Adverse reactions to metal debris occur with all types of hip replacement not just metal-on-metal hips: a retrospective observational study of 3340 revisions for adverse reactions to metal debris from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

No Difference in Revision Rates and High Survival Rates in Large-head Metal-on-metal THA Versus Metal-on-polyethylene THA: Long-term Results of a Randomized Controlled Trial

BACKGROUND

Pseudotumor formation is a well-known complication in metal-on-metal (MoM) THA. Pseudotumors combined with elevated serum ion levels and complaints from patients can lead to high revision rates. Long-term (> 10 years) results obtained from randomized trials comparing large-head MoM THA and conventional metal-on-polyethylene (MoP) THA are lacking regarding revision and survival rates, pseudotumor formation, functional outcomes, and serum ion levels.

QUESTIONS/PURPOSES

At 10 years of follow-up, (1) what is the difference in survival and revision rates between large-head (38 to 60 mm) MoM THA and conventional 28-mm MoP THA? (2) What is the difference in pseudotumor formation between large-head MoM THA and MoP THA? (3) Is there a difference in functional outcome between large-head MoM THA and MoP THA? (4) What is the difference in serum ion levels between large-head MoM THA and MoP THA?

METHODS

Between January 2006 and December 2008, 104 patients were randomized to receive either cementless MoM THA (50 patients) or cementless MoP THA (54 patients). In all, 78% (81 of 104) of patients completed the 10-year postoperative follow-up: 36 patients with MoM THA (72%; six patients lost to follow-up) and 45 with MoP THA (83%; four lost to follow-up). In the MoM group, 47% (17) were men, and the patients had a mean ± SD age of 60 ± 5 years. In the MoP group, 38% (17) were men, and the patients had a mean age of 61 ± 5 years. All baseline characteristics were similar between the groups. At 10 years of follow-up, all patient records were screened for revision surgery or complications, and the primary endpoint was survivorship free from revision for any cause at the 10-year follow-up interval, which we analyzed using a Kaplan-Meier survival analysis. All patients had a CT scan to determine the pseudotumor classification, which was reviewed by an independent radiologist. Functional outcome was measured using the patient-reported Oxford Hip Score and Harris Hip Score; the latter was assessed by a blinded nurse practitioner. Finally, serum ion cobalt and chrome concentrations were measured at 10 years postoperatively. Because the a priori sample size calculation for this randomized controlled trial was based on a different endpoint, a post hoc power analysis was performed for this long-term follow-up study, with survival as the primary outcome. It showed that considering the number of included patients, this study would have sufficient power (one-sided testing, alpha 0.05, power 80%) to discern a difference of 20% in the survival rate between the MoP and MoM groups (95% versus 75%).

RESULTS

With the numbers available, there was no difference in survivorship free from revision for any cause between the MoP group and MoM group at 10 years (95% [95% CI 85% to 98%] versus 92% [95% CI 82% to 98%]; p = 0.6). A higher percentage of patients in the MoM group had pseudotumors on CT than those in the MoP group did, but pseudotumors were observed in both groups (56% [20 of 36] in the MoM group versus 22% [10 of 45] in the MoP group, relative risk 1.8 [95% CI 1.2 to 2.6]; p = 0.002). A higher proportion of elevated cobalt and chrome levels was found in the MoM group (19% and 14%, respectively) than in the MoP group (0% for both cobalt and chrome) (cobalt: RR 1.2 [95% CI 1.1 to 1.5]; p = 0.002; chrome: RR 1.2 [95% CI 1.0 to 1.3]; p = 0.01). In 25% of the patients with pseudotumors (5 of 20 patients), there were elevated serum cobalt levels. None of the 23 patients without pseudotumors had elevated cobalt levels (RR 1.3 [95% CI 1.0 to 1.7]; p = 0.01). There was no difference in functional outcome between study groups, nor a difference between patients with a pseudotumor and those without.

CONCLUSION

This study showed that the survival of patients with large-head MoM THA was high and comparable to that of those with MoP THA, which contrasts with the high revision rates reported by others. Although some patients with MoP THAs experienced pseudotumors, the risk of a pseudotumor was much greater in MoM hips, and serum ion levels were higher in patients who received an MoM THA. For these reasons and unknown future complications, continued surveillance of patients with MoM THAs seems important.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Assessing brain integrity in patients with long-term and well-functioning metal-based hip implants

Production of metal debris from implant wear and corrosion processes is now a well understood occurrence following hip arthroplasty. Evidence has shown that metal ions can enter the bloodstream and travel to distant organs including the brain, and in extreme cases, can induce sensorial and neurological diseases. Our objective was tosimultaneously analyze brain anatomy and physiology in patients with long-term and well-functioning implants. Included were subjects who had received total hip or hip resurfacing arthroplastywith an implantation time of a minimum of 7 years (n = 28) and age- and sex-matched controls (n = 32). Blood samples were obtained to measure ion concentrations of cobalt and chromium, and the Montreal Cognitive Assessment was performed. 3T MRI brain scans were completed with an MPRAGE sequence for ROI segmentation and multiecho gradient echo sequences to generate QSM and R2* maps. Mean QSM and R2* values were recorded for five deep brain and four middle and cortical brain structures on both hemispheres: pallidum, putamen, caudate, amygdala, hippocampus, anterior cingulate, inferior temporal, and cerebellum. No differences in QSM or R2* or cognition scores were found between both groups (p > 0.6654). No correlation was found between susceptibility and blood ion levels for cobalt or chromium in any region of the brain. No correlation was found between blood ion levels and cognition scores. Clinical significance: Results suggest that metal ions released by long-term and well-functioning implants do not affect brain integrity.

Failure Following Revision Total Hip Arthroplasty After Cobalt-Chrome Femoral Heads are Placed on a Retained Femoral Stem

BACKGROUND

Failure due to trunnionosis with adverse local tissue reaction (ALTR) has been reported with cobalt-chrome (CoCr) heads in total hip arthroplasty (THA); however, there are limited data on the use of these heads in the revision setting. The purpose of this study was to analyze the outcomes of patients who underwent revision THA with a retained femoral component and received a CoCr femoral head on a used trunnion.

METHODS

In this retrospective review, we identified all patients who underwent revision THA with a retained femoral component and received a CoCr femoral head between February 2006 and March 2014. Demographic factors, implant details, and postoperative complications, including the need for repeat revisions, were recorded. In total, 107 patients were included (mean age 67 years, 74.0% women). Of the 107 patients, 24 (22.4%) required repeat revisions.

RESULTS

Patients who required repeat revision were younger than those who did not (mean age: 62.9 versus 69, P = .03). The most common indications for repeat revision were instability (8 of 24, 33.3%), ALTR (5 of 24, 20.8%), and infection (4 of 18, 16.7%). Evidence of ALTR or metallosis was identified at the time of reoperation in 10 of the 24 patients who underwent re-revision (41.7%).

CONCLUSIONS

The placement of a new CoCr femoral head on a used trunnion during revision THA with a retained femoral component carries a significant risk of complication (22.4%) and should be avoided when possible.

Quantification of trunnion damage in a series of intact total hip arthroplasty femoral stems previously identified to be at risk of catastrophic failure

BACKGROUND

Corrosion at the head-neck junction of femoral stems is a rare complication of total hip arthroplasty (THA) with manifestations ranging from subclinical wear to failure. Prior studies have identified a single femoral component design with an increased propensity for catastrophic trunnion failure. The purpose of the present study was to quantify trunnion damage of this femoral component retrieved from patients undergoing revision THA for non-trunnionosis indications.

METHODS

24 femoral components from a single manufacturer were identified for study inclusion. Each prosthesis underwent stereomicroscopic inspection. Corrosion and fretting scores were assigned per the Goldberg criteria to quadrants of the trunnion. Material loss was calculated based on cone angles across trunnion quadrants. This was carried out using a coordinate measuring machine that digitised each trunnion surface. Stems were compared to a series of femoral stems with the same trunnion design.

