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La anquilosis de la articulación temporomandibular (ATM) corresponde a un trastorno temporomandibular clasificado dentro de la hipomovilidad mandibular crónica. La literatura define anquilosis como una inmovilidad anormal de la mandíbula, desorden que lleva a una restricción de la apertura bucal con reducción parcial de los movimientos mandibulares o una completa inmovilidad de la mandíbula. El objetivo del presente artículo es realizar una revisión en cuanto a la clasificación, epidemiología, etiopatogenia, diagnóstico y tratamiento de la anquilosis de la articulación temporomandibular. Palabras clave: Articulación temporomandibular, trastornos temporomandibulares, anquilosis temporomandibular. SUMMARY Ankylosis of the temporomandibular joint (TMJ) corresponds to a temporomandibular disorder classified into chronic mandibular hypomobility. Ankylosis defines literature as an abnormal jaw immobility disorder that leads to a restriction of mouth opening with partial reduction of mandibular movement or complete immobility of the jaw. The aim of this article is to review the classification, epidemiology, etiology, diagnosis and treatment of temporomandibular joint ankylosis.

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Aseptic loosening is the main reason for revision of total hip arthroplasty, and relative micromotions between cementless acetabular cups and bone play an important role regarding their comparatively high loosening rate. Therefore, the aim of the present study was to analyze the influence of resulting frictional torques on the primary stability of press-fit acetabular cups subjected to two different bearing partners. A cementless press-fit cup was implanted in bone-like foam. Primary stability of the cup was analyzed by determining spatial total, translational, and rotational interface micromotions by means of an eddy current sensor measuring system. Torque transmission into the cup was realized by three synchronous servomotors considering resultant friction torques based on constant friction for ceramic-on-ceramic (CoC: μ = 0.044; max. resultant torque: 1.5 Nm) and for ceramic-on-polyethylene (CoP: μ = 0.063; max. resultant torque: 1.9 Nm) bearing partners. Rotational micromotion of CoC was 8.99 ± 0.85 µm and of CoP 13.39 ± 1.43 µm. Translational micromotion of CoC was 29.93 ± 1.44 μm and of CoP 39.91 ± 2.25 μm. Maximum total relative micromotions were 37.10 ± 1.07 μm for CoC and 51.64 ± 2.18 μm for CoP. Micromotions resulting from CoC were statistically lower than those resulting from CoP (p < 0.05). The described 3D-measuring set-up offers a novel in vitro method of measuring primary stability of acetabular cups. We can therefore conclude, that primary stability of acetabular cup systems can be observed using either the lower friction curve (CoC) or the higher friction curve (CoP). In future studies different cup designs or cup fixation mechanisms may be tested and compared in vitro and assessed prior to implantation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2745-2753, 2018.

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Introduction Cementless straight stems show very good survival rates. However, the more distal force application of straight stems may lead to release-related proximal stress-shielding. Nevertheless, this technical brief had the objective of conducting a biomechanical in vitro analysis comparing short stems with established straight stems with respect to their primary torsional stability. Methods Two cementless short hip stems and three cementless straight hip stems were implanted in n=5 synthetic femora each. Torsional torques were applied into the hip stems at a continuous interval of ±7Nm. Micromotions were measured by six inductive extensometers on four different measurement levels. Results At the proximal measuring point, significantly smaller relative micromotions of the CLS® prosthesis could be detected compared to all other stem models (p&lt;0.05). In all stem models, smallest relative micromotions were found at the metaphyseal/diaphyseal measuring point. Only at the measuring point of the distal tips of the straight stems, statistically significantly lower relative micromotion of the CLS® stem compared to the Trendhip® stem could be found (p&lt;0.01). Conclusions All the investigated stems generally display a rather comparable anchoring pattern and an almost physiological force application. Since the comparatively long straight stems present an anchoring pattern nearly identical to that of the examined short stems, a shortening of the established straight stems could be taken into consideration. This would offer the advantage of minimally invasive surgery and bone-saving resection as well as preservation of cancellous bone in case a revision would become necessary.