Ceramic Head Research Articles

The association of bearing surface materials with the risk of revision following primary total hip replacement: A cohort analysis of 1,026,481 hip replacements from the National Joint Registry.

The risk of re-operation, otherwise known as revision, following primary hip replacement depends in part on the prosthesis implant materials used. Current performance evidences are based on a broad categorisation grouping together different materials with potentially varying revision risks. We investigated the revision rate of primary total hip replacement (THR) reported in the National Joint Registry by specific types of bearing surfaces used. We analysed THR procedures across all orthopaedic units in England and Wales. All patients who received a primary THR between 2003 and 2019 in the public and private sectors were included. We investigated the all-cause and indication-specific risks of revision using flexible parametric survival analyses to estimate adjusted hazard ratios (HRs). We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with head and shell/liner combinations. A total of 1,026,481 primary THRs were analysed (Monobloc: n = 378,979 and Modular: n = 647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n = 7,381 and Modular: n = 13,488). For monobloc implants, compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the all-cause risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome (hazard rate at 10 years after surgery: 1.28 95% confidence intervals [1.10, 1.48]) or stainless steel head (1.18 [1.02, 1.36]) and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any postoperative period (1.18 [1.02, 1.36]). For modular implants, compared to patients with a cobalt chrome head and HCLPE liner primary THR, the all-cause risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic (0.79 [0.73, 0.85]) or oxidised zirconium (0.65 [0.55, 0.77]) head and HCLPE liner had a lower risk of revision throughout the entire postoperative period. Similar results were found when investigating the indication-specific risks of revision for both the monobloc and modular acetabular implants. While this large, nonselective analysis is the first to adjust for numerous characteristics collected in the registry, residual confounding cannot be rule out. Prosthesis revision is influenced by the prosthesis materials used in the primary procedure with the lowest risk for implants with delta ceramic or oxidised zirconium head and an HCLPE liner/cup. Further work is required to determine the association of implant bearing materials with the risk of rehospitalisation, re-operation other than revision, mortality, and the cost-effectiveness of these materials.

Talar head replacement for treatment of Müller – Weiss syndrome: three clinical cases

Introduction Müller – Weiss syndrome is a rare condition that is characterized by avascular necrosis of the navicular bone leading to severe foot deformity, pain disturbing activities of daily living. There is no generally accepted treatment for avascular necrosis of the scaphoid, and the available treatments have disadvantages, which necessitates the need for new options.The objective was to present short-term results of three patients with osteonecrosis of the scaphoid and local necrosis of the talar head treated with ceramic talar head prosthesis, plastic surgery, metal osteosynthesis of the scaphoid and related surgical techniques.Material and methods Three patients diagnosed with Müller – Weiss syndrome were treated with ceramic talar head replacement, autologous bone grafting and metal osteosynthesis of the scaphoid bone with accompanying surgical techniques. Severity of pain and the condition of patients were assessed with the VAS and AOFAS AH scores.Results Short-term results showed consolidation at the site of metal osteosynthesis in all patients with no signs of instability of the talus hemiprosthesis. VAS and AOFAS AH scores indicated decrease in the pain and improved condition of the patients.Discussion Hemiarthroplasty of the talar head combined with plastic surgery and restoration of a congruent joint surface of the scaphoid, and associated surgical techniques may become an effective alternative to existing treatments for patients with Müller – Weiss syndrome, with further study.Conclusion The short-term findings showed that hemiarthroplasty was practical for restoration of the talonavicular mobility maintaining stable fixation of the talus.

Dual-Mobility Articulations in Revision Total Hip Arthroplasty: A Comparison with Metal or Ceramic on Highly Cross-Linked Polyethylene and Constrained Articulations.

