Separate logistics linked to more successful day-case hip and knee replacement rollout

Hospitals that physically and logistically separated their arthroplasty centers from general orthopedic departments were more successful at implementing a standardized day-case program for hip and knee replacement than units embedded within a broader department, according to a Danish cohort study published in Archives of Orthopaedic and Trauma Surgery.

Day-case hip and knee arthroplasty has become a major focus for health systems facing rising demand from patients with hip and knee osteoarthritis, because sending suitable patients home within hours of surgery reduces bed occupancy and improves cost-effectiveness. Yet achieving that goal depends on more than surgical technique or pain control. Previous studies have reported that logistics play a role in failed day-of-surgery discharge after hip and knee replacement, alongside postoperative medical or physiological issues. The setup of arthroplasty centers differs widely, with some units functioning as largely independent facilities and others embedded in orthopedic departments with shared resources, and hospital resources such as operative capacity, beds and staffing can be affected by high uptake of acute patients if resources are not exclusively allocated to the arthroplasty center.

The new study, part of the Center for Fast-track Hip and Knee Replacement collaboration, was designed to test whether center type influenced how well a common day-case pathway actually worked in practice. In September 2022, all seven participating centers began clinical implementation of a day-case surgery setup with identical eligibility and discharge criteria. The researchers categorized the centers into three types. Satellite arthroplasty centers, of which there were two, performed only primary hip and knee arthroplasties and had a separate logistical setup, referring complex primary cases and revisions to a highly specialized arthroplasty unit at another site. Elective arthroplasty centers, of which there were three, performed complex primary and revision arthroplasties but also had a separate logistical setup. Arthroplasty units at orthopedic departments, of which there were two, performed all primary and revision procedures but were logistically integrated into an orthopedic department with a trauma department. All were hospital centers rather than ambulatory surgical centers.

Under the shared protocol, patients aged 18 to 80 undergoing unilateral primary total hip, total knee or unicompartmental knee arthroplasty were eligible for day-case surgery in the absence of major heart disease, need for home oxygen, insulin-dependent diabetes mellitus, body mass index below 18.5 or above 40, glomerular filtration rate below 60 mL/min/1.73 m2, mechanically treated sleep apnea, clinical frailty or recent falls. The fast-track protocol included high-dose glucocorticoids preoperatively, tranexamic acid given intraoperatively, and general or spinal anesthesia with short-acting agents to facilitate early mobilization. Local infiltration anesthesia with at least 150 mL of ropivacaine was administered in knee arthroplasties. Multimodal analgesia relied on paracetamol, NSAIDs or COX-2 inhibitors, and minimal opioid use, while antibiotic prophylaxis and a single postoperative dose of rivaroxaban or apixaban for thromboprophylaxis completed the regimen. Mobilization began within three hours of surgery with full weight-bearing ambulation.

Discharge criteria were equally explicit. Patients needed stable vital signs with an Early Warning Score below 2, adequate pain control with a Numerical Rating Scale below 3 at rest and below 5 when walking, minimal nausea, no excessive postoperative bleeding, steady gait with crutches and the ability to use stairs if required at home. Successful day-of-surgery discharge was defined as the patient being discharged on the same date as the surgery. The research team prospectively recorded length of admission and reasons for unsuccessful discharge, categorizing failures as medical if any medical reasons were noted and as logistical if only logistical reasons applied. Logistical reasons included insufficient mobilization or awaiting physiotherapy, late return to the bed ward from surgery, inability to discharge before 9 PM, patient discomfort with discharge, or awaiting postoperative x-rays. Medical reasons covered pain, nausea and vomiting, affected vital signs, urinary retention, residual spinal anesthesia, wound oozing and surgical complications.

The results showed a clear rise in day-of-surgery discharge after implementation across all center types, but a pronounced difference in the level achieved. During a baseline period from July 2019 to December 2019, before the standardized setup and before the COVID-19 pandemic, 3,974 patients were operated at the centers, and day-of-surgery discharge rates stood at 3.9 percent in satellite centers, 5.5 percent in elective centers and 7.4 percent in the integrated units. In the first year after implementation, covering all 6,718 study patients of whom 1,357 were operated at satellite centers, 4,309 at elective centers and 1,052 at integrated units, the overall discharge rates reached 30 percent, 23 percent and 14 percent respectively. Notably, the integrated units had started from the highest baseline, yet ended up with the lowest uptake.

