A rare case of pigmented villonodular synovitis after unicompartmental knee replacement: a case report

Pigmented villonodular synovitis is a benign proliferative disease involving the synovium. Pigmented villonodular synovitis is rare after replacement arthroplasty and has not been recognised and reported as a cause of failure of unicompartmental knee replacement in the literature

Characterization of a rat osteotomy model with impaired healing

<p>Abstract</p> <p>Background</p> <p>Delayed union or nonunion are frequent and feared complications in fracture treatment. Animal models of impaired bone healing are rare. Moreover, specific descriptions are limited although understanding of the biological course of pathogenesis of fracture nonunion is essential for therapeutic approaches.</p> <p>Methods</p> <p>A rat tibial osteotomy model with subsequent intramedullary stabilization was performed. The healing progress of the osteotomy model was compared to a previously described closed fracture model. Histological analyses, biomechanical testing and radiological screening were undertaken during the observation period of 84 days (d) to verify the status of the healing process. In this context, particular attention was paid to a comparison of bone slices by histological and immunohistological (IHC) methods at early points in time, <it>i.e</it>. at 5 and 10 d post bone defect.</p> <p>Results</p> <p>In contrast to the closed fracture technique osteotomy led to delayed union or nonunion until 84 d post intervention. The dimensions of whole reactive callus and the amounts of vessels in defined regions of the callus differed significantly between osteotomized and fractured animals at 10 d post surgery. A lower fraction of newly formed bone and cartilaginous tissue was obvious during this period in osteotomized animals and more inflammatory cells were observed in the callus. Newly formed bone tissue accumulated slowly on the anterior tibial side with both techniques. New formation of reparative cartilage was obviously inhibited on the anterior side, the surgical approach side, in osteotomized animals only.</p> <p>Conclusion</p> <p>Tibial osteotomy with intramedullary stabilisation in rats leads to pronounced delayed union and nonunion until 84 d post intervention. The early onset of this delay can already be detected histologically within 10 d post surgery. Moreover, the osteotomy technique is associated with cellular and vascular signs of persistent inflammation within the first 10 d after bone defect and may be a contributory factor to impaired healing. The model would be excellent to test agents to promote fracture healing.</p

Prioritizing Rare Diseases: Psychological Effects Influencing Medical Decision Making

Background. Measuring societal preferences for rarity has been proposed to determine whether paying pre- mium prices for orphan drugs is acceptable. Objective. To investigate societal preferences for rarity and how psychological factors affect such preferences. Method. A postal survey containing resource allocation dilemmas involving patients with a rare disease and patients with a common disease, equal in severity, was sent out to a randomly selected sample of the population in Sweden (return rate 42.3%, n = 1270). Results. Overall, we found no evidence of a general preference for prioritizing treat- ment of patients with rare disease patients over those with common diseases. When treatment costs were equal, most respondents (42.7%) were indifferent between the choice options. Preferences for prioritizing patients with common diseases over those with rare diseases were more frequently displayed (33.3% v. 23.9%). This tendency was, as expected, amplified when the rare disease was costlier to treat. The share of respondents choosing to treat patients with rare diseases increased when present- ing the patients in need of treatment in relative rather than absolute terms (proportion dominance). Surprisingly, identifiability did not increase preferences for rarity. Instead, identifying the patient with a rare disease made respondents more willing to prioritize the patients with common diseases. Respondents’ levels of education were significantly associated with choice—the lower the level of education, the more likely they were to choose the rare option. Conclusions. We find no support for the existence of a general preference for rarity when setting health care priorities. Psychological effects, especially proportion dominance, are likely to play an important role when pre- ferences for rarity are expressed.  Funding agencies: Swedish Association of the Pharmaceutical Industry (LIF); Ragnar Soderberg Foundation</p