RESUMEN
BACKGROUND: Radiographic outcomes after total hip arthroplasty (THA) have been linked to clinical outcomes. The direct anterior approach (DAA) for THA has been criticized by some for providing limited exposure and compromised implant position but allows for routine use of intraoperative fluoroscopy. We sought to determine whether radiographic measurements differed by THA approach using prospective cohorts. METHODS: Two reviewers blinded to surgical approach examined 194 radiographs, obtained 4-6 weeks after primary THA, and obtained measurements for acetabular inclination angle, acetabular anteversion, radiographic limb length discrepancy (LLD), and femoral offset. All surgeries were performed at a tertiary academic medical center in rural New England by an experienced fellowship-trained arthroplasty surgeon. Measurements for inclination angle, anteversion, LLD, and offset were made into binary yes/no responses based on whether the mean measurement (between the 2 reviewers) was acceptable or not based on established criteria. Multivariate logistic regression analyses were performed using preoperative and intraoperative characteristics to identify predictors of acceptability for each measurement. RESULTS: The DAA group had higher rates of acceptable acetabular angle (96 vs 85%, P = .005) and was protective against an unacceptable angle in an adjusted predictive model (odds ratios 0.16, P = .005). There were no significant differences between approaches for acceptable anteversion, LLD, or offset. Body mass index of 30-34 was associated with higher odds of unacceptable inclination angle compared to the nonobese group (adjusted odds ratio, 6.82, P = .013). CONCLUSION: DAA for THA was associated with lower odds of unacceptable inclination angle compared to the posterior approach, with no differences in anteversion, LLD, or offset.
Asunto(s)
Acetábulo/diagnóstico por imagen , Acetábulo/cirugía , Artroplastia de Reemplazo de Cadera/métodos , Articulación de la Cadera/diagnóstico por imagen , Articulación de la Cadera/cirugía , Anciano , Anciano de 80 o más Años , Femenino , Fémur/cirugía , Fluoroscopía , Prótesis de Cadera , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Estudios Prospectivos , Radiografía , Resultado del TratamientoRESUMEN
A safe zone for acetabular component positioning in hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and acetabular inclination angle (AIA). For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 µg/L. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. Seven hundred sixty-one hip resurfacing cases are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists score, combined range of motion, diagnosis, age, gender, implant brand, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels. These findings apply to sub hemispheric metal-on-metal bearings with similar coverage arcs as the Biomet and Corin hip resurfacing brands. Additional problems may occur when these bearings are connected with trunions on stems for total hip arthroplasty.