Ethical approval
All procedures involving human participants were conducted in accordance with the ethical standards of the institutional research committee and adhered to the Declaration of Helsinki. Ethical approval was obtained from the institutional review board of the 960th Hospital of the PLA Joint Logistic Support Force (Approval ID: 2023–110). Written informed consent was obtained from all participants or from legally authorized representatives prior to inclusion.
Study design
This study was conducted at a tertiary academic orthopedic trauma center capable of managing complex geriatric fractures. During the period from May 2023 to May 2024, all older adults presenting with suspected intertrochanteric femoral fractures were systematically evaluated through a unified workflow. Eligible patients were enrolled consecutively and managed according to one of two perioperative care pathways: the established conventional clinical pathway or the ERAS pathway, newly implemented in the department during this period. Both pathways used identical operative techniques and internal fixation methods, enabling a valid comparison of perioperative processes. Data collection was standardized and performed prospectively within the patient’s electronic medical record during clinical care; no retrospective chart reconstruction occurred. All surgical procedures in both pathways were performed by a fixed team of three senior orthopedic trauma surgeons, each with more than 200 independent intramedullary fixation procedures for intertrochanteric femoral fractures completed prior to the study period. No new surgeons, fellows, or trainees acted as primary operators during the study. The same operative team structure was maintained throughout May 2023 to May 2024, ensuring technical homogeneity and eliminating variability introduced by surgeon experience or personnel changes. Standardized operative indications, reduction principles, and fixation techniques were uniformly applied across all cases.
Clarification of group assignment and minimization of selection bias
Because this was not a randomized trial, group assignment was clarified as a predefined time–based departmental workflow allocation. Patients were not individually assigned to the conventional or ERAS pathway according to surgeon preference, patient preference, family preference, bed availability, or baseline clinical condition. Instead, the care pathway was determined by whether the patient was admitted before or after formal departmental activation of the ERAS pathway. This design minimized discretionary selection by clinicians but could not completely eliminate potential secular effects related to time. To reduce this risk, the study was conducted within a single institution over a limited 1–year period, with the same senior operative team, identical fixation strategy, unified perioperative staffing, consistent postoperative monitoring, and standardized prospective data collection. Baseline characteristics were compared between groups, and multivariable regression analyses were performed to further account for measured confounding. Because workflow–based allocation was not random, residual confounding could not be completely excluded. In particular, admission timing, weekday versus weekend admission, time from injury to admission, fracture severity, perioperative staffing conditions, and temporal changes in departmental practice may have influenced early recovery outcomes. These factors were therefore considered during bias assessment. Where available, time from injury to admission, fracture severity, age, sex, American Society of Anesthesiologists class, Charlson Comorbidity Index, baseline hemoglobin, and pre–injury mobility were included in adjusted analyses. However, unmeasured temporal and workflow–related confounders may remain and were acknowledged as limitations of the study.
Patient screening, enrollment, and eligibility
Upon arrival, all patients underwent immediate triage and clinical evaluation by orthopedic attending physicians. Screening involved clinical history, physical examination, standard radiography, and laboratory assessment. Eligible patients were aged 70 years or older at admission, had an intertrochanteric femoral fracture confirmed by standard anteroposterior and lateral hip radiographs, and underwent additional computed tomography when clarification of fracture morphology or lateral wall integrity was required. Eligibility also required suitability for operative treatment using a standardized intramedullary fixation approach, sufficient cognitive capacity to understand perioperative instructions and participate in rehabilitation, completion of eligibility confirmation before enrollment, and admission and management entirely within the defined study period. Patients were excluded in the presence of additional fractures involving major anatomical locations, including the pelvis, vertebrae, or contralateral hip, or severe polytrauma; pathological fractures secondary to tumors, metastasis, metabolic bone disease, or other nontraumatic causes; severe organ dysfunction, including decompensated heart failure classified as New York Heart Association class III–IV, advanced hepatic insufficiency, end-stage renal disease requiring dialysis, or severe chronic obstructive pulmonary disease requiring home oxygen; uncontrolled coagulopathy, hematologic disorders, systemic inflammatory disease, or severe immunosuppression; active psychiatric or neurocognitive disorders preventing reliable cooperation with perioperative care; refusal of operative management; or incomplete clinical records for key perioperative variables. A dual–pathway clinical management model was used during the study period. Patients were managed either under the conventional care pathway (pre–existing standard practice) or the newly implemented ERAS pathway.
