Fourth-generation ceramic-on-ceramic THA results in improvements in midterm outcomes compared to third-generation THA but does not resolve noise problems: a cohort study of a single-hip system

Bearing-Related Complications of Total Hip Arthroplasty Using Fourth-Generation Ceramic-On-Ceramic Articulations: Does Articular Noise Increase Over Time?

BACKGROUND

We previously reported the mean 6-year outcomes of total hip arthroplasty (THA) using fourth-generation ceramic-on-ceramic (CoC) articulations. With extended observations, this study aimed to report the mean 12-year outcomes focusing on bearing-related complications of CoC THA.

METHODS

We reviewed primary CoC THAs performed between May 2009 and April 2012 at a single institution. Of the 831 hips (739 patients), 716 hips (635 patients) that satisfied a minimum 10-year follow-up were included. The mean age at operation was 54 years (range, 16 to 83). The occurrence of bearing-specific complications, including ceramic fractures and noise generation, was evaluated. The mean follow-up duration was 12 years (range, 10 to 14).

RESULTS

A total of 2 (0.3%) ceramic liner fractures occurred, as previously reported. No additional ceramic fractures were observed during the extended follow-up period. However, the cumulative incidence of audible noise increased from 6.4 (48 of 749) to 8.2% (59 of 716). Of the 59 hips with noise, 26 (44.1%) developed noise within 1 year, whereas 13 (22.0%) presented with noise more than 5 years after THA. The noise was described as clicking in 35 hips (4.9%) and as squeaking in 24 hips (3.4%). No revision surgeries were performed for noise, except in 2 cases of concomitant liner fractures. The implant survivorship free of any revision was 98.1% at 12 years.

CONCLUSIONS

No additional ceramic fractures were identified in this extension study at a minimum follow-up of 10 years. However, the prevalence of articular noise has increased from 6.4 to 8.2% since the previous report. Possible late-onset noise should be considered when performing CoC THA in younger patients.

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

Purpose

To assess utility, benefits, and risks of 4th-generation alumina-zirconia ceramic pairings in elective total hip arthroplasty (THA).

Methods

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.

Results

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.

Conclusion

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.

Lower Revision Rates and Improved Stability With a Monoblock Ceramic Acetabular Cup

BACKGROUND

Monoblock ceramic cups are designed to accommodate large-diameter femoral heads. This has the potential to offer the advantages of an increased range of motion and enhanced joint stability. These features could benefit younger and high-demand patients in need of total hip arthroplasty. The aim of this study was to assess the survival rate and the reasons for revision of the DeltaMotion cup.

METHODS

Data from the AOANJRR were analyzed for all patients who had undergone a primary conventional THA performed between January 1, 2001 and December 31, 2021. Only prostheses with ceramic/ceramic, ceramic/XLPE, metal/XLPE, or CM/XLPE bearing surfaces were included. The primary outcome measure was the cumulative percent revision for all causes. Secondary outcome measures were revision for dislocation/instability, ceramic breakage, or noise. A subanalysis for cup size was also performed.

RESULTS

There were 486,946 primary conventional THA procedures undertaken for any reason. Of these, 4,033 used the DeltaMotion cup and 482,913 were modular designs. The DeltaMotion cup had the lowest CPR for all diagnoses compared to the modular bearings at all time points, had a significantly lower revision rate for prosthesis dislocation and no revisions for squeaking compared to other modular bearings. There were 175 ceramic breakages recorded in the modular bearing group and 1 ceramic breakage in the DeltaMotion group.

CONCLUSIONS

The DeltaMotion cup had a low rate of all-cause revision, and for dislocation, ceramic breakage, and noise. Although this cup is no longer manufactured, ongoing follow-up of newer monoblock ceramic cups will determine their suitability for younger and more active patients.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Forte ceramic-on-delta ceramic cementless total hip arthroplasty: an 8- to 15-year follow-up study

INTRODUCTION

Forte ceramic head on delta ceramic liner articulation showed satisfactory midterm results without ceramic-related complication. We aimed to investigate the clinical and radiological outcomes of cementless total hip arthroplasty (THA) with forte ceramic head on delta ceramic liner articulation.

