Background: Osteoarthritis is the most common form of arthritis, and is a major cause of disability and chronic pain in adults. However, there is very limited evidence in the scientific literature to support the effectiveness of extracorporeal shockwave therapy (ESWT) in human knee osteoarthritis. This retrospective study aimed to compare the efficacy of ESWT treatment with sham-ESWT on pain, walking speed, physical function, and adverse effects in knee osteoarthritis. Methods: This study will be performed and reported in accordance with the Strengthening the Reporting of Observational studies in Epidemiology checklist. We reviewed patients diagnosed with knee osteoarthritis at our academic center from 2016 to 2017. This retrospective cohort study was approved by the institutional review board in Ruijin Hospital. The primary outcome measure was pain on movement measured by a 100-cm visual analog scale. The secondary outcome measures included the Western Ontario and McMaster University Osteoarthritis Index, range of motion, and adverse effects. Statistical analysis was performed using Statistical Package for Social Sciences version 20.0 (IBM Corporation, Armonk, NY). A P -value of <.05 was defined as statistical significance. Results: The hypothesis was that ESWT would be an effective treatment for improving pain and physical function in knee osteoarthritis to control symptoms. Trial registration: This study protocol was registered in Research Registry (researchregistry5801).

Purpura fulminans (PF) is a rare syndrome characterized by microvasculature coagulation and thrombosis with hemorrhagic necrosis that can lead to purpuric lesions, skin necrosis and gangrene and autoamputation of distal extremities [1]. It has been reported as a complication to scarlet fever and meningococcal infections in infants and young children and is associated with acquired or congenital Protein C and S deficiencies [2,3]. Although less common, PF has also been reported as an idiopathic disease in adults with protein S deficiency and also as an acute infectious form in patients with sepsis and disseminated intravascular coagulation (DIC) [4]. We report a case of a 49-year-old female with ulcerative colitis who developed PF with limb ischemia and gangrene as a complication to transverse colon perforation and sepsis and discuss treatment strategies that are likely to improve the outcome. Case report A 49-year-old previously healthy female presented with hematochezia and underwent a colonoscopy with diagnostic findings of ulcerative colitis. She was discharged to her home with prednisone taper for four weeks. The following week she presented with a transverse colon perforation, requiring subtotal colectomy, abdominal washout and ileostomy. Her postoperative course was complicated by polymicrobial intra-abdominal infection causing septic shock. Treatment with broad-spectrum antibiotics were initiated immediately and hemodynamic support with fluids and vasopressors was provided. On postoperative day 3, patient developed non-blanching, angulated, purpuric smooth skin patches, and thin plaques with areas of hemorrhagic bullae over her distal extremities,