Catastrophic Femoral Head-Stem Trunnion Dissociation Secondary to Corrosion

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.

Prosthetic Neck Fracture of a Cementless Titanium Femoral Stem

This case report presents a unique instance of a prosthetic neck fracture in an 81-year-old male with a CERAVER CERAFIT titanium (Ti6Al4V) femoral implant paired with a ceramic-on-ceramic total hip replacement. No fractures of the neck of a titanium femoral stem coated with hydroxy-apatite have been reported in the literature for this type of implant. The patient experienced a sudden, non-traumatic fracture, many years after his primary surgery. The report discusses the clinical presentation, diagnostic findings, known risk factors for femoral neck implant fractures, surgical management, and the outcome.

New Ceramic Heads With Titanium Sleeves on Retained Femoral Components: Results of Over 500 Revision Total Hip Arthroplasties

BACKGROUND

Ceramic heads are frequently combined with titanium sleeves in revision total hip arthroplasties (THAs), ostensibly to protect the ceramic head from existing damage to the retained trunnion. Although widely adopted, data on the performance and safety of this construct are minimal. The purpose of this study was to describe implant survivorships, radiographic results, and clinical outcomes of patients who underwent revision THA with a ceramic head and titanium sleeve on a retained femoral component.

METHODS

We identified 516 revision THAs with femoral component retention (328 acetabular-only revisions and 188 bearing surface exchanges) treated with a new ceramic head and titanium sleeve between 2000 and 2020. Mean age at revision was 64 years, 56% were women, and mean body mass index was 30. The indications for revision THA were adverse local tissue reaction (25%), acetabular loosening (24%), dislocation (17%), infection (5%), and other (29%). Kaplan-Meier survivorships were analyzed, radiographs reviewed, and Harris Hip Scores evaluated. Mean follow-up was 4 years (range, 2 to 10).

RESULTS

There were no reoperations or failures for ceramic head fracture, taper corrosion, or head/sleeve disengagement. The 10-year survivorship free of any re-revision was 85%. Indications for the 57 re-revisions included dislocation (33), infection (13), acetabular component loosening (7), periprosthetic fracture (2), psoas impingement (1), and sciatic nerve irritation (1). The 10-year survivorship free of any reoperation was 82%. There were an additional 14 reoperations. Radiographically, 1.9% had progressive femoral radiolucent lines, and 4.7% had progressive acetabular radiolucent lines. Mean Harris Hip Score was 81 at 2 years.

CONCLUSIONS

New ceramic heads with titanium sleeves in revision THAs with retained femoral components were durable and reliable with no cases of ceramic head fracture or taper complications at mean 4-year follow-up, including those revised for adverse local tissue reaction.

LEVEL OF EVIDENCE

IV.

Ceramic Heads With 12/14 Titanium Sleeves Used on Manufacturer-Non-Compatible Retained Femoral Components Do Not Lead to Implant Failure in Revision Hip Arthroplasty

BACKGROUND

Ceramic femoral heads with titanium sleeves are commonly used in revision total hip arthroplasty (rTHA). Companies advise against combination with a retained femoral component from another manufacturer. However, no data are available. The aim of this study was to evaluate and compare the implant failure and revision rates of ceramic heads with a 12/14 titanium sleeve used on manufacturer-compatible versus noncompatible retained femoral components.

METHODS

A retrospective single-center cohort analysis was performed using a prospectively maintained institutional arthroplasty registry. We identified 439 patients who received a titanium 12/14 ceramic head during rTHA between January 1, 2007, and December 31, 2022. There were 229 manufacturer-compatible and 210 manufacturer-noncompatible retained femoral stems, according to the company's official product compatibility list. Implant failure and rerevision rates were evaluated.

RESULTS

After a median follow-up of 6.6 years (IQR (interquartile range): 4.5 to 9.3), there was no significant difference (P = 0.770) in the rerevision rate between the manufacturer-compatible group (17.0%) and the noncompatible group (18.1%). Revision-free survival after rTHA was 81.2% in the manufacturer-compatible group and 78.9% in the manufacturer-noncompatible group after 15 years (P = 0.653). Most rerevisions occurred in the first year after rTHA, with 29 of 229 (12.7%) in the manufacturer-compatible group and 24 of 210 (11.4%) in the manufacturer-noncompatible group (P = 0.705). We observed only one implant failure in the manufacturer-noncompatible group, but this was not related to a mismatch problem.

CONCLUSIONS

Although legal uncertainties remain, this study showed no increased risk of implant failure or revision rates when a ceramic femoral head, with a 12/14 titanium sleeve, was used on a noncompatible femoral stem from a manufacturer.

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.

Understanding the role of head size and neck length in micromotion generation at the taper junction in total hip arthroplasty

Modular hip implants allow intra-operative adjustments for patient-specific customization and targeted replacement of damaged elements without full implant extraction. However, challenges arise from relative micromotions between components, potentially leading to implant failure due to cytotoxic metal debris. In this study magnitude and directions of micromotions at the taper junction were estimated, aiming to understand the effect of variations in head size and neck length. Starting from a reference configuration adhering to the 12/14 taper standard, six additional implant configurations were generated by varying the head size and/or neck length. A musculoskeletal multibody model of a prothesized lower limb was developed to estimate hip contact force and location during a normal walking task. Following the implant assembly, the multibody-derived loads were imposed as boundary conditions in a finite element analysis to compute the taper junction micromotions as the relative slip between the contacting surfaces. Results highlighted the L-size head as the most critical configuration, indicating a 2.81 μm relative slip at the mid-stance phase. The proposed approach enables the investigation of geometric variations in implants under accurate load conditions, providing valuable insights for designing less risky prostheses and informing clinical decision-making processes.

