Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Journal of Orthopaedics https://doi.org/10.1186/s10195-022-00637-8 and Traumatology ORIGINAL ARTICLE Open Access Impact of subtrochanteric fractures in the geriatric population: better pre‑fracture condition but poorer outcome than pertrochanteric fractures: evidence from the Spanish Hip Fracture Registry Héctor J. Aguado1,2* , Pablo Castillón‑Bernal3,4 , Paula S. Ventura‑Wichner5 , María C. Cervera‑Díaz1 , Javier Abarca‑Vegas3, Luis García‑Flórez1 , Jordi Salvador‑Carreño3 , Virginia García‑Virto1 , Clarisa Simón‑Pérez1,2 , Cristina Ojeda‑Thies6 , Pilar Sáez‑López7,8,9 , Juan I. González‑Montalvo7,10,11 and RNFC Working Group Abstract Background: Clinical management in orthogeriatric units and outcome indicators are similar for extracapsular fragil‑ ity hip fractures, without discriminating between subtrochanteric and pertrochanteric fractures. Hypothesis: Geriatric patients, 75 years or older, with subtrochanteric fractures have worse clinical and functional outcomes than those with pertrochanteric fractures. Materials and methods: Retrospective observational study of data prospectively collected by the Spanish Hip Frac‑ ture Registry including patients 75 years or older, admitted for extracapsular hip fractures from January 2017 to June 2019. Demographic and baseline status, pre-operative, post-operative and 30-day follow-up data were included. Results: A total of 13,939 patients with extracapsular hip fractures were registered: 12,199 (87.5%) pertrochanteric and 1740 (12.5%) subtrochanteric. At admission, patients with subtrochanteric fractures were younger (86.5 ± 5.8 ver‑ sus 87.1 ± 5.6 years old), had better pre-fracture mobility (3.7 ± 2.7 versus 3.9 ± 2.8) (1-to-10 scale, 1 being independ‑ ent) and were more likely to be living at home; those with pertrochanteric fractures had worse cognitive function (Pfeiffer 3.3 ± 3.3 versus 3.8 ± 3.5). The subtrochanteric fracture group showed worse post-fracture mobility (7.3 ± 2.7 versus 6.7 ± 2.7) and greater deterioration of mobility (3.7 ± 3.0 versus 2.9 ± 2.7). Among individuals living at home at baseline, those with subtrochanteric fractures were more likely to remain in an assisted facility at 30-day follow-up. In- hospital mortality during acute admission was higher for the subtrochanteric group (5.6% versus 4.5%) (p = 0.028). To our knowledge, this is the first paper highlighting the differences between these two fracture groups in the geriatric population. Conclusions: Subtrochanteric fractures in the older population are a different and worse entity, with greater morbi‑ mortality and functional decline than pertrochanteric fractures. Despite being younger and fitter at admission, older *Correspondence: hjaguado@gmail.com 1 Orthogeriatric Unit, Servicio de Traumatología y Cirugía Ortopédica, Hospital Clínico Universitario, Av. Ramón y Cajal 3, 47003 Valladolid, Spain Full list of author information is available at the end of the article © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 2 of 8 patients with subtrochanteric fractures have a higher risk of remaining non-weight bearing and undergoing re- operation and institutionalization. Orthogeriatric units should be aware of this and manage subtrochanteric fractures accordingly. Level of evidence: IV. Keywords: Aged, Geriatric, Hip fracture, Pertrochanteric, Subtrochanteric, Intertrochanteric, Extracapsular, Registry, Outcome, Complication, Fragility fracture Introduction Of all patients treated in the participating centres, Extracapsular hip (proximal femur) fractures in older 96.5% consented inclusion in the registry. Collaborators patients are clinically managed similarly in ortho- from the included hospitals participate and include data geriatric units and evaluated using the same clinical on a voluntary basis, following approval by local insti- outcomes, without discriminating between subtrochan- tutional review boards. The RNFC is registered in the teric and pertrochanteric fractures. However, surgical Spanish Data Protection Agency [9]. Extracapsular hip treatment of subtrochanteric fractures is more chal- fractures were classified into pertrochanteric or subtro- lenging [1–5]. National hip fracture registries currently chanteric following the definition proposed by Fielding collect data differentiating intra- and extracapsular [15, 16]. Atypical or pathological fractures were