Clinical characteristics and short to mid term functional outcomes of surgically treated occult hip fractures in the elderly.

BACKGROUND: Occult hip fractures in the elderly are challenging to diagnose and often result in surgical delays which may worsen outcomes. However, the minimally displaced nature of these fractures may conversely lead to better outcomes. The aim of this study was to determine if surgically treated occult hip fractures have better short to mid term functional outcomes when compared to non-occult fractures. The secondary aim was to determine if there are any differences in clinical characteristics of patients who present with occult hip fractures.

METHODS: This was a retrospective cohort study of all elderly patients aged 65 years and above who presented with hip fractures in a single institution from January 2012 to December 2013. Elderly patients who presented with hip fractures were enrolled into an Ortho-geriatric carepath and were eligible for recruitment. The exclusion criteria included patients with pathological fractures and multiple injuries. Demographic and pre-injury variables were collected. The functional outcome measurement was the Modified Barthel's Index (MBI). Patients were divided into non-occult hip fractures (Group 1) and occult hip fractures (Group 2).

RESULTS: A total of 1017 patients were admitted during this period into the hip fracture carepath, of which 49 (4.8%) were diagnosed to have occult hip fractures. There was no significant difference between the demographics, Charlson co-morbidity index, abbreviated mental test scores or pre-morbid patient dependence between the groups. There was a significant delay to surgery for occult hip fractures when compared to non-occult fractures. (p = 0.03) Subgroup analysis showed that pre-morbidly, patients with occult inter-trochanteric fractures were significantly more independent than patients with non-occult inter-trochanteric fractures. (p = 0.03) There was no significant difference between the length of stay, surgical complications and 1-year mortality between the 2 groups. Occult inter-trochanteric fractures had better MBI scores at all time points when compared to non-occult inter-trochanteric fractures.

CONCLUSIONS: Despite the significant delay to surgical intervention for patients with occult hip fractures, the short to mid term functional outcomes for this group of patients are comparable to surgically treated non-occult hip fractures. There are no distinctive clinical characteristics of elderly patients who are more likely to suffer occult hip fractures.