Journal of orthopaedic research : official publication of the Orthopaedic Research Society
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To elucidate the pathophysiological mechanisms underlying chronic nerve-stretch injury, we gradually lengthened rat femurs by 15 mm at the rate of 0.5 mm/day (group L, n = 13). The control groups comprised sham-operated (group S, n = 10) and naive (group N, n = 8) rats. Immediately after the lengthening, we performed a conduction study on their sciatic nerves and harvested samples. ⋯ The immunohistochemical alteration of Nav1.8 protein expression was parallel to the results of the mRNA expression. Previous studies involving neuropathic states have suggested that pain/paresthesia is modulated by a subset of sodium channels, including downregulation and/or upregulation of TTX-R and TTX-S sodium channels, respectively. Our findings indicate that Nav1.8 downregulation may be one of the pathophysiological mechanisms involved in limb lengthening-induced neuropathy.
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Bacterial remnants and subclinical biofilms residing on prosthesis surfaces have been speculated to play a role in hip implant loosening by opsonizing otherwise relatively inert wear particles. The innate immune system recognizes these microbial pathogen-associated molecular patterns (PAMPs) using Toll-like receptors (TLRs). Our objective was to evaluate the possible presence of TLRs in aseptic synovial membrane-like interface tissue. ⋯ Thus aseptic periprosthetic tissue seems to be very reactive to PAMPs. It has been recently recognized that TLR do not only respond to traditional PAMPs, but also to endogenous alarmings or danger signals released from necrotic and activated cells. Alarming-TLR interaction in the periprosthetic tissue might be a novel mechanism of aseptic loosening of endoprosthesis.
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Controlled Clinical Trial
Effects of platelet-rich plasma on the quality of repair of mechanically induced core lesions in equine superficial digital flexor tendons: A placebo-controlled experimental study.
Tendon injuries are notorious for their slow and functionally inferior healing. Intratendinous application of platelet-rich plasma (PRP) has been reported to stimulate the repair process of tendon injuries, but there is little conclusive evidence for its effectiveness. A placebo-controlled experimental trial was performed to test the hypothesis that a single intratendinous PRP treatment enhances the quality of tendon repair, as evidenced by improved biochemical, biomechanical, and histological tissue properties. ⋯ The repair tissue in the PRP group showed a higher strength at failure (p = 0.021) and Elastic Modulus (p = 0.019). Histologically, PRP-treated tendons featured better organization of the collagen network (p = 0.031) and signs of increased metabolic activity (p = 0.031). It was concluded that PRP increases metabolic activity and seems to advance maturation of repair tissue over nontreated experimentally induced tendon lesions, which suggests that PRP might be beneficial in the treatment of clinical tendon injuries.
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Healing at the osteotendinous junction (OTJ) is challenging in orthopedic surgery. The present study aimed to test extracorporeal shockwave (ESW) in treatment of a delayed OTJ healing. Twenty-eight rabbits were used for establishing a delayed healing (DH) model at patella-patellar-tendon (PPT) complex after partial patellectomy for 4 weeks and then were divided into DH and ESW groups. ⋯ The accelerated osteogenesis could be explained by acceleration of endochondral ossification. In conclusion, ESW was able to induce osteogenesis at OTJ with delayed healing with enhanced endochondral ossification process and regeneration of fibrocartilage zone. These findings formed a scientific basis to potential clinical application of ESW for treatment of delayed OTJ healing.
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The objective of this article was to investigate the safety and regenerative potential of a newly developed biomimetic scaffold when applied to osteochondral defects in an animal model. A new multilayer gradient nano-composite scaffold was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. In the femoral condyles of 12 sheep, 24 osteochondral lesions were created. ⋯ Quantitative macroscopic and histological score evaluations confirmed the qualitative trends observed. The results of the present study showed that this novel osteochondral scaffold is safe and easy to use, and may represent a suitable matrix to direct and coordinate the process of bone and hyaline-like cartilage regeneration. The comparable regeneration process observed with or without autologous chondrocytes suggests that the main mode of action of the scaffold is based on the recruitment of local cells.