RESULTS

20 of the 24 (83%) trunnions demonstrated corrosion, all 24 trunnions demonstrated fretting. Corrosion scores did not statistically differ with respect to trunnion zone (p = 0.53), while fretting scores were higher in the inferior compared to the superior zones (p < 0.001). There was no significant difference in cone angles assessing material loss between stems (p = 0.25).

CONCLUSIONS

Evidence of trunnion damage was observed in each stem retrieved for non-trunnionosis revision. Fretting occurred more frequently about the inferior quadrants. However, digitised trunnion shapes were similar between compared stems exhibiting no material loss. Therefore, it is possible that previous reports of trunnion failures for this implant are not a systemic issue, and that further investigation is required.

Adverse Metal Reaction in a Case of Metal-on-Polyethylene Hip Arthroplasty

Soft tissue inflammatory responses to metal debris from prostheses, categorised as adverse reactions to metal debris (ARMD), are frequent complications of total hip arthroplasty (THA) and often result in implant failure. Introducing modular implant designs in modern orthopaedics has brought benefits to total hip replacements but has also increased patients' susceptibility to corrosion-related risks. ARMD can develop from various metal articulating surfaces, including ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), metal-on-metal (MoM), and metal-on-polyethylene (MoP) configurations. In this case study, a 68-year-old male who underwent a MoP implant for osteoarthritis of the right hip 16 years ago presented with pain and difficulty walking, exacerbated over the past three months. Clinical examination revealed tenderness around the implant and a limited range of motion. Imaging studies, including X-rays and ultrasound-guided aspiration, coupled with normal serum and urinary cobalt (Co) and chromium (Cr) levels, confirmed the diagnosis of ARMD. Given the severity of symptoms and radiographic findings, surgical intervention was warranted, leading to a two-stage revision with implant augmentation using a Burch-Schneider cage. Three months post operation, the patient experienced significant improvements in pain levels, range of motion (ROM), and hip function. This case underscores the importance of vigilant surveillance for ARMD in patients undergoing non-MoM THA, even years post surgery. Prompt recognition and management of ARMD are crucial to mitigate the risk of long-term complications and optimise patient outcomes. Further research is needed to understand the risk factors and mechanisms underlying ARMD in MoP THA, aiding in developing preventive strategies and refined treatment protocols.

Mild aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)-type reactions also present in patients with failed knee prostheses

Aims

Metal particles detached from metal-on-metal hip prostheses (MoM-THA) have been shown to cause inflammation and destruction of tissues. To further explore this, we investigated the histopathology (aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) score) and metal concentrations of the periprosthetic tissues obtained from patients who underwent revision knee arthroplasty. We also aimed to investigate whether accumulated metal debris was associated with ALVAL-type reactions in the synovium.

Methods

Periprosthetic metal concentrations in the synovia and histopathological samples were analyzed from 230 patients from our institution from October 2016 to December 2019. An ordinal regression model was calculated to investigate the effect of the accumulated metals on the histopathological reaction of the synovia.

Results

Median metal concentrations were as follows: cobalt: 0.69 μg/g (interquartile range (IQR) 0.10 to 6.10); chromium: 1.1 μg/g (IQR 0.27 to 4.10); and titanium: 1.6 μg/g (IQR 0.90 to 4.07). Moderate ALVAL scores were found in 30% (n = 39) of the revised knees. There were ten patients with an ALVAL score of 6 or more who were revised for suspected periprosthetic joint infection (PJI), aseptic loosening, or osteolysis. R2 varied between 0.269 and 0.369 for the ordinal regression models. The most important variables were model type, indication for revision, and cobalt and chromium in the ordinal regression models.

Conclusion

We found that metal particles released from the knee prosthesis can accumulate in the periprosthetic tissues. Several patients revised for suspected culture-negative PJI had features of an ALVAL reaction, which is a novel finding. Therefore, ALVAL-type reactions can also be found around knee prostheses, but they are mostly mild and less common than those found around metal-on-metal prostheses.

The size of the femoral head does not influence metal ion levels after metal-on-polyethylene total hip arthroplasty: a five-year report from a randomized controlled trial

Aims

In metal-on-polyethylene (MoP) total hip arthroplasty (THA), large metal femoral heads have been used to increase stability and reduce the risk of dislocation. The increased size of the femoral head can, however, lead to increased taper corrosion, with the release of metal ions and adverse reactions. The aim of this study was to investigate the relationship between the size of the femoral head and the levels of metal ions in the blood in these patients.

Methods

A total of 96 patients were enrolled at two centres and randomized to undergo MoP THA using either a 32 mm metal head or a femoral head of between 36 mm and 44 mm in size, being the largest possible to fit the thinnest available polyethylene insert. The levels of metal ions and patient-reported outcome measures (Oxford Hip Score, University of California, Los Angeles Activity Scale) were recorded at two and five years postoperatively.

Results

At five years, the median levels of chromium, cobalt, and titanium were 0.5 μg/l (interquartile range (IQR) 0.50 to 0.62), 0.24 μg/l (IQR 0.18 to 0.30), and 1.16 μg/l (IQR 1.0 to 1.68) for the 32 mm group, and 0.5 μg/l (IQR 0.5 to 0.54), 0.23 μg/l (IQR 0.17 to 0.39), and 1.30 μg/l (IQR 1 to 2.05) for the 36 mm to 44 mm group, with no significant difference between the groups (p = 0.825, p = 1.000, p = 0.558). There were increased levels of metal ions at two years postoperatively in seven patients in the 32 mm group, compared with four in the 36 mm to 44 mm group, and at five years postoperatively in six patients in the 32 mm group, compared with seven in the 36 mm to 44 mm group. There was no significant difference in either the OHS (p = 0.665) or UCLA (p = 0.831) scores between patients with or without an increased level of metal ions.

Conclusion

In patients who underwent MoP THA, we found no differences in the levels of metal ions five years postoperatively between those with a femoral head of 32 mm and those with a femoral head of between 36 mm and 44 mm, and no corrosion-related revisions. As taper corrosion can start after five years, there remains a need for longer-term studies investigating the relationship between the size of the femoral head size and corrosion in patients undergoing MoP THA.

The effect of trunnionosis on the risk of re-revision following femoral head exchange in hip arthroplasty

BACKGROUND

Fretting corrosion at modular junctions contributes to arthroplasty failure. Currently, no evidence-based guidelines are available regarding the acceptable level of trunnion corrosion that can occur in vivo. We aimed to examine the relationship between trunnion corrosion and risk of re-revision to assist surgeons with intraoperative decision making.

METHOD

Grading by 3 independent examiners of revised and re-revised head components was performed using a modified Goldberg corrosion scale. Samples were separated into low-grade (LG) and high-grade (HG) corrosion. Mechanical testing determined the relationship between corrosion severity and pull-off strength at the head-stem junction.

RESULTS

529 retrieved femoral heads were analysed. A positive association was detected between males and HG corrosion (OR 2.07; 95% CI, 1.45-2.94; p < 0.001). No difference between the survivorship of LG and HG heads was detected (p-value = 0.247). In the re-revised sample, the first implant had a time in situ that was on average 7.97 years longer (95% CI, 5.4-10.6) than that of the subsequent re-revised femoral head. Severe corrosion on the first head was associated with a 37.5 (95% CI, 4.00-1944) fold increase of HG on the subsequent head (p < 0.001). Femoral disassembly force had a positive correlation with stem taper corrosion grade (p = 0.001).

CONCLUSIONS

A well-fixed stem with corrosion may remain in situ.

