General Anaesthesia vs Spinal Anaesthesia: Patient Outcomes and Success in Outpatient Primary Total Knee and Hip Arthroplasty (GASPS)

January 2, 2026 updated by: Region Örebro County

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common operations used to treat severe joint disease, most often caused by osteoarthritis. An increasing number of these procedures are now performed as outpatient surgery, meaning that patients can go home on the same day as the operation. This can be beneficial for both patients and healthcare systems, but it requires safe and efficient anaesthetic care.

Two different types of anaesthesia are commonly used for these operations: general anaesthesia (where the patient is asleep) and spinal anaesthesia (where the lower part of the body is numbed). Both methods are well established and widely used. Previous studies suggest that the choice of anaesthesia may affect how quickly patients recover, how comfortable they feel after surgery, and whether they can be safely discharged on the day of surgery. However, most existing studies are based on retrospective data, and there is limited randomized evidence comparing these anaesthetic techniques in the outpatient setting.

The GASPS trial is a multicentre, randomized, phase IV clinical study that compares general anaesthesia and spinal anaesthesia in adults undergoing outpatient primary total knee or hip arthroplasty. A total of 600 participants will be included and randomly assigned to receive one of the two anaesthetic methods on the day of surgery. All participants will receive standard surgical and perioperative care, and both anaesthetic techniques are part of routine clinical practice.

The main aim of the study is to investigate whether the type of anaesthesia influences the chance of successful same-day discharge, defined as going home on the day of surgery without needing to be readmitted within 48 hours. The study will also examine recovery time, pain, nausea and vomiting, use of pain medication, complications, patient-reported recovery and function, and healthcare costs. In addition, patient experiences of anaesthesia and postoperative recovery will be explored through interviews in a smaller group of participants.

Participants will be followed using questionnaires and medical records from the day of surgery up to 12 months after the operation. The results of this study are expected to provide clear and reliable information to help guide anaesthetic care for patients undergoing outpatient hip and knee replacement surgery.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are among the most frequently performed elective surgical procedures and are highly effective treatments for advanced joint disease, most commonly osteoarthritis. Over the past decade, improvements in surgical techniques, perioperative care pathways, anaesthetic management, and postoperative rehabilitation have enabled an increasing proportion of these procedures to be performed as outpatient surgery, allowing patients to return home on the day of surgery. Outpatient arthroplasty has the potential to improve patient satisfaction, reduce hospital length of stay, lower healthcare costs, and decrease the risk of hospital-acquired complications. However, achieving safe and successful same-day discharge requires carefully optimized perioperative care.

Anaesthetic management is a central component of outpatient arthroplasty pathways. Both general anaesthesia (GA) and spinal anaesthesia (SA) are routinely used for TKA and THA, and both techniques are well established with extensive safety data. Neuraxial anaesthesia has traditionally been associated with reduced intraoperative blood loss and certain postoperative complications, and it is commonly recommended in clinical guidelines for hip and knee arthroplasty. In contrast, modern general anaesthesia using short-acting intravenous agents may offer advantages in the outpatient setting, including predictable onset and offset, rapid recovery of motor function, and reduced postoperative nausea and vomiting when volatile agents are avoided.

Despite widespread clinical use of both techniques, the optimal choice of anaesthesia for outpatient TKA and THA remains uncertain. Much of the existing evidence comparing GA and SA is derived from retrospective observational studies and registry-based analyses. These studies often include mixed inpatient and outpatient populations and are subject to confounding by indication, as patients receiving GA frequently differ from those receiving SA with respect to comorbidity, functional status, or anticipated surgical complexity. As a result, it is difficult to determine whether observed differences in outcomes are attributable to the anaesthetic technique itself or to underlying patient characteristics. Randomized clinical trials specifically designed to compare GA and SA in the outpatient arthroplasty setting are scarce.

The GASPS (General Anaesthesia vs Spinal Anaesthesia: Patient Outcomes and Success in Outpatient Primary Total Knee and Hip Arthroplasty) trial was designed to address this evidence gap. GASPS is a multicentre, randomized, phase IV clinical trial comparing GA and SA in adults undergoing outpatient primary TKA or THA. The overarching aim of the trial is to generate high-quality randomized evidence on whether the choice of anaesthetic technique influences the likelihood of successful same-day discharge and postoperative recovery in outpatient arthroplasty.

A total of 600 participants will be enrolled across multiple orthopaedic centres in Sweden. Eligible patients scheduled for outpatient primary TKA or THA are randomized on the day of surgery to receive either GA or SA. Randomization is performed using a stratified permuted block design, with stratification by type of surgery (knee or hip arthroplasty) and study site, to ensure balanced allocation across groups. Allocation concealment is maintained until shortly before surgery. Due to the nature of the interventions, blinding of patients and clinical staff is not feasible; however, data analysts remain blinded during analysis.

