We observed large differences between pertrochanteric and subtrochanteric fractures regarding management and outcomes. Patients with subtrochanteric fractures were mobilized later and were more likely to remain non-weight bearing. In spite of a better baseline situation, patients with subtrochanteric fractures had worse 30-day outcomes: they became more dependent, needed more re-operations, had worse mobility and had a higher risk of living in an assisted facility. They also showed greater in-hospital mortality, though this difference was lost at 30-day follow-up.
Demographic and baseline data
The demographic characteristics of the patients included in the RNFC were similar to those described by other international registries [3, 6, 7, 9, 11, 12]. Patients with subtrochanteric fractures were 6 months younger, although this difference is not clinically relevant. They had better pre-fracture mobility and less cognitive impairment, and were more likely to live at home than patients with pertrochanteric fractures. Patients treated with anti-resorptive medication before the fracture had higher odds of suffering subtrochanteric fractures than pertrochanteric fractures, even though atypical fractures were excluded from this study. We did not observe any differences regarding fracture type among patients treated with bone-forming agents. These findings are consistent with data described in female Medicare beneficiaries: Wang et al. found that use of oral bisphosphonates increased the risk for subtrochanteric and femoral shaft fractures, but not intertrochanteric fractures . Ng et al. observed a slight increase in non-hip femoral fracture rates (including subtrochanteric fractures) in Olmsted County (USA), despite a decreasing hip fracture incidence .
Both extracapsular hip fracture types had similar involvement of clinical specialists during acute hospitalization; surgical delay, type of anaesthesia and discharge destination were similar for both groups. However, the type of surgery and the post-operative mobilization protocols differed: more subtrochanteric fractures were treated with hip arthroplasties despite the lack of metaphyseal support for the femoral stem. Reasons for the choice of treatment are not registered by the RNFC. Subtrochanteric fractures are more difficult to fix [4, 8], so many surgeons might choose a hip replacement, which offers more mechanical stability, looking for better mobility, early weight bearing and faster recovery. There were 22 patients with a subtrochanteric fracture treated with a hip arthroplasty: 13 of them were performed at three hospitals, known as referral centres for complex hip replacement revision surgery. In certain scenarios and aiming for early weight bearing, they might feel more comfortable replacing than fixing a subtrochanteric fracture.
Over 96% of patients were assessed and/or followed up by geriatricians and/or internal medicine, with nearly 75% only by geriatricians. Nevertheless, there were no differences in assessment by clinical specialists between both groups: the differences in mortality and functional outcome observed could not be justified by differences in medical care. There was no control group to assess the weight of geriatricians and internal medicine in patient care, as there is no hospital involved in the RNFC with only trauma surgeons managing patients with hip fractures. The type of fracture and the type of surgery seem to determine the worse outcomes observed in subtrochanteric fractures, despite a better baseline status and similar surgical delay and anaesthetic management.
Post-operative care and hospital discharge
Total and post-operative length of stay in acute hospitalization was 1 day longer for individuals with subtrochanteric fractures. Although the RNFC does not record data that could account for these differences, there are several possible reasons for this delay: blood loss is higher among patients with subtrochanteric fractures. Limitation of weight bearing hinders discharge to home, increasing length of stay. Furthermore, patients with subtrochanteric fractures were mobilized later.
The longer length of stay observed is in line with Karayiannis’s report: patients treated with cerclage cables/wires (mainly used in subtrochanteric fractures) had a longer length of stay . Bandhari et al. identified predictors for a longer length of stay: admission from a long-term care facility, living at home with support, and advanced age, suggesting we should have observed a longer hospital stay among those with pertrochanteric fractures, when quite the contrary was found. Developing complications was the only predictor for length of stay associated with subtrochanteric fractures .
Patients with subtrochanteric fractures were mobilized later. This could be due to fear of fracture displacement or failure of fixation, where delaying mobilization gives a false sense of security. Shukla et al. reported that up to 40% of subtrochanteric fractures require open reduction . This involves larger incisions, increasing blood loss and post-operative pain . This could also justify the higher post-operative stay and in-hospital mortality for subtrochanteric fractures [12, 24].
