Computational modelling of mobile bearing TKA anterior-posterior dislocation.

Anterior-posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert's articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445 N vs. 412 N). The unconstrained insert dislocated by means of spin-out whereas in the constrained TKA the femur dislocated from the bearing during posterior drawer and the bearing from the baseplate during anterior drawer. MCL function is an important consideration during ligament balancing since a ± 10% variation in MCL tension affects dislocation forces by ± 20%. The simulation platform provided the means to investigate TKA designs in terms of anterior-posterior stability as a function of knee flexion, collateral ligament function and mechanical morphology.

1-(2-Methyl-benzo-yl)-3-m-tolyl-thio-urea.

The molecule of the title compound, C(16)H(16)N(2)OS, is not planar; the two aromatic rings are inclined to one another by 37.59 (9)°. There are intra-molecular hydrogen bonds between the benzoyl O atom and the H atom of the thio-amide N atom, and between the thio-urea S atom and the H atom of the tolyl group. These hydrogen bonds stabilize the mol-ecule in such a way that the thio-urea group adopts a trans-cis geometry. In the crystal structure, mol-ecules are linked by N-H⋯S inter-molecular hydrogen bonds, forming centrosymmetric dimers.

Primary linitis plastica of the rectosigmoid in a thirteen year old boy.

Childhood malignant neoplasms of the gut are extremely rare. The reported incidence of colorectal cancers in patients under 20 years of age is 1 in 10 million. The low index of suspicion for this tumour in children results in advanced disease at diagnosis and subsequently a poor prognosis. A rare case of a primary linitis plastica of the rectum occurring in a 13 year old boy is reported with review of pertinent literature.

Hypovitaminosis E induced neuropathy in exocrine pancreatic failure.

A 4 year old girl with congenital nerve deafness and pancreatic insufficiency had incapacitating ataxia. Electrophysiological studies of the median nerve and the brain stem evoked response were abnormal. Serum vitamin E concentration was low. After intramuscular injections of vitamin E the ataxia disappeared and electrophysiological variables reverted to normal.