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NCT Number: NCT07134036

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

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.

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Key information

Conditions

Osteoarthritis, Hip Arthritis Bone Diseases Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Developmental Dysplasia of the Hip Femur Head Necrosis Hip Dislocation Joint Diseases Joint Dislocations Musculoskeletal Abnormalities Musculoskeletal Diseases Necrosis Osteoarthritis Osteonecrosis Pathologic Processes Pathological Conditions, Signs and Symptoms Rheumatic Diseases

Age range

20 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

China Medical University Hospital

Taichung, 台中市, 404, Taiwan

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Navigation system

Device

Patients underwent total hip arthroplasty via the direct anterior approach using a computer navigation system to assist in intraoperative limb length measurement.

Conventional Total Hip Arthroplasty

Procedure

Patients underwent total hip arthroplasty via the direct anterior approach conventionally.

Primary outcomes

  1. Patients' Expectation Gap (PEG)

    Time frame: 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 outcomes

  1. Surgeons' Expectation Gap (SEG)

    Time frame: Intraoperative and 3 months postoperatively

    Difference between intraoperative navigation leg length measurement (mm) and postoperative radiographic leg length change (mm).

  2. Outlier Rate (>10 mm PEG)

    Time frame: 3 months postoperatively

    Percentage of patients with Patients' Expectation Gap greater than 10 mm.

  3. WOMAC Pain Score Change

    Time frame: Baseline, 3 weeks postoperatively, 3 months postoperatively

    Change in WOMAC pain subscale score (0-20, lower scores indicate less pain) from baseline.

  4. WOMAC Stiffness Score Change

    Time frame: Baseline, 3 weeks postoperatively, 3 months postoperatively

    Change in WOMAC stiffness subscale score (0-8, lower scores indicate less stiffness) from baseline.

  5. WOMAC Function Score Change

    Time frame: Baseline, 3 weeks postoperatively, 3 months postoperatively

    Change in WOMAC function subscale score (0-68, lower scores indicate better function) from baseline.

  6. Fluoroscopy Execution Time

    Time frame: Intraoperative

    Duration of intraoperative fluoroscopy use (seconds).

  7. Operative Time

    Time frame: Intraoperative

    Duration of total surgical procedure (minutes).

  8. Blood Loss

    Time frame: Intraoperative

    Total intraoperative blood loss (milliliters).

  9. Length Change

    Time frame: Baseline and 3 months postoperatively

    Difference in radiographic leg length pre- and postoperatively (mm).

Sponsors and collaborators

Lead sponsor

China Medical University Hospital

Other

Registry information

Official study title

Optimizing Limb Length Discrepancy in Navigated Total Hip Arthroplasty Through the Direct Anterior Approach on a Traction Table

Important dates

Study start
2021
Primary completion
2021
Study completion
2021
First posted
Aug 21, 2025
Registry last updated
Aug 21, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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