Case report and review: Angiosarcoma with thrombocytopenia after total hip arthroplasty

Total hip arthroplasty (THA) is a common treatment for osteoarthritis and is also performed for other conditions, such as secondary arthritis due to developmental dysplasia of the hip. Various THA types may be complicated by osteolysis and an inflammatory pseudotumor due to an adverse reaction to metal debris. Rarely, THA has been associated with malignant tumors, but their causality remains unclear. In this case report, we describe a female patient with developmental dysplasia of the hip. She had undergone left metal-on-polyethylene THA, acetabular revision of the THA, and left total knee arthroplasty. In addition, she had a history of dyslipidemia and telangiectasia of the eyes, anemia, hiatal hernia, and pleuritis. A THA-associated mass (suspected to be a pseudotumor) had been detected during a previous hospital admission due to pleuritis. She was hospitalized due to swelling in her left lower limb, fatigue, and bruises. A clinical examination revealed anemia, thrombocytopenia, and growth of the suspected pseudotumor. Within 6 weeks, she presented with bleeding of the oral mucosa, hemoptysis, melena, severe thrombocytopenia that did not respond to treatment, elevated D-dimer and C-reactive protein levels, severe pain, increased osteolysis, and fractures around the THA. Infection or malignancy was suspected, but two trocar biopsies suggested an inflammatory pseudotumor. Since her anemia and thrombocytopenia were considered to have been caused by an inflammatory process within the suspected pseudotumor, her suspected pseudotumor and all THA components were surgically removed. However, she developed severe alveolar hemorrhaging and hypoxia and died 2 weeks after her surgery. Histopathological analysis of her surgical and autopsy samples revealed highly malignant angiosarcoma. Although individual cases of malignancies associated with THA have been reported, the literature lacks a clear association between THA and increased cancer risk. Most pseudotumors are non-malignant. The patient's case presented in this report exemplifies the challenges to the differential diagnosis of a THA-associated pseudotumor and rare angiosarcoma. Atypically rapid tumor growth, severe osteolysis, and deterioration in the general wellbeing suggest a malignant disease.

Targeting of Periprosthetic Muscles for the Ultrasonographic Screening of Hip Abnormalities in Hip Resurfacing Arthroplasty Patients

BACKGROUND

Hip resurfacing arthroplasty (HRA) patients require subsequent annual screening for postoperative complications. Ultrasonography may be useful for this purpose but lacks a screening protocol for hips. The purpose of this study was to evaluate the accuracy of ultrasonography for detecting postoperative complications in HRA patients using a screening protocol that specifically targets periprosthetic muscles.

METHODS

We enrolled 45 hips from 40 HRA patients with a mean follow-up period of 8.2 years. MRI and ultrasonography scans were simultaneously conducted at follow-up. The ultrasonography assessments were conducted on the anterior part of the hip that targets iliopsoas, sartorius, rectus femoris, lateral with anterior superior and inferior iliac spine (ASIS and AIIS) as bony landmarks, and the lateral and posterior parts that target fascia tensor, short rotators, and gluteus minimus, medius, and maximus with greater trochanter and ischial tuberosity as bony landmarks. The accuracy of diagnosing postoperative abnormalities and the visibility of periprosthetic muscles were compared between these two modalities.

RESULTS

Both MRI and ultrasonography detected an abnormal region in eight cases comprising two infections, two pseudotumors, and four patients with greater trochanteric bursitis. Among these cases, four hips required implant removal. The increase in anterior space, measured as the distance between the iliopsoas and resurfacing head, was a good indicator for the abnormal mass in these four HRA cases. In the assessment of periprosthetic muscles, MRI showed a much lower visibility than ultrasonography in the iliopsoas (6.7% vs. 100%), gluteus minimus (6.7% vs. 88.9%), and short rotators (8.8% vs. 71.4%) due to implant halation.

CONCLUSIONS

By targeting periprosthetic muscles, ultrasonography can detect postoperative complications as effectively as MRI assessments in HRA patients. Ultrasonography has superior visibility in the periprosthetic muscles of HRA patients, indicating its utility for the screening of small legions in these cases which may not be visible by MRI.

Analysis of New Orthopaedic Technologies in Large Database Research

Improvements in orthopaedic surgery go hand in hand with technological advances. The present article outlines the historical and current uses of large databases and registries for the evaluation of new orthopaedic technologies, providing insights for future utilization, with robotic-assisted surgery as the example technology.

Imaging of total hip arthroplasty: Part I – Implant design, imaging techniques, and imaging of component wear and fracture

Despite being one of the most reliable procedures in orthopedic surgery, complications can occur after total hip arthroplasty, and radiology plays an essential role in their evaluation. This article will review the various types of hip arthroplasty and their normal appearances on imaging, followed by mechanisms and imaging appearances of component wear and fracture.

A Rare Case of Adverse Reaction to Metal Debris in a Ceramic-on-Ceramic Total Hip Replacement

Adverse Reaction to Metal Debris (ARMD) is one of the most frequent complications after Total Hip Replacement (THR) and often a cause of surgical revision. This is true especially for implants with Metal-on-Metal (MoM) and Large Diameter Heads (LDHs), which are frequently used to improve stability and reduce the risk of dislocation. However, ARMD is not exclusive to MoM replacement, as it can also occur in other implants such Ceramic-on-Ceramic (CoC), Metal-on-Polyethylene (MoP), and Ceramic-on-Polyethylene (CoP). In these non-MoM implants, ARMD is not caused by the tribo-corrosion between bearing surfaces but, rather, by the fretting at the interface between neck and stem of dissimilar metals. A case of a severe ARMD that happened to a 73-year-old female patient with CoC bearing THR at the right hip is presented in this case report. In this case, the ARMD was misdiagnosed for over a year, resulting in the development of a massive pseudotumor. The treatment of choice was a two-stage revision with the implant of a hip megaprosthesis. After more than 2 years of follow-up, complete recovery of hip Range of Motion (ROM) and normalization of chromium and cobalt levels in blood and urine were achieved. Despite the relatively short follow-up period, this can be considered a successful treatment of a major and misdiagnosed ARMD in a non-MoM hip replacement.

The incidence of adverse local tissue reaction due to head taper corrosion after total hip arthroplasty using V40 taper and 36 mm CoCr head

AIMS

Head-taper corrosion is a cause of failure in total hip arthroplasty (THA). Recent reports have described an increasing number of V40 taper failures with adverse local tissue reaction (ALTR). However, the real incidence of V40 taper damage and its cause remain unknown. The aim of this study was to evaluate the long-term incidence of ALTR in a consecutive series of THAs using a V40 taper and identify potentially related factors.

METHODS

Between January 2006 and June 2007, a total of 121 patients underwent THA using either an uncemented (Accolade I, made of Ti₁₂Mo₆Zr₂Fe; Stryker, USA) or a cemented (ABG II, made of cobalt-chrome-molybdenum (CoCrMo); Stryker) femoral component, both with a V40 taper (Stryker). Uncemented acetabular components (Trident; Stryker) with crosslinked polyethylene liners and CoCr femoral heads of 36 mm diameter were used in all patients. At a mean folllow-up of 10.8 years (SD 1.1), 94 patients (79%) were eligible for follow-up (six patients had already undergone a revision, 15 had died, and six were lost to follow-up). A total of 85 THAs in 80 patients (mean age 61 years (24 to 75); 47 (56%) were female) underwent clinical and radiological evaluation, including the measurement of whole blood levels of cobalt and chrome. Metal artifact reduction sequence MRI scans of the hip were performed in 71 patients.

RESULTS

A total of 20 ALTRs were identified on MRI, with an incidence of 26%. Patients with ALTR had significantly higher median Co levels compared with those without ALTR (2.96 μg/l (interquartile range (IQR) 1.35 to 4.98) vs 1.44 μg/l (IQR 0.79 to 2.5); p = 0.019). Radiological evidence of osteolysis was also significantly associated with ALTR (p = 0.014). Median Cr levels were not significantly higher in those with ALTR compared with those without one (0.97 μg/l (IQR 0.72 to 1.9) v 0.67 μg/l (IQR 0.5 to 1.19; p = 0.080). BMI, sex, age, type of femoral component, head length, the inclination of the acetabular component, and heterotopic ossification formation showed no significant relationship with ALTR.

CONCLUSION

Due to the high incidence of local ALTR in our cohort after more than ten years postoperatively, we recommend regular follow-up investigation even in asymptomatic patients with V40 taper and metal heads. As cobalt levels correlate with ALTR occurrence, routine metal ion screening and consecutive MRI investigation upon elevation could be discussed. Cite this article: Bone Joint J 2022;104-B(7):852-858.