MATERIALS AND METHODS

Overall, 107 patients (57 men, 50 women; 138 hips) who underwent cementless THA with forte ceramic head on delta ceramic liner articulation were enrolled. The mean follow-up duration was 11.6 years. For the clinical assessments, Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), presence of thigh pain, and presence of squeaking were evaluated. Radiographs were assessed to search for osteolysis, stem subsidence, loosening of implants. Kaplan-Meier survival curves were evaluated.

RESULTS

The mean HHS and WOMAC improved from 57.1 and 28.1 preoperatively to 81.4 and 13.1 at the final follow-up, respectively. Nine revisions (6.5%) were performed; 5 hips for stem loosening, 1 hip for ceramic liner fracture, 2 hips for periprosthetic fracture, and 1 hip for progressive osteolysis around cup and stem. Thirty-two patients (37 hips) complained squeaking, in which 4 cases (2.9%) were identified as ceramic-related noises. After a mean follow-up period of 11.6 years, 91% (95% CI 87.8-94.2) were free from revision of both femoral and acetabular components due to any reason.

CONCLUSIONS

Cementless THA with forte ceramic-on-delta ceramic articulation showed acceptable clinical and radiological results. Serial surveillance of these patients should be performed due to the possibility of cerami- related complications such as squeaking, osteolysis, and ceramic liner fracture.

Outcomes of Ceramic-On-Ceramic Bearing Total Hip Arthroplasty: A Minimum 10-Year Follow-Up Study

BACKGROUND

Although the fourth generation of ceramics has demonstrated excellent clinical results 5 to 6 years postoperatively, concerns over ceramic fracture and squeaking persist and longer-term follow-up (minimum 10 years) studies are warranted. Our study aimed to evaluate the minimum 10-year clinical outcomes and bearing-specific complications of ceramic-on-ceramic (CoC) total hip arthroplasties.

METHODS

We retrospectively evaluated all patients who underwent primary delta CoC total hip arthroplasty in our institution between January 2004 and February 2013. Demographics, surgical techniques, complications, patient-reported outcomes, and radiographic outcomes were collected and analyzed. For continuous variables, the comparison between groups was conducted using a one-way analysis of variance. Of all 235 patients included in the study, 70.5% were women (190 hips). The mean follow-up period was 12 years (range, 10 to 18). The femoral head sizes of 28- mm, 32 mm, and 36 mm were used in 50, 26, and 197 cases, respectively. Mean acetabular inclination and anteversion angles were 39.2 ± 7.1° and 14.9 ± 3.5°.

RESULTS

There were 5 hips revised at a mean 4.6 years (range, 0.1 to 7.1). One revision was squeaking-related. Squeaking was also reported by 8 other patients, but did not require revision. Other reasons for revision were early infection in 2 cases, stem loosening in 1 case, and stem fracture in 2 cases. The survival analysis for any causes for revision as an endpoint was 96.7% (95% confidence interval 0.313%-2.57%).

CONCLUSION

We report excellent mean 12-year follow-up results regarding the complications and survivorship of the fourth generation CoC bearings.

A Nomogram That Characterizes a Patient's Odds of Developing Squeaking After Fourth-generation Ceramic-on-ceramic THA

BACKGROUND

Although ceramic-on-ceramic (CoC) bearings result in the lowest wear rate of any bearing combination, postoperative squeaking remains worrisome. However, data concerning squeaking in long-term follow-up studies are still lacking, especially for fourth-generation CoC THA.

QUESTIONS/PURPOSES

(1) After keeping the prosthesis in place for 10 years, what percentage of patients treated with fourth-generation CoC THA implants report squeaking, and are there points in time when squeaking occurs more frequently? (2) What are the characteristics, association with hip function, and factors associated with squeaking? (3) Can we create a nomogram that characterizes a patient's odds of experiencing squeaking based on the factors associated with it?

METHODS

Between January 2009 and December 2011, 1050 patients received primary THAs at our institution, 97% (1017) of whom received fourth-generation CoC THAs because this was the preferred bearing during this period. Of the 1017 eligible patients, 5% (54) underwent THAs performed by low-volume surgeons, 3% (30) were implanted with cemented prostheses, 2% (22) died, 1% (10) were immobile, 1% (six) underwent revision surgery, and 17% (169) were lost to follow-up before 10 years, leaving 726 patients for analysis here at a mean of 11 ± 1 years. In the study cohort, 64% (464) were male and 36% (262) were female, with a mean age of 44 ± 13 years at primary THA. We extracted data about articular noise from follow-up records in our institutional database and used a newly developed questionnaire to ascertain the percentage of patients who reported squeaking at the latest follow-up interval. Although not validated, the questionnaire was modeled on previous studies on this topic. The longitudinal pattern for squeaking was explored to find timepoints when squeaking occurs more frequently. Based on the questionnaire data, we calculated the percentages of frequent, reproducible, and avoidable squeaking. Hip function was evaluated with the Harris Hip Score and WOMAC score and compared between the squeaking and nonsqueaking groups. Factors associated with squeaking, which were examined in a multivariate analysis, were used to develop a nomogram.

