Skeletal Maturity Might Not Be a Factor in Optimizing Outcomes in Total Hip Arthroplasty

Introduction Total hip arthroplasty (THA) is rarely indicated in the skeletally immature population. In these instances, there is concern for implant survival compared to the traditional older population. There has been a steady rise in the use of THA in the pediatric population due to improvements in surgical techniques. While the outcomes in THA for skeletally immature patients have been described in the literature, there are no population studies looking at this procedure in a skeletally immature individual. Therefore, the purpose of this study was to compare 10-year implant survivability following primary THA in skeletally mature versus skeletally immature patients. Methods Patients who underwent primary THA were identified using a large national database (PearlDiver). THA patients were then divided into presumed skeletally immature male patients (0-16 years), presumed skeletally mature male patients (17-21 years), presumed skeletally immature females (0-14 years), and presumed skeletally mature females (15-21 years). Multivariable analysis was conducted using Cox proportional hazards modeling to determine differences in the risk of revision for periprosthetic joint infection (PJI), mechanical loosening, dislocation/instability, and periprosthetic fracture (PPF). Results In total, 352 male patients (244 skeletally mature and 108 skeletally immature) and 409 female patients (350 skeletally mature and 59 skeletally immature) were identified. Compared to skeletally immature females, skeletally mature females had no higher risk of 10-year revision for all-cause, PJI, mechanical loosening, dislocation/instability, or PPF (P > 0.05 for all). Compared to skeletally immature males, skeletally mature males had no higher risk of 10-year revision for all-cause, PJI, mechanical loosening, dislocation/instability, or PPF (P > 0.05 for all). Conclusion Although THA occurred more commonly in patients above the presumed age of skeletal maturity, the lack of significantly different surgical outcomes suggests that younger age and presumed skeletal immaturity may not put patients at any further risk of implant failure. While further research is needed to understand the impact of age and skeletal maturity on outcomes of THA, these results indicate that the initial age of a THA may not be a factor in optimizing outcomes, and suggests that orthopedic surgeons need not delay surgery based on age or skeletal maturity alone.