Metal hypersensitivity testing in patients undergoing joint replacement: a systematic review

Long term follow-up of a completely metal free total knee endoprosthesis in comparison to an identical metal counterpart

Aseptic loosening is a feared and not yet fully-understood complication of total knee arthroplasty (TKA). Hypersensitivity reactions may be the underlying cause within some susceptible patients. Metal-free implants have been developed as a possible solution. The aim of this prospective, observational long-term study was the assessment of a completely metal-free ceramic knee replacement system compared to its identical metal counterpart 8 years after implantation, conducted as a follow-up of a previous report. A total of 88 patients (mean age 69 years) were enrolled in this prospective, observational long-term 8-year follow-up study. The "ceramic group" with a completely metal-free total knee replacement system was compared to the "conventional group" with an identical metal TKA system at the final follow-up. Clinical assessment included Knee Society Score (KSS), Oxford Knee Score (OKS), European Quality of Life 5 Dimensions 3 Level Version (EQ-5D-L), European Quality of Life 5 Dimension Visual Analogue Scale (EQ-VAS) and High Activity Arthroplasty Score (HAAS) as well as perioperative or postoperative complications and need for revision. The tibial/femoral positioning, signs of periprosthetic fissures/fractures or radiolucent lines were documented radiographically. All postoperative clinical scores in the ceramic group primarily improved from baseline to 4-year follow-up, but then decreased at the final 8-year follow-up. At the final follow-up, statistically non-significant differences were found in comparison of both groups for the KSS (ceramic: 166 ± 31, conventional: 162 ± 29; p > 0.05), OKS (ceramic: 37, conventional: 39; p > 0.05), EQ-VAS (ceramic: 77 ± 17, conventional: 72 ± 18; p > 0.05), and HAAS (ceramic: 8.29 ± 3.32, conventional: 9.28 ± 4.44; p > 0.05). A significant difference was found for EQ-5D-L (ceramic: 0.819 ± 0.284, conventional: 0.932 ± 0.126; p ≤ 0.05). Progressive radiolucent lines have been found around the uncemented tibial stem (0.8 mm at initial diagnosis (mean 19 months); 1.3 mm at 4-year follow-up; 1.6 mm at 8-year follow-up) without any clinical signs of loosening. One revision surgery was performed after a traumatic polyethylene inlay-breakage. No allergic reactions could be detected. The used ceramic TKA system meets the functional performance standards of an established identical metal TKA system after an 8-year follow-up period, offering a safe option for patients with prior hypersensitivity reactions to metallic materials. Full cementation of ceramic components is recommended.

Metal hypersensitivity in trapeziometacarpal arthroplasty: A systematic pattern of progression

Metal hypersensitivity is a rare and often underestimated complication, as shown by the small number of published studies, particularly concerning the upper limbs and the hand. However, the increase in the annual number of trapeziometacarpal arthroplasties underlines the importance of better understanding of this problem. We performed a study based on data from the revision of trapeziometacarpal prostheses to assess the incidence of this complication and to define a sequence of radiological changes to detect metal hypersensitivity. This single-center retrospective study included 37 patients operated on between January 2014 and November 2023 for revision of trapeziometacarpal prosthesis. Ten (27%) had no clearly identified cause of failure. For these 10 patients, we analyzed clinical data and postoperative X-rays. In the 11 revision arthroplasties, 2 patients had no symptoms or radiographic signs suggestive of allergy. Six patients had a-posteriori diagnosis established by allergy testing, which also identified 2 additional patients, for a total of 8 patients (21% of the initial cohort). In these cases, there was systematic metaphyseal osteolysis of the first metacarpal between 15 days and 1 month after implantation. Clinically, most patients had an asymptomatic period of 2 weeks to 1 month before onset of symptoms and osteolysis, often accompanied by local inflammation. This study found a reproducible pattern of progression, characterized by the appearance of radiographic signs of osteolysis in the first month, followed by clinical deterioration. Although this course is strongly suggestive of a metal hypersensitivity, it is crucial not to exclude the possibility of an infectious cause, which should always be considered.

Nickel allergy does not correlate with function after total knee arthroplasty

PURPOSE

The purpose of this study is to determine if there is a relationship between clinical outcomes and nickel allergy by evaluating asymptomatic total knee arthroplasty (TKA) patients with well-functioning implants through quantitative metal allergy (MA) testing.

METHODS

A prospective case series was performed on 50 patients with well-functioning TKA of various implant types. Inclusion criteria included primary TKA with a minimum 12-month follow-up and Oxford knee score (OKS) ≥ 40. A commercially available Lymphocyte Transformation Test measured the amount of a hypersensitivity lymphocyte immune response after exposure to a particular antigen. MA results were stratified based on the stimulation index (SI). The Cochran-Mantel-Haenzel test was used to test the homogeneity of metal reactivities. The Wilcoxon-Mann-Whitney test was used to compare individual metal SI by gender and the association of OKS and metal SI was ascertained with the Spearman correlation.

RESULTS

Nickel, cobalt, and chromium do not have the same reactivity scores (p < 0.001), and only nickel showed reactive/highly reactive scores. Females were found to have 3.41 times the odds of males for higher Ni reactivity (p = 0.0295, odds ratio [OR], 95% confidence interval [CI] = 3.41 [1.13-10.3]) only. Clinically, there was no correlation between metal SI and OKS score by metal (Ni rho = -0.1779; Co rho = -0.0036; Cr rho = -0.1748).

CONCLUSION

This is the first study looking at MA in well-functioning TKA. There is no correlation between clinical results and nickel reactivity. Surgeons should exercise caution when revising a painful or poorly functioning TKA based solely on a 'positive' Nickel Allergy test and look for other possible reasons for failure.

LEVEL OF EVIDENCE

Level II.

Existing and Novel Assessment Methods for Metal Sensitivity in Elective Lower-Limb Arthroplasty-A Scoping Review

Background

Metal sensitivity is a possible cause for revision in elective lower-limb arthroplasty. This scoping review aims to identify and evaluate all existing and novel assessment methods for metal sensitivity in elective lower-limb arthroplasty.

Methods

The Cochrane Central Register of Controlled Trials (CENTRAL), Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed, and Google Scholar databases were searched for studies published between January 1, 2000, and September 1, 2023. Studies evaluating one or more metal sensitivity assessment method preoperatively, perioperatively, or postoperatively were included. Studies were grouped based on the assessment methods reported and summarized based on the study design, outcome measure, results, and comments on the method's validity.

Results

A total of 1220 results were screened, with 39 results (15 retrospective cohort studies, 11 prospective cohort studies, 6 case reports, 5 randomized controlled trials, and 2 case control studies) included, identifying 12 assessment methods. The most used one was patch testing, featuring in 17 studies (43.6%). Lymphocyte transformation assay/testing featured in 12 studies (30.8%). Plasma/serum concentration of metal ions featured in 6 studies (15.4%). Patient history and serum cytokine testing featured in 7 (17.9%) and 4 (10.3%) studies each. Generalized serum inflammatory markers featured in 3 studies (7.7%). The remaining 6 methods each featured in one or 2 studies. Evidence of the reliability of most metrics was limited.

Conclusions

Several assessment methods were identified. However, evidence of any methods reliably predicting and diagnosing the occurrence of metal sensitivity was limited. There is a need for improved metrics of metal hypersensitivity.

A review on manufacturing processes of cobalt-chromium alloy implants and its impact on corrosion resistance and biocompatibility

Cobalt-Chromium (CoCr) alloys are currently used for various cardiovascular, orthopedic, fracture fixation, and dental implants. A variety of processes such as casting, forging, wrought processing, hot isostatic pressing, metal injection molding, milling, selective laser melting, and electron beam melting are used in the manufacture of CoCr alloy implants. The microstructure and precipitates (carbides, nitrides, carbonitrides, and intermetallic compounds) formed within the alloy are primarily determined by the type of manufacturing process employed. Although the effects of microstructure and precipitates on the physical and mechanical properties of CoCr alloys are well reviewed and documented in the literature, the effects on corrosion resistance and biocompatibility are not comprehensively reviewed. This article reviews the various processes used to manufacture CoCr alloy implants and discusses the effects of manufacturing processes on corrosion resistance and biocompatibility. This review concludes that the microstructure and precipitates formed in the alloy are unique to the manufacturing process employed and have a significant impact on the corrosion resistance and biocompatibility of CoCr alloys. Additionally, a historical and scientific overview of corrosion and biocompatibility for metallic implants is included in this review. Specifically, the failure of CoCr alloys when used in metal-on-metal bearing surfaces of total hip replacements is highlighted. It is recommended that the type of implant/application (orthopedic, dental, cardiovascular, etc.) should be the first and foremost factor to be considered when selecting biomaterials for medical device development.

