Breast filler granuloma mistaken for implant rupture: A case report.

RATIONALE: Breast augmentation is usually performed by inserting implants into the breasts. However, injectable fillers are sometimes used for the convenience of both patients and surgeons. If foreign substances, such as biomaterials, are injected into the body, complications such as inflammation, granuloma, and tissue necrosis can occur owing to foreign body reactions. PATIENT CONCERNS: A 39-year-old female patient visited our hospital complaining of tenderness, redness, and swelling in both breasts. The patient had undergone bilateral breast augmentation using implants 4 years prior to current consult. DIAGNOSES: On magnetic resonance imaging (MRI), cystic lesions and fluid collections were observed, with findings suggesting implant rupture; hence, surgery was planned to remove both implants. INTERVENTIONS: Intraoperatively, the implant was malpositioned in the upper lateral portion without rupture. Capsular contracture findings were also not prominent. A large amount of inflammatory granuloma was observed and removed in the prepectoral plane, and the implants were immediately inserted into a new subpectoral plane. OUTCOMES: The volume of the new implant was 175 mL, which was smaller than the previous one, as per the patient preference. Cytology of the fluid from the previous implant pocket showed no evidence of malignancy, and the granuloma was identified as inflammatory tissue caused by a foreign body reaction on biopsy. The excessive protrusion of both breasts was corrected after surgery, and the patient was satisfied with the aesthetic outcomes without any complications up to 3 months after surgery. LESSONS: The use of injectable fillers for breast augmentation carries the risk of misdiagnosis, and, therefore, surgeons should always exercise caution.

Autoimmunity and hernia mesh: fact or fiction?

BACKGROUND: There is an increasing number of patients following hernia surgery with implanted mesh reporting symptoms that could indicate autoimmune or allergic reactions to mesh. 'Allergy' to metals, various drugs, and chemicals is well recognised. However, hypersensitivity, allergy or autoimmunity caused by surgical mesh has not been proven by a scientific method to date. The aim of this study was twofold: to describe the pathophysiology of autoimmunity and foreign body reaction and to undertake a systematic review of surgical mesh implanted at the time of hernia repair and the subsequent development of autoimmune disease. METHODS: A systematic review using the PRISMA guidelines was undertaken. Pubmed (Medline), Google Scholar and Cochrane databases were searched for all English-written peer-reviewed articles published between 2000 and 2021. The search was performed using the keywords "hernia", "mesh", "autoimmunity", "ASIA", "immune response", "autoimmune response". RESULTS: Seven papers were included in the final analysis-three systematic reviews, three cohort studies and one case report. Much of the current data regarding the association of hernia mesh and autoimmunity relies on retrospective cohort studies and/or case reports with limited availability of cofounding factor data linked to autoimmune disease such as smoking status or indeed a detailed medical history of patients. Three systematic reviews have discussed this topic, each with a slightly different approach and none of them has identified causality between the use of mesh and the subsequent development of autoimmune disease. CONCLUSION: There is little evidence that the use of polypropylene mesh can lead to autoimmunity. A large number of potential triggers of autoimmunity along with the genetic predisposition to autoimmune disease and the commonality of hernia, make a cause and effect difficult to unravel at present. Biomaterials cause foreign body reactions, but a chronic foreign body reaction does not indicate autoimmunity, a common misunderstanding in the literature.

Extensive Foreign Body Reaction to Synthetic Dural Replacement After Decompressive Craniectomy with Radiological and Histopathology Evidence: Observational Case Series.

BACKGROUND: Though the indications are quite varied, decompressive craniectomy is considered a life-saving procedure. Maximal effectiveness of craniectomy is achieved when, in addition to bone removal, the dura mater is opened properly and is augmented with duraplasty. Different synthetic materials have been used over the decades to replace the dura during decompressive craniectomy. We have used different synthetic dural replacements at our institution, including Neuro-Patch, DuraGen, and Lyoplant. In this case series, we described 4 cases that had excessive granulation tissue formation in response to a newly used synthetic dural substitute (ReDura) after emergent decompressive craniectomy. During follow-up brain imaging at different intervals, these cases were found to have foreign body reaction in the form of excessive granulation tissue formation; additionally, 1 case had a sterile pus-like collection. The granulation tissue diagnosis was affirmed by histopathology in all 4 cases. METHODS: This study was an observational retrograde case series, with data obtained from electronic medical records. RESULTS: The study showed extensive foreign body giant cell reactions on preoperative computed tomography scans, indicating a very high occurrence rate of 72.4%, when ReDura was used as dural replacement. CONCLUSIONS: Our experience showed that patients are prone to develop severe foreign body giant cell reactions with ReDura. Neurosurgical centers using this material should monitor patients for possible abnormal foreign body reaction and report it to establish the safety and efficacy profile of this material.

