Hip arthroscopy for femoroacetabular impingement with 10-year minimum follow-up. / Artroscopia de cadera como tratamiento del choque femoroacetabular con seguimiento mínimo de 10 años.

PURPOSE: To determine outcomes after hip arthroscopy (HA) for femoroacetabular impingement (FAI) at a minimun 10-year follow up and identified risk factors for revision surgery. METHODS: Retrospective study of a prospective database of patients undergoing HA between January 2010 and December 2011. Rim chondral injuries were evaluated using the acetabular labral articular disruptions system (ALAD). Clinical and radiological data was obtained. Cumulative survival was estimated by Kaplan-Meier and a multivariate Cox proportional hazards model. RESULTS: Seventy-four patients were included in the study. Mean follow-up was 132 months. There was statistically significant improvement from preoperative PROs at latest follow-up. Seventeen patients (23.9%) underwent revision surgery. Odds ratio for revision surgery was 8.08 in a patient above 40 years old, 7.57 in a patient Tönnis greater than 1, and 4.25 in a patient ALAD 2-3. Cumulative survivorship rate at 10 years was 77.8%, with a 45.4% for patients with Tönnis grade greater than 1 in front of 85.2% for patients with Tönnis grade of 1 or less (P<.001). Risk factor for revision surgery was preoperative degree of osteoarthrosis (P=.02). CONCLUSION: Cumulative survivorship rate at 10 years was 45.4% for patients with Tönnis grade greater than 1 in front of 85.2% for patients with Tönnis grade of 1 or less (P<.001). Age, chondral injuries, and degree of osteoarthrosis would increase the risk for revision surgery.

[Translated article] Hip arthroscopy for femoroacetabular impingement with 10-year minimum follow-up.

PURPOSE: To determine outcomes after hip arthroscopy (HA) for femoroacetabular impingement (FAI) at a minimun 10-year follow up and identified risk factors for revision surgery. METHODS: Retrospective study of a prospective database of patients undergoing HA between January 2010 and December 2011. Rim chondral injuries were evaluated using the acetabular labral articular disruptions system (ALAD). Clinical and radiological data was obtained. Cumulative survival was estimated by Kaplan-Meier and a multivariate Cox proportional hazards model. RESULTS: Seventy-four patients were included in the study. Mean follow-up was 132 months. There was statistically significant improvement from preoperative PROs at latest follow-up. Seventeen patients (23.9%) underwent revision surgery. Odds ratio for revision surgery was 8.08 in a patient above 40 years old, 7.57 in a patient Tönnis greater than 1, and 4.25 in a patient ALAD 2-3. Cumulative survivorship rate at 10 years was 77.8%, with a 45.4% for patients with Tönnis grade greater than 1 in front of 85.2% for patients with Tönnis grade of 1 or less (p<.001). Risk factor for revision surgery was preoperative degree of osteoarthrosis (p=.02). CONCLUSION: Cumulative survivorship rate at 10 years was 45.4% for patients with Tönnis grade greater than 1 in front of 85.2% for patients with Tönnis grade of 1 or less (p<.001). Age, chondral injuries, and degree of osteoarthrosis would increase the risk for revision surgery.

A relativistic type Ibc supernova without a detected gamma-ray burst.

Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported.

Determination of the Neutron Lifetime Using Magnetically Trapped Neutrons.

We report progress on an experiment to measure the neutron lifetime using magnetically trapped neutrons. Neutrons are loaded into a 1.1 T deep superconducting Ioffe-type trap by scattering 0.89 nm neutrons in isotopically pure superfluid (4)He. Neutron decays are detected in real time using the scintillation light produced in the helium by the beta-decay electrons. The measured trap lifetime at a helium temperature of 300 mK and with no ameliorative magnetic ramping is substantially shorter than the free neutron lifetime. This is attributed to the presence of neutrons with energies higher than the magnetic potential of the trap. Magnetic field ramping is implemented to eliminate these neutrons, resulting in an [Formula: see text] trap lifetime, consistent with the currently accepted value of the free neutron lifetime.