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PubMed2005

Universal primers for detection of common bacterial pathogens causing prosthetic joint infection.

The diagnosis of low grade prosthetic joint infection is difficult and time consuming. Nested-PCR for universal bacterial DNA segments detection of "orthopaedic" bacteria was tested in a laboratory setting. This method is based on amplification of the 16S bacterial ribosomal RNA coding sequences. 11 species of the most frequent bacterial pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecium, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Serratia marcescens) involved in prosthetic joint infections were studied. All could be detected rapidly and sensitively by this method.

Bacteria↗
PubMed1998

In vitro, in vivo, and tissue retrieval studies on particulate debris.

The biologic effects of wear debris are an important factor limiting the longevity of total joint replacements. In vivo, in vitro, and tissue retrieval studies have underlined a central role for the macrophage in the etiology of loosening and periprosthetic osteolysis. Wear particles from the materials used for total joint replacement activate macrophages to secrete proinflammatory factors. Complex interactions between macrophages and other cells stimulate bone resorption and suppress bone formation at the prosthetic interface. To improve the long term outcome of joint replacements, future research must find innovative approaches to minimize the production and biologic effects of wear debris.

Animals↗
PubMed1987

Non-gonococcal infectious arthritis: a retrospective study.

In a retrospective study the outcome of non-gonococcal infectious arthritis was evaluated in 76 adult patients admitted to the Leiden University Hospital between 1970 and 1984. The mortality rate was 12%, and complete recovery was achieved in only 19 of the 76 patients (25%). Each of the following had a significantly unfavourable influence on the residual joint function: duration of infection more than 14 days, female sex, presence of rheumatoid arthritis, and presence of a joint prosthesis.

Adolescent↗
PubMed2003

Theoretical investigation of an artificial joint with micro-pocket-covered component and biphasic cartilage on the opposite articulating surface.

This paper presents a theoretical investigation of a geometrically idealized artificial joint with micro-pocket-covered component and biphasic cartilage on the opposite articulating surface. The fluid that exudes from the biphasic cartilage fills and pressurizes the micro-pockets. In this way, a poro-elasto-hydrodynamic regime of lubrication is developed. Assuming that lower friction would result in lower adhesive wear, and neglecting the fatigue as well as the abrasive wear, the proposed bearing system hypothetically could reduce the amount of wear debris. Equations of the linear biphasic theory are applied for the confined and unconfined compression of the cartilage. The fluid pressure and the elastic deformation of the biphasic cartilage are explicitly presented. The effective and equilibrium friction coefficients are obtained for the particular configuration of this bearing system. The micro-pockets geometrical parameters (depth, radius, surface distribution and edge radius) must be established to reduce the local contact stresses, to assure low friction forces and to minimize the biphasic cartilage damage. The influence of the applied pressure, porosity of the micro-pocket-covered component, filling time, cartilage elasticity, permeability and porosity upon the micro-pockets depth is illustrated. Our results are based upon the previously published data for a biphasic cartilage.

Biomimetic Materials↗
PubMed1998

Contact stress at articular surfaces in total joint replacements. Part II: Analytical and numerical methods.

In this second part of the series of reviews, attention focuses on analytical and numerical methods that have been used to estimate the magnitude of the contact stress in: models of articular joints; models of total joint replacements, without and with the associated joint; or models of simple physical systems that are deemed to have relevance to conditions at articular surfaces in arthroplasties. Three main recommendations emerge from this review. First, analytical methods should be avoided. Second, for numerical studies, the nonlinear contact finite element method should be used. Third, more work is needed in many areas, an example of which is the effect of the method of sterilization of tibial inserts on the estimated contact stress at the tibiofemoral interface in knee implants.

Alloys↗
PubMed1988

The use of large allografts for tumor reconstruction and salvage of the failed total hip arthroplasty.

