Pseudotumors and High-Grade Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesions Around Total Knee Replacements Identified at Aseptic Revision Surgery: Findings of a Large-Scale Histologic Review

Metallosis-Induced Warm Antibody Auto-Immune Hemolytic Anemia After Bilateral, Large-Diameter Metal-on-Metal Total Hip Arthroplasty With Complete Remission After Revision

The use of metal-on-metal bearing couples in total hip arthroplasty can lead to an increased release of metal ions, particularly cobalt and chromium over time. This can lead to local and systemic metallosis, which has cytotoxic, genotoxic, and immunotoxic effects and can cause a host of secondary disorders. We describe the case of a 37-year-old female patient that was diagnosed with warm-antibody autoimmune hemolytic anemia (WAIHA) one and a half years after bilateral large-diameter head metal-on-metal total hip arthroplasty. For 11 years, it was refractory to all therapy, including splenectomy and rituximab, requiring long-term oral prednisone for disease control. Ultimately, systemic metallosis and periprosthetic joint infection were diagnosed, requiring explantation of the prostheses. By the sixth week postoperatively, she experienced complete spontaneous remission of her WAIHA. In conclusion, WAIHA can be associated with systemic metallosis in patients with metal-on-metal prosthetic joint replacements. Both hematologists and orthopedic surgeons should be aware of this.

Comparative Study of Zirconium Nitride Multilayer Coatings: Crystallinity, In Vitro Oxidation Behaviour and Tribological Properties Deposited via Sputtering and Arc Deposition

This study aims to evaluate and compare the properties of a biomedical clinically established zirconium nitride (ZrN) multilayer coating prepared using two different techniques: pulsed magnetron sputtering and cathodic arc deposition. The investigation focuses on the crystalline structure, grain size, in-vitro oxidation behaviour and tribological performance of these two coating techniques. Experimental findings demonstrate that the sputter deposition process resulted in a distinct crystalline structure and smaller grain size compared to the arc deposition process. Furthermore, in vitro oxidation caused oxygen to penetrate the surface of the sputtered ZrN top layer to a depth of 700 nm compared to 280 nm in the case of the arc-deposited coating. Finally, tribological testing revealed the improved wear rate of the ZrN multilayer coating applied by sputter deposition.

Friend or foe? Inflammation and the foreign body response to orthopedic biomaterials

The use of biomaterials and implants for joint replacement, fracture fixation, spinal stabilization and other orthopedic indications has revolutionized patient care by reliably decreasing pain and improving function. These surgical procedures always invoke an acute inflammatory reaction initially, that in most cases, readily subsides. Occasionally, chronic inflammation around the implant develops and persists; this results in unremitting pain and compromises function. The etiology of chronic inflammation may be specific, such as with infection, or be unknown. The histological hallmarks of chronic inflammation include activated macrophages, fibroblasts, T cell subsets, and other cells of the innate immune system. The presence of cells of the adaptive immune system usually indicates allergic reactions to metallic haptens. A foreign body reaction is composed of activated macrophages, giant cells, fibroblasts, and other cells often distributed in a characteristic histological arrangement; this reaction is usually due to particulate debris and other byproducts from the biomaterials used in the implant. Both chronic inflammation and the foreign body response have adverse biological effects on the integration of the implant with the surrounding tissues. Strategies to mitigate chronic inflammation and the foreign body response will enhance the initial incorporation and longevity of the implant, and thereby, improve long-term pain relief and overall function for the patient. The seminal research performed in the laboratory of Dr. James Anderson and co-workers has provided an inspirational and driving force for our laboratory's work on the interactions and crosstalk among cells of the mesenchymal, immune, and vascular lineages, and orthopedic biomaterials. Dr. Anderson's delineation of the fundamental biologic processes and mechanisms underlying acute and chronic inflammation, the foreign body response, resolution, and eventual functional integration of implants in different organ systems has provided researchers with a strategic approach to the use of biomaterials to improve health in numerous clinical scenarios.

