Previous reports on the outcomes of isolated head and liner exchange in revision total hip arthroplasty have found high rates of instability following these surgeries. Most reports have studied constructs using ≤28mm femoral heads. The purpose of this study was to determine if modern techniques with the use of larger head sizes can improve the rate of instability after head and liner exchange. We identified 138 hips in 132 patients who underwent isolated head and liner exchange for polyethylene wear/osteolysis (57%), acute infection (27%), metallosis (13%), or other (2%). All patients underwent revision with either 32mm (23%), 36mm (62%), or 40mm (15%) diameter heads. Crosslinked polyethylene was used in all revisions. Lipped and/or offset liners were used in 104 (75%) hips. Average follow up was 3.5 (1.0–9.1) years. Statistical analyses were performed with significance set at p<0.05. Revision-free survivorship for any cause was 94.6% and for aseptic causes was 98.2% at 5 years. 11 (8%) hips experienced a complication with 7 (5%) hips requiring additional revision surgery. Following revision, 4 (3%) hips experienced dislocation, 5 (4%) hips experienced infection, and 1 (1%) hip was revised for trunnionosis. No demographic or surgical factors significantly affected outcomes. Our study shows that isolated head and liner exchange using large femoral heads and modern liners provides for better stability than previous reports. The most common complication was infection. We did not identify specific patient, surgical or implant factors that reduced the risk of instability or other complication

Mechanical irritation or impingement of the iliopsoas tendon accounts for 2–6% of persistent postoperative pain cases after total hip arthroplasty (THA). The most common trigger is anterior cup overhang. CT-scan can be used to identify and measure this overhang; however, no threshold exists for symptomatic anterior iliopsoas impingement. We conducted a case–control study in which CT-scan was used to define a threshold that differentiates patients with iliopsoas impingement from asymptomatic patients after THA. We analyzed the CT-scans of 622 patients (758 CT-scans) between 2011 and 2020. Out of this population we identified 136 patients with symptoms suggestive of iliopsoas impingement. Among them, 6 were subsequently excluded: three because the diagnosis was reestablished intra-operatively (one metallosis, two anterior instability related to posterior prosthetic impingement) and three because they had another obvious cause of impingement (one protruding screw, one protruding cement plug, one stem collar), leaving 130 patients in the study (impingement) group. They were matched to a control group of 138 patients who were asymptomatic after THA. The anterior cup overhang (anterior margin of cup not covered by anterior wall) was measured by an observer (without knowledge of the clinical status) on an axial CT slice based on anatomical landmarks (orthogonal to pelvic axis). The impingement group had a median overhang of 8 mm [IQR: 5 to 11] versus 0 mm [IQR: 0 to 4] for the control group (p<.001). Using ROC curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%, PPV = 75%, NPV = 85%). Pain after THA related to iliopsoas impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of iliopsoas irritation or another reason for the pain after THA before concluding impingement is present

Ceramic-on-ceramic (CoC) articulations in total hip arthroplasty (THA) have low wear, but the unique risk of fracture. After revision for CoC fracture, ceramic third bodies can lead to runaway wear of cobalt chrome (CoCr) causing extremely elevated blood cobalt. We present five cases of ceramic liner fractures revised to a CoCr head associated with the rapid development of severe cobalt toxicity. We identified 5 cases of fractured CoC THA treated with revision to CoCr on highly cross-linked polyethylene (HXLPE) – three to conventional bearings and two to modular dual mobility bearings (CoCr acetabular liner, CoCr femoral head, and HXLPE). Mean follow up was 2.5 years after CoCr/HXLPE re-revision. Symptoms of cobalt toxicity occurred at average 9.5 months after revision for ceramic fracture (range 6–12). All patients developed vision and hearing loss, balance difficulties, and peripheral neuropathy. Several had cardiomyopathy, endocrinopathy, and local skin discoloration. Two reported hip pain. Re-revision for cobalt toxicity occurred at an average of 22 months (range 10–36) after revision for ceramic fracture. Average serum cobalt level at re-revision was 991 μg/L (range 734–1302, normal <1 μg/L). All CoCr heads exhibited massive wear with asphericity; deep tissues exhibited prominent metallosis. Treatment consisted of debridement and revision to a ceramic head with HXLPE. Serum cobalt improved to an average of 25 μg/L at final follow up. All patients reported partial improvement in vision and hearing; peripheral neuropathy and balance did not recover. Systemic cobalt toxicity is a rare but devastating complication of ceramic fracture in THA treated with cobalt-alloy bearings. Cobalt alloy bearings should be avoided in this setting. The diagnosis of systemic cobalt toxicity requires a high index of suspicion and was typically delayed following systemic symptoms. Debridement and revision to a ceramic-on-HXLPE leads to improvement but not resolution of cobalt toxicity complications