The contrast was even sharper when analysis was restricted to patients actually eligible for day-case surgery. Compared with the integrated arthroplasty units, where 36 percent of eligible patients achieved successful day-of-surgery discharge, eligible patients were more likely to be discharged on the day of surgery at satellite centers, where the rate was 54 percent, with an adjusted odds ratio of 3.0 and an adjusted risk difference of 25 percentage points, and at elective centers, where the rate was 60 percent, with an adjusted odds ratio of 3.8 and an adjusted risk difference of 31 percentage points. These mixed-effects models used the individual centers as a random effect and were adjusted for sex, age, body mass index, arthroplasty type, living situation and use of a walking aid. Patients at the satellite and elective centers were also more likely to be eligible for day-case surgery in the first place.

When discharge failed, the reasons differed systematically by center type. Among day-case eligible patients with failed day-of-surgery discharge attributed to logistical issues only, such failures were more pronounced in the integrated units, accounting for 33 percent of failed discharges, compared with 21 percent at satellite centers and 13 percent at elective centers. The most common logistical reason was late return to the bed ward in satellite centers, cited in 79 percent of their logistical failures, while insufficient mobilization dominated in the integrated units and elective centers. Failed discharges attributed to medical issues in any way were similarly distributed across center types, at roughly 24 to 28 percent, suggesting that the gap between center types was driven mainly by operational rather than clinical factors.

The authors argue that the difference may reflect how exclusively resources are reserved for arthroplasty patients. Satellite and elective centers, despite being hospital centers with inpatient bed-wards, might have more exclusive resources available for day-case surgery, similar in some respects to ambulatory centers, whereas at an integrated unit those resources can be more vulnerable to competing demands from a department with a volatile and acute trauma workload. The team also notes that patients treated with unicompartmental knee arthroplasty are generally reported to be more easily discharged on the day of surgery, but in this study the overall use of arthroplasty types was similar between center types, and integrated units actually had the highest use of unicompartmental knee replacement alongside the lowest day-of-surgery discharge rate. One elective center performed primary unicompartmental knee procedures in eligible ASA 1 to 2 patients in an ambulatory operating theatre without a bed-ward, which likely contributed to the elective centers’ higher success rate.

The researchers caution that several limitations temper the findings. Day-case eligibility in the baseline period was based on unknown local criteria, and the contribution of the ambulatory operating theatre at one elective center could not be assessed at the individual-patient level. Unmeasured factors such as management involvement, staffing and cultural norms could influence how well a day-case setup performs. Because all centers were hospital arthroplasty units with inpatient bed-wards, the results do not represent day-case setups in ambulatory surgical centers, where published success rates of 90 to 100 percent have been reported among highly selected patients. The centers do, however, perform approximately 40 percent of annual arthroplasty procedures in Denmark within a public healthcare setup with identical economic incentives, and prior publications from the same cohort have found the day-case setup safe regarding readmissions, complications and primary care contacts. The authors conclude that decision-makers should consider the importance of separate logistics and predictable resources when deciding where and how to implement day-case hip and knee arthroplasty.

Subject of Research: Association between arthroplasty center logistical setup and success of a standardized day-case hip and knee replacement program in Denmark

Article Title: Arthroplasty centers logistically separated from general orthopedic departments were associated with a more successful implementation of a standardized day-case setup

Article References: Jensen, C. B., Danielsen, O., Varnum, C., Jakobsen, T., Andersen, M. R., Bieder, M. J., Overgaard, S., Jørgensen, C. C., Kehlet, H., & Gromov, K. (2026). Arthroplasty centers logistically separated from general orthopedic departments were associated with a more successful implementation of a standardized day-case setup. Archives of Orthopaedic and Trauma Surgery, 146(1), Article 386. https://doi.org/10.1007/s00402-026-06525-8

Image Credits: AI Generated

DOI: 10.1007/s00402-026-06525-8

Keywords: hip arthroplasty, knee arthroplasty, day-case surgery, day-of-surgery discharge, fast-track pathway, arthroplasty centers, Denmark, orthopedic surgery, logistics, implementation study, total hip replacement, total knee replacement