The relationship between pseudotumours and infected complications in patients who have undergone metal-on-metal total hip arthroplasty.

Aims: This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection. Methods: A total of 1,171 total hip arthroplasty (THA) patients with MoM articulations from August 2000 to March 2014 were retrospectively identified. Of those, 328 patients underwent metal artefact reduction sequence MRI and had minimum two years' clinical follow-up, and met our inclusion criteria. Data collected included demographic details, surgical indication, laterality, implants used, history of pseudotumour, and their corresponding preoperative ESR (mm/hr) and CRP (mg/dl) levels. Multivariate logistic regression modelling was used to evaluate PJI and history of pseudotumour, and receiver operating characteristic curves were created to assess the diagnostic capabilities of ESR and CRP to determine the presence of infection in patients undergoing revision surgery. Results: The rate of PJI for all identified MoM THAs was 3.5% (41/1,171), with a mean follow-up of 10.9 years (2.0 to 20.4). Of the patients included in the final cohort, 8.2% (27/328) had PJI, with a mean follow-up of 12.2 years (2.3 to 20.4). Among this cohort, 31.1% (102/328) had a history of pseudotumour. The rate of PJI in these patients was 14.7% (15/102), which was greater than those without pseudotumour, 5.3% (12/226) (p = 0.008). Additionally, logistic regression analysis showed an association between history of pseudotumour and PJI (odds ratio 4.36 (95% confidence interval 1.77 to 11.3); p = 0.002). Optimal diagnostic cutoffs for PJI in patients with history of pseudotumour versus those without were 33.1 mm/hr and 24.5 mm/hr for ESR and 7.37 mg/dl and 1.88 mg/dl for CRP, respectively. Conclusion: Patients with history of pseudotumour secondary to MoM THA had a higher likelihood of infection than those without. While suspicion of infection should be high for these patients, ESR and CRP cutoffs published by the European Bone and Joint Infection Society may not be appropriate for patients with a history of pseudotumour, as ESR and CRP levels suggestive of PJI are likely to be higher than for those without a pseudotumour. Additional investigation, such as aspiration, is highly recommended for these patients unless clinical suspicion and laboratory markers are low.

Case report: inflammatory pseudotumor in the lung parenchyma caused by a medical suture originating from a cardiac surgery 35 years ago.

BACKGROUND: The incidence of the iatrogenic foreign body retained after surgery is extremely low. Iatrogenic foreign body retained is surrounded by normal tissue, which responds to foreign matter to form inflammatory pseudotumors. Surgical sponge or swap is the most common type of foreign body. There were no reports of medical sutures remaining as foreign bodies in the lung parenchyma to form inflammatory pseudotumors. CASE PRESENTATION: A CT scan of a 50-year-old female showed an irregular soft tissue mass in the left upper lobe with rough edge and spiculation. After 20 months, the size increased from 2.8 × 1.9 cm to 3.2 × 2.2 cm. The patient underwent a ventricular septal repair surgery for congenital Fallot tetralogy 35 years ago and a left breast surgery for breast cancer. She had a family history of lung cancer. Evaluation of this mass highly suggested a lung malignant lesion. The patient underwent video-assisted thoracoscopic surgery (VATS) lobectomy and her pathology revealed an intrapulmonary inflammatory pseudotumor caused by a medical prolene suture. Based on her medical history and other reports of iatrogenic foreign bodies, we believe that this suture retained from the heart surgery 35 years ago entered the pulmonary artery, moved to the distal branch, and eventually formed an inflammatory pseudotumor in the lung parenchyma. Here we reported and analyze this rare case. CONCLUSION: We reported a rare case of inflammatory pseudotumor in the lung parenchyma caused by a medical suture, and determined it was a prolene suture retained in the body during a cardiac surgery 35 years ago. Diagnosis of this rare disease required sufficient imaging experience. Besides, appropriate surgical exploration can help with the diagnosis and treatment.

Pseudotumor Caused by a Retained Intra-articular Bullet: A Case Report.

