counts and organisms identified.

RESULTS

Bacteria commonly implicated in surgical site infections such as coagulase-negative staphylococci, Staphylococcus aureus and Proteus spp. were prevalent. We also found a resistant strain of Acinetobacter and Candida. Exsanguinators were the most heavily contaminated devices, and colony counts in the trauma hospitals were up to 400% higher than in the elective hospital. Alcohol- and non-alcohol-based sterile wipes were both highly effective in decontaminating the devices.

INTERPRETATION

Infectious organisms reside on the tourniquets and exsanguinators presently used in the orthopedic theater. These fomites may possibly be a source of surgical site infection. We have demonstrated a simple and effective means of decontaminating these devices between cases.

The posterior cruciate ligament-preserving total knee replacement: do we 'preserve' it? A radiological study

Our aims were to map the tibial footprint of the posterior cruciate ligament (PCL) using MRI in patients undergoing PCL-preserving total knee replacement, and to document the disruption of this footprint as a result of the tibial cut. In 26 consecutive patients plain radiography and MRI of the knee were performed pre-operatively, and plain radiography post-operatively. The lower margin of the PCL footprint was located a mean of 1 mm (-10 to 8) above the upper aspect of the fibular head. The mean surface area was 83 mm(2) (49 to 142). One-third of patients (8 of 22) had tibial cuts made below the lowest aspect of the PCL footprint (complete removal) and one-third (9 of 22) had cuts extending into the footprint (partial removal). The remaining patients (5 of 22) had footprints unaffected by the cuts, keeping them intact. Our study highlights the wide variation in the location of the tibial PCL footprint when referenced against the fibula. Proximal tibial cuts using conventional jigs resulted in the removal of a significant portion, if not all of the PCL footprint in most of the patients in our study. Our findings suggest that when performing PCL-retaining total knee replacement the tibial attachment of the PCL is often removed.

The management and functional outcome of isolated burst fractures of the fifth lumbar vertebra

STUDY DESIGN

We retrospectively reviewed 14 cases of isolated burst fractures of the fifth lumbar vertebra (L5) presenting over a 10-year period to the National Spinal Injuries Unit (NSIU) of the Republic of Ireland.

OBJECTIVES

The objective was to evaluate treatment outcomes in patients suffering isolated burst fractures of L5 without neurologic compromise managed operatively and nonoperatively.

SUMMARY OF BACKGROUND DATA

Burst fractures of L5 represent a very small proportion of all spinal injuries. The unique anatomic and biomechanical characteristics of this region protect it from traumatic injury.

METHODS

Fourteen patients (n = 14) were managed for isolated burst fractures of L5 at the NSIU over a 10-year period. The Hospital Inpatient Enquiry System and the NSIU Database identified our study cohort. A retrospective analysis of the medical records, radiographs, and CT scans of all patients identified was performed. Loss of anterior vertebral height, degree of kyphotic deformity, and percentage retropulsion were recorded at several phases of treatment. Follow-up clinical evaluation was performed with respect to pain status, work and recreational restrictions, along with overall patient satisfaction.

RESULTS

Of the study cohort (n = 14), 10 patients were managed nonoperatively and 4 patients operatively. The nonoperative group showed a superior radiographic outcome at follow-up, with the nonoperative group showing a mean loss of anterior vertebral height of 15.7% and a mean kyphotic deformity of 10.4 degrees. The operative group, in contrast, had a mean loss of anterior vertebral height of 19% and mean kyphotic deformity of 11 degrees at follow-up. The nonoperative group additionally exhibited superior results at clinical follow-up regarding pain status, work and recreational restrictions, and overall satisfaction.

CONCLUSIONS

In the largest series to date of isolated burst fractures of L5, we strongly advocate the nonoperative management of these injuries, particularly in cases of moderate bony deformity, minimal canal compromise, and no neurologic deficit.

I can C clearly now the rail has gone!

Accurate intra-operative imaging is vital in orthopaedic pelvic surgery in order to achieve precise reduction of fractures and correct positioning of osteotomies. Radiological assessment is carried out, in most centres, using standard C-arm fluoroscopy. A limitation of this technique is that it is not always possible to obtain accurate images in all planes due to the presence of radiopaque materials on the operating table. One such example is the 45 degrees oblique view, which is frequently obscured by the presence of a metal rail on the operating table. We report on a practical solution; the development of a unique 360 degrees radiolucent table by placing a sheet of Perspex material between two standard operating tables, which allows for perfect radiological exposure of the pelvis in all planes.

