Cause Of Prosthetic Failure Research Articles

Early Clinical Outcomes of Arthroscopic Management of the Failing Alloplastic Temporomandibular Joint Prosthesis

Total joint replacement is the recommended treatment for end-stage temporomandibular joint (TMJ) disease. The goal of treatment is to help the return to acceptable function with improvement of the maximum incisal opening (MIO) and a reduction of pain. When a prosthetic joint shows late complications, surgical management includes an open approach, with debridement, cultures, and prosthetic replacement as options. The purpose of the present study was to evaluate the early outcomes of arthroscopic management of failing prosthetic TMJs (PTMJs). The inclusion criteria were patients with custom or stock joints with complaints of limitation of mouth opening and pain, who had undergone arthroscopy. The exclusion criteria were patients with radiographic heterotopic bone formation, improvement with antibiotic treatment, and failed hardware found on imaging studies. A total of 9 patients were included in the present study (all women), with 5 unilateral and 4 bilateral PTMJs, for a total of 13 sides that underwent arthroscopy. Their mean age was 40years (range, 23 to 65years). The mean preoperative MIO was 25mm, and the mean preoperative visual analog scale for pain and functional limitation scores were both 8 of 10. The corresponding scores were 4 of 10 and 3 of 10 at 3months postoperatively. Arthroscopic management of prosthetic joints has been reported in orthopedic studies, with benefits shown in the diagnosis and management of synovial impingement and arthrofibrosis. The results from the present study demonstrated that the early clinical outcomes of arthroscopic management of PTMJs is promising for decreasing pain and increasing the MIO. Larger studies with longer follow-up are needed to further classify the different causes of prosthetic failure and advance the approaches to management.

Establishment and validation of a nomogram model for aseptic loosening after tumor prosthetic replacement around the knee: a retrospective analysis

BackgroundAseptic loosening has become the main cause of prosthetic failure in medium- to long-term follow-up. The objective of this study was to establish and validate a nomogram model for aseptic loosening after tumor prosthetic replacement around knee.MethodsWe collected data on patients who underwent tumor prosthetic replacements. The following risk factors were analyzed: tumor site, stem length, resection length, prosthetic motion mode, sex, age, extra-cortical grafting, custom or modular, stem diameter, stem material, tumor type, activity intensity, and BMI. We used univariate and multivariate Cox regression for analysis. Finally, the significant risk factors were used to establish the nomogram model.ResultsThe stem length, resection length, tumor site, and prosthetic motion mode showed a tendency to be related to aseptic loosening, according to the univariate analysis. Multivariate analysis showed that the tumor site, stem length, and prosthetic motion mode were independent risk factors. The internal validation indicated that the nomogram model had acceptable predictive accuracy.ConclusionsA nomogram model was developed for predicting the prosthetic survival rate without aseptic loosening. Patients with distal femoral tumors and those who are applied with fixed hinge and short-stem prostheses are more likely to be exposed to aseptic loosening.

Reconstruction with modular megaprostheses for sarcomas of the lower extremity.

Limb-preserving surgery using modular megaprostheses for the reconstruction of large skeletal defects is currently the preferred treatment for sarcomas. The authors report the postoperative outcomes after skeletal resection for lower extremity sarcomas and the use of the METS cemented modular implant system (Stanmore Implants, Hertfordshire, United Kingdom) for reconstruction. They retrospectively studied 52 consecutive patients operated on from 2003 to 2012. There were 27 distal femur prostheses, 13 proximal femur, 11 proximal tibia, and 1 total femur implants. Patients were followed for a mean of 4.3 years. Overall patient survival, prosthesis survival, limb salvage rate, and secondary complications were documented. Five years postoperatively, prosthesis survival was 79%. Complications warranting implant revision surgery were documented in 15% of patients, whereas complications warranting surgery of any kind were observed in 27% of the patients. Nonmechanical complications, namely local relapse of the tumor and prosthetic infection, were the most common cause of prosthetic failure, accounting for 88% of major revision surgeries and 100% of amputations. Mechanical complications were rare, observed in only 6% of patients. No patients required secondary revision surgery. The limb salvage rate was 89%. Overall patient survival was 79% at 5 years and 71% at 10 years. The low risk for mechanical complications and the high limb salvage rate support the use of the METS modular megaprostheses for the reconstruction of skeletal defects following lower limb sarcoma surgery.

