Abstract
Background
Early mobilization to promote functional recovery and reduce the adverse effects of immobilization is one of the main goals of acute postoperative management of hip fracture (HF). The primary objective of this study was to assess, in usual care, the association between the use of a bodyweight-supported treadmill (BWST) and early postoperative walking recovery in older adults after hip fracture surgery. Secondary objectives were to evaluate delays to first sitting and first walking, daily walking distances, functional outcomes, length of stay, discharge destination, mortality, and the safety of BWST-based rehabilitation.
Methods
We conducted a retrospective cohort study in our perioperative geriatric care unit in Pitié-Salpêtrière hospital, Paris, enrolling all consecutive patients aged 
70 years with HF who were admitted to the unit within 48 h after surgery from September 2021 to October 2023. In January 2023, the unit was equipped with a BWST, and patients received daily walking rehabilitation sessions exclusively using the BSWT instead of the previous conventional rehabilitation sessions.
Results
We included 138 patients (mean [
SD] age 87 [
6.6] years), 101 (73%) were female, the median age-adjusted Charlson Comorbidity Index (CCI) was 7 (interquartile range 5–9), and the median Activities of Daily Living (ADL) score was 5.5 (3.5-6.0); 48 (35%) received BWST training. On univariate analysis, BWST use was significantly associated with earlier first sitting (p = 0.03) and first walking (p < 0.001), greater walking distances at day 1 and day 6 (p < 0.001), greater difference in walking distance between day 1 and day 6 (p < 0.001), and reduced morphine use at discharge (p = 0.006) as compared with the standard rehabilitation care. After adjustment on CCI, ADL, and time between surgery and unit admission (multivariate mixed model), BWST rehabilitation was still positively associated with daily measured walking distances (β = 3.31, 95% CI [2.47;4.16]).
Conclusions
The use of a BWST was significantly associated with improved walking ability in the early postoperative care after HF surgery among older adults. Future interventional studies of larger cohorts are needed to confirm these findings.
Trial registration
Not applicable.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12877-026-07099-1.
Keywords: Hip fracture, Orthogeriatrics, Body weight-supported treadmill, Walking recovery
Background
Hip fracture (HF), a common consequence of falls among older adults, is a major public health concern with poor vital and functional outcomes [1, 2]. Although decreasing in incidence, its prevalence is increasing, with up to 1.6 million cases reported annually worldwide, reflecting the aging global population [2, 3]. In the 12 months after HF, individuals have increased risk of cognitive and functional decline, institutionalization and mortality [4–6]. Only 40% to 60% of HF survivors recover their pre-fracture mobility, and 40% to 70% regain their level of independence for basic activities of daily living [6].
For older adults, prolonged immobilization during hospitalization is the most predictable and preventable cause of loss of independent ambulation [7]. Despite recent international guidelines encouraging proactive early and frequent mobilization after HF surgery [8, 9], recent studies have shown that older people with HF spent greater than 80% of their hospitalization time bedridden [7, 10]. This gap between recommendations and practice underscores the urgent need to improve acute and post-acute care following HF surgery, as emphasized by a recent international collaboration [11].
Early mobilization is crucial in postoperative acute care, with various strategies proposed to promote movement and walking [12]. A recent meta-analysis highlighted that interventions in the in-hospital setting that include training of gait, balance exercises and functional tasks practice were effective in increasing mobility [12]. However, significant barriers to optimal acute rehabilitation persist: staffing or time constraints, low patient engagement and, consequently, low team engagement due to patient pain and postoperative complications resulting in difficulties in mobilization [13, 14].
The contribution of emerging technologies working on balance, walking and cognitive functions can potentially improve rehabilitation outcomes by enhancing patient and physiotherapist involvement. Among these, innovative treadmill training was found feasible and well received by older adults recovering from a fall-related HF [15, 16].
The primary objective of this study was to assess the association between the use of a connected bodyweight-supported treadmill (BWST) and early postoperative walking recovery in older adults hospitalized in a dedicated perioperative geriatric care unit after HF surgery. Secondary objectives were to evaluate delays to first sitting and first walking, daily walking distances, functional and clinical outcomes, length of stay, discharge destination, mortality, and the safety of BWST-based rehabilitation.