Nontuberculous pyogenic spinal infection in adults: a 12-year experience from a tertiary referral center

STUDY DESIGN

We performed a retrospective review of 48 cases of pyogenic spinal infection presenting over a 12-year period to the National Spinal Injuries Unit (NSIU) of the Republic of Ireland. The NSIU is the tertiary referral center for all adult spinal injuries and diseases of the spine warranting surgical intervention in the Republic of Ireland.

OBJECTIVES

The objective of this study was to analyze the presentation, etiology, management, and outcome of nontuberculous pyogenic spinal infection in adults.

SUMMARY OF BACKGROUND DATA

Pyogenic spinal infection encompasses a broad range of clinical entities, including spondylodiscitis, septic discitis, vertebral osteomyelitis, and epidural abscess. Management of pyogenic spinal infection can involve conservative methods and surgical intervention.

METHODS

The medical records, radiologic imaging, and bacteriology results of 48 patients with pyogenic vertebral osteomyelitis from 1992 through 2004 were reviewed. The Hospital Inpatient Enquiry (HIPE) System and the NSIU Database were used to identify our study cohort.

RESULTS

The average age of presentation was 59 years with an even distribution between males and females. Most patients (21 of 48) were symptomatic for between 2 and 6 weeks before presenting to hospital. The most frequently isolated pathogen was Staphylococcus aureus, in 23 of 48 cases (48%); 35 of 48 cases (73%) were managed by conservative measures alone, including antibiotic therapy and spinal bracing. However, in 13 of 48 cases (27%), surgical intervention was required because of neurologic compromise or mechanical instability.

CONCLUSIONS

In the majority of cases, conservative management of pyogenic spinal infection with antibiotic therapy and spinal bracing is very successful. However, in a minority of cases, surgical intervention is warranted and referral to a specialist center is appropriate.

Spinal injuries in Irish rugby: a ten-year review

This study assessed the frequency of acute injury to the spinal cord in Irish Rugby over a period of ten years, between 1995 and 2004. There were 12 such injuries; 11 were cervical and one was thoracic. Ten occurred in adults and two in schoolboys. All were males playing Rugby Union and the mean age at injury was 21.6 years (16 to 36). The most common mechanism of injury was hyperflexion of the cervical spine and the players injured most frequently were playing at full back, hooker or on the wing. Most injuries were sustained during the tackle phase of play. Six players felt their injury was preventable. Eight are permanently disabled as a result of their injury.

Transforming growth factor-beta (TGF-β) in acute injuries of the spinal cord

Injuries to the spinal cord may be associated with increased healing of fractures. This can be of benefit, but excessive bone growth can also cause considerable adverse effects.

We evaluated two groups of patients with fractures of the spinal column, those with neurological compromise (n = 10) and those without (n = 15), and also a control group with an isolated fracture of a long bone (n = 12). The level of transforming growth factor-beta (TGF-β), was measured at five time points after injury (days 1, 5, 10, 42 and 84).

The peak level of 142.79 ng/ml was found at day 84 in the neurology group (p < 0.001 vs other time points). The other groups peaked at day 42 and had a decrease at day 84 after injury (p ≤ 0.001).

Our findings suggest that TGF-β may have a role in the increased bone turnover and attendant complications seen in patients with acute injuries to the spinal cord.

Trends in RTA related spinal injuries: the post penalty points era

BACKGROUND

On October 31st 2002 a system of cumulative penalty points for road traffic offences was introduced. Early evidence suggested a reduction in road traffic accident (RTA) related morbidity.

AIMS

To evaluate the persistence of the initial reduction in RTA related spinal injuries following penalty points introduction.

METHODS

Retrospective review of all acute spinal trauma admissions to the NSIU between November 1st 1998 and October 31st 2004 (n = 966). Patient demographics and injury aetiology were assessed. Follow-up questionnaires evaluated RTA circumstances.

RESULTS

RTA related spinal injuries accounted for 39.3% of NSIU admissions. These injuries were significantly more common in males aged 16-24, drivers (70.8%), on routine journeys (77.5%) and rural roads (48.8%). The highest proportion of accidents occurred during weekends (64.3% from Fri-Sun) and from midnight to 6am (29.3%).

CONCLUSIONS

The initial reduction in RTA related spinal injuries has not been sustained. Young male drivers are the greatest at risk group.