Can severity of trunnion damage be estimated by visual inspection alone?

Taper corrosion has been widely reported to be problematic for modular total hip arthroplasty implants. A simple and systematic method to evaluate taper damage with sufficient resolution is needed. We introduce a semiquantitative grading system for modular femoral tapers to characterize taper corrosion damage. After examining a unique collection of retrieved cobalt-chromium (CoCr) taper sleeves (n = 465) using the widely-used Goldberg system, we developed an expanded six-point visual grading system intended to characterize the severity, visible material loss, and absence of direct component contact due to corrosion. Female taper sleeve damage was evaluated by three blinded observers using the Goldberg scoring system and the expanded system. A subset (n = 85) was then re-evaluated following destructive cleaning, using both scoring systems. Material loss for this subset was quantified using metrology and correlated with both scoring systems. There was substantial agreement in grading among all three observers with uncleaned (n = 465) and with the subset of cleaned (n = 85) implants. The expanded scoring criteria provided a wider distribution of scores which ultimately correlated well with corrosion material loss. Cleaning changed the average scores marginally using the Goldberg criteria (p = 0.290); however, using the VGS, approximately 40% of the scores for all observers changed, increasing the average score from 4.24 to 4.35 (p = 0.002). There was a strong correlation between measured material loss and new grading scores. The expanded scoring criteria provided a wider distribution of scores which ultimately correlated well with corrosion material loss. This system provides potential advantages for assessing taper damage without requiring specialized imaging devices.

Blood cobalt ion level in patients with different sizes of cobalt/chrome femoral head with the Accolade TMZF stem

BACKGROUND

Corrosion of stem-cobalt/chromium (Co/Cr) head interface and subsequent systemic Co ion complication have been a clinical concern after total hip arthroplasty (THA). The aim of this study is to investigate correlation between type of femoral head and blood Co ion level.

METHODS

One hundred four patients with THA using accolade TMZF and Co/Cr femoral head (32-mm; 55 cases, 36-mm; 20 cases, dual mobility system (DM) with 22.2 or 28-mm inner head; 29 cases) participated in this study, and blood Co ion concentration test was performed in patients a minimum of four years after THA.

RESULTS

DM group was significantly older than 32-mm and 36-mm group (DM: 73.9 ± 4.6, 32-mm: 63.3 ± 8.5, 36-mm: 66.8 ± 10.5). The median (interquartile range) blood Co concentration of each group was 32-mm group 0.26 µg/L (0.69), 36-mm group; 0.21 µg/L (0.30); and DM group 0.21 µg/L (0.13). There was a significant difference of Co concentration between DM and 32-mm group (p = 0.023). Abnormal values of the blood Co concentration (> 1 µg/L) were observed in the 32-mm group; 12 cases (21.8%), 36-mm group; 2 cases (10.0%); and DM group; 0 case (0%) (p = 0.018).

CONCLUSIONS

Co blood concentration differed among the different sizes of Co/Cr femoral head. THA using DM is a safe option with low risk of complication from cobalt ion if it is used for elderly patients.

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.

Intermediate to Long-Term Outcomes and Causes of Aseptic Failure of an At-Risk Femoral Stem

BACKGROUND

The Accolade TMZF is a tapered-wedge cementless metaphyseal-coated femoral stem that was widely utilized from 2002 to 2012. In recent years, there have been reports of early catastrophic failure of this implant. The purposes of the present study were to establish the long-term survival of this stem and to analyze patients who underwent aseptic revision to understand the causes and risk factors for failure.

METHODS

We retrospectively reviewed the records of all patients who had undergone primary total hip arthroplasty with use of an Accolade TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented. Survivorship analysis was performed with use of Kaplan-Meier curves to determine the overall and aseptic survival rates at the time of the latest follow-up. Patient and implant factors commonly associated with aseptic failure were extracted, and a Cox proportional hazards model was used.

RESULTS

A consecutive series of 2,609 patients who had undergone unilateral primary total hip arthroplasty with use of an Accolade TMZF femoral stem were included. The mean time from the primary procedure was 11.3 years (range, 0 days to 19.4 years). The cumulative survival rate was 95.5% ± 0.1% at the time of the latest follow-up. One hundred and seven patients underwent revision surgery, with aseptic loosening of the femoral component being the most common cause of aseptic failure in this cohort (33 of 2,609; 1.3%). Smaller femoral size and larger femoral head offset were independent risk factors for aseptic failure.

CONCLUSIONS

To our knowledge, this is the largest series representing the longest follow-up of this tapered-wedge cementless femoral implant. Despite early concerns, the Accolade TMZF stem had excellent survivorship in this cohort. Trunnionosis as the cause for revision surgery was rare.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Fracture of a triple-polished tapered cemented femoral stem at the Morse taper after metal-on-metal primary total hip arthroplasty

Total hip arthroplasty, one of the most successful orthopaedic procedures, is influenced by several variables. Corrosion at the modular junction is known as trunnionosis. Despite being reported infrequently, corrosion between the femoral head and the Morse taper can result in severe complications. Fracture of the femoral component in primary metal-on-metal (MoM) total hip arthroplasty at the Morse taper is an extremely rare event and can be associated with several risk factors. We report a case of corrosion at the Morse taper in a hybrid primary MoM total hip arthroplasty, resulting in Morse taper fracture with consequent femoral head entrapment inside the acetabular component. We hypothesise that some risk factors, such as age over 60years, active male patients, body mass index above 30kg/m², large femoral heads, high-offset stems, 9/10 Morse taper and MoM-bearing surfaces, are associated with this mode of failure.

