We describe the bony and cartilaginous structures of five fetal skulls of Stenella attenuata (pantropical spotted dolphin) specimens. The specimens represent early fetal life as suggested by the presence of rostral tactile hairs and the beginnings of skin pigmentation. These specimens exhibit the developmental order of ossification of the intramembranous and endochondral elements of the cranium as well as the functional and morphological development of specific cetacean anatomical adaptations. Detailed observations are presented on telescoping, nasal anatomy, and middle ear anatomy. The development of the middle ear ossicles, ectotympanic bone, and median nasal cartilage is of interest because in the adult these structures are morphologically different from those in land mammals. We follow specific cetacean morphological characteristics through fetal development to provide insight into the form and function of the cetacean body plan. Combining these data with fossil evidence, it is possible to overlie ontogenetic patterns and discern evolutionary patterns of the cetacean skull. Anat Rec, 294:1743Rec, 294: -1756Rec, 294: , 2011. V V C 2011 Wiley-Liss, Inc.Key words: cranial development; Stenella attenuata; telescoping; middle ear; CetaceaThe development of the Cetacea skull was studied in embryos (de Burlet, 1913a(de Burlet, , 1913b(de Burlet, , 1914a(de Burlet, , 1914bSchreiber, 1916;Honigmann, 1917;Rauschmann et al., 2006;Thewissen and Heyning, 2007) and fetuses (Schulte, 1916;Ridewood, 1923;Eales, 1950). Cetacean research focused on specific biological systems to understand differences within Mammalia. Comtesse-Weidner (2007), Miller (1923 and Kellogg (1928aKellogg ( , 1928b) studied morphological elements including telescoping. Oelschl-ä ger and Buhl (1985), Klima and van Bree (1990), and Klima (1995 studied nasal anatomy and development. Oelschlä ger (1986, 1990), Solntseva (1990, 2002), and Kinkel et al. (2001 concentrated on hearing reception and sound emission while Mead and Fordyce (2009) focused on general skull anatomy. Although comparative embryological studies on cetaceans were rare, developmental studies were mostly nonexistent. Such studies (e.g., Thewissen et al., 2006, Armfield et al., in press) allow for a deeper understanding of the ontogenetic constraints on the evolution of the cetacean body plan.Habitat changes alter adaptations for specific cetacean body plans. These modifications include those of anatomical function and body plan from land mammals to fully aquatic, air breathing marine mammals. Our study focuses on anatomical structures of five Stenella attenuata (pantropical spotted dolphin) fetuses. Here we describe bony and cartilaginous structures of the

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the intestinal tract and is associated with decreased bone mineral density. IBD patients are at higher risk of osteopenia, osteoporosis and fracture compared to non-IBD patients. The impact of IBD on the performance of orthopedic implants has not been well studied. We hypothesized that a history of IBD at the time of primary total hip arthroplasty (THA) would increase the risk of subsequent failure as assessed by revision surgery. A retrospective implant survival analysis was completed using the Swedish Hip Arthroplasty Registry and the Sweden National Patient Register. A total of 150,073 patients undergoing THA for osteoarthritis within an 18-year period were included in the study. THA patients with (n = 2,604) and without (n = 147,469) a history of IBD at the time of THA were compared with primary revision as the main endpoint and adjusted using sex, age category and comorbidity (Elixhauser scores) as covariates. We found that patients with a history of IBD had a relatively higher risk of revision surgery for septic causes while the non-IBD patients had a relatively higher risk of revision for aseptic causes (p = 0.004). Our findings suggest there may be an association between gut health and THA performance.

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Articular cartilage lines the load-bearing surfaces of long bones and undergoes compositional and structural degeneration during osteoarthritis progression. Contrast enhanced microcomputed tomography (μCT) is being applied to a variety of preclinical models, including the mouse, to map structural and compositional properties in 3-D. The thinness (~30–50 μm) and high cellularity of mouse articular cartilage presents a significant imaging challenge. Our group previously showed that mouse articular cartilage and proteoglycan (PG) content can be assessed by μCT with the ioxagalate-based contrast agent Hexabrix, but the voxel size used (6 μm) was deemed to be barely adequate. The objective of the present study is to assess the utility of a novel contrast agent, CA4+, to quantify mouse articular cartilage morphology and composition with high resolution μCT imaging (3 μm voxels) and to compare the sensitivity of CA4+ and Hexabrix to detect between-group differences. While both contrast agents are iodine-based, Hexabrix is anionic and CA4+ is cationic so they interact differently with negatively charged PGs. With CA4+, a strong correlation was found between non-calcified articular cartilage thickness measurements made with histology and μCT (R2 = 0.72, p < 0.001). Cartilage degeneration – as assessed by loss in volume, thickness and PG content – was observed in 34-week old mice when compared to both 7- and 12-week old mice. High measurement precision was observed with CA4+, with the coefficient of variation after repositioning and re-imaging samples equaling 2.8%, 4.5%, 7.4% and 5.9% for attenuation, thickness, volume, and PG content, respectively. Use of CA4+ allowed increased sensitivity for assessing PG content compared to Hexabrix, but had no advantage for measurement of cartilage thickness or volume. This improvement in imaging should prove useful in preclinical studies of cartilage degeneration and regeneration.