Both anaesthetic techniques are delivered according to standardized protocols that reflect contemporary routine clinical practice. General anaesthesia is provided using total intravenous anaesthesia with short-acting agents, primarily propofol and remifentanil, administered by trained anaesthesiologists. Spinal anaesthesia is administered as a single-shot intrathecal block with bupivacaine, with optional intrathecal opioid adjuncts and light sedation as clinically indicated. No experimental drugs or procedures are introduced, and all perioperative care apart from the assigned anaesthetic technique follows local standard practice.

The primary outcome of the trial is successful same-day discharge, defined as discharge from hospital on the day of surgery without readmission within 48 hours. This outcome was chosen as a clinically meaningful and patient-relevant measure of perioperative success in outpatient arthroplasty, integrating both recovery efficiency and short-term safety. Successful same-day discharge reflects the combined effects of anaesthetic technique, surgical care, postoperative recovery, and early complication rates.

Secondary outcomes are designed to capture multiple dimensions of perioperative and postoperative recovery. These include perioperative time metrics related to anaesthesia induction, surgery, and recovery; early postoperative outcomes such as pain, nausea and vomiting, opioid consumption, mobilisation, and adverse events; and patient-reported outcomes assessing quality of recovery, function, and health-related quality of life. Recovery is conceptualized as a multi-phase process, ranging from early recovery in the postoperative care unit to longer-term recovery at home. Validated instruments such as the Quality of Recovery-15 (QoR-15), Knee injury and Osteoarthritis Outcome Score (KOOS), Hip disability and Osteoarthritis Outcome Score (HOOS), and EQ-5D-5L are used to assess these domains over time.

In addition to quantitative outcomes, the GASPS trial incorporates a qualitative component to explore patient experiences of anaesthesia and postoperative recovery. Semi-structured interviews are conducted with a subset of participants several weeks after surgery. This mixed-methods approach allows for a deeper understanding of patient perceptions, expectations, and experiences that may not be fully captured by standardized questionnaires, and provides important contextual information to complement clinical and patient-reported outcome data.

Participants are followed from the day of surgery up to 12 months postoperatively using a combination of medical record review and patient-completed questionnaires. Safety monitoring focuses on adverse events occurring in the immediate perioperative period, while longer-term follow-up captures functional outcomes, quality of life, healthcare utilization, and productivity losses. A health economic evaluation is embedded within the trial to compare GA and SA in terms of costs and quality-adjusted life years, with the aim of informing resource-efficient anaesthetic strategies for outpatient arthroplasty.

By integrating randomized clinical data, patient-reported outcomes, qualitative insights, and health economic analyses, the GASPS trial aims to provide a evaluation of the role of anaesthetic technique in outpatient total knee and hip arthroplasty.

Study Type

Interventional

Enrollment (Estimated)

600

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. The participant has given their written consent to participate in the trial.
  2. Planned for primary TKA or THA.
  3. Adults aged 18 to 80 years at time of written consent.
  4. ASA (American Society of Anaesthesiologists) classification 1 or 2, or 3 without significant functional impairment.
  5. Scheduled start of surgery before 13:00.
  6. Ability to communicate in Swedish, ensuring understanding of informed consent and follow-up procedures.

Exclusion Criteria:

  1. Indication for surgery other than degenerative or inflammatory joint diseases (e.g. fracture).
  2. Body mass index (BMI) > 35 kg/m.
  3. Preoperative opioid use exceeding 20 mg oral morphine equivalents daily.
  4. Haemoglobin < 120 g/L (sample no older than 3 months).
  5. Known bleeding disorders, including coagulopathies.
  6. Known allergies to investigational anaesthetic drugs (e.g., bupivacaine, remifentanil, or propofol).
  7. Neurological conditions with persistent motor or sensory deficits.
  8. Localised infections at the spinal injection site.
  9. Determined by the surgical or anaesthesia team to be unsuitable for trial participation and/or outpatient surgery.

  10. Women of childbearing potential (i.e., those who are fertile, following menarche and until becoming post-menopausal, unless permanently sterile)

    1. Who are not willing to use a highly effective method of contraception judged by the investigator, from the time of signing the informed consent, OR
    2. Who has a positive pregnancy test at enrolment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: General Anaesthesia (GA)
Participants randomized to this arm will receive general anaesthesia during outpatient primary total knee or total hip arthroplasty. General anaesthesia is administered using total intravenous anaesthesia with short-acting agents, primarily propofol and remifentanil, delivered intravenously according to routine clinical practice. Perioperative care apart from the assigned anaesthetic technique follows standard clinical protocols at each study site.
Drug: General Anaesthesia
General anaesthesia is administered using total intravenous anaesthesia with short-acting agents, primarily propofol and remifentanil. Anaesthesia is delivered intravenously using target-controlled or rate-controlled infusion systems according to routine clinical practice. Airway management and adjunct medications are provided as clinically indicated. The intervention is limited to the intraoperative period, and all other perioperative care follows standard clinical protocols at each study site.
Other Names:
  • TIVA
  • Total Intravenous Anaesthesia
  • Propofol-Remifentanil Anaesthesia
Experimental: Spinal Anaesthesia (SA)
Participants randomized to this arm will receive spinal anaesthesia during outpatient primary total knee or total hip arthroplasty. Spinal anaesthesia is administered as a single-shot intrathecal injection of bupivacaine. Optional intrathecal opioid adjuncts and light intravenous sedation may be used at the discretion of the anaesthesiologist to ensure patient comfort. All other perioperative care follows standard clinical practice at each study site.
Drug: Spinal Anesthesia (bupivacaine)
Spinal anaesthesia is administered as a single-shot intrathecal injection of bupivacaine prior to surgery. Optional intrathecal opioid adjuncts, with fentanyl or sufentanil, may be used to enhance analgesia according to routine clinical practice. Light intravenous sedation may be provided if needed for patient comfort. The intervention is limited to the intraoperative period, and all other perioperative care follows standard clinical protocols at each study site.
Other Names:
  • Spinal Block
  • Neuraxial Anaesthesia
  • Intrathecal Anaesthesia