CASE: A 54-year-old man presented with systemic lead poisoning due to a gunshot wound to the hip suffered 35 years prior to presentation. He urgently underwent removal of the bullet with total hip arthroplasty and was found to have a pseudotumor. This case highlights the team-based approach to manage systemic lead poisoning caused by an intra-articular bullet. CONCLUSION: We report on the first documented case of systemic lead toxicity and a pseudotumor caused by an intra-articular bullet. An expeditious, team-based approach is necessary for appropriate treatment. Our treatment algorithm can guide future teams on the management of this reversible disorder.

Pseudotumours, cobalt and clinical outcome in small head metal-on-metal versus conventional metal-on-polyethylene total hip arthroplasty.

BACKGROUND: Metal-on-metal total hip arthroplasty (MoM THA) is associated with the formation of pseudotumours. Studies mainly concern pseudotumour formation in large head MoM THA. We performed a long-term follow-up study, comparing pseudotumour incidence in small head metal-on-metal (SHMoM) THA with conventional metal-on-polyethylene (MoP) THA. Predisposing factors to pseudotumour formation were assessed. METHODS: From a previous randomised controlled trial comparing SHMoM (28 mm) cemented THA with conventional MoP cemented THA, patients were screened using a standardised CT protocol for the presence of pseudotumours. Serum cobalt levels and functional outcome were assessed. RESULTS: 56 patients (33 MoP and 23 MoM) were recruited after mean follow-up of 13.4 years (SD 0.5). The incidence of pseudotumours was 1 (5%) in the SHMoM THA cohort and 3 (9%) in the MoP THA cohort. Prosthesis survival was 96% for both SHMoM and MoP THAs. Serum cobalt levels did not exceed acceptable clinical values (<5 µg/L) whereas no differences in cobalt levels were detected at follow-up between both groups. Oxford and Harris Hip Scores were good and did not differ between SHMoM and MoP THA. CONCLUSIONS: This long-term follow-up study shows a low incidence of pseudotumour formation and good functional outcome in cemented head-taper matched SHMoM and MoP THA.

Intracranial Inflammatory Pseudotumor Associated with Idiopathic Hypertrophic Pachymeningitis Mimicking Malignant Tumor or High-Grade Meningioma.

BACKGROUND: Idiopathic hypertrophic pachymeningitis (IHP) is a rare clinical disease characterized by inflammatory fibrosis, which causes diffuse thickening of the dura mater. The inflammatory fibrosis will be locally invasive in nature but will be characterized by a benign histological appearance, known as an inflammatory pseudotumor. We present the case of a patient with an infiltrative lesion involving the right frontal convexity diagnosed as IHP, which had been suspected to be a malignant tumor or high-grade meningioma from the preoperative radiological findings. CASE DESCRIPTION: A 59-year-old man was admitted to our hospital because of a temporary loss of consciousness. Contrast-enhanced magnetic resonance imaging (MRI) of the brain showed a 30-mm × 12-mm mass located in the right frontal convexity. The lesion had an isointensity to high-intensity signal with moderate periregional edema on T2-weighted MRI, and homogeneous enhancement, including a necrotic portion with a long dural tail along the right frontal convexity, after contrast-enhanced MRI. Thus, our preliminary diagnosis was high-grade meningioma or a malignant tumor. We decided to surgically remove the tumor. Intraoperatively, the lesion appeared as a dural-based yellowish mass with partial infiltration of the cortex. Histopathological examination of the lesion revealed thickened meninges with marked fibroinflammatory changes. The inflammatory changes extended into the underlying brain parenchyma and were centered in the perivascular spaces. The lesion showed abundant lymphoplasmacytic infiltration with fibrosis. Immunohistochemistry revealed mixed T and B lymphocytes and plasma cells. Only a small number of IgG4-positive cells were identified. From these findings, we finally concluded that the diagnosis was IHP. The patient did not receive any further steroid therapy, because the patient had no evidence of systemic autoimmune disease. A follow-up brain MRI scan was performed 6 month after surgery, which revealed no recurrence of the lesion. CONCLUSIONS: Surgical treatment can be the first treatment option when the lesion is not localized to a critical portion of the brain. Thus, it might be possible to arrive at a definitive diagnosis histologically and determine additional treatment strategies. Also, if the surgeons are confident that the IHP has been removed completely, additional steroid therapy might not be necessary.