Revision Total Hip Arthroplasty Using the Modular Proximal Stem Modified for Asians: Medium-Term Clinical Results and Perioperative Complications

BACKGROUND

This study aimed to examine the medium-term clinical and radiological outcomes of revision THA using the S-ROM-A stem, a modification of the S-ROM stem intended for Asians.

METHODS

Femoral reconstruction using the S-ROM-A stem was performed in 126 hips that underwent revision THA. All patients were followed for perioperative complications. In addition, clinical and radiographic outcomes at a mean of 8 (range 5-14) years postoperatively were evaluated in 96 hips of 86 patients (76%).

RESULTS

The most common perioperative complication was a femoral fracture, occurring in 16 hips (13%), including 11 intraoperative and 5 postoperative fractures. Dislocation occurred in five hips (4.0%), infection in three hips (2.4%), and trunnionosis in two hips (1.6%), including late complications. The total second stem revision was performed in two hips while stem only second revision preserving the bone ingrown sleeve was performed in four hips. With a second revision for aseptic loosening as the endpoint, the 13-year stem survival rate was 100%. Hip function as assessed by the Japanese Orthopedic Association score improved from a mean of 48 points preoperatively to 87 points 8 years postoperatively (P < .05). Radiological evaluation at the final follow-up showed that 95 hips (99%) achieved bone ingrowth fixation and one hip (1%) achieved fibrous stable status.

CONCLUSION

Revision THA using the S-ROM-A stem resulted in good medium-term outcomes. Although modifications of the stem length and shape may be effective in preventing fractures in Asians with relatively small body sizes, attention should be paid to the occurrence of trunnionosis, which may be associated with the decreased taper size.

Catastrophic intraoperative failure of a ceramic femoral head

Approximately 17 years after a primary metal-on-metal total hip arthroplasty, a 59-year-old female developed pain, swelling, and weakness in her right hip accompanied by laboratory findings and imaging suggestive of an adverse local tissue reaction. Acetabular revision was performed to upsize the femoral head and improve hip stability. Upon impaction of the new, non-option ceramic femoral head onto the unsleeved retained stem, the head split into two pieces without fragmentation. The surgery was completed using a cobalt-chromium head, which was impacted without issue onto the stem’s taper. Although BIOLOX delta femoral heads do not require titanium sleeves, we believe that careful consideration should be given to their use in revision total hip arthroplasty with ceramic heads, regardless of the extent of trunnion damage noted intraoperatively.

Horror of three synergistic factors in THA: high mechanical stress, dissimilar metals, low elasticity stem: a case report

Background

A large-diameter femoral head is effective in preventing dislocation after total hip arthroplasty. However, although rare, catastrophic stem tribocorrosion may occur at the head-stem junction.

Case presentation

A 70-year-old woman underwent revision surgery 7.5 years after total hip arthroplasty because of catastrophic stem corrosion with dissociation of the metal head (cobalt/chromium) and stem (TiMo12Zr6Fe2). Abnormal levels of cobalt were found in the intra-articular fluid, capsule, hip muscle, and blood. Revision surgery was performed via the direct anterior approach. The well-fixed femoral stem was explanted, and a cemented stainless stem with stainless head was implanted. Three months after the revision surgery, the cobalt concentration in the blood had decreased to normal.

Conclusions

Stem dissociation in the present case might have been caused by synergistic combination of a 36-mm-diameter femoral head and long neck length offset with high frictional torque, a cobalt-chromium head with a high risk of galvanic corrosion, and a TMZF (TiMo12Zr6Fe2) alloy stem with a low Young’s modulus of elasticity. The combination of these factors must be avoided.

Experimental validation of the abrasive wear stage of the gross taper failure mechanism in total hip arthroplasty

BACKGROUND

Gross taper failure (GTF) is a rare but catastrophic failure mode of the head-stem-taper junction of hip prostheses, facilitated by massive material loss. GTF is a two stage process initiated by corrosion leading to head bottoming out, followed by abrasive wear due to the head rotating on the stem. The purpose of this study was to reproduce the clinical failure patterns and to determine the material loss during simulated gait.

METHODS

Six cobalt-chromium alloy heads (36 mm, 12/14 taper) with three different head lengths (short / medium / extra long) were combined with stem taper replicas made from titanium alloy sized to achieve bottoming out. A hip simulator was used to simulate gait loading after (ISO 14242-1 for 2 million cycles).

RESULTS

Wear patterns from in-vitro testing match the clinical failure patterns. Stem taper wear increased linearly with time (p< 0.001). After two million cycles the material loss of short / medium / extra long heads was (M+-STD) 1168±242 mg / 400±23 mg / 94±12 mg on the stem side and 46±36 mg / 46±24 mg / 70±8 mg on the head side. Stem taper wear decreased with increasing head length (p=0.01), whereas clinical failures are mostly seen for long and extra long heads.

Comparison of Asymptomatic and Symptomatic Adverse Local Tissue Reaction in Patients With Head-Neck Taper Corrosion

BACKGROUND

Diagnosis of adverse local tissue reaction (ALTR) in metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper corrosion is challenging. The purpose of this study is to compare differences between asymptomatic and symptomatic ALTR in an observational cohort, including presentation, metal ion differences, and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) findings.

METHODS

We performed a retrospective review of an observational cohort of 492 MoP THA patients at increased risk of developing ALTR. Ninety-four patients underwent revision arthroplasty for ALTR. Patients were stratified into symptomatic and asymptomatic ALTR groups. Presentation, metal ion levels, and imaging findings were compared.