Gross Trunnion Failure of a Type 1 Taper After Metal-on-Polyethylene Total Hip Arthroplasty: A Report of 2 Cases

CASE

We describe 2 cases of gross trunnion failure (GTF) in males with Centers for Disease Control and Prevention Class 3 obesity 10 years after metal-on-polyethylene total hip arthroplasty (THA) with a titanium-alloy femoral stem and Type 1 taper. One patient received a large diameter cobalt-chromium femoral head, whereas the other received a smaller diameter head, both with high-offset femoral stems.

CONCLUSION

This is the first report of GTF involving the Echo Bi-Metric femoral stem after metal-on-polyethylene THA, and surgeons should consider the potential complication of GTF when using this specific femoral stem with metal heads in obese male patients.

Uncemented versus cemented arthroplasty after metal-on-metal total hip replacement in patients with femoral neck fractures: a retrospective study

OBJECTIVE

To compare the clinical outcomes of primary metal-on-metal total hip replacement (MoM-TR) converted to uncemented total hip replacement (UTR) or cemented total hip replacement (CTR) in patients with femoral neck fractures (AO/OTA: 31B/C).

METHODS

Patient data of 234 UTR or CTR revisions after primary MoM-TR failure from March 2007 to January 2018 were retrospectively identified. Clinical outcomes, including the Harris hip score (HHS) and key orthopaedic complications, were collected at 3, 6, and 12 months following conversion and every 12 months thereafter.

RESULTS

The mean follow-up was 84.12 (67-100) months for UTR and 84.23 (66-101) months for CTR. At the last follow-up, the HHS was better in the CTR- than UTR-treated patients. Noteworthy dissimilarities were correspondingly detected in the key orthopaedic complication rates (16.1% for CTR vs. 47.4% for UTR). Statistically significant differences in specific orthopaedic complications were also detected in the re-revision rate (10.3% for UTR vs. 2.5% for CTR), prosthesis loosening rate (16.3% for UTR vs. 5.9% for CTR), and periprosthetic fracture rate (12.0% for UTR vs. 4.2% for CTR).

CONCLUSION

In the setting of revision of failed primary MoM-TR, CTR may demonstrate advantages over UTR in improving functional outcomes and reducing key orthopaedic complications.

Adverse reaction to metal debris due to fretting corrosion between the acetabular components of modular dual-mobility constructs in total hip replacement: a systematic review and meta-analysis

Modular dual-mobility (MDM) constructs can be used to reduce dislocation rates after total hip replacement (THR). However, there are concerns about adverse reaction to metal debris (ARMD) as a result of fretting corrosion between the metal liner and shell. This systematic review reports outcomes following THR using MDM components. It was registered with PROSPERO and conducted in line with Cochrane and PRISMA recommendations.Sixteen articles were included overall, with meta-analysis performed on relevant subsets using a random intercept logistic regression model. Estimated median incidence of ARMD requiring revision surgery within study follow-up period was 0.3% (95% CI 0.1 - 1.8%, from 11 cohort studies containing 1312 cases).Serum metal ion levels were mildly raised in 7.9% of cases, and significantly raised in 1.8%, but there was no correlation with worse clinical hip function scores within studies. Dislocation rate was 0.8%. Revision rate was 3.3%.There are mixed reports of wear on the backside of the metal liner from the acetabular shell and screw heads. Both implant design and component malseating are implicated, but currently it is unclear to what extent each factor is responsible.Studies were poor quality with high risk of confounding, especially from trunnion corrosion. We have made recommendations for further work. In the meantime, surgeons should be aware of the potential risk of ARMD when considering using an MDM prosthesis, and, if selecting one, must ensure proper seating of the liner and screws intraoperatively. Cite this article: EFORT Open Rev 2021;6:343-353. DOI: 10.1302/2058-5241.6.200146.

Improving fretting corrosion resistance of CoCrMo alloy with TiSiN and ZrN coatings for orthopedic applications

Total hip replacement is the most effective treatment for late stage osteoarthritis. However, adverse local tissue reactions (ALTRs) have been observed in patients with modular total hip implants. Although the detailed mechanisms of ALTRs are still unknown, fretting corrosion and the associated metal ion release from the CoCrMo femoral head at the modular junction has been reported to be a major factor. The purpose of this study is to increase the fretting corrosion resistance of the CoCrMo alloy and the associated metal ion release by applying hard coatings to the surface. Cathodic arc evaporation technique (arc-PVD) was used to deposit TiSiN and ZrN hard coatings on CoCrMo substrates. The morphology, chemical composition, crystal structures and residual stress of the coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. Hardness, elastic modulus, and adhesion of the coatings were measured by nano-indentation, nano-scratch test, and the Rockwell C test. Fretting corrosion resistance tests of coated and uncoated CoCrMo discs against Ti6Al4V spheres were conducted on a four-station fretting testing machine in simulated body fluid at 1Hz for 1 million cycles. Post-fretting samples were analyzed for morphological changes, volume loss and metal ion release. Our analyses showed better surface finish and lower residual stress for ZrN coating, but higher hardness and better scratch resistance for TiSiN coating. Fretting results demonstrated substantial improvement in fretting corrosion resistance of CoCrMo with both coatings. ZrN and TiSiN decreased fretting volume loss by more than 10 times and 1000 times, respectively. Both coatings showed close to 90% decrease of Co ion release during fretting corrosion tests. Our results suggest that hard coating deposition on CoCrMo alloy can significantly improve its fretting corrosion resistance and could thus potentially alleviate ALTRs in metal hip implants.

Head-Neck Taper Corrosion in Metal-on-Polyethylene Total Hip Arthroplasty: Risk Factors, Clinical Evaluation, and Treatment of Adverse Local Tissue Reactions

Adverse local tissue reaction (ALTR) associated with mechanically assisted crevice corrosion of metal-on-polyethylene (MoP) head-neck modular total hip arthroplasty (THA), similarly observed in the metal-on-metal bearing, is a growing concern in MoP THA patients. Given the complex pathogenesis as well as variable clinical presentation, the diagnosis can be challenging. This article focuses on providing surgeons with an evidence-based update on (1) implant, surgical, and patient risk factors associated with ALTRs; (2) clinical systematic evaluation; and (3) surgical management options for ALTRs in MoP THA patients based on the currently available evidence.

Taper corrosion: a complication of total hip arthroplasty

The focus on taper corrosion in modular hip arthroplasty increased around 2007 as a result of clinical problems with large-head metal-on-metal (MoM) bearings on standard stems. Corrosion problems with bi-modular primary hip stems focused attention on this issue even more.

Factors increasing the risk of taper corrosion were identified in laboratory and retrieval studies: stiffness of the stem neck, taper diameter and design, head diameter, offset, assembly force, head and stem material and loading.

The high variability of the occurrence of corrosion in the clinical application highlights its multi-factorial nature, identifying the implantation procedure and patient-related factors as important additional factors for taper corrosion.

Discontinuing the use of MoM has reduced the revisions due to metal-related pathologies dramatically from 49.7% (MoM > 32 mm), over 9.2% (MoM ⩽ 32 mm) to 0.8% (excluding all MoM).

Further reduction can be achieved by omitting less stiff Ti-alloys and large metal heads (36 mm and above) against polyethylene (PE).

Standardized taper assembly of smaller and ceramic heads will reduce the clinical occurrence of taper corrosion even further. If 36 mm heads are clinically indicated, only ceramic heads should be used.

Taper-related problems will not comprise a major clinical problem anymore if the mentioned factors are respected.

Cite this article: EFORT Open Rev 2020;5:776-784. DOI: 10.1302/2058-5241.5.200013

A systematic review and meta-analysis of survivorship and wear rates of metal and ceramic heads articulating with polyethylene liners in total hip arthroplasty

BACKGROUND

The major joint registries report better survivorship for ceramic on polyethylene over metal on polyethylene bearings in total hip arthroplasty and it is generally accepted that this is due to a lower polyethylene wear rate. We used evidence synthesis to compare survivorship, polyethylene wear rates and metal ion levels for metal-on-polyethylene (MoP) and ceramic-on-polyethylene (CoP) bearings. If wear rates are not dissimilar in vivo this difference in revision rate may have another cause. Modular junctions are a potential source of corrosion and it is postulated that this may result in higher revision rates.