Difficult Preoperative Diagnosis of Suspected Metal Hypersensitivity in a Case with Early Failure of Bipolar Hemiarthroplasty

Background

Metal hypersensitivity is a rare complication after total hip arthroplasty (THA), and no reliable diagnostic method for metal hypersensitivity to orthopedic metal implants has yet been established. Case report. A 57-year-old woman underwent hemiarthroplasty using a metal implant despite a skin allergy to metal jewelry. Two years after surgery, the patient developed early hemiarthroplasty failure and refractory erythema. Although the patient was clinically suspected to have a hypersensitivity to metal, the preoperative screening test was negative, and patient underwent revision surgery with cemented THA. Postoperatively, the erythema as well as her hip pain disappeared completely.

Conclusion

Patients with clinically suspected metal hypersensitivity should undergo primary and revision total hip arthroplasty using hypoallergenic implants regardless of preoperative screening results.

"Systematic review and meta-analysis of ceramic coated implants in total knee arthroplasty. Comparable mid-term results to uncoated implants."

BACKGROUND

Nitride-based ceramic coatings, such as titanium nitride (TiN) and titanium niobium nitride (TiNbN), have been introduced in total knee arthroplasty (TKA) to enhance the mechanical properties and biocompatibility of knee components, harden the metal surface and reduce CoCrMo exposure and metal ion release. However, the theoretical advantages of these ceramic coatings in TKA have yet to be fully elucidated. This systematic review aimed to provide clinical evidence on mid-term outcomes of ceramic-coated knee prostheses in comparison with uncoated standard CoCrMo knee prostheses in primary TKA. The hypothesis was that ceramic-coated implants can be used in primary TKA with no inferior outcomes compared to uncoated CoCrMo implants.

METHODS

A systematic review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to find all clinical studies regarding primary TKA with ceramic-coated knee prostheses. MEDLINE (PubMed), Embase and Cochrane Library were searched from 1990 to October 2020 to identify relevant studies for the first qualitative analysis. Using PICOS eligibility criteria, a subgroup of the selected studies was used to perform a meta-analysis.

RESULTS

Fifteen studies were included in this systematic review, of which six were included in the meta-analysis: 3 randomized controlled trials, 2 retrospective comparative studies and 1 prospective cross-sectional study. Pooled data overall included 321 coated TKAs vs. 359 uncoated TKAs and a mean follow-up of 4.6 years (range, 2-10 years). No significant difference in the implant survival risk ratio with revision or reoperation due to any reason was found between coated and uncoated TKAs, even considering the RCT study subgroup with a risk ratio of 1.02 (P = 0.34). No significant differences were found for postoperative complications, clinical scores, or metal blood concentrations at 1 year.

CONCLUSION

The findings of this systematic review and meta-analysis support the statement that ceramic-coated TKAs are not inferior to uncoated TKAs, showing comparable survival rates, complication rates and clinical outcomes. There is strong evidence that ceramic-coated TKA does not improve the clinical results or survival rate in comparison with uncoated TKA.

LEVEL OF EVIDENCE

II,  Therapeutic.

Metal reactivity is present in dogs with tibial plateau leveling osteotomy and total hip replacement implants

OBJECTIVE

Determine whether dogs with well-functioning orthopedic metal implants can develop metal reactivity.

SAMPLE

Client-owned dogs that had tibial plateau leveling osteotomy (TPLO) or total hip replacement (THR) implants for 12 months or more and control dogs with no implants.

PROCEDURES

Lymphocyte transformation testing was performed by exposing peripheral blood lymphocytes to nickel (Ni), chromium (Cr), cobalt (Co), or a combination of these metals. Lymphocyte proliferation was assessed with flow cytometry. Lymphocyte stimulation indexes (SIs) were calculated. A SI > 2 was considered reactive. Median SIs of dogs in response to metal exposure were compared statistically.

RESULTS

Samples from 10 dogs with TPLO, 12 dogs with THR, and 7 control dogs were analyzed. Six dogs out of 22 with metal implants had a reactive SI to 1 or more metals, while 2 of 7 control dogs had a SI > 2 when exposed to nickel only. When all metals were considered, no differences in metal reactivity were found between TPLO, THR, and control groups.

CLINICAL RELEVANCE

Metal reactivity is present in dogs and can be identified using lymphocyte transformation testing. Reactivity to Ni is present in dogs with and without metal implants. Reactivity to Co and Cr occurs in some dogs with metal implants.

Titanium niobium nitride knee implants are not inferior to chrome cobalt components for primary total knee arthroplasty at medium-term follow-up

BACKGROUND

Oxidized zirconium (Oxinium), titanium nitride (TiN) or titanium niobium nitride (TiNbN) coated implants became in recent years available for an increasing amount of total knee arthroplasty (TKA) systems. The hypothesis of this study was that the use of TiNbN-coated components would not lead to inferior results compared to conventional implants and that none of the metal hypersensitivity patients receiving TiNbN-coated implants would require revision for metal allergy.

MATERIALS AND METHODS

This retrospective study compared 53 Titanium Niobium Nitride coated TKA with 103 conventional chrome cobalt implants of the same design. Patients were evaluated at a minimal follow-up of 3 years.

RESULTS

No differences in clinical, radiological or patient-reported outcome measurements were observed between these groups. A survivorship of 96% without differences in revision rates was observed at medium-term follow-up of 6.5 years.

DISCUSSION

Metal allergy leading to contact or generalized dermatitis after TKA is very rare and usually linked to chrome or cobalt hypersensitivity. Nickel release from knee implants has not been shown to lead to cutaneous symptoms, but unexplained pain and swelling, peri-prosthetic osteolysis and component loosening remain potential issues not fully understood. The use of coated implants eliminates this factor from the diagnostic equation in case of postoperative dissatisfaction.

CONCLUSION

The use of titanium niobium nitride coated implants for primary knee osteoarthritis in self-reported metal hypersensitivity patients shows similar outcomes and survivorship rates as conventional chrome cobalt TKA, with no revisions for allergy at medium-term follow-up.

Allergy Testing Has No Correlation with Intraoperative Histopathology from Revision Total Knee Arthroplasty for Implant-Related Metal Allergy

Lymphocyte transformation testing (LTT) is often used in the workup for possible metal allergy after total knee arthroplasty (TKA) but the correlation of this test with other diagnostic metal-allergy findings in patients undergoing revision TKA for suspected metal allergy has not been established. A single-center, single-surgeon cohort of 19 TKAs in which both components were revised for presumed implant-related metal allergy based on history, physical, and LTT testing, to nonnickel-containing implants were retrospectively identified. Histopathologic samples obtained intraoperatively were semiquantitatively analyzed using both the Hospital for Special Surgery (HSS) synovial pathology score and the Campbell aseptic lymphocyte-dominant vasculitis-associated lesion (ALVAL) score. As histopathology control group, we included in the study an additional cohort of 17 patients who received aseptic revision TKA and had no history of reported or tested metal sensitivity. All preoperative LTT results were highly reactive to nickel. However, this did not correlate with local periarticular tissue response in 18 of 19 cases which demonstrated a low HSS synovial score (mean: 3.8 ± 2.8, of a maximum score of 28) and the low Campbell ALVAL scores (mean: 2.5/10 ± 1.3, of a maximum score of 10). There were not any significant differences between the study group (suspected implant-related metal allergy) and the control group (nonsuspected implant-related metal allergy) in regard to (1) the Campbell score and (2) the HSS synovial inflammatory score. Knee Society Clinical Rating System (KSCRS) function score improved significantly after revision (mean postoperative increase: 34.0 ± 17. 2; p < 0.001), as well as mean visual analog scale (VAS) pain (mean postoperative decrease: 33.3 ± 26.4; p < 0.01) score. The short-term survival rate (at mean follow-up of 26.1 months) of this patient cohort was 100%. In this cohort of revised TKA patients with suspected nickel allergy based on clinical presentation and LTT positive results, intraoperative histopathology was essentially normal. However, all patients with suspected nickel allergy showed a significant clinical and functional improvement with excellent short-term survival rates. The clinical significance of a positive LTT needs further study.

Lymphocyte transformation test reveals low prevalence of true metal hypersensitivity among pre-operative total knee arthroplasty patients

PURPOSE

The aims of this study were to determine the prevalence of metal hypersensitivity, and identify pre-operative factors which could predict susceptibility to hypersensitivity reactions among patients scheduled for primary total knee arthroplasty (TKA). The present study used a testing method consistent with the recognised biological response to metals.

METHODS

A prospective cross-sectional analysis of 220 patients was conducted. All patients received a testing protocol using lymphocyte transformation test to evaluate reactivity to possible contents of orthopaedic implants. Test response is interpreted as stimulation index (SI) values. A comprehensive questionnaire was used to evaluate prior exposure. Patients were categorised according to SI values and the odds ratios (OR) were calculated as comparative effect measure for each predetermined prior exposure factor.

