James D. Hutchison

Osteoarthritis as a systemic disorder including stromal cell differentiation and lipid metabolism

For many years articular cartilage has been the focus of research aimed at improving understanding of and treatment for osteoarthritis. Although much is known about the tissue, research has had little success in elucidating the pathogenesis of generalised osteoarthritis. A new hypothesis is required. Substantial changes in many tissues, including bone, muscle, ligaments, and joint capsule, as well as cartilage, are increasingly recognised in this disease, and not all these changes are localised to the affected joints. There is also a well established link with obesity. These observations, the common origins of the mesenchymal cells that maintain these tissues, and the possible role of neuroendocrine factors that can regulate bone mass, result in the hypothesis that systemic factors that include altered lipid metabolism could explain the diversity of physiological changes in generalised osteoarthritis. If proven, this hypothesis could have important implications for a new approach to pharmacological intervention in the early stages of the disease.

Gender differences in epidemiology and outcome after hip fracture: EVIDENCE FROM THE SCOTTISH HIP FRACTURE AUDIT

We report gender differences in the epidemiology and outcome after hip fracture from the Scottish Hip Fracture Audit, with data on admission and at 120 days follow-up from 22 orthopaedic units across the country between 1998 and 2005. Outcome measures included early mortality, length of hospital stay, 120-day residence and mobility. A multivariate logistic regression model compared outcomes between genders. The study comprised 25 649 patients of whom 5674 (22%) were men and 19 975 (78%) were women. The men were in poorer pre-operative health, despite being younger at presentation (mean 77 years (60 to 101) vs 81 years (50 to 106)). Pre-fracture residence and mobility were similar between genders. Multivariate analysis indicated that the men were less likely to return to their home or mobilise independently at the 120-day follow-up. Mortality at 30 and 120 days was higher for men, even after differences in case-mix variables between genders were considered.

Changes in population demographics and the future incidence of hip fracture

BACKGROUND During the first three decades of the 21st century the combination of increasing life expectancy and falling birth rates will result in substantial demographic changes within the population of the United Kingdom. A large increase in the elderly population is likely to have significant effects on the number of patients who sustain a hip fracture. AIM To predict future changes in hip fracture burden in Scotland. MATERIALS AND METHODS Data was obtained from the Scottish Hip Fracture Audit database for a 12 month period between April 2004 and March 2005. All orthopaedic units in Scotland participated in the audit during this period. This data was used to calculate the incidence of hip fracture by 5 year age/gender cohorts. Outcome data was analysed in a similar manner. Population prediction data obtained from the Registrar Generals Office was then used to predict hip fracture numbers for the year 2031. Two separate prediction models were used. The first model assumed that the age/gender specific incidence of hip fracture observed in 2004 would remain constant. Between 1999 and 2004, a 9.6% decrease in the population incidence of hip fracture was observed. Therefore a second prediction model was used which assumed a continuation in the fall in population incidence of hip fracture between 2004 and 2031. RESULTS The population aged 50 years and above is predicted to increase 28% by 2031, with the most significant increases occurring in the over 1980s. The number of hip fractures is predicted to rise by 45% to 75% (from 6164 to 8829-10756 cases per annum) requiring an additional 287-474 hospital beds. By 2031 approximately 45% of fractures will occur in those aged 85 years and above, compared to 34% in 2004. Predicted changes in population demographics are highly variable by region and so local planning of resource provision will be essential. CONCLUSION Changes in population demographics will have significant implications for health care provision for the care of hip fracture patients. An increase in the capacity of acute orthopaedic care and a review of care models will be required to ensure adequate resource provision.

Outcome After Surgery for the Treatment of Hip Fracture in the Extremely Elderly

BACKGROUND As a consequence of changes in population demographics, the extremely elderly represent one of the fastest growing groups in Western society. Previous studies have associated advanced age with increased mortality after hip fracture; however, this finding has not been consistent. METHODS The Scottish Hip Fracture Audit is a prospective, national, multicenter study that collects data on patients over the age of fifty years who are admitted to the hospital with a hip fracture. For the present study, we used data collected from twenty-two acute-care orthopaedic units between January 1998 and December 2005. The extremely elderly cohort consisted of 919 individuals with an age of ninety-five years or more. Case-mix variables and outcomes were compared with those for a modal control group of 15,461 individuals who were seventy-five to eighty-nine years of age. Outcome measures included thirty and 120-day mortality rates, the length of the hospital stay, the place of residence, and mobility. A multivariable logistic regression model was used to compare outcomes between groups while controlling for significant case-mix variables. RESULTS The extremely elderly presented with poorer indicators of health status as demonstrated by higher American Society of Anesthesiologists scores. In addition, this group was less likely to be independently mobile and more likely to be in institutional care at the time of the fracture (p < 0.001). Mortality at thirty and 120 days was higher in the extremely elderly even after adjusting for case-mix variables. The extremely elderly also were less likely to return home or to return to previous levels of mobility. CONCLUSIONS Although the extremely elderly exhibited a higher prevalence of prefracture indicators of poor outcome, statistical control for these case-mix variables showed further age-related deterioration in survival and outcomes after surgery for the treatment of a hip fracture.