METHODS

We performed a systematic review and meta-analysis comparing the survivorship of MoP and CoP bearings. Odds ratio (95% CI) of revision was calculated. Mean difference (MD) and 95% confidence intervals (CI) were used to compare secondary outcomes of polyethylene wear and metal ion levels. Meta-analysis was performed with a Mantel-Haenszel Random-Effects Model.

RESULTS

6 randomised controlled trials were included. There was no statistically significant difference between MoP and CoP revision rate (OR 1.04; 95% CI, 0.37-2.90, I² = 0%, p = 0.94), linear bearing wear (MD 0.00 mm; 95% CI, -0.05 -0.05, I² = 98%, p = 0.90), nor volumetric bearing wear (MD 33.57 mm³; 95% CI, -215.56-282.70, I² = 98%, p = 0.79). No studies evaluated metal ion levels.

CONCLUSIONS

We found no evidence of a difference in revision rates nor linear and volumetric wear between MoP and CoP bearings in the randomised controlled trials currently available. Our study therefore does not advocate the additional cost associated with the use of ceramic heads in combination with polyethylene bearings in order to minimise revision rates. This contrasts the findings of in vitro studies and the major joint registries.

Sub-toxic levels of Co2+ are anti-inflammatory and protect cartilage from degradation caused by IL-1β

BACKGROUND

Cobalt ions from some orthopaedic implants induce a dose-dependent cytotoxic and pro-inflammatory response. Recent studies show that sub-toxic levels of cobalt influence actin organisation regulating fibroblasts and macrophages behaviour. However little is known about the influence of sub-toxic levels of cobalt on articular cartilage biology and biomechanics. Previously, we have reported that IL-1β signalling in chondrocytes, is regulated by primary cilia and associated intraflagellar transport. Since primary cilia expression is modulated by actin organisation, we set out to test the hypothesis that sub-toxic levels of cobalt regulate cilia expression and IL-1β signalling thereby influencing articular cartilage degradation.

METHODS

Isolated chondrocytes and bovine cartilage explants were subjected to Co²⁺ in the presence and absence of IL-1β. Primary cilia were monitored by confocal immunofluorescence. Nitric oxide and PGE₂ release were used to monitor IL-1β signalling. Degradation of cartilage matrix was assessed by the release of sGAG and the biomechanical properties of the tissue in uniaxial unconfined compression.

FINDINGS

Sub-toxic levels of Co²⁺ (50 μM) blocked IL-1β-induced primary cilia elongation in isolated chondrocytes. This was associated with disruption of pro-inflammatory signalling in both isolated chondrocytes and cartilage explants, and inhibition of cartilage matrix degradation and loss of biomechanical properties.

INTERPRETATION

This study reveals that low levels of cobalt ions are anti-inflammatory, preventing cartilage degradation in response to IL-1β. This mechanism is associated with regulation of primary cilia elongation. These observations provide new insight into the potential beneficial role of cobalt and may lead to novel mechanisms for controlling cartilage inflammation.

Corrosion Concerns? Trends in Metal-on-Polyethylene Total Hip Arthroplasty Revision Rates and Comparisons Against Ceramic-on-Polyethylene up to 10 Years of Follow-Up

BACKGROUND

We compared the revision risk between metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) total hip arthroplasty patients and evaluated temporal changes in short-term revision risks for MOP patients.

METHODS

Primary MOP (n = 9480) and COP (n = 3620) total hip arthroplasties were evaluated from the Medicare data set (October 2005 to December 2015) for revision risk, with up to 10 years of follow-up using multivariate analysis. Temporal change in the short-term revision risk for MOP was evaluated (log-rank and Wilcoxon tests).

RESULTS

Revision incidence was 3.8% for COP and 4.3% for MOP. MOP short-term revision risk did not change over time (P ≥ .844 at 1 year and .627 at 2 years). Dislocation was the most common reason for revision (MOP: 23.5%; COP: 24.8%). Overall adjusted revision risks were not different between MOP and COP up to 10 years of follow-up (P ≥ .181).

CONCLUSIONS

Concerns with corrosion for metal heads do not appear to result in significantly elevated revision risk for MOP at up to 10 years. Corrosion does not appear as a primary reason for revision compared to other mechanisms.

Clinical outcomes and dislocation rates after hip reconstruction using the Bioball system

INTRODUCTION

Instability accounts for 1/3 of revision total hip arthroplasty (rTHA) performed in the UK. Removal of well-fixed femoral stems in rTHA is challenging with a risk of blood loss and iatrogenic damage to the femur. The Bioball universal adaptor (BUA), a modular head neck extension adaptor, provides a mechanism for optimisation of femoral offset, leg length and femoral anteversion. This can avoid the need for femoral stem revision in selected cases.The aim of this study is to present the clinical results and rate of instability following revision with this BUA at a minimum of 2 years follow-up.

PATIENTS AND METHODS

A review of our prospectively collected database was performed. All patients treated with the Bioball device were included. Clinical and radiologic review were performed pre- and post-surgery. Specific enquiry for instability was made. The Oxford Hip Score (OHS), EuroQol (EQ-5D) score and WOMAC scores were calculated pre-and post-operatively. Complications were recorded.

RESULTS

32 rTHA procedures were performed using the Bioball device between 2013 and 2016. 4 patients did not wish to complete post-operative questionnaires. 2 patients (2/28, 7%) complained of recurrent dislocations following their rTHA procedure. 1 patient complained of instability but no dislocation. The median pre-operative EQ-5D was 0.195 (range -0.07-0.85), OHS was 20 (range 5-43) and WOMAC was 29.8 (range 15.5-52.3). The median EQ-5D was 0.85 (range 0.59-1), OHS was 39 (range 21-48) and WOMAC was 91.1 (range 44.5-99.2) at final follow-up. There were significant improvements in the EQ-5D (p = 0.0009), OHS (p = 0.0004) and WOMAC (p = 0.0001).

CONCLUSION

The BUA is associated with significant functional improvement and relatively low dislocation rates in revision THA. It is a viable option for use in the revision setting.

Activation of synovial fibroblasts from patients at revision of their metal-on-metal total hip arthroplasty

Background

The toxicity of released metallic particles generated in metal-on-metal (MoM) total hip arthroplasty (THA) using cobalt chromium (CoCr) has raised concerns regarding their safety amongst both surgeons and the public. Soft tissue changes such as pseudotumours and metallosis have been widely observed following the use of these implants, which release metallic by-products due to both wear and corrosion. Although activated fibroblasts, the dominant cell type in soft tissues, have been linked to many diseases, the role of synovial fibroblasts in the adverse reactions caused by CoCr implants remains unknown. To investigate the influence of implants manufactured from CoCr, the periprosthetic synovial tissues and synovial fibroblasts from patients with failed MoM THA, undergoing a revision operation, were analysed and compared with samples from patients undergoing a primary hip replacement, in order to elucidate histological and cellular changes.

Results

Periprosthetic tissue from patients with MoM implants was characterized by marked fibrotic changes, notably an increase in collagen content from less than 20% to 45–55%, an increase in α-smooth muscle actin positive cells from 4 to 9% as well as immune cells infiltration. Primary cell culture results demonstrated that MoM synovial fibroblasts have a decreased apoptosis rate from 14 to 6% compared to control synovial fibroblasts. In addition, synovial fibroblasts from MoM patients retained higher contractility and increased responsiveness to chemotaxis in matrix contraction. Their mechanical properties at a single cell level increased as observed by a 60% increase in contraction force and higher cell stiffness (3.3 kPa in MoM vs 2.18 kPa in control), as measured by traction force microscopy and atomic force microscopy. Further, fibroblasts from MoM patients promoted immune cell invasion by secreting monocyte chemoattractant protein 1 (MCP-1, CCL2) and induced monocyte differentiation, which could also be associated with excess accumulation of synovial macrophages.