RESULTS

The prevalence of metal sensitivity response was 28% (n = 61) among patients with susceptibility to at least one agent (SI = 2 to 4.9), and 3.2% (n = 7) among patients with true hypersensitivity (SI ≥ 5). The population-weighted prevalence, adjusted for sampling weights of symptomatic knee osteoarthritis, was SI ≥ 5 = 4.7% (95% CI 0.4-11.8%) and SI ≥ 2 = 35.2% (95% CI 24.8-48.6%). Stimulation index levels of response to materials were markedly varied with the highest being aluminium. Female sex, smoking history, cutaneous reaction to jewellery, occupational exposure, and dental procedures were among factors shown to increase the odds of having higher reactivity response to tested metals. Nevertheless, patients with well-functioning prior contralateral TKA did not appear at greater risk of having either sensitivity or susceptibility with odds ratio (OR) = 0.2 (95% CI 0.01-3.2), p: NS and OR = 0.6 (95% CI 0.3-1.2), p: NS, respectively. Prior positive patch test was neither predictor of susceptibility to hypersensitivity OR = 1.2 (95% CI 0.6-2.6) p: NS nor predictor of true hypersensitivity OR = 0.7 (95% CI 0.08-6.1), p: NS.

CONCLUSION

Among patients scheduled for primary TKA with no prior clinical features of metal allergy the prevalence of true hypersensitivity to at least one metal is just over 3%. Patients are likely to encounter a material to which they have pre-existing susceptibility to hypersensitivity. With certain prior exposure factors, there was increased susceptibility to metal hypersensitivity reaction evoking an acquired condition.

LEVEL OF EVIDENCE

Level II, prospective cross-sectional study.

Characterization of the Toxicological Impact of Heavy Metals on Human Health in Conjunction with Modern Analytical Methods

Increased environmental pollution, urbanization, and a wide variety of anthropogenic activities have led to the release of toxic pollutants into the environment, including heavy metals (HMs). It has been found that increasing concentrations of HMs lead to toxicity, mineral imbalances, and serious diseases, which are occurring more and more frequently. Therefore, testing has become imperative to detect these deficiencies in a timely manner. The detection of traces of HMs, especially toxic ones, in human tissues, various biological fluids, or hair is a complex, high-precision analysis that enables early diagnosis, addressing people under constant stress or exposed to a toxic environment; the test also targets people who have died in suspicious circumstances. Tissue mineral analysis (TMA) determines the concentration of toxic minerals/metals at the intracellular level and can therefore determine correlations between measured concentrations and imbalances in the body. Framing the already-published information on the topic, this review aimed to explore the toxicity of HMs to human health, the harmful effects of their accumulation, the advantages vs. the disadvantages of choosing different biological fluids/tissues/organs necessary for the quantitative measurement of HM in the human body, as well as the choice of the optimal method, correlated with the purpose of the analysis.

The effect of Nickel hypersensitivity on the outcome of total knee arthroplasty and the value of skin patch testing: a systematic review

Background

To assess the Nickel sensitizing potential of total knee arthroplasty (TKA), explore the relationship between hypersensitivity and clinical outcomes, and evaluate the utility of skin patch testing pre- and/or postoperatively.

Materials and methods

A literature search was performed through EMBASE, Medline and PubMed databases. Articles were screened independently by two investigators. The level of evidence of studies was assessed using the Oxford Centre for Evidence-Based Medicine Criteria and the quality evaluated using the Methodological Index for Non-randomized Studies and Cochrane risk-of-bias tools.

Results

Twenty studies met the eligibility criteria, reporting on 1354 knee arthroplasties. Studies included patients undergoing primary or revision TKA, pre- and/or postoperatively, and used patch testing to identify Nickel hypersensitivity. Prevalence of Nickel hypersensitivity ranged from 0% to 87.5%. One study compared the prevalence of Nickel hypersensitivity in the same patient group before and after surgery and noted newly positive patch test reactions in three patients (4.2%). Three studies reported lower prevalence of Nickel hypersensitivity in postoperative patients compared to preoperative ones. Seven studies suggested that hypersensitivity might cause adverse clinical outcomes, but six did not support any relationship. Seven studies recommended preoperative patch testing in patients with history of metal allergy, and nine concluded that testing may be valuable postoperatively.

Conclusions

Patients undergoing TKA with no prior history of metal hypersensitivity do not seem to be at an increased risk of developing Nickel hypersensitivity, and there is conflicting evidence that patients with pre-existing hypersensitivity are more likely to experience adverse outcomes. Patch testing remains the most commonly used method for diagnosing hypersensitivity, and evidence suggests preoperative testing in patients with history of metal allergy to aid prosthesis selection, and postoperatively in patients with suspected hypersensitivity once common causes of implant failure have been excluded, since revision with hypoallergenic implants may alleviate symptoms.

Lymphocyte Subset Ratio Cannot Diagnose Immune Failure of a TKA

BACKGROUND

Up to 20% of patients are dissatisfied following total knee arthroplasty (TKA), most often due to pain and/or stiffness. The differential diagnosis includes immune reaction to the prosthesis. However, there is no consensus on diagnostic criteria for immune failure, an allergic reaction, to a TKA. Histologic evaluation could provide evidence as to whether an allergic reaction caused TKA failure. A recent study showed an increase in CD4+ lymphocytes compared to CD8+ lymphocytes in patients lymphocyte transformation testing (LTT) + for Ni. This finding is consistent with Ni sensitization, but can lymphocyte subsets be used to diagnose immune failure on a case-by-case basis?

METHODS

Periprosthetic tissues from 18 revision cases of well-fixed, aseptic, but painful and/or stiff primary TKAs were analyzed. Six patients LTT- for Ni were matched as a cohort for age, sex, and body mass index (BMI), to 12 patients LTT + for Ni. Periprosthetic tissue biopsies underwent immunohistochemical IHC staining for CD4+ and CD8+ lymphocyte subsets and were compared by LTT status. The immunohistochemicalIHC results were also compared with periprosthetic histology.

RESULTS

There was no relationship between LTT status and mean CD4+ cells/hpf or CD4+:CD8+ lymphocyte ratio. No relationship was found between LTT stimulation index (continuous or categorical) and CD4+:CD8+ ratio or aseptic lymphocyte-dominant vasculitis-associated lesion ALVAL score.

CONCLUSION

Lymphocytes in periprosthetic tissue are highly variable in number, subtype ratio, and location, and have no relationship to LTT result or ALVAL score on a case-by-case basis. Based on these results, lymphocyte subsets cannot diagnose immune failure. Further work is needed to determine criteria for the diagnosis of immune failure of a TKA.

Evaluation of local tissue peri-implant reaction in total knee arthroplasty failure cases

Introduction:

Implant-related hypersensitivity is emerging as a causative factor as a potential source of total knee arthroplasty (TKA) failure. Mechanistically, this type IV hypersensitivity reaction (T4HR) is mediated by effector T-cells, macrophages, and leukocytes that infiltrate to the site of implant and react to metal exposure and induce inflammatory tissue damage.

Methods:

A case–control study was performed where cortical bone was taken at the time of revision surgery for all patients operated on for primary TKA in which metal allergy was suspected and for revision TKA cases done for presumed metal allergy. Cytof was used to determine the cell density of inflammatory cells, specifically Th1, Th2, M1, and M2 cells.

Results:

Comparing the mean cell density of primary versus revision TKA, revision TKA patients had significantly higher number of Th2 cells compared with Th1 cells ( p = 0.0043). Among revision cases, there were significantly more M1 versus M2 macrophages ( p = 0.034) within a patient. When comparing mean cell density of M1 versus M2 macrophages, there was a significant difference in both primary and revision TKA surgeries ( p = 0.0041 primary, p < 0.001 revision). Among revision patients who had a predominance of Th2 cells, four (44%) of nine patients had a negative LTT/patch test.

Conclusion:

These data support metal hypersensitivity, mediated by a T4HR, for some cases of TKA failure. Current methods to screen patients for metal hypersensitivity prior to primary TKA have been inclusive. This study demonstrates the need for a more sensitive screening test from specimens in the knee joint, to more accurately identify patients who will exhibit a T4HR to metal.

Impact of Preoperative Metal Patch Testing on Surgery Using Metal Implants

Background

Patients scheduled for metal implant surgery in some facilities in Japan undergo preoperative metal patch testing (MPT). However, few studies have reported the impact of MPT results on scheduled surgery; therefore, the value of preoperative MPT remains unknown.

Material and methods

In analysis 1,the preoperative MPT results requested by orthopedic surgeons from 4 institutions from 2014 to 2018 were retrospectively analyzed. In analysis 2, the medical records of all patients who underwent total hip arthroplasty, total knee arthroplasty, or total shoulder arthroplasty/reverse shoulder arthroplasty between 2014 and 2018 were collected. The number of patients who underwent MPT and their surgical results were analyzed.

Results

In analysis 1, MPT was performed on 72 patients during the study period. The overall MPT positivity rate was 26.4% for the entire cohort in analysis 1. In 4 out of 19 MPT-positive cases, the results of MPT changed the treatment plan to use alternative materials or cancel the surgery. In analysis 2, 1087 patients underwent total hip arthroplasty, total knee arthroplasty, and TSA/RSA; only 16 patients underwent MPT. Aseptic loosening occurred postoperatively in 3 patients (0.3%), none of whom had a history of allergy, and none underwent preoperative MPT.

Conclusion

Metal allergy did not appear to be directly involved in aseptic loosening to any large or meaningful degree in our patient cohort. Only 1.5% of the patients underwent preoperative MPT; therefore, our results suggest this testing had limited benefit or utility. Further studies are needed to determine whether MPT is necessary in preparation for joint replacement.

