Prospective External Validation of an Early Prediction Model for Adverse Postoperative Pain Trajectories After Orthopedic Surgery

October 11, 2026 updated by: Lihua Peng, First Affiliated Hospital of Chongqing Medical University

Single-Center Prospective External Validation Study of an Early Prediction Model for Adverse Postoperative Pain Trajectories After Orthopedic Surgery

This prospective observational study will externally validate a previously developed and locked prediction model for identifying adult patients at risk of adverse postoperative pain trajectories after elective orthopedic surgery. Approximately 400 patients will be consecutively recruited at the First Affiliated Hospital of Chongqing Medical University.

Postoperative pain will be assessed during the first 48 hours after surgery using the 0-10 Numeric Rating Scale. Pain scores will be organized into eight consecutive 6-hour time windows to determine each participant's postoperative pain trajectory according to prespecified rules. Clinical information available at the predefined prediction time point will be entered into the locked prediction model to calculate each participant's predicted probability of an adverse pain trajectory.

The study will evaluate the model's discrimination, calibration, overall prediction performance, and potential clinical utility. The model will not be modified or retrained using data from this validation cohort. Individual prediction results will not be provided to patients or treating clinicians and will not be used to guide treatment during the study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a single-center, prospective, observational external validation study of an early prediction model for adverse postoperative pain trajectories in adult patients undergoing elective orthopedic surgery at the First Affiliated Hospital of Chongqing Medical University.

Eligible participants will receive routine perioperative care. The study will not assign any experimental treatment or alter the participants' surgical, anesthetic, analgesic, nursing, or rehabilitation management. Study personnel will collect prespecified clinical variables from patient interviews, electronic medical records, anesthesia information systems, nursing records, and standardized postoperative pain assessments.

The end of surgery will be defined as postoperative hour 0. Postoperative pain intensity will be assessed using the 0-10 Numeric Rating Scale during the first 48 hours after surgery. This period will be divided into eight consecutive 6-hour windows: 0-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-42, and 42-48 hours. When more than one valid pain score is available within a time window, the median value will be used for the primary analysis.

Before enrollment of the first participant, the prediction model, prediction time point, predictor definitions, variable coding, data-processing procedures, missing-data handling rules, model structure, model parameters and hyperparameters, and outcome classification rules will be locked. Data from the external validation cohort will not be used to reselect predictors, retune hyperparameters, redefine cutoffs, or otherwise modify the original model.

After completion of the 48-hour observation period and data verification, each participant's probability of developing an adverse postoperative pain trajectory will be calculated using the locked model. The observed postoperative pain trajectory will be determined independently according to the prespecified trajectory classification and mapping rules.

External model performance will be evaluated using the area under the receiver operating characteristic curve, Brier score, calibration curve, calibration intercept, and calibration slope. Additional analyses will include sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and decision curve analysis at prespecified risk thresholds. Exploratory analyses may describe model performance across major orthopedic surgical categories.

Model predictions will be calculated offline and will not be communicated to participants, surgeons, anesthesiologists, nurses, or other treating clinicians during the study. Prediction results will therefore not influence clinical management.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
400

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

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
      • Chongqing, China
        • Recruiting
        • The First Affiliated Hospital of Chongqing Medical University
        • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Adult patients undergoing elective orthopedic surgery at the First Affiliated Hospital of Chongqing Medical University who are expected to remain hospitalized for at least 48 hours after surgery. Eligible procedures include major categories of elective orthopedic surgery, such as spinal surgery, hip or knee arthroplasty, pelvic or extremity fracture fixation, and orthopedic corrective surgery. Participants will be prospectively and consecutively screened and enrolled according to the prespecified eligibility criteria.

Description

Inclusion Criteria:

  • Aged 18 to 90 years, regardless of sex.
  • Scheduled to undergo an eligible elective orthopedic surgical procedure at the First Affiliated Hospital of Chongqing Medical University.
  • Expected to remain hospitalized for at least 48 hours after surgery.
  • Conscious before surgery, with sufficient understanding and communication ability to understand and complete the 0-10 Numeric Rating Scale for pain.
  • Able and willing to provide written informed consent before any study-specific data collection.

Exclusion Criteria:

  • Younger than 18 years or older than 90 years.
  • Emergency surgery, unplanned surgery, or a surgical procedure outside the prespecified orthopedic surgical scope of the study.
  • Unable to reliably understand the study or complete the Numeric Rating Scale because of impaired consciousness, severe cognitive impairment, psychiatric disorder, persistent deep sedation, mechanical ventilation, severe hearing impairment, language or communication difficulties, or similar conditions.
  • Lacks full capacity to provide valid informed consent.
  • Concurrent participation in another clinical study that may affect pain assessment, analgesic treatment, or study outcomes.
  • Expected discharge or transfer within 48 hours after surgery, or inability to complete the main study observation because of clinical circumstances.
  • Any other condition that, in the investigator's judgment, makes the patient unsuitable for participation in the study.