Conventional care pathway
The conventional pathway reflected long–established local practice for managing intertrochanteric fractures and was characterized by non–standardized processes across the preoperative, intraoperative, and postoperative phases. In the preoperative phase, patients were admitted through routine triage and underwent laboratory testing, coagulation profiling, chest radiography, electrocardiography, and anesthesiology evaluation without predefined time targets. Fasting from solids and liquids began at midnight before surgery, and preoperative optimization was performed at the discretion of the treating clinician due to the absence of standardized readiness criteria. Pain control relied mainly on intermittent intravenous or intramuscular analgesics administered only when patients verbally reported moderate or severe pain. During the intraoperative phase, the anesthesiologist selected either regional or general anesthesia according to clinical judgment. Fluid management was based on conventional hemodynamic monitoring without the use of goal–directed strategies. Standard intramedullary fixation was performed, and temperature control measures were applied inconsistently. In the postoperative phase, oral intake was delayed until bowel motility returned, typically 24–48 h after surgery, and mobilization was postponed until pain became tolerable and the wound was deemed stable. Rehabilitation lacked structured progression criteria, and catheter or drainage removal followed routine local practice without standardized timelines. Complication monitoring was reactive rather than protocol–driven.
ERAS clinical pathway
The core elements of the ERAS pathway were adapted from published ERAS recommendations for orthopedic surgery and evidence–based hip–fracture care guidelines, including preoperative education, abbreviated fasting, multimodal opioid–sparing analgesia, goal–directed fluid management, early oral intake, thromboprophylaxis, device minimization, and early mobilization21,22.
ERAS preoperative phase
In the ERAS pathway, patients underwent a streamlined and accelerated preoperative process beginning with a “green–channel” diagnostic workflow, in which radiographs, CT when indicated, full blood panels, coagulation tests, chest imaging, and electrocardiography were completed within 4 h of hospital arrival. Within the first 24 h, an interdisciplinary team comprising orthopedic surgeons, anesthesiologists, and internal medicine specialists reviewed comorbidities and finalized an individualized surgical plan. A dedicated ERAS nurse subsequently provided a structured 30–45 min education session within 24–72 h, addressing fracture characteristics, surgical goals, the importance of early mobilization, anticipated pain, and the multimodal analgesia strategy, breathing and limb–activation exercises, postoperative expectations, and psychological reassurance, supported by illustrated diagrams and simplified exercise guides, with family members participating and confirming completion of training. Preoperative physiological optimization was conducted by an internal medicine consultant who systematically evaluated and stabilized cardiovascular, respiratory, renal, and metabolic function, including blood pressure, glucose, and electrolyte control, smoking cessation counseling, incentive–spirometry–based pulmonary conditioning, anemia correction for hemoglobin <110 g/L, venous thromboembolism risk assessment, and nutritional screening to identify frailty. Nutritional preparation followed ERAS principles: normal meals were allowed until 6–12 h before surgery, clear fluids until 2 h before anesthesia, and prolonged fasting was avoided except when medically necessary; frail patients received high–protein oral supplements to reduce catabolic stress and postoperative insulin resistance21,22.
ERAS intraoperative phase
During the intraoperative phase of the ERAS pathway, anesthesia was delivered according to standardized, goal–directed principles that prioritized regional anesthesia to reduce postoperative delirium risk, with carefully titrated sedation to prevent oversedation and active warming to maintain normothermia between 36–37 °C. Regional nerve blocks were incorporated whenever appropriate to support opioid–sparing analgesia. Fluid management followed a goal–directed strategy using dynamic hemodynamic monitoring, including stroke volume variation, mean arterial pressure, and urine output targets (≥ 0.5 mL/kg/h), ensuring avoidance of over–resuscitation and the consistent use of balanced crystalloid solutions21,23. Surgical management relied on a minimally invasive, standardized intramedullary fixation technique characterized by small skin incisions, blunt soft–tissue dissection, fluoroscopy–guided fracture reduction, and precise nail insertion to protect the lateral femoral wall. Hemostasis was systematically secured before closure, and wound drains were avoided whenever feasible. Operative time and intraoperative blood loss were documented in real time to ensure procedural consistency and quality control.