Perivascular lymphocytic aggregates in hip prosthesis-associated adverse local tissue reactions demonstrate Th1 and Th2 activity and exhausted CD8+ cell responses

Hip implants are a successful solution for osteoarthritis; however, some individuals with metal-on-metal (MoM) and metal-on-polyethylene (MoP) prosthetics develop adverse local tissue reactions (ALTRs). While MoM and MoP ALTRs are presumed to be delayed hypersensitivity reactions to corrosion products, MoM- and MoP-associated ALTRs present with different histological characteristics. We compared MoM- and MoP-associated ALTRs histopathology with cobalt and chromium levels in serum and synovial fluid. We analyzed the gene expression levels of leukocyte aggregates and synovial fluid chemokines/cytokines to resolve potential pathophysiologic differences. In addition, we classified ALTRs from 79 patients according to their leukocyte infiltrates as macrophage-dominant, mixed, and lymphocyte-dominant. Immune-related transcript profiles from lymphocyte-dominant MoM- and MoP-associated ALTR patients with perivascular lymphocytic aggregates were similar. Cell signatures indicated predominantly macrophage, Th1 and Th2 lymphocytic infiltrate, with strong exhausted CD8⁺ signature, and low Th17 and B cell, relative to healthy lymph nodes. Lymphocyte-dominant ALTR-associated synovial fluid contained higher levels of induced protein 10 (IP-10), interleukin-1 receptor antagonist (IL-1RN), IL-8, IL-6, IL-16, macrophage inflammatory protein 1 (MIP-1α), IL-18, MCP-2, and lower cell-attracting chemokine levels, when compared with prosthetic revisions lacking ALTRs. In addition, the higher levels of IP-10, IL-8, IL-6, MIP-1α, and MCP-2 were observed within the synovial fluid of the lymphocyte-dominant ALTRs relative to the macrophage-dominant ALTRs. Not all cytokines/chemokines were detected in the perivascular aggregate transcripts, suggesting the existence of other sources in the affected synovia. Our results support the hypothesis of common hypersensitivity pathogenesis in lymphocyte-dominant MoM and MoP ALTRs. The exhausted lymphocyte signature indicates chronic processes and an impaired immune response, although the cause of the persistent T-cell activation remains unclear. The cytokine/chemokine signature of lymphocyte-dominant-associated ATLRs may be of utility for diagnosing this more aggressive pathogenesis.

Aseptic and septic prosthetic joint loosening: Impact of biomaterial wear on immune cell function, inflammation, and infection

The success of total joint replacements has led to consistent growth in the use of arthroplasty in progressively younger patients. However, more than 10 percent of patients require revision surgeries due to implant failure caused by osteolytic loosening. These failures are classified as either aseptic or septic and are associated with the presence of particulate wear debris generated by mechanical action between implant components. Aseptic loosening results from chronic inflammation caused by activation of resident immune cells in contact with implant wear debris. In contrast, septic loosening is defined by the presence of chronic infection at the implant site. However, recent findings suggest that subclinical biofilms may be overlooked when evaluating the cause of implant failure, leading to a misdiagnosis of aseptic loosening. Many of the inflammatory pathways contributing to periprosthetic joint infections are also involved in bone remodeling and resorption. In particular, wear debris is increasingly implicated in the inhibition of the innate and adaptive immune response to resolve an infection or prevent hematogenous spread. This review examines the interconnectivity of wear particle- and infection-associated mechanisms of implant loosening, as well as biomaterials-based strategies to combat infection-related osteolysis.

No Clinical or Radiographic Differences Between Cemented Cobalt-Chromium and Titanium-Niobium Nitride Mobile-Bearing Unicompartmental Knee Arthroplasty

PURPOSE

This study aimed to compare the clinical and radiographic outcomes of patients with positive patch tests undergoing a medial mobile-bearing titanium-niobium nitride (TiNbN) unicompartmental knee arthroplasty (UKA) to patients undergoing standard UKA (cobalt-chromium [CoCr] implants).

METHODS

Two successive groups of patients, amounting to a total of 246 individuals, who received Oxford (Zimmer-Biomet, Warsaw, Indiana, USA) UKA were included. The first group was composed of a series of 203 consecutive standard CoCr UKAs (Standard Group), while the second group comprised 43 consecutive hypoallergenic TiNbN UKAs (HA group). The patients of the second group had a positive epicutaneous patch test result for metals. Each patient was evaluated using the Oxford Knee Score (OKS) and Knee Society Score (KSS) a day prior to the surgery (T ₀) and at two consecutive follow-ups, namely T ₁ (minimum follow-up of 12 months) and T ₂ (minimum follow-up of 34 months). Radiographic measurements were performed at the final follow-up (T ₂).

RESULTS

No statistical differences were noted between the two groups regarding demographic data (p > 0.05). No clinical or radiographic differences were found between the HA and standard groups at any follow-up (p > 0.05). A statistically significant improvement was found at any follow-up for both OKS and KSS (p < 0.05).

CONCLUSIONS

No clinical or radiographic differences between the hypoallergenic and standard cobalt-chromium groups at any follow-up were found, with a clinically significant improvement being experienced by both groups during the entire follow-up.

LEVEL OF EVIDENCE

Level II-comparative prospective study.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00486-3.

Metal Hypersensitivity and Complex Regional Pain Syndrome After Bilateral Total Knee Arthroplasty: A Case Report

CASE

A 38-year-old man underwent bilateral total knee arthroplasty (TKA) and subsequently developed diffuse pain, swelling, and an eczematous rash that spread throughout his body. Despite various pharmacological regimens, sympathetic blocks, aggressive physical therapy, and further knee revisions, the patient's symptoms progressed over a period of 2 years. An in vitro memory lymphocyte immuno-stimulation assay test demonstrated reactivity to nickel after which bilateral revision TKAs with oxidized zirconium alloys resulted in symptomatic improvement.

CONCLUSION

Metal hypersensitivity should be considered after the exclusion of infection; however, the concurrent development of complex regional pain syndrome may mask the clinical presentation.

Periprosthetic Tissue Reaction Independent of LTT Result and Implanted Materials in Total Knee Arthroplasty

BACKGROUND

An allergic reaction may rarely cause a painful or stiff total knee arthroplasty (TKA). However, no consensus diagnostic criteria for TKA immune failure exist. Lymphocyte transformation testing (LTT) measures immune sensitivity to various materials, but its role in diagnosing an allergic reaction to a TKA has not been established. This study compares TKA periprosthetic tissues in a) LTT-positive versus -negative patients and b) patients with conventional CoCrNi versus hypoallergenic implants.

METHODS

Periprosthetic tissues from 26 revision cases of well-fixed, aseptic, but painful or stiff TKAs were analyzed. Twelve patients LTT positive for nickel (Ni) were matched as a cohort to 6 LTT-negative patients. In 4 patients LTT positive for Ni, tissue from first revision of CoCrNi implants was compared with tissue from subsequent revision of hypoallergenic implants. Histology was evaluated using the aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) score.

RESULTS

No correlation was found between LTT and any ALVAL score component. The mean total ALVAL score was 3.8 ± 1.5 for LTT-negative patients and 3.3 ± 1.2 for LTT-positive patients (P = .44). The mean total ALVAL score at revision of CoCrNi implants was 3.0 ± 1.8 compared with 5.8 ± 0.5 at rerevision of hypoallergenic implants (P = .053).

CONCLUSION

Periprosthetic TKA tissue reactions were indistinguishable between LTT-positive and -negative patients. LTT does not predict the periprosthetic tissue response. ALVAL scores of hypoallergenic revision implant tissue trended higher than primary CoCrNi implant tissue. A positive LTT may not indicate that a periprosthetic immune reaction is the cause of pain and stiffness after TKA.

LEVEL OF EVIDENCE

3, retrospective cohort study.

Impact of perivascular lymphocytic infiltration in aseptic total knee revision

AIMS

A limited number of investigations with conflicting results have described perivascular lymphocytic infiltration (PVLI) in the setting of total knee arthroplasty (TKA). The purpose of this study was to determine if PVLI found in TKAs at the time of aseptic revision surgery was associated with worse clinical outcomes and survivorship.

METHODS

A retrospective review was conducted on 617 patients who underwent aseptic TKA revision who had histological analysis for PVLI at the time of surgery. Clinical and radiological data were obtained pre- and postoperatively, six weeks postoperatively, and then every year thereafter.

RESULTS

Within this cohort, 118 patients (19.1%) were found to have PVLI on histological analysis. Re-revision was performed on 83 patients (13.4%) with no significant differences in all-cause or aseptic revisions between groups. A higher incidence of PVLI was noted in female patients (p = 0.037). There was no significant difference in improvement in the range of motion (p = 0.536), or improvement of KSC (p = 0.66), KSP (p = 0.61), or KSF (p = 0.3) clinical outcome scores between PVLI and no PVLI sub-groups. There was a higher incidence of a preoperative diagnosis of pain in the PVLI group compared with patients without PVLI (p = 0.002) present.

