An observational study in Developmental Dysplasia of the Hip, Acetabular Bone Loss and Acetabular Fracture, sponsored by Ain Shams University. Not yet recruiting at 1 site in Egypt. Open to participants aged 16 Years and older. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by Ain Shams University · Observational
Total hip arthroplasty (THA) in patients with complex acetabular anatomy can be challenging because of abnormal bone structure, deformity, or bone loss. Accurate preoperative planning is important for selecting the appropriate acetabular component, determining its position, and achieving stable fixation.
This prospective study aims to evaluate whether patient-specific, CT-based three-dimensional (3D)-printed pelvic models improve preoperative planning in complex total hip arthroplasty compared with conventional radiographic and CT-based planning.
Patients undergoing complex primary or revision THA at Ain Shams University Hospitals will be included. For each patient, two preoperative plans will be prepared. Plan A will use conventional radiographs and CT images, while Plan B will additionally use a life-size 3D-printed pelvic model for surgical planning and simulation.
Both plans will be compared with the actual acetabular component size and orientation achieved during surgery. The study will also evaluate changes in surgical planning, restoration of the hip center, operative parameters, postoperative complications, functional outcomes, and the practical feasibility of 3D printing.
Patients will undergo postoperative follow-up for six months.
The study seeks to determine the additional value of 3D-printed pelvic models in improving planning accuracy and supporting surgical decision-making in complex hip replacement.
Background and Rationale
Complex acetabular anatomy represents a significant challenge in total hip arthroplasty (THA), particularly in patients with high-grade developmental dysplasia of the hip, post-traumatic acetabular deformities, and revision THA with acetabular bone loss.
Conventional preoperative planning relies on plain radiographs and computed tomography (CT). Although CT provides detailed anatomical information, irregular three-dimensional bone defects may remain difficult to assess using images displayed on a screen.
Patient-specific 3D-printed pelvic models provide physical representations of acetabular anatomy, allowing direct visualization, tactile assessment, implant templating, and simulation of reconstructive procedures before surgery.
Study Objectives
The primary objective is to compare conventional imaging-based planning with 3D-printed-model-assisted planning in predicting the acetabular component size and orientation achieved during THA.
Secondary objectives include evaluating hip center and offset restoration, changes in surgical strategy, agreement of preoperative Paprosky classification with intraoperative assessment, operative parameters, early postoperative outcomes, and the feasibility of producing and using 3D-printed models.
Study Design and Setting
This is a prospective, single-center, paired within-case comparative planning study conducted at Ain Shams University Hospitals, Department of Orthopaedic Surgery.
Eligible patients undergoing complex primary or revision THA will be consecutively recruited. Each included hip will undergo two sequential preoperative planning assessments using the same patient imaging data.
Preoperative Assessment
All patients will undergo clinical evaluation, baseline functional assessment, standard pelvic and hip radiographs, and thin-slice CT imaging.
Acetabular anatomy will be assessed using appropriate classifications, including the Crowe classification for developmental dysplasia and the Paprosky classification for revision acetabular bone defects.
Paired Planning Procedure
Plan A, Conventional Planning:
Surgeons will perform preoperative planning using standard radiographs and CT images without access to the physical 3D-printed model.
The planned acetabular cup size, inclination, anteversion, need for augmentation or reconstruction, fixation screw strategy, and surgeon confidence will be documented before the printed model is reviewed.
Plan B, 3D-Printed-Model-Assisted Planning:
CT DICOM data will be segmented and converted into a patient-specific three-dimensional pelvic model. A life-size physical model will be produced using 3D-printing technology.
Surgeons will review the model and perform hands-on planning or simulation, including assessment of acetabular defects, anticipated reaming, cup positioning, implant sizing, reconstruction options, and screw trajectories.
The revised surgical plan will then be documented using the same standardized planning parameters.
Paprosky Classification Assessment
For revision cases, two arthroplasty surgeons will independently classify acetabular defects using conventional imaging.
After an interval of at least two weeks, classification will be repeated using imaging combined with the 3D-printed model.
The intraoperative Paprosky classification recorded by the senior surgeon will serve as the reference for agreement analysis.
