Posterior pelvic tilt evolution in patients undergoing total hip arthroplasty. A minimum 5-years follow-up clinico-radiological study. / Evolución de la inclinación pélvica a lo largo del tiempo en pacientes intervenidos de prótesis total de cadera. Estudio clínico-radiológico con un seguimiento mínimo de cinco años.

ABSTRACT

BACKGROUND AND OBJECTIVE: Pelvic tilt influences the relative position between total hip arthroplasty (THA) components. Changes in lumbar spine over time may affect clinical and radiological outcomes of THA during follow-up. We assessed the evolution of pelvic tilt and cup position after THA for a minimum follow-up of five years and the possible appearance of complications. MATERIAL AND METHODS: This retrospective study includes 48 patients operated between 2008 and 2012. Clinical data, complication and radiological analysis included sacro-femoral-pubic and acetabular abduction angles on the anteroposterior pelvic view; and cup anteversion angle on the lateral cross-table hip view according to Woo and Morrey. All assessments were done pre-operatively and at 6 weeks, one, two and five years post-operatively. RESULTS: Mean sacro-femoral-pubic decreased from 60.6∘ preoperatively to 58.8∘ at five years (p > .05), more in females (from 63.3 to 59.3) than males (58.7 to 58.3). Acetabular abduction increased from 47.3 at six-week postoperatively to 48.2 at five years (p > .05) and acetabular anteversion varied from 24.3∘ to 36.1∘ (p < .04). There were four dislocations one late recurrent dislocation which required cup revision. CONCLUSION: Despite the sacro-femoral-pubic angle tendency to decrease and anteversion tendency to increase after five years, larger studies with longer follow-up are needed to confirm the potential increasing in long term complications.