Massive foreign body reaction and osteolysis following primary anterior cruciate ligament reconstruction with the ligament augmentation and reconstruction system (LARS): a case report with histopathological and physicochemical analysis.

BACKGROUND: Autologous hamstrings and patellar tendon have historically been considered the gold standard grafts for anterior cruciate ligament reconstruction (ACLR). In the last decades, the utilization of synthetic grafts has re-emerged due to advantageous lack of donor site morbidity and more rapid return to sport. The Ligament Augmentation and Reconstruction System (LARS) has demonstrated to be a valid and safe option for ACLR in the short term. However, recent studies have pointed out the notable frequency of associated complications, including synovitis, mechanical failure, and even chondrolysis requiring joint replacement. CASE PRESENTATION: We report the case of a 23-year-old male who developed a serious foreign body reaction with wide osteolysis of both femoral and tibial tunnels following ACLR with LARS. During first-stage arthroscopy, we performed a debridement of the pseudocystic mass incorporating the anterior cruciate ligament (ACL) and extending towards the tunnels, which were filled with autologous anterior iliac crest bone graft chips. Histological analysis revealed the presence of chronic inflammation, fibrosis, and foreign body giant cells with synthetic fiber inclusions. Furthermore, physicochemical analysis showed signs of fiber depolymerization, increased crystallinity and formation of lipid peroxidation-derived aldehydes, which indicate mechanical aging and instability of the graft. After 8 months, revision surgery was performed and ACL revision surgery with autologous hamstrings was successfully carried out. CONCLUSIONS: The use of the LARS grafts for ACLR should be cautiously contemplated considering the high risk of complications and early failure.

Clinical Features and Treatment of Intra-Tendinous Suture Reaction Following Achilles Tendon Repair Using Nonabsorbable Suture Material: A Retrospective Case Series Study.

We aimed to investigate the clinical manifestations, radiological findings, and therapeutic outcome of treatment for patients with surgically confirmed foreign body reaction following an Achilles tendon repair using non-absorbable suture material. Eight consecutive patients who were confirmed as having an intra-tendinous suture foreign body reaction in the histopathological report were enrolled in this study. Medical records of all patients in terms of clinical and radiological features were retrieved. Also, the outcome of treatment was evaluated at a follow-up of at least 12 months. All the patients complained of pain and a palpable mass around a previous surgical site at mean 25.1 months (range, 4-72 months) after the initial surgery. Magnetic resonance imaging (MRI) or ultrasound were used to detect the lesion. All the patients underwent surgical excision of foreign body reaction tissue and primary repair using absorbable suture material. After the treatment, the wounds were healed completely in all, and the average FAOS (foot and ankle outcome score) was 91.32 at mean follow-up for 22.4 months. In conclusion, intra-tendinous suture reaction is a rare complication following an Achilles tendon repair using nonabsorbable suture material, but it can be treated adequately with only surgical excision of foreign body reaction tissue and primary repair using absorbable suture material.

Foreign Body Reaction Following Use of a Novel Bone Graft Substitute in Pediatric Cranioplasty.

ABSTRACT: Pediatric cranioplasty is indicated to repair skull defects with a wide variety of etiologies. The choice of graft material used to fill the defect is of paramount importance to the long-term success of this procedure. A variety of synthetic products have been commercially developed to avoid donor site morbidity. Here, the authors present the case of a 13-year-old boy with cranial Langerhans cell histiocytosis who underwent cranioplasty with a novel, calcium phosphate-based bone graft substitute (Montage). The patient presented 2 years postoperatively with a foreign body giant cell reaction that required explantation of the graft. The authors discuss potential considerations in choosing the most appropriate graft, potential contributors to this late adverse outcome, and the need for further research into the use of novel allograft materials in pediatric cranioplasty.