Understanding immune-mediated titanium allergy to in situ orthopaedic implants: a narrative review of the current literature

INTRODUCTION

Clinical recognition of potential immune-mediated allergic responses to implanted metal devices is increasing. For orthopaedic implants, while 'pure' compounds are used in specific circumstances, the majority of components are alloys - a combination of two or more distinct metals. Titanium is found commonly in many orthopaedic devices and is often championed as a 'hypoallergenic' option or inclusion. In the absence of a relevant previously published summary on the topic, this paper explores the current state-of-understanding of titanium allergy and proposes a patient management algorithm whereby such immune reactions are clinically-suggested.

METHODS

A structured, systematic literature review was performed following PRISMA search principles to provide a contemporary summary-of-understanding in this area and to highlight clinical and knowledge deficiencies.

RESULTS

Thirty-five topic-related articles were identified, the majority reflecting small case series' or proof-of-concept studies. The general standard of scientific evidence available was poor. Justification for arthroplasty utilization of titanium as a 'hypoallergenic' option is largely extrapolated from non-orthopaedic domains.

CONCLUSIONS

Both ionic and conjugated titanium particles released from implant surfaces have the potential to trigger innate immune responses and true allergy. There exists no simple, high-sensitivity, screening test for titanium allergy. Conventional skin-patch testing is unreliable due to poor dermal penetration. Given established lymphocyte and macrophage activation pathways for allergy responses, in vitro methods using both cell-types show diagnostic promise. Surgical biopsy analysis from host-implant interfaces remains the contemporary 'gold-standard', however this represents an invasive, costly and highly-specialized approach not readily available in most settings. Further research to establish reliable/accessible diagnostic methods are indicated.

Titanium-Titanium Junctions in the Knee Corrode, Generating Damage Similar to the Hip

BACKGROUND

Previous studies identified corrosion between the modular tibial components of total knee arthroplasty devices. However, gaps persist. Compared to the hip, damage modes that occur within taper junctions in the knee remain poorly understood. In this study, we investigated corrosion on total knee arthroplasty components with titanium-titanium junctions. We asked the following question: under typical in vivo cyclic loading conditions, will the same alloy damage modes from total knee arthroplasty devices resemble those documented in the hip?

METHODS

A total of 50 paired titanium alloy tibial baseplates and stems were collected and semiquantitatively analyzed using Goldberg corrosion scoring. To characterize damage, a subsection of moderately and severely corroded components was sectioned and imaged using scanning electron and digital optical microscopy.

RESULTS

Of the 100 device components, 95% showed visual evidence of corrosion. The initial contact area between the stem and bore generally occurred 3 mm from the stem taper base. Scanning electron microscopy revealed 4 damage modes, including oxide film formation, crevice corrosion, selective dissolution, and pitting.

CONCLUSIONS

Each of the damage modes identified in modular titanium-titanium tibial junctions was previously reported by total hip arthroplasty retrieval studies. Cumulatively, our results suggest that mechanically assisted crevice corrosion promoted this damage in vivo.

Femtosecond Laser Irradiation to Zirconia Prior to Calcium Phosphate Coating Enhances Osteointegration of Zirconia in Rabbits

Calcium phosphate (CaP) coating of zirconia and zirconia-based implants is challenging, due to their chemical instability and susceptibility to thermal and mechanical impacts. A 3 mol% yttrium-stabilized tetragonal zirconia polycrystal was subjected to femtosecond laser (FsL) irradiation to form micro- and submicron surface architectures, prior to CaP coating using pulsed laser deposition (PLD) and low-temperature solution processing. Untreated zirconia, CaP-coated zirconia, and FsL-irradiated and CaP-coated zirconia were implanted in proximal tibial metaphyses of male Japanese white rabbits for four weeks. Radiographical analysis, push-out test, alizarin red staining, and histomorphometric analysis demonstrated a much improved bone-bonding ability of FsL-irradiated and CaP-coated zirconia over CaP-coated zirconia without FsL irradiation and untreated zirconia. The failure strength of the FsL-irradiated and CaP-coated zirconia in the push-out test was 6.2-13.1-times higher than that of the CaP-coated zirconia without FsL irradiation and untreated zirconia. Moreover, the adhesion strength between the bone and FsL-irradiated and CaP-coated zirconia was as high as that inducing host bone fracture in the push-out tests. The increased bone-bonding ability was attributed to the micro-/submicron surface architectures that enhanced osteoblastic differentiation and mechanical interlocking, leading to improved osteointegration. FsL irradiation followed by CaP coating could be useful for improving the osteointegration of cement-less zirconia-based joints and zirconia dental implants.