RESULTS

For patients with confirmed ALTR, 41% were asymptomatic. There was a statistically significant difference in the serum chromium levels between symptomatic and asymptomatic ALTR patients (2.2 μg/L vs 3.1 μg/L, P = .05). There was no statistically significant difference between the serum cobalt levels or MRI findings in these 2 groups. We observed that extracapsular disease associated with ALTR could be misinterpreted as trochanteric bursitis.

CONCLUSION

Almost half of the MoP THA ALTR cases identified were asymptomatic. Cobalt levels could not differentiate between symptomatic and asymptomatic pseudotumor formation. Symptomatic and asymptomatic MoP ALTRs have similar MARS MRI characteristics. Our findings suggest that it is essential to risk stratify patients who could potentially have ALTR based on implant type, symptoms, ion levels, and MARS MRI.

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.

In Vivo Corrosion of Sleeved Ceramic Femoral Heads: A Retrieval Study

BACKGROUND

The purpose of this study was to evaluate a series of retrieved sleeved ceramic femoral heads used in total hip arthroplasty (THA) and determine qualitative and quantitative damage and corrosion patterns.

METHODS

An IRB-approved implant retrieval database was utilized to identify all sleeved ceramic femoral heads collected from 1995 to 2004. There were 16 implants with an average duration of in situ of 70 months (range, 13-241 months). The femoral stem was known in 14 cases and was titanium alloy in each of those cases. None were revised for metal-related complications. Ten implants (63%) were from primary THAs, and 6 (38%) were from revision THAs. Damage and corrosion were qualitatively graded using a modified Goldberg method. A quantitative assessment was performed with a coordinate measurement machine (CMM).

RESULTS

Among the 16 retrieved implants, 1 (6%) demonstrated severe Grade 4 corrosion, 5 (31%) had moderate Grade 3 corrosion, 5 (31%) had mild Grade 2 corrosion, and 5 (31%) had no visible corrosion at the inner sleeve that interfaces with the stem trunnion. The only case of grade 4 corrosion occurred in the only head-sleeve in the study that was not factory assembled and was mated with a titanium molybdenum zirconium ferrous (TMZF) alloy stem. The mean maximum linear corrosion depth at the taper interface, as measured by the CMM, was 7.7 microns (range, 0.9-32.9 microns).

CONCLUSION

This study is the first to quantify corrosion at the titanium interface of sleeved ceramic femoral heads. Potentially clinically significant damage and corrosion patterns were observed in a few failed retrievals; however, the majority of cases demonstrated minimal or no damage.

Bilateral Mechanically-Assisted Crevice Corrosion Resulting in Femoral Stem-Head Dissociation in Metal-on-Polyethylene Total Hip Arthroplasty

There are emerging reports of complications related to corrosion in modular femoral components. We report a unique case describing an 83-year-old man with bilateral mechanically-assisted crevice corrosion in hip replacements performed 10 years previously, by the same surgeon using the same size 3 Accolade TMZF stem and same 44-mm CoCr LFIT V40 head (Stryker Orthopedics, Mahwah NJ). Our patient presented with complete femoral stem-head complex dissociation of his right hip and elevated serum cobalt and chromium levels. He subsequently underwent right hip revision arthroplasty while his contralateral hip is monitored closely as an outpatient. This case helps to define the poorly understood mechanisms and component design factors implicated in this emerging issue. We also hope to provoke discussions about guidelines for monitoring and revising failing metal-on-polyethylene arthroplasty systems.

Impending Trunnion Failure: An Uncommon Radiographic Presentation of Total Hip Arthroplasty Failure

Trunnionosis is emerging as an early mode of failure in conventional metal-on-polyethylene total hip arthroplasty. It is defined as wear or corrosion at the trunnion, the taper at the femoral head-neck interface. Trunnion wear can result in a variety of negative sequelae and, in severe cases, necessitate revision arthroplasty. We describe a 64-year-old man with a metal-on-polyethylene total hip arthroplasty who presented with a sensation of clunking in the hip. Initial imaging and laboratory studies were inconclusive, and the decision was made to monitor. Two years later, trunnion wear was detected on radiographs, presenting as an abnormal alignment of the femoral neck relative to the femoral head. Several case reports and series describe catastrophic total hip arthroplasty failure due to trunnionosis. However, few describe the radiographic signs of wear at the trunnion before gross failure. This early presentation is important to recognize to minimize patient morbidity and aid surgical planning.

Early Disassembly of Femoral Head and Neck Components After Total Hip Arthroplasty Revision

Modular femoral and acetabular components are frequently used in hip arthroplasty. Although the use of modular components offers many advantages, the increased number of components leads to a high risk of disassembly. Disassociation of the femoral head and neck is a rarely reported complication in the literature. This case report depicts a patient with non-traumatic early disassociation of the femoral head and neck components following total hip revision arthroplasty. Femoral head-neck disassembly in early postoperative period may occur due to manufacturing error or insufficient impaction. If sufficient impaction is thought to be achieved, manufacturing errors should be kept in mind as potential underlying reasons for femoral head-neck dissociation.

