[Faecolithiasis: straightforward to detect, but often missed]. / Fecolithiase: goed te herkennen, maar vaak gemist.

Faecal impaction is a problem which is becoming more prevalent now that the number of elderly patients is increasing. When not detected and treated inadequately, it can lead to symptoms such as diarrhoea, faecal incontinence and other serious problems like anorexia, vomiting and rectal ulcers with bleeding or even a bowel perforation. We describe two patients with serious and less common complications of faecolithiasis. Patient A, a 79-year-old woman with signs of dementia, presented with faecal incontinence and unexplained worsening of her cognitive symptoms leading to a situation where she could no longer live in her own home. Patient B, a 52-year-old woman, presented with urinary retention, stomach ache and constipation, suggesting an obstructive tumour in the pelvis. In both patients a CT-scan showed no pathology. Neither of the patients responded to oral laxative treatment. Eventually, a faecolith was detected and treated through endoscopic inspection and fragmentation. Both patients recovered completely.

Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo.

Phase transformation, roughness, and microhardness of artificially aged yttria- and magnesia-stabilized zirconia femoral heads.

Yttria-stabilized zirconia ceramic (Y-TZP) has been used in total hip arthroplasty for many years but is susceptible to low-temperature aging. Medical-grade magnesia-stabilized zirconia (Mg-PSZ) is less commonly used; however, it has been shown to resist phase transformation. The purpose of this study was to directly compare the effects of artificial aging on phase transformation, surface roughness, and Vickers microhardness on Y-TZP and Mg-PSZ femoral heads. Y-TZP and Mg-PSZ heads were artificially aged in an autoclave in stages up to a total of 49 h. The surface roughness of Y-TZP significantly increased with each stage of artificial aging. Y-TZP heads aged for 49 h had a significantly higher monoclinic phase concentration and roughness, and a significantly lower microhardness, than nonaged Y-TZP heads. Artificial aging also caused the surface of Y-TZP to exhibit a lumpy "orange peel"-like appearance with a significantly higher mean peak height, suggesting that artificial aging causes individual grains to be pushed out of the surface. In contrast, artificial aging did not significantly affect the properties of Mg-PSZ heads. These findings suggest that Mg-PSZ is a satisfactory material for orthopaedic implant use, while Y-TZP, in the form tested, is not adequately stable for use as a bearing surface.