Vertebral fractures and concomitant fractures of the sternum

From October 1996 to August 2001, 721 patients with vertebral fractures were admitted to our unit. Ten patients suffered from vertebral fractures and concomitant sternal fractures. The clinical notes and plain film radiographs of these patients were studied. The average age of the patients was 37 (20-69) years. Nine had been involved in road traffic accidents. Three patients had fractures of the cervical spine, six of the upper thoracic spine (T1-T6) and one had a lumbar spine fracture. The extra-thoracic fracture group included two patients with neurological compromise and two patients who were neurologically intact. The entire upper thoracic fracture group suffered neurological compromise, with four patients suffering complete neurological deficit. In addition, four of these patients suffered potentially life-threatening intra-thoracic injuries. The relative severity of the neurological compromise and the attendant injuries in the upper thoracic fracture group offers compelling evidence in support of the "fourth column" theory, as expressed by Berg [Berg EE (1993), The sternal-rib complex. A possible fourth column in thoracic spine fractures. Spine 18(13):1916-1919].

The need for multidisciplinary management of patients with upper thoracic spine fractures caused by high-velocity impact: a review of 32 surgically stabilised cases

PURPOSE

To analyse the characteristics of patients who underwent surgery for fractures of the upper thoracic spine (T1-T6) in our institution. The thoracic spine is supported by the rib cage and associated ligaments; therefore, displacement and fracture of the upper thoracic spine in healthy young adults require a great force. The relatively narrow spinal canal around the spinal cord in this area could result in severe neurological deficit should fractures occur.

METHODS

The treatment course of 32 patients (26 men and 6 women) who underwent surgery for fractures of the upper thoracic spine between February 1995 and March 2001 was retrospectively reviewed. Parameters of injuries and treatment methods were evaluated.

RESULTS

Of the 32 patients, 29 were injured in traffic accidents (15 motorcycle and 14 vehicle), 2 in falls, and one by a heavy door falling on his back. 29 patients had spinal fractures at more than one level. 23 patients had complete, 7 had incomplete, and 2 had no neurological deficit. 30 patients required multiple modalities of radiological imaging (in addition to plain radiography) for diagnosis. 20 patients sustained other injuries apart from spinal fractures, 15 of them had associated chest injuries.

CONCLUSION

High-velocity fractures of the upper thoracic spine are injuries with devastating consequences, and can result in severe neurological deficit and concomitant injuries. These patients are best treated by a multidisciplinary approach.

Speed and spinal injuries

Road traffic accidents (RTA) are a significant cause of spinal trauma. On the 31st of October 2002 a new penalty system for speed related driving offences was introduced in Ireland. Our intention was to assess the effects of the introduction of this system on the activity of the National Spinal Injuries Centre (NSIC) with a retrospective review of all admissions from November 1998 until October 2003. The number of new acute admissions to the spinal injury unit during the study period was 831. In the first 6 months of the new system the number of RTA related admissions fell significantly to 17 compared to an average of 33 in the preceding 4 years. However, this effect was not maintained in the second 6 months. The fall in spinal injuries following RTA in the first 6 months of the new system parallels the pattern of road death reduction in this period. This suggests that driving behaviour can be modified with direct benefits in reducing spinal injuries. However, this effect has not persisted in the second 6 months of the new system suggesting that to maintain this change the perception and familiarity of a penalty are important factors in its impact.

Anthropometrical analysis of cervical spine injuries

To date the principal focus of the mechanism of cervical spine fracture has been directed towards head/neck circumference and vertebral geometric dimensions. However the role of other measurements, including chest circumference and neck length, in a standard cervical fracture population has not yet been studied in detail. Cervical fractures often involve flexion/extension type mechanisms of injury, with the head and cervical spine flexing/extending, using the thorax as an end point of contact. Thus, the thorax may play an important role in neck injuries.

STUDY DESIGN

We prospectively studied all patients with cervical spine fractures who were admitted to the National Spinal Injuries Unit from 1 July 2000 to 1 March 2001. Anthropometrical measurement of head circumference, neck circumference, chest circumference, and neck length were analysed. Ages ranged from 18 to 55 years, and all patients with concomitant cervical pathology were excluded from the study. Mechanism of injury involved flexion/extension type injuries in all cases; those with direct axial loading were excluded. A control group of 40 patients (age 18-50 years) involved in high velocity trauma with associated long bone fractures, in whom cervical injury was suspected, but who were without any cervical fracture, or associated pathology, were similarly measured.

