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Endoprosthetic reconstructions of the hip and knee are currently reimbursed as primary hip and knee arthroplasty according to Current Procedural Terminology ( CPT ) coding guidelines. The purpose of this study was to compare hospital resources consumed by patients undergoing endoprosthetic reconstruction with those consumed by patients undergoing primary arthroplasty. The authors' hypothesis was that the former group carries more comorbidities, experiences longer length of stay (LOS), and has greater resource consumption. A retrospective review was performed of 61 patients undergoing endoprosthetic reconstruction and 745 patients undergoing primary hip or knee arthroplasty between 2015 and 2018 at a single institution. Demographic, clinical, and financial data were compared. The Charlson Comorbidity Index (CCI) was used to measure patients' health status and identify comorbidities associated with prolonged LOS through linear regression analysis. Patients who underwent endoprosthetic reconstruction had a greater than 3.5 times average LOS compared with primary arthroplasty patients: 10.81 days vs 2.94 days ( P P Orthopedics . 2021;44(1):e73–e79.]

Backside damage of the polyethylene in TKA is a potential source of debris. The location of the tibial post in posterior-stabilized implants may influence micromotion, and thus affect backside damage, as may surface roughness.We used implant retrieval analysis to (1) examine if there were differences in backside damage among three modern posterior-stabilized implants attributable to variable surface roughness; (2) determine if the location of damage on the tibial post affected the pattern of backside damage; and (3) determine if demographics influenced backside damage.We identified 403 posterior-stabilized tibial retrieved inserts (147 NexGen(®), 152 Optetrak(®), 104 Genesis(®) II). The damage on the surfaces of the tibial posts was previously graded. The backside of the inserts (divided into quadrants) were scored for evidence of damage. The total quadrant damage was compared for each implant group, the relationship between post face damage and location of damage on the backside was determined for each implant group, and total backside damage was compared among the three implant groups.No correlation was found between the location of damage on the post and location of damage on the backside of the implant for any of the three groups. The Genesis(®) II polyethylene implants, which articulate with a highly polished tibial tray, showed a significantly lower total backside damage score (p0.01) when compared with the other two implant groups. The Genesis(®) II and Optetrak(®) showed significantly more damage in the posterior quadrants of the implants (p0.01) when compared with the anterior quadrants. A linear regression analysis revealed that lower tibial tray surface roughness was correlated with decreased damage.An implant design with a highly polished tibial tray was associated with decreased backside damage. However, tibial post design and location did not influence the location of backside damage.Our study showed that a highly polished tibial tray was associated with decreased damage to the backside of polyethylene inserts independent of post design and location. These findings should be taken into consideration when new generations of implants are designed.

The genus Dermocystidium comprises fungal pathogens of the order Dermocystida in the class Ichthyosporea (http://www.ncbi.nlm.nih.gov/taxonomy). Several different Dermocystidium species have been described, infecting a variety of fish hosts and producing gill infections, skin lesions and visceral disease all over the world (Wildgoose 1995; Pekkarinen & Lotman 2003; Pekkarinen et al. 2003; Feist et al. 2004; Zhang & Wang 2005). To our knowledge, there are two reports on Dermocystidium infections in cardinal tetra, Paracheirodon axelrodi and neon tetra, Paracheirodon innesi (Reichenbach-Klinke 1982; Lewisch 2010). However, these reports did neither include histological and ultrastructural examinations nor molecular genetic investigations to confirm the diagnosis and identify the aetiologic species. In January 2013, increased mortalities of cardinal tetra, P. axelrodi of a 350-L aquarium were reported, occurring after purchase of additional fish. During the clinical examination, most of the fish were swimming in normal active condition, but some were lethargic or displayed a transparent mass on the skin of the head or body. The masses were up to 5 mm in diameter and contained a central, white tubular structure. Similar masses were located on the fins of some fish, but were considerably smaller in these locations. A parasitic infestation of the skin of these fish was excluded via microscopic examination, and normal results were obtained after analysis of the water values and inspection of the pump and filter system. Six cardinal tetra, P. axelrodi and two firehead tetra, Hemigrammus bleheri were submitted for pathological examination in formalin and for molecular genetic examination in ethanol. Only two cardinal tetra displayed skin lesions. Before embedding, one tetra was post-fixed in Davidson’s fixative and sections of glycolmethacrylate/methylmethacrylate-embedded samples were routinely processed for histological examination and stained with haematoxylin and eosin (HE), Giemsa, silver impregnation and periodic acid Schiff (PAS) reaction according to standard protocols. Samples of the mass were also routinely processed for transmission and scanning electron microscopy on a transmission electron microscope (Zeiss EM 10) or on a digital scanning electron microscope (Zeiss DSM 950), respectively. The macroscopic examination of the cardinal tetra revealed a focally extensive, bulging, hemispherical, transparent oedema (4 mm in diameter) of the ventral skin on the head. Central, within Correspondence M C Langenmayer, Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterin€ arstrasse 13, 80539 Munich, Germany (e-mail: langenmayer@patho.vetmed.uni-muenchen.de) Langenmayer and Lewisch contributed equally to this work.

The current study adapted the Garner paradigm for diagnosing separable versus integral perceptual dimensions to the eye-blink classical conditioning paradigm using rabbits. Specifically, this study examined the ability of rabbits to categorize stimuli based on one auditory dimension while ignoring a second, irrelevant dimension by displaying an appropriate eye-blink for bilaterally conditioned discriminative responses. Tones used in training varied along two dimensions, starting frequency and magnitude of frequency sweep upwards from the start. Rabbits first learned to categorize along a single dimension (blinking one eye for one category response and the other eye for the other response) and then continued to categorize tones in a second phase in which the irrelevant dimension was varied. The variation of the irrelevant dimension did not disrupt performance, indicating that rabbits perceive these dimensions as separable.