The mass mortality suffered by the sea urchin Diadema antillarum between 1983-1984 is considered one of the major causes of coral reef degradation in the Caribbean. Its near disappearance resulted in a disproportionate growth of macroalgae that has led to a 'phase shift' from coral-to-algal dominated reefs. The close relationship between this echinoid and the functioning of coral reef ecosystems makes it imperative to better understand the potential for recovery of its populations. From 2009 to 2011, we assessed the density and size structure of D. antillarum in various reefs where previous population data were available. Results indicate a modest increase in density in all localities with respect to the last time they were surveyed in 2003/2004. Nevertheless, density values are still lower than values reported for the island prior to the die-off. Overall density did not surpass 1.49 ind. per m 22 , and did not change considerably during the studied period. Lack of population growth coincided with a lack of juveniles; suggesting that population growth at the studied sites may be limited by the number of individuals recruiting into the juvenile stage.

We present a case report of a patient with severe valgus deformity of the right knee due to multiple hereditary exostoses (MHEs) treated with total knee arthroplasty (TKA). The surgical management of MHE affecting the knee encompasses exostoses resection, joint deformity rectification, and limb-length discrepancy alignment. On rare occasions, distraction osteogenesis and TKA have been used to correct valgus deformities of the knee. TKA in MHE patients with knee involvement has only been described in 6 cases. Several considerations, such as extensive knowledge of frequently occurring skeletal aberrations, are required to successfully correct the deformities associated with MHE via TKA. This report describes a case of severe valgus knee deformity with a rotational component in MHE managed with TKA, the surgical technique, and future recommendations.

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