Methods
This study received a favorable opinion from the Ethics Committee of Gérond’if (CEGIF) in Paris on December 2, 2024 (registration No. 122024). The database was declared to the French National Commission for Information Technology and Civil Liberties (CNIL) of Assistance Publique-Hôpitaux de Paris (AP-HP) for this study (No. 20190822165316). In accordance with French regulations for observational studies using routine care data, written informed consent was not required. However, all patients or their legal representatives were informed of the database and had the right to object to the use of their data for research purposes. This report follows the STROBE recommendations [17].
Study design, setting and participants
This retrospective observational study was conducted using data extracted from a prospectively maintained institutional orthogeriatric database implemented as part of routine clinical care in the perioperative geriatric care unit (UPOG) of Pitié-Salpêtrière hospital, a university hospital of the AP-HP, Paris. The study comprised two temporally distinct phases. The standard care group (from September 2021 to December 2022) corresponds to a historical cohort analyzed retrospectively, during which patients received conventional postoperative physiotherapy. From January 2023 to October 2023, following the introduction of the BWST, patients received BWST-based rehabilitation as part of routine care, and data for this group were collected prospectively. No other changes in usual care, medical management, rehabilitation goals, staffing, or clinical protocols occurred between the two study periods, apart from the introduction of the BWST.
This unit is part of a dedicated orthogeriatric care pathway including coordination between departments of emergency medicine, surgery, anesthesiology and critical care, geriatrics and rehabilitation. This dedicated orthogeriatric care pathway is defined as follows: (1) early alert from the emergency department (ED); (2) prompt consideration of HF as an emergency surgical case; (3) rapid transfer to the UPOG after surgery; and (4) rapid transfer of stable patients to a dedicated rehabilitation unit [18]. The management strategy in our UPOG, previously described [18], focuses on early mobilization with the aim of chair-sitting and walking within 24 h after admission, alongside pain management, pressure ulcer prevention, detection of swallowing disorders, malnutrition and postoperative complications such as delirium, anemia and atrial fibrillation.
Inclusion and exclusion criteria described below and illustrated in the flow chart were applied specifically for the present study and not for the constitution of the database itself. Patients who refused the secondary use of their routinely collected data were excluded from the analysis. From September 2021 to October 2023, all consecutive patients admitted to the UPOG after HF surgery were screened for eligibility. Patients were included if they were 
70 years old and admitted for HF (first hospitalization in our unit). We excluded those with multiple, metastatic or periprosthetic fractures; patients not walking before the fracture; patients admitted > 48 h after surgery (to ensure accurate postoperative walking distance measurement); and patients who refused the use of their data. Patients were followed until death or 30 days after surgery, whichever occurred first.
Rehabilitation
Throughout the entire study period, rehabilitation was delivered in the same perioperative geriatric care unit by a single senior physiotherapist, permanently assigned full-time to the unit and providing rehabilitation sessions five days per week. This organization applied to both the standard care and BWST periods, ensuring continuity of care and consistency in rehabilitation practices, with the rehabilitation modality being the only difference between cohorts.
From September 2021 to December 2022, standard postoperative rehabilitation was provided by the same physiotherapist. Each patient, when their physical condition allowed it, had one 30-min rehabilitation session daily from Monday to Friday. These sessions included range of motion exercises, muscular strengthening and autonomy-focused exercises using equipment such as transfer handlebars and walking aids.
Since January 2023, we enhanced our usual care protocol, and our unit acquired a connected BWST treadmill for functional rehabilitation (Ema; EzyGain, Paris, France). The treadmill, designed for standing, walking, and balance training, is equipped with a standing system, access ramp, connected tablet, and safety harness. The harness aids users standing from a wheelchair, reduces the patient’s weight from 0% to 100%, and ensures safety during walking. With the tablet, the physiotherapist can adjust settings and monitor the user’s real-time performance. Starting in January 2023, patients received 30-min daily walking sessions exclusively with the BWST under physiotherapist guidance.
Outcomes
Our main outcome was the difference in walking distance with a walking aid between day 1 and day 6 after admission to the UPOG.
