The mdx mouse model of Duchenne muscular dystrophy (DMD) is used to study disease mechanisms and potential treatments, but its pathology is less severe than DMD patients. Other mouse models were developed to more closely mimic the human disease based on knowledge that upregulation of utrophin has a protective effect in mdx muscle. An mdx:utrophin−/− (dko) mouse was created, which had a severe disease phenotype and a shortened life span. An mdx:utrophin+/− mouse was also created, which had an intermediate disease phenotype compared to the mdx and dko mice. To determine the usefulness of mdx:utrophin+/− mice for long-term DMD studies, limb muscle pathology and function were assessed across the life span of wild-type, mdx, mdx:utrophin+/−, and dko mice. Muscle function assessment, specifically grip duration and rotarod performance, demonstrated that mdx:utrophin+/− mice were weaker for a longer time than mdx mice. Mean myofiber area was smaller in mdx:utrophin+/− mice compared to mdx mice at 12 months. Mdx:utrophin+/− mice had a higher percentage of centrally nucleated myofibers compared to mdx mice at 6 and 12 months. Collagen I and IV density was significantly higher in mdx:utrophin+/− muscle compared to mdx at most ages examined. Generally, mdx:utrophin+/− mice showed an intermediate disease phenotype over a longer time course compared to the mdx and dko mice. While they do not genetically mirror human DMD, mdx:utrophin+/− mice may be a more useful animal model than mdx or dko mice for investigating long-term efficacy of potential treatments when fibrosis or muscle function is the focus.

Increasing time from injury to ACLR was associated with increased incidence of secondary injury seen in the trochlea, lateral femoral condyle, medial tibial plateau, and medial meniscus. Separate analyses of patient age and preinjury activity level showed similar findings, thus supporting the primary analysis.

Aims Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. Patients and Methods A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively. Results The 160 anteroposterior pelvis films revealed that the proposed Area method was statistically different from those described by Widmer and Lewinnek (p < 0.001 and p = 0.004, respectively). They gave the highest inter- and intraobserver reliability (0.992 and 0.998, respectively), and took less time (27.50 seconds (sd 3.19); p < 0.001) to complete. In addition, 21 available CT 3D reconstructions revealed the Area method achieved the highest Pearson’s correlation coefficient (r = 0.956; p < 0.001) and least statistical difference (p = 0.704) from CT with a mean within 1° of CT-3D reconstruction between ranges of 1° to 30° of measured radiological anteversion. Conclusion Our results support the proposed Area method to be the most reliable, accurate, and speedy. They did not support any statistical superiority of the proposed Orthogonal method to that of the Widmer or Lewinnek method. Cite this article: Bone Joint J 2019;101-B:1042–1049.

Background: Solid organ transplant patients are theoretically at increased risk for complications after total joint replacement due to immunosuppressive medication regimens and multiple medical comorbidities. There are a number of studies that report on outcomes of total joint arthroplasty (TJA) following solid organ transplant, however, the results are heterogeneous. This study evaluated the outcomes of TJA in solid organ transplant patients as compared to non-organ transplant controls at one academic medical center. Methods: This study was a single institution retrospective review of a consecutive series of patients who underwent joint replacement following solid organ transplant as compared to a control cohort over a 10year period. Univariable and multivariable generalized linear mixed effects models were used to compare the odds of readmission, infection, mortality, and being discharged home between transplanted (cases) and non-transplanted (control) patients. Results: Transplant and non-transplant cohorts had similar BMI, although transplant patients were younger (61 versus 65 years) and had a higher incidence of Diabetes (55% vs. 16%). On multivariable analysis, there was no difference in the odds of re-admission or rate of infection, but there was an increased risk of death and admission to a rehab facility in the transplant cohort. Conclusion: Overall, this study demonstrates that solid organ transplant alone does not increase the risk of peri-operative complications in patients who underwent hip and knee replacement. However, it should be expected that these patients have a higher mortality rate and that many of them will need to be discharged to a post-acute care facility.