excluded fractures, but no further subgroup analysis is per- from this study. formed [2, 3, 5–12]. Evidence supporting differences The RNFC collects data grouped into: in clinical history, outcome and complications between (1) Demographic and baseline data: Age, sex, fracture intertrochanteric and subtrochanteric fractures is type, side, cognitive status, overall health [American scarce [2, 13, 14]. Society of Anesthesiologists (ASA) physical status clas- The subtrochanteric fractures can extend proximally sification system], mobility, place of residence and osteo- (trochanteric or femoral neck) or distally (diaphyseal) protective treatment. Each patient’s pre-fracture mobility [4, 15, 16]. They account for approximately 5–22% of all was graded from 1 to 10, (1 “completely independent extracapsular hip fractures and have a negative effect on gait”, 10 “no mobility at all or with the help of 2 other quality of life and social function [17]. people”) (Table 1). Cognitive status was assessed using Our working hypothesis is that patients in the geriat- Pfeiffer’s Short Portable Mental Status Questionnaire ric population presenting with subtrochanteric fractures [19]. Osteoprotective treatment was defined as either have worse clinical and functional outcomes than those anti-resorptive (i.e. bisphosphonates) or bone-forming with pertrochanteric fractures. Knowledge of the poten- medication. tial differences between both types could raise awareness (2) Operative care: Time from presentation to surgery towards subtrochanteric fractures, reduce complications (days and hours), type of anaesthesia and surgery, and and improve their outcome. physician co-management during acute hospitalization. Surgical treatment is divided into internal fixation (i.e. nails, plates or screws), joint replacement (hemi- or total Materials and methods We performed a retrospective observational study of data prospectively collected by the Spanish Hip Fracture Reg- istry (Registro Nacional de Fracturas de Cadera, RNFC) Table 1 Consensus table grading mobility status from 1 to 10 [10, 18] including all patients diagnosed with extracap- 1 Independent mobility out and at home, without technical aids sular hip fractures from January 2017 to June 2019. The 2 Independent mobility out and at home, with one technical aid RNFC is a multi-centre, observational, prospective audit 3 Independent mobility out and at home, with two technical aids including all patients 75 years or older admitted for hip or walker fractures in any of the 77 participating centres, followed 4 Independent mobility only at home, without technical aids up for 30 days, who provide consent [18], registering 5 Independent mobility only at home, with one technical aid the variables proposed in the Fragility Fracture Network 6 Independent mobility only at home, with two technical aids or Minimum Common Dataset (FFN MCD). All participat- walker ing centres received approval from their local ethics com- 7 Independent mobility only at home, watched by carer or relative mittees, and this study has therefore been performed in 8 Mobility only at home, with little extra help from carer or relative accordance with the ethical standards laid down in the 9 Mobility only at home, with little extra help from carer or relative 1964 Declaration of Helsinki. 10 Mobility with the help of two people or no mobility Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 3 of 8 hip arthroplasty, cemented or uncemented), or non-oper- cognitive function at admission (Pfeiffer 3.3 ± 3.3 versus ative management. 3.8 ± 3.5). (3) Post-operative care: Mobilization on the first post- operative day, total and post-operative length of hospital Operative care: (Table 3) stay, discharge destination, osteoprotective treatment at There were no differences between groups regarding sur- discharge, pressure ulcers and vital status. gical delay (2.8 ± 4.6 versus 3.0 ± 3.4) or type of anaes- (4) Thirty-day follow-up: Mobility (from 1 to 10), osteo- thesia used (neuro-axial 93.6% versus 93.1% or general protective treatment, place of residence, re-admission to 6.4% versus 6.9%) (p = 0.442). Intramedullary nailing was hospital and re-operations within 1 month, difference the main type of internal fixation for both groups, with between baseline and 1-month mobility, and vital status. a minority treated with plates. Only 96 patients (0.7%) Data were analysed using