Secondary outcomes were delays to first sitting and first walking, daily walking distance after admission to the UPOG measured with a walking aid or treadmill, difference in walking distance with a walking aid between day 1 and day 6 after admission to the UPOG in patients with dementia or those > 85 years old, length of stay (LOS) in acute care, destination at discharge, in-hospital and 30-day mortality and Short Physical Performance Battery (SPPB) score at 6 days. We also evaluated tolerance and safety of the BWST, assessed as part of routine clinical care during rehabilitation sessions. Adverse events were defined as any untoward medical occurrence potentially related to BWST use, including falls, harness-related injuries, discomfort during use, or clinically significant increases in pain leading to session interruption or modification.
In addition, predefined subgroup analyses were performed to compare the difference in walking distance between day 1 and day 6 in patients with dementia and in those aged > 85 years.
Data collection
Since the opening of the UPOG in 2009, we have created a dedicated research database that is prospectively implemented by 3 senior geriatricians (JB, JC-B, LZ), experts in orthogeriatrics, and that integrates all the data from the orthogeriatric care pathway for each patient.
Baseline characteristics before HF were collected prospectively during the hospital stay through interviews with patients, family members and healthcare providers, including age, sex, living conditions (home or nursing home), walking ability, previous medical history, chronic medications and type of fracture (radiological definition by an orthopedic surgeon). Co-morbidity severity and functional status were assessed prospectively by one of the 3 senior geriatricians during the hospital stay. Co-morbidity severity was assessed with the age-adjusted Charlson Comorbidity Index (CCI) [19], and functional status was evaluated with Katz’s index of Activities of Daily Living (ADL) [20] and the 4-item Instrumental Activities of Daily Living (IADL) scale [21]. During the perioperative period, we prospectively recorded the surgical treatment, the delay and duration of the surgery, the anesthetic drugs used and all drugs and transfusions administered from the ED to the UPOG. After surgery, delays to first sitting and first walking, walking distances at day 1 and day 6 with a walking aid, daily walking distances from day 2 to day 5 with a walking aid or the treadmill, SPPB scores [22], destination (home or rehabilitation) at discharge from the UPOG, LOS in acute care and all postoperative complications were prospectively recorded. Surviving patients were seen in routine consultation at 30 days after surgery.
Walking distance assessment is part of routine clinical care in the perioperative geriatric care unit and has been consistently implemented since the opening of the unit in 2009. Walking distances were assessed during rehabilitation sessions by the same senior physiotherapist for both cohorts, who is permanently assigned to the unit five days per week. On day 1 and day 6 after admission to the unit, walking distances were systematically measured in the unit corridor using standardized floor markings placed every five meters. From day 2 to day 5, walking distances were measured either in the same corridor setting or, for patients in the BWST group, based on the distance automatically recorded by the treadmill during rehabilitation sessions. In the rare cases of physiotherapist absence (e.g. holidays), rehabilitation sessions were conducted using the same predefined corridor markings, ensuring standardized and reproducible walking distance measurements. Walking distance data were entered into the research database by senior geriatricians (JB, JC-B, LZ) who were not involved in the rehabilitation care.
Tolerance and safety data were systematically monitored during each rehabilitation session and documented in the medical record; any adverse event was discussed during daily multidisciplinary team meetings.
Statistical analysis
The statistical plan of the study was established before the statistical analysis. Quantitative variables, described with mean (
SD) or median (interquartile range [IQR]), were compared by unpaired Student t test or Mann-Whitney test according to data normality graphically assessed. Categorical variables, described with number (%), were compared by chi-squared or Fisher’s exact test.
A linear mixed model was used to assess factors associated with daily walking distance during the first six days after admission to the perioperative geriatric care unit. Covariates included as fixed effects were selected a priori based on clinical relevance and evidence from the literature, while limiting the risk of overfitting [23–25]. These included baseline functional status (ADL score), comorbidity burden (CCI), delay between surgery and admission to the unit, and BWST use. An interaction term between time and BWST use was included to assess differences in walking distance trajectories over time. Although some variables showed p-values < 0.20 in univariate analyses, only baseline variables considered clinically relevant confounders were retained in the final model [26]. Age was not included separately as it is incorporated into the age-adjusted Charlson Comorbidity Index [27]. Postoperative complications were not included as covariates because they may represent intermediate variables on the causal pathway between rehabilitation and functional recovery [28]. Patient was included as a random effect.