RESULTS

Our analysis revealed a statistically significant increase in chest size in the male control group versus the male fracture group (97.89 cm versus 94.19 cm, P < 0.05, Student's t-test). There was a correspondingly significant increase in chest circumference between the female controls versus the female fracture group (92.33 cm versus 88.88 cm, P < 0.05, Student's t-test). Our results revealed no statistical difference in head circumference, neck circumference, or neck length between each of the groupings. These results indicate a proportionately larger chest may be a protective factor in cervical spine fractures.

Quantitative analysis and classification of gait patterns in cerebral palsy using a three-dimensional motion analyzer

Gait disorders in cerebral palsy can be accurately analyzed using the CODA-3 system presenting quantitative data representing movement of the hip, knee, and ankle in the sagittal plane. We describe a technique that classifies abnormal gait automatically on the basis of sagittal kinematic data. Fifty-five hemiplegic and 91 diplegic patients were analyzed using an opto-electronic scanner (CODA-3). The sagittal kinematics of the affected limb in hemiplegics correlated with those of both affected limbs in diplegics. We introduce the concept of the "plegic limb." Sagittal kinematics of 237 affected limbs were studied using cluster statistical analysis. Eight clear groups emerged. The predominant clinical features, typical of each group, were identified and described (eg, stiff leg gait, genu recurvatum, or crouch gait). We propose this classification system as a new technique to use gait analysis data to automatically classify abnormal movements of the lower limb in cerebral palsy.

Split tibialis posterior tendon transfer in the treatment of spastic equinovarus foot

Sixteen patients with cerebral palsy causing equinovarus deformity were treated surgically. All of these patients underwent preoperative gait analysis by using a CODA-3 motion analyzer. The equinus deformity was assessed by using sagittal kinematics, and in particular, the range of movement of the ankle during stance phase and the maximal dorsiflexion during swing. The varus deformity was assessed by the degree of varus of the foot at prepositioning. The degree of varus was obtained by measuring the angle generated between the plane of progression and a line joining a marker on the heel to a marker on the fifth metatarsal in the transverse plane. All patients underwent split tibialis posterior tendon transfer and, in 13, this was combined with tendo calcaneus lengthening. Clinical assessment and gait analysis repeated 1 year postoperatively confirmed good outcome after split tibialis posterior tendon transfer in combination with gastrocnemius lengthening. This was confirmed by using sagittal kinematic analysis and quantitative assessment of the degree of varus of the foot at the time of prepositioning.

Damage to the superior gluteal nerve after the Hardinge approach to the hip

We studied prospectively 81 consecutive patients undergoing hip surgery using the Hardinge (1982) approach. The abductor muscles of the hip in these patients were assessed electrophysiologically and clinically by the modified Trendelenburg test. Power was measured using a force plate. We performed assessment at two weeks, and at three and nine months after operation. At two weeks we found that 19 patients (23%) showed evidence of damage to the superior gluteal nerve. By three months, five of these had recovered. The nine patients with complete denervation at three months showed no signs of recovery when reassessed at nine months. Persistent damage to the nerve was associated with a positive Trendelenburg test.

Surgical correction of a simian foot

Congenital varus deformity of the first metatarsal can be secondary to the abnormal insertion of abductor hallucis, a space-occupying lesion of the first web space, or hypoplasia of the metatarsal. We report a unique case where all three factors were present in one foot. This was combined with talipes equinovarus, which gave the appearance of a simian or hand-like foot.

Orthopaedic complications following cardiac transplantation

Cardiac transplantation has become the treatment of choice for end stage heart disease. In 1990 2,000 transplants were performed worldwide. Orthopaedic Surgeons will be asked with increasing frequency to evaluate and treat bone and soft tissue problems with these patients. Orthopaedic service at the Mater Hospital has been involved in the follow-up treatment of orthopaedic complications in 46 transplant patients over a six year period. Thirty eight were male and eight were female. The ages were between 12 years and 65 years (mean 44.3). Nine (20%) of these patients developed thirteen orthopaedic complications: A vascular Necrosis of the hip (AVN) (4), Soft tissue infections (3), Osteoporosis (2), Stress Fractures (2), Osteomyelitis (1) and Ostomalacia (1). The mode of presentation, investigation and management of orthopaedic problems particular to these patients is described. Most patients who develop bony complications have had increased doses of steroids for episodes of rejection. This study highlights the special features of this patient population that require modification of the treatment approach such as the need to avoid the drug Erythromycin and the increased risk of AVN of the hip in patients who require high dose steroids.