Association Between COLIA1 Sp1 Alleles and Femoral Neck Geometry

Genetic factors play an important role in the pathogenesis of osteoporosis by affecting bone mineral density and other predictors of osteoporotic fracture risk such as ultrasound properties of bone and skeletal geometry. We previously identified a polymorphism of a Sp1 binding site in the Collagen Type 1 Alpha 1 gene (COLIA1) that has been associated with reduced BMD and an increased risk of osteoporotic fractures in several populations. Here we looked for evidence of an association between COLIA1 Sp1 alleles and femoral neck geometry. The study group comprised 153 patients with hip fracture, and 183 normal subjects drawn at random from the local population. Femoral neck geometry was assessed by analysis of pelvic radiographs in the fracture patients and DXA scan printouts in the population-based subjects. The COLIA1 genotypes were detected by polymerase chain reaction and were in Hardy Weinberg equilibrium: “SS” 4 222 (66%); “Ss” 4 105 (31.3%); and “ss” 49 (2.7%). There was no significant difference in hip axis length or femoral neck width between the genotype groups, but femoral neck-shaft angle was increased by about 2° in the Ss/ss genotype groups (n 4 114) when compared with SS homozygotes (n 4 222) (P 4 0.001). Previous studies have suggested that an increased femoral neck-shaft angle may increase the risk of hip fracture in the event of a sideways fall by influencing the forces that act on the femoral neck. The association COLIA1 genotype and increased femoral neck angle noted here may therefore contribute to the BMD-independent increase in hip fracture risk noted in previous studies of individuals who carry the ‘s’ allele.

Change in long-term mortality associated with fractures of the hip: EVIDENCE FROM THE SCOTTISH HIP FRACTURE AUDIT

We investigated the excess mortality risk associated with fractures of the hip. Data related to 29 134 patients who underwent surgery following a fracture of the hip were obtained from the Scottish Hip Fracture Audit database. Fractures due to primary or metastatic malignancy were excluded. An independent database (General Register Office (Scotland)) was used to validate dates of death. The observed deaths per 100 000 of the population were then calculated for each group (gender, age and fracture type) at various time intervals up to eight years. A second database (Interim Life Tables for Scotland, Scottish Government) was then used to create standardised mortality ratios. Analysis showed that mortality in patients aged > 85 years with a fracture of the hip tended to return to the level of the background population between two and five years after the fracture. In those patients aged < 85 years excess mortality associated with hip fracture persisted beyond eight years. Extracapsular hip fractures and male gender also conferred increased risk.

Prevalence, Incidence and Etiology of Hyponatremia in Elderly Patients with Fragility Fractures

Introduction Hyponatremia (serum sodium<135 mMol/L) is the commonest electrolyte imbalance encountered in clinical practice. It is associated with multiple poor clinical outcomes including increased mortality, longer hospital stay, falls and fractures. Prevalence is higher in frail patient groups, and elderly patients with fragility fractures (EPFF) are particularly susceptible. Euvolemic hyponatremia due to syndrome of inappropriate anti-diuretic hormone (SIADH) is widely assumed to be the commonest cause. However, little is known about the epidemiology and etiology of hyponatremia in EPFF. This study established prevalence, incidence and etiology of hyponatremia in EPFF. Methods Prospective observational study of consenting adults aged ≥65 years admitted with a fragility fracture to a university hospital between 7th January and 4th April 2013. Prevalence of hyponatremia on admission and incidence of cases developing in hospital were reported. Etiology of cases of hyponatremia was determined by consensus of an expert panel using pre-specified data collected daily. Results 127/212 (60%) EPFF were recruited (mean age 79 yrs, 78% female). Two participants withdrew mid-study. Of those not recruited, 66 had incapacity to consent and 19 refused participation. Point prevalence of hyponatremia on admission was 13.4% and a further 12.6% developed hyponatremia during admission. Hypovolemic hyponatremia was predominant (70%). 73% of cases were multi-factorial in etiology. The commonest potentially causative factors in cases of hyponatremia were thiazide diuretics (76%), dehydration (70%), proton pump inhibitors (70%), SIADH (27%) and mirtazapine (15%). Conclusion Hyponatremia is highly prevalent in EPFF, seen in 26% of cases. Dehydration and prescription of thiazide diuretics and proton pump inhibitors were the commonest potentially causative factors, not SIADH.