RESULTS

At 10 years, 16% (116 of 726) of patients reported squeaking. Two squeaking peaks were determined, at 0 to 1 year and 8 to 10 years. Frequent, reproducible, and avoidable squeaking accounted for 42% (36 of 86), 20% (17 of 86), and 41% (35 of 86), respectively. The mean Harris Hip Score (93 ± 4 versus 94 ± 5; p = 0.81) and WOMAC score (16 ± 13 versus 15 ± 13; p = 0.23) did not differ between patients with squeaking and those without. After controlling for potential confounding variables such as etiology and head offset, we found that patients younger than 46 years (odds ratio 2.5 [95% confidence interval 1.5 to 5.0]; p < 0. 001), those who were male (OR 2.0 [95% CI 1.1 to 3.5]; p = 0.04), those having a total flexion and extension arc of less than 50° (OR 2.0 [95% CI 1.2 to 3.3]; p = 0.02), and those with the Corail hip implant (OR 4.1 [95% CI 2.1 to 7.7]; p < 0. 001) were more likely to report squeaking. We created a nomogram that can be used at the point of care that can help clinicians identify patients at a higher risk of experiencing squeaking; this nomogram had good performance (area under the receiver operating characteristic curve of 77%).

CONCLUSION

As a potential late complication, squeaking after fourth-generation CoC THA is of concern and may be related to increased stripe wear. We recommend that surgeons use this nomogram to assess the odds of squeaking before selecting a bearing, especially in patients at high risk, to facilitate shared decision-making and improve patient satisfaction. Future external validation of the model is still needed to enhance its applicability.Level of Evidence Level III, therapeutic study.

Revision total hip arthroplasty by a ceramic bearing surface after a third- and fourth-generation ceramic head or liner fracture

PURPOSE

Although rare, fractures of ceramic components are difficult to revise, mainly due to the presence of residual ceramic debris that can cause catastrophic wear of the replacement components. Modern ceramic-on-ceramic bearings are suggested to improve outcomes of revision total hip arthroplasty (THA) for ceramic fractures. However, there are few published reports of mid-term outcomes of revision THA using ceramic-on-ceramic bearings. We evaluated clinical and radiographic outcomes of 10 patients who received ceramic-on-ceramic bearings during revision THA for ceramic fractures.

METHODS

All patients but one received fourth-generation Biolox Delta bearings. Clinical evaluation was performed using the Harris hip score at latest follow-up, and all patients received a radiographic evaluation to analyze the fixation of the acetabular cup and of the femoral stem. Osteolytic lesions and the presence of ceramic debris were noted.

RESULTS

After a mean follow-up of 8.0 years, there were no complications or implant failures, and all patients reported satisfaction with their implant. The average Harris hip score was 90.6. There was neither osteolysis nor loosening, but despite our extensive synovial debridement, ceramic debris was noted in the radiographs of five patients (50%).

CONCLUSION

We report excellent mid-term outcomes, with no implant failures after eight years despite ceramic debris being found in a significant proportion of patients. We conclude that modern ceramic-on-ceramic bearings are an advantageous option for the revision of THA due to the fracture of initial ceramic components.

A 10- to 12-year follow-up study of delta ceramic-on-ceramic total hip arthroplasty

BACKGROUND

We previously reported five-to-seven-year results of total hip arthroplasty (THA) with the use of delta ceramic-on-ceramic (CoC) bearing. We conducted an extension study with a CT scan at a minimum of 10 years after surgery.

METHODS

From March 2009 to March 2011, 273 patients (310 hips) received cementless THA with delta CoC bearing, porous-coated cup and hydroxyapatite-coated stem. In this extended study, 252 patients (144 men and 108 women) (288 hips) with a mean age of 49.7 years (16-83) at surgery were followed for a mean of 10.4 years (10-12) with CT scans in 133 hips (46.2%, 133/288). Clinical and radiographic evaluations were made at each follow-up and Kaplan-Meier survival analysis was performed with revision and reoperation as endpoints.

