Abstract
Introduction
Electrolyte imbalance in the elderly is a clinical problem faced by both elderly care physicians and orthopaedic surgeons alike. Hyponatraemia is a common condition with a vague clinical profile and severe consequences if untreated. Recent medical editorials have criticised orthopaedic handling of this problem. We therefore sought to establish the incidence of hyponatraemia within our orthopaedic population and a similar age-matched elderly care population in the light of changing attitudes to fluid management.
Methods
Retrospective, consecutive analysis of the serum sodium concentrations and fluid regimes of all patients admitted with a fractured neck of femur during a three-month period. An age-matched control group of elderly care patients was used for comparison. Data was analysed using paired t-test and independent t-test as appropriate.
Results
200 patients were identified, 100 in each group. There was no loss to follow-up. The mean admission serum sodium of all patients studied was 135.7mmol/L (SD=5.4). Comparison of two groups showed no statistical significant difference between them (t(198)=0.70, p=0.49). The mean follow-up sodium was 136.6mmol/L (SD=4.5). Comparison of two groups again showed no difference (t(198)=0.64, p=0.52). While the mean levels were greater than 135.0mmol/L in both groups the actual percentage of cases presenting to hospital with hyponatraemia were 29% in the hip fracture group and 33% in the elderly care group. This compared poorly with previously quoted levels of approximately 15% elderly admissions in other studies. We also noted that of those patients that were hyponatraemic on admission, the majority remained hyponatraemic during their hospital stay.
Discussion
This study underlines the high incidence of hyponatraemia within the elderly orthopaedic population. It also demonstrates that there is no statistically significant difference in the incidence of hyponatraemia between the elderly orthopaedic population and the general elderly population, both before operative intervention and thereafter.