Pre-operative definitive diagnosis of infection in painful total hip arthroplasty (THA) is not always easy to be established, making the intra-operative decision-making process crucial in management of revision hip surgery. Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJIs. From November 2020 to December 2022, 105 patients with painful primary THA were treated with revision THA in 3 orthopaedic departments. Pre-operatively, 23 were considered infected and treated with two-stage revision THA. The remaining 82 were likely infected according to the 2019 EBJIS criteria. The suspicion of low-grade infection was based on clinical (rest and/or night pain), laboratory (CRP, ESR, WBC – normal or slightly elevated) and radiological evaluation (loosening). Hip aspiration under CT imaging was performed in these cases and 34 of them yielded positive culture and were treated with two-stage revision. Aspiration was ineffective in the remaining 48 cases (33 negative, 15 unsuccessful attempts). Intra-operatively, calprotectin was measured with lateral flow immunoassay test in these patients. Cases with calprotectin levels ≥ 50 mg/L were treated with 2-stage revision THA; otherwise, they were considered not-infected and one-stage revision was performed. Synovial fluid and tissue samples were collected for analysis. Implants were sent for sonication fluid cultures. Calprotectin was positive (≥ 50 mg/L) in 27 cases and negative in 21 cases. There was 1 false negative case with positive tissue cultures. Out of the 27 positive cases, 25 had positive tissue cultures and sonication. However, 2 cases with high calprotectin levels (>200 mg/L) were not infected. The false positive result was attributed to severe metallosis. Calprotectin sensitivity was 96.2%, specificity 90.9%, PPV 92.6%, NPV 95.2%, AUC 0.935. The results of this ongoing study indicate that calprotectin seems to be a valuable tool in facilitating the intra-operative decision-making process in cases that low-grade infection is suspected and diagnosis cannot be established pre-operatively

Aims: In vitro studies have demonstrated that phagocytosed metal wear particles can lead to osteolysis by osteoclast activation. While others have reported massive metallosis with no loosening of the implant. The incidence of metallosis has remained uncertain so far. The purpose of this prospective study was to assess the incidence of metallosis and explore the correlation between metallosis and the time to revision of total hip replacements, getting additional information of the role of metallosis in aseptic loosening. Materials and Methods: 72 patients underwent revision of total hip arthroplasty at the authors department from 01/01/2001 to 31/12/2002. All of them were examined for metallosis macroscopically and biopsy was taken from the interfacial membrane for histological analysis. Two subgroups were created from revisions of both cemented and uncemented prostheses. First group was composed of cases if metallosis was either visible during the surgery or high amount of metal particles were found by histology (high-grade metallosis). The other group consisted of cases if metallosis was not visible intraoperatively and only a few metal particles were described by histology (low-grade metallosis). The survivorships of the prostheses were assessed by Kaplan-Meyer statistic analysis. Results: High-grade metallosis could be detected in 10/42 revisions of cemented (23.8%), and in 12/30 cases of uncemented prostheses(40%). The time from implantation to revision was 88(36–144) months when metal-losis could be observed vs. 122(41–360) months in cases with no metallosis in the cemented group. However there was not significant difference in survival rate of the uncemented prostheses between the metallotic and non-metallotic groups. If only very few metal particles were found, high amount of polyethylene particles were described by histology. Conclusion: The incidence of high-grade metallosis was higher around uncemented prostheses. The time to revision of cemented prostheses was significantly less if high-grade metallosis was found. Hence it seems like metallosis can have effect on aseptic loosening of cemented prostheses by the large number of metal particles which can make the progress of osteolysis faster resulting in shorter survivorship of the implant. If no high-grade metallosis, but a lot of polyethylene wear were found, then those particles could have the same inductive effect on aseptic loosening

