RESUMEN
OBJECTIVE: The relationship between the surgical approach used for hemiarthroplasty and periprosthetic bone mineral density (BMD) is not well understood. We have previously described a decrease in BMD 1 year postoperatively. Here, we assessed the medium-term changes in periprosthetic BMD. METHODS: We performed a follow-up study of patients with femoral neck fracture (FNF) who underwent uncemented hemiarthoplasty using a direct lateral or anterolateral approach. Dual-energy X-ray absorptiometry (DXA) was used to evaluate the changes in BMD in 23 patients over 5 years. RESULTS: A mean 6% loss of total BMD occurred over 1 year, but between 1 and 5 years, BMD was restored to the baseline value. The mean total BMD in the anterolateral group had decreased by 2% after 3 months and 3% after 12 months, and increased by 2% after 5 years, vs. decreases of 7%, 8%, and 3% for the direct lateral group. Between 1 and 5 years, BMD increased in Gruen zones 2, 3, 4, 5, and 6 in both groups. There was a significantly larger increase in zone 4 in the lateral group (4%) than the anterolateral group. CONCLUSION: The surgical approach affects periprosthetic BMD in patients with FNF. Furthermore, BMD is restored to the baseline value 5 years postoperatively.ClinicalTrials.gov registration number: NCT03753100.
Asunto(s)
Absorciometría de Fotón , Densidad Ósea , Fracturas del Cuello Femoral , Humanos , Femenino , Masculino , Anciano , Fracturas del Cuello Femoral/cirugía , Fracturas del Cuello Femoral/diagnóstico por imagen , Estudios de Seguimiento , Persona de Mediana Edad , Resultado del Tratamiento , Anciano de 80 o más Años , Hemiartroplastia/métodos , Artroplastia de Reemplazo de Cadera/métodos , Artroplastia de Reemplazo de Cadera/efectos adversosRESUMEN
Background and purpose - The loss of bone mineral in the proximal femur following hip arthroplasty may increase the fracture risk around uncemented stems. We hypothesized that the surgical approach to the hip might influence bone mineral changes around the femoral stem in patients with a femoral neck fracture (FNF). Patients and methods - This was a pre-specified subgroup analysis (n = 51) of an ongoing randomized trial (n = 120) in patients with FNF. Participants were allocated to an uncemented hemiarthroplasty inserted through a direct lateral (Hardinge) approach or an anterolateral (modified Watson-Jones) approach. The 51 patients (mean age 83 (70-90) years, 33 women) were measured by dual-energy X-ray absorptiometry (DXA) to assess changes in periprosthetic bone mineral density (BMD). Results - The mean change in total BMD differed between groups at 12 months in favor of the anterolateral group (4.8%, 95% CI 0.0-9.6; p = 0.05). DXA at 3 months displayed BMD loss in the proximal Gruen zones in the lateral group compared with the anterolateral group. Zone 1 (-5.0% vs. 2.7%), zone 2 (-4.3% vs. 4.1%), zone 6 (-6.5% vs. 0.0%) and zone 7 (-11% vs. -2.4%, all p < 0.05). Interpretation - DXA measurements in this study indicate that surgical approach to the hip influences periprosthetic BMD. Clinical implications remain uncertain. Our conclusions should be interpreted with caution as we did not perform adjustments for multiple tests, possibly leading to inflation of false-positive findings.