descriptive statistics. Quan- were treated non-operatively. The proportion of fractures titative results are expressed as mean ± standard devia- managed with arthroplasty was higher for subtrochan- tion. Qualitative or dichotomous variables are expressed teric fractures than for pertrochanteric fractures (3.8% in percentages. The chi-squared test was used to com- versus 1.8%). Orthopaedic surgeons performed clinical pare proportions and study the relationships between assessment and follow-up during acute admission, and them. Comparisons between two quantitative variables the proportion with involvement of geriatricians (76.3% were made using Student’s t-test. To evaluate relation- versus 74.6%) and/or internal medicine specialists (19.4% ships, odds ratio (OR) and 95% confidence intervals (95% versus 21.2%) was similar for both groups (p = 0.637). CI) were calculated. The level of significance was set at p < 0.05. All statistical analyses were performed using Post‑operative care and hospital discharge: (Table 4) SPSS v.23 software (IBM, Armonk, NY, USA). Patients with subtrochanteric fractures were less likely to be mobilized on the first post-operative day (p < 0.001). Results Both total and post-operative length of stay were longer A total of 13,939 patients with extracapsular hip fractures for subtrochanteric fractures (p < 0.001). No differences were registered between January 2017 and June 2019: regarding discharge destination could be found between 12,199 (87.5%) had pertrochanteric fractures and 1740 groups (p = 0.572). (12.5%) subtrochanteric fractures. Thirty‑day follow‑up, functional outcome, complications Demographics and baseline data: (Table 2) and mortality rates: (Table 5) Patients with extracapsular hip fractures were predomi- Weight bearing was less likely to be permitted in patients nantly female (76.9%), similarly for pertrochanteric and with subtrochanteric fractures (p < 0.001), who also subtrochanteric fractures. Those admitted for subtro- showed worse post-fracture mobility (p < 0.001), and a chanteric fractures were significantly younger (86.5 ± 5.8 greater deterioration of baseline mobility versus 30-day versus 87.1 ± 5.6 years old), had better pre-fracture mobility (p < 0.001). The proportion of patients liv- mobility (3.7 ± 2.7 versus 3.9 ± 2.8) and were more likely ing in assisted facilities at 1 month was higher among to be living at home than in nursing homes (76.2% versus those with subtrochanteric fractures (p = 0.008). Among 79.4%). Those with pertrochanteric fractures had worse patients living at home before the fracture, those with Table 2 Demographics and pre-fracture status expressed in mean ± standard deviation and percentage Demographics and pre-FX status Pertrochanteric Subtrochanteric OR (95% CI)/p Age* 87.1 ± 5.57 86.5 ± 5.77 < 0.001 Female versus male 76.7% versus 23.3% 78.4% versus 21.6% 0.906 (0.803–1.024)/0.115 Right versus left side 51% versus 49% 51.5% versus 48.5% 0.938 (0.889–1.087)/0.736 Pfeiffer* 3.77 ± 3.45 3.33 ± 3.31 < 0.001 ASA 2.83 ± 0.63 2.84 ± 0.64 0.462 Pre-FX mobility* 3.90 ± 2.76 3.74 ± 2.74 0.025 Living at home before fracture* 76.2% 79.4% 1.198(1.058–1.355)/0.004 Osteoprotective treatment pre-FX:* 5.8% 7.9% 1.391 (1.150–1.683)/0.001 Anti-resorptive* 5.4% 7.3% 1.367 (1.122–1.665)/0.002 Bone forming 0.6% 0.8% 1.313 (0.740–2.328)/0.350 Odds ratio (OR) and 95% confidence intervals (95% CI). *p < 0.05 Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 4 of 8 Table 3 Operative care data expressed in means ± standard deviation and percentages Operative care Pertrochanteric Subtrochanteric OR (95%CI) / p Time (days) to operation 2.78 ± 4.56 2.98 ± 3.37 0.078 Time (hours) to operation 66.28 ± 108.92 69.64 ± 65.99 0.215 Type of anaesthesia General 6.4% 6,9% 1.083 (0.884–1.327)/0.442 Neuro-axial 93,6% 93.1% Surgical Treatment* Fixation 97.5% 96% < 0.001 Joint replacement 1.8% 3.2% Non-operative 0.7% 0.8% Clinical assessment Geriatrician 76.3% 74.6% 0.637 Internal medicine 19.4% 21.2% Both 0.6% 0.5% Only trauma surgeon 3.6% 3.7% Odds ratio (OR) and 95% confidence intervals (95%CI). *p < 0.05 Table 4 Post-operative care data expressed as mean ± standard deviation and percentage Post-operative care Pertrochanteric Subtrochanteric OR (95% CI)/p Out of bed < 24 h post-operation* 64.7% 59.5% 1.252 (1.128–1.389)/< 0.001 Post-operative length of hospital stay (days)* 7.61 ± 5.61 8.49 ± 7.20 < 0.001 