Subgroup analyses in patients with dementia and in those aged > 85 years were exploratory and were performed using univariate analyses only, given the limited sample size in each subgroup and the risk of overfitting multivariable models [23, 24].
Statistical analyses were performed with R Studio 2023.03.1 + 446. All p-values were two-tailed and p < 0.05 was considered statistically significant. We did not adjust p-values for multiple comparisons [29].
Results
A total of 138 patients were included (Fig. 1), of whom 48 (35%) received rehabilitation with the BWST. Baseline characteristics were similar between excluded patients (n = 124) and included patients (Supplementary Material 1).
Fig. 1.
Flow chart of participants in the study. Abbreviations: UPOG: perioperative geriatric care unit; BWST: bodyweight-supported treadmill rehabilitation
Demographic data, baseline characteristics, perioperative data and postoperative complications are summarized in Table 1. The mean (
SD) age of participants was 87 (
6.6) years, 101 (73%) were female; the median CCI was 7 (IQR 5–9) and the median ADL score was 5.5 (3.5–6.0.5.0). Patients with and without BWST rehabilitation did not differ in baseline characteristics or medical history.
Table 1.
Demographic data, baseline characteristics and perioperative data of older patients by type of rehabilitation
| Total (n = 138) | Standard care (n = 90) | BWST (n = 48) | p-value | |
|---|---|---|---|---|
| Demographic data | ||||
Age (years), mean ( ) |
87 ( 6.6) |
88 ( 6.1) |
86 ( 7.4) |
0.18 |
| Male, n (%) | 37 (27) | 25 (28) | 12 (25) | 0.84 |
| Medical history n(%) | ||||
| CCI | 7 (5–9) | 7 (5–9) | 7 (6–9) | 0.94 |
| Dementia1 | 74 (54) | 48 (53) | 26 (54) | 0.99 |
| Depression | 47 (34) | 31 (34) | 16 (33) | 0.99 |
| Stroke | 35 (25) | 24 (27) | 11 (23) | 0.69 |
| Hypertension | 97 (70) | 63 (70) | 34 (71) | 0.99 |
| Atrial fibrillation | 38 (28) | 25 (28) | 13 (27) | 0.99 |
| Cardiac failure | 35 (25) | 25 (28) | 10 (21) | 0.42 |
| Coronary artery disease | 22 (16) | 14 (16) | 8 (17) | 0.99 |
| Thromboembolic disease | 13 (9.4) | 10 (11) | 3 (6.3) | 0.54 |
| Diabetes | 25 (18) | 18 (20) | 7 (15) | 0.49 |
| Chronic kidney disease2 | 81 (59) | 49 (54) | 32 (67) | 0.20 |
| COPD | 11 (8.0) | 6 (6.7) | 5 (10) | 0.51 |
| Cancer | 30 (22) | 21 (23) | 9 (19) | 0.67 |
| Number of drugs per day | 6 (4–8) | 6 (4–8) | 6 (4–8) | 0.65 |
| Baseline functional ability | ||||
| ADL, median (IQR) | 5.5 (3.5–6.0.5.0) | 5.5 (3.5–6.0.5.0) | 5.5 (3.0–6.0) | 0.52 |
| IADL3, median (IQR) | 1 (0–4) | 1 (0–3) | 2 (0–4) | 0.83 |
| Living in institution, n (%) | 18 (13) | 11 (12) | 7 (15) | 0.79 |
| Living at home with assistance, n (%) | 116 (84) | 76 (84) | 40 (83) | 0.99 |
| Walking with assistance, n (%) | 95 (69) | 62 (69) | 33 (69) | 0.99 |
| Repeated falls4, n (%) | 79 (57) | 53 (59) | 26 (54) | 0.72 |
| Surgery | ||||
| Time to surgery (hr)5, median (IQR) | 41 (21–72) | 41 (20–72) | 41 (22–72) | 0.66 |
| Missing values | 1 (0.7) | 0 (0) | 1 (2.1) | |
Duration of surgery (min), mean ( ) |
137 ( 44.5) |