Large bone defects have become a more common orthopedic problem in recent year. This is due to the increased enthusiasm for limb salvage surgery as a technique to manage patients with primary bone tumors and for patients who have had multiple joint arthroplasties with subsequent bone loss. One technique that has proven successful for this difficult problem is the use of fresh frozen allografts to reconstruct these skeletal defects. From January 1981 until January 1987, 60 large fragment fresh frozen allografts were used for skeletal reconstruction. These grafts were divided into three basic groups: intercalary, 15; osteoarticular, 16; and allograft-prosthetic composite, 29. The diagnoses included 43 bone tumors, 16 failed total hip arthroplasties, and one traumatic bone loss. The average patient age was 39.7 years and had an average follow-up period of 24 months. The average length of allograft was 12.4 cm. Using the Enneking Functional Evaluation System, the final functional analysis revealed excellent or good results in 86% of the patients and fair or poor results in 14% of the patients. Roentgenological union at the allograft-host bone junction was achieved in 90% of the patients in a mean time of 5.8 months after surgery. An additional three patients obtained union after autogeneic bone grafting. At the time of follow-up evaluation, 92.3% of the patients were free of tumor; they had no local recurrences. The use of fresh frozen allografts represents an acceptable alternative for the reconstruction of large skeletal defects. One can expect good or excellent function for the majority of patients. The best functional results were obtained with the intercalary allografts and the allograft-prosthetic composites.

Adolescent↗
PubMed2000

Results of arthroscopic joint debridement in different stages of chondromalacia of the knee joint.

A retrospective study was performed of 161 patients who had undergone arthroscopic operation for chondromalacia of the knee joint. After an average follow-up period of 40 (range 10-72) months, patients with severe articular cartilage lesions who had undergone articular lavage alone showed significantly poorer results (P < 0.001). With the same stage of chondromalacia and having undergone the same surgical procedure, younger patients showed better results than older patients. The more effective interruption of the circulus vitiosus during the development of degenerative joint diseases is the primary cause for better results achieved by mechanical debridement of the joint for patients suffering from grade 2 or higher. According to the literature, aggressive subchondral abrasion in severely degenerated knees does not show any benefits. Apparently, the success of the therapy depends to a great extent on the inferiority of the potential degenerative regenerate (lack of capacity of intrinsic regeneration of the hyaline cartilage) as well as on the grade and the progression of chondromalacia. Almost every second patient suffering from grade 4 chondromalacia complained of recurrent pain 1 year postoperatively. One of every 6 patients received a knee joint prosthesis within the 1st year. Therefore, the patients' preoperative expectations have to be clearly objectified. The surgical procedure as an operation with a low complication risk can also be justified as a temporary alternative to total knee arthroplasty in patients suffering from a high-grade degeneration of the joint.

Adult↗
PubMed1988

Shoulder arthroplasty with the Neer Mark-II prosthesis.

Total shoulder joint replacement was used as primary intervention in 50 shoulders--35 with rheumatoid arthritis, eight with osteoarthritis, and seven with traumatic arthritis. Follow-up time was 27 (12-42) months. The primary indication for the operation was chronic severe pain; improvements in motion and function were secondary objectives. Relief of pain was obtained in 46 of 50 shoulders. The best results regarding pain, motion, and function were obtained in the osteoarthritic group. The majority of patients with rheumatoid arthritis obtained pain relief and the largest increase in range of motion occurred in this group, although full range of motion was never regained. The results in patients with traumatic arthritis seemed unpredictable. Two shoulders were complicated by glenoid loosening, one by humeral subluxation, and one by musculocutaneous nerve palsy.

Arthritis↗
PubMed1993

Revision procedures for complications of surgery for osteoarthritis of the carpometacarpal joint of the thumb.

Between the years 1980 to 1987, 17 patients had revision procedures for complications of surgery for osteoarthritis of the carpometacarpal joint of the thumb. 12 followed silastic implant arthroplasty, four trapeziectomy and one arthrodesis. The failed silastic arthroplasties were treated by removal of the implant, and soft tissue arthroplasty in eight, revision with another implant in three and intermetacarpal bone grafting in one. Patients with metacarpo-scaphoid arthritis after trapeziectomy were treated by silastic implant arthroplasty in three and fusion in one. Nine of the 17 revision procedures (53%) had good, three (18%) fair and five (29%) poor results respectively.

Adult↗
PubMed2004

Prediction of scratch resistance of cobalt chromium alloy bearing surface, articulating against ultra-high molecular weight polyethylene, due to third-body wear particles.