The increased availability of dual-mobility acetabular constructs (DMCs) provides surgeons with a newer option to increase the effective femoral head size in revision total hip arthroplasty (rTHA). We sought to evaluate risks of re-revision and prosthetic dislocation following rTHA involving a DMC compared with other articulations. A cohort study was conducted using data from a U.S. integrated health-care system's Total Joint Replacement Registry. Adult patients who underwent primary THA and went on to undergo an aseptic rTHA in 2002 to 2022 were identified. Patients who received a DMC, a constrained liner, or a metal or ceramic unipolar femoral head on highly cross-linked polyethylene (XLPE) at the time of rTHA were the treatment groups. Subsequent aseptic re-revision and dislocation were the outcomes of interest. Multivariable Cox proportional-hazards regression was used to evaluate the risks of the outcomes, with adjustment for patient, operative, and surgeon confounders. The analyzed rTHAs comprised 375 with a DMC, 268 with a constrained liner, 995 with a <36-mm head on XLPE, and 2,087 with a ≥36-mm head on XLPE. DMC utilization increased from 1.0% of rTHAs in 2011 to 21.6% in 2022. In adjusted analyses, a higher re-revision risk was observed for the constrained liner (hazard ratio [HR] = 2.43, 95% confidence interval [CI] = 1.29 to 4.59), <36 mm on XLPE (HR = 2.05, 95% CI = 1.13 to 3.75), and ≥36 mm on XLPE (HR = 2.03, 95% CI = 1.19 to 3.48) groups compared with the DMC group. A higher dislocation risk was observed in both XLPE groups (<36 mm: HR = 2.04, 95% CI = 1.33 to 3.14; ≥36 mm: HR = 2.46, 95% CI = 1.69 to 3.57) compared with the DMC group; a nonsignificant trend toward a higher dislocation rate in the group with a constrained liner than in the DMC group was also observed. In a large U.S.-based cohort, rTHAs using DMCs had the lowest re-revision risk and dislocation risk. Both outcomes were significantly lower than those using a unipolar femoral head on XLPE, re-revision risk was significantly lower than using a constrained liner, and dislocation risk trended toward a lower risk than using a constrained liner. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Incidence of Ceramic Component Fractures in Total Hip Arthroplasty Using Contemporary Ceramic-On-Ceramic Bearings: A Retrospective Study Spanning Two Decades From Two Tertiary Referral Hospitals

IntroductionCeramic-on-ceramic (CoC) bearings have been widely used in total hip arthroplasty (THA) due to their excellent wear properties. However, ceramic component fractures remain a concern. This study aimed to report the incidence of third- and fourth-generation ceramic component fracture and identify factors that might influence this complication. MethodsA total of 9,280 hips that underwent THA with third- and fourth-generation CoC bearings at two tertiary institutions between 1997 and 2023 were retrospectively reviewed, and the incidence and associated factors of CoC bearing fracture were determined. We performed a Kaplan–Meier survival analysis to assess implant survivorship. Logistic regression was applied to evaluate the influence of implant size and patient-specific factors on the risk of revision. ResultsOut of the 9,280 THA procedures, there were 33 (0.36%) revisions for CoC bearing fracture. Specifically, revisions for fracture were performed for zero out of 6,654 fourth-generation CoC heads, 26 (0.990%) of 2,626 third-generation CoC heads, two (0.030%) of 6,654 fourth-generation CoC liners, and five (0.190%) of 2,626 third-generation CoC liners. All ceramic head fractures occurred in a 28 mm head. Younger age was related to both ceramic head and liner fracture. ConclusionsTo our knowledge, this is the largest two-center retrospective study on CoC bearing fractures to date. The risk of revision for fracture of CoC bearings is low, as previously reported. Our data were comparable to recent evidence suggesting that the latest generation of ceramic components can significantly decrease the incidence of head fracture but not liner fracture. Factors such as younger age and men may be associated with an increased risk of ceramic component fractures. Level of evidenceIII, therapeutic.

Quarter Century Outcomes of Alumina Ceramic-on-Ceramic Total Hip Arthroplasty

BackgroundAlumina ceramic-on-ceramic (CoC) bearings were widely used in total hip arthroplasty (THA) due to their superior wear resistance and inert properties, making them ideal for young, active patients who require long-lasting implants. This study aimed to synthesize findings from previous reports, providing a comprehensive follow-up of at least 25 years on the clinical and radiologic outcomes, the prevalence of osteolysis, and implant survivorship in patients undergoing primary cementless CoC THA. MethodsWe have previously reported five-to-ten-year outcomes following the implementation of third-generation alumina-on-alumina bearings in a consecutive series of 100 primary cementless THAs. This report updates those results with a minimum follow-up of 25 years. Of the original cohort, 58 patients who had 67 hips were available for the latest follow-up. Clinical assessments were performed using the Harris Hip Score (HHS) and pain questionnaires. Radiographic evaluations were employed to assess implant fixation and osteolysis. ResultsAt the final follow-up, the implant survival rate was an impressive 96.3%, with revision of the implant as the endpoint. The mean HHS improved significantly from preoperative values to 90.1, indicating excellent functional outcomes. The incidence of ceramic-related noise increased over time, with three cases of ceramic head fractures requiring a change of bearings. Notably, the extent of stem notching observed in earlier reports did not show further progression. Radiologically, all implants demonstrated bony ingrowth with no signs of aseptic loosening or major osteolysis. ConclusionThe long-term (minimum 25-year) follow-up of alumina-on-alumina bearings in primary cementless THA demonstrates outstanding implant survivorship, excellent functional outcomes, and minimal adverse effects over twenty-five years. Despite some issues like ceramic-related noise and component fractures, the overall performance of CoC bearings remains highly encouraging, particularly suitable for young, active patients. Surgeons should provide appropriate education to both potential THA candidates and patients who already have THAs with CoC bearings.