Purpose: Although hip prosthesis heads made of titanium are no longer implanted to our knowledge, it is important to officially record the failures related to their use. Device monitoring experts can only prove the hazard resulting from these implants if results of human clinical series have clearly described the inconveniences. We found a rich body of literature dating from the end of the eighties that concluded that the rate of wear with the polyethylene lined titanium implants was very low but have found no paper describing the problems related to its use. We report this work to fill the gap. Material and methods: This prospective study included a consecutive series of the first 100 total hip prostheses using the ion-implanted titanium 22.2 mm head (NITRU-VID) implanted between January 30, 1990 and June 19, 1991. There were 45 men and 55 women, 55 right hips and 45 left hips implanted for primary degenerative disease in 92, dysplasia in two and congenital dislocation in six. Mean age at implantation was 60 years (28–82). The same operative technique was used for all patients using the same Atlas-PSM implant. Eleven patients died and six were lost to follow-up. Thus 83 ere retained for analysis with the Postel-Merle-d’Aubigné (PMA) score on the AP and lateral views of the hip. Kaplan-Meier survival curves were established. Results: Eleven patients underwent revision surgery for different causes, metallosis in seven. The delay to revision for metallosis was eight years in two, nine years in one and ten years in four. These cases of metallosis were expressed clinically by moderate pain and minimal radiographic signs: bone defect in the greater trochanter in seven, acetabular lines in three. Four cups loosened, none of the femur components. The diagnosis of metallosis was made at revision in five cases, and on the basis of hip biopsy in two. Metallosis was intense with black coloration of all the tissues. Pathology confirmed the diagnosis; the head were depolished with wear of the upper pole and loss of spherical shape as verified in the laboratory. The 10-year survival was 91.33%. For the 72 patients who did not have revision surgery, only nine still had moderate pain and four limped. There were eleven cases with trochanteric defects in zone 3 requiring close follow-up as this can be an early sign of metallosis. Discussion: This study proves that despite the ion-implantation, the heads wear and lead to metallosis. No metallosis was observed when using the same implants with different heads at a maximal follow-up of 14 years. In an earlier study on the first 100 implants of this type, the 10-year survival was 98.7%. The drop in the 10-year survival from 98.7 to 91.33% can only be explained by the ion-implanted titanium heads. Conclusions: Ion-implanted titanium heads wear and lead to metallosis. Their use is formally contraindicated. Hip biopsy can provide early diagnosis of metallosis

Aim. To analyse the prevalence of culture negative periprosthetic joint infections (PJI) when adequate culture techniques are applied, and to evaluate the outcome of patients who were treated with antibiotics for a culture negative PJI versus those in whom treatment was withheld. Method. A multicenter observational study in which acute and chronic PJIs diagnosed between 2013 and 2018 were analyzed. Culture negative PJIs were diagnosed according to the MSIS, ICM and EBJIS definitions. Results. Out of the 1553 acute PJIs, none were culture negative. Out of the 1556 chronic PJIs, 70 were culture negative (4.7%) and included for further analysis. A total of 36 were treated with antibiotics (51%). After two years of follow-up, no infections occurred in patients in whom antibiotic treatment was withheld, but prosthesis extraction by any cause was observed more often in the no antibiotic group compared to the antibiotic group (32.4% versus 8.3%, P 0.012), especially in the absence of metallosis. Antibiotic treatment was the only independent predictor of prosthesis retention in the multivariate analysis (95% CI 0.15, 0.03 – 0.70). Conclusions. When adequate culture techniques are applied, the incidence of culture negative PJIs is low. If diagnosed, antibiotic treatment should be administered