Clinical and radiological comparison of bioactive glass and poly-L-lactic acid/hydroxyapatite bioabsorbable interference screws for tibial graft fixation in anterior cruciate ligament reconstruction.

BACKGROUND: Ligament reconstruction is still the main treatment modality for patients with a complete ligament rupture. The semitendinosus tendon, alone quadrupled or double folded and combined with the gracilis tendon, is still the most frequently used autologous graft for a reconstructive procedure. Absorbable interference screw usage has gained popularity in the past decade because they create less artifacts during MR imaging and tend to osteointegrate over the years, arguably leading to a more anatomic fixation. The purpose of this study was to compare the 5-year radiological and clinical results of two different tibial graft fixation screws. HYPOTHESIS: We hypothesized that bioabsorbable interference screws made of bioactive glass would lead to higher rates of osteointegration, better overall clinical results, less foreign body reaction rates and less tibial tunnel widening when compared to the poly-L-lactic acid/hydroxyapatite (PLLA-HA) screws. PATIENTS AND METHODS: Fifty-one patients treated with an anatomic single bundle ACL reconstruction between June 2015 and July 2016 at our institution were included in the study. The tibial graft was fixed with a bioactive glass screw in 24, and with a PLLA-HA in 27 patients. Tibial tunnel widening, foreign body reaction, osteointegration and resorption rates were evaluated and compared on a magnetic resonance scan at a minimum of 5 year postoperatively. Overall clinical results and side-to-side difference on KT-1000 were also analyzed in-between groups. RESULTS: Tibial tunnel widening was similar for both groups. Foreign body reaction, while not statistically significant, was less aggressive when bioactive glass screws were used. Osteointegration and resorption rates of the bioactive glass screws were significantly higher than the PLLA-HA group (p=0.000). While all patients showed an overall improvement on postoperative scores (p=0.000), patients with a bioactive glass interference screw had statistically higher translational stability with KT-1000, compared to the poly-L-lactic acid/hydroxyapatite group (p=0.001). DISCUSSION: At a minimum of 5 years, compared to conventional PLLA-HA interference screws, 45S5 bioactive glass screw provide higher resorption rates, are more highly biodegradable and provide overall good clinical results. LEVEL OF EVIDENCE: III.

A case of disintegrated Strattice™ 4 years after immediate breast reconstruction.

Acellular dermal matrices (ADMs) are used frequently in immediate breast reconstruction (IBR). In general, the porcine-derived ADM Strattice™ has been reported with good outcomes and low complication rates. Nonetheless, we report here a case of a 42-year-old, otherwise healthy woman with a history of uncomplicated bilateral prophylactic nipple-sparing mastectomies and subpectoral IBRs performed using Strattice™ and Mentor® CPG™, who was referred to the Department of Plastic Surgery 4 years after this surgery due to changed appearance of her breast implants. Both CPG implants were found intact and there were no signs of infection but, surprisingly, the Strattice™ had completely disintegrated on both sides. Examinations did not show any malignancies, and at 1-year clinical follow-up, the patient had no signs of relapse. Thus, we suggest that the Strattice™ had disintegrated as a late aseptic foreign body reaction and emphasise the importance of surgeons being aware of this late and rare complication.

Arthroscopy-Assisted Treatment of Wear Debris Pseudotumor After Total Knee Arthroplasty: A Case Report.

BACKGROUND: Wear debris pseudotumors are a rare complication after total knee arthroplasty (TKA) and have seldom been reported in the recent literature. There is no consensus on the best therapeutic method, but the high quality curative treatment, safe, low invasive treatments are required for the patients. CASE PRESENTATION: In this paper, we present the case of a 74-year-old man with a wear debris pseudotumor after TKA with symptoms of severe pain and functional disability of his right knee. X-ray examination showed that the medial compartment of the right knee was narrowing. Magnetic resonance imaging (MRI) and Doppler ultrasound both revealed a polycystic mass at the posteromedial side of the patient's right knee. Considering the bad health condition and the minimally invasive surgery requirement of this senior patient, arthroscopic knee debridement and percutaneous cystic mass suction were carried out simultaneously. Video arthroscopy of the right knee showed visible inflammatory soft tissue, obvious polyethylene fragments, wear of the polyethylene prothesis, and a broken polyethylene insert. The intraarticular polyethylene wear debris was removed as much as possible, and inflammatory soft tissue was debrided and sent for pathology. Postoperative pathology showed polyethylene debris in the soft tissue with an apparent multinucleated giant cell response, which was consistent with foreign body granuloma. All clinical manifestation was improved and Lysholm scores were significantly better at one year with this treatment, increasing from 32 points to 71 points. CONCLUSION: After two years of follow-up, the patient's knee joint was significantly relieved from soreness and pain, and walking was not significantly restricted. Our treatment could not address the root cause of the wear debris pseudotumor, which was due to prosthesis failure, but sometimes, such an approach is the safest, most economical, and most effective choice for patients who are intolerant to reoperation.