Epidemiology and outcome after hip fracture in the under 65s—Evidence from the Scottish Hip Fracture Audit

AIM To report the epidemiology and outcomes after hip fractures in the patients under 65 years of age. PATIENTS AND METHODS We performed a prospective, multi-centre observational study using the Scottish Hip Fracture Audit Database. Case-mix, process and outcome data was collected by dedicated coordinators on site at the time of admission, at 120 days after the injury and on any re-operations within 12 months. The study cohort consisted of 1896 individuals aged 50-64 years. Patient variables and outcomes were compared to a control group of 15,461 individuals aged 75-89 years of age. The control group consisted of three modal 5-year age groups centred about a median age of 83 years, equal to the database value, excluding the effects of the extreme elderly who may act as confounders. Outcomes measures included 30- and 120-day mortality, length of hospital stay, place of residence and ambulatory status. A multivariate logistic regression model was used to compare outcome between groups while controlling for significant case-mix variables. RESULTS Patients in the study cohort presented with lower ASA scores and were more likely to be independently mobile and live in their own home at the time of fracture (p<0.001). Pathological fractures were more common in younger patients and accounted for more than 1 in 20 fractures. Mortality at 30 and 120 days was significantly lower (p<0.0001) in the study cohort, however it was increased compared to age and gender adjusted mortality rates for the general population (p<0.001) Younger patients were more likely to recover independent mobility and living. CONCLUSION Patients aged 50-64 years have significantly better outcome measures after surgery for hip fracture in terms of survival and function. Such differences exist even after controlling for differences in patient case-mix variables.

Serious neck injuries in U19 rugby union players: an audit of admissions to spinal injury units in Great Britain and Ireland

Objectives To obtain data regarding admissions of U19 rugby players to spinal injury units in Great Britain and Ireland and to compare this with a recent peak in presentation in Scotland. To assess the current state of data collection and subsequent analysis of serious neck injuries. To analyse the mechanism of injury in this group of at-risk players. Design Retrospective case series. Participants Spinal injury units in Great Britain and Ireland. Outcome measures Annual frequency of serious neck injuries. Analysis of injury types, neurological deficit and mechanism of injury. Results 36 Injuries were recorded. 10 Of these occurred in Scotland since 1996 of which six have occurred in the past 4 years. This compared with 14 in Ireland over the same period. 12 Cases were traced in England and Wales since 2000; records were not available before this date. No prospective collation of data is performed by the home unions and inconsistency of data collection exists. The mean age was 16.2 years. 16 Of the 36 admissions had complete neurological loss, 9 had incomplete neurological injury and 11 had cervical column injury without spinal cord damage. The mechanism of injury was tackle in 17 (47%), scrum in 13 (36%), two each due to the maul and collision, and one each due to a kick and a ruck. Some degree of spinal cord injury occurred in 92% of scrum injuries (61% complete) and 53% of tackle injuries (29% complete). Conclusion U19 rugby players continue to sustain serious neck injuries necessitating admission to spinal injury units with a low but persistent frequency. The recent rate of admission in Scotland is disproportionately high when the respective estimated playing populations are considered. While more injuries were sustained in the tackle, spinal cord injury was significantly more common in neck injury sustained in the scrum (p<0.001). No register of catastrophic neck injuries exists despite repeated calls over the past three decades, and a study such as this has not been reported before. Data collection of this serious category of injury is incomplete and very variable across the home unions, as a consequence a large proportion of the serious neck injuries that have occurred in U19 players over the past 14 years have not been analysed. Rigorous data collection and analysis have to be established so that problem areas of the game such as scrum engagement and the tackle can be made safer.

Optimizing the configuration of cement keyholes for acetabular fixation in total hip replacement using Taguchi experimental design.

Abstract Cement fixation of the acetabular component is increasingly recognized as a common site of loosening when hip replacements fail. Cement keyholes drilled into the acetabulum have been recommended to improve this fixation but little is known of the optimum positions or sizes of these holes. This study investigates the diameter, depth and number of keyholes to be drilled to maximize the failure torque in a model system. A Taguchi experimental design was used to identify the most significant factors and to predict the best configuration of keyholes within the constraints of the experimental test rig. One hole at each of the pubic, iliac and ischial sites, of 12 mm diameter and 6 mm depth, was found to be the optimum configuration. The failure torque was most strongly dependent on the hole diameter in the pubic region, decreased with increasing hole depth and was not sensitive to the number of holes.