Total length of hospital stay (days)* 10.20 ± 6.47 11.32 ± 7.85 < 0.001 Pressure ulcers 6.1% 6.7% 0.349 Hospital discharge: 1.032 (0,928–1.147)/0.563 Own home or family 40.5% 39,7% Healthcare facility 59.5% 60.3% Bone-protective treatment discharge 40.4% 40.4% 1.001 (0.901–1.112)/0.986 Anti-resorptive 38.7% 38.1% 1.026 (0.922–1.141)/0.640 Bone forming 2.5% 3.1% 0.800 (0.591–1.082)/0.147 Odds ratio (OR) and 95% confidence intervals (95% CI). *p < 0.05 subtrochanteric fractures had a higher risk of remaining In a subgroup analysis according to the surgical treat- in an assisted facility at 1 month: 44.5% were unable to ment, there were no differences in mortality at any time return home (OR 37.31, 95% CI 19.67–70.77; p < 0.001) of follow-up (p = 0.545). versus 38.0% for the pertrochanteric group (OR 46.37, 95% CI 37.18–57.83; p < 0.001). Patients with subtrochan- teric fractures were more likely to receive bone-form- Discussion ing medication (p = 0.025). The re-operation rate was We observed large differences between pertrochan- higher among those with subtrochanteric fractures, most teric and subtrochanteric fractures regarding manage- commonly for revision of the surgical wound. Other ment and outcomes. Patients with subtrochanteric indications for re-intervention were: prosthetic hip dislo- fractures were mobilized later and were more likely to cations, failure of internal fixation, and peri-implant frac- remain non-weight bearing. In spite of a better baseline ture (around a prosthesis or an internal fixation device). situation, patients with subtrochanteric fractures had Mortality during acute hospitalization was higher worse 30-day outcomes: they became more dependent, for the subtrochanteric fracture group (p = 0.028) (OR needed more re-operations, had worse mobility and 1.27, 95% CI 1.03–1.59). There were no differences in had a higher risk of living in an assisted facility. They 30-day mortality (subtrochanteric group 91.0% survival also showed greater in-hospital mortality, though this versus 92.1% for the pertrochanteric group) (p = 0.130). difference was lost at 30-day follow-up. Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 5 of 8 Table 5 Thirty-day follow-up data expressed as mean ± standard deviation and percentage Thirty-day follow-up Pertrochanteric Subtrochanteric OR (95% CI)/p Alive at 30-day follow-up 92.1% 91.0% 1.148 (0.960–1.374)/0.130 No weight bearing within 30 days post-operation* 8.9% 22.3% 0.338 (0.256–0.445)/< 0.001 Post-FX mobility (30 days)* 6.66 ± 2.67 7.33 ± 2.71 < 0.001 Pre-FX versus post-FX mobility (30 days)* 2.88 ± 2.69 3.72 ± 2.98 < 0.001 Living at own home after 30 days* 48.3% 44.8% 0.864 (0.775–0.962)/0.008 Living in own home pre-fracture but at healthcare facility after 38.0% 44.5% < 0.001 30 days* Bone-protective treatment: 42.5% 42.3% 1.009 (0.905–1.124)/0.887 Anti-resorptive 39.7% 38.7% 1.046 (0.938–1.168)/0.419 Bone forming* 3.6% 4.8% 0.747 (0.578–0.965)/0.025 Hospital re-admission within 30 days post-operation 3.1% 2.5% 1.206 (0.869–1.673)/0.263 Re-operation < 30 days post-operation* 1.7% 1.9% 0.011 Wound surgical revision* 0.5% 1.1% 2.418 (1.413–4.137)/0.001 Hip arthroplasty dislocation 0.2% 0.1% Failed fixation 0.7% 0.4% Peri-implant fracture 0.1% 0.2% Other reasons 0.2% 0.1% Odds ratio (OR) and 95% confidence intervals (95% CI). *p < 0.05 Demographic and baseline data However, the type of surgery and the post-operative The demographic characteristics of the patients included mobilization protocols differed: more subtrochanteric in the RNFC were similar to those described by other fractures were treated with hip arthroplasties despite international registries [3, 6, 7, 9, 11, 12]. Patients with the lack of metaphyseal support for the femoral stem. subtrochanteric fractures were 6 months younger, Reasons for the choice of treatment are not registered although this difference is not clinically relevant. They by the RNFC. Subtrochanteric fractures are more dif- had better pre-fracture mobility and less cognitive ficult to fix [4, 8], so many surgeons might choose a impairment, and were more likely to live at home than hip replacement, which offers more mechanical stabil- patients with pertrochanteric fractures. Patients treated ity, looking for better mobility, early weight bearing with anti-resorptive medication before the fracture had and faster recovery. There were 22 patients with a sub- higher