Cutaneous foreign body microemboli-induced occlusive vasculopathy: A complication of illicit intravenous injection of oral opioid tablets.

Occlusive nonvasculitic vasculopathy is a process characterized clinically by retiform purpura and potential ulceration and necrosis of affected areas, secondary to blockage of small vessels without associated inflammatory vasculitis. Intravascular injection of foreign material is known to cause distal ischemia and necrosis due to thrombosis, local vasoconstriction, or microemboli formation. A 27-year-old male presented with retiform purpura and worsening distal fingertip necrosis of the right upper extremity accompanied by suspicious intravascular polarizable foreign material identified on skin, muscle, and vascular biopsies. We report a case that highlights concerning complications and dermatopathologic findings of intravascular injection of oral opioid tablets.

Heel Complications.

Postoperative complications can be burdensome on both the patient and the surgeon. Attention in literature is often directed toward different forms of treatment and successful outcomes in surgery. The incentive of this article is to bring insight toward postoperative complications in rearfoot surgery, more specifically, the repair of the Achilles tendon with suture tape and suture anchors. This article directs attention to the recent reports on hypersensitivity reactions seen with the use of suture tape and nonabsorbable suture anchors and may encourage physicians to make patients aware of this potential complication when using these materials.

Lipofilling after Laser-Assisted Treatment for Facial Filler Complication: Volumetric and Regenerative Effect.

BACKGROUND: Nonresorbable substances are still injected to enhance soft-tissue volumes and fill subcutaneous defects. The minimally invasive intralesional laser treatment can remove foreign substances and the inflammatory reaction, eventually leaving depression and scar tissue in the treated area. Fat grafting can restore volume loss and improve scar tissue. METHODS: From March of 2010 to February of 2017, 33 patients were studied. All of them had suffered from inflammatory reactions to permanent facial fillers and had been treated with the 808-nm diode laser at the authors' institution. The evacuation of material had left facial asymmetry and visible depression. To restore facial aesthetic units, fat grafting was performed. The minimum follow-up was 6 months. RESULTS: Volume restoration was recognized (according to the Global Aesthetic Improvement Scale) as significantly improved in 22 patients, moderately improved in eight patients, and slightly improved in three patients. Improvement in atrophic and scarred tissues (with an apparent thickening of the skin or even elimination of scars) was also assessed with the following results: 25 patients were very much improved and eight were moderately improved. CONCLUSIONS: This is the first study on filler-induced complications of the face treated by intralesional laser treatment followed by lipofilling. A systematic approach to volume restoration is proposed to patients who had filler removal of the face. There was a high degree of patient satisfaction with this technique. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Rectal Perforation by an Intrauterine Device Leading to Fatal Intra-Abdominal Sepsis and Necrotizing Fasciitis.

BACKGROUND: Colorectal injury from an intrauterine device (IUD) is rare but may lead to major complications. CASE: A 55-year-old woman presented to a tertiary care hospital with 4 days of generalized weakness, confusion, dysuria, and lower back pain. She provided a vague history of an unsuccessful attempt to remove an IUD 30 years prior. A computed tomography scan demonstrated an IUD in the rectal lumen, with gluteal and pelvic gas and fluid collections. Emergency surgery found necrotizing fasciitis. Despite multiple debridements, sigmoidoscopic IUD removal, and long-term intravenous antibiotics, the patient died from sepsis and multiorgan failure. CONCLUSION: IUDs require proper monitoring and timely removal to prevent potential complications associated with organ perforation.

