Squeaking and other noises in patients with ceramic-on-ceramic total hip arthroplasty.

INTRODUCTION: Noise in ceramic-on-ceramic (CoC) total hip arthroplasty (THA) is a potential symptom of abnormal bearing wear. Squeaking and other prosthetic hip noises are multi-factorial phenomena that can be analysed and may provide prognostic information. METHODS: 46 patients with noisy CoC bearings were investigated using X-ray, computed tomography and joint fluid analysis, and classified into either high or low risk of ceramic liner fracture groups according to previously published guidelines. Noise events from the bearings of 16 high risk cases which were subsequently revised were compared with 30 patients in the low risk control group who did not undergo revision. Noise events were analysed for their physical characteristics using a standardised protocol and classified as either low frequency and short duration 'clicking' or long duration and high frequency 'squeaking'. RESULTS: The peak frequency of squeaking during forward walking was significantly higher for patients in the case group who were revised, compared with the control group. The patient-reported onset of squeaking (46 months postoperatively) was earlier than short-noise emissions (82 months). In the standardised sequence of movements, short-noise always occurred more frequently than squeaking. Small heads (28 mm) were more likely to develop short-noise, while large heads (⩾32 mm) were more likely to develop squeaking. DISCUSSION: Noise evaluation may provide additional value for predicting failure of CoC bearings, though some questions should be better investigated in a dedicated prospective trial.

Long term breeding of the Lmna G609G progeric mouse: Characterization of homozygous and heterozygous models.

The transgenic LmnaG609G progeric mouse represents an outstanding animal model for studying the human Hutchinson-Gilford Progeria Syndrome (HGPS) caused by a mutation in the LMNA gene, coding for the nuclear envelope protein Lamin A/C, and, as an important, more general scope, for studying the complex process governing physiological aging in humans. Here we give a comprehensive description of the peculiarities related to the breeding of LmnaG609G mice over a prolonged period of time, and of many features observed in a large colony for a 2-years period. We describe the breeding and housing conditions underlining the possible interference of the genetic background on the phenotype expression. This information represents a useful tool when planning and interpreting studies on the LmnaG609G mouse model, complementing any specific data already reported in the literature about this model since its production. It is also particularly relevant for the heterozygous mouse, which mirrors the genotype of the human pathology however requires an extended time to manifest symptoms and to be carefully studied.