odds of suffering subtrochanteric fractures than trochanteric fracture treated with a hip arthroplasty: pertrochanteric fractures, even though atypical frac- 13 of them were performed at three hospitals, known tures were excluded from this study. We did not observe as referral centres for complex hip replacement revi- any differences regarding fracture type among patients sion surgery. In certain scenarios and aiming for early treated with bone-forming agents. These findings are weight bearing, they might feel more comfortable consistent with data described in female Medicare ben- replacing than fixing a subtrochanteric fracture. eficiaries: Wang et al. found that use of oral bisphospho- Over 96% of patients were assessed and/or followed nates increased the risk for subtrochanteric and femoral up by geriatricians and/or internal medicine, with nearly shaft fractures, but not intertrochanteric fractures [20]. 75% only by geriatricians. Nevertheless, there were no Ng et al. observed a slight increase in non-hip femoral differences in assessment by clinical specialists between fracture rates (including subtrochanteric fractures) in both groups: the differences in mortality and functional Olmsted County (USA), despite a decreasing hip fracture outcome observed could not be justified by differences incidence [21]. 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 Operative care only trauma surgeons managing patients with hip frac- Both extracapsular hip fracture types had similar tures. The type of fracture and the type of surgery seem involvement of clinical specialists during acute hos- to determine the worse outcomes observed in subtro- pitalization; surgical delay, type of anaesthesia and chanteric fractures, despite a better baseline status and discharge destination were similar for both groups. similar surgical delay and anaesthetic management. Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 6 of 8 Post‑operative care and hospital discharge fracture patterns or suboptimal placement of internal Total and post-operative length of stay in acute hospitali- fixation [1, 5, 25–29]. zation was 1 day longer for individuals with subtrochan- Nearly 60% of the patients in both groups were sent to teric fractures. Although the RNFC does not record data an assisted facility. Thirty days after hip fracture diagno- that could account for these differences, there are several sis, patients with a subtrochanteric fracture were more possible reasons for this delay: blood loss is higher among likely to remain in an assisted facility. This is a very seri- patients with subtrochanteric fractures. Limitation of ous issue: a large number of patients living independently weight bearing hinders discharge to home, increasing become dependent and are at risk for institutionaliza- length of stay. Furthermore, patients with subtrochan- tion. Our study found some probable reasons: patients teric fractures were mobilized later. remain non-weight bearing longer and have poorer The longer length of stay observed is in line with Karay- mobility, which hinders living at home. Several solutions iannis’s report: patients treated with cerclage cables/wires could be applied: improvement of surgical techniques (mainly used in subtrochanteric fractures) had a longer including stronger internal fixation and smaller surgi- length of stay [22]. Bandhari et al. identified predictors cal approaches, specialized surgical teams to treat these for a longer length of stay: admission from a long-term more difficult fractures, availability of rehabilitation care facility, living at home with support, and advanced facilities after acute hospitalization and guidelines for the age, suggesting we should have observed a longer hos- management of these fractures. Failure to research and pital stay among those with pertrochanteric fractures, provide solutions for the functional deterioration follow- when quite the contrary was found. Developing compli- ing subtrochanteric fractures may lead to a serious pub- cations was the only predictor for length of stay associ- lic health problem due to increasing institutionalization, ated with subtrochanteric fractures [23]. which is likely to increase in the near future. All extracap- Patients with subtrochanteric fractures were mobilized sular hip fractures are grouped together in registries, but later. This could be due to fear of fracture displacement