Thirty-day follow-up, functional outcome and complication
It is remarkable that patients with subtrochanteric fractures had worse 1-month mobility, despite better pre-fracture mobility. Comparison of pre-fracture and 30-day mobility for each patient showed a greater decline in those with subtrochanteric fractures. Both findings suggest that the functional outcome is worse for patients with subtrochanteric fractures. We found that 22.3% of patients with subtrochanteric fractures (versus 8.9% for pertrochanteric fractures) remained non-weight bearing after 30 days, possibly explaining the higher proportion of patients not returning home after 30 days. If patients with a subtrochanteric fracture could bear weight and be discharged to rehabilitation facilities, they would have a greater chance of returning home and having better functional outcomes. Patients with subtrochanteric fractures had more re-operations, particularly revisions of surgical wounds, which can be explained by a higher proportion of open reductions. Surgical complications and non-unions are more common in subtrochanteric fractures than in fractures of other regions of the femur, especially among patients with poor bone quality, unfavourable fracture patterns or suboptimal placement of internal fixation [1, 5, 25,26,27,28,29].
Nearly 60% of the patients in both groups were sent to an assisted facility. Thirty days after hip fracture diagnosis, patients with a subtrochanteric fracture were more likely to remain in an assisted facility. This is a very serious issue: a large number of patients living independently become dependent and are at risk for institutionalization. Our study found some probable reasons: patients remain non-weight bearing longer and have poorer mobility, which hinders living at home. Several solutions could be applied: improvement of surgical techniques including stronger internal fixation and smaller surgical approaches, specialized surgical teams to treat these more difficult fractures, availability of rehabilitation facilities after acute hospitalization and guidelines for the management of these fractures. Failure to research and provide solutions for the functional deterioration following subtrochanteric fractures may lead to a serious public health problem due to increasing institutionalization, which is likely to increase in the near future. All extracapsular hip fractures are grouped together in registries, but subtrochanteric fractures are different from pertrochanteric fractures: both fractures behave differently, with different baseline characteristics, complication rates and outcomes. A more directed management of subtrochanteric fractures might lead to better outcomes.
Furthermore, the data we present are from right before the coronavirus disease 2019 (COVID-19) pandemic, which might impact the presentation and outcome of hip fractures. COVID-19 infection and a concomitant hip fracture presented worse function, with important repercussions for general health .
Our study has several strengths. We included a large number of patients, which is representative of the country’s population. As Spain has a population similar to that of many other Mediterranean or European countries, these results can be applied to other regions. This is, to our knowledge, the first study providing evidence on the worse clinical and functional outcomes of the subtrochanteric fractures versus pertrochanteric fractures in the geriatric population.
Our study has also several limitations inherent to national registries. First, not collecting variables in more detail limits analysis; more variables could help with interpreting of the results of this study. Second, there is a confounding factor as not all cases are treated the same way in the different hospitals. Third, the RNFC is mainly supported by geriatricians working in trauma units: hospitals with no specialized teams managing patients with hip fractures are not represented. Therefore, we cannot compare their results and weight the importance of the orthogeriatric units managing subtrochanteric fractures. Different risk factors might be responsible for the worse functional outcome of subtrochanteric fractures, including delayed weight bearing or physical deterioration after fracture. Reasons for the indication of non-weight bearing could be poor reduction or unstable fixation, but we were unable to analyse this in greater detail. Future studies should evaluate the influence of delayed weight bearing on functional results, as well as reasons for delayed weight bearing such as quality of reduction, type of fixation or post-operative fracture stability.
In conclusion, pertrochanteric and subtrochanteric fractures in older people are commonly treated similarly. However, geriatricians and orthopaedic surgeons sense that both groups may have different features and outcomes, and our results provide evidence to support this statement. To our knowledge, this is the first study pointing out the differences between extracapsular fractures in older patients. Individuals suffering subtrochanteric fractures are significantly younger, have less cognitive impairment and are more likely to live at home before the fracture, but have a higher risk of remaining non-weight bearing after surgery, with worse functional outcomes, more re-operations and more institutionalization. In-hospital, but not 1-month, mortality was higher. We can thus conclude that, in patients 75 years old and older, subtrochanteric fractures are different from pertrochanteric fractures with a worse prognosis, including higher morbidity, mortality and functional decline. Though both are extracapsular fractures, they should be addressed differently as subtrochanteric fractures present a higher risk of complications.