Periimplant Histology and Cytokine Pattern in Metal-Allergic Knee Arthroplasty Patients with Improvement After Revision with Hypoallergenic Materials

Periarticular metal hypersensitivity complications of hip bearings containing cobalt-chromium

Hip joints with bearings composed of cobalt-chromium alloy (metal-on-metal bearings) have been one of the most widely used implants in joint replacement arthroplasty. Unfortunately, these implants can contribute to a complication called aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL), a type IV metal hypersensitivity response around the joint. Consistent with such bearings, increased metal debris can be found in the surrounding fluids and in remote tissues and organs, due to wear and corrosion. It is hypothesized that metal ions released from the prosthesis (including Co2+) can potentially form haptens with proteins such as serum albumin in synovial fluid that in turn elicit ALVAL. Generally, elevated cobalt and chromium levels in synovial fluids may indicate implant failure. However, such measurements cannot be used as a reliable tool to predict the onset of ALVAL. To detect ALVAL, some diagnostic tests, questionnaires and imaging techniques have been used clinically with some success, but a standardized approach is lacking. At present, guidelines for implant usage and patient management are ambiguous and inconsistent across health care authorities. To reduce and better manage the development of ALVAL, further research into the precise molecular mechanism(s) by which ALVAL develops is urgently needed. Identification of diagnostic and prognostic biomarkers for ALVAL is required, as are more standardized guidelines for surgery and patient management.

Metal allergy in primary and revision total knee arthroplasty : a scoping review and evidence-based practical approach

Aims

Metal allergy in knee arthroplasty patients is a controversial topic. We aimed to conduct a scoping review to clarify the management of metal allergy in primary and revision total knee arthroplasty (TKA).

Methods

Studies were identified by searching electronic databases: Cochrane Central Register of Controlled Trials, Ovid MEDLINE, and Embase, from their inception to November 2020, for studies evaluating TKA patients with metal hypersensitivity/allergy. All studies reporting on diagnosing or managing metal hypersensitivity in TKA were included. Data were extracted and summarized based on study design, study population, interventions and outcomes. A practical guide is then formulated based on the available evidence.

Results

We included 38 heterogeneous studies (two randomized controlled trials, six comparative studies, 19 case series, and 11 case reports). The evidence indicates that metal hypersensitivity is a rare complication with some histopathological features leading to pain and dissatisfaction with no reliable screening tests preoperatively. Hypoallergenic implants are viable alternatives for patients with self-reported/confirmed metal hypersensitivity if declared preoperatively; however, concerns remain over their long-term outcomes with ceramic implants outperforming titanium nitride-coated implants and informed consent is paramount. For patients presenting with painful TKA, metal hypersensitivity is a diagnosis of exclusion where patch skin testing, lymphocyte transformation test, and synovial biopsies are useful adjuncts before revision surgery is undertaken to hypoallergenic implants with shared decision-making and informed consent.

Conclusion

Using the limited available evidence in the literature, we provide a practical approach to metal hypersensitivity in TKA patients. Future national/registry-based studies are needed to identify the scale of metal hypersensitivity, agreed diagnostic criteria, and management strategies.

Cite this article: Bone Jt Open 2021;2(10):785–795.

Biological effects of metal degradation in hip arthroplasties

Metals and metal alloys are the most used materials in orthopedic implants. The focus is on total hip arthroplasty (THA) that, though well tolerated, may be associated with local and remote adverse effects in the medium-long term. This review aims to summarize data on the biological consequences of the metal implant degradation that have been attributed predominantly to metal-on-metal (MoM) THA. Local responses to metals consist of a broad clinical spectrum ranging from small asymptomatic tissue lesions to severe destruction of bone and soft tissues, which are designated as metallosis, adverse reactions to metal debris (ARMD), aseptic lymphocytic vasculitis associated lesion (ALVAL), and pseudotumors. In addition, the dissemination of metal particles and ions throughout the body has been associated with systemic adverse effects, including organ toxicity, cancerogenesis, teratogenicity, and immunotoxicity. As proved by the multitude of studies in this field, metal degradation may increase safety issues associated with THA, especially with MoM hip systems. Data collection regarding local, systemic and long-term effects plays an essential role to better define any safety risks and to generate scientifically based recommendations.