Why Are Contemporary Primary Ceramic–on–Highly Crosslinked Polyethylene Total Hip Arthroplasties Failing? An Analysis of Over 5,500 Cases

BackgroundCeramic–on–highly crosslinked polyethylene (HXLPE) has become the most common bearing surface utilized in primary total hip arthroplasty (THA). The purpose of this study was to determine the implant survivorship and clinical outcomes of THAs with ceramic-on-HXLPE in a large single-institutional series. MethodsWe identified 5,536 primary THAs performed from 2007 to 2017 using a ceramic-on-HXLPE bearing through our total joint registry. The mean age was 60 years, 51% were women, and the mean body mass index was 30. A cementless femoral component was used in 98% of cases, and a head size of ≥ 36 was used in 75%. Kaplan-Meier survivorship analyses were completed to assess survivorship free of any revision or reoperation. Clinical outcomes were assessed via Harris Hip Score. The mean follow-up was four years. ResultsThe 5-year survivorship free of any revision was 97%. The most common indications for revision were dislocation (41 hips), periprosthetic joint infection (39 hips), and periprosthetic femur fracture (18 hips). The 5-year survivorship free of any reoperation was 96%. There were an additional 70 reoperations, with the most common indications being wound dehiscence (32 hips), iliopsoas impingement (11 hips), and periprosthetic femur fracture (11 hips). There were only two bearing surface failures: one HXLPE liner fractured and one dissociated. There were no ceramic head fractures or failures. The mean Harris Hip Score increased from 57 to 92 (P < 0.0001). ConclusionsIn over 5,500 THAs completed with modern ceramic-on-HXLPE bearings, failures of the bearing surface were nearly eliminated at midterm follow-up, and overall 5-year survivorship free of revision was excellent. Dislocation, periprosthetic joint infection, and periprosthetic femur fracture were the most common causes of failure. As bearing surfaces have evolved, traditional failure mechanisms such as polyethylene wear, corrosion and metal reactions, and ceramic fractures have become nearly extinct. Level of EvidenceIII (Case-Control Study), Therapeutic.

A RANDOMIZED CONTROLLED TRIAL OF A CONVENTIONAL VERSUS MODULAR DUAL-MOBILITY BEARING: ARE SERUM METAL LEVELS A CONCERN?

The purpose of this randomized controlled trial was to evaluate serum metal levels in patients undergoing total hip arthroplasty (THA) with a conventional compared to a modular dual-mobility bearing.Patients undergoing primary THA for osteoarthritis were randomized to receive either a modular dual-mobility or conventional polyethylene bearing. All patients received the same titanium acetabular and femoral component and a ceramic femoral head. Serum metal levels were drawn pre-operatively then annually for a minimum of two years postoperatively. An a priori power analysis determined that 40 patients (20 per cohort) were needed to identify a clinically relevant difference in serum cobalt of 0.35 ng/ml (ppb) at 90% power.Forty-six patients were randomized to a modular dual-mobility (n=25) or conventional bearing (n=21) with 40 at a minimum follow-up of two years. No differences in serum cobalt (mean 0.14 ppb [range, 0.075–0.29] vs. 0.20 ppb [range, 0.075–0.57], p=0.39) or chromium levels (mean 0.14 ppb [range, 0.05–0.50] vs. 0.12 ppb [range, 0.05–0.35], p=0.65) were identified between the modular dual-mobility and conventional cohorts, respectively.There was no statistically significant difference in serum Co or Cr at two years postoperatively in subjects implanted with a ceramic head and this particular dual mobility bearing in comparison to a ceramic head and a conventional acetabular component. While modest expected elevations in serum Co and Cr were observed in the dual mobility group, in no case did the Co level exceed the laboratory reference range nor the threshold of one part per billion that has been associated with adverse local tissue reactions to mechanically-assisted crevice corrosion.

