EP6.5 Prosthetic hip replacement in young adults: a retrospective study of implant survival and radiographic and clinical outcomes in patients under 25

Abstract

Abstract Introduction Total hip arthroplasty (THA) in patients under 25 years of age represents a complex surgical field, in which high functional demands coexist with frequently altered anatomy and a lifetime risk of multiple revisions. Available literature is limited, highlighting the need for updated evidence. The present study aims to evaluate the data of a single center through three primary objectives: analysis of implant survival both overall and across different etiological subgroups (LLA, DCA, Perthes, SCFE); assessment of functional outcomes and radiographic comparison between standard and short femoral stems. Method A retrospective observational study was conducted on patients <25 years undergoing THA, recording implant survivorship, complications, osteolysis and revision procedures, functional outcomes using the modified Harris Hip Score (mHHS), WOMAC, and UCLA Activity Score. A comparative analysis between short and standard femoral stems was performed, along with subgroup (ALL, DDH, Perthes disease, SCFE). Results 74 patients (95 hips) aged 12–25 years were included, with a mean age of 19,16. 53 females (56%) and 42 males (44%); 30 cases of acute lymphoblastic leukemia (30%), 24 cases of developmental dysplasia of the hip (24%), 14 cases of SCFE (15%), and 8 cases of Legg-Calvé-Perthes disease (8%). Posterolateral approach was used in 69 cases (72%) and an anterior approach in 26 cases (28%). Short stems were implanted in 48% of cases, standard stems in 51%, and a revision stem in one patient. Overall implant survival was 98% at 1 year, 94% at 5 years, and 90% at 7 years, with minimal differences among etiological subgroups. Survival at 100 months was 96% in ALL and 100% in Perthes disease (limited by small sample size); in SCFE, one revision for metallosis occurred at 5 years (survivorship 92%); DDH showed intermediate results (95% at 100 months). Complications rate were reported. Five revision’s surgeries were recorded: one for ceramic liner fracture (1 month postoperatively); one stem revision due to recurrent dislocations (1 month); one stem revision for instability associated with patient growth (2 years); one acetabular revision for metallosis (5 years); and one acetabular revision for aseptic loosening (6 years). Clinical outcomes demonstrated significant functional improvement, with mean scores of mHHS 87, WOMAC 9.31, and UCLA 6.44, with no differences among etiologies. Comparison between short and standard stems showed no differences in complication or revision rates. However, a statistically significant difference in mHHS was observed, with slightly better scores in the short stem group (88.39 vs 84.71; p = 0.04). Conclusions THA in patients under 25 years provides significant functional improvement and good mid-term implant survivorship, although not free from comlpications, which seem to be higher than in adults. Stem length selection should be individualized, considering patient anatomy, bone growth, and the potential need for future revisions.