CONCLUSION

PVLI found on large-scale histological analysis in TKAs at aseptic revision surgery was not associated with worse clinical outcomes or rates of re-revision. Cite this article: Bone Joint J 2021;103-B(6 Supple A):145-149.

Sensitization to Implant Components Is Associated with Joint Replacement Failure: Identification and Revision to Nonallergenic Hardware Improves Outcomes

BACKGROUND

Over 90% of one million annual US joint replacements are highly successful. Nonetheless, 10% do poorly owing to infection or mechanical issues. Many implant components are sensitizers, and sensitization could also contribute to implant failure.

OBJECTIVE

To determine the prevalence of implant sensitization in joint failure patients, their clinical characteristics, and implant revision outcomes. We hypothesized that sensitized patients would improve when revised with nonallergenic materials.

METHODS

We prospectively enrolled 105 joint failure patients referred by orthopedic surgeons who had already excluded infection or mechanical causes. Patients provided informed consent, completed a history and physical examination, patch testing to metals and bone cement, and a nickel lymphocyte proliferation test. A study coordinator was able to contact 64% of patients (n = 67) 9 to 12 months later to evaluate outcomes.

RESULTS

A total of 59% were sensitized to an implant component: 32% to metal and 37% to bone cement. The nickel lymphocyte proliferation test was 60% sensitive and 96% specific in diagnosing nickel sensitization. Most sensitized subjects reported no or uncertain histories of reactions to a specific material. Implant sensitized patients were younger and reported previous eczema, joint itching, and implant loosening. By 9 to 12 months later, most patients with a revised implant (revised) described significant improvement (16 of 22 revised for sensitization [P = .0003] vs 9 of 13 revised without sensitization [P = .047]) compared with patients without implant revision). All revised patients with sensitization used components to which they were not sensitized. Pain (P = .001), swelling (P = .035), and instability (P = .006) were significantly reduced in the revised sensitized group.

CONCLUSIONS

Sensitization to implant components is an important cause of unexplained joint replacement failure. Joint revisions based on sensitization information resulted in significant improvements.

Metal Hypersensitivity in Joint Arthroplasty

Metal hypersensitivity in joint arthroplasty is a very controversial topic with limited evidence. With increasing numbers of joint replacements being done annually, a clear understanding of the pathogenesis, clinical picture, preimplant screening, postimplant workup, and treatment plan is crucial. This review article looked at all the available evidence regarding metal hypersensitivity and summarized the key findings. An algorithm was also proposed for preimplant screening, postimplant workup, and management.

The role of metal patch testing in evaluating patients for metallic prosthetic joint failure

BACKGROUND

Metal allergy may be an uncommon cause of prosthetic joint failure. There exist little data on patch testing to metals in this context and its impact on outcomes of joint revision in these patients.

OBJECTIVE

To explore the use and indications for metal patch testing in the evaluation of patients suspected of having metal allergy as a cause of failed joint replacements and to clarify the outcomes of patients revised with alternative metallic joints because of positive patch testing result.

METHODS

A retrospective analysis from January 2016 to April 2020 was completed on a patient cohort referred for evaluation of metal hypersensitivity. Charts were reviewed for age, biological sex, referring specialty, patch testing results, joint, revision status, and outcome measures. Biostatistical analysis and descriptive statistics were performed to determine patch testing performance and functional outcome trends among this patient cohort.

RESULTS

The sensitivity and specificity of patch testing, in general, are limited when evaluating patients with metallic joint replacements. However, the predictive value of testing seemed to improve with strongly positive patch testing results. Functional outcomes in patients when positive results were used to guide revision prosthesis revealed clinical improvement.

CONCLUSION

The attribution of metal allergy or hypersensitivity as a cause of failure in metal prosthetic joint replacement remains unproven. Some patients with positive histories and patch testing results that were used to modify the implanted prosthesis had improved functional outcomes. These results suggest that patch testing may be useful in patients with history of metal sensitivity and prosthetic failure.

Suspected Metal Allergy and Femoral Loosening After Total Knee Arthroplasty: A Diagnostic Dilemma

Metal sensitivity is increasingly prevalent and is associated with negative outcomes after total knee arthroplasty (TKA). Currently, there is no consensus on diagnostic criteria for TKA failure from immune reaction. We present a patient who had pain and aseptic effusion 2 years after TKA. Radiographs were concerning femoral loosening. Lymphocyte transformation testing showed nickel sensitivity. During revision surgery, the femoral component was loose. The histologic aseptic lymphocyte-dominated vasculitis-associated lesion score was 4 with elevated CD4+ lymphocytes, consistent with sensitization. Nickel-free revision implants were used. One year after surgery, the patient is symptom-free. This case has features suggestive of an immune reaction, with femoral loosening, and is illustrative of the diagnostic dilemma. Using a hypoallergenic knee eliminates future concern for nickel sensitivity.

Allergic Dermatitis Following Bilateral Oxidized Zirconium Total Knee Replacements

Introduction:

Total knee replacement (TKR) utilization is expected to increase by 673% in 2030, with patients between the ages of 45 to and 64 years representing the fastest-growingfastest growing age group requiring joint replacement. This group not only demands a higher- performinghigher performing, durable prosthesis but are is also the most likely to be dissatisfied if their expectations are not met. Hypo-allergenic implants have been developed by some implant manufacturers to fill this need, so the occurrence of allergic skin reactions after surgery is unanticipated and can have unwanted consequences if not recognized and managed appropriately.

Case Report:

We present the case of a 55-year-old woman who underwent bilateral staged TKR using oxidized zirconium implants and subsequently developed eczematous skin reactions. In both instances, she presented with a peri-incisional erythematous blistering skin reaction that was successfully treated with topical corticosteroids. Investigations revealed no evidence of infection or allergic-typeallergic type reactions to the metals contained in the knee replacements.

Conclusion:

Allergic skin reactions following TKR are very rare, and are not necessarily due to a metal hypersensitivity. Infection must be excluded in all cases and a trial of topical corticosteroids is useful before prior to more aggressive treatment, with the removal of the implant reserved as a last resort. To the best of our knowledge, this is the first case in the literature that reports the occurrence of allergic skin reactions following oxidized zirconium TKRs, and highlights the fact that allergic skin reactions can occur when using hypo-allergenic implants. Surgeons should be aware of this possibility and counsel their patients appropriately during the informed consent process.

Morbidity After Metal Allergy to a Total Ankle Implant

Metal allergy to total ankle arthroplasty is rare but can be both an unpredictable and devastating complication. Current literature describing metal allergy in orthopaedics is limited with there being no report to date on metal allergy after total ankle arthroplasty. Our patient underwent a total ankle arthroplasty and developed a diffuse rash 7 weeks postoperatively. The patient then tested positive for a metal allergy and ultimately was converted to an arthrodesis. In the setting of postoperative pain, swelling, erythema, or rash, it is important that metal allergy be on the differential diagnosis. Interestingly, when the patient here underwent allergy testing, only the articulating sides of the implant caused a positive reaction. Thus, allergy testing of both the articular and nonarticular sides of the component is of the utmost importance, as evidenced by the discrepancy found in this case.Levels of Evidence: Level IV: Case report.

The Biomaterials of Total Shoulder Arthroplasty: Their Features, Function, and Effect on Outcomes

The materials that are used in total shoulder arthroplasty (TSA) implants have been carefully chosen in an attempt to minimize hardware-related complications. The 2 main metal alloys used in TSA implants are Ti-6Al-4V (titanium-aluminum-vanadium) and CoCrMo (cobalt-chromium-molybdenum). Ti alloys are softer than CoCr alloys, making them less wear-resistant and more susceptible to damage, but they have improved osseointegration and osteoconduction properties. Although controversial, metal allergy may be a concern in patients undergoing TSA and may lead to local tissue reaction and aseptic loosening. Numerous modifications to polyethylene, including cross-linking, minimizing oxidation, and vitamin E impregnation, have been developed to minimize wear and reduce complications. Alternative bearing surfaces such as ceramic and pyrolytic carbon, which have strong track records in other fields, represent promising possibilities to enhance the strength and the durability of TSA prostheses.

Early Outcomes of an Alternative Bearing Surface in Primary Total Knee Arthroplasty in Patients with Self-reported Metal Allergy

Background

Most implants for total knee arthroplasty (TKA) are comprised of alloys that contain nickel. Controversy exists whether metal allergies produce negative effects and affect clinical outcomes. The purpose of this study was to retrospectively review a minimum 2-year follow-up with an ion-bombarded titanium TKA implant in patients with reported metal sensitivity.

Methods

A retrospective review of patients who underwent primary TKA with the ion-bombarded titanium Vanguard (Zimmer Biomet, Warsaw, IN) implant with 2-year minimum follow-up was performed from 2008 through 2017. The query revealed 346 patients (451 knees) with minimum 2-year follow-up. The mean age was 64.7 years, the mean body mass index was 35.1 kg/m², and 95% of patients were women.