ERAS postoperative phase
Postoperatively, multimodal analgesia formed the foundation of pain control. Unless contraindicated, patients received scheduled non–opioid baseline analgesia with acetaminophen 500 mg every 6–8 h and a cyclooxygenase–2 inhibitor according to renal function, gastrointestinal risk, and cardiovascular risk. Regional analgesia, including ultrasound–guided fascia iliaca compartment block or femoral nerve block with ropivacaine, was used when coagulation status and clinical condition allowed. Rescue opioid analgesia was administered only when the numeric rating scale (NRS) score remained ≥4 despite baseline therapy, using short–acting opioids titrated to clinical response. Excessive sedation and long–acting opioids were avoided to reduce delirium, respiratory depression, constipation, and fall risk. Pain assessments were performed at 12, 24, and 48 h, and opioid exposure was converted to morphine–equivalent dose for analysis. Mobilization began within hours of anesthesia recovery following a structured progression: on postoperative day 0, patients performed ankle pumps, quadriceps contractions, gluteal isometrics, and sat at the bedside; on day 1, patients stood with assistance and initiated walker–assisted ambulation; by days 2–3, patients advanced to longer walking distances and stair training when appropriate, with weight–bearing individualized according to fracture stability and physiotherapists documenting functional milestones daily. Early oral nutrition was introduced within 6 h after surgery, starting with clear liquids and advancing to soft and regular diets as tolerated, allowing for tapering of intravenous fluids once adequate oral intake was established. Pulmonary optimization included incentive spirometry every 2 h, assisted coughing, and upright positioning for at least 2 h per day. Thromboprophylaxis followed ERAS best practices, with pharmacologic agents initiated within 12 h unless contraindicated, continuous use of mechanical compression devices until independent ambulation, and daily limb assessments. Device management emphasized early removal, with urinary catheters withdrawn within 24–48 h and surgical drains avoided whenever possible. Discharge readiness was confirmed when patients exhibited stable vital signs, adequate oral intake, controlled pain managed with oral medications, independent ambulation using assistive devices, a clean and dry surgical wound, and completion of discharge education for both the patient and family21,22,24.
To ensure reproducibility and strict adherence to ERAS principles, the pathway incorporated a standardized set of mandatory elements. An accelerated diagnostic workflow, referred to as the “green–channel”, was used to complete essential imaging and laboratory examinations within 4 h of admission, followed by interdisciplinary evaluation by the orthopedic, anesthesiology, and internal medicine teams within 24 h. A certified ERAS nurse delivered a structured 30–45-minute education session that included psychological counseling and mobility training. Comprehensive preoperative optimization included anemia correction, pulmonary conditioning, glycemic regulation, electrolyte stabilization, and frailty and nutritional screening. An abbreviated fasting regimen permitted clear fluids until 2 h before anesthesia induction. Regional anesthesia was prioritized and supplemented by nerve blocks to minimize opioid exposure, while goal–directed fluid management based on dynamic hemodynamic indices was used to maintain euvolemia. A standardized minimally invasive intramedullary fixation technique was applied, with particular attention to fracture reduction quality and preservation of the lateral femoral wall. The multimodal analgesia protocol incorporated scheduled pain assessments at 12, 24, and 48 h postoperatively. Early oral nutrition was initiated within 6 h after recovery from anesthesia, and structured mobilization began with bedside sitting on postoperative day 0. Early device removal included urinary catheter withdrawal within 24–48 h whenever feasible. Physiotherapy milestones were documented daily using standardized rehabilitation progress forms. Uniform application of these elements ensured delivery of an identical, protocolized intervention to all patients in the ERAS group.