Symptomatic intracranial embolic foreign-body reactions after endovascular neurointerventional procedures: A retrospective study in a tertiary hospital.

INTRODUCTION: Polymer-coats may peel-off the surface of catheters and devices during endovascular procedures and might lead to brain inflammatory foreign-body reactions. METHODS: We conducted a retrospective, descriptive, single-centre study including all patients with symptomatic intracranial oedematous and contrast-enhancing lesions after any neurointerventional procedure performed in our hospital between 2013 and 2019. RESULTS: From a total of 7446 neurointerventional procedures, 11 cases were identified (9 female, 2 male, median age 47 year-old), with an incidence of 0.14 %. The procedures were therapeutic in all: ten aneurysm embolization/isolation, one acute ischaemic stroke recanalization. Intracranial coils, stent or both were placed in all. Symptoms appeared during the following one day to fourteen months (median of 4.2 weeks). Brain MRI showed oedematous, contrast-enhancing lesions scattered through the vascular territory of the canalized vessel. Brain biopsy confirmed the diagnosis in one case and was supportive in another one. Eight patients received immunosuppression. No treatment was started in two. After a median time of follow-up of 3.5 years, five patients are totally asymptomatic. One patient presents slight weakness. Four patients have remote symptomatic seizures, but they have comorbid lesions (previous stroke, intracranial haemorrhage, biopsy needle-track's gliosis). Follow-up MRI showed significant improvement in all the cases, with complete resolution in five. Non-symptomatic lesion fluctuation was observed in three cases. Two patients experienced symptomatic rebounds. CONCLUSION: Intracranial embolic foreign-body symptomatic reactions are uncommon complications of neurointerventional procedures. Diagnostic angiographies might have lower risk of polymer-embolization than therapeutic procedures. This entity's early recognition enables making proper diagnosis and treatment decisions.

Breast reconstruction after complications following breast augmentation with massive filler injections.

INTRODUCTION: Breast filler injections are less commonly used due to their associated complications, such as pain and foreign body reactions. Yet, these fillers are often administered illegally, resulting in aesthetic or life-threatening complications. These are treated by removing the foreign material, and the breasts are reconstructed using silicone implants or autologous tissue/fat injection. PATIENT CONCERNS: Case 1. A 45-year-old woman with polyacrylamide gel injections in both breasts visited our clinic for breast pain and tenderness. Grade I ptosis was observed in each breast, without skin necrosis and discoloration. Case 2. A 51-year-old woman, with unknown breast filler injections, visited our clinic for painful masses. Intraoperatively, massive amounts of foreign material had severely infiltrated the nearby tissues; thus, an immediate breast reconstruction could not be performed. Three months later, severe deformities including shrinkage and irregular breast skin surfaces were observed. DIAGNOSIS: Case 1. Multiple cystic lesions, fluid collection in the retromammary spaces, and diffuse infiltration were observed on mammography, computed tomography, and ultrasonography. Case 2. Multiple cystic lesions, calcified areas, and diffuse infiltrations in the axillae and retromammary spaces were observed on mammography, computed tomography, and ultrasonography. INTERVENTIONS: Case 1. The foreign material was removed and the breasts were reconstructed using silicone implants into subpectoral pocket with acellular dermal matrices (Alloderm, Lipocell Corporation). Case 2. A delayed reconstruction was undertaken using silicone implants covered by latissimus dorsi muscle flaps, 3 months after the foreign material removal. OUTCOMES: Case 1. The foreign material was removed and there were no complications such as foreign body reaction, capsular contracture. Ptosis was corrected and both breasts were symmetric with proper projection. Case 2. Residual foreign material was removed and there were no complications such capsular contracture, implant malposition. CONCLUSION: Massive injections of foreign materials into the breast can cause severe infiltration and associated foreign body reactions. By a near-complete removal of the foreign materials and breast reconstruction using silicone implants, we achieved satisfactory results, without complications such as wound disruption, capsular contracture, and implant malposition.

Computed Tomography Findings in Vernix Caseosa Peritonitis.

