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Background: Adequate irrigation of open musculoskeletal injuries is considered the standard of care to decrease bacterial load and other contaminants. While the benefit of debris removal compared with the risk of further seeding by high-pressure lavage has been studied, the effects of irrigation on muscle have been infrequently reported. Our aim in the present study was to assess relative damage to muscle by pulsatile lavage compared with bulb-syringe irrigation. Methods: In an animal model of heterotopic ossification, 24 Sprague-Dawley rats underwent hindlimb blast amputation via detonation of a submerged explosive, with subsequent through-the-knee surgical amputation proximal to the zone of injury. All wounds were irrigated and underwent primary closure. In 12 of the animals, pulsatile lavage (20 psi [138 kPa]) was used as the irrigation method, and in the other 12 animals, bulb-syringe irrigation was performed. A third group of 6 rats did not undergo the blast procedure but instead underwent surgical incision into the left thigh muscle followed by pulsatile lavage. Serial radiographs of the animals were made to monitor the formation of soft-tissue radiopaque lesions until euthanasia at 6 months. Image-guided muscle biopsies were performed at 8 weeks and 6 months (at euthanasia) on representative animals from each group. Histological analysis was performed with hematoxylin and eosin, alizarin red, and von Kossa staining on interval biopsy and postmortem specimens. Results: All animals managed with pulsatile lavage, with or without blast injury, developed soft-tissue radiopaque lesions, whereas no animal that had bulb-syringe irrigation developed these lesions (p = 0.001). Five of the 12 animals that underwent blast amputation with pulsatile lavage experienced wound complications, whereas no animal in the other 2 groups experienced wound complications (p = 0.014). Radiopaque lesions appeared approximately 10 days postoperatively, increased in density until approximately 16 weeks, then demonstrated signs of variable regression. Histological analysis of interval biopsy and postmortem specimens demonstrated tissue damage with inflammatory cells, cell death, and dystrophic calcification. Conclusions: Pulsatile lavage of musculoskeletal wounds can cause irreversible insult to tissue, resulting in myonecrosis and dystrophic calcification. Clinical Relevance: The benefits and offsetting harm of pulsatile lavage (20 psi) should be considered before its routine use in the management of musculoskeletal wounds.

Five patients with Darier's disease and 6 patients with pityriasis rubra pilaris were treated with 13-cis-retinoic acid. Extracts of separated epidermis were assayed for extractable protein, lactic dehydrogenase, Cathepsin D, beta glucuronidase and neutral proteinase before beginning therapy and 2, 4 and 8 weeks after therapy had begun. The epidermal extracts from patients with pityriasis rubra pilaris before beginning therapy were similar to extracts from normal control patients. During the course of therapy with 13-cis-retinoic acid, protein extractability, lactic dehydrogenase and neutral proteinase did not change; there was a highly significant decrease in the specific activity of the lysosomal hydrolases Cathepsin D and beta glucuronidase. A similar but less dramatic fall was noted in the Darier's patients taking 13-cis-retinoic acid. Darier's patients also had a decrease in neutral proteinase activity before beginning therapy; the specific activity of this enzyme increased during the course of therapy. 13-cis-retinoic acid does not induce clinical remission by increasing the intracellular concentration of lysosomal enzymes in epidermis in vivo.

Background Although use of nonsteroidal antiinflammatory drugs and low-dose irradiation has demonstrated efficacy in preventing heterotopic ossification (HO) after THA and surgical treatment of acetabular fractures, these modalities have not been assessed after traumatic blast amputations where HO is a common complication that can arise in the residual limb. Questions/purposes The purpose of this study was to investigate the effectiveness of indomethacin and irradiation in preventing HO induced by high-energy blast trauma in a rat model. Methods Thirty-six Sprague-Dawley rats underwent hind limb blast amputation with a submerged explosive under water followed by irrigation and primary wound closure. One group (n = 12) received oral indomethacin for 10 days starting on postoperative Day 1. Another group (n = 12) received a single dose of 8 Gy irradiation to the residual limb on postoperative Day 3. A control group (n = 12) did not receive either. Wound healing and clinical course were monitored in all animals until euthanasia at 24 weeks. Serial radiographs were taken immediately postoperatively, at 10 days, and every 4 weeks thereafter to monitor the time course of ectopic bone formation until euthanasia. Five independent graders evaluated the 24week radiographs to quantitatively assess severity and qualitatively assess the pattern of HO using a modified This work was funded by the Department of Defense Peer Reviewed Orthopaedic Research Program (VDP, Principal Investigator; Award Number: W81XWH-10-1-0975). Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA-approval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the animal protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.