Conclusion

Synovial fibroblasts exposed in vivo to MoM THA implants that release CoCr wear debris displayed dramatic phenotypic alteration and functional changes. These findings unravelled an unexpected effect of the CoCr alloy and demonstrated an important role of synovial fibroblasts in the undesired tissue reactions caused by MoM THAs.

Risk of mature B-cell neoplasms and precursor conditions after joint replacement: A report from the Haematological Malignancy Research Network

Associations between previous joint replacement and B-cell lymphoid malignancies have been reported, but despite numerous reports, associations with the disease subtypes have received little attention. Using a UK-based register of haematological malignancies and a matched general population-based cohort, joint replacements from linked hospital inpatient records were examined. Cases diagnosed 2009-2015 who were aged 50 years or more were included; 8,013 mature B-cell neoplasms comprising myeloma (n = 1,763), diffuse large B-cell lymphoma (DLBCL, n = 1,676), chronic lymphocytic leukaemia (CLL, n = 1,594), marginal zone lymphoma (MZL, n = 957), follicular lymphoma (FL, n = 725) and classical Hodgkin lymphoma (CHL, n = 255), together with monoclonal gammopathy of uncertain significance (MGUS, n = 2,138) and monoclonal B-cell lymphocytosis (MBL, n = 632). Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated relative to 10 age- and sex-matched controls using conditional logistic regression. Having had a joint replacement before diagnosis was associated with myeloma (OR = 1.3, 95% CI 1.1-1.5, p = 0.008) and MGUS (OR = 1.3, 95% CI 1.1-1.5, p < 0.001). Excluding replacements in the year before diagnosis, the MGUS risk remained, elevated where two or more joints were replaced (OR = 1.5, 95% CI 1.2-2.0, p = 0.001), with hip (OR = 1.2, 95% CI 1.0-1.5, p = 0.06) or knee replacements (OR = 1.5, 95% CI 1.2-1.8, p < 0.001). Associations with CHL and two or more replacements (OR = 2.7, 95% CI 1.3-5.6, p = 0.005) or hip replacements (OR = 1.9, 95% CI 1.0-3.4, p = 0.04); and between DLBCL and knee replacements (OR = 1.3, 95% CI 1.0-1.6, p = 0.04) were also observed. Our study reports for the first time a relationship between joint replacements and MGUS; while absolute risks of disease are low and not of major public health concern, these findings warrant further investigation.

F-18 FDG PET brain imaging in symptomatic arthroprosthetic cobaltism

PURPOSE

Imaging studies of cobalt toxicity from cobalt-chromium alloy arthroprosthetics have focused on the local intra-articular and peri-articular presentation from failing joint replacements. Most studies investigating neurological findings have been small case series focused on the clinical findings of memory loss, diminished executive function, tremor, hearing and vision loss, depression, and emotional lability. This study utilizes software-based quantitative analysis of brain metabolism to assess the degree of hypometabolism and areas of susceptibility, determine if a pattern of involvement exists, and measure reversibility of findings after prosthetic revision to cobalt-free appliances.

METHODS

Over 48 months, 247 consecutive patients presenting to an orthopedic clinic with an arthroprosthetic joint containing any cobalt-chromium part were screened with whole blood and urine cobalt levels. A clinically validated inventory of 10 symptoms was obtained. Symptomatic patients with a blood cobalt level above 0.4 mcg/L or urine cobalt greater than 1 mcg/L underwent F-18 FDG PET brain imaging. Analysis was performed with FDA-approved quantitative brain analysis software with the pons as the reference region. Control group was the normal brain atlas within the software.

RESULTS

Of the 247 consecutively screened patients, 123 had blood and urine cobalt levels above the threshold. The 69 scanned patients had statistically significant regional hypometabolism and higher symptoms inventory. Fifty-seven patients were retained in the study. Distribution of hypometabolism was in descending order: temporal, frontal, Broca's areas, anterior cingulate, parietal, posterior cingulate, visual, sensorimotor, thalamic, and lastly caudate. Metal-on-metal (MoM) and metal-on-plastic (MoP) joint replacements produced similar patterns of hypometabolism. Of 15 patients with necessary revision surgery, 8 demonstrated improved metabolism when later re-scanned.

CONCLUSION

All scanned patients had regions of significant hypometabolism. Neurological toxicity from elevated systemic cobalt levels following arthroprosthetic joint replacement has a pattern of regional susceptibility similar to heavy metals and solvents, differing from classical dementias and may occur at blood and urine cobalt levels as low as 0.4 mcg/L and 1 mcg/L, respectively. Presently accepted thresholds for cobalt exposure and monitoring may need revision. Quantitative F-18 FDG PET brain imaging may aid in the decision process for treatment options and timing of possible medical versus surgical intervention.

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.

Taper fretting corrosion with Stryker Anato stem after hip replacement

We report a case of head-neck taper fretting corrosion in a patient who had a total hip replacement with a noncemented Stryker Anato femoral stem and a V40 metal head with a Stryker Tritanium hemispherical socket with a highly cross-linked polyethylene liner (metal on polyethylene) (Stryker, Mahwah, NJ, USA). A 57-year-old man presented with early-onset hip pain after right total hip arthroplasty. Workup was negative for infection. Metal artifact reduction sequence MRI revealed an encapsulated fluid mass. Metal ion cobalt level was elevated at 6 ppb. The patient underwent right revision total hip arthroplasty with excellent results at 1-year follow-up.

Outcome of Re-Revision Surgery for Adverse Local Tissue Reaction in Metal-on-Polyethylene and Metal-on-Metal Total Hip Arthroplasty

BACKGROUND

Adverse local tissue reactions (ALTRs), initially described as a complication of metal-on-metal (MoM) total hip arthroplasty (THA), have also become an important risk factor for implant failure requiring revision surgery in metal-on-polyethylene (MoP) THA due to modular taper corrosion. This study aims to report early complication rates and outcomes as well as potential risk factors for a re-revision.

METHODS

A total of 252 consecutive THA patients who underwent revision for ALTR were reviewed. There were 40 patients (16%) who underwent a second revision: (1) 26 MoP patients with modular taper corrosion and (2) 14 MoM patients. Patient demographics as well as clinical information were analyzed. Binary logistic regression was used to test for associations between re-revision surgery and clinical parameters.

RESULTS

The overall complication rate following initial revision for ALTR was 21%. Sixteen percent of these revision patients required a re-revision. The most common indication for re-revision was dislocation (45%). The complication rate was 35% following a re-revision which included dislocation (36%), infection (36%), fracture (14%), and implant loosening (14%). The rate of patients requiring a third revision was 23% with the most common indications being dislocation (33%) and infection (33%) (P = .032).

CONCLUSION

High rate of early complications (35%) and third revisions (23%) were observed following re-revision of symptomatic ALTR patients with those requiring re-revision associated with extensive intraoperative tissue necrosis. These findings provide clinically useful information that may assist surgeons in clinical decision making and preoperative counseling of both MoM and MoP patients undergoing re-revision surgery for ALTR.

Midterm Outcomes and Frequency of Osteolysis of Total Hip Arthroplasty Using Cementless Modular Stem for Asian Patients

BACKGROUND

Modular stems are useful for total hip arthroplasty (THA) in anatomically difficult dysplasia. Here, we present mean 6.8-year outcomes of cementless primary THA using S-ROM-A (modified modular stem for Asian patients) femoral prosthesis in anatomically difficult cases.

METHODS

Charts of 373 patients (461 hips) undergoing THA (mean age, 58 years) were reviewed for clinical evaluation of modified Merle d'Aubigné-Postel score and Kaplan-Meier survivorship with revision for any reason as the end point. For radiographic analysis, 331 patients (412 hips) followed up for ≥5 years were included. Bearing couples were metal-on-metal (n = 145), metal-on-polyethylene (n = 120), and ceramic-on-polyethylene (n = 147). Radiography and multiplanar computed tomography were performed.