Outcome measures
Outcome measures were evaluated systematically throughout hospitalization using predefined, standardized criteria to ensure reproducibility and minimize interobserver variability11,25,26. All assessments were contemporaneously documented in the electronic medical record by trained clinical staff. The evaluated domains encompassed perioperative efficiency, postoperative physiological recovery, pain trajectories, hematologic stability, functional mobility, and surveillance for postoperative complications. Perioperative efficiency was assessed using three core indicators. The time from hospital admission to the initiation of anesthesia was automatically recorded in the hospital information system and used to reflect the efficiency of the diagnostic and preoperative optimization process. Operative duration was defined as the interval between skin incision and wound closure and was documented electronically in the operating room. Intraoperative blood loss was estimated by combining suction canister volume, after subtraction of irrigation fluid, with gravimetric assessment of surgical sponges using calibrated digital scales. Final values were recorded as the average of measurements independently reported by both the scrub nurse and the circulating nurse. Postoperative physiological recovery was monitored through serial hemoglobin measurements obtained within 6 h preoperatively and repeated 24–36 h after surgery using standardized automated hematology analyzers, allowing calculation of absolute hemoglobin decline as a marker of hemodynamic stability and perioperative blood conservation. Pain intensity was assessed using the 0–10 Numerical Rating Scale at fixed time points of 12, 24, and 48 h after recovery from anesthesia. Assessments were performed by trained nursing staff, and annual competency evaluations were conducted to ensure consistency. Length of postoperative hospital stay was defined as the number of days from surgery to discharge, with discharge determined by a multidisciplinary panel in accordance with standardized milestones for mobility, pain control, wound stability, and readiness for rehabilitation. Functional mobility outcomes were tracked using a structured physiotherapy log, recording time to first sitting, first assisted standing, and first ambulation with a walker, as well as measured ambulation distances during postoperative days 1–3 using a calibrated ward walkway to ensure precise and objective quantification. At discharge, patients were categorized into standardized levels of ambulation based on physiotherapist evaluation. These categories included independent ambulation with a walker, supervised ambulation, and assisted ambulation requiring full support. This classification enabled consistent comparison of functional outcomes across patients. Postoperative complications were monitored continuously in accordance with an institution–wide adverse event protocol. Cardiopulmonary events were defined as pneumonia, atelectasis, acute heart failure, arrhythmia, or pulmonary embolism. All diagnoses were made according to established guideline–based criteria and were confirmed by cardiology or pulmonology specialists. Venous thromboembolism was assessed using duplex ultrasonography performed upon clinical suspicion or in high–risk individuals. Delirium was screened daily using the confusion assessment method by trained nursing staff, with documentation of cognitive fluctuations and behavioral abnormalities. Wound complications, including infection, hematoma, and delayed healing, were evaluated daily by the orthopedic team, with additional imaging or laboratory testing obtained when indicated. Urinary retention was defined as failure to void after catheter removal requiring reinsertion, whereas gastrointestinal disturbances such as constipation or ileus were diagnosed based on absent bowel movements, intolerance to oral intake, or radiographic findings. All complications were graded using the Clavien–Dindo classification to ensure standardized severity reporting across the cohort. All outcomes in the present study were assessed during the index hospitalization. No systematic post–discharge follow–up was performed for medium–term complications, readmission, institutionalization, functional recovery, quality of life, or mortality after discharge. Therefore, the outcome assessment was limited to early in–hospital perioperative recovery.
Blinding and bias reduction in outcome assessment
Because of the nature of the perioperative care intervention, patients, surgeons, anesthesiologists, nurses, and physiotherapists could not be blinded to pathway allocation. This limitation was particularly relevant for subjective outcomes such as pain scores and functional mobility assessment. To reduce observer bias, pain was assessed using the standardized 0–10 Numerical Rating Scale at fixed postoperative time points by trained nursing staff, and functional milestones were recorded using predefined operational criteria rather than subjective global judgment. First sitting, first assisted standing, first walker–assisted ambulation, and ambulation distance were documented in structured physiotherapy logs, and walking distance was measured using a calibrated ward walkway. Objective outcomes, including admission–to–anesthesia time, operative duration, hemoglobin values, opioid consumption, length of stay, and mortality, were extracted from electronic medical records. Complications were defined using prespecified clinical criteria and verified through source–document review. Nevertheless, the lack of blinding may have introduced observer bias, and this was considered when interpreting subjective recovery outcomes.