Clinical outcomes of ceramicized ball heads in total hip replacement bearings: a literature review

BACKGROUND

Metallic ball heads for total hip replacement (THR) bearings with ceramicized surfaces were introduced in orthopedics during the second half of the 1980s, with the aim of decreasing the wear of polyethylene cups.

METHODS

An analysis was made of the literature regarding outcomes for metallic ball heads with ceramicized surfaces now in clinical use (TiN, TiNbN, ZrN, monoclinic ZrO2), as well as carbon coatings (pyrolytic carbon, diamond-like carbon) and silicon nitride as coatings in ball heads for THR bearings.

RESULTS

Notwithstanding the diffusion of ceramicized ball heads in THRs, there are few reports about their clinical outcomes in hip arthroplasty. In addition, several clinical studies and some registry data are putting under scrutiny the clinical advantages of ceramicized ball heads over cobalt chrome (CoCr) alloy and ceramic ball heads.

CONCLUSIONS

The wear of THR bearings with ceramicized ball heads looks like it depends more on the behavior of the polyethylene cups than on the treatment of the ball head surface. The risk of coating damage and of its consequences has to be taken into account in selecting this type of bearing.

Hypersensitivity reactions to metal implants: laboratory options

Background

All implant compounds undergo an electrochemical process when in contact with biological fluids, as well as mechanical corrosion due to abrasive wear, with production of metal debris that may inhibit repair processes. None of the commonly-used methods can diagnose implant allergies when used singly, therefore a panel of tests should be performed on allergic patients as pre-operative screening, or when a postoperative metal sensitisation is suspected.

Methods

We analysed patients with painful prostheses and subjects prone to allergies using the Patch Test in comparison with the Lymphocyte Transformation Test. Cytokine production was evaluated to identify prognostic markers for early diagnosis of aseptic loosening. Metal debris endocytosis and cytoskeletal rearrangement was visualised by confocal microscopy.

Results

Our results demonstrate that the Lymphocyte Transformation Test can identify patients who have a predisposition to develop allergic reactions and can confirm the diagnosis of hypersensitivity in patients with painful prostheses.

The prevalence of a Th2-cytokine pattern may be used to identify predisposition to the development of allergic diseases, while the selective presence of osteoclastogenic cytokines may be used as predictor of a negative outcome in patients with painful prosthesis.

The hypothesis of the prognostic value of these cytokines as early markers of aseptic loosening is attractive, but its confirmation would require extensive testing.

Conclusions

The Lymphocyte Transformation Test is the most suitable method for testing systemic allergies. We suggest that the combined use of the Patch Test and the Lymphocyte Transformation Test, associated with cytokine detection in selected patients, could provide a useful tool for preventive evaluation of immune reactivity in patients undergoing primary joint replacement surgery, and for clinical monitoring of the possible onset of a metal sensitization in patients with implanted devices.

Allergy in total knee arthroplasty: a review of the facts

We explored the literature surrounding whether allergy and hypersensitivity has a clinical basis for implant selection in total knee arthroplasty (TKA). In error, the terms hypersensitivity and allergy are often used synonymously. Although a relationship is present, we could not find any evidence of implant failure due to allergy. There is however increasing basic science that suggests a link between loosening and metal ion production. This is not an allergic response but is a potential problem. With a lack of evidence logically there can be no justification to use 'hypoallergenic' implants in patients who have pre-existing skin sensitivity to the metals used in TKA.