Technique for systematic bone reduction for fixed implant-supported prosthesis in the edentulous maxilla

Bone reduction for maxillary fixed implant-supported prosthodontic treatment is often necessary to either gain prosthetic space or to conceal the prosthesis-tissue junction in patients with excessive gingival display (gummy smile). Inadequate bone reduction is often a cause of prosthetic failure due to material fractures, poor esthetics, or inability to perform oral hygiene procedures due to unfavorable ridge lap prosthetic contours. Various instruments and techniques are available for bone reduction. It would be helpful to have an accurate and efficient method for bone reduction at the time of surgery and subsequently create a smooth bony platform. This article presents a straightforward technique for systematic bone reduction by transferring the patient’s maximum smile line, recorded clinically, to a clear radiographic smile guide for treatment planning using cone beam computed tomography (CBCT). The patient’s smile line and the amount of required bone reduction are transferred clinically by marking bone with a sterile stationery graphite wood pencil at the time of surgery. This technique can help clinicians to accurately achieve the desired bone reduction during surgery, and provide confidence that the diagnostic and treatment planning goals have been achieved.

Nuclear medicine and the failed joint replacement: Past, present, and future.

Soon after the introduction of the modern prosthetic joint, it was recognized that radionuclide imaging provides useful information about these devices. The bone scan was used extensively to identify causes of prosthetic joint failure. It became apparent, however, that although sensitive, regardless of how the images were analyzed or how it was performed, the test was not specific and could not distinguish among the causes of prosthetic failure. Advances in anatomic imaging, notably cross sectional modalities, have facilitated the diagnosis of many, if not most, causes of prosthetic failure, with the important exception of infection. This has led to a shift in the diagnostic paradigm, in which nuclear medicine investigations increasingly have focused on diagnosing infection. The recognition that bone scintigraphy could not reliably diagnose infection led to the development of combined studies, first bone/gallium and subsequently leukocyte/bone and leukocyte/marrow imaging. Labeled leukocyte imaging, combined with bone marrow imaging is the most accurate (about 90%) imaging test for diagnosing joint arthroplasty infection. Its value not withstanding, there are significant disadvantages to this test. In-vivo techniques for labeling leukocytes, using antigranulocyte antibodies have been explored, but have their own limitations and the results have been inconsistent. Fluorodeoxyglucose (FDG)-positron emission tomography (FDG-PET) has been extensively investigated for more than a decade but its role in diagnosing the infected prosthesis has yet to be established. Antimicrobial peptides bind to bacterial cell membranes and are infection specific. Data suggest that these agents may be useful for diagnosing prosthetic joint infection, but large scale studies have yet to be undertaken. Although for many years nuclear medicine has focused on diagnosing prosthetic joint infection, the advent of hybrid imaging with single-photon emission computed tomography(SPECT)/electronic computer X-ray tomography technique (CT) and the availability of fluorine-18 fluoride PET suggests that the diagnostic paradigm may be shifting again. By providing the anatomic information lacking in conventional radionuclide studies, there is renewed interest in bone scintigraphy, performed as a SPECT/CT procedure, for detecting joint instability, mechanical loosening and component malpositioning. Fluoride-PET may provide new insights into periprosthetic bone metabolism. The objective of this manuscript is to provide a comprehensive review of the evolution of nuclear medicine imaging of joint replacements.