Bowing-head sign: rare but detectable in pre-catastrophic hip implant failure

Recently, catastrophic failure (i.e., dissociation between the metal femoral head and stem due to stem neck deformation) after total hip arthroplasty (THA) has been reported. Early detection of this complication is very important, because it is accompanied by an increased cobalt concentration in the body, which might influence systemic conditions such as heart failure and immune system diseases. However, early detection of stem neck deformation is considered as difficult. In most cases in the literatures, the diagnosis was made at the time of acute dissociation. We report a case of early detection of stem neck deformation with the 'Bowing-head sign' before acute dissociation. The patient is a 71-year old woman complained of a clicking sensation in the right hip during regular follow-up after THA with a 32-mm cobalt/chromium head with polyethylene insert for osteoarthritis performed 7 years previously. The plain radiograph showed that the angle between the metal femoral head and the axis of the stem neck was not perpendicular ('Bowing-head sign'). Dynamic evaluation under fluoroscopy showed movement of the stem neck in the metal femoral head with hip abduction and adduction. Laboratory data showed abnormal serum cobalt (6.3 μg/L, normal < 1 μg/L) and chromium (3.8 μg/L, normal < 5 μg/L) levels. Considering those radiographic findings, deformation of the stem neck due to trunnionosis was diagnosed, and elective revision surgery was performed without any complications. Plain radiographs after THA should be assessed with attention to this complication, 'Bowing-head sign' must not be overlooked.

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

Three Femoral Stem Designs Without Corrosion: A Review of 2095 Stems

Introduction

Corrosion at the head-neck interface of modular components in total hip arthroplasty (THA) has been reported as a cause of failure of modern total hip replacement implants. While this method of failure has been well described, it remains poorly understood. The purpose of this study is to review the three most commonly used uncemented femoral stems at our institution over the last fifteen years and to correlate any established risk factors with rates of revision, particularly corrosion.

Methods

We reviewed 2095 patients from March 2000 to September 2015 who underwent total hip arthroplasty with one of three uncemented femoral stem designs. All stems were made of a Ti6Al4V alloy with a 12/14 taper design. We included only those stems coupled with a CoCr head and a highly crosslinked polyethylene liner. We evaluated age, gender, body mass index (BMI), femoral head size, head length, neck angle and offset and correlated these to the incidence of all cause revision, as well as revision excluding infection.

Results

There were no recognized corrosion-related revisions identified. There was no association between age, BMI, gender, head length, neck angle and offset to all cause revision or revision with infection excluded (p>0.05). Femoral head size less than 32mm was associated with higher all cause revision rates (OR 4.60 (95% CI 1.8, 11.8)) and when excluding infection as a reason for revision (OR 4.94 (95% CI 1.7, 14.41)).

Conclusion

Over the last fifteen years, we have not identified any cases of corrosion with the three most commonly used femoral stems used at out institution. While we acknowledge that no femoral stem is immune to corrosion, certain femoral stem designs may be uniquely resistant to this mode of failure.

Level of Evidence

III.

Gross Stem Taper Failure with Head Dissociation in a Very Active Patient with an Uncemented Femoral Stem

CASE

We report a case of gross taper failure (GTF) in a very active 81-year-old man 14 years after index operation. The patient presented with acute hip pain and shortening of the left leg. X-rays showed the dissociation of the head. The stem had to be revised because of the massive stem taper damage.

CONCLUSION

This case demonstrates that GTF at the head-stem taper junction following mechanically assisted crevice corrosion is not limited to a specific taper design and material. Other risk factors such as high activity level can lead to this failure pattern also in established stem and taper designs.

Revision of a dual-modular stem in patients with adverse tissue reaction

BACKGROUND

Dual-modular femoral components with exchangeable cobalt-chrome neck segments have had higher than expected failure rates due to corrosion and adverse local tissue reaction (ALTR). Complications, survival rates and early clinical outcomes of revision surgery for the treatment of corrosion and ALTR as a result of these implants are underreported.

METHODS

We identified 44 cases of revision THA for corrosion and ALTR resulting from the same dual modular stem. All revision procedures were performed using a modular tapered fluted titanium stem, ceramic heads and highly cross-linked polyethylene.

RESULTS

Complications included: dislocation, infection, reoperation, and chronic pain. Mean Harris Hip Score was 84 following revision surgery.

CONCLUSIONS

Patients undergoing revision surgery for ALTR related to this prosthesis should be aware of the risk of postoperative dislocation and other complications and the potential long-term risk of some chronic pain.

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.

Fracture of the Neck of a Modern Cementless, Titanium Femoral Stem

Intraprosthetic fracture of a femoral component is a rare but devastating complication after total hip arthroplasty (THA). We present the case of a 68-year-old man who presented with acute hip pain approximately 8 years after a left THA with a modern cementless, titanium femoral component. Radiographs revealed a fracture of the midportion of the neck of the stem, below the level of the trunnion. The patient underwent an isolated 1-component revision THA with a modular exchange. To our knowledge, this is the only reported case of a catastrophic failure fracture of this particular prosthesis.

Gross trunnion failure in metal on polyethylene total hip arthroplasty-a systematic review of literature

BACKGROUND

Multiple cases of dissociation of the head from the neck termed as gross trunnion failure (GTF) in total hip replacement have been described. Very little quantitative data is available for patient and implant factors associated and predisposing to this complication.

STUDY PURPOSE

To systematically review and analyze all studies which have gross trunnion failure in case of metal on polyethylene (MoP) total hip replacement.

METHODS

PubMed database was searched. We also performed a secondary search by pearling bibliography of all full text articles obtained. Predefined inclusion and exclusion criteria were used for abstract screening by two independent observers. A total 46 cases met our inclusion criteria. These were included in the final analysis and data was pooled.