Results

The mean follow-up was 4.6 years. The mean range of motion improved from 109° to 112° (P = .03), University of California Los Angeles activity scale from 4.1 to 5.1 (P < .001), Knee Society Clinical scores from 36 to 89 (P < .001), and Knee Society Functional scores from 48 to 73 (P < .001). There were 5 (1.1%) revisions: 2 infections (2-staged exchange), 1 tibial revision for aseptic loosening after a fall, and 2 bearing exchanges for instability. Other surgeries were open reduction internal fixation of periprosthetic fracture, 1 arthroscopic release of snapping popliteus, and 4 local wound incision and debridement (2 superficial infections and 2 nonhealing wounds). Manipulation under anesthesia was required in 27 (6%) patients.

Conclusions

These early results are encouraging for the use of alternative metal titanium alloy implants in metal-sensitive patients undergoing primary TKA. At 4.6 years of mean follow-up, patients had substantial improvement in the range of motion and clinical outcomes with a low frequency of revision.

Osteolysis after cervical disc arthroplasty

PURPOSE

Cervical disc arthroplasty (CDA) has become an increasingly popular treatment for cervical degenerative disc disease. One potential complication is osteolysis. However, current literature on this topic appears limited. The purpose of this study is to elucidate the incidence, aetiology, consequence, and subsequent treatment of this complication.

METHODS

A systematic literature review was performed according to the PRISMA guidelines. Studies discussing the causes, incidence and management of osteolysis after a CA were included.

RESULTS

A total of nine studies were included. We divided these studies into two groups: (1) large case series in which an active radiological evaluation for osteolysis was performed (total = six studies), (2) case report studies, which discussed symptomatic cases of osteolysis (total = three). The incidence of asymptomatic osteolysis ranged from 8 to 64%; however, only one study reported an incidence of < 10% and when this case was excluded the incidence ranged from 44 to 64%. Severe asymptomatic bone loss (exposure of the implant) was found in less than 4% of patients. Bone loss from osteolysis appeared to occur early (< 1 year) after surgery and late (> 1 year) as well. Symptomatic patients with osteolysis often required revision surgery. These patients required removal of implant and conversion to fusion in the majority of the cases.

CONCLUSIONS

Osteolysis after CDA is common; however, the majority of cases have only mild or asymptomatic presentations that do not require revision surgery. The timing of osteolysis varies significantly. This may be due to differences in the aetiology of osteolysis.

Nickel allergy to orthopaedic implants: A review and case series

Many of the metals used in orthopaedic surgical implants are immunologically active and can cause hypersensitivity reactions. Most of these metal hypersensitivity (MHS) reactions are type IV/delayed-type hypersensitivity reactions. The most common form of all metal hypersensitivity reactions is allergic contact dermatitis (ACD) caused by nickel. The purpose of this review is to examine the evidence regarding hypersensitivity to orthopaedic implants and provide current recommendations for evaluating these patients. We report on four case examples of patients where it was determined that metal allergy led to complications related to surgery. The most common symptoms for patients with MHS-associated failures are localized soft tissue reaction including delayed wound healing and/or recurrent wound issues. The best way to avoid postoperative issues is to routinely ask patients prior to surgery if they have any known MHS including problems with cosmetic jewelry. If this is known before surgery, titanium or carbon fiber implants should be used for fracture fixation and arthroplasty implantation choice should be modified based on the specific arthroplasty performed. MHS-associated failures are a diagnosis of exclusion and must be contemplated after judicious workup of localized soft tissue reaction including delayed wound healing and/or recurrent wound issues.

Cross-Reactivity of Palladium in a Murine Model of Metal-Induced Allergic Contact Dermatitis

Metal allergy is usually diagnosed by patch testing, however, the results do not necessarily reflect the clinical symptoms because of cross-reactivity between different metals. In this study, we established the novel mouse model of cross-reactive metal allergy, and aimed to elucidate the immune response in terms of T-cell receptor repertoire. This model was classified into two groups: the sensitization to nickel and challenge with palladium group, and the sensitization to chromium and challenge with palladium group. This model developed spongiotic edema with intra- and peri-epithelial infiltration of CD4⁺ T cells in the inflamed skin that resembles human contact dermatitis. Using T cell receptor analysis, we detected a high proportion of T cells bearing Trav8d-1-Traj49 and Trav5-1-Traj37 in the Ni- and Cr-sensitized Pd-challenged mice. Furthermore, mucosal-associated invariant T cells and invariant natural killer T cells were also detected. Our results indicated that T cells bearing Trav8d-1-Traj49 and Trav5-1-Traj37 induced the development of palladium-cross reactive allergy, and that mucosal-associated invariant T and invariant natural killer T cells were also involved in the cross-reactivity between different metals.

A Mid- to Long-Term Follow-Up Experience with a Specific Metal-on-Metal Total Hip Arthroplasty Design

Purrpose  Metal-on-metal (MoM) total hip arthroplasty (THA) has been a subject of recent discussion and concern due to the early failures caused by local and systemic adverse reactions related to specific designs. The aim of this study is to analyze the outcomes and survival rates of a single brand of MoM implants implanted in a consecutive series of patients at a single institution.

Methods  Between 2007 and 2012, 116 (118 hips) patients were evaluated at a mean follow-up of 6.6 years after primary THA. The diagnosis leading to surgery was osteoarthritis (80 patients) and proximal femoral fracture (36 patients). A single design of THA was implanted. All patients were evaluated before surgery and postoperatively at 1, 3, 6, and 12 months by clinical scores and radiographic studies. The data analysis was made using Student's t -test.

Results  The minimum follow-up was of 4 years, with a mean follow-up of 6.6 years. Two aseptic loosenings of the acetabular component were recorded (one per group), which were not associated with local or systemic complications related to metal ion release. Both were revised by an isolated acetabular cup substitution with metal-on-polyethylene couplings. Nonprogressive radiolucency lines < 2 mm in zone 2 were observed in other six patients around the acetabular component without clinical manifestation (four in the arthritis group and two in the fracture group). Postoperative Harris Hip Score and SF-36 (36-Item Short Form Survey) score improved in both groups.

Conclusion  Despite several MoM implants showing early complications and failures, a specific MoM design may be associated with good clinical results at a mid- to long-term follow-up.

Level of Evidence  This is a therapeutic case series, Level 4 study.

An observational study to determine the sensitizing potential of orthopedic implants

INTRODUCTION

Patients who receive orthopedic implants have been shown to develop sensitivity to its components and there are concerns that this sensitivity might lead to contact dermatitis or implant-related problems like loosening and/or failure. The objective of the study was to determine the sensitizing potential of orthopedic implants.

METHODS

Fifty-four patients undergoing knee, hip, or shoulder replacement surgeries between July 2014 and July 2015 were recruited. Patch tests were performed before the implant surgery with 10 allergens likely to be implicated in metal hypersensitivity. Postimplant patch test was performed 6 months after surgery. A majority of the patch tests were applied on the arms.

RESULTS

Four positive reactions were recorded in the preimplant patch tests - three positive reactions to nickel and one to chromium. Thirty patients made themselves available for the follow-up patch test. The incidence of new contact sensitivity to components of implants was 13.8% (4/29) at 6 months. One patient who had undergone knee replacement developed eczematous lesions around the knee joint after surgery. This patient tested negative to patch test at both the times.

LIMITATIONS

Short follow-up duration and performing patch tests on the arms, a site known to elicit less positive patch test response compared to the back in sensitized individuals, are limitations of the study.

CONCLUSION

There is an increase in the sensitivity to implanted components after 6 months of joint replacement surgery. The incidence of new sensitivity to a component of the implant was 13.8% (4/29). In this context, nickel is a good sensitizer and could sensitize 50% of patients who received a nickel-containing implant.

Blood Metal Ion Release After Primary Total Knee Arthroplasty: A Prospective Study

Objectives

To investigate the course of in vivo blood metal ion levels in patients undergoing primary total knee arthroplasty (TKA) and to investigate potential risk factors associated with metal ion release in these patients.

Methods

Twenty‐five patients with indication for TKA were included in this prospective study. Whole blood metal ion analysis was performed pre‐operatively and at 1 week, 6 weeks, 3 months, 6 months, and 12 months postoperatively. Clinical scores were obtained using the American Knee Society Score (AKSS) and the Oxford Knee Score (OKS) at each follow‐up and patientsʼ activity levels were assessed by measuring the mean annual walking cycles at 12 months follow‐up. Anteroposterior and lateral radiographs of the operated knee were evaluated postoperatively and at 12‐month follow‐up with regard to implant position and radiological signs of implant loosening. Correlation analysis using multivariate linear regression was performed to investigate the influence of different variables (age, gender, functional scores, number of walking cycles, and body mass index [BMI]) on blood cobalt ion concentrations.

Results

Mean metal ion levels of cobalt, chromium, molybdenum, and titanium were 0.28 μg/L (SD, 0.14), 0.43 μg/L (SD, 0.49), 0.62 μg/L (SD, 0.45), and 1.96 μg/L (SD, 0.98), respectively at 12‐month follow‐up. Mean cobalt ion levels significantly increased 1‐year after surgery compared to preoperative measurements. There was no statistically significant increase of mean metal ion levels of chromium, titanium, and molybdenum at 1‐year follow‐up. Overall, metal ion levels were low and no patient demonstrated cobalt ion levels above 1 μg/L. Postoperative radiographs demonstrated well‐aligned TKAs in all patients and no signs of osteolysis or implant loosening were detected at 1‐year follow‐up. Both the AKSS and OKS significantly improved during the course of the study up to the final follow‐up. Multivariate regression analysis did not show a statistically significant correlation between the tested variables and blood cobalt ion concentrations.