subtrochanteric fractures are different from pertrochan- or failure of fixation, where delaying mobilization gives a teric fractures: both fractures behave differently, with false sense of security. Shukla et al. reported that up to different baseline characteristics, complication rates and 40% of subtrochanteric fractures require open reduction outcomes. A more directed management of subtrochan- [5]. This involves larger incisions, increasing blood loss teric fractures might lead to better outcomes. and post-operative pain [22]. This could also justify the Furthermore, the data we present are from right before higher post-operative stay and in-hospital mortality for the coronavirus disease 2019 (COVID-19) pandemic, subtrochanteric fractures [12, 24]. which might impact the presentation and outcome of hip fractures. COVID-19 infection and a concomitant hip Thirty‑day follow‑up, functional outcome and complication fracture presented worse function, with important reper- It is remarkable that patients with subtrochanteric frac- cussions for general health [30]. tures had worse 1-month mobility, despite better pre- Our study has several strengths. We included a large fracture mobility. Comparison of pre-fracture and 30-day number of patients, which is representative of the coun- mobility for each patient showed a greater decline in try’s population. As Spain has a population similar to those with subtrochanteric fractures. Both findings sug- that of many other Mediterranean or European coun- gest that the functional outcome is worse for patients tries, these results can be applied to other regions. This with subtrochanteric fractures. We found that 22.3% of is, to our knowledge, the first study providing evidence patients with subtrochanteric fractures (versus 8.9% for on the worse clinical and functional outcomes of the sub- pertrochanteric fractures) remained non-weight bearing trochanteric fractures versus pertrochanteric fractures in after 30 days, possibly explaining the higher proportion the geriatric population. of patients not returning home after 30 days. If patients Our study has also several limitations inherent to with a subtrochanteric fracture could bear weight and be national registries. First, not collecting variables in more discharged to rehabilitation facilities, they would have a detail limits analysis; more variables could help with greater chance of returning home and having better func- interpreting of the results of this study. Second, there is tional outcomes. Patients with subtrochanteric fractures a confounding factor as not all cases are treated the same had more re-operations, particularly revisions of surgical way in the different hospitals. Third, the RNFC is mainly wounds, which can be explained by a higher proportion supported by geriatricians working in trauma units: hos- of open reductions. Surgical complications and non- pitals with no specialized teams managing patients with unions are more common in subtrochanteric fractures hip fractures are not represented. Therefore, we cannot than in fractures of other regions of the femur, especially compare their results and weight the importance of the among patients with poor bone quality, unfavourable orthogeriatric units managing subtrochanteric fractures. Aguado et al. Journal of Orthopaedics and Traumatology (2022) 23:17 Page 7 of 8 Different risk factors might be responsible for the worse (grant number AP169672018) and Fundación Mapfre. The sponsors were not involved in any aspect of the project or in preparation of the manuscript. functional outcome of subtrochanteric fractures, includ- ing delayed weight bearing or physical deterioration after Availability of data and materials fracture. Reasons for the indication of non-weight bear- The data that support the findings of this study are available from the Spanish Hip Fracture Registry (Registro Nacional de Fracturas de Cadera, RNFC), but ing could be poor reduction or unstable fixation, but we restrictions apply to the availability of these data, which were used under were unable to analyse this in greater detail. Future stud- license for the current study and so are not publicly available. Data are, how‑ ies should evaluate the influence of delayed weight bear- ever, available from the authors upon reasonable request and with permission of Registro Nacional de Fracturas de Cadera, RNFC. ing on functional results, as