RESULTS

There were no more ceramic fractures. Compared to mid-term results, the incidence of squeaking and RLLs increased to 3.1% (9/288) and 19.4% (56/288), respectively. The RLL progressed to focal osteolysis in 3 hips (5.4%, 3/56). No hip had detectable wear or prosthetic loosening. Two hips were reoperated due to periprosthetic joint infection and periprosthetic femoral fracture in each. The survivorship decreased to 98.3% (96.7-99.9%) at 12 years.

CONCLUSION

During the extended follow-up, no additional ceramic fracture occurred, and the incidence of squeak increased by 0.7%. The long-term survivorship of Delta CoC THA was encouraging. However, focal osteolysis occurred around the hydroxyapatite-coated stem in 1% (3/288).

LEVEL OF EVIDENCE

II (Prospective cohort study).

Ten-year survival of ceramic-on-ceramic total hip arthroplasty in patients younger than 60 years: a systematic review and meta-analysis

Background

Total hip arthroplasty (THA) with ceramic-on-ceramic (CoC) was created to minimise wear debris and aseptic loosening. A decade ago, a meta-analysis showed a 10-year survival rate of just 89%. Based on the excellent tribology of the current CoC, significant improvement of implant survivorship is expected. In patients younger than 60, we conducted a meta-analysis to assess 10-year survival and complications after using current primary CoC THA.

Materials and methods

PubMed, Scopus, EMBASE, Virtual Health Library, and Cochrane Library were used to scan for published trials that met the inclusion criteria until January 2019. The qualified studies were subjected to a systematic review and proportional analysis, and the randomised controlled trials (RCTs) were included in a comparison meta-analysis.

Results

Thirteen studies were included 156 findings. The total number of hips was 2278. Nine studies were cohort, and four were RCTs between ceramic and polyethylene cups. The analysis revealed an average age of 44 years (range 24–54). The 10-year survival 96% (95% CI; 95.4–96.8%), aseptic loosening rate 0.516. (95% CI; 0.265–0.903), ceramic fracture rate 0.620 (95% CI; 0.34–1.034) and squeaking rate 2.687 (95% CI; 1.279–4.593). A comparison meta-analysis revealed the risk ratio (RR) for revision was 0.27 (95% CI; 0.15–0.47), and for aseptic loosening 0.15 (0.03–0.70) favouring CoC, while RR for component fracture was 1.62 (95% CI; 0.27–9.66) favouring the polyethylene.

Conclusion

In patients under sixty, current CoC THAs are correlated with better 10-year outcomes than before and have high survivorship rates.

Level of evidence: Level I.

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.

Survivorship of Ceramic-on-Ceramic Total Hip Arthroplasty With Metal-Backed Acetabular Liners at 10 Years

BACKGROUND

Ceramic-on-ceramic bearings are becoming increasingly popular in primary total hip arthroplasty (THA). To enhance ceramic-on-ceramic liner exchange in case of revision surgery, metal-backed liner systems have been proposed. Little is known about the clinical performance of these implants. The purpose of this study is to evaluate a metal-backed liner implant system for primary THA.

METHODS

A total of 422 patients (with 468 consecutive THAs) were followed over a mean period of 10 years. All arthroplasties were performed with a cementless stem, a press-fit cup, and a metal-backed liner system. Surgical and clinical data, complications, and revisions were analyzed. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) before surgery and at 1 and 10 years after surgery were compared.

RESULTS

The overall 10-year implant survival rate was 93.8%. The survival rate was 97.0% for heads and liners, 97.5% for stem, and 99.3% for acetabular cup. The most common reason for revision was ceramic breakage (2.4%) of the third-generation (BIOLOX forte) acetabular liner. Mean WOMAC score improved significantly from 50.1 before surgery to 13.2 at 1 year after surgery. There was no difference in WOMAC scores between surgical approach and type of bearing at 1 and 10 years after surgery.

CONCLUSION

THA using cementless stem, press-fit cup, and metal-backed liner system provides satisfactory long-term outcomes, with revision rate comparable to that with other systems available in the market. The metal-backed liner system has low risk of mal-seating. Third-generation ceramic liners should be avoided as they seem to be more prone to breakage.