137 ( 47.4) |
139 ( 38.7) |
0.80 |
| Missing values | 3 (2.2) | 1 (1.1) | 2 (4.2) | |
| Time from surgery to UPOG (hr)6, median (IQR) | 6.3 (1.8–24) | 8.9 (2.5–26) | 3.7 (0–22) | 0.05 |
| Type of surgery, n (%) | ||||
| Prosthesis7 | 69 (50) | 43 (48) | 26 (54) | 0.59 |
| Gamma nail | 66 (48) | 44 (49) | 22 (46) | 0.86 |
| Other8 | 3 (2.2) | 3 (3.3) | 0 (0) | 0.55 |
| Postoperative complications n (%) | ||||
| Postoperative delirium | 90 (65) | 60 (67) | 30 (63) | 0.71 |
| Fall | 12 (8.7) | 11 (12) | 1 (2.1) | 0.06 |
| Red blood cell transfusion | 49 (36) | 36 (40) | 13 (27) | 0.14 |
| Acute kidney failure | 25 (18) | 17 (19) | 8 (16) | 0.82 |
| Bladder retention | 45 (33) | 27 (30) | 18 (38) | 0.45 |
| Stool impaction | 108 (78) | 71 (79) | 37 (77) | 0.83 |
| Acute coronary syndrome | 5 (3.6) | 2 (2.2) | 3 (6.3) | 0.34 |
| Acute heart failure | 19 (14) | 11 (12) | 8 (17) | 0.60 |
| Atrial fibrillation | 14 (10) | 9 (10) | 5 (10) | 0.99 |
| Pulmonary embolism | 5 (3.6) | 3 (3.3) | 2 (4.2) | 0.99 |
| Stroke | 1 (0.7) | 1 (1.1) | 0 (0) | 0.99 |
| Infection | 44 (32) | 29 (32) | 15 (31) | 0.99 |
| Pressure ulcer | 12 (11) | 11 (12) | 1 (2.1) | 0.06 |
| Surgical revision | 1 (0.7) | 1 (1.1) | 0 (0) | 0.99 |
Abbreviations: CCI age-adjusted Charlson Comorbidity Index (score 0 to 37), COPD Chronic Obstructive Pulmonary Disease, ADL Activities of Daily Living (score 0 to 6), IADL Instrumental Activities of Daily Living (score 0 to 4), UPOG perioperative geriatric care unit
Data are mean (± SD), median (interquartile range), or number (%). Missing values are given only when they exist
Standard care: standard care group; BWST: bodyweight-supported treadmill rehabilitation group
1 Major cognitive impairment diagnosed before the fracture; 2 Cockcroft creatinine clearance < 60 ml/min; 3 Short form of IADL including four items (managing finance, managing medications, using telephone, managing transportation); 4 ≥ 2 falls in the previous year; 5 Delay from admission to the emergency department and surgery; 6 Delay between surgery and UPOG admission; 7 Unipolar prosthesis, bipolar prosthesis; 8 Dynamic Hip Screw, Percutaneous Screwing
Walking distances
On univariate analysis, patients in the BWST group achieved first sitting earlier than those in the standard care group (median 1 [1–1] vs. 1 [1–2] days; p = 0.03) and first walking earlier (median 1 [1–2] vs. 2 [1–3] days; p < 0.001). Walking distances at day 1 and day 6 were also significantly greater in the BWST group (both p < 0.001), as was the difference in walking distance between day 1 and day 6 (p < 0.001) (Table 2). On multivariate mixed model analysis, after controlling for baseline functional status, comorbidity burden, and delay between surgery and admission (all variables detailed in Supplementary Material 2), BWST rehabilitation remained significantly associated with greater daily walking distances over the first 6 days after admission to the UPOG (interaction between BWST and time: β = 3.31, 95% CI [2.47–4.16], p < 0.001) (Figs. 2 and 3, Supplementary Material 2).
Table 2.