Aim. Diagnosing periprosthetic joint infection after total joint arthroplasty is often challenging. The alpha defensin test has been recently reported as a promising diagnostic test for periprosthetic joint infection. The goal of this study was to determine the diagnostic accuracy of alpha defensin testing. Method. One hundred and eighty-three synovial alpha defensin and synovial fluid C-reactive protein (CRP) tests performed in 183 patients undergoing evaluation for periprosthetic joint infection were reviewed. Results were compared with the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection. Results. Alpha defensin tests were performed prior to surgical treatment for infection, and 37 of these patients who had these tests were diagnosed by MSIS criteria as having infections. Among this group, the alpha defensin test had a sensitivity of 81.1% (95% confidence interval [CI], 64.8% to 92.0%) and a specificity of 95.9% (95% CI, 91.3% to 98.5%). There were 6 false-positive results, 4 of which were associated with metallosis. There were 7 false negatives, all of which were associated with either draining sinuses (n = 3) or low-virulence organisms (n = 4). A combined analysis of alpha defensin and synovial fluid CRP tests was performed in which a positive result was represented by a positive alpha defensin test and a positive synovial fluid CRP test (n = 28). Among this group, the sensitivity was calculated to be 73.0% (95% CI, 55.9% to 86.2%) and the specificity was calculated to be 99.3% (95% CI, 96.2% to 99.9%). An additional combined analysis was performed where a positive result was represented by a positive alpha defensin test or positive synovial fluid CRP test (n = 64). Among this group, the sensitivity was calculated tobe91.9%(95%CI, 78.1%to98.3%) andthe specificitywas calculated tobe79.5%(95%CI, 72.0%to85.7%). Conclusions. Alpha defensin in combination with synovial fluid CRP demonstrates very high sensitivity for diagnosing periprosthetic joint infection, but may yield false-positive results in the presence of metallosis or false-negative results in the presence of low-virulence organisms. When both alpha defensin and synovial fluid CRP tests are positive, there is a very high specificity for diagnosing periprosthetic joint infection

Aim. Low-grade infections cannot be easily distinguished from aseptic complications frequently leading to false negative diagnoses and late onset of anti-bacterial therapy. Therefore, there is a great need to establish biomarkers for early detection of low-grade infections. Method. In this study, we focused on the investigation of anti-α-defensin, anti-C3, anti-C5 and anti-C9 as potential biomarkers for infection in a cohort of hip and knee septic revision cases, taking patient characteristics and comorbidities into account. Here we included 78 patients with septic (35) and aseptic (43) (woman:37, men:42, age 50 – 93 years) revision surgeries of hip and knee. CRP serum levels and leucocyte blood values were evaluated. Patient characteristics, including age, number of prior revision surgeries and comorbidities were recorded. Periprosthetic tissue was stained histologically with Hematoxylin/Eosin and immunohistologically with different antibodies. Results. The CRP values were significantly increased in the septic cohort, but no changes were observed in leucocyte count. Interestingly, we found a strong increase in the terminal complement system component C9 (septic: 0.1% ± 0.2% aseptic: 0.01% ± 0.05%, p= 0.0004) in the septic periprosthetic tissue. The predictive value of α-defensin staining was not statistically significant (septic: 0.5% ± 0.7% aseptic: 0.1% ± 0.6%, p= 0.09). Analyzing the synovial fluid of aseptic and septic patients, the presence of C9 in the septic group (1.8 ± 0.4) was not significantly higher compared to the aseptic (1.9 ± 0.7) group. The next step was to investigate the specificity C9 detection using different joint related diseases such as chondrocalcinosis (CC), rheumatoid arthritis (RA) and metallosis. The median of C9 staining in the CC group (0 ± 0.0001) was significant lower than the infection group. Similar results have been observed in RA (0.0003 ± 0.2) and the metallosis group (0.0002 ± 0.01). Conclusions. We found a strong predictive value of anti-C9 staining for tissue infection, suggesting that C9 deposition could be a novel biomarker for the identification of periprosthetic joint infections using tissue biopsies

The biological reaction in metallosis and pseudotumor generation after metal on metal total hip arthroplasty or corroding metal implants remains unsettled. Clinically, still lethal cases appear with massive bone loss and metal ions are suspected to be responsible for this inflammatory reaction, solid metal wear particles instead are usually not observed in the common literature. The aim of this study was to compare the biological reactions of metal ions and metal wear particles in a murine in vivo model. Metal ions (CoCr), metal particles (CoCr), polyethylene particles (UHMWPE) and phosphate buffered saline (PBS) were injected into the left knee joint of female BALB/c mice. 7 days after injection, the microcirculation was observed using intravital fluorescence microscopy, followed by euthanasia of the animals. After the assessment of the knee diameter, the knees underwent histological evaluations of the synovial layer. Throughout all recorded data, CoCr particles caused higher inflammatory reactions compared to metal ions and UHMWPE particles. The mice treated with the solid particles showed enlarged knee diameters, more intensive leukocyte–endothelial cell interactions and an elevated functional capillary density. Pseudotumor-like tissue formations in the synovial layer of the mice were only seen after the exposition to solid CoCr particles. Even if the focus of several national guidelines concerning metallosis and pseudotumor generation is on metal ions, the present data reveal that solid CoCr particles have the strongest inflammatory activity compared with metal ions and UHMWPE particles in vivo