National Trends in Total Hip Arthroplasty Bearing Surface Usage in Extremely Young Patients Between 2006 and 2016

Background

Long-term implant durability is a key concern when considering total hip arthroplasty (THA) in young patients. The ideal bearing surface used in these patients remains unknown. The purpose of this study was to analyze trends in THA bearing surface use from 2006 to 2016 using a large, pediatric national database.

Methods

This was a retrospective review from January 1, 2006, to December 31, 2016, using the Kids’ Inpatient Database. International Classification of Diseases, 9^th revision and 10^th revision codes were used to identify patients who underwent THA and create cohorts based on bearing surfaces: metal-on-metal, metal-on-polyethylene, ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC). Annual utilization of each bearing surface and associated patient and hospital demographics were analyzed.

Results

A total of 1004 THAs were identified during the 11-year study period. The annual number of THAs performed increased by 169% from 2006 to 2016. The mean patient age was 17.1 years. The most prevalent bearing surface used in 2006 was CoC (37.3%), metal-on-metal (31.8%) in 2009, and CoP in 2012 and 2016 (50.6% and 64.8%, respectively). From 2006 to 2016, utilization of CoP increased from 5.0% to 64.8%, representing a 1196% increase over the study period.

Conclusions

The number of THAs performed in pediatric patients is increasing significantly. Although CoC was previously the most commonly used bearing surface in this patient population, CoP is currently the most common. Further investigation is needed to determine whether bearing longevity and clinical outcomes with CoP are superior to other bearing surfaces.

Articular Noise After THA Using Delta CoC Bearings Has Little Impact on Quality of Life

BACKGROUND

To report clinical outcomes and survival at a minimum of 10 years of a consecutive series of uncemented total hip arthroplasty (THA) with fourth-generation ceramic-on-ceramic (CoC) bearings and determine the incidence of articular noises, their risk factors, and impact on quality of life (QoL).

METHODS

From a series of 456 CoC THAs, there were 25 revisions, 38 deceased, and 36 lost to follow-up. The remaining 357 hips were assessed at 11.1 ± 0.7 years (range, 10-14) using the Forgotten Joint Score, Oxford Hip Score, and a questionnaire on articular noises. Kaplan-Meier survival was calculated, and multivariable analysis was performed to determine associations between articular noise and patient/surgical factors.

RESULTS

The 10-year survival was 96.3% for the cup, 96.5% for the stem, and 94.2% for all components. The Forgotten Joint Score was 79 ± 26 (range, 0-100), and Oxford Hip Score was 16 ± 7 (range, 12-60). The mean impact of articular noises on QoL was 1.8 ± 2.9 (range, 0-9): considered negligible in 60 hips (16%), moderate in 27 hips (7%), and severe in only 13 hips (4%). Multivariable analyses revealed that the incidence of articular noise decreased with age (odds ratio [OR], 0.94; P = .001), body mass index (OR, 0.85; P = .001), and in hips implanted with 32-mm (vs 36 mm) heads (OR, 0.18; P = .030).

CONCLUSION

Of 100 hips (28%) that reported some articular noises 10 years after CoC THA, the impact of articular noises on QoL was negligible for most patients. Although larger heads can improve mobility and reduce risks of dislocations, surgeons must be aware that increasing head size could also increase risks of articular noises, notably in young and active patients.

Impingement Between the Metal Stem and the Ceramic Liner in Total Hip Arthroplasty: The Neck Is Not the Only Place Where Impingement Occurs

BACKGROUND

It is assumed that impingement between the ceramic liner and the stem increases the possibility of a liner fracture in total hip arthroplasty with a ceramic-on-ceramic bearing. The purpose of this study was to analyze the pattern of the impingement by evaluating the notches (U-shaped indented wear scars engraved on the stem) on radiographs to determine when and where impingement develops and to analyze the factors affecting its occurrence.

METHODS

Among the primary total hip arthroplasty cases using a ceramic-on-ceramic bearing performed from November 1997 to December 2003, 244 cases of 197 patients (123 male patients and 74 female patients) that had follow-up of ≥15 years were included. All of the radiographs were examined with special regard to the notches and the cup positions.

