Efficiency and Safety of Navigation Aids in Total Hip Arthroplasty With Direct Anterior Approach

Not Applicable

Completed

• Conditions: Osteoarthritis, Hip; Femur Head Necrosis; Developmental Dysplasia of the Hip

• Registration Number: NCT07134036
• Lead Sponsor: China Medical University Hospital

Brief Summary

This prospective clinical study aimed to evaluate the effectiveness of an imageless navigation system in total hip arthroplasty (THA) via the direct anterior approach (DAA) on a traction table for reducing functional limb length discrepancy (LLD) compared with conventional techniques. Seventy-two patients with advanced hip osteoarthritis, avascular necrosis, or developmental dysplasia of the hip undergoing THA between March 1, 2021 and September 30, 2021 were included. Functional LLD was assessed using a preoperative block test. Participants were assigned to the navigation or conventional group based on patient preference. Outcomes included operative parameters, intraoperative fluoroscopy time, limb length measurements, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores.

Detailed Description

This single-center prospective comparative study was conducted at the Joint Reconstruction Center of China Medical University Hospital between March 1, 2021 and September 30, 2021. Eligible participants were adults diagnosed with advanced hip osteoarthritis, avascular necrosis, or developmental dysplasia of the hip requiring THA. Exclusion criteria included prior hip joint infection, severe LLD requiring additional reconstructive procedures, significant spinal pathology affecting spinopelvic balance, or radiographs inadequate for measurement.

All procedures were performed via the direct anterior approach (DAA) on a traction table by the principal surgeon. Functional LLD was assessed preoperatively using a block test, with wooden blocks (5 mm increments) placed under the heel until the patient reported equal leg lengths.

Patients in the navigation group underwent THA with an imageless navigation system (Stryker OrthoMap Versatile Hip Navigation) to record intraoperative limb length change and acetabular cup positioning; the conventional group underwent standard THA without navigation.

Primary outcome was the patients' expectation gap (PEG), defined as the difference between preoperative functional LLD and postoperative radiographic limb length change. Secondary outcomes included intraoperative fluoroscopy time, WOMAC scores at baseline, 3 weeks, and 3 months postoperatively, and the proportion of outliers (PEG \> 10 mm).

The study was approved by the Research Ethics Committee of China Medical University Hospital (CMUH112-REC1-149). Written informed consent was obtained from all participants, and the study adhered to the Declaration of Helsinki.

Study Timeline

• Study Start: 2021-03-01
• Primary Completion: 2021-09-30
• Study Completion: 2021-09-30
• Study First Submitted: 2025-07-05
• Status Verified: 2025-08
• Study First Submitted QC: 2025-08-13
• Last Update Submitted: 2025-08-13
• Study First Posted: 2025-08-21
• Last Update Posted: 2025-08-21

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 72

Inclusion Criteria

• Clinical diagnosis of advanced hip osteoarthritis (OA) warranting total hip arthroplasty (THA)
• Clinical diagnosis of avascular necrosis (AVN) of the femoral head warranting total hip arthroplasty (THA)
• Clinical diagnosis of developmental dysplasia of the hip (DDH) warranting total hip arthroplasty (THA)

Exclusion Criteria

• Documented history of prior hip joint infection
• Severe limb length discrepancy requiring supplementary surgical interventions
• Significant spinal pathology affecting spinopelvic balance
• Radiographs in which the lesser trochanters and teardrops cannot be clearly defined

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Patients' Expectation Gap (PEG)	Baseline (preoperative) and 3 months postoperatively	Difference between preoperative functional leg length discrepancy (measured with block test, mm) and postoperative radiographic leg length change (mm).

Secondary Outcome Measures

Name	Time	Method
Surgeons' Expectation Gap (SEG)	Intraoperative and 3 months postoperatively	Difference between intraoperative navigation leg length measurement (mm) and postoperative radiographic leg length change (mm).
Outlier Rate (>10 mm PEG)	3 months postoperatively	Percentage of patients with Patients' Expectation Gap greater than 10 mm.
WOMAC Pain Score Change	Baseline, 3 weeks postoperatively, 3 months postoperatively	Change in WOMAC pain subscale score (0-20, lower scores indicate less pain) from baseline.
Fluoroscopy Execution Time	Intraoperative	Duration of intraoperative fluoroscopy use (seconds).
Blood Loss	Intraoperative	Total intraoperative blood loss (milliliters).
Length Change	Baseline and 3 months postoperatively	Difference in radiographic leg length pre- and postoperatively (mm).
WOMAC Stiffness Score Change	Baseline, 3 weeks postoperatively, 3 months postoperatively	Change in WOMAC stiffness subscale score (0-8, lower scores indicate less stiffness) from baseline.
WOMAC Function Score Change	Baseline, 3 weeks postoperatively, 3 months postoperatively	Change in WOMAC function subscale score (0-68, lower scores indicate better function) from baseline.
Operative Time	Intraoperative	Duration of total surgical procedure (minutes).

Trial Locations

Locations (1)

China Medical University Hospital; 🇨🇳 Taichung City, 台中市, Taiwan