well as reasons for delayed weight bearing such as quality of reduction, type of fixa- tion or post-operative fracture stability. Declarations In conclusion, pertrochanteric and subtrochanteric Ethics approval and consent to participate fractures in older people are commonly treated similarly. All participating centres in the Spanish hip fracture registry Registro Nacional de Fracturas de Cadera (RNFC) received approval from their local ethics However, geriatricians and orthopaedic surgeons sense committees or local institutional review boards. This study has therefore been that both groups may have different features and out- performed in accordance with the ethical standards laid down in the 1964 comes, and our results provide evidence to support this Declaration of Helsinki. All patients included in the registry (RNFC) gave their prior informed consent. statement. To our knowledge, this is the first study point- ing out the differences between extracapsular fractures Consent for publication in older patients. Individuals suffering subtrochanteric Not applicable. fractures are significantly younger, have less cognitive Competing interests impairment and are more likely to live at home before the Héctor J. Aguado, Pablo Castillón-Bernal, Paula S. Ventura-Wichner, Carmen fracture, but have a higher risk of remaining non-weight Cervera-Díaz, Javier Abarca-Vegas, Luis García Flórez, Jordi Salvador-Carreño, Virginia García-Virto, Clarisa Simón-Pérez, Cristina Ojeda-Thies, Pilar Sáez-López bearing after surgery, with worse functional outcomes, and Juan I. González-Montalvo have no personal or commercial association more re-operations and more institutionalization. In- (e.g. consultancies, stock ownership, equity interest, patent, licensing arrange‑ hospital, but not 1-month, mortality was higher. We can ments, etc.) that might pose a conflict of interest in connection with the submitted article. The authors declare that they have no competing interests. thus conclude that, in patients 75 years old and older, subtrochanteric fractures are different from pertrochan- Author details teric fractures with a worse prognosis, including higher 1 Orthogeriatric Unit, Servicio de Traumatología y Cirugía Ortopédica, Hospital Clínico Universitario, Av. Ramón y Cajal 3, 47003 Valladolid, Spain. 2 Univer‑ morbidity, mortality and functional decline. Though both sidad de Valladolid (UVA), Valladolid, Spain. 3 Trauma Department, Hospital are extracapsular fractures, they should be addressed dif- Universitari Mútua de Terrassa Plaza Dr, Robert 5, 08221 Terrasa, Barcelona, ferently as subtrochanteric fractures present a higher risk Spain. 4 Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain. 5 Fundación de Investigación HM Hospitales & Fundació Institut d’Investigació of complications. en Ciències de la Salut Germans Trias i Pujol (IGTP), Barcelona, Spain. 6 Depart‑ ment of Traumatology and Orthopaedic Surgery, Hospital Universitario 12 de Octubre, Madrid, Spain. 7 Instituto de Investigación del Hospital La Paz, IdiPAZ, Abbreviations Madrid, Spain. 8 Department of Geriatrics, Hospital Universitario Fundación RNFC: Registro Nacional de Fracturas de Cadera, The Spanish Hip Fracture Reg‑ Alcorcón, Madrid, Spain. 9 Head Coordinator of the Spanish National Hip istry; FFN MCD: Fragility Fracture Network Minimum Common Dataset; ASA: Fracture Registry, Madrid, Spain. 10 Geriatric Medicine Department, Hospital American Society of Anesthesiologists; OR: Odds ratio; CI: Confidence interval. Universitario La Paz, Madrid, Spain. 11 Department of Medicine, Universidad Autónoma de Madrid, Madrid, Spain. Supplementary Information Received: 7 December 2021 Accepted: 26 February 2022 The online version contains supplementary material available at https://​doi.​ org/​10.​1186/​s10195-​022-​00637-8. Additional file 1. List members of the RNFC working group. References 1. Dziadosz D (2015) Considerations with failed intertrochanteric and sub‑ Acknowledgements trochanteric femur fractures: how to treat, revise, and replace. J Orthop Not applicable. Trauma 29(Suppl 4):S17-21. https://​doi.​org/​10.​1097/​BOT.​00000​00000​ List of RNFC members in Additional file 1. 000289 2. Frost SA, Nguyen ND, Center JR, Eisman JA, Nguyen TV (2013) Excess Authors’ contributions mortality attributable to hip-fracture: a relative survival analysis. 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