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

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Prospective External Validation Cohort

Adult patients undergoing elective orthopedic surgery at the First Affiliated Hospital of Chongqing Medical University will be prospectively enrolled and followed for 48 hours after surgery. Postoperative pain scores and prespecified clinical variables will be collected according to the study protocol. All participants will receive routine perioperative care, and no treatment will be assigned or modified by the study investigators. The locked prediction model will be applied offline to evaluate the risk of an adverse postoperative pain trajectory.
Procedure: Elective Orthopedic Surgery

Participants will undergo elective orthopedic surgery as part of routine clinical care. The surgical procedure, anesthetic management, postoperative analgesia, nursing care, and rehabilitation plan will be determined by the treating clinical team according to standard practice. The study investigators will not assign, modify, or influence these treatments. The study will prospectively collect prespecified perioperative variables and postoperative pain assessments for external validation of a locked prediction model.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Proportion of Participants With an Adverse Postoperative Pain Trajectory
Time Frame: From the end of surgery through 48 hours postoperatively

Participants will be classified as having an adverse or non-adverse postoperative pain trajectory based on pain scores collected during the first 48 hours after surgery and the prespecified, locked trajectory classification and mapping rules. The number and percentage of participants classified as having an adverse postoperative pain trajectory will be reported.
From the end of surgery through 48 hours postoperatively

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Area Under the Receiver Operating Characteristic Curve (AUC)
Time Frame: Through 48 hours postoperatively

The area under the receiver operating characteristic curve (AUC) will be used to assess the discrimination of the locked prediction model for distinguishing participants with and without an adverse postoperative pain trajectory. The AUC ranges from 0.5, indicating no discrimination, to 1.0, indicating perfect discrimination. The AUC and its 95% confidence interval will be reported.
Through 48 hours postoperatively
Brier Score
Time Frame: Through 48 hours postoperatively

The Brier score will be used to evaluate the overall predictive performance of the locked prediction model by comparing predicted probabilities with the observed binary adverse postoperative pain trajectory outcome. Lower values indicate better overall predictive performance. The Brier score and its 95% confidence interval will be reported.
Through 48 hours postoperatively
Calibration Intercept
Time Frame: Through 48 hours postoperatively

Calibration intercept will be used to assess systematic overestimation or underestimation of predicted risk by the locked prediction model. A value of 0 indicates ideal calibration. The calibration intercept and its 95% confidence interval will be reported.
Through 48 hours postoperatively
Calibration Slope
Time Frame: Through 48 hours postoperatively

Calibration slope will be used to assess the agreement between the spread of predicted probabilities and observed outcomes. A value of 1 indicates ideal calibration. The calibration slope and its 95% confidence interval will be reported.
Through 48 hours postoperatively
Calibration Curve
Time Frame: Through 48 hours postoperatively

A calibration curve will be used to visually assess agreement between predicted probabilities of an adverse postoperative pain trajectory and observed outcome frequencies across the range of predicted risk. The calibration curve and its 95% confidence interval will be presented.
Through 48 hours postoperatively
Classification Performance at the Prespecified Risk Threshold
Time Frame: Through 48 hours postoperatively

Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the locked prediction model will be evaluated at the prespecified risk threshold and reported with 95% confidence intervals where applicable. The threshold will not be selected or optimized using the external validation cohort.
Through 48 hours postoperatively
Decision Curve Analysis
Time Frame: Through 48 hours postoperatively

Decision curve analysis will be used to evaluate the clinical net benefit of the locked prediction model across a prespecified range of clinically relevant risk thresholds, compared with strategies of treating all participants or treating no participants as being at increased risk.
Through 48 hours postoperatively
Distribution and Characteristics of Postoperative Pain Trajectory Classes
Time Frame: From the end of surgery through 48 hours postoperatively

The number and percentage of participants assigned to each prespecified postoperative pain trajectory class will be described. Class-specific mean pain trajectories over the first 48 postoperative hours and prespecified indicators of classification uncertainty will also be summarized.
From the end of surgery through 48 hours postoperatively

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
First Affiliated Hospital of Chongqing Medical University

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 7, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 23, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 23, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 29, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 15, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CQMUFAH-PT-EXT-2026-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared with external researchers because the study involves sensitive patient-level clinical information and is subject to institutional data protection and confidentiality requirements. Study data will be securely stored and accessible only to authorized study personnel. Aggregated, de-identified study findings will be disseminated through peer-reviewed scientific publications. Any future change to the IPD sharing plan will be subject to applicable ethical and institutional approvals.

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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