Conclusion

A statistically significant increase of mean cobalt ion concentration at 1‐year follow‐up was found in this cohort of patients with well‐functioning TKA, although overall blood metal ion levels were relatively low. Despite low systemic metal ion concentrations seen in this cohort, the local effects of increased metal ion concentrations in the periprosthetic environment on the long‐term outcome of TKA should be further investigated.

The efficacy of an intramedullary nitinol implant in the correction of claw toe or hammertoe deformities

INTRODUCTION

A multitude of procedures has been described in the literature for the treatment of lesser toe deformities and there is currently no general consensus on the optimal method of fixation. The aim of this study is to assess the clinical and radiological outcomes of an intramedullary nitinol implant for the correction of lesser toe deformities, and to determine if the distal interphalangeal (DIP) joint and metatarsophalangeal (MTP) joint are modified during patient follow-up after correction of the PIP joint.

MATERIALS AND METHODS

A prospective analysis of 36 patients with claw toe or hammertoe who were treated with an intramedullary nitinol implant. Clinical manifestations and angulation of the metatarsophalangeal, proximal and distal interphalangeal (MTP, PIP, DIP) joints were evaluated in radiographic studies preoperatively, at first medical revision post-surgery, and after a minimum of 1 year of follow-up. Complications such as non-union rate, implant rupture, and implant infection were also evaluated during follow-up.

RESULTS

All patients were women with an average age of 65.5 (range 47-82) years. The average follow-up time was 2.4 (range 1-5.7) years. Fifty intramedullary nitinol implants were used. The MTP joint extension and PIP joint flexion decreased by 15.9° (95% CI - 19.11 to - 12.63) and 49.4° (95% CI - 55.29 to - 43.52), respectively, at the end of follow-up. Moreover, the DIP joint flexion increased progressively during follow-up (13.7° pre-surgery versus 35.6 in last medical check-up, 95% CI 13.24-30.57). There were four (8%) asymptomatic implant ruptures. The rate of fusion was 98%.

CONCLUSION

The reduction of the PIP joint using an intramedullary nitinol implant is a good option in lesser toe deformities, with few complications and a high rate of arthrodesis. Moreover, the PIP joint reduction affects both the MTP and DIP joints.

Incidence of Metal Hypersensitivity in Orthopedic Surgical Patients Who Self-Report Hypersensitivity History

INTRODUCTION

Metallic implants are integral to the practice of orthopedic surgery. Delayed-onset T-cell-mediated metal hypersensitivity (diagnosed by patch testing) is reported in 10% to 17% of the general population. Inconclusive evidence exists about the role of metal hypersensitivity in persistently painful or aseptic loosening of arthroplasties. Literature suggests that preoperative patch testing may influence surgical practice.

OBJECTIVE

To determine the incidence of metal hypersensitivity in orthopedic surgical patients who self-report hypersensitivity and to characterize which metals are most commonly implicated.

METHODS

A retrospective chart review of patients from a single surgeon's practice was conducted during a 1-year period. All patients were questioned about metal hypersensitivity history; all patients who responded affirmatively were sent for patch testing for specific metals.

RESULTS

Only 41 (4.9%) of 840 patients self-reported any metal hypersensitivity. Of these, 34 (83%) were patch-test positive to 1 or more metals. There were 27 whose test results were positive for nickel, 4 each to cobalt or gold thiosulfate, and 1 each to tin or titanium. Seven patients had positive results to multiple metals, all of whom were also nickel hypersensitive. Six patients had metal orthopedic implants before patch testing, and 4 (67%) tested positively to a metal in their implant.

CONCLUSION

Metal hypersensitivity can be concerning for treating surgeons and patients. Greater awareness of a history to hypersensitivity may prevent patient exposure to implants containing metals that may cause hypersensitivity. Non-metal-containing or nonreactive metal implants are an option for patients in whom metal hypersensitivity is suspected or confirmed.

Increased risk of eczema after joint replacement: A population-based retrospective cohort study

There are very few reports of eczema and other prosthetic-related allergic skin complications following arthroplasty. We aimed to assess the risk of eczema after joint replacement.We performed a retrospective population-based cohort study in 2024 joint replacement patients using the Longitudinal Health Insurance Database. For comparison, 8096 controls were selected, with 4 control subjects for each joint replacement patient matched for age, sex, and index year, to assess eczema risk. We examined 14-year cumulative eczema incidence associated with age, sex, immunity, disease history, and joint replacement location.Eczema rates in the joint replacement patients were 38% higher than in the control group (57.90 vs 41.84 per 1000 person-years, respectively). Compared with the control group, joint replacement patients showed a 1.35-fold increased risk of eczema according to the multivariable Cox model (95% Confidence interval [CI] = 1.23-1.49). Knee replacement patients had higher eczema risk compared with the control group (Hazard ratio [HR] = 1.45, 95% CI = 1.33-1.70). Stratified by study period, the joint replacement cohort had a higher eczema risk after the 3-month follow-up.Our study revealed that joint arthroplasty increased risk of eczema in this 14-year follow-up study, and this was not related to personal atopic history or gender.

Utility of Patch Testing and Lymphocyte Transformation Testing in the Evaluation of Metal Allergy in Patients with Orthopedic Implants

Total joint arthroplasties are increasingly common orthopedic procedures performed throughout the United States. Implant failure after these procedures occurs due to a number of causes such as infection or mechanical problems, with metal hypersensitivity being an area of growing interest. The nature and mechanism of a causative relationship between metal hypersensitivity and implant failure have been unclear as it is not known whether implant failure occurs due to a previous metal allergy or metal allergy results from secondary sensitization via metal exposure in existing failing implants. Overall, there appears to be growing support and evidence for metal-hypersensitive patients having worse outcomes with regard to total hip and knee arthroplasties. However, there are conflicting recommendations (outside of Nuss procedures) for pre-implant testing for metal hypersensitivity as testing has not consistently been shown to change patient outcomes.

Cytokine Profile in Patients with Aseptic Loosening of Total Hip Replacements and Its Relation to Metal Release and Metal Allergy

Metal release from total hip replacements (THRs) is associated with aseptic loosening (AL). It has been proposed that the underlying immunological response is caused by a delayed type IV hypersensitivity-like reaction to metals, i.e., metal allergy. The purpose of this study was to investigate the immunological response in patients with AL in relation to metal release and the prevalence of metal allergy. THR patients undergoing revision surgery due to AL or mechanical implant failures were included in the study along with a control group consisting of primary THR patients. Comprehensive cytokine analyses were performed on serum and periimplant tissue samples along with metal analysis using inductive coupled plasma mass spectrometry (ICP-MS). Patient patch testing was done with a series of metals related to orthopedic implant. A distinct cytokine profile was found in the periimplant tissue of patients with AL. Significantly increased levels of the proinflammatory cytokines IL-1β, IL-2, IL-8, IFN-γ and TNF-α, but also the anti-inflammatory IL-10 were detected. A general increase of metal concentrations in the periimplant tissue was observed in both revision groups, while Cr was significantly increased in patient serum with AL. No difference in the prevalence of metal sensitivity was established by patch testing. Increased levels of IL-1β, IL-8, and TNF-α point to an innate immune response. However, the presence of IL-2 and IFN-γ indicates additional involvement of T cell-mediated response in patients with AL, although this could not be detected by patch testing.

Mechanisms of Adverse Local Tissue Reactions to Hip Implants

Adverse Local Tissue Reactions (ALTRs) are one of the main causes of hip implant failures. Although the metal release from the implants is considered as a main etiology, the mechanisms, and the roles of the released products are topics of ongoing research. The alloys used in the hip implants are considered biocompatible and show negligible corrosion in the body environment under static conditions. However, modularity and its associated mechanically assisted corrosion have been shown to release metal species into the body fluids. ALTRs associated with metal release have been observed in hip implants with metal-on-metal articulation initially, and later with metal-on-polyethylene articulation, the most commonly used design in current hip replacement. The etiological factors in ALTRs have been the topics of many studies. One commonly accepted theory is that the interactions between the metal species and body proteins and cells generate a delayed type IV hypersensitivity reaction leading to ALTRs. However, lymphocyte reactions are not always observed in ALTRS, and the molecular mechanisms have not been clearly demonstrated. A more accepted mechanism is that cell damage generated by metal ions may trigger the secretion of cytokines leading to the inflammatory reactions observed in ALTRs. In this inflammatory environment, some patients would develop hypersensitivity that is associated with poor outcomes. Concerns over ALTRS have brought significant impact to both the clinical selection and development of hip implants. This review is focused on the mechanisms of ALTRs, specifically, the metal release process and the roles of the metal species released in the etiology and pathogenesis of the disease. Hopefully, our presentation and discussion of this biological process from a material perspective could improve our current understanding on the ALTRs and provide useful guidance in developing preventive solutions.