Quality control and interobserver reliability
A multidimensional quality–control framework was implemented to ensure methodological rigor, procedural consistency, and reproducibility. All orthopedic surgeons performing intramedullary fixation had each completed more than 200 prior procedures, ensuring uniform technical proficiency across cases. ERAS nursing staff received structured training that encompassed psychological counseling, delivery of standardized patient education, and postoperative monitoring requirements. Physiotherapists adhered to unified rehabilitation protocols and documented patient progress using standardized daily assessment forms; protocol adherence was reviewed weekly by the rehabilitation supervisor. Data collection reliability was maintained through dual extraction of all variables by two independent researchers, with discrepancies resolved by re-examining original source documents; interobserver agreement for categorical outcomes exceeded 95%. To further ensure fidelity to the ERAS pathway, pathway adherence was assessed using the 13 predefined mandatory ERAS elements. Each element was recorded as completed, not completed, or not applicable because of a documented clinical contraindication. For each patient, the overall adherence rate was calculated as the number of completed applicable ERAS elements divided by the total number of applicable elements. High adherence was defined as completion of ≥90% of applicable elements, moderate adherence as 80–89%, and major protocol deviation as completion of <80% of applicable elements or omission of a safety–critical component without documented justification. Safety–critical components included perioperative risk assessment, venous thromboembolism prophylaxis, scheduled pain assessment, early mobilization assessment, and postoperative monitoring for complications. A monthly audit was conducted by a joint orthopedic–anesthesiology oversight committee to review adherence rates, identify deviations, document reasons for non–compliance, and provide feedback to clinical staff.
Statistical analysis
A priori sample size estimation was performed based on the primary perioperative outcome of postoperative length of stay. Historical institutional data suggested that ERAS implementation was associated with a reduction in postoperative hospitalization of approximately 1.5 days, with an estimated standard deviation of 2.0 days. Using a two–sided independent–samples t–test with an α level of 0.05 and statistical power (1 − β) of 0.80, the minimum required sample size was calculated to be 34 participants per group. The final cohort of 80 patients (40 per pathway) exceeded this requirement, providing adequate power to detect clinically meaningful differences across all primary and secondary outcomes27.
Statistical analyses were conducted according to a prespecified analytical plan to compare all outcome domains between the ERAS and conventional care groups. All analyses were performed using validated statistical software. Data preprocessing included evaluation of distributional normality for all continuous variables using the Shapiro–Wilk test, along with outlier screening through boxplot inspection to identify potential entry errors or exceptional clinical scenarios. Missing data were infrequent owing to real–time electronic documentation; when present, complete–case analysis was applied to avoid the introduction of bias through imputation. Continuous variables were summarized as mean ± standard deviation when normally distributed, and between–group differences were examined using independent–samples t–tests. For variables deviating from normality, nonparametric Mann–Whitney U testing was used. Categorical variables were presented as frequencies and percentages, with between–group comparisons conducted using chi–square tests or Fisher’s exact test when expected cell counts were small. All tests were two–tailed, and a p value < 0.05 was interpreted as statistically significant. The outcome hierarchy was prespecified. Postoperative length of stay was the primary outcome. Secondary outcomes included admission–to–anesthesia time, intraoperative blood loss, postoperative hemoglobin decline, pain scores, opioid consumption, mobilization milestones, ambulation distance, postoperative complications, and ERAS adherence. Because multiple secondary outcomes were evaluated in this implementation–focused study, no formal multiplicity adjustment was applied to secondary endpoints. Therefore, secondary outcome findings were interpreted as exploratory and supportive, with emphasis placed on effect sizes, direction of estimates, and consistency across related recovery domains rather than isolated p values. Confidence intervals (CIs) were calculated at the 95% level where applicable to provide estimates of effect precision. To reduce overfitting in this modest cohort, adjusted analyses were restricted to the primary outcome and selected continuous secondary outcomes and were interpreted as exploratory sensitivity analyses. Adjusted linear regression models used a parsimonious covariate set selected a priori, including age, American Society of Anesthesiologists class, baseline hemoglobin, and fracture severity. Because the number of in–hospital complication events was limited, no full multivariable logistic regression model was fitted for overall complications.