RESULTS

Till date, 46 cases of GTF in MoP THR have been reported. The mean age at time of revision was 70.13 years (range 50 to 89 years). The mean time to revision surgery was 8.24 years (range 4.7 to 14 years). 91.4% cases were male. BMI was ≥ 25 in 38/41 cases and ≥ 30 in 21/41 cases. Pain (95.5%) and difficulty or inability to walk (97.7%) were the most common symptoms. A total of 19/44 cases described varying sounds like click, clunk, and pop before dislocation. Accolade TMZF/TMZF plus was the most common stem used in 34/46 cases. The stem neck angle was 127 degrees in 97% cases (32/33 cases). A positive neck offset of 4 mm or more was used in 91.1% cases (40/44 cases). The head size ≥ 36 mm in approximately 90% cases. The head material was cobalt chromium in all 45 cases, where data was available. Among the intra-operative findings, the most common findings were metallosis (41/44), black or brow coloured synovial fluid (21/44), pseudotumour (19/44), synovial hypertrophy (18/44), damage to the abductor musculature (17/44), proximal femoral osteolysis (5/44 cases), and heterotrophic ossification (2/44 cases). Histopathological analysis was available in 11 cases and was suggestive of fibrous tissue with chronic cellular infiltrate in all cases. The serum cobalt and chromium concentrations were raised above normal in 86.4% (19/22) and 21.7% cases (5/23) respectively.

CONCLUSIONS

Gross trunnion failure may not be as uncommon as was previously thought. A number potential associations and predisposing factors of this complication have been highlighted in this review. But due to small sample size and weak level of evidence, further studies are needed in this field.

The Accolade TMZF stem fulfils the demands of modern stem design: Minimum 5-year survival in a cohort of 937 patients

PURPOSE

Modern hip stem design includes a prosthesis that has a predictable outcome in all total hip arthroplasty (THA) patients, regardless of approach, surgeon or patient characteristics. Introduction without a learning curve and, in cases of problems, the possibility for a simple revision are other prerequisites. The purpose of this study is to evaluate whether the Accolade TMZF stem (Stryker Orthopedics, Mahwah, New Jersey, USA) is suitable to fulfil these demands. We report our mid-term survival of the Accolade TMZF hip stem in all patients from the first implantation at our institute.

METHODS

From the start of using the Accolade TMZF stem (March 2009) until February 2011, 937 THA were performed by 12 surgeons using a posterolateral or anterolateral approach. Survival of the stem was calculated using Kaplan-Meier analysis. Effect of approach, patient age and comorbidity were analysed with a Cox proportional hazards' model. The learning effect was determined by comparing the number of revisions in the surgeons' first 20 THAs with their next 30 THAs and the subsequent THAs.

RESULTS

At 5 years, cumulative stem survival was 97.9% based on revisions for all reasons and 98.8% with aseptic loosening as endpoint. We found no effect of surgical approach, patient age or comorbidity on stem survival. No learning effect was found.

CONCLUSION

The Accolade TMZF stem fulfilled the demands of modern stem design.

Catastrophic femoral head trunnion dissociation: a case series with surface wear analysis

INTRODUCTION

Modular designs enhance accuracy of limb length and offset during total hip arthroplasty. However, such interfaces can be the site of corrosion and implant failure. The purpose of this study was to review 5 cases of catastrophic femoral head trunnion dissociation to better understand clinical and implant related risk factors for this complication.

METHODS

We describe 5 cases of femoral head dissociation following significant trunnion wear. Patient and implant related factors are reviewed. Surface wear patterns were assessed using electron microscopy and wear patterns were described qualitatively.

RESULTS

Commonalties among 5 presented cases include male, age over 65 and increased BMI. All femoral heads were cobalt chromium with a head size of at least 36 mm or greater. 4 out of 5 had high offset. All stems were the same design. Surface wear analysis showed material removed initially on the inferomedial aspect of the trunnion where the femoral head contacted the stem.

CONCLUSIONS

Femoral head dissociation secondary to failure of the trunnion is a rare complication. We show associations with older age, increased BMI and male patients with increased femoral head size and offset. Material is removed initially inferomedially and progresses to fracturing the superior aspect of the trunnion.

Gross trunnion failure after a metal-on-polyethylene total hip arthroplasty leading to dissociation at the femoral head-trunnion interface

Gross trunnion failure (GTF) leading to dissociation at the femoral head-trunnion interface is an uncommon complication after total hip arthroplasty (THA). The incidence of this complication is currently unknown due to the limited number of reported cases but it is significantly more common in the context of a recalled femoral head. This report details the case of a gross trunnion failure and secondary polyethylene failure of a non-recalled metal-on-polyethylene primary THA from a taper type previously reported to be associated with an increased prevalence of mechanically assisted crevice corrosion (MACC). This case describes a 77-year-old man who was 10 years status post right THA presenting with acute-onset right hip pain after trying to rise from a seated position. Radiographs showed that the right femoral head was dissociated from the femoral component. At the time of surgical revision, there was extensive dark metallic debris in the hip joint. A revision THA was performed using a modular revision system. Clinicians must be aware that MACC can eventually lead to GTF, which can result in dissociation at the femoral head-trunnion interface in metal-on-polyethylene primary THA. Further research is needed to determine patient and implant factors that make patients susceptible to MACC/GTF so that adequate screening and patient counseling can be performed.