Association between metal hypersensitivity and implant failure in patients who underwent titanium cranioplasty

OBJECTIVE

Digitally designed titanium plates are commonly used for the reconstruction of craniofacial defects, although implant exposure (referred to as failure) is one of the major complications. Metal hypersensitivities have been suggested as possible causes of implant failure of orthopedic, intravascular, gynecological, and dental devices, yet there has been no consensus on the requirement for allergy screening before cranioplasty.

METHODS

In this study, the authors prospectively investigated the prevalence of metal hypersensitivity in patients for whom cranioplasty is planned and assess its relationship with titanium implant failure (exposure).

RESULTS

Based on records from 207 included patients, 39.61% of patients showed hypersensitivity to at least one kind of metal. Approximately one-quarter (25.12%) of patients had multiple metal allergies. Co, Cd, and Zn were the 3 most frequently identified metal hypersensitivities. No allergy to titanium was detected in this study. The overall incidence of cranioplasty implant failure was 5.31% (11 of 207). Patients showing hypersensitivities to more than 3 kinds of metal had higher risks of titanium plate exposure.

CONCLUSIONS

Based on their findings, the authors suggest that routine allergy screening be performed before titanium plate cranioplasty. For patients with hypersensitivities to more than 3 metals, alternative materials, such as polyetheretherketone, should be considered for cranioplasty.

Prevalence of metal hypersensitivity in total knee replacement

Background

Cutaneous and local reactions to metals used in orthopaedic implants have been well documented. The prevalence of metal sensitivity in general population is 10%-15%. Nickel, Cobalt and Chromium are the most common allergen. The association between cutaneous reactions and implants has been less understood. Hence, this study was taken up with the aim to assess the prevalence of metal hypersensitivity in Total Knee Replacement (TKR) patients and find the most prevalent allergen.

Materials & methods

Longitudinal study conducted during January-December 2017. We enrolled 233 subjects who were at least three months postoperative. Radiological assessment was done. CREDISOL® kit was used for patch test. Results were recorded using ICDRG grading at 48 hours and five days.

Results

Mean age was 59.59 years; 12.01% were symptomatic. Pain followed by loss of function were the most common symptoms. However, loss of function and patient dissatisfaction towards procedure were significantly associated with metal hypersensitivity (χ² value > 3.84; p value < 0.05). In 66% subjects, pre-operative diagnosis was severe osteoarthritis, followed by rheumatoid arthritis (23%). None of the subjects had evidence of loosening on X-ray. Prevalence of Metal Hypersensitivity was found to be 15.87% (patch test positive). Chromium (11.58%) was found to be most common allergen followed by Nickel (8.58%) and then Cobalt (6.43%).

Conclusions

Significant prevalence of metal hypersensitivity was found. Therefore, we recommend pre-operative patch test for detecting allergic reactions to implants. Alternatives like Titanium or Zirconium can be used to avoid complications.

Exploring the Incidence, Implications, and Relevance of Metal Allergy to Orthopaedic Surgeons

Introduction:

Allergic reactions to metal implants are increasingly recognized, but its relevance to the orthopaedic surgeon remains unclear. We evaluate the prevalence of metal allergies in a subset of the population and review the significance through a survey of the current literature.

Methods:

Preoperative and postoperative patients referred for metal allergy testing were divided into two groups; those with a history of dermatitis and those without. Patients with a history of dermatitis were offered skin patch testing that included the North American Contact Dermatitis core allergen panels in addition to our metal screening series. Patients without dermatitis were tested to the more limited patch testing metal screening series. Some patients with dermatitis opted for the more limited screening, whereas some patients without dermatitis underwent more extensive testing at their request or at the request of the referring clinician. Patch tests were evaluated at 2 and 4 days after placement.

Results:

Hundred patients were referred for metal allergy testing, 46 of whom were for reasons related to planned orthopaedic surgery. Of those tested, 60 patients had a history of dermatitis and 40 did not. Some patients were nonreactive to all tested allergens, whereas others demonstrated one or more positive skin patch test reactions. The number of positive reactions to each metal in patients with a history of dermatitis was the following: nickel 19, amalgam 10, palladium 10, copper 8, cobalt 5, mercury 5, tin 2, gold 1, titanium 1, and vanadium 1. The number of positive reactions to metals in patients without a history of dermatitis was the following: nickel 4, amalgam 5, palladium 4, mercury 4, cobalt 4, tin 2, copper 2, gold 1, vanadium 1, and molybdenum 1.

Discussion:

Metal allergy was common in the individuals referred for testing, with reactions to nickel and amalgam being the most commonly encountered. Some individuals experience more notable allergic reactions to implanted devices than others. Localized and generalized skin reactions have been reported, along with implant failure and loosening. Surgeons should be aware of the incidence of metal allergies and the potential consequences.

Allergy in total knee replacement surgery: Is it a real problem?

Total knee arthroplasty is a common procedure, with extremely good clinical results. Despite this success, it produces 20% unsatisfactory results. Among the causes of these failures is metal hypersensitivity. Metal sensitization is higher in patients with a knee arthroplasty than in the general population and is even higher in patients undergoing revision surgery. However, a clear correlation between metal sensitization and symptomatic knee after surgery has not been ascertained. Surely, patients with a clear history of metal allergy must be carefully examined through dermatological and laboratory testing before surgery. There is no globally accepted diagnostic algorithm or laboratory test to diagnose metal hypersensitivity or metal reactions. The patch test is the most common test to determine metal hypersensitivity, though presenting some limitations. Several laboratory assays have been developed, with a higher sensitivity compared to patch testing, yet their clinical availability is not widespread, due to high costs and technical complexity. Symptoms of a reaction to metal implants present across a wide spectrum, ranging from pain and cutaneous dermatitis to aseptic loosening of the arthroplasty. However, although cutaneous and systemic hypersensitivity reactions to metals have arisen, thereby increasing concern after joint arthroplasties, allergies against implant materials remain quite rare and not a well-known problem. The aim of the following paper is to provide an overview on diagnosis and management of metal hypersensitivity in patients who undergo a total knee arthroplasty in order clarify its real importance.

Lymphocyte Transformation Testing (LTT) in Cases of Pain Following Total Knee Arthroplasty: Little Relationship to Histopathologic Findings and Revision Outcomes

BACKGROUND

The utilization of lymphocyte transformation testing (LTT) has increased for diagnosing metal sensitivity associated with total knee arthroplasty (TKA), but its validity for the diagnosis of TKA failure due to an immune reaction has not been established. In this study, we sought to characterize the relationship of a positive LTT result to histopathologic findings and clinical and functional outcomes.

METHODS

This was a retrospective study of 27 well-fixed, aseptic, primary TKA cases in which the patient had persistent pain and/or stiffness and underwent revision due to a suspected metal allergy to nickel, as determined on the basis of positive LTT. Revision procedures were performed by a single experienced arthroplasty surgeon. Periprosthetic tissue samples obtained at the time of revision surgery were scored using the aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) scoring system.

RESULTS

Eight patients were categorized as mildly reactive; 8 patients, moderately reactive; and 11 patients, highly reactive to nickel by LTT. The predominant findings on routine histopathologic analysis were fibrosis and varying degrees of lymphocytic infiltration in 17 (63%) of the 27 cases. The average ALVAL score of the cohort was 3.1 ± 1.9, of a maximum score of 10. Average Knee Society Score (KSS) values improved post-revision, as did range of motion (all p < 0.01). Neither LTT stimulation index as a continuous variable nor as a categorical variable (mildly reactive, moderately reactive, highly reactive) was correlated with ALVAL score, pre-revision function (as assessed by KSS-clinical, KSS-functional, and range of motion), or change in function at the most recent follow-up (0.015 < r < 0.30, 0.13 < p < 0.95). In addition, the ALVAL score did not correlate significantly with either pre-revision or post-revision KSS or range of motion (0.061 < r < 0.365, 0.09 < p < 0.88).

CONCLUSIONS

On the basis of this analysis, including histopathologic assessment, LTT results alone were insufficient for the diagnosis of TKA failure due to an immune reaction. A positive LTT may not indicate that an immune reaction is the cause of pain and stiffness post-TKA. The role of LTT in assessing TKA failure from an immune reaction needs further investigation. Diagnostic criteria for such TKA failure need to be established.

LEVEL OF EVIDENCE

Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Modifiable and Nonmodifiable Predictive Factors Associated with the Outcomes of Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a valuable treatment option for advanced osteoarthritis in patients unresponsive to conservative treatments. Despite overall satisfactory results, the rate of unsatisfied patients after TKA remains high, ranging from 5 to 40%. Different modifiable and nonmodifiable prognostic factors associated with TKA outcomes have been described. The correction, whenever possible, of modifiable factors is fundamental in preoperative patients' optimization protocols. Nonmodifiable factors can help in predicting the outcomes and creating the right expectations in the patients undergoing TKA. The goal of this review is to summarize the modifiable and nonmodifiable prognostic factors associated with TKA outcomes.