Frontal QRS Axis Changes in Patients Undergoing Total Knee Arthroplasty With Spinal Anesthesia (FQRS-TKA)

A Prospective, Observational, Single-Center Study Evaluating Preoperative and Postoperative Changes in the Frontal QRS Axis on Electrocardiogram in Patients Undergoing Total Knee Arthroplasty Under Spinal Anesthesia

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07112313

Acronym

FQRS-TKA

Enrollment

Registered

2025-08-08

Start date

2025-09-01

Completion date

2025-10-01

Last updated

2025-12-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Spinal Anesthesia, Total Knee Arthroplasty

Keywords

Frontal QRS axis, Spinal anesthesia, Total knee replacement, Electrocardiogram (ECG), Postoperative ECG changes, Regional anesthesia, Orthopedic surgery

Brief summary

This prospective, single-center, observational study aims to evaluate changes in the frontal QRS axis on ECG before and after spinal anesthesia in patients undergoing total knee arthroplasty. The primary objective is to determine whether spinal anesthesia causes a significant alteration in the frontal QRS axis. A total of 80 patients will be enrolled, and preoperative and postoperative ECG measurements will be compared using paired t-test or Wilcoxon signed-rank test depending on data distribution.

Detailed description

This study will be conducted in the Department of Anesthesiology and Reanimation at Elazığ Fethi Sekin City Hospital. It is a prospective, observational, and single-center study designed to evaluate the impact of spinal anesthesia on the frontal QRS axis in patients undergoing elective total knee arthroplasty. The primary endpoint is the difference between preoperative and postoperative frontal QRS axis measurements. ECG recordings will be taken within 2 hours before and after surgery. Frontal QRS axis values will be automatically calculated by the ECG machine and verified manually. Inclusion criteria include patients aged 45-85 years, ASA class I-III, undergoing spinal anesthesia for elective knee replacement surgery, and able to obtain ECG recordings before and after the procedure. Patients with arrhythmias such as atrial fibrillation or pacemaker dependency, or those requiring postoperative ICU care or general anesthesia conversion will be excluded. The estimated sample size was calculated using G\*Power software. Based on previous studies, a minimum of 34 patients is required to detect a clinically significant change of 10 degrees in QRS axis, with a planned enrollment of 80 patients considering data loss. Statistical analysis will be conducted using SPSS 26.0. A p-value \<0.05 will be considered statistically significant.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

45 Years to 85 Years

Healthy volunteers

Inclusion criteria

* Aged between 45 and 85 years * ASA physical status I-III * Scheduled for elective total knee arthroplasty under spinal anesthesia * Able to tolerate 12-lead ECG before and within 2 hours after surgery

Exclusion criteria

* Known rhythm disorders affecting ECG axis (e.g., heart block, atrial fibrillation, pacemaker) * Conversion to general anesthesia * Admission to intensive care unit after surgery * Missing ECG data * Communication or mental disorders

Design outcomes

Primary

Measure	Time frame	Description
Change in Frontal QRS Axis After Spinal Anesthesia	From 2 hours before to 2 hours after surgery	To evaluate the difference in frontal QRS axis values on the electrocardiogram (ECG) before and after spinal anesthesia in patients undergoing total knee arthroplasty.

Countries

Turkey (Türkiye)

Outcome results