INTRODUCTION: Vernix caseosa peritonitis (VCP) is a rare peripartum complication secondary to the introduction of fetal vernix into the maternal peritoneal cavity. Vernix caseosa peritonitis typically manifests a few hours to days after a cesarian section and is often initially misdiagnosed as a more common disease process resulting in delayed diagnosis. We report the computed tomography (CT) findings in 2 patients with VCP and reviewed the previously reported CT findings of VCP. CASES: Two patients, aged 17 and 24 years, presented with signs and symptoms of peritonitis within days of undergoing a cesarian section. In both cases, CT scans of the abdomen and pelvis demonstrated ascites and multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules which were most prominent around the liver and became larger and more numerous over time. Antibiotic therapy was not effective, subsequent laparoscopic peritoneal biopsy demonstrated VCP, and patients were successfully treated with lavage and the addition of intravenous steroids. CONCLUSIONS: Vernix caseosa peritonitis is an underrecognized disorder that is most often mistaken for other more common causes of peritonitis. In the setting of peripartum peritonitis, the CT findings of ascites with multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules, especially adjacent to the liver, which grow in size and number strongly suggests VCP.

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.

[A case of human adjuvant disease with clinical features of Guillain-Barré syndrome].

A 69-year-old female developed subacute diplopia, right peripheral facial nerve palsy, bilateral upper and lower extremities dysesthesia and weakness 50 years after silicone injection for breast augmentation. Motor conduction study revealed prolonged distal latency and reduced amplitude in the median, ulnar, and peroneal nerves. Sensory conduction velocities were reduced in the median and ulnar nerves, and sensory potential in the sural nerve could not be recorded. While intravenous immunoglobulin therapy was ineffective, explantation of silicone breast implants improved her neurological symptoms. Histopathological study of axillary lymph node revealed foreign body granulomas and macrophages phagocyting silicone. The patient was diagnosed with human adjuvant disease presenting clinical features of Guillain-Barré syndrome. Human adjuvant disease should be considered in the patients with implants like silicone and neurological symptoms.

What Is the Risk of THA Revision for ARMD in Patients with Non-metal-on-metal Bearings? A Study from the Australian National Joint Replacement Registry.

BACKGROUND: There are increasing reports of corrosion between the femoral head and trunnion in primary conventional THA, resulting in metal particulate release often termed trunnionosis. There may be heightened awareness of this condition because of severe soft-tissue reactions initially thought to be solely attributable to prostheses with a metal-on-metal (MoM) bearing surface. It is unclear what percentage of revisions for THA with non-MoM bearing surfaces can be attributed to trunnionosis and to what extent adverse reaction to metal debris (ARMD) seen with MoM bearings may also be seen with other bearing surfaces in THA. QUESTIONS/PURPOSES: We analyzed data from a large national registry to ask: (1) What is the revision risk for the indication of ARMD in patients with conventional THA and modern non-MoM bearing surfaces such as metal or ceramic-on-cross-linked polyethylene (XLPE) or ceramic-on-ceramic? (2) What prosthesis factors are associated with an increased risk of such revision? (3) What is the relative revision risk for ARMD in THAs with large-head MoM bearings, small-head MoM bearings, and non-MoM modern bearing surfaces? METHODS: The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) longitudinally maintains data on all primary and revision joint arthroplasties, with nearly 100% capture. The study population included all THAs using modern bearing surfaces (defined as metal or ceramic heads-on-XLPE and ceramic-on-ceramic bearing couples) revised because of ARMD between September 1999 and December 2018. Prostheses with modular necks were excluded. The cumulative percent revision (CPR) because of ARMD was determined. The study group consisted of 350,027 THAs with a modern bearing surface, 15,184 THAs with a large-head MoM bearing (≥ 36 mm), and 5474 THAs with a small head MoM bearing (≤ 32 mm). The patients in the group who received the modern bearing surfaces were slightly older than the patients in the groups who received the large- and small-head bearing surfaces, with a mean age 68 years (SD 12) versus a mean age 63 years (SD 12), and a mean age 62 years (SD 11), respectively. There was a higher proportion of women in the modern bearing surface group; 55% (193,312 of 350,027), compared with 43% (6497 of 15,184) in the large-head MoM group and 50% (2716 of 5474) in the small-head MoM group. The outcome measure was the CPR, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the first revision for ARMD at 17 years. Hazard ratios (HR) from Cox proportional hazards models, adjusting for age and sex, were performed to compare the revision rates among groups. The registry defines a revision as a reoperation of a previous hip arthroplasty in which one or more of the prosthetic components is replaced or removed, or one or more components is added. RESULTS: The CPR for ARMD for patients with a modern bearing surface at 17 years was 0.1% (95% confidence interval 0.0 to 0.1). After controlling for age and sex, we found that cobalt chrome heads, two specific prostheses (Accolade® I and M/L Taper), and head sizes ≥ 36 mm were associated with an increased risk of revision for ARMD. Metal-on-XLPE had a higher risk of revision for ARMD than ceramic-on-ceramic or ceramic-on-XLPE (HR 3.4 [95% CI 1.9 to 6.0]; p < 0.001). The Accolade 1 and the M/L Taper stems had a higher risk of revision than all other stems (HR, 8.3 [95% CI 4.7 to 14.7]; p < 0.001 and HR 14.4 [95% CI 6.0 to 34.6]; p < 0.001, respectively). Femoral stems with head sizes ≥ 36 mm had a higher rate of revision for ARMD than stems with head sizes ≤ 32 mm (HR 3.2 [95% CI 1.9 to 5.3]; p < 0.001).Large-head MoM bearings had a greater increase in revision for ARMD compared with modern bearing surfaces. The CPR for patients with a large-head MoM bearing at 17 years for ARMD was 15.5% (95% CI 14.5 to 16.6) and it was 0.1% for modern bearing surfaces (HR 340 [95% CI 264.2 to 438.0]; p < 0.001). Modern bearing surfaces likewise had a lower HR for revision for ARMD than did THAs with small-head MoM bearings, which had a 0.9% (95% CI 0.7 to 1.4) CPR compared with modern bearings from 0 to 9 years (HR 10.5 [95% CI 6.2 to 17.7]; p < 0.001). CONCLUSIONS: The revision risk for ARMD with modern bearing surfaces in THA is low. The Accolade 1 and the M/L Taper stem have a higher risk of revision for ARMD and cobalt-chrome heads, and head sizes ≥ 36 mm have a higher rate of revision than ≤ 32 mm head sizes. ARMD is a rare failure mode for THA with non-MoM bearings, but in patients presenting with unexplained pain with no other obvious cause, this diagnosis should be considered and investigated further. LEVEL OF EVIDENCE: Level III, therapeutic study.