Brain pseudotumour secondary to Behçet's disease.

Neuro-Behçet's disease (NBD) is a serious manifestation of Behçet's disease (BD) and can affect either the central or peripheral nervous systems, or both. It occurs in 10-50% of patients with BD. We report on a patient with an unusual intraparenchymal lesion, initially thought to be a brain tumour. Histological examination revealed vasculitis consistent with BD. Clinicians should include NBD as a differential diagnosis when considering an isolated inflammatory intracranial lesion.

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.

BACKGROUND: Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) development (including pseudotumors) secondary to metal debris generation around total hip arthroplasties is a well-recognized histopathologic phenomenon. Emerging data have highlighted a similar potential concern around TKAs although the body-of-knowledge has largely been limited to individual case reports or small retrospective case series. This study sought to establish the prevalence of pseudotumors or high-grade ALVALs seen at the revision of primary TKAs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcome measures. METHODS: The findings of 321 non-infective (aseptic) patients undergoing unilateral revision knee surgery, at a high-volume tertiary referral center, were reviewed. Each case was independently histologically classified. Complete patient-reported functional outcome measures were available for 134 patients (42%) allowing correlation between functional performance and histopathology results. RESULTS: Five distinct pseudotumors and a further 18 high-grade ALVALs were histologically identified representing 1.6% and 5.6% of the cohort, respectively. When compared by histologic grade, Oxford Knee Score and Western Ontario and McMaster University's Osteoarthritis Index suggested a high correlation between ALVAL grade and functional knee scores. CONCLUSION: These findings suggest a prevalence of pseudotumors or high-grade ALVALs at revision TKA surgery of >7%. This unexpectedly high result may contribute insight into the previously under-appreciated significance of metal debris-related local tissue reactions around TKAs. The findings also demonstrate a strong near-linear inverse relationship between patient-reported clinical knee performance and the underlying histologic grade of local tissue reaction. These results have potential management implications for patients with underperforming TKAs and should prompt consideration of an ALVAL secondary to metallosis in the differential diagnosis. LEVEL OF EVIDENCE: This is a retrospective cohort study with Level III evidence.

Selective arterial embolization as neoadjuvant treatment in hip pseudotumors.

OBJECTIVES: This study aims to investigate the significance of selective arterial embolization (SAE) as neoadjuvant for the treatment of pseudotumor (PT) associated with hip arthroplasty and present our case series including all the known bearing techniques. PATIENTS AND METHODS: This retrospective study included 16 patients (9 males, 7 females; mean age 75.5 years; range, 55 to 87 years) affected by hip PT. Seven patients were treated only surgically without any adjuvant treatment (group A), while nine patients were performed preoperative SAE (group B). Pseudotumors were grouped according to magnetic resonance imaging and computed tomography (CT) classifications. Durations of all operations and number of blood units given intra- and postoperatively were recorded. RESULTS: Although embolization did not change the amount of intraoperative bleeding (p=0.619), a common vascular network leading to PT was observed in all patients in angiography. Group A's mean duration of operation was shorter than group B (p=0.03); however, this condition was attributed to larger and more complex lesions of patients who underwent embolization. According to CT classification, blood loss was more and duration of operation was longer in severe stages (p=0.046 and p=0.035, respectively). CONCLUSION: Successful demonstration of vascular network in patients with PT strengthens the idea that SAE technique may be used particularly in severe cases according to CT classification. Our findings suggest that PT may develop in all commonly used bearings.

Trends in total hip arthroplasty.

This article discusses developments in total hip arthroplasty related to the use of highly cross-linked polyethylene (HXLPE) liner material as the new standard of care for acetabular cup articulation surfaces. The pathologic implications of metal-on-metal hip prostheses in asymptomatic patients also are discussed.