THE ASSOCIATION OF BEARING SURFACE MATERIALS WITH THE RISK OF REVISION FOLLOWING PRIMARY TOTAL HIP ARTHROPLASTY: A COHORT ANALYSIS OF 1,026,481 HIP ARTHROPLASTIES FROM THE NATIONAL JOINT REGISTRY

We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by types of bearing surfaces used.We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with head and shell/liner combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR).A total of 1,026,481 primary THRs performed between 2003–2019 are included in the primary analysis (Monobloc: n=378,979 and Modular: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488).Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the all-cause risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period.Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the all-cause risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period.The all-cause and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is lower for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup than commonly used alternatives such as cobalt chrome heads and HCLPE liner/cup.

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

BackgroundCeramic 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. MethodsA 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. ResultsAfter 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. ConclusionsAlthough 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.

May the 4th be with you: mixed-methods best-evidence synthesis on 4th-generation alumina-zirconia ceramic bearings in total hip arthroplasty.

To assess utility, benefits, and risks of 4th-generation alumina-zirconia ceramic pairings in elective total hip arthroplasty (THA). A comprehensive mixed-methods best-evidence synthesis using data from systematic reviews, randomized controlled trials (RCTs), prospective and retrospective cohort studies, as well as joint replacement registries, was conducted to estimate overall revision and survival rates, periprosthetic infection, bearing fractures, and noise phenomena with 4th-generation alumina-zirconia ceramic versus other tribological couplings in elective THA. The systematic review part across multiple databases was registered with PROSPERO (CRD42023418076), and individual study data were extracted for statistical re-analysis. Twenty overlapping systematic reviews, 7, 17, and 8 references from RCTs, cohort studies, and joint replacement registries form the basis of this work. According to current best evidence, it is (i) 15-33 times more likely that 4th-generation alumina-zirconia pairings avoid a revision for infection than causing a revision for audible noise, (ii) 38-85 times more likely that 4th-generation alumina-zirconia pairings avoid a revision for infection than causing a revision for ceramic head fractures, and (iii) three to six times more likely that 4th-generation alumina-zirconia pairings avoid a revision for infection than cause a revision for ceramic liner fractures. Fourth-generation alumina-zirconia pairings in THA show a favorable benefit-risk ratio, with rare compound-specific adverse events and complications significantly outbalanced by long-term advantages, such as a markedly lower incidence of revision for infection.

Characterization of Micro-Threaded Stem Taper Surfaces of Cementless Hip Endoprostheses.

We investigated micro-threaded stem taper surface and its impact on premature failures, aseptic loosening, and infection in cementless hip endoprostheses. Our study focused on the fretting, and crevice corrosion of micro-threaded tapers, as well as the characterization of the microstructure and surface properties of two new and three retrieved Zweymüller stem tapers. The retrieved samples were selected and examined based on the head-stem taper interface being the sole source of modularity with a metallic component, specifically between the Ti alloy taper stem and the ceramic head. To determine the surface chemistry and microstructures of both new and retrieved hip endoprostheses stem taper titanium alloy, scanning -electron microscopy (SEM) was employed for morphological and microstructural analyses. Energy dispersive spectroscopy (EDS) was utilized for characterizing chemical element distribution, and electron backscattered diffraction (EBSD) was used for phase analysis. The roughness of the micro-threated stem tapers from different manufacturers was investigated using an optical profilometer, with standard roughness parameters Ra (average surface roughness) and Rz (mean peak to valley height of the roughness profile) being measured. Electrochemical studies revealed no fretting corrosion in retrieved stem tapers with ceramic heads. Consequently, three retrieved tapers and two new ones for comparison underwent potentiodynamic measurements in Hank's solution to determine the corrosion rate of new and retrieved stem taper surfaces. The results showed a low corrosion rate for both new and prematurely failed retrieved samples due to aseptic loosening. However, the corrosion rate was higher in infected and low-grade infected tapers. In conclusion, our study suggests that using ceramic heads reduces taper corrosion and subsequently decreases the incidence of premature failures in total hip arthroplasty.

The Measurement of the Oxidative Index of Polyethylene Obtained during Revision Hip Arthroplasty and Assessment of Its Variability Depending on the Degree of Osteolysis, Implantation Time, as Well as the Size and Material of the Utilized Head.