Operative Procedure
THA will be performed according to standard departmental surgical techniques using the final 3D-model-assisted planning strategy.
Intraoperative documentation will include actual acetabular component size, implant orientation, additional reconstruction requirements, fixation details, operative duration, estimated blood loss, complications, and deviations from the preoperative plan.
Assessment of Planning Accuracy
The predictions generated by Plan A and Plan B will be compared with the achieved surgical results.
Cup size agreement will be evaluated using exact matching and agreement within one implant size or approximately 2 mm.
Cup orientation agreement will be evaluated by calculating the absolute differences between planned and achieved inclination and anteversion.
Additional analyses will examine changes in implant selection, acetabular reconstruction strategy, screw planning, and agreement between preoperative and intraoperative defect classification.
Postoperative Follow-Up
Immediate postoperative radiographs will be obtained.
Patients will undergo follow-up examinations at six weeks, three months, and six months after surgery.
Clinical and radiographic assessments will document functional recovery, hip reconstruction, and complications including dislocation, loosening, fracture, infection, nerve injury, and thromboembolic events.
Feasibility Assessment
The study will document the time required for CT data processing, segmentation, printing, and surgical planning, together with model production costs and surgeon satisfaction.
Statistical Analysis
Continuous variables will be summarized using means and standard deviations or medians and interquartile ranges, as appropriate. Categorical variables will be presented as frequencies and percentages.
Paired continuous measurements will be compared using paired t-tests or Wilcoxon signed-rank tests according to data distribution.
Categorical paired outcomes will be analyzed using McNemar tests where appropriate. Agreement in acetabular defect classification will be evaluated using percentage agreement and Cohen's kappa statistics.
The findings will be used to assess the additional planning information provided by patient-specific 3D-printed pelvic models in complex THA.
60 studies on the registry are indexed under Developmental Dysplasia of the Hip; 18 are open to participants now.
This study's planned enrollment of 15 is below the median of 72 across 21 observational studies indexed under Developmental Dysplasia of the Hip.
Browse Developmental Dysplasia of the Hip studies →Ain Shams University is the lead sponsor of 1,950 studies on the registry; 429 are open to participants now.
Of its 35 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
The study population will consist of patients aged 16 years or older undergoing primary or revision total hip arthroplasty at Ain Shams University Hospitals for complex acetabular anatomy.
Eligible patients will include those with high-grade developmental dysplasia of the hip (Crowe III-IV), revision total hip arthroplasty with acetabular bone loss (Paprosky IIC-IIIB), or post-traumatic acetabular pathology.
Consecutive eligible patients will be recruited during the study period. The anticipated sample size is approximately 10 hips. All participants will undergo preoperative assessment and postoperative follow-up for six months.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Patients indicated for primary or revision total hip arthroplasty with complex acetabular anatomy, including at least one of the following:
Exclusion Criteria:
Patients undergoing primary or revision total hip arthroplasty (THA) for complex acetabular anatomy, including high-grade developmental dysplasia of the hip (Crowe III-IV), revision THA with acetabular bone loss (Paprosky IIC-IIIB), and post-traumatic acetabular deformities. Each included case will undergo two sequential preoperative planning assessments: conventional radiographic and CT-based planning (Plan A), followed by CT-based 3D-printed pelvic model-assisted planning (Plan B). The accuracy of both plans will be compared with the achieved surgical results. Patients will be followed postoperatively for six months.
Other: Conventional Imaging-Based Preoperative Planning · Other: CT-Based 3D-Printed Pelvic Model-Assisted Planning
Preoperative planning of total hip arthroplasty using standard pelvic and hip radiographs and CT images without reviewing the 3D-printed pelvic model. The surgeon will document the planned acetabular cup size, inclination, anteversion, anticipated need for augments or cages, screw fixation strategy, and confidence level (0-10). This initial plan (Plan A) will be recorded and locked before the 3D-printed model is reviewed.
Patient-specific, life-size 3D-printed pelvic models will be generated from preoperative CT DICOM data through image segmentation and 3D printing. Surgeons will use the models for anatomical assessment and hands-on simulation of acetabular reaming, cup sizing and positioning, augment or cage selection, and screw trajectory planning. The model-assisted plan (Plan B) will be documented and compared with Plan A and the achieved surgical results.