Has the threshold for revision surgery for adverse reactions to metal debris changed in metal-on-metal hip arthroplasty patients? A cohort study of 239 patients using an adapted risk-stratification algorithm.

Background and purpose - A risk-stratification algorithm for metal-on-metal hip arthroplasty (MoMHA) patients was devised by US experts to help clinicians make management decisions. However, the proposed algorithm did not cover all potential patient or surgical abnormalities. Therefore we adapted the US risk-stratification algorithm in MoMHA patients revised for adverse reactions to metal debris (ARMD) to determine the variability in the revision threshold, and also whether high-risk patients had inferior outcomes following revision.Patients and methods - We analysed 239 MoMHA revisions for ARMD between 2001 and 2016 from 2 centres with pre-revision blood metal ions and imaging. Patients were stratified (low risk, moderate risk, high risk) using pre-revision factors (implant, radiographic, blood metal ions, cross-sectional imaging) by adapting a published algorithm. The risk categories for each factor were assessed against revision year, revision centre, and post-revision outcomes (re-revision surgery, and any poor outcome).Results - Compared with hips revised before 2012, hips revised from 2012 onwards included more high-risk implants (44% vs. 17% pre-2012), high-risk radiographic features (85% vs. 69% pre-2012), and low-risk metal ions (41% vs. 19% pre-2012). 1 centre more frequently revised patients with high-risk implants (48% vs. 14%) and low-risk blood metal ions (45% vs. 15%) compared with the other. All these comparisons were statistically significant (p < 0.05). With the limited sample size available, implant, radiographic, blood metal ion, and cross-sectional imaging risk groups did not statistically significantly affect the rates of re-revision surgery or frequency of poor outcomes post-revision.Interpretation - When applying the adapted risk-stratification algorithm the threshold for ARMD revision changed over time, presumably due to increasing evidence, patient surveillance, and investigation since 2012. Lower blood metal ion thresholds were used from 2012 for ARMD revisions; however, there was evidence that centres attached different importance to metal ions when managing patients. High-risk patients did not have inferior outcomes following ARMD revision.