Walking and functional characteristics of older patients by type of rehabilitation
| Total (n = 138) | Standard care (n = 90) | BWST (n = 48) | p-value | |
|---|---|---|---|---|
| Main outcome | ||||
| Difference in walking distance between day 1 and day 6 with walking aids1 (m), median (IQR) | 15 (5.0–29) | 10 (2.5–20) | 25 (10–48) | < 0.001 |
| Missing values | 5 (3.6) | 4 (4.4) | 1 (2.1) | |
| Postoperative walking characteristics | ||||
| Time to first sitting (days), median (IQR) | 1 (1–2) | 1 (1–2) | 1 (1–1) | 0.03 |
| Missing values | 3 (2.2) | 3 (3.3) | 0 (0) | |
| Time to first walking (days), median (IQR) | 2 (1–3) | 2 (1–3) | 1 (1–2) | < 0.001 |
| Missing values | 15 (10.9) | 10 (11.1) | 5 (10.4) | |
| Walking distance at day 1 with walking aids (m), median (IQR) | 0 (0–4.0) | 0 (0–1.0) | 2.0 (0–6.0) | < 0.001 |
| Walking distance at day 6 with walking aids (m), median (IQR) | 20 (5.0–30) | 10 (5.0–20) | 30 (10–50) | < 0.001 |
| Missing values | 5 (3.6) | 4 (4.4) | 1 (2.1) | |
| SPPB at day 6, median (IQR) | 0 (0–3) | 0 (0–4) | 1 (0–3) | 0.10 |
| Missing values | 26 (18.8) | 25 (27.8) | 1 (2.1) | |
| At discharge | ||||
| Morphine at discharge, n (%) | 70 (51) | 54 (60) | 16 (33) | 0.006 |
| Missing values | 5 (3.6) | 2 (2.2) | 3 (6.3) | |
| In-hospital mortality, n(%) | 5 (3.6) | 3 (3.3) | 2 (4.2) | 0.99 |
Length of hospital stay (days), mean ( ) |
12 ( 6.4) |
12 ( 6.7) |
12 (
|
0.66 |
| Admission to rehabilitation care, n (%) | 92 (67) | 62 (69) | 30 (63) | 0.46 |
| Return to home2, n (%) | 33 (23) | 20 (22) | 13 (27) | 0.54 |
| Other destination, n(%) | 7 (5.1) | 5 (5.6) | 2 (4.2) | 0.99 |
| Follow-up (30 days after surgery) | ||||
|
Re-admission at follow-up, n (%) |
4 (2.9) | 2 (2.2) | 2 (2.2) | 0.61 |
| Mortality 30 days after surgery, n (%) | 11 (8.0) | 7 (7.8) | 4 (8.3) | 0.99 |
Abbreviations: SPPB Short Physical Performance Battery (score 0 to 12)
Data are mean (± SD), median (interquartile range) or number (%). Missing values are given only when they exist
Standard care: standard care group; BWST: bodyweight-supported treadmill rehabilitation group
1 Walking aids adapted to the patient (antebrachial walker, 2-wheel walker, walking frame, crutches); 2 Institution was considered “home” for patients previously living in an institution
Fig. 2.
Mean walking distance (plotmean) in the perioperative geriatric care unit by type of rehabilitation. β = linear mixed model coefficient measuring interaction between time and walking distance. Solid line = mean walking distance of the standard care or BWST group. Thin line = walking distance progression for each patient. Standard care: standard care group; BWST: bodyweight-supported treadmill rehabilitation group. Abbreviations: UPOG: perioperative geriatric care unit
Fig. 3.
Daily walking distance (boxplot) in the perioperative geriatric care unit by type of rehabilitation. Data are median (horizontal line); box edges, interquartile range; and whiskers, range. Standard care: standard care group; BWST: bodyweight-supported treadmill rehabilitation group
Secondary outcome and safety
At discharge, morphine use was significantly less frequent in the BWST group compared with the standard care group (33% vs. 60%, p = 0.006) (Table 2). On univariate analysis of patients with dementia (median 18 [5.0–33] vs. 10 [1.0–19], p = 0.03) or those > 85 years old (median 21 [10–30] vs. 10 [2.0–20], p = 0.01), the BWST group showed greater improvement in the difference in walking distance with a walking aid between day 1 and day 6 after admission to the UPOG (Supplementary Material 3).
No significant differences were observed between groups regarding SPPB score, length of stay, discharge destination, or in-hospital and 30-day mortality (all p > 0.05) (Table 2).
No adverse effects or complications related to the BWST training were observed during the study period. Specifically, no falls, harness-related injuries, discomfort requiring discontinuation, or clinically significant increases in pain were reported during rehabilitation sessions.