RESULTS

No postoperative dislocation or deep infection occurred. Mean modified Merle d'Aubigné-Postel score improved significantly (10.9 points preoperatively, 16.7 points at last follow-up; P < .001). Cumulative 5- and 10-year stem survival rates were 100% and 84%, respectively (95% confidence interval, 75%-93%). All stems were classified as bone ingrown fixation. Osteolysis occurred in metal-on-metal (42.8%) and metal-on-polyethylene (15.8%) groups. Mean time to osteolysis was ~3 years, with no significant difference between 3 groups (P = .264). In logistic regression, lower cup inclination angle was significantly associated with osteolysis (odds ratio, 0.914; 95% confidence interval, 0.84-0.99; P = .029).

CONCLUSION

S-ROM-A femoral prosthesis achieved excellent midterm fixation, and the modular system was useful in primary THA with severe deformity. Bearing couples are potentially associated with adverse reactions to metal debris. S-ROM-A with ceramic-on-polyethylene bearing couples may be an option for anatomically difficult THA.

Diagnosis and management of implant debris-associated inflammation

Introduction: Total joint replacement is one of the most common, safe, and efficacious operations in all of surgery. However, one major long-standing and unresolved issue is the adverse biological reaction to byproducts of wear from the bearing surfaces and modular articulations. These inflammatory reactions are mediated by the innate and adaptive immune systems.Areas covered: We review the etiology and pathophysiology of implant debris-associated inflammation, the clinical presentation and detailed work-up of these cases, and the principles and outcomes of non-operative and operative management. Furthermore, we suggest future strategies for prevention and novel treatments of implant-related adverse biological reactions.Expert opinion: The generation of byproducts from joint replacements is inevitable, due to repetitive loading of the implants. A clear understanding of the relevant biological principles, clinical presentations, investigative measures and treatments for implant-associated inflammatory reactions and periprosthetic osteolysis will help identify and treat patients with this issue earlier and more effectively. Although progressive implant-associated osteolysis is currently a condition that is treated surgically, with further research, it is hoped that non-operative biological interventions could prolong the lifetime of joint replacements that are otherwise functional and still salvageable.

Metal Ion Release after Hip and Knee Arthroplasty - Causes, Biological Effects and Diagnostics

All metal implants in human bodies corrode which results in metal ions release. This is not necessarily a problem and represents for most patients no hazard. However, if a critical metal ion concentration is exceeded, local or rarely systemic problems can occur. This article summarizes the mechanisms of metal ion release and its clinical consequences. Several situations can result in increased metal ion release: metal-on-metal hip arthroplasties with increased wear, increased micromotion at taper interfaces, direct metal-metal contact (polyethylene wear, impingement), erroneously used metal heads after ceramic head fracture. Possible problems are in most cases located close to the concerned joint. Furthermore, there are reports about toxic damage to several organs. Most of these reports refer to erroneously used metal heads in revisions after a broken ceramic head. There is currently no evidence of carcinogenic or teratogenic effects of implants but data is not sufficient to exclude possible effects. Cobalt and chromium blood levels (favorably in whole blood) should be measured in patients with suspected elevated metal ions. According to current knowledge levels below 2 µg/l seem to be uncritical, levels between 2 and 7 µg/l are considered borderline with unknown biological consequences and levels above 7 µg/l indicate a local problem which should be further diagnosed. Metal ion levels always need to be interpreted together with clinical symptoms and imaging results.

Revision of Failed Metal-on-Metal Total Hip Arthroplasty: Midterm Outcomes of 203 Consecutive Cases

BACKGROUND

Metal-on-metal (MoM) revisions have shown high rates of complications from aseptic loosening, deep infection, and dislocation. The purpose of this study is to report on outcomes and complications of a large consecutive series of patients who were revised for failed MoM total hip arthroplasty (THA).

METHODS

We evaluated 188 patients (203 hips) who underwent revisions of failed MoM THA. Mean age at the revision was 60 years old. Gender was female in 112 hips (55%) and male in 91 hips (45%). Mean interval to failure after primary THA was 4.9 years (range, 0-18 years). The acetabular component was revised in 183 cases (92%). Clinical outcomes assessed included pain score and Harris hip score.

RESULTS

Mean follow-up from revision was 4.2 years. Harris hip score improved from 53.6 pre-revision to 73.5 at most recent follow-up (P < .001). Pain level significantly improved from 17.2 pre-revision to 32.8 post-revision (P < .001). Reoperations occurred in 28 (14%) hips. Re-revision was required in 16 hips (7.9%). The most common reasons for re-revision were aseptic loosening (5), dislocation (3), infection (2), and iliopsoas tendonitis (2). Re-revision was significantly higher in cases of pseudotumor. There was no difference in survival with ultraporous cups. Three hips required re-revision to custom triflange components. All-cause survival was 90.5% at 4.2 years. Metal ion levels significantly declined after revision.

CONCLUSION

Revisions of failed MoM THA showed improvements in clinical outcomes, but present significant surgical challenges and complications especially in cases with soft tissue damage and pseudotumor.

Mechanisms of Adverse Local Tissue Reactions to Hip Implants

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

Hip simulator testing of the taper-trunnion junction and bearing surfaces of contemporary metal-on-cross-linked-polyethylene hip prostheses

Adverse reaction to metal debris released from the taper-trunnion junction of modular metal-on-polyethylene (MoP) total hip replacements (THRs) is an issue of contemporary concern. Therefore, a hip simulator was used to investigate material loss, if any, at both the articulating and taper-trunnion surfaces of five 32-mm metal-on-cross-linked-polyethylene THRs for 5 million cycles (Mc) with a sixth joint serving as a dynamically loaded soak control. Commercially available cobalt-chromium-molybdenum femoral heads articulating against cross-linked polyethylene (XLPE) acetabular liners were mounted on 12/14 titanium (Ti6Al4V) trunnions. Weight loss (mg) was measured gravimetrically and converted into volume loss (mm³ ) for heads, liners, and trunnions at regular intervals. Additionally, posttest volumetric wear measurements of the femoral tapers were obtained using a coordinate measuring machine (CMM). The surface roughness (Sa) of femoral tapers was measured posttest. After 5 Mc, the mean volumetric wear rate for XLPE liners was 2.74 ± 0.74 mm³ /Mc. The CMM measurements confirmed material loss from the femoral taper with the mean volumetric wear rate of 0.045 ± 0.024 mm³ /Mc. The Sa on the worn area of the femoral taper showed a significant increase (p < 0.001) compared with the unworn area. No other long-term hip simulator tests have investigated wear from the taper-trunnion junction of contemporary MoP THRs. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:156-166, 2020.

Comparative Mid-term Follow-up Study of Primary Total Hip Arthroplasty with Metal-on-metal and Metal-on-polyethylene Bearings

OBJECTIVE

To compare mid-term clinical results of total hip arthroplasty (THA) with metal-on-metal (MoM) and metal-on-polyethylene (MoP) bearings and to evaluate the biological safety of the two kinds of prostheses.

METHODS

Thirty-two patients who received a primary THA with an MoM articulation between January 2008 and December 2010 were selected to form the MoM group retrospectively. The MoP group consisted of 32 patients who received a THA with an MoP prosthesis during the same period. Clinical assessments, imaging examinations, laboratory tests, and metal ion concentration detections were conducted on each patient. Another 32 healthy volunteers were recruited as the control group.

RESULTS

Twenty-seven patients in the MoM group and 28 patients in the MoP group completed the follow-up, with a mean follow-up time of 74.6 and 75.9 months, respectively. The mean Harris score at the latest follow-up was 91.5 ± 5.1 in the MoM group versus 88.9 ± 4.0 in the MoP group (P = 0.22). The MoM group showed a better range of motion in flexion, abduction, and external rotation. Co and Cr levels in the MoM group were 2.5-fold and 2.0-fold of these in the MoP group. A mild change of liver function was observed in both groups, while the values of renal function and humoral immunity stayed static. Elevated proportions of Th1 and Th17 cells and decreased proportion of Th2 cells were observed in the MoM group. The occurrence rate of pseudotumors in the MoM and MoP groups was 40.74% ± 9.45% and 14.28% ± 6.61%, respectively (P < 0.05).

