Developmental Dysplasia of the Hip, Femur Head Necrosis, Osteoarthritis, Hip
Conditions
Keywords
Direct Anterior Approach, Limb Length Discrepancy, Arthroplasty, Replacement, Hip, Surgery, Computer-Assisted, Surgical Navigation Systems
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.
Interventions
DEVICENavigation system
Patients underwent total hip arthroplasty via the direct anterior approach using a computer navigation system to assist in intraoperative limb length measurement.
PROCEDUREConventional total hip arthroplasty
Patients underwent total hip arthroplasty via the direct anterior approach conventionally.
Sponsors
China Medical University Hospital
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
20 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
| 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. |
| Surgeons' Expectation Gap (SEG) | Intraoperative and 3 months postoperatively | Difference between intraoperative navigation leg length measurement (mm) and postoperative radiographic leg length change (mm). |
| Operative Time | Intraoperative | Duration of total surgical procedure (minutes). |
| Blood Loss | Intraoperative | Total intraoperative blood loss (milliliters). |
| Length Change | Baseline and 3 months postoperatively | Difference in radiographic leg length pre- and postoperatively (mm). |
| Fluoroscopy Execution Time | Intraoperative | Duration of intraoperative fluoroscopy use (seconds). |
Countries
Taiwan
Outcome results
None listed