Discussion
This study highlights the potential benefits of a connected BWST on walking recovery in acute postoperative management of HF in older patients hospitalized in a dedicated perioperative geriatric care pathway. We found a significant association between BWST training and earlier achievement of first sitting and first walking, along with an improvement in daily walking distance during the first 6 days after admission to the UPOG, without complications or adverse effects. Our subgroup analyses were exploratory and should be interpreted with caution, but they suggest that BWST-based rehabilitation may also benefit particularly frail populations, such as patients with dementia or very advanced age.
To our knowledge, only one previous case study (Bellelli et al. 2006) documented the introduction of BWST in acute postoperative care. This study focused on an 82-year-old woman with HF, dementia and poor rehabilitation engagement. Daily BWST training allowed for active participation and significantly improved walking ability and autonomy after 2 weeks, with benefits sustained after 6 months [30]. Although dementia negatively affects the rehabilitation process and functional outcomes, studies have demonstrated that enhanced rehabilitation strategies, particularly under the guidance of a geriatrician, may offer some benefits over conventional rehabilitation for people with dementia after HF surgery [31], which suggests that BWST training could enhance both walking and functional recovery in patients with dementia after HF.
Other studies focusing on treadmill training effectiveness in older adults with HF in an inpatient rehabilitation setting have shown mixed results. Van Ooijen et al.. compared treadmill rehabilitation in 70 older adults (mean age 83 years) with and without visual projections to usual rehabilitation over 6 weeks and showed a significant improvement in walking ability with treadmill rehabilitation [15]. Another study focused on patients with HF and sarcopenia (n = 38, mean age 79 years), where a 10-day rehabilitation program combining BWST training with conventional rehabilitation improved walking and balance abilities at 3 weeks, 3 months and 6 months as compared with conventional rehabilitation alone [32]. In a study by Ohoka et al., adding BWST training to standard physiotherapy over 12 weeks (n = 18, mean age 90 years) significantly improved daily walking distances and patient autonomy as compared with standard physiotherapy alone [33]. However, one study (n = 160, mean age 84 years) found no significant difference in walking or functional abilities comparing intensive rehabilitation, including BSWT training, and standard care over 16 weeks [34]. Methodological differences with our study, such as variations in settings (acute period vs. subacute period), rehabilitation intensity and duration, should be considered when interpreting these results.
An additional clinically relevant finding was the lower proportion of patients using morphine at discharge in the BWST group. Although standardized pain scores at admission and discharge were not available, opioid use may serve as a pragmatic proxy for clinically significant postoperative pain in this frail population. BWST training reduces mechanical constraints on the operated hip and may improve tolerance to early walking, thereby facilitating greater engagement in rehabilitation. Earlier mobilization, which was observed in the BWST group, has also been associated with improved pain control and reduced opioid requirements after orthopedic surgery [35]. These findings should be interpreted cautiously, but they suggest that BWST-based rehabilitation may contribute not only to functional recovery but also to improved pain management and reduced opioid exposure in older adults.
Several mechanisms may explain the observed associations. First, treadmill rehabilitation provides a task-specific repetitive approach facilitating the practice of gait cycles [15, 32]. Second, although full weight-bearing exercises are more effective to restore functional ability and balance than partial body-weight exercises [36], their tolerance is poor in acute postoperative management because of fracture, inflammatory syndrome and surgery, all resulting in considerable pain, well known to be the main cause of reduced participation in rehabilitation [35, 37]. BWST reduces mechanical constraints on the hip, potentially decreasing pain and thus improving patient adherence during rehabilitation [38]. Lastly, with such tools, walking speed and bodyweight relief can be adjusted for each patient, promoting the restoration of normal walking mechanics.
This study has several strengths. It was the first study evaluating the association between BSWT training and walking recovery abilities in a cohort of older adults with HF, particularly those in a dedicated orthogeriatric care pathway. Given the observational before–after design and the unequal sample sizes between groups, we focused on modeling associations rather than direct comparisons of group means. The use of a linear mixed-effects model allowed us to account for repeated measures within individuals and baseline heterogeneity, providing a more robust assessment of the relationship between BWST use and walking recovery over time. Additionally, our inclusion and exclusion criteria ensured that our sample was representative of most older adults with HF. Importantly, the observed associations are unlikely to be explained by temporal changes in usual care, as both cohorts were managed in the same unit, by the same multidisciplinary team, using identical care protocols, with the introduction of the BWST representing the only modification in routine practice.