Role of corrosion in taper failure and head disassociation in total hip arthroplasty of a single design

Modular junctions have been associated with corrosion in total hip arthroplasty. In a small number of cases, disassociation of the femoral head from the stem following gross wear of the taper has been reported. The purpose of this study was to investigate the role of corrosion in the development of mechanical changes leading to disassociation. Twenty-one retrieved stems and heads of one design previously reported with head disassociation were identified in an IRB-approved database. Components were scored for corrosion and measured for material loss. Stem alloy hardness was measured. Parametric and non-parametric statistics were performed (α < 0.05). Seven of twenty-one stems demonstrated gross material loss of the stem taper and head disassociation. The maximum linear depth (MLD) of material loss on stem tapers without dissociation and all head bores was 7.63 ± 6.04 and 63.76 ± 60.83 μm, respectively. Hardness of the stem material was statistically distinct, but similar to other stem materials. Results suggest material loss via corrosion at the head bore loosens the taper lock, allowing relative motion leading to abrasive wear of the stem taper. All cases of disassociation occurred at greater than 65 months with a minimum of 50 μm of loss at on the head bore. It may be warranted to survey patients with systems reporting head disassociation; for this system, including recalled heads, risk appears to begin after 6 years in vivo. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2996-3003, 2018.

A case example and literature review of catastrophic wear before catastrophic failure: identification of trunnionosis and metallosis in metal-on-polyethylene hip arthroplasty prior to frank failure or fracture

Though rare, there are documented failures of femoral prosthesis due to corrosion of the head-neck interface in total hip arthroplasty (THA), a phenomenon known as trunnionosis. This wear can result in metallosis, whereby metal debris scatters the surrounding soft tissues. We present on a 58-year-old female who presented with increase in hip and back pain 10 years following right THA using a metal-on-polyethylene construct with a large femoral head (44 mm). Aspiration withdrew metallic fluid, and intraoperative findings showed corrosion of the head-neck taper with surrounding metallosis and pseudocapsule formation. Despite advances in THA design, corrosion and wear between components still exists and may be cause for failure. We present on both the subtle clinical findings and the recommended workup when suspicion is high for trunnionosis, metallosis, or wear, ideally with identification prior to catastrophic failure such as component dislocation or fracture as previously reported.

Retrieval Findings of Recalled Dual-Taper Hips

BACKGROUND

The recent high-profile recalls of several dual-taper hip designs pose questions regarding why those designs perform poorly. We aimed to characterize taper damage in 1 recalled design to understand failure mechanisms to inform surgeons on which patients should be considered at risk of revision and when to revise.

METHODS

High-precision measurement equipment was used to characterize the metal loss from the neck-stem interface of 116 retrieved Rejuvenate femoral stems (Stryker Howmedica Osteonics) revised because of an adverse reaction to metal debris. Head-neck taper surfaces were also investigated, and clinical and laboratory data were examined.

RESULTS

The neck-stem junction of each implant was moderately to severely corroded and showed a characteristic wear pattern on both male and female taper surfaces. The severity of taper damage was positively correlated with time to revision (coefficient, 0.040 [95% confidence interval (CI), 0.028 to 0.051]; p < 0.0001) and with serum cobalt concentration (coefficient, 0.02 [95% CI, 0.01 to 0.02]; p < 0.0001) and serum chromium concentration (coefficient, 0.04 [95% CI, 0.009 to 0.070]; p = 0.0142).

CONCLUSIONS

A forensic examination of the retrieved components that failed secondary to an adverse reaction to metal debris showed, in all cases, visible corrosion. Of the implant and patient factors investigated, we did not identify any predictors of corrosion. The severity of damage was found to increase with time; cobalt was significantly elevated over chromium.

CLINICAL RELEVANCE

Surgeons should scrupulously follow and consider revision for patients with this implant design to avoid extensive tissue excision. Blood metal ion tests may aid in identifying the mechanisms of taper corrosion.

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.

Profound Trunnion Wear Resulting in Femoral Head-Neck Dissociation in Total Hip Arthroplasty

We describe a case of aseptic failure with profound femoral stem trunnion wear and femoral head dissociation nine years after initial primary total hip arthroplasty (THA) with the Stryker Accolade total hip arthroplasty system. Current guidelines for postoperative care and follow-up after THAs as potential intervention points for early detection of prosthetic joint failure are also reviewed.

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.

The onset of fretting at the head-stem connection in hip arthroplasty is affected by head material and trunnion design under simulated corrosion conditions

Mechanically assisted crevice corrosion (MACC) is a mechanism for trunnion damage in total hip arthroplasties (THAs). Retrieval studies have shown reduced MACC-related damage for ceramic heads compared with cobalt-chromium (CoCr) heads. We propose that ceramic heads demonstrate fretting at higher cyclic compressive loads than CoCr heads on titanium alloy trunnions in a simulated corrosion model. A closed electrochemical chamber was used to measure fretting current onset loads for two modern titanium alloy trunnions (Zimmer 12/14 and Stryker V-40) in which trunnion failure has been reported. Ceramic and CoCr alloy 36 + 0 mm heads were impacted on each trunnion and cyclically loaded at 3 Hz with increasing magnitude from 100 to 3,400 N for 540 cycles. Onset load was the cyclic compressive load at which the slope of the average fretting current increased significantly. A CoCr head with V40 trunnion demonstrated the lowest onset load (1,400 N), while the V40 trunnion with a ceramic head showed the highest onset load (2,200 N). Significant differences occurred in average fretting current between head materials for V40 trunnions (p < 0.001) at loads over 2,000 N. CoCr-12/14 and ceramic-12/14 couples demonstrated similar onset loads (2,000 N). All head-trunnion combinations showed cyclical fretting response to loading at 100 N. Head material composition was observed to increase fretting at the taper junction but the effect was taper geometry dependent. Using ceramic heads may reduce the phenomena of trunnion fretting and corrosion but the effect of both trunnion geometry and metallurgy warrants further investigation. Statement of clinical significance: Trunnion corrosion may occur with titanium alloy stems regardless of the head material used. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1630-1636, 2018.

