Minimum 2-Year Outcomes of a Novel 3D-printed Fully Porous Titanium Acetabular Shell in Revision Total Hip Arthroplasty.

Background: Fully porous acetabular shells are an appealing choice for patients with extensive acetabular defects undergoing revision total hip arthroplasty (rTHA). This study reports on the early outcomes of a novel 3-D printed fully porous titanium acetabular shell in revision acetabular reconstruction. Methods: A multicenter retrospective study of patients who received a fully porous titanium acetabular shell for rTHA with a minimum of 2 years of follow-up was conducted. The primary outcome was rate of acetabular revision. Results: The final study cohort comprised 68 patients with a mean age of 67.6 years (standard deviation 10.4) and body mass index of 29.5 kg/m2 (standard deviation 5.9). Ninety-four percent had a preoperative Paprosky defect grade of 2A or higher. The average follow-up duration was 3.0 years (range 2.0-5.1). Revision-free survivorship at 2 years was 81% for all causes, 88% for acetabular revisions, and 90% for acetabular revision for aseptic acetabular shell failure. Eight shells were explanted within 2 years (12%): 3 for failure of osseointegration/aseptic loosening (4%) after 15, 17, and 20 months; 3 for infection (4%) after 1, 3, and 6 months; and 2 for instability (3%). At the latest postoperative follow-up, all unrevised shells showed radiographic signs of osseointegration, and none had migrated. Conclusions: This novel 3-D printed fully porous titanium shell in rTHA demonstrated good survivorship and osseointegration when used in complex acetabular reconstruction at a minimum of 2 years. Level of evidence: IV, case series.

Minimal invasive posterior total hip arthroplasty: are 6 weeks of hip precautions really necessary?

INTRODUCTION: Postoperative hip dislocations have been reported in 0.5 to 10.6 % of patients after primary posterolateral total hip arthroplasty (THA). Hip precautions are currently recommended for 6 weeks postoperatively to reduce early dislocation and facilitate healing of the posterior soft tissue repair. MATERIALS AND METHODS: To determine the impact of a modified 4-week precaution protocol on the dislocation rate, 698 consecutive patients (797 hips) operated by a single surgeon between September 2008 and December 2012 were retrospectively evaluated. All patients had a standard THA using a minimal invasive posterior approach with posterior soft tissue repair and 28-36-mm head size. 98.7 % of the patients were available for follow-up. RESULTS: There were eight (1 %) dislocations in 797 hips in the first 12 months after surgery with 4 weeks of hip precautions. The average time to dislocation was 7.5 weeks after surgery (range 1.0-16.9 weeks); two dislocations (25 %) took place in the first 4 weeks. CONCLUSIONS: Shortening the time of posterolateral hip precautions from 6 to 4 weeks after surgery does not increase the risk of postoperative dislocation.

Elderly patients with pelvic fracture: interventions and outcomes.

We examined the outcome of elderly trauma patients with pelvic fractures. Patients 65 years of age and older (elderly) with pelvic fractures were retrospectively compared with patients younger than 65 years with pelvic fractures and also with elderly patients without fracture. Over the study period, 1223 patients sustained a pelvic fracture (younger than 65 years, n=1066, 87.2%; elderly, n=157, 12.8%). These patients were also compared with 1770 elderly patients with blunt trauma without fracture. Although the pelvic fracture patients were equally matched for Injury Severity Score (21.2 +/- 13.4 nonelderly vs. 20.5 +/- 13.6 elderly), hospital length of stay was increased in the elderly (12.5 +/- 13.1 days vs. 11.5 +/- 14.1 days) and they had a higher mortality rate (20.4% [32 of 157] vs. 8.3% 88 of 10661). The elderly without fracture also had a higher mortality rate when compared with the younger patients (10.9% [191 of 1760]; P < 0.03). The elderly were more likely to die from multisystem organ failure (25.0% [eight of 32] vs. 10.2% [nine of 88]), whereas the nonelderly group was more likely to die from exsanguination (45.5% [40 of 88] younger than 65 years vs. 21.9% [seven of 32] 65 years or older; P < 0.05). Elderly patients with pelvic fracture have worse outcomes than their younger counterparts despite aggressive management at a Level I trauma center.

Detecting neuronal activity changes using an interspike interval algorithm compared with using visual inspection.

A universally accepted method for efficiently detecting neuronal activity changes (NACs) in neurophysiological studies has not been established. Visual inspection is still considered to be one of the most reliable methods, although it is limited when it is used for analyzing large quantities of data. In this study, an algorithm that considers interspike intervals (ISIs) was developed to define the onset of NACs. Two criteria, involving the mean and the standard deviation (S.D.) of the ISIs during a control period, were used in the ISI algorithm to evaluate the NACs that occurred during a detection period. The first, an ISI decrease of more than 1 S.D. from the mean ISI of the control period, proved to be an effective criterion for qualifying the increased NACs (firing rate increases). The second, an ISI increase greater than 3 S.D.s, efficiently demarcated periods of decreased NACs (firing rate decreases). Statistically significant correlations between the detection of NAC onset times by the ISI algorithm and the detection of those times by visual inspections were observed after offline analyses of recorded neuronal activity. The present results suggest that this ISI algorithm is a reliable and efficient way of defining the onset of NACs.