There are several limitations to our study. The first limitation is the observational design, and we cannot exclude bias such as confounding, because some potential confounders were not accounted for, and measurement bias, because investigators were aware of the change in our routine practice. To limit overfitting and avoid overadjustment, we deliberately used a parsimonious multivariable model including only baseline clinically relevant confounders, which may have resulted in residual confounding but improves the robustness and interpretability of the estimates. Second, a significant number of patients (n = 124) were excluded because they did not meet the inclusion criteria, although their baseline characteristics were comparable to those of included patients. Third, the measurement of walking distance differed between groups (unit corridor vs. treadmill), except on day 1 and day 6 after admission to the UPOG. Treadmill walking and overground walking significantly differ in kinetic, kinematic and electromyographic parameters, which highlights the importance of considering these distinctions in the interpretation of our results [39]. Fourth, pain was not systematically assessed using standardized scales at admission or discharge, which limits the interpretation of differences in opioid use between groups. Lastly, this single-center study was conducted in a highly specialized environment that emphasizes early mobilization, and our results may not be extrapolated to conventional care [18].
Conclusion
This study explored the association between bodyweight-supported treadmill training and early postoperative walking recovery in a cohort of older adults with hip fracture in a dedicated perioperative geriatric care pathway. The results of this study suggest that this innovative rehabilitation approach using a connected bodyweight-supported treadmill was associated with a greater walking recovery as compared with standard care and was both feasible and safe for patients with hip fracture. Future interventional studies are needed to confirm these findings and determine the optimal rehabilitation protocol.
Supplementary Information
Acknowledgements
We wish to thank study participants and their families for contributing to the study.
Abbreviations
- HF
Hip Fracture
- BWST
Bodyweight-supported treadmill
- UPOG
Unit of perioperative geriatric care
- ED
Emergency department
- CCI
Age-adjusted Charlson comorbidity index
- ADL
Activities of daily living
- IADL
Instrumental activities of daily living
- SPPB
Short performance physical battery
- LOS
Length of stay
- SD
Standard deviation
- IQR
Interquartile range
- 95% CI
95% Confidence interval
- CEGIF
Ethics committee of Gérond’if
- AP-HP
Assistance Publique-Hôpitaux de Paris
- CNIL
Commission nationale de l’informatique et des libertés
Authors’ contributions
Study conception and design : Boddaert, Zerah, Cohen-Bittan, Genet, Nicolas. *Data collection* : Boddaert, Cohen-Bittan, Zerah. *Data analysis* : Genet. *Interpretation of data* : Genet, Zerah, Boddaert, Nicolas. *Preparation of the manuscript* : Nicolas. *Critical revision of the manuscript for important intellectual content* : All authors. The authors read and approved the final manuscript.
Funding
The body weight-supported treadmill used in this research was funded by Autonomia Grant (Ivry-Sur-Seine, France). Autonomia Grant had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The EzyGain company, manufacturer of the Ema treadmill, did not fund this research and had no role in study design, data collection, data analysis, data interpretation, or writing of the report.
Data availability
The datasets analyzed during the current study are available from author Pr Jacques Boddaert on reasonable request (jacques.boddaert@aphp.fr).
Declarations
Ethics approval and consent to participate
All methods were performed in accordance with the Declaration of Helsinki. This study received a favorable opinion from the Ethics Committee of Gérond’if (CEGIF) in Paris on December 2, 2024 (registration No. 122024). The database was declared to the French National Commission for Information Technology and Civil Liberties (CNIL) of Assistance Publique-Hôpitaux de Paris (AP-HP) for this study (No. 20190822165316). In accordance with French regulations for observational studies using routine care data, written informed consent was not required. However, all patients or their legal representatives were informed of the database and had the right to object to the use of their data for research purposes.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The datasets analyzed during the current study are available from author Pr Jacques Boddaert on reasonable request (jacques.boddaert@aphp.fr).