Prosthetic joint infections: radionuclide state-of-the-art imaging

Prosthetic joint replacement surgery is performed with increasing frequency. Overall the incidence of prosthetic joint infection (PJI) and subsequently prosthesis revision failure is estimated to be between 1 and 3%. Differentiating infection from aseptic mechanical loosening, which is the most common cause of prosthetic failure, is especially important because of different types of therapeutic management. Despite a thorough patient history, physical examination, multiple diagnostic tests and complex algorithms, differentiating PJI from aseptic loosening remains challenging. Among imaging modalities, radiographs are neither sensitive nor specific and cross-sectional imaging techniques, such as computed tomography and magnetic resonance imaging, are limited by hardware-induced artefacts. Radionuclide imaging reflects functional rather than anatomical changes and is not hampered by the presence of a metallic joint prosthesis. As a result scintigraphy is currently the modality of choice in the investigation of suspected PJI. Unfortunately, there is no true consensus about the gold standard technique since there are several drawbacks and limitations inherent to each modality. Bone scintigraphy (BS) is sensitive for identifying the failed joint replacement, but cannot differentiate between infection and aseptic loosening. Combined bone/gallium scintigraphy (BS/GS) offers modest improvement over BS alone for diagnosing PJI. However, due to a number of drawbacks, BS/GS has generally been superseded by other techniques but it still may have a role in neutropenic patients. Radiolabelled leucocyte scintigraphy remains the gold standard technique for diagnosing neutrophil-mediated processes. It seems to be that combined in vitro labelled leucocyte/bone marrow scintigraphy (LS/BMS), with an accuracy of about 90%, is currently the imaging modality of choice for diagnosing PJI. There are, however, significant limitations using in vitro labelled leucocytes and considerable effort has been devoted to developing alternative radiotracers, such as radiolabelled HIGs, liposomes, antigranulocyte antibodies and fragments, as well as more investigational tracers such as radiolabelled antibiotics, antimicrobial peptides, bacteriophages and thymidine kinase. On the other hand, positron emission tomography (PET) is still growing in the field of PJI imaging with radiotracers such as (18)F-fluorodeoxyglucose (FDG), (18)F-FDG white blood cells and (18)F-fluoride. But unfortunately this superb tomographic technique will only receive full acceptance when specific PET uptake patterns can be successfully developed. The emergence of hybrid modality imaging using integrated single photon emission computed tomography (SPECT) and PET with computed tomography (SPECT/CT and PET/CT) may also have a contributing role for more accurate assessment of joint replacement complications, especially combined with new radiotracers such as (68)Ga and (64)Cu. Finally, in searching for infection-specific tracers, currently there is no such diagnostic agent available.

The impact of amount of bone resection on uncemented prosthesis failure in patients with a distal femoral tumor

Previous reports on the correlation between the amount of bone resection and prosthetic failure might be confounded by variability in the amount of soft tissue resected and by the mode of prosthesis fixation. We analyzed 117 patients who underwent intra-articular resection and cementless modular tumor prosthetic reconstruction for a distal femoral tumor. Mean follow-up duration was 95 months (range, 15-271 months). Associations between the prognostic variables and prosthesis survival were assessed. A receiver operating characteristic (ROC) curve was plotted for resection percentage to predict prosthetic failure. Prostheses were removed in 35 (30%) patients for; infection (17), local recurrence (5), loosening (7), stem fracture (4), or periprosthetic fracture (2). The 10-year prosthetic survivals of the 117 implants were 65.2 ± 5.4%. A percentage bone resection (>40%) was found to be associated with mechanical prosthesis failure by multivariate analysis (P = 0.003). ROC curve analysis demonstrated that an optimal cut-off point of 43% for resection percentage had a sensitivity of 95.9% and a specificity of 45.5% for predicting mechanical prosthesis failure. Infection is the major cause of prosthetic failure, and amount of bone resection is negatively correlated with implant longevity.

Influence of hydroxyapatite particle characteristics on the [K]/[Na] ratio: a human monocytes in vitro study

Research in bone substitutes has shown that calcium phosphates, particularly hydroxyapatite are well adapted to use in prosthetics. Due to its characteristics that are close to those of bone, hydroxyapatite is used as a coating or bone defect filler. At long term, one of causes of prosthetic failure is bone lysis followed by aseptic loosening. Particles released at the implantation site may be one cause of this phenomenon. It is important to address the loosening problem because longer implantation times are now required due to the increasing life expectancy of the population. To understand these effects and to optimise implantation of hydroxyapatite based prostesis, simulated wear debris produced by hydroxyapatite powders of various shapes, sizes and sintering temperatures were introduced into cultured human monocytes. Monocytes were chosen because they are among the first cells to colonise the inflammatory site. Cellular alteration caused by the particles is evaluated by measuring intracellular potassium to sodium ratios. Elemental intracellular ionic concentrations were measured in cells close to the physiological state by using cryomethods combined with electron probe microanalysis. This study demonstrated that various powder characteristics influence cellular viability. It was found that needle shaped particles are the most toxic whereas powders with particle size greater than 30 μm are the least toxic.