Background/Objectives: Aseptic loosening is the leading cause of late revision in total hip arthroplasty, primarily due to degenerative oxidation of polyethylene components, leading to wear particle formation and periacetabular osteolysis. This study aimed to analyze the oxidation levels in polyethylene liners and cemented cups retrieved from revision surgeries using Fourier-transform infrared spectroscopy (FTIR) and to explore the correlation between oxidation levels and factors such as head size, head material, fixation method, and implant survival time. Methods: Polyethylene liners and cups were analyzed post-revision surgery to assess oxidation levels, which were then compared to periacetabular bone loss measured by the Paprosky classification. This study evaluated the impact of head size (28 mm vs. 32 mm), head material (ceramic vs. metal), and fixation methods on oxidation. The relationship between the mean oxidation index (OI) and implant survival time was also investigated. Results: There was a significant positive correlation between the mean oxidation index of the polyethylene components and the severity of periacetabular osteolysis according to the Paprosky scale. While the mean OI for samples articulating with ceramic heads was lower than for those with metal heads, and the mean OI for samples with a 32 mm head size was lower than for those with a 28 mm size, these differences were not statistically significant. Furthermore, the fixation method did not affect the oxidation index, and no correlation was found between OI and the survival time of the implants. Conclusions: This study confirms a direct correlation between polyethylene oxidation and periacetabular osteolysis in hip replacements, highlighting the importance of material choice and design in potentially reducing the risk of aseptic loosening. Despite the lack of significant differences in oxidation levels based on head material and size, these factors may still play a role in the long-term outcome of hip arthroplasty, warranting further investigation.

BEARING SURFACE MATERIALS AND THE RISK OF REVISION FOLLOWING PRIMARY TOTAL HIP ARTHROPLASTY: A COHORT ANALYSIS OF 1,026,481 HIP ARTHROPLASTIES FROM THE NATIONAL JOINT REGISTRY

Hip bearing surfaces materials are typically broadly reported in national registry (metal-on-polyethylene, ceramic-on-ceramic etc). We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by detailed types of bearing surfaces used.We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with detailed head and shell/liner bearing material combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR).A total of 1,026,481 primary THRs performed between 2003–2019 were included in the primary analysis (Monobloc cups: n=378,979 and Modular cups: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488).Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the overall risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period.Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the overall risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period.The overall and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is reduced for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup in reference to THRs with a cobalt chrome head and HCLPE liner/cup.

IS IT SAFE TO USE A CERAMIC-ON-POLYETHYLENE BEARING IN REVISIONS FOR CERAMIC FRACTURE?

Ceramic bearing fracture is a rare complication following implantation using modern day ceramic bearing materials. Revision bearing options in such cases is debated, with the choice between ceramic-on-ceramic and ceramic-on-polyethylene bearings. Revision to a hard on soft bearing raises concerns about potential catastrophic wear secondary to a third-body reaction caused by the fractured ceramic particles.Data was collected retrospectively from the NJR, electronic patient records, revision database and picture archiving and communication system. Templating software was used to determine linear wear between first post-operative radiograph and the latest available follow up. Univariate analysis was used to examine patient demographics and the wear rates for revision of ceramic bearing fractures to ceramic on polyethylene components. The intra and inter-rater reliability of wear measurements was calculated.There were twelve patients identified as meeting the inclusion criteria. The average age at revision was 62 years (54–72). There were 6 liner and 6 head fractures revised to delta ceramic heads and cross-linked polyethylene acetabular components. The most frequently used head size was 32mm. At mean follow up of 3.8 years (0.5 6.1 years), median 4.4 years, linear wear rate was calculated at 0.08± 0.06 mm/year. Both intra-rater and inter-rater reliability was excellent with ICC scores of 0.99 at all timepoints.Revision to ceramic on polyethylene (CoP) bearings following ceramic fracture does not cause early catastrophic wear at early follow up. It appears safe to use this hard on soft bearing combination, given that wear rates are comparable to what is expected in a primary hip replacement setting. Longer follow up is required to establish if this trend persists.

Revision rate in metal compared to ceramic humeral head total shoulder arthroplasty and hemiarthroplasty.

