Minimum 10-year follow-up of micro-arc oxidation coating on a cementless grit-blasted tapered-wedge stem of total hip arthroplasty: a multicentre study.

BACKGROUND: Recently, a femoral stem treated with grit-blasting and micro-arc oxidation (MAO) coating has commercialised but medium-term follow-up studies are lacking. The aim of this study was to report the outcome of a grit-blasted and MAO-coated femoral component designed as a straight, double-wedged, tapered stem with a rectangular cross-section with minimum 10 years follow-up. METHODS: Between March 2006 and December 2008, 309 primary total hip arthroplasties using a grit-blasted and MAO-coated femoral component were performed by 3 experienced hip surgeons in 3 hospitals. At minimum 10 years after index THA, 299 hips were living, 10 hips were deceased, and 65 hips were lost to follow-up or had a follow-up period <10 years. Finally, 234 hips were enrolled in this study. RESULTS: Mean duration of clinical follow-up was 129.6 months. The mean Harris Hip Score was improved from 46.9 to 88.4 at the final follow-up. 4 hips were revised for 2 aseptic femoral loosening, 1 aseptic acetabular cup loosening and 1 late infection. 3 hips were revised for a periprosthetic femoral fracture requiring a femoral component revision. The average time to revision was 51.6 (range 0-148) months. Kaplan-Meier survivorship analysis with an end point of revision for any reason demonstrated a survival rate of 97.4% at 10 years. Survival was 98.7% with revision for aseptic loosening as the endpoint. CONCLUSIONS: The outcomes of a cementless grit-blasted and MAO-coated tapered-wedge stem of THA were excellent to satisfactory after a follow-up of at least 10 years.

Is there a correlation between fragility fractures of the pelvis (FFP) and the morphology of the true pelvis in geriatric patients?

PURPOSE: There has been no prior study to demonstrate the relationship between the occurrence of fragility fractures of the pelvis and its morphology. The aim of this study was to investigate the effect of pelvic morphology on fragility fractures of the pelvis caused by low-energy trauma in elderly female patients. MATERIALS AND METHODS: As a normal pelvis group, 643 female patients over 65 years of age who underwent pelvic CT were collected. Using three-dimensional multiplanar reconstruction (3D-MPR) function of RadiAnt software, the DT (diameter of transverse true pelvis)/DS (diameter of sagittal true pelvis) values of normal pelvis were measured. Sorted in ascending order, the mean DT/DS value of normal pelvis was 1.13 ± 0.09. The values corresponding to the 25th percentile and the 75th percentile were 1.06 and 1.18, respectively. We arbitrarily named DT/DS values of 1.06 or less corresponding to lower than 25th percentile as 'Circle types', and DT/DS values of 1.18 or higher corresponding to higher than 75th percentile as 'Ellipse types'. Total of 76 female patients over 65 years of age who underwent 3D reconstructions of pelvic CT scans with fragility fractures of the pelvis, who fell into the criteria corresponding to FFP classification type II, were studied separately. Of the 76 female FFPs, two were FFP type IIa, 32 were FFP type IIb, and 42 were FFP type IIc. Their DT/DS was measured. RESULTS: Based on the above mentioned criteria, we classified the pelvis shape of 76 patients with fragility fracture of the pelvis type II. 33 patients (43.4%) were classified as circle types and eight patients (10.5%) were classified as ellipse types. The odds ratio of "circle type" for fragility fractures of pelvis type II was 4.1. CONCLUSION: With digital reconstruction and 3D measurement of normal adult pelvic CT scans, this study obtained a series of DT/DS values describing the shape of true pelvises. Circle-type true pelvis was found to be more common in patients with fragility fracture of the pelvis type II.