CONCLUSION

At the mid-term follow-up, clinical results were satisfied in both groups. MoM prosthesis could result in elevated serum metal ion levels and there is a higher risk of pseudotumor. Long follow-up is needed to evaluate the safety of MoM prostheses.

Evidence-Based Management of Trunnionosis in Metal-on-Polyethylene Total Hip Arthroplasty: A Systematic Review

Multiple recent reports have indicated a rising awareness of trunnionosis-related implant failures, accounting for up to 3% of all total hip arthroplasty revisions. Moreover, aseptic loosening and osteolysis from local release of metal debris can be the presenting manifestations, and thus the true incidence of trunnionosis is thought to be underreported. Furthermore, the relatively unclear and multifactorial pathogenesis and the widely variable clinical presentations pose a diagnostic challenge. A consensus regarding the ideal intervention and its timing is also lacking. Because of the relative paucity of reports regarding the diagnosis and management of trunnionosis, we conducted this evidence-based review to evaluate the (1) incidence, (2) pathogenesis, (3) diagnosis, and (4) treatment of trunnionosis in metal-on-polyethylene total hip arthroplasty. We then propose an algorithm for the diagnostic work-up and management of this condition.

Revision for adverse local tissue reaction following metal-on-polyethylene total hip arthroplasty is associated with a high risk of early major complications

Aims

Fretting and corrosion at the modular head/neck junction, known as trunnionosis, in total hip arthroplasty (THA) is a cause of adverse reaction to metal debris (ARMD). We describe the outcome of revision of metal-on-polyethylene (MoP) THA for ARMD due to trunnionosis with emphasis on the risk of major complications.

Patients and Methods

A total of 36 patients with a MoP THA who underwent revision for ARMD due to trunnionosis were identified. Three were excluded as their revision had been to another metal head. The remaining 33 were revised to a ceramic head with a titanium sleeve. We describe the presentation, revision findings, and risk of complications in these patients.

Results

The patients presented with pain, swelling, stiffness, or instability and an inflammatory mass was confirmed radiologically. Macroscopic material deposition on the trunnion was seen in all patients, associated with ARMD. Following revision, six (18.2%) dislocated, requiring further revision in four. Three (9.1%) developed a deep infection and six (18.2%) had significant persistent pain without an obvious cause. One developed a femoral artery thrombosis after excision of an iliofemoral pseudotumor, requiring a thrombectomy.

Conclusion

The risk of serious complications following revision MoP THA for ARMD associated with trunnionosis is high. In the presence of extensive tissue damage, a constrained liner or dual mobility construct is recommended in these patients. Cite this article: Bone Joint J 2018;100-B:720-4.

Inferior Radiographic and Functional Outcomes With Modular Stem in Metal-on-Metal Total Hip Arthroplasty

BACKGROUND

Data on the association between stem type and metal-on-metal (MoM) total hip arthroplasty (THA) performance are limited. The aim of this study is to investigate the effect of stem type on the prevalence of osteolysis and radiolucency, blood metal ion levels, and functional outcomes in patients with Articular Surface Replacement THA (ASR XL), a type of MoM THA.

METHODS

We analyzed 539 unilateral MoM THAs coupled with Summit (48%), Corail (35%), or S-ROM (17%) hip stems at a mean follow-up of 6.4 years. Fifty-four percent of the patients were male, and the mean age was 60 years. We studied radiographs, patient-reported outcome measures, and ion levels.

RESULTS

Patients with S-ROM hip stems were 3.8 times more likely to have osteolysis (P = .003) and 7.6 times more likely to have radiolucency (P < .001) than those treated with Summit hip stems. In addition, patients treated with S-ROM hip stems scored worse than those with Summit hip stems in 4 of the 5 patient-reported outcome measures: Harris Hip Score, Visual Analog Scale pain, University of California at Los Angeles activity, and EQ-5D index. All these differences were statistically significant and ranged from 5% to 10%, which is clinically significant.

CONCLUSION

Patients with S-ROM hip stems had inferior functional and radiographic results compared to patients with Summit hip stems. Retrieval studies on large diameter head MoM THA and close follow-up of these patients with hip stems are needed to understand the mechanism causing the differences in outcomes between these stem types.

Trunnion corrosion: what surgeons need to know in 2018

AIMS

To present a surgically relevant update of trunnionosis.

MATERIALS AND METHODS

Systematic review performed April 2017.

RESULTS

Trunnionosis accounts for approximately 2% of the revision total hip arthroplasty (THA) burden. Thinner (reduced flexural rigidity) and shorter trunnions (reduced contact area at the taper junction) may contribute to mechanically assisted corrosion, exacerbated by high offset implants. The contribution of large heads and mixed metallurgy is discussed.

CONCLUSION

Identifying causative risk factors is challenging due to the multifactorial nature of this problem. Cite this article: Bone Joint J 2018;100-B(1 Supple A):44-9.

Angiosarcoma around total hip arthroplasty: case series and review of the literature

BACKGROUND

Angiosarcoma (AS) is a rare and malignant tumor which mainly arises in the skin and superficial soft tissue and less frequently in deep soft tissue and bones. Some cases of AS are described in association with vascular and orthopedic devices. Nonetheless, only a few cases of AS around THA are reported in the literature.

MATERIALS AND METHODS

We describe five cases of AS arising around total hip arthroplasty who received surgery at our institution (Istituto Ortopedico Rizzoli, Bologna, Italy), and we report the cases described in literature.

RESULTS

Foreign bodies such as polyethylene were demonstrated to have a carcinogenic role in animals, but reports of similar cases in humans are rare. Nevertheless, osteolysis induced by wear particles of polyethylene is a frequent event and could induce to desist form considering other more rare causes of osteolysis such as AS. This could be the reason why the diagnosis in several cases was significantly delayed. Common features of these cases could be helpful for doing a prompt diagnosis. The initial presentation is suggestive for septic or aseptic loosening with a massive osteolysis around the cup and/or the stem associated with peculiar aspects as bleeding and loss of weight. Frequently, needle biopsy is negative because foreign-body reaction might have "covered" the most relevant condition of epithelioid AS.

CONCLUSIONS

In conclusion in a patient who presents with uncontrollable bleeding, loss of weight and massive osteolysis, AS must be actually considered as possible diagnosis.

Ion release in ceramic bearings for total hip replacement: Results from an in vitro and an in vivo study

INTRODUCTION

Literature on the potential release of trace elements following implantation of Zirconia-platelet toughened alumina (ZPTA) ceramic components is scant. The present study therefore analysed the in vitro and in vivo potential release of ions from ZPTA bearings.

MATERIAL AND METHODS

An in vitro and in vivo study was conducted. The in vitro study compared leaching in bovine serum from two groups: ZPTA ceramic heads and Co-28Cr-6Mo alloy heads, both 28-mm diameter. A third group without implant served as reference group. An in vivo clinical study compared trace elements in the whole blood of patients with 36-mm diameter ZPTA ceramic-on-ceramic articulation after three and 12 months. A cohort of subjects without any prosthesis was used as control group. The release of ions was determined by high resolution-inductively coupled plasma-mass spectrometry.

RESULTS

In the in vitro experiment, significant differences (p ≤ 0.01) in trace element release for chromium, cobalt and molybdenum were found, with increased levels of ion release in the Co-28Cr-6Mo metal group. The very low detection limit for yttrium allowed detection of a small yttrium release from the ZPTA heads, which was not confirmed by the in vivo study. No significant difference between the groups was found for strontium, aluminium, and zirconium. In the in vivo study, no relevant differences in ion levels between the reference group without any implant and the study group were found at the three and 12-month follow-up.

CONCLUSION

This study supports that ZPTA ceramic articulation components are safe in terms of ion release, and may be an excellent alternative to bearings based on Co-28Cr-6Mo alloys.