[Histopathological particle algorithm. Particle identification in the synovia and the SLIM]

BACKGROUND

In the histopathological diagnostics of synovitis and the synovium-like interface membrane (SLIM) the identification of crystals and crystal-like deposits and the associated inflammatory reactions play an important role. The multitude of endogenous crystals, the range of implant materials and material combinations, and the variability in the formation process of different particles explain the high morphological particle heterogeneity which complicates the diagnostic identification of diagnostic particles.

STUDY DESIGN AND METHODS

A simple histopathological particle algorithm has been designed which allows methodological particle identification based on (1) conventional transmitted light microscopy with a guide to particle size, shape and color, (2) optical polarization criteria and (3) enzyme histochemical properties (oil red staining and Prussian blue reaction). These methods, the importance for particle identification and the differential diagnostics from non-prosthetic materials are summarized in the so-called histopathological particle algorithm.

RESULTS

A total of 35 cases of synovitis and SLIM were analyzed and validated according to these criteria. Based on these criteria and a dichotomous differentiation the complete spectrum of particles in the SLIM and synovia can be defined histopathologically.

CONCLUSION

For histopathological diagnosis a particle score for synovitis and SLIM is recommended to evaluate (1) the predominant type of prothetic wear debris with differentiation between microparticles, and macroparticles, (2) the presence of non-prosthesis material particles and (3) the quantification of particle-association necrosis and lymphocytosis. An open, continuously updated web-based particle algorithm would be helpful to address the issue of particle heterogeneity and include all new particle materials generated in a rapidly changing field.

Clinical and diagnostic challenges of metal implant allergy using the example of orthopaedic surgical implants: Part 15 of the Series Molecular Allergology

The focus of this review are allergic reactions to orthopaedic-surgical metal implants. The spectrum of metal implant associated potential allergic reactions encompasses eczema, impaired wound and fracture healing, infection-mimicking reactions, effusions, pain and loosening. Nickel, cobalt and chromium seem to be the predominant eliciting allergens. Despite the growing number of respective publications the topic „metal implant allergy“ remains a diagnostic challenge. Initially, differential diagnoses should always be excluded in cooperation with surgery collegues. It is recommended to perform a combined evaluation of medical history, clinical findings, patch testing and histology. The lymphocyte transformation test (LTT) can indicate metal sensitization, but it needs careful interpretation. Allergists can provide a substantial contribution to this interdisciplinary topic.

Allergy or tolerance: reduced inflammatory cytokine response and concomitant IL-10 production of lymphocytes and monocytes in symptom-free titanium dental implant patients

Hypersensitivity reactions to titanium (Ti) are very rare. Thus, we assessed the proinflammatory response and also potential tolerance favoring in vitro reactivity of human blood lymphocytes and monocytes (PBMC) to Ti in healthy individuals (14 without, 6 with complication-free dental Ti implants). The proliferation index (SI) in lymphocyte transformation test (LTT) and production of cytokines linked to innate immune response (IL-1β, IL-6, and TNFα) or immune regulation (IL-10) were assessed in response to TiO₂ particles or Ti discs. In both groups, the Ti-LTT reactivity was not enhanced (e.g., SI < 3). The control antigen tetanus toxoid (TT) gave adequate reactivity (median SI individuals without/with implant: 20.6 ± 5.97/19.58 ± 2.99). Individuals without implant showed higher cytokine response to Ti materials than individuals with symptom-free implants; for example, TiO₂ rutile particle induced increase of IL-1β 70.27-fold/8.49-fold versus control medium culture. PBMC of 5 of the 6 individuals with complication-free Ti implants showed an ex vivo ongoing production of IL-10 (mean 4.18 ± 2.98 pg/mL)-but none of the 14 controls showed such IL-10 production. Thus in vitro IL-1β-, IL-6-, and TNF-α production reflects “normal” unspecific immune response to Ti. This might be reduced by production of tolerogenic IL-10 in individuals with symptom-free Ti dental implants.