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Successful Same-Day Discharge
Time Frame: Day of surgery to 48 hours after discharge
Successful same-day discharge is defined as discharge from the hospital on the day of surgery without readmission within 48 hours after discharge. Discharge readiness is assessed by the treating clinical team according to routine clinical criteria. Readmissions are identified through medical record review and patient follow-up.
Day of surgery to 48 hours after discharge

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time From Start of Anaesthesia to Start of Surgery
Time Frame: Day of surgery
Elapsed time from initiation of anaesthesia to the start of surgical incision, recorded intraoperatively.
Day of surgery
Time to Discharge From Post-Anaesthesia Care Unit (PACU)
Time Frame: From intervention to time of discharge from PACU
Time from the start of surgery to discharge from the postoperative recovery unit (Phase II), based on predefined discharge criteria.
From intervention to time of discharge from PACU
Time to Fulfilment of Hospital Discharge Criteria
Time Frame: During the hospital stay for surgery.
Time from the start of surgery to fulfilment of predefined criteria for discharge from hospital (Phase III), assessed by the clinical care team.
During the hospital stay for surgery.
Time to First Successful Mobilisation
Time Frame: During the hospital stay for surgery.
Time from the start of surgery to first successful mobilisation, defined as the ability to walk with tolerable pain, and to ascend or descend stairs if applicable.
During the hospital stay for surgery.
Opioid Consumption
Time Frame: Day of surgery to postoperative day 35
Postoperative opioid use converted to oral morphine equivalents (OME), recorded during hospital stay and reported by patients after discharge.
Day of surgery to postoperative day 35
Quality of Recovery (QoR-15)
Time Frame: Postoperative day 1 to postoperative day 35
Patient-reported quality of postoperative recovery measured using the Quality of Recovery-15 (QoR-15) questionnaire.
Postoperative day 1 to postoperative day 35
Postoperative Pain
Time Frame: Day of surgery to postoperative day 35
Postoperative pain assessed using the Numeric Rating Scale (NRS) during hospital stay for surgery.
Day of surgery to postoperative day 35
Pain during recovery
Time Frame: Baseline and, postoperative day 1 to postoperative day 35
Pain, measured with items 11 and 12 of QoR-15 questionnarie
Baseline and, postoperative day 1 to postoperative day 35
Functional Outcome After Surgery
Time Frame: Baseline, 4 weeks, 6 months, and 12 months postoperatively
Patient-reported functional outcomes assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS) for knee arthroplasty and the Hip disability and Osteoarthritis Outcome Score (HOOS) for hip arthroplasty.
Baseline, 4 weeks, 6 months, and 12 months postoperatively
Adverse Events and Serious Adverse Events
Time Frame: Start of anaesthesia to postoperative day 3
Incidence, severity, and frequency of adverse events and serious adverse events related to the perioperative period.
Start of anaesthesia to postoperative day 3
Predefined adverse outcomes
Time Frame: Day of surgery to 35 days postoperativly
Incidence and frequency of predefined adverse outcomes.
Day of surgery to 35 days postoperativly
Blood transfusions
Time Frame: During the hospital stay for surgery.
Units of blood transfusesd
During the hospital stay for surgery.
Patient Experiences of Anaesthesia and Recovery
Time Frame: 14 to 60 days after surgery
Patient-reported experiences of anaesthesia and postoperative recovery explored through semi-structured qualitative interviews.
14 to 60 days after surgery
Cost-Effectiveness (Incremental Cost-Effectiveness Ratio)
Time Frame: Baseline to 12 months postoperatively
Incremental cost-effectiveness ratios (ICERs) comparing general anaesthesia and spinal anaesthesia, calculated as differences in total costs divided by differences in quality-adjusted life years (QALYs) gained. QALYs are derived from EQ-5D-5L measurements.
Baseline to 12 months postoperatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Region Örebro County

Collaborators

Region Skane
Örebro University, Sweden

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

December 31, 2029

Study Completion (Estimated)

December 31, 2029

Study Registration Dates

First Submitted

December 16, 2025

First Submitted That Met QC Criteria

January 2, 2026

First Posted (Estimated)

January 12, 2026

Study Record Updates

Last Update Posted (Estimated)

January 12, 2026

Last Update Submitted That Met QC Criteria

January 2, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • GASPS
  • 2024-520127-89-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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