Osteolysis and periprosthetic bone loss have been a concern since Charnley’s original reports of metal on Teflon. Willart and Semlitch were the first investigators to propose a biologic mechanism for osteolysis associated with particulate
Osteolysis induced by UHMWPE debris has historically been one of the major causes of long term failure of TJR. An increase in concentration of polyethylene particles in the peri-prostheic tissue has been linked to an increased incidence of osteolysis. The dual mobility hip bearing concept mates a femoral head into a polyethylene liner which has an unconstrained articulation into a metal shell. The wear mechanism of the dual mobility hip bearing is distinct from a constrained single articulation design, which may result in a difference in
Introduction. Currently, different techniques to evaluate biocompatibility of orthopaedic materials, including two-dimensional (2D) cell culture for metal and ceramic
Particulate
Major long-term complication of total hips is osteolysis in the more active patients. Osteolysis is a result of the biological response to the
Summary Statement. The chemistry, amount, morphology, and size distribution of
Introduction:. Unicompartmental knee arthroplasty (UKA) has been used in the past decades to treat progressive cartilage degeneration in a single compartment. Concern has been raised over the rate of revision procedures for polyethylene wear and osteoarthritic progression into the adjacent compartment. Few studies have examined the pathology of cartilage degeneration in the setting of UKA. This study aims to investigate the viability of knee chondrocytes introduced to high and low concentrations of orthopaedic
Introduction.
The production of particulate
Between 1995 and 1998, eighty revision total knee arthroplasties were done for the primary reason of advanced polyethylene wear. The primary arthroplasties prosthesis that failed included thirty-four mobile bearing knees and forty-six fixed bearing knees. In thirty-four Low Contact Stress (LCS) mobile bearing knees, osteolysis was identified intraoperatively in sixteen knees (forty-seven per cent). There were varying of fixation methods included nine cemented, four cementless and three hybrids. In forty-six fixed bearing knees, osteolysis was identified intraoperatively in six knees (thirteen per cent). The fixation methods of prostheses included two cemented and four cementless. The incidence of osteolysis was statistically significant difference between the mobile bearing and fixed bearing knees (p<
0.02). Both scattering electron microscope (SEM) and light scattering analysis were used to examine the UHMWPE
Joint replacement implants, especially in their modular forms, are subjected to wear and corrosion at various sites in their articulation, such as the bearing surfaces, the undersurface of the insert, the femoral head-neck junction and the implant or polymethylmethacrylate-bone interface. Movement of the bearing surfaces is not the only cause, as faulty implant positioning can initiate wear through impingement between two parts of the articulation. These wear products of polyethelene or metal, in particulate form, are influential to the ultimate fate of the prostheses through the initiation of local and systemic immune reactions. These debris are phagocytised by macrophages and phagocytised proteins are partly degraded in intracellular vesicles, where they become associated with the major histocompatability complex molecule HLA-DR. This molecule when transported to the cell membrane, interacts with CD4+ lymphocytes to activate an immune response and initiate the production of interleukin1b, interleukin 6 and tumor necrosing factor a. These cytokines mediate the inflammatory response and activate osteoclasts causing periprosthetic osteolysis. Polyethelene and metal wear particles, in addition to their local effects, can be disseminated beyond the periprosthetic tissues and reach distant organs and regional lymphnodes. The concentrations of certain elements of metallic implants, such as iron, cobalt, chromium or titanium have been detected in lymphnodes, the liver and the spleen in levels a lot higher than normal, especially in patients with loose prostheses and, less so, in patients with stable prostheses. The reported values of metal ions in published series vary. Thus certain investigators (Brodner et al) have reported continuous systemic cobalt release during a five year follow-up period and in levels slightly above detection values, while others (Clarke et al, Lohtka et al) have reported consistently high levels of cobalt and chromium ions in metal on metal articulations. The diameter of the femoral head appears to be a significant factor. In surface hip replacements with large diameter heads the amount of detected metal ions was significantly higher compared with total hip replacements with use of 28mm diameter femoral heads. In that type of replacement the levels of cobalt was 50 times higher than normal and of chromium 100 times higher. Polyethelene particles, similarily have been detected in paraaortic lymphnodes in percentages similar to metal ions. However the detection of PE particles in the liver or the spleen was less, compared to metal ions, possibly due to the difficulty of modern methods to detect PE particles of submicrometre size. The relevance of the dissemination of metal ions and of PE
