Free radicals, such as reactive oxygen species (ROS) which are released abruptly after deflation of an ischaemic tourniquet, cause reperfusion injuries. Ischaemic precondition (IPC), however, can reduce the injury. In clinical practice, the sequential application and release of tourniquets is often used in bilateral total knee replacement (TKR) to obtain a clearer operative field, but the effects on the production of free radicals and lipid peroxidation have not been studied. In this study, we have observed the production of free radicals and the subsequent lipid peroxidation in bilateral TKR with sequential application of a tourniquet to examine the effect of IPC. Patients undergoing elective TKR under intrathecal anaesthesia were studied. Blood samples were obtained after spinal anaesthesia, one minute before and five and 20 minutes after release of each tourniquet. We used the lucigenin chemiluminescence analysis and the phosphatidylcholine hydroperoxide (PCOOH) assay to measure the production of ROS and lipid peroxidation. Our results showed that production of ROS significantly increased at five and 20 minutes after release of the first tourniquet and at five minutes after release of the second tourniquet, but returned to normal at 20 minutes after the second reperfusion. The peak production of ROS was at 20 minutes after the first reperfusion; lipid peroxidation did not change significantly. We conclude that in spite of significant production of ROS after the release of tourniquet, the IPC phenomenon occurs during bilateral TKR with sequential application of a tourniquet

Aims

This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys.

In this study of 41 patients, we used proteomic, Western blot and immunohistochemical analyses to show that several reactive oxygen species scavenging enzymes are expressed differentially in patients with primary osteoarthritis and those with non-loosening and aseptic loosening after total hip replacement (THR). The patients were grouped as A (n = 16, primary THR), B (n = 10, fixed THR but requiring revision for polyethylene wear) and C (n = 15, requiring revision due to aseptic loosening) to verify the involvement of the identified targets in aseptic loosening. When compared with Groups A and B, Group C patients exhibited significant up-regulation of transthyretin and superoxide dismutase 3, but down-regulation of glutathione peroxidase 2 in their hip synovial fluids. Also, higher levels of superoxide dismutase 2 and peroxiredoxin 2, but not superoxide dismutase 1, catalase and glutathione perioxidase 1, were consistently detected in the hip capsules of Group C patients.

We propose that dysregulated reactive oxygen species-related enzymes may play an important role in the pathogenesis and progression of aseptic loosening after THR.

Implant-associated infection is a major source of morbidity in orthopaedic surgery. There has been extensive research into the development of materials that prevent biofilm formation, and hence, reduce the risk of infection. Silver nanoparticle technology is receiving much interest in the field of orthopaedics for its antimicrobial properties, and the results of studies to date are encouraging. Antimicrobial effects have been seen when silver nanoparticles are used in trauma implants, tumour prostheses, bone cement, and also when combined with hydroxyapatite coatings. Although there are promising results with in vitro and in vivo studies, the number of clinical studies remains small. Future studies will be required to explore further the possible side effects associated with silver nanoparticles, to ensure their use in an effective and biocompatible manner. Here we present a review of the current literature relating to the production of nanosilver for medical use, and its orthopaedic applications.

Cite this article: Bone Joint J 2015; 97-B:582–9.

In an attempt to increase the life of cementless prostheses, an hydroxyapatite-coated implant which releases a bisphosphonate has been suggested as a drug-delivery system. Our in vitro study was designed to determine the maximum dose to which osteoblasts could be safely exposed.

Our findings demonstrated that zoledronate did not impair the proliferation of human osteoblasts when used at concentrations below 1 μm. Murine cells can be exposed to concentrations as high as 10 μm.

A concentration of 0.01% of titanium particles did not impair the proliferation of either cell line. Zoledronate affected the alkaline phosphatase activity of murine osteoblasts through a chelation phenomenon. The presence of titanium particles strongly decreased the alkaline phosphatase activity of murine osteoblasts. We did not detect any synergic effect of zoledronate and titanium particles on the behaviour of both human and murine osteoblasts.