Midterm clinical and radiological outcomes of total hip arthroplasty in protrusio acetabuli, using novel technique of head of femur as an allograft

Abstract

Purpose: To assess outcomes of total hip arthroplasty (THA) in hip protrusion with acetabular defect grade 2 or more, using a novel technique of femoral head used as autograft, without the use of any protrusio ring, wire mesh, or cage.

Methodology: This case series included seven patients, with age 18 years or more and grade 2 or more protrusio acetabuli, who underwent total hip arthroplasty by a single fellowship-trained surgeon between 2019 and 2024. Patient demographics as age, sex, comorbidities, body mass index (BMI), protrusio grade, etiology, bearing surfaces, along with clinical findings such as intra- and post-operative complications, oxford hip score (OHS), follow up duration etc. were recorded. The Mann–Whitney U test compared functional outcomes between dual mobility and fixed bearing implants, while Spearman’s rank correlation assessed associations between BMI and Oxford hip Score, and between protrusio grade and Oxford hip score.

Results: Seven female patients were included, with a mean age of 51.9 years and mean body mass index of 29.9 kg/m². Five patients had bilateral disease, with two undergoing single-stage bilateral total hip arthroplasty. Etiologies included rheumatoid arthritis (n=3), prior femoral neck fracture (n=1), history of tuberculosis hip (n=1), steroid and immunosuppressive use (n=1), and unknown cause (n=1). Hypertension was the most frequently observed comorbidity (43%). Mean follow-up was 28.9 months. No complications such as infection, dislocation, aseptic loosening, or periprosthetic fracture were observed. All autologous grafts demonstrated radiographic incorporation. The mean Oxford Hip Score was 39.9, with good (71.4%) to excellent (28.6%) outcomes in all patients. Functional outcomes did not differ between dual mobility and fixed bearing implants (p=1.00). Moderate positive correlations were observed between OHS and BMI (ρ = 0.625) and between OHS and protrusion grade (ρ = 0.670).

Conclusion: Novel technique of using femur head autograft is an excellent biological method to fill acetabular medial defects during THA, while avoiding complications related to reinforcement devices.