Head size in primary total hip arthroplasty

The use of larger femoral head size in total hip arthroplasty (THA) has increased during the past decade; 32 mm and 36 mm are the most commonly used femoral head sizes, as reported by several arthroplasty registries.The use of large femoral heads seems to be a trade-off between increased stability and decreased THA survivorship.We reviewed the literature, mainly focussing on the past 5 years, identifying benefits and complications associated with the trend of using larger femoral heads in THA.We found that there is no benefit in hip range of movement or hip function when head sizes > 36 mm are used.The risk of revision due to dislocation is lower for 36 mm or larger bearings compared with 28 mm or smaller and probably even with 32 mm.Volumetric wear and frictional torque are increased in bearings bigger than 32 mm compared with 32 mm or smaller in metal-on-cross-linked polyethylene (MoXLPE) THA, but not in ceramic-on-XLPE (CoXLPE).Long-term THA survivorship is improved for 32 mm MoXLPE bearings compared with both larger and smaller ones.We recommend a 32 mm femoral head if MoXLPE bearings are used. In hips operated on with larger bearings the use of ceramic heads on XLPE appears to be safer. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170061.

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.

Bead debonding from a modern cementless total hip femoral component with concomitant taper corrosion

We report a case of bead shedding from a cylindrical extensively porous-coated cementless femoral component with concomitant taper corrosion at the modular head-neck junction of a metal-on-polyethylene total hip prosthesis. The patient presented with chronic thigh pain 4 years after primary total hip arthroplasty, and radiographs revealed significant osteolysis and metallic debris around the femoral stem. Intraoperatively, the patient had a grossly loose femoral component with debonding of sintered beads from the femoral stem, as well as evidence of taper corrosion. We identify a failure of a modern beaded femoral component in conjunction with taper corrosion.

Ceramic Bearings with Titanium Adapter Sleeves Implanted During Revision Hip Arthroplasty Show Minimal Fretting or Corrosion: a Retrieval Analysis

BACKGROUND

The BIOLOX® option system, consisting of a BIOLOX® delta ceramic femoral head with a titanium alloy adapter sleeve, is being increasingly utilized in revision hip arthroplasty. The sleeve protects the ceramic head from fracture and improper motion about the stem trunnion when a damaged trunnion is encountered at revision surgery. Corrosion and fretting due to metal-metal contact at the taper region of hip prosthesis create the potential of causing periprosthetic osteolysis and adverse local tissue reactions.

QUESTIONS/PURPOSES

The objective of this study was to identify the type and extent of damage to retrieved sleeves and ceramic heads to determine their in vivo performance.

METHODS

Twenty-four ceramic heads with titanium alloy sleeves were examined. The articular and taper surfaces for each ceramic head were assessed for metal transfer using a subjective grading system. All surfaces of the 24 titanium sleeves and stem trunnions (only available for 7 of 24 cases) were assessed for corrosion and fretting using an established grading system. Scanning electron microscopy and energy dispersive X-ray analysis were conducted on representative sample of sleeves.

RESULTS

Fretting and corrosion were higher at the inner surface of the taper sleeve than the outer sleeve. Mean fretting scores at the inner taper and outer taper sleeve surfaces were 1.8 and 1.2, respectively. The mean corrosion score at the inner taper surface was 1.8; no corrosion was observed on the outer surface of any taper sleeve. SEM and EDS analyses provided further indications of low levels of damage.

CONCLUSION

Fretting and corrosion were less severe than previously reported for conventional THA metal-metal taper connections, indicating that a ceramic head and titanium sleeve is a safe alternative in revision THA.

Trunnion Failure of the Recalled Low Friction Ion Treatment Cobalt Chromium Alloy Femoral Head

BACKGROUND

Gross trunnion failure (GTF) is a rare complication in total hip arthroplasty (THA) reported across a range of manufacturers. Specific lots of the Stryker low friction ion treatment (LFIT) anatomic cobalt chromium alloy (CoCr) V40 femoral head were recalled in August 2016. In part, the recall was based out of concerns for disassociation of the femoral head from the stem and GTF.

METHODS

We report on 28 patients (30 implants) with either GTF (n = 18) or head-neck taper corrosion (n = 12) of the LFIT CoCr femoral head and the Accolade titanium-molybdenum-zirconium-iron alloy femoral stems. All these cases were associated with adverse local tissue reactions requiring revision of the THA.

RESULTS

In our series, a conservative estimate of the incidence of failure was 4.7% (n = 636 total implanted) at 8.0 ± 1.4 years from the index procedure. Failures were associated with a high-offset 127° femoral stem neck angle and increased neck lengths; 43.3% (13 of 30) of the observed failures included implant sizes outside the voluntary recall (27.8% [5 of 18] of the GTF and 75.0% [8 of 12] of the taper corrosion cases). Serum cobalt and chromium levels were elevated (cobalt: 8.4 ± 7.0 μg/mL; chromium: 3.4 ± 3.3 μ/L; cobalt/chromium ratio: 3.7). The metal artifact reduction sequence magnetic resonance imaging demonstrated large cystic fluid collections typical with adverse local tissue reactions. During revision, a pseudotumor was observed in all cases. Pathology suggested a chronic inflammatory response. Impending GTF could be diagnosed based on aspiration of black synovial fluid and an oblique femoral head as compared with the neck taper on radiographs.

CONCLUSION

In our series of the recalled LFIT CoCr femoral head, the risk of impending GTF or head-neck taper corrosion should be considered as a potential diagnosis in a painful LFIT femoral head and Accolade titanium-molybdenum-zirconium-iron alloy THA with unknown etiology. Almost half of the failures we observed included sizes outside of the voluntary recall.