Concentrations of Cobalt, Chromium and Titanium and Immunological Changes after Primary Total Knee Arthroplasty-A Cohort Study with an 18-Year Follow-Up

Background: Total knee arthroplasty (TKA) generates elevated metal ion concentrations, but long-term changes in the concentrations of cobalt (Co), chromium (Cr) and titanium (Ti) after primary TKA and potential subsequent immune system activation-not limited to the joint but systemically-are not known. Patients and Methods: We conducted a cohort study on 26 patients with TKA (19 women; 16 with metal-backed and 10 with all-polyethylene tibial components) 18.3 years (min. 16.7, max. 20.5) after index TKA. A total of 69% of patients additionally underwent subsequent arthroplasty of the contralateral knee or either hip after the index surgery. Blood samples were analysed by inductively coupled plasma-mass spectrometry, and leukocytes were characterised by flow cytometry. Patients were clinically assessed using the Knee Society score and by plain radiography of the knee. Results: The median metal ion concentrations were 0.7 (0.1-13.0) µg/L for Co, 0.9 (0.4-5.0) µg/L for Cr, and 1.0 (0.2-13.0) µg/L for Ti. There was no relevant difference in systemic metal ion concentrations between patients exposed to single and multiple arthroplasties. The absolute count and proportion of CD3+CD4+CD8+ T cells was inversely correlated with both Co (rho -0.55, p = 0.003) and Cr concentrations (rho -0.59, p = 0.001). Conclusions: Between the first and second decades after primary TKA, in most patients, the concentrations of Co, Cr and Ti in blood samples were below the thresholds that are considered alarming. The negative correlation of Co and Cr concentrations with a subset of lymphocytes that commonly increases during immune activation is reassuring. This represents a worst-case scenario, underscoring that the investigated metal ions remain within reasonable ranges, even after additional hardware exposure.

Understanding immune-mediated cobalt/chromium allergy to orthopaedic implants: a meta-synthetic review

BACKGROUND

The frequency of primary joint replacement surgery continues to increase worldwide. While largely considered biologically inert entities, an increasing body of evidence continues to validate a not insignificant incidence of allergic reactions to such implants. Little previous work has explored genuinely immune-mediated reactivity in this context. In the absence of a contemporary published summary on the topic, this paper explored the current state of understanding of cobalt/chromium allergy and proposes a patient management algorithm whereby such immune reactions are clinically suggested.

METHODS

A structured, systematic literature review was performed by following PRISMA search principles to provide an updated review of this area.

RESULTS

Thirty-six topic-related articles were identified, the majority reflecting lower tiers of scientific evidence with a lack of homogeneous quantitative data to facilitate valid cohort comparisons. Largely, the available literature represented small case series' or expert opinions.

CONCLUSIONS

Despite increasing clinical awareness and acknowledgement of true allergy to joint replacement components, this review highlighted that the evidence base underpinning the diagnosis and management of such patients is limited. Both patient-reported metal allergy or skin patch testing are grossly unreliable methods and show almost no correlation with true immune reactivity. Recent studies suggested a potential role for patient-specific in vitro cellular activation testing and/or targeted genetic testing when cobalt/chromium allergy is clinically suspected. However, while likely representing the contemporary "best available" approaches both can be costly undertakings, are not yet universally available, and still require broader validation in non-research settings before wider uptake can be championed.

The Diagnostic Utility of Serum Metal Ion Markers for High-Grade Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesions (ALVALs) in Revision Hip and Knee Arthroplasty: An International Multicenter Study

BACKGROUND

Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) are typically described in the context of metal-on-metal (MoM) hip bearings. This study explores the diagnostic utility of preoperative serum cobalt and chromium ion levels in determining the histological grade of ALVAL in revision hip and knee arthroplasty.