Introduction. The MHRA guidelines for metal on metal (MOM) suggest cobalt and chromium levels of more than 7ppb as potential for soft tissue reaction. However, in some patients soft tissue reaction is seen even in the presence of normal serum metal ions levels. Methods. A prospective review of all patients who had metal-on-metal hip arthroplasty was done. Patients who had both serum metal ion levels and MARS MRI scan were included in this study. Results. There were 574 patients with 319 females and 255 males. 240 patients had both MARS MRI scan and serum metal ions. Fifty nine (24.5%) patients with normal metal ions had metallosis/pseudo tumour on MRI scans, and 17 (7%) patients with increased metal ions had normal MRI scans. Conclusion. This study confirms that there is poor correlation between serum metal ions and soft tissue reaction. Nearly a quarter of patients with normal serum metal ions had evidence of metallosis on MRI scan. Clinicians should be aware of the potential for soft tissue reaction even in the presence of normal metal ions. Hence, consideration should be given to further imaging where appropriate, to ensure early metallosis is picked up and further complications of pseudo tumour prevented

Introduction. Osteloysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported, as is lack of osteolysis following Ceramic-on-Ceramic (CoC)THA. Early ceramic failures did report some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term use, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. Osteolysis reported after 3rd generation CoC THA often included metallosis due to neck rim impingement. In our department we have revised only 2 hips in over 6000 CoC THAs for osteolysis. Both had evidence of metallosis as well as ceramic wear. The technique used by Radiologists for identifying the nature of lesions on CT is the Hounsfield score which will identify the density of the tissue within the lucent area. It is common for radiologist to have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA which states there is osteolysis? Revision of such implants in elderly patients has a high risk of morbidity and mortality. Objectives. This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Methods. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15 year review with 3rd generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Results. Eleven of the CTscans were reported to show acetabular osteolysis, two reported osteolysis or possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Conclusions. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans

Introduction: As candidates for arthroplasty become younger and life expectancy increases the required working life of a total hip arthroplasty continues to rise. Hip resurfacing offers potential further advantages in young patients as minimal bone resection makes for easier revision, and the design allows for an increased range of movement. The Birmingham Hip Resurfacing (BHR) is the first of the second generation hip resurfacings. Reports are beginning to emerge of unexplained failure, pseudotumour formation, individual cases of metallosis. Joint registry data also demonstrates an unexplained high early failure rate for all designs of hip resurfacing. This paper examines the rate and mode of early failures of the BHR in a multi-centre, multi-surgeon series. Methods: All patients undergoing BHRs in our two centres were recruited prospectively into our arthroplasty follow up programme. Patients have been followed up radiographically and with clinical scores. Results: Mean radiographic and clinical follow up was to 43 months (range 6 – 90 months). Of the 463 BHRs two have died and three are lost to follow up. Thirteen arthroplasties (2.8%) have been revised. Eight for pain, three for fracture, two for dislocation and one for sepsis. Of these nine were found to have macroscopic and histological evidence of metalloisis. Survival analysis at 5 years is 95.8% (CI 94.1 – 96.8%) for revisions and 96.9% (CI 95.5 – 98.3%) for metallosis. Discussion: Histopathological examination demonstrated a range of inflammatory changes including necrosis, inflammation, ALVAL and metal containing macrophages. Not all features were associated with each patient and it is likely that these features form part of the spectrum of metal wear debris disease. The likely rate of metallosis is 3.1% at five years. Risk factors for metallosis in this series are female sex, small femoral component, high abduction angle and obesity. We not advocate use of the BHR in patients with these risk factors