Exact Acetabular Cup Size Prediction Accuracy
The percentage of cases in which the planned acetabular cup size exactly matches the actual implanted cup size. Exact matching will be assessed separately for conventional imaging-based planning (Plan A) and 3D-printed-model-assisted planning (Plan B), using the intraoperative implant record as the reference.
Time frame: During surgery
Acetabular Cup Size Prediction Accuracy Within 2 mm
The percentage of cases in which the planned acetabular cup size is within 2 mm or one implant size of the actual implanted cup size. Accuracy will be calculated separately for Plan A and Plan B and compared using the intraoperative implant record.
Time frame: During surgery
Absolute Error in Acetabular Cup Inclination
The absolute difference, measured in degrees, between the planned acetabular cup inclination and the achieved postoperative cup inclination. Errors will be calculated separately for Plan A and Plan B using postoperative radiographic or CT measurements, allowing a paired comparison of planning accuracy.
Time frame: Immediate postoperative imaging
Absolute Error in Acetabular Cup Anteversion
The absolute difference, measured in degrees, between the planned acetabular cup anteversion and the achieved postoperative cup anteversion. Errors will be calculated separately for Plan A and Plan B using postoperative radiographic or CT measurements, allowing a paired comparison of planning accuracy.
Time frame: Immediate postoperative imaging
Changes in Preoperative Surgical Planning
Percentage of cases in which Plan B differs from Plan A in planned cup size, target cup orientation, augment or cage requirement, or screw fixation strategy. Each type of planning change will be recorded.
Time frame: During preoperative planning
Agreement of Paprosky Classification With Intraoperative Findin
Percentage agreement and Cohen's kappa between Paprosky classifications obtained from conventional imaging (Plan A) and 3D-model-assisted assessment (Plan B), compared with the intraoperative classification recorded by the senior surgeon.
Time frame: Preoperative assessment and during surgery SECONDARY OUTCOME
Restoration of Hip Center and Offset
Radiographic assessment of the hip center and hip offset before and after total hip arthroplasty. Measurements will be recorded in millimeters to evaluate postoperative anatomical restoration.
Time frame: Preoperative assessment and immediate postoperative imaging
Agreement Between Planned and Actual Acetabular Reconstruction
Agreement between the anticipated need for acetabular augments, buttresses, or cages in Plan A and Plan B and the reconstructive components actually used during surgery. Results will be reported by reconstruction category.
Time frame: During surgery
Operative Time
Duration of total hip arthroplasty, measured in minutes and recorded for each surgical case.
Time frame: During surgery
Estimated Intraoperative Blood Loss
Estimated volume of blood lost during total hip arthroplasty, measured in milliliters.
Time frame: During surgery
Incidence of Intraoperative Complications
Number and percentage of patients experiencing intraoperative complications during total hip arthroplasty, with the type of complication recorded.
Time frame: During surgery
Incidence of Postoperative Complications
Number and percentage of patients experiencing postoperative complications, including dislocation, loosening, fracture, infection, nerve palsy, and thromboembolic events.
Time frame: From surgery through 6-month postoperative follow-up
Change in Postoperative Hip Functional Score
Change from baseline in hip function assessed using the Harris Hip Score and/or Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), according to the functional instrument selected in the study protocol.
Time frame: Baseline, 6 weeks, 3 months, and 6 months postoperatively
Surgeon Confidence in Preoperative Planning
Surgeon-reported confidence in each preoperative plan, measured using a numeric rating scale from 0 to 10. Scores will be recorded separately for Plan A and Plan B.
Time frame: Immediately after completion of each preoperative plan
Number of Unplanned Implants Opened During Surgery
Number of additional or unplanned implants opened during surgery, including acetabular cups, liners, augments, cages, and screws, where inventory documentation is available.
Time frame: During surgery
Plan to share: Undecided
Start is estimated for Nov 2026; primary completion for May 2028, 18 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Developmental Dysplasia of the Hip →