METHODS

This was a multicenter retrospective review of 26 hips and 13 knees assessing the correlation between preoperative ion levels (mg/L (ppb)) and the histological grade of ALVAL from intraoperative specimens. The diagnostic ability of preoperative serum cobalt and chromium levels to determine high-grade ALVAL was assessed using a receiver operating characteristic (ROC) curve.

RESULTS

In the knee cohort, there was a higher serum cobalt level in high-grade ALVAL cases (10.2 mg/L (ppb) versus 3.1 mg/L (ppb)) (P = .0002). The Area Under the Curve (AUC) was 1.00 (95% confidence interval (CI) 1.00 to 1.00). There was a higher serum chromium level in high-grade ALVAL cases (12.25 mg/L (ppb) versus 7.77 mg/L (ppb)) (P = .0002). The AUC was 0.806 (95% CI 0.555 to 1.00). In the hip cohort, there was a higher serum cobalt level in high-grade ALVAL cases (333.5 mg/L (ppb) versus 119.9 mg/L (ppb)) (P = .0831). The AUC was 0.619 (95% CI 0.388 to 0.849). There was a higher serum chromium level in high-grade ALVAL cases (186.4 mg/L (ppb) versus 79.3 mg/L (ppb)) (P = .183). The AUC was 0.595 (95% CI 0.365 to 0.824).

CONCLUSIONS

Histologically, high-grade ALVAL has significantly higher preoperative serum cobalt and chromium ion levels in revision TKA. Preoperative serum ion levels have excellent diagnostic utility in revision TKA. Cobalt levels in revision THA have a fair diagnostic ability and chromium levels had a poor diagnostic ability.

Identification of protective and 'at risk' HLA genotypes for the development of pseudotumours around metal-on-metal hip resurfacings

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. 'Controls' were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size. Using a previously-reported ALVAL classification, the majority of pseudotumour-positive caseswere found to have intermediate-grade group 2 (n = 10; 63%) or group 3 (n = 4; 25%) histological findings. Two further patients (13%) had high-grade group 4 lesions. HLA-DQB1*05:03:01 (p = 0.0676) and HLA-DRB1*14:54:01 (p = 0.0676) alleles were significantly associated with a higher risk of pseudotumour formation, while HLA-DQA1*03:01:01 (p = 0.0240), HLA-DRB1*04:04:01 (p = 0.0453), HLA-C*01:02:01 (p = 0.0453), and HLA-B*27:05:02 (p = 0.0855) were noted to confer risk reduction. These findings confirm the association between specific HLA genotypes and the risk of pseudotumour development around MoM hip resurfacings. Specifically, the two 'at risk' alleles (DQB1*05:03:01 and DRB1*14:54:01) may hold clinical value in preoperative screening and prospective surgical decision-making.

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.

The influence of HLA genotype on the development of metal hypersensitivity following joint replacement

Background

Over five million joint replacements are performed across the world each year. Cobalt chrome (CoCr) components are used in most of these procedures. Some patients develop delayed-type hypersensitivity (DTH) responses to CoCr implants, resulting in tissue damage and revision surgery. DTH is unpredictable and genetic links have yet to be definitively established.

Methods

At a single site, we carried out an initial investigation to identify HLA alleles associated with development of DTH following metal-on-metal hip arthroplasty. We then recruited patients from other centres to train and validate an algorithm incorporating patient age, gender, HLA genotype, and blood metal concentrations to predict the development of DTH. Accuracy of the modelling was assessed using performance metrics including time-dependent receiver operator curves.

Results

Using next-generation sequencing, here we determine the HLA genotypes of 606 patients. 176 of these patients had experienced failure of their prostheses; the remaining 430 remain asymptomatic at a mean follow up of twelve years. We demonstrate that the development of DTH is associated with patient age, gender, the magnitude of metal exposure, and the presence of certain HLA class II alleles. We show that the predictive algorithm developed from this investigation performs to an accuracy suitable for clinical use, with weighted mean survival probability errors of 1.8% and 3.1% for pre-operative and post-operative models respectively.