Analysis of retrieved polymer fiber based replacements for the ACL

The present retrospective analysis of 117 surgically excised anterior cruciate ligament (ACL) prostheses was designed to elucidate the etiology and mechanisms of failure of synthetic ligamentous prostheses. They were harvested from young and active patients (26±7 yrs) at various orthopaedic centers in France between 1983 and 1993. The average duration of implantation of augmentation and replacement prostheses were 21.5±12.6 and 33.2±25.3 months, respectively. The principal causes for their excision were ruptures and synovitis. Each ACL prosthesis was examined macroscopically, histologically, and, after tissue removal, by scanning electron microscopy (SEM) to determine the model, manufacturer, surgical technique used at implantation, the extent of healing, the site of rupture, and the morphology of the damaged fibers. Fourteen types of ACL prostheses were analysed, each fabricated using a different combination of polymers, fibers and textile constructions. Consequently, they generated a variety of healing characteristics and mechanical responses in vivo. SEM observations revealed that abrasion of the textile fibers as a result of yarn-on-yarn and/or yarn-on-bone contact was a common phenomenon to almost all models, and was the primary cause of prosthetic failure. Healing inside the synthetic ACL was poorly organized, incomplete and unpredictable as the extent of collagenous infiltration into the textile structure did not increase with the duration of implantation. In fact, the collagenous infiltration into certain models appeared to be more detrimental than beneficial since it caused deterioration and fraying of the textile structure rather than serving as a reinforcing matrix around the prosthesis. In conclusion, the present study shows that three mechanisms may be involved in the failure of ACL prostheses: (1) inadequate fiber abrasion resistance against osseous surfaces; (2) flexural and rotational fatigue of the fibers, and (3) loss of integrity of the textile structure due to unpredictable tissue infiltration during healing.

CT evaluation of prosthetic ossicular reconstruction procedures: what the otologist needs to know.

Postoperative otologic evaluation of patients who have undergone ossicular reconstruction is often difficult. However, thin-section computed tomography (CT) can help determine the type of prosthesis used for reconstruction and adequately assess for complications that may be causing postoperative conductive hearing loss. A variety of prostheses may be used in ossicular reconstruction (eg, stapes prosthesis, incus interposition graft, Applebaum prosthesis, Black oval-top prosthesis, Richards centered prosthesis, Goldenberg prosthesis) and can usually be identified at CT by their shapes and locations. Several causes of prosthetic failure are readily demonstrated at CT, including recurrent cholesteatoma and otitis media, formation of granulation tissue or adhesions, and various mechanical problems (eg, subluxation, dislocation, extrusion, fracture, bending). Perilymphatic fistula can be difficult to identify at CT but may be suggested by the presence of pneumolabyrinth, unexplained middle ear effusion, or fluid accumulation within the mastoid air cells. The presence of soft tissue within the oval window niche 4-6 weeks following surgery may indicate poststapedectomy granuloma or fibrosis. Familiarity with the normal and abnormal CT appearances of ossicular prostheses will enable the radiologist to assist the otologist in identifying patients in whom revision surgery is most appropriate.

Relationship between magnitude of resection, complication, and prosthetic survival after prosthetic knee reconstructions for distal femoral tumors.

Limb-sparing surgery has become the preferred surgical treatment of malignant bone tumors. The objective of this study was to evaluate factors that influence the morbidity and outcome of prosthetic knee replacement after resection of malignant tumors of the distal femur. Eighty-two patients who had a resection of malignant tumor of the distal femur and implantation of a segmental knee prosthesis (minimum follow-up, 2 years) were retrospectively reviewed. Twenty-nine patients (35%) underwent 32 prosthetic revisions, 6 from perioperative wound complications, 13 from aseptic loosening, and 13 from other complications. The 3-, 5-, and 10-year Kaplan-Meier prosthetic survival rates were 82%, 71%, and 50%, respectively. On univariate analysis, patients who had more than 40% resection of the distal femur (P = 0.010) and those who had all their vasti muscles resected (P = 0.011) had significantly worse prosthetic survivals than the others. On multivariate analysis, resection of more than 40% of the distal femur was a significant negative prognostic factor for prosthetic survival (P = 0.017). Aseptic loosening was the primary cause of late prosthetic failure. Differences in the magnitude of resection influenced prosthetic survivorship more than prosthetic design. In the distal femoral endoprosthetic replacement, higher short- and long-term complications were found after extensive resections. Aseptic loosening was the primary cause of prosthetic failure.