Purpose. Complete wear-out of Polyethylene (PE) liner results in severe metallosis following articulation of the artificial head with the acetabular metal shell. We postulated that an adverse response can be led to surrounding bone tissue and new implant after revision surgery because the amount of PE wear particle is substantial and the metal particles are infiltrated in this catastrophic condition. We evaluated clinical characteristics and the survival rate of revision total hip arthroplasty (THA) performed in patients with severe metallosis following failure of PE liner. Materials and Methods. Between January 1996 and August 2004, severe metallosis following complete wear-out of PE liner were identified during revision THA in 28 hips of 28 patients. One patient had died at 7 days after surgery and 3 patients could not be reached at 5 year follow-up. Twenty-four hips of 24 patients (average age, 47.5 years) were followed for at least 6.5 years (average, 11.3 years; range, 6.5–15.9 years) and were evaluated. The mean time interval between prior surgery and the index revision surgery was 9.6 years (range, 4.0–14.3 years). The indications for revision surgery were osteolysis around well-fixed cup and stem in 22 hips and osteolysis with aseptic loosening of the cup in 2 hips. Bubble sign was observed on preoperative radiograph in 10 hips. Total revision, cup revision, and solitary bearing change were performed in 13, 10, and one hip respectively. A cementless implant was used in 23 hips and acetabular reinforcement ring was used in one. Clinical evaluation was performed using Harris hip scores and Kaplan-Meier survival analysis was performed. Multivariate analysis was performed with age, gender, BMI, bone defect type, existence of bubble sign and type of revision surgery as variables to evaluate the association with osteolysis or loosening. Results. One patient who had died from an unrelated medical condition at 6.5 years had hip that were functioning well at the time of death. Average Harris hip score improved from 64.5 points preoperatively to 81.9 points at the last follow-up. Wear and osteolysis were detected at average 8.9 years (3.1–13.5 years) after revision in 14 hips. Acetabular cup was loosened in 9 hips. Re-revision of cup was performed in 5 hips and re-revision of both cup and stem was done in 2 hips. In another hip, cup removal and artificial neck cutting was performed due to severe bone loss following two times of cup re-revision. With radiographic evidence of osteolysis as the end point, the 15-year survival rate was 35.3% (95% confidence interval [CI], 11.6%–59.0%). With radiographic loosening of any implant as the end point, the 15-year survival rate was 54.0% (95% CI, 27.9%–80.1%). Multivariate analysis revealed no variable that had a significant association with osteolysis or loosening. Conclusion. The survival rate of revision THA in patients with metallosis following a failure of a PE liner was low. Substantial amount of PE wear debris and the infiltration of metallic wear particles in the periprosthetic tissues might lead to progressive bone loss and implant loosening after revision THA

INTRODUCTION. Progressive polyethylene wear is associated with the occurrence of osteolysis, which can lead to component loosening and subsequent revision. Massive wear of the polyethylene liner may result in the penetration of the femoral head through the metal shell. Although metallosis after total hip arthroplasty has been well documented in the literature, extensive metallosis with polyethylene wear-through has been only sparsely described. The purpose of the present study was to assess clinical findings and the results of revision total hip arthroplasty in these cases. METHODS. We evaluated seven hips in five patients who underwent revision total hip arthroplasty because of metallosis with polyethylene wear-through. The average age of the patients at the time of hip revision was 70.1 years. There were granulomatous cysts surrounding the hip joint and osteolysis in the greater trochanter or in the acetabulum. Eroded metal shells with worn-through polyethylene were exchanged. Kerboull-type acetabular reinforcement device were used in five hips and GAP cup in two. Distal interlocking femoral stems were used in four hips and extensively porous-coated stems in two. All cases with osteolysis were in addition treated with bulk or morselized allograft bone. The mean duration of follow-up was 3 years. RESULTS. At the time of final follow-up evaluation, none of the hips showed osteolysis. Stable fixation of femoral and acetabular components was achieved in all cases. Bulk allograft bone was resorbed in two cases, but in all other cases grafted bones were united and improve bone stock. CONCLUSIONS. Metallosis with polyethylene wear-through caused severe synovitis and massive osteolysis. Although debridement of the surrounding metallic stained tissue could not be completely done, the clinical result of revision surgery was favorable