Conclusions

The development of DTH following joint replacement appears to be determined by the interaction between implant wear and a patient's genotype. The algorithm described in this paper may improve implant selection and help direct patient surveillance following surgery. Further consideration should be given towards understanding patient-specific responses to different biomaterials.

Patient-reported outcome measures following revision knee replacement: a review of PROM instrument utilisation and measurement properties using the COSMIN checklist

OBJECTIVES

To identify: (1) patient-reported outcome measures (PROMs) used to evaluate symptoms, health status or quality of life following discretionary revision (or re-revision) knee joint replacement, and (2) validated joint-specific PROMs, their measurement properties and quality of evidence.

DESIGN

(1) Scoping review; (2) systematic review following the COnsensus-based Standards for selection of health status Measurement INstruments (COSMIN) checklist.

DATA SOURCES

MEDLINE, Embase, AMED and PsycINFO were searched from inception to 1 July 2020 using the Oxford PROM filter unlimited by publication date or language.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies reporting on the development, validation or outcome of a joint-specific PROM for revision knee joint replacement were included.

RESULTS

51 studies reported PROM outcomes using eight joint-specific PROMs. 27 out of 51 studies (52.9%) were published within the last 5 years. PROM development was rated 'inadequate' for each of the eight PROMs studied. Validation studies were available for only three joint-specific PROMs: Knee Injury and Osteoarthritis Outcome Score (KOOS), Lower Extremity Activity Scale (LEAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). 25 out of 27 (92.6%) measurement properties were rated insufficient, indeterminate or not assessed. The quality of supporting evidence was mostly low or very low. Each of the validated PROMs was rated 'B' (potential for recommendation but require further evaluation).

CONCLUSION

Joint-specific PROMs are increasingly used to report outcomes following revision knee joint replacement, but these instruments have insufficient evidence for their validity. Future research should be directed toward understanding the measurement properties of these instruments in order to inform clinical trials and observational studies evaluating the outcomes from joint-specific PROMs.

Pathological analysis of periprosthetic soft tissue and modes of failure in revision total joint arthroplasty patients

Objectives

Implant failure leading to revision total joint arthroplasty can occur through a variety of different mechanisms which are typically associated with a soft tissue response adjacent to the implant that provide insight into the underlying etiology of implant failure. The objective of this study was to elucidate mechanisms of implant failure as they relate to histological classification and findings of adjacent periprosthetic tissue.

Methods

Histological analysis of soft tissue adjacent to the implant was performed in 99 patients with an average age of 64 years old and grouped into four categories based on the study conducted by Morawietz et al.:Type I (N = 47)Wear particle induced typeType II (N = 7)Infectious typeType III (N = 19)Combined type I and IIType IV (N = 26)Indeterminant typeModes of failure were categorized into five groupings based on the study conducted by Callies et al.: Instability (N = 35), Aseptic Loosening (N = 24), Hardware and/or Mechanical Failure (N = 15), Septic (N = 13), and Other failures (N = 12). We calculated odds ratios and conducted regression analysis to assess the relationship between modes of failure and histological findings as well as modes of failure and comorbidities.

Results

Hardware/mechanical failure was independently correlated with histological findings of anucleate protein debris, histiocytes, Staphylococcus epidermidis, and synovitis. Furthermore, hardware/mechanical failure was independently correlated with osteosarcoma as a co-morbidity. Septic failure was associated with histological findings of Enterococcus, granulation tissue, and tissue necrosis as well as comorbidities of Crohn's disease, deep venous thrombosis, lung disease, and rheumatoid arthritis. Infection was 5.8 times more likely to be associated with Type II histology. Aseptic loosening was associated with histologic findings of synovitis.

Conclusion

Our findings support the existing literature on periprosthetic tissue analysis in revision total joint arthroplasty which may improve surgeon understanding of the patholophysiological mechanisms that contribute to implant failure and revision surgery.

Adaptive Immune Response Associated with a Zirconium-Containing, Cemented, Total Knee Arthroplasty: A Case Report

CASE

A 69-year-old woman underwent revision total knee arthroplasty for patellar component aseptic loosening. The periprosthetic tissue demonstrated histologic features of an adaptive immune response (aseptic lymphocyte-dominant vasculitis-associated lesion [ALVAL]). No particles of corrosion debris were identified. The inflammation seemed to be associated with zirconium oxide (ZrO2) particles added as a bone cement radio-opacifier.