Metal and ceramic humeral head bearing surfaces are available choices in anatomical shoulder arthroplasties. Wear studies have shown superior performance of ceramic heads, however comparison of clinical outcomes according to bearing surface in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) is limited. This study aimed to compare the rates of revision and reoperation following metal and ceramic humeral head TSA and HA using data from the National Joint Registry (NJR), which collects data from England, Wales, Northern Ireland, Isle of Man and the States of Guernsey. NJR shoulder arthroplasty records were linked to Hospital Episode Statistics and the National Mortality Register. TSA and HA performed for osteoarthritis (OA) in patients with an intact rotator cuff were included. Metal and ceramic humeral head prostheses were matched within separate TSA and HA groups using propensity scores based on 12 and 11 characteristics, respectively. The primary outcome was time to first revision and the secondary outcome was non-revision reoperation. A total of 4,799 TSAs (3,578 metal, 1,221 ceramic) and 1,363 HAs (1,020 metal, 343 ceramic) were included. The rate of revision was higher for metal compared with ceramic TSA, hazard ratio (HR) 3.31 (95% confidence interval (CI) 1.67 to 6.58). At eight years, prosthesis survival for ceramic TSA was 98.7% (95% CI 97.3 to 99.4) compared with 96.4% (95% CI 95.2 to 97.3) for metal TSA. The majority of revision TSAs were for cuff insufficiency or instability/dislocation. There was no significant difference in the revision rate for ceramic compared with metal head HA (HR 1.33 (95% CI 0.76 to 2.34)). For ceramic HA, eight-year prosthetic survival was 92.8% (95% CI 86.9 to 96.1), compared with 91.6% (95% CI 89.3 to 93.5) for metal HA. The majority of revision HAs were for cuff failure. The rate of all-cause revision was higher following metal compared with ceramic humeral head TSA in patients with OA and an intact rotator cuff. There was no difference in the revision rate for HA according to bearing surface.

AB165. SOH24AB_216. Matter of prosthetic hip-associated cobalt toxicity (PHACT)?—A clinical case report, and systematic review of cases of PHACT in patients with prosthetic hip ceramic head fractures subsequently revised to metal-on-polyethylene implants

AB165. SOH24AB_216. Matter of prosthetic hip-associated cobalt toxicity (PHACT)?—A clinical case report, and systematic review of cases of PHACT in patients with prosthetic hip ceramic head fractures subsequently revised to metal-on-polyethylene implants

Are Metal Ion Levels Elevated After Dual Mobility Acetabular Systems: Minimum Five-Year Analyses.

While dual mobility systems in total hip replacements have demonstrated reduced dislocation and revision occurrences, concerns persist about the potential elevation of metal ions in the bloodstream, leading to negative tissue reactions. Notably, there's a scarcity of research spanning over five years post-surgery that examines cobalt and chromium levels after such implants. This study aimed to delve into these metal ion concentrations after a five-year period, building on previous metal-ion findings. We focused on: (1) cobalt concentrations in blood and urine; (2) chromium concentrations in blood and urine; (3) cobalt variations based on follow-up duration and specific implant metrics (e.g., offset, cup dimension, stem, and neck inclination); and (4) chromium variations based on the same parameters. We tracked 57 individuals who received THA using modular dual mobility systems from January 1, 2011, to December 31, 2016, for an average span of six years (ranging from five to 10 years). At the final check-up, we measured cobalt and chromium levels in serum, plasma, blood, and urine. We also evaluated parameters like head composition and dimension, stem offset, cup dimension, and stem-neck inclination. Cobalt concentrations remained minimal, with average blood and urine values being 0.8+0.6mcg/L (standard <1.8mcg/L) and 1.2+1.0mcg/L (standard <2.8mcg/L), respectively. Two individuals exhibited a slight increase in blood cobalt concentration by 0.1 and 0.2mcg/L. Chromium averages in blood and urine were also minimal, with readings of 0.9+0.2mcg/L (standard <1.2mcg/L) and 1.3 + 0.5mcg/L (standard <2mcg/L), respectively. One individual had a marginally increased blood chromium concentration of 1.3mcg/L. Evaluations considering ceramic or cobalt-chrome heads, up to a decade of follow up, or varying implant metrics showed negligible variations in metal ion concentrations. The findings reveal that over a minimum of five years (average = six years; span, five to 10 years), cobalt and chromium concentrations in patients' systems remained within normal limits and were clinically insignificant, irrespective of the follow-up duration, head material, or implant specifications. This underscores the efficacy of dual mobility systems in ensuring minimal metal ion presence.