Metal-on-metal (MOM) hip arthroplasty has been associated with a variety of new failure modes that may be unfamiliar to surgeons who traditionally perform metal-on-polyethylene THR. These failure modes include adverse local tissue reaction to metal debris, hypersensitivity to metal debris, accelerated wear/metallosis, pseudotumours, and corrosion. A significant number of patients with metal-on-metal hip arthroplasty may present to surgeons for routine followup, concern over their implant, or frank clinical problems. A common issue with MOM hip arthroplasty that can lead to accelerated wear and failure is implant malposition. Malposition of a hard-on-hard bearing can lead to edge loading and accelerated wear at the articular surfaces, which will lead to elevation in blood metal ion levels and metallosis. Distinct from this failure mode is the possibility of metal hypersensitivity, which is believed to be an immunologically mediated reaction to normal amounts of metal debris. Because a modular MOM THR has multiple junctions and tapers that come into contact with one another, there also is the possibility of non-articular metal debris production and corrosion. This type of corrosion reaction can lead to soft tissue destruction not commonly seen with hip resurfacing. Therefore, it is important for orthopaedic surgeons to be aware of the intricacies of following a metal-on-metal hip arthroplasty and to be able to interpret test results such as metal ion levels and cross-sectional imaging. Furthermore, there is a difference in the incidence of problems depending upon the type of implant: hip resurfacing, small-diameter head metal-on-metal total hip replacement, and large diameter head MOM THR. This presentation will discuss the importance of routine monitoring and followup for patients with MOM THR, as well as the utility of measuring blood metal ion levels. The published risk stratification algorithm from the Hip Society will be reviewed

Objectives: To evaluate the outcome of a cementless, low carbon MOM (metal on metal) THR with a 28mm ball-head (PPF STRATEC-SYNTHES, since 2002 BIOMET) and the concentration of metal ions within the intra-articular fluid. Methods: 173 unilateral MOM THR’s performed in 1995 were investigated. Average follow up time was 12 yrs (range 9–14yrs). During the study period there were, 11(6.4%) deaths, 2 (1.2%) lost to F.U. and 5 (2.9%) refused follow up x-rays because of lack of symptoms, and a self perceived perception that these were not necessary. 41 effusions in part of this group could be analysed for levels of Co, Cr and Ni. Results: 112 THR’s (64.7%) were completely symptom free and did not show any signs of osteolysis. 7 THR’s had revision surgery, unrelated to metallosis (1 cup loosening, 1 early infection and 5 late infections that could be attributed to a large amount of necrotic tissue within the joint space). 36 hips (20.8%) showed over time, progressive signs of a metallosis. Clinically none or moderate complaints in the groin were reported, and massive effusions of up to 90ml were present. The osteolysis began in the majority of these cases in the periosteal region of the acetabulum and the trochanter. No loosening of the implants was seen. A quarter of these implants had late dislocations. The CRP was up to three times above normal levels. Only 26 patients (15.0%) could be convinced to undergo further surgery (synovectomy, exchange of head and liner and bone grafting as required). Typical histology showed massive necrosis within the joint and a peri-vascular infiltrate of CD-3 pos. activated T-lymphocytes and L26 pos. B-lymphocytes. These findings have been recently published as ALVAL. In the 41 joint effusions, the mean level of Co was 595.6 μg/l (max 4802.2), Cr 481.1 μg/l (max 4602.9) and Ni 3.7 μg/l (max 14.4). The serum ion levels were up to four times the maximal permitted level (Co 3 μg/l, Cr 3 μg/l, Ni 3 μg/l). Conclusion: High levels of toxic metal ions in the joint space over time can lead to a severe allergic reaction and tissue necrosis. The current literature reports, that almost all MOM bearings show slightly elevated serum metal ion levels, and therefore a much higher concentration must be calculated within the joint space. In our experience, because of the serious consequences and unpredictable onset of metallosis, we no longer use MOM articulations