CONCLUSION

The factors responsible for the adaptive immune response cannot be determined with certainty; however, this is the first reported case of ALVAL associated with ZrO2-containing bone cement. Previous reports describing ALVAL around failed total knee prostheses have not included observations about the type of contrast material added to cement.

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.

Aseptic lymphocytic vasculitis-associated lesion in a well-fixed total knee arthroplasty: a case report

Adverse reactions to metal debris in relation to metal-on-metal hip arthroplasty has been heavily discussed in the literature. In contrast, few cases have been reported in the context of total knee arthroplasty. A 77-year-old woman presented with a painful total knee arthroplasty. At the time of revision surgery, intra-articular cream-coloured fluid and material was found in association with a well-fixed prosthesis. Synovial and capsular samples were obtained for histological assessment and a diagnosis of aseptic lymphocytic vasculitis associated lesion was confirmed. The patient went on to have an uncomplicated recovery following a two-stage revision to a constrained knee prosthesis.

Eradicating Fungal Periprosthetic TKA "Super-infection": Review of the Contemporary Literature and Consideration of Antibiotic-Impregnated Dissolving Calcium Sulfate Beads as a Novel PJI Treatment Adjunct

Fungal periprosthetic joint infections are an uncommon but potentially devastating complication of arthroplasty surgery. The concurrent presence of a coexistent bacterial pathogen—a so called “super-infection”—adds further complexity. With delays to definitive diagnosis and a large number of procedures before cure, the associated physical and psychological morbidity is considerable. Beyond this, the economic and resource burden can be substantial. This case report presents the successful rapid treatment of an atypical bacterial and fungal periprosthetic super-infection with two-stage revision surgery augmented with a commercially available dissolving calcium sulfate bead system permitting targeted local antifungal elution. While not the panacea for treatment, these beads provide another potentially useful tool in the atypical pathogen eradication armamentarium. Much research is still indicated to define the optimal care pathway for fungal periprosthetic super-infections.

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.

Metallosis after knee replacement: a review

INTRODUCTION

Although metallosis is a well-known complication after total hip arthroplasty, little is known about this phenomenon after total (TKA) or unicompartmental knee arthroplasty (UKA). The aim of the present work was to review the current knowledge about the reasons and the diagnostic as well as therapeutic management of metallosis after knee arthroplasty.

MATERIALS AND METHODS

A literature search was performed through PubMed until April 2019. Search terms were "metallosis" in combination with "knee", "knee prosthesis", "knee arthroplasty" and "knee replacement", respectively. All publications were analyzed regarding publication year, level of evidence, number of knees/patients treated, type of prosthesis, metallosis cause, time period between primary implantation and metallosis emergence, laboratory examination, treatment, complications and follow up.

RESULTS

A total of 38 studies reporting on a total of 97 knees were identified. 29 studies reported on metallosis after TKA, 8 after UKA, and one study after both procedures. The time period between the primary implantation and metallosis emergence ranged between 6 weeks and 26 years. The most common reason was the failure of a metal-backed patellar component in 40%, followed by implant/structural- and PE failure (wear/dislocation) in 27% and 18% of the cases, respectively. Complete blood cell count, serum chemistry, erythrocyte sedimentation rate or C-reactive protein serum values were not indicative to diagnose metallosis. The diagnosis was confirmed by histopathological analyses and macroscopic evaluation during surgery. Depending on the particular cause various surgical procedures have been performed. Complete prosthesis exchange was the most common one showing no complications in 89.4% of the cases.

CONCLUSIONS

Metallosis after knee arthroplasty is a rare and perhaps underestimated or under published complication. A systematic diagnostic approach is necessary for the timely and correct diagnosis. A thorough debridement as well as a (sub)total synovectomy should be always performed. In cases with a damaged component, a partial/complete prosthesis exchange leads to the best results. Should a malalignment be the cause of the metallosis, then it should be corrected within the revision surgery.