We completed a systematic literature review of in vivo animal models that use arthrotomy-based methods to study particle-induced peri-implant osteolysis. The purpose of the review was to characterize the models developed to date, to determine the questions addressed, to assess scientific rigor and transparency and to identify gaps in knowledge. We probed three literature databases (Medline, Embase and Scopus) and found 77 manuscripts that fit the search parameters. In the most recent 10 years, researchers mainly used rat and mouse models, whereas in the previous 20 years large animal, canine and rabbit models were more common. The studies have demonstrated several pathophysiology pathways, including macrophage migration, particle phagocytosis, increased local production of cytokines and lysosomal enzymes, elevated bone resorption and suppressed bone formation. The effect of variation in particle characteristics and concentration received limited attention with somewhat mixed findings. Particle contamination by endotoxin was shown to exacerbate peri-implant osteolysis. The possibility of early diagnosis was demonstrated through imaging and biomarker approaches. Several studies showed that both local and systemic delivery of bisphosphonates inhibits the development of particle-induced osteolysis. Other methods of inhibiting osteolysis include the use of anabolic agents and altering the implant design. Few studies examined non-surgical rescue of loosened implants, with conflicting results with alendronate. We found that the manuscripts often lacked the methodological detail now advocated by the ARRIVE guidelines, suggesting that improvement in reporting would be useful to maximize rigor and transparency.

Numerous procedures have been described for the surgical treatment of symptomatic bunionettes. We describe the technique, results, and follow-up of patients treated with a chevron osteotomy of the distal fifth metatarsal. This surgical approach to the treatment of bunionette is presented as a viable alternative to other surgical procedures. Sixteen distal fifth metatarsal chevron osteotomies were performed on 12 patients. Follow-up was from 15 months to 6 years, with an average follow-up of 3.2 years. A 100-point scoring system was devised and the average score improved from 44 points before surgery (range 20-65) to 91 points after surgery (range 65-100). There was one complication of a transfer metatarsalgia. The overall results were good to excellent, except for the transfer metatarsalgia, which was rated as fair. We have used the procedure in a laterally deviated, plantar metatarsal. There is concern that alternatives be used in a laterally deviated, plantarflexed fifth metatarsal. We have continued to use the chevron osteotomy with this condition.

In this paper, we provide a detailed protocol for a model of long bone mechanical marrow ablation in the rodent, including surgical procedure, anesthesia, and pre-and post-operative care. In addition, frequently used experimental end points are briefly discussed. This model was developed to study intramembranous bone regeneration following surgical disruption of the marrow contents of long bones. In this model, the timing of the appearance of bone formation and remodeling is well-characterized and therefore the model is well-suited to evaluate the in vivo effects of various agents which influence these processes. When biomaterials such as tissue engineering scaffolds or metal implants are placed in the medullary cavity after marrow ablation, end points relevant to tissue engineering and implant fixation can also be analyzed. By sharing a detailed protocol, we hope to improve inter-laboratory reproducibility.

Biomarkers are of interest to identify patients at risk for peri‐implant osteolysis and aseptic loosening. We used a rat model of particle‐induced peri‐implant osteolysis to investigate if early changes in biomarkers were associated with subsequent implant fixation strength. Implants were placed in rat femora, which were then challenged with intra‐articular knee injections of either clean polyethylene, lipopolysaccharide‐doped polyethylene, or cobalt‐chromium alloy particles, with particle‐free vehicle serving as control (n ≥ 8 per group). Rats were weighed weekly, blood was collected at weeks 0, 3, 5, and 6, and locomotor behavior was assessed 4 days before study conclusion. Rats were euthanized 6 weeks post surgery. Week 6 serum was analyzed for five bone remodeling markers, while longitudinal serum was assessed for osteocalcin. Bone‐implant contact, peri‐implant trabecular architecture, and implant fixation strength were measured. Rats challenged with cobalt‐chromium particles had a significant reduction in implant fixation strength compared with the vehicle‐control group (P = .034). This group also had elevated serum osteocalcin (P = .005), depressed weight gain (P = .001) and less frequent rearing behavior (P = .029). Regardless of group, change in serum osteocalcin at week 3 (r = −.368; P = .046), change in weight at week 2 (r = .586; P < .001), as well as weight change at all other time intervals were associated with fixation strength. The finding that early alterations in serum osteocalcin and body weight were predictive of subsequent implant fixation strength supports continued investigation of biomarkers for early detection of peri‐implant osteolysis and implant loosening. Further, change in biomarker levels was found to be more indicative of implant fixation status than any single measurement.