Pain in the distribution of the sciatic nerve is common in the elderly. In the presence of a long-standing joint replacement, consideration should be given as to whether compression might be due to an extraspinal cause. We present three women, in whom a mass of
The authors wished to determine if macrophage activation and the release of osteolytic cytokines in response to orthopaedic
The current long term results of total joint arthroplasty are limited by mechanical wear of the implants with an associated immune mediated bone lysis with subsequent loosening and eventual failure. It has been demonstrated that the osteolysis seen in cases of aseptic loosening is mediated by the immune system, particularly, both directly and indirectly, by activated macrophages. Macrophages indirectly cause osteolysis through release of the osteoclast activating cytokines: TNFα, IL-1 and PGE2 and also directly resorb bone in small amounts when activated by wear particles. We wished to determine if macrophage activation and the release of osteolytic cytokines in response to orthopaedic
Summary. We report the first use of synchrotron xray spectroscopy to characterize and compare the chemical form and distribution of metals found in tissues surrounding patients with metal-on-metal hip replacements that failed with (Ultima hips) or without (current generation, large diameter hips) corrosion. Introduction. The commonest clinical category of failure of metal-on-metal (MOM) hip replacements is “unexplained” and commonly involved a soft tissue inflammatory response. The mechanism of failure of the Ultima MOM total hip replacement includes severe corrosion of the metal stem and was severe enough to be removed from clinical use. Corrosion is not a feature that we have found in the currently used MOM bearings. To better understand the biological response to MOM
Background. Wear particles are considered to be the major culprit for the aseptic loosening. Their characterization is thus crucial for the understanding of their bioreactivity and contribution to the development of aseptic loosening. Methods. Metal
Statement of Purpose:. The wear rate of Ultra High Molecular Weight Polyethylene (UHMWPE) in joint replacements has been correlated to both contact area and contact stress in the literature, [1], [2]. In both publications and our experiment, UHMWPE articulated with a polished surface of cobalt-chromium alloy was evaluated using a Pin-On-Disk (POD) apparatus (AMTI) implementing bi-directional movement. In publication [1], volumetric wear was independent of normal load and dependent upon increasing contact area. The results demonstrated that increasing contact stress decreased wear rates twofold. In publication [2], at maximum cross-shear, wear was proportional to nominal contact area and wear factors normalized to area are more appropriate than load based wear factors. In both studies, the contact surface areas of the POD pins were reduced by decreasing the diameters of the POD Pins. In our experiment, the contact area was dependent on textured POD Pin 390 (T390) which had low wear [3]. T390 reduced the normal POD contact area from 71 mm. 2. to 8.26 mm. 2. Hydroxylapatite (HA) particles were introduced to the serum to simulate third body
There have been numerous reports regarding “pseudotumor” associated with hip arthroplasty. We present two reports in which main etiology in the pseudotumor formation was titanium (Ti), but not cobalt-chromium (Co-Cr). We should keep in mind that Ti analysis is essential in some cases. (Case 1) A 68-year-old male presented to our institution because of right hip pain and lower extremity swelling four years after a bipolar hemiarthroplasty. MRI predicted a cystic pseudotumor. However, revision surgical findings showed no apparent cause of ARMD previously described in the literatures. Postoperative analysis showed that the metal debris mainly originated from the Ti alloy itself. (Case reports in Orthopedics, vol.2014, Article ID 209461, 4 pages) (Case 2) A 77-year-old female presented to our institution because of right hip pain and swelling six years after a total hip arthroplasty using a cable trochanteric reattchment. Plain radiographs demonstrated evidences of severe osteolysis and multiple fragments of the broken cable. However, MRI predicted a psudotumor(See Figure 1). Postoperative analysis clarified that main etiology in the pseudotumor formation was the stem mede of Ti, but not the cable made of Co-Cr.