Introduction: The tribiological properties of bearing surfaces are one of the main topics in discussion in the orthopaedic research. Hard-on-hard bearings are one of the ways to reduce wear rates. Modern hard-on-hard bearing low wear rates depend on the correct pairing of bearing surfaces and strict manufacturing tolerances in surface roughness, clearance, and roundness. There have been some concerns in using ceramic bearings, particularly regarding the fracture rate and their subsequent management. Hence, we present here 2 similar cases that highlight the catastrophic failure of metal head when used subsequently to treat the complication of ceramic fractures in Total Hip Arthroplasty (THA). Case Details: Two patients underwent primary THA at different centres with ceramic-on-ceramic bearing. After an initial asymptomatic period of 2 years, ceramic fracture occurred in both the cases, which were subsequently replaced by metal-on-polyethylene bearings by the primary surgeons. One year after the revision of bearings, both the patients developed severe pain and discomfort, which on further investigation revealed massive metallosis, wear of the metal head and aseptic loosening of the acetabular components with cavitation in acetabulum. Both the patients underwent revision THA under the senior author at our tertiary centre-Wrightington Hospital. Intraoperatively near total erosion of the metal head was noted with more than one litre of black, dense material collection in and around the hip joint revealing extensive metallosis. The acetabular cup was grossly loose and significant loss of bone stock was noted due to metallosis. Single stage revision surgery was performed with impaction bone grafting for deficient acetabulum and cemented components were used. At one-year follow-up none of the cases have shown any further wear or complications. Conclusion: One of the main objectives of successful THA is to improve implant longevity. To achieve this understanding the mechanisms of wear between the interacting surfaces is extremely important. The use of ceramic head is good, but there is always a risk of fracture. We do not recommend using metal heads in cases with prior ceramic fractures, as the wear of metal is most likely to occur as it is an ongoing process due to the residual ceramic debris. Hence in these difficult scenarios we recommend usage of ceramic-on-polyethylene as a safe option to prevent catastrophic erosion of metal head and improve implant longevity

Recent reports about the excellent clinical results of unicondylar knee arthroplasty (UKA; also known as unicompartmental knee arthroplasty), by the minimally invasive approach, have encouraged the adoption of the surgical technique. However, friction between metallic prosthetic components resulting from polyethylene wear may result in the development of metallosis and the use of metal implants has become a huge issue in the worlds recently. Here, we report a case in which a patient underwent UKA and developed metallosis in soft tissues and bone adjacent to an implanted artificial joint three years postoperatively

Metal on Metal coupling in total hip replacement has been widely used since many years. After the rebirth of resurfacing a new trend to use very large diameter metal-metal coupling with standard stem prostheses has been started. New prostheses, old and new problems. We analyze first failures with new large diameter metal on metal coupling. The analysis focused on seven early failures of large diameter metal-metal prostheses (two resurfacing and five cementless prosthesis with XL head) over the first series of 350 cases (100 resurfacing and 250 cementless) in the first year. Synovial fluid aspiration have been performed in all failed patients searching for metal ions and bacterial proliferation. Moreover, prosthetic component positioning was also studied as a possible primum movens of these failures. Some failed patients underwent epicutaneous patch test for skin reaction to metal. One resurface prosthesis failed as a result of an vascular necrosis and conseguent fracture of the femoral neck and revealed a moderate increment in metal ion concentration in blood and synovial fluid obtained at time of revision. One resurface prosthesis failed as a result of an infected metallosis with a huge intraabdominal mass and revealed a huge increment in metal ion concentration in blood, addominal and synovial fluid. This patient underwent a lumbotomy to evacuate the abdominal retroperitoenal mass before prosthesis removal for a two step procedure. Out of the five failures of metal on metal cementless prosthesis with XL head four were the result of aseptic loosening and one was the result of a low grade infection discovered at coltures after revision surgery. Three showed clear metallosis caused by wrong positioning (more than 50° of cup inclination). All of these three presented an articular noise and elevated blood and sinovial fluid metal ion concentration. The fourth patient with aseptic loosening had a good component positioning but demonstrated an epicutanous allergic reaction to Cobalt. Also one of the three patients with metallosis resulted allergic to Cobalt. The blood and sinovial metal ion values were always elevated but particularly high in patients with cup inclination over 50°. Large head metal on metal prostheses demonstrated a higher percentage of early failure in our experience. They are very sensible to positioning. Blood and sinovial metal ion determination helps to promptly diagnose a bad metal on metal prosthetic functioning. A more accurate analysis about the different metals available on the market and their resistance to edge wear should not be delayed any further