The entrapment of abrasive particles within the articulation between a cobalt chromium alloy (CoCrMo) femoral component and an ultra-high molecular weight polyethylene (UHMWPE) cup of artificial hip joints or tibial inserts of artificial knee joints usually scratches the metallic bearing surface and consequently increases the surface roughness. This has been recognized as one of the main causes of excessive polyethylene wear, leading to osteolysis and loosening of the prosthetic components. The purpose of this study was to use the finite element method to investigate the resistance of the cobalt chromium alloy bearing surface to plastic deformation, as a first approximation to causing scratches, due to various entrapped debris such as bone, CoCrMo and ZrO2 (contained in radiopaque polymethyl methacrylate cement). A simple axisymmetric micro contact mechanics model was developed, where a spherical third-body wear particle was indented between the two bearing surfaces, modelled as two solid cylinders of a given diameter, under the contact pressure determined from macro-models representing either hip or knee implants. The deformation of both the wear particle and the bearing surfaces was modelled and was treated as elastic-plastic. The indented peak-to-valley height on the CoCrMo bearing surface from the finite element model was found to be in good agreement with that reported in a previous study when the third-body wear particle was assumed to be rigid. Under the physiological contact pressure experienced in both hip and knee implants, ZrO2 wear particles were found to be fully embedded within the UHMWPE bearing surface, and the maximum von Mises stresses within the CoCrMo bearing surface reached the corresponding yield strength. Consequently, the CoCrMo bearing surface was deformed plastically and the corresponding peak-to-valley height (surface roughness) was found to increase with both the hardness and the size of the wear particle. Even in the case of CoCrMo wear particles, with similar mechanical properties to those of the CoCrMo bearing surface, a significant plastic deformation of the bearing surface was also noted; this highlighted the importance of considering the deformation of the wear particles. These findings support the hypotheses made by clinical studies on the contribution of entrapped debris to increased surface roughness of CoCrMo femoral bearing surfaces.

Compressive Strength↗
PubMed2004

Successful treatment of Staphylococcus epidermidis hip prosthesis infection with oral linezolid.

OBJECTIVE: To report a case of Staphylococcus epidermidis infection of a hip prosthesis successfully treated with oral linezolid. CASE SUMMARY: A 46-year-old woman developed methicillin-resistant S. epidermidis (MRSE) infection of her prosthetic hip. She received oral linezolid 600 mg twice daily for one month; after that time, the biological inflammatory markers returned to normal. DISCUSSION: One of the most serious complications of arthroplasty is joint prosthesis infection. It is mainly caused by gram-positive bacteria, in particular those of the genus staphylococcus. The increasing prevalence of gram-positive cocci that are resistant to antimicrobial agents has complicated the treatment of serious infections. CONCLUSIONS: Oral linezolid appears to be an effective and well-tolerated treatment option for hip prosthesis infections due to MRSE.

Acetamides↗
PubMed2006

Intra-articular hyaluronic acid after knee arthroscopy: a two-year study.

Arthroscopic knee joint lavage is used when conservative treatment of knee osteoarthritis is unsatisfactory and a joint prosthesis is not yet indicated. The potentially negative effect of irrigation fluids on cartilage metabolism and structure has led to the development of a temporary synovial fluid substitute containing hyaluronic acid. The short and long-term effects of this synovial fluid substitute were investigated in a total of 80 patients with persistent knee pain. Forty patients underwent arthroscopic knee joint lavage, in some cases combined with careful cartilage debridement (group A) while a further 40 patients underwent the same procedure which, after final joint lavage, was immediately followed by a single instillation of 10 ml of the synovial fluid substitute (0.5% sodium hyaluronate) into the joint (A + HA group). After the procedure, pain on walking and restricted ability to walk 100 m were markedly reduced to a comparable extent in both groups. Three months later, the effect of the treatment assessed using various parameters (CGI, restricted ability to walk 100 m, pain on walking, night pain) had decreased in group A, while it remained stable or even improved slightly in the A + HA group. The Mann-Whitney statistics revealed a descriptive superiority for the A + HA group at this time point. One year after treatment the superiority of the A + HA group was confirmed using the same assessment parameters. No side effects or adverse events were observed for either treatment procedure. This study shows that arthroscopic knee joint lavage leads to a lasting improvement in pain and functional impairment. The post-arthroscopic instillation of a HA-based synovial fluid substitute into the joint is a suitable way of achieving long-term stabilisation of the treatment outcome. This was supported by findings of a survey of 66 patients at 2 years after treatment in this study. Level I prospective, randomised controlled double-blind study.