Severe osteolysis in a patient with Legg-Calvé-Perthes disease 32 years after primary total hip replacement: A case report

This article presents a case report of a 73-year-old woman with Legg-Calvé-Perthes disease (LCPD) which developed late-onset osteolysis after a primary total hip replacement (THR). LCPD is a complex childhood hip disorder that can cause bone necrosis, deformation, and premature osteoarthritis with an increased risk of osteolysis after primary THR and therefore a higher risk of revision surgery. The acetabular component was unstable, with pronounced polyethene wear, and mechanical deformation and loosening of the acetabular component. The case was managed with the revision of THR using a non-cemented acetabular and femoral component, polyethene insert and ceramic head, which resulted in a smooth postoperative period. The article also discusses the incidence of LCPD and its association with osteolysis, highlighting the importance of considering medical history to manage complications after primary THR.

The Frank Stinchfield Award: Assembly and Dissociation Forces Differ Between Commonly Used Dual Mobility Implants: A Biomechanical Study

BackgroundIntraprosthetic dissociation (IPD) is a complication unique to dual mobility (DM) implants where the outer polyethylene head dissociates from the inner femoral head. Increasing reports of IPD at the time of closed reduction of large head DM dislocations prompted this biomechanical study evaluating the assembly and dissociation forces of DM heads. MethodsWe tested 17 polyethylene DM heads from 5 vendors. Of the heads, 12 were highly cross-linked polyethylene (4 vendors) and 5 were infused with vitamin E (2 vendors). Heads were between 46 and 47 mm in diameter, accepting a 28 mm-inner ceramic head. Implants were assembled and disassembled using a servohydraulic machine that recorded the forces and torques applied during testing. Dissociation was tested via both axial pull-out and lever-out techniques, where lever-out simulated stem-on-acetabular component impingement. ResultsThe initial maximum assembly force was significantly different between all vendors (P < .01) and decreased for all implants with subsequent assembly. Vendor 4-E (Link with vitamin E) heads required the highest assembly force (1,831.9 ± 81.95 N), followed by Vendor 3 (Smith & Nephew), Vendor 5 (DePuy Synthes), Vendor 1-E (Zimmer Biomet with vitamin E), Vendor 2 (Stryker), and Vendor 1 (Zimmer Biomet Arcom). Vendor 4-E implants showed the greatest dissociation resistance in both pull-out (2,059.89 N, n = 1) and lever-out (38.95 ± 2.79 Nm) tests. Vendor 1-E implants with vitamin E required higher assembly force, dissociation force, and energy than Vendor 1 heads without vitamin E. ConclusionsThere were notable differences in DM assembly and dissociation forces between implants. Diminishing force was required for assembly with each additional trial across vendors. Vendor 4-E DM heads required the highest assembly and dissociation forces. Vitamin E appeared to increase the assembly and dissociation forces. Based on these results, DM polyethylene heads should not be reimplanted after dissociation, and there may be a role for establishing a minimum dissociation energy standard to minimize IPD risk.

Hip Arthroplasty in Young Patients: Analysis of the New Zealand Joint Registry

Purpose: The aim of this study was to look into the New Zealand Joint Registry (NZJR) data on total hip arthroplasty (THA) in paediatric and adolescent patients aged 20 and under. Specifically, indications for THA, trends in implants and outcome data. Methods: An analysis of all patients aged 20 and under, recorded in the NZJR from December 1999 until January 2021. Review of similar international reports and NZ adult data undertaken. Results: We identified 115 THA performed in patients aged 20 and under in the NZJR. Mean age at primary surgery is 17.9 years. Indications included avascular necrosis (24%), fracture (6%), tumour (3.5%), inflammatory conditions (16.4%), post-infective (6.1%), SUFE (8.7%) and various other disorders. A total of 9/115 THA were reported as being revised in the study period with a revision rate per 100 component years of 0.69. Bearing surface has trended towards ceramic heads. Cementless implants have been the most commonly utilized. The approach is almost exclusively posterior (79%). Head size has increased from formerly being 28 or less to now 32 and above. Conclusions: Rates of THA in this population remain very low, in keeping with international data. Indications are similar to those seen in other registry studies. Trends mimic those seen internationally and in adult cohorts with cementless implants and larger ceramic heads being favored. Revisions were recorded in 9/115 patients with polywear being the most common indication. Outcome measures were excellent with a mean Oxford hip score of 37.4 at 6 months post operatively.