Adjuvants, Immunologic↗
PubMed1994

Interleukin-1 production by activated macrophages surrounding loosened orthopaedic implants: a potential role in osteolysis.

IL-1 producing cells at the bone-implant interface obtained during revision of loosened total joint replacements were demonstrated by immunohistochemistry on tissue sections. Other markers for the characterization of macrophages, B cells, T cell subpopulations, IL-2 receptor and HLA-DR antigens were also used. The 10 cases examined showed excessive metallosis within the cytoplasm of the macrophages and extracellular matrix. IL-1 beta containing cells were found in seven cases, four of which showed positive staining on more than 80% of the macrophages. A relatively similar proportion of T cells was seen in all the cases. T helper (CD4 positive) cells were always present in excess of T suppressor (CD8 positive) subtype. T cells showed no expression of detectable membrane IL-2 receptor. No B cells were found in these cases. Macrophages showed very strong immunostaining for HLA-DR. These findings indicate the possible induction of IL-1 production by activated macrophages in the interface in response to the presence of metallic wear debris. In view of the well known effect of IL-1 as a potent mediator of bone lysis, the results suggest a major role of the metal debris-containing macrophages in the process of osteolysis and subsequent implant loosening.

Adult↗
PubMed1999

Wear debris and cytokine production in the interface membrane of loosened prostheses.

In this study, thirty-nine patients were examined. All of them suffered from hip joint prostheses loosening and underwent revision surgery. Bioptic samples were collected at the interface between bone and implant either at the stem or cotyle level. Immunohistochemistry was performed to detect IL-1alpha, IL-1beta, IL-6 and TNF, cytokines that directly cause bone resorption and indirectly induce synthesis of other bone resorbing cytokines. Quantitative analysis of the positive cells and correlation with clinical data was performed. It resulted that there is a great variability in positive cells for cytokines according to the harvest site; anyway, cytokines tend to be higher in patients carrying a joint prosthesis with polyethylene acetabular component and it is associated with plastic wear particles, even though there is no direct correlation between wear amount and cytokine levels. There is a statistically significant negative correlation between metal wear and a cytokine (IL-6); cytokines levels do not depend on the implant time to failure and do not correlate with pain score. As expected, cytokines levels tend to be lower in subjects being treated with non-steroidal antiinflammatory drugs. It can be concluded that plastic wear is the factor inducing the highest cytokine levels in the tissues around the prosthesis at the interface; cytokines that are an indicator of osteolysis risk.

Adult↗
PubMed1988

The role of macrophages and giant cells in loosening of joint replacement.

Macrophages and foreign-body giant cells from the bone-cement interface of loosened joint replacement were assayed for direct bone resorption in an in vitro experimental model. Human osteoclasts from giant cell tumors and experimental animal osteoclasts were not capable of resorbing the bone under experimental conditions, but osteoclasts are. It is suggested that macrophages and giant cells in loosened implants may initiate bone resorption, removing the extra-cellular barrier that normally protects mineral crystals from osteoclastic recognition.

Aged↗
PubMed1999

Step activity monitor: increased accuracy in quantifying ambulatory activity.

This study compares the accuracy of a two-dimensional accelerometer worn on the ankle (a step activity monitor) with that of an electronic, digital pedometer worn on the belt line. Twenty-nine human subjects were evaluated while they briskly walked 400 M, slowly walked 10 M, and ascended and descended a flight of stairs. The step activity monitor had less error in all activities; its mean absolute error was 0.54%, whereas that of the pedometer was 2.82%. The difference was more pronounced in obese subjects (body mass index greater than 30), with an overall mean absolute error of 0.48% for the step activity monitor and 6.12% for the pedometer (nearly 13 times that of the step activity monitor). For subjects with a body mass index less than 30, the step activity monitor had an overall error of 0.56% and the pedometer had an overall error of 1.56% (less than 3 times that of the step activity monitor). The absolute error of the pedometer was positively correlated with body mass index (r = 0.792, p < 0.0001) and weight (r = 0.753, p < 0.0001), whereas the error of the step activity monitor was not significantly correlated with either. Neither device was significantly biased by age, gender, or the presence of a lower-extremity joint prosthesis. The accuracy and additional capabilities, including a real-time memory record of activity, of the step activity monitor make it well suited for objectively quantifying ambulatory activity, especially for obese subjects.

Acceleration↗