RESULTS

Notches were detected at 77 sites of 57 cases (23.4%) for the first time between 8 months and 14.8 years after the surgical procedure. They were located on the neck or the shoulder of the stem. Shoulder notches were detected only in the cases with a short-neck head. Shoulder notches were found in 29 cases (20.0% of short-neck cases). Cup inclination was lower (p = 0.01) and anteversion was higher (p = 0.01) in the group with notches than the group without notches. There were 5 cases of ceramic head fracture. One of them experienced another ceramic liner fracture, assumed to be caused by prosthetic shoulder impingement, after the revision surgical procedure.

CONCLUSIONS

The results of this study suggest that impingement between the stem and the ceramic liner occurs in a considerable proportion of patients who underwent total hip arthroplasty not only on the neck but also on the shoulder of the stem. Forceful and abrupt impingement on the stem shoulder can cause ceramic liner fracture. Impingement between the stem shoulder and the ceramic liner should be considered in designing a stem. It seems to be prudent to recommend that patients avoid squatting or sitting cross-legged on the floor as much as possible.

LEVEL OF EVIDENCE

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

Ceramic-on-ceramic vs ceramic-on-polyethylene, a comparative study with 10-year follow-up

BACKGROUND

In press-fit total hip arthroplasty (THA) ceramic-on-ceramic (CoC) bearings are a potential for overcoming the wear that is seen in ceramic-on-polyethylene (CoPE) bearings, and can lead to wear-induced osteolysis, resulting in loosening of the implant. However, CoC bearings show disadvantages as well, such as squeaking sounds and being more fragile, which can cause ceramic head or liner fracture. Because comparative long-term studies are limited, the objective of this study was to determine the long-term difference in wear, identify potential predictive factors for wear, investigate radiological findings such as osteolysis, and evaluate clinical functioning and complications between these bearings.

AIM

To determine 10-year differences in wear, predictive factors for wear, and investigate radiological findings and clinical functioning between CoC and CoPE.

METHODS

This observational prospective single-center cohort study with a 10-year follow-up includes a documented series of elective THAs. Primary outcome was wear measured by anteroposterior (AP) radiographs. Secondary outcomes were potential predictive factors for wear, complications during follow-up, Harris hip score (HHS), and radiological findings such as presence of radiolucency, osteolysis, atrophy, and hypertrophy around the cup. Due to the absence of wear in the CoC group, stratified analysis to identify risk factors for wear was only performed in the CoPE group by use of univariate linear regression analysis. HHS was expressed as a change from baseline and the association with bearing type was assessed by use of multivariate linear regression analysis, adjusted for potential confounders.

RESULTS

A total of 17 CoPE (63.0%) and 25 CoC (73.5%) cases were available for follow-up and showed a linear wear of respectively 0.130 mm/year (range 0.010; 0.350) and 0.000 mm/year (range 0.000; 0.005), which was significant (P < 0.001) between both groups. Wear always occurred in the cranial direction. Cup inclination was the only predictive factor for polyethylene (PE) wear. No dislocations, ceramic head, or liner fractures were seen. The HHS showed a mean change from baseline of 37.1 points (SD 18.5) in the CoPE group and 43.9 (SD 17.0) in the CoC group. This crude difference of 6.8 (range -5.2; 18.7) in favor of the CoC group was not significant (P = 0.26) and was not significant when adjusted for age, gender, and diagnosis either (P = 0.99). No significant differences in complications and radiological findings were seen between groups.

CONCLUSION

CoC bearing shows lower wear rates compared to CoPE at 10-year follow-up with cup inclination as a predictive factor for wear and no differences in complications, HHS, and radiological findings.

Mid-term outcomes of the R3™ delta ceramic acetabular system in total hip arthroplasty

Background

Whilst bony fixation of hip replacement has stable solutions, there remains controversy over which bearing best optimizes longevity and function. Ceramic-on-ceramic (CoC) bearing combinations are associated with lower risk of revision due to aseptic loosening and dislocation. Evidence for long-term functional outcomes of modern, 4th generation CoC bearings is limited. The aim of this study was to analyze outcomes and complications of the R3™ Acetabular System (Smith & Nephew, Inc., Cordova, TN, USA) in combination with BIOLOX® Delta ceramic femoral head in patients undergoing primary total hip arthroplasty (THA).

Methods

Between June 2009 and May 2011, 175 patients (178 hips) were enrolled into a prospective, study at 6 sites in Europe and prospectively followed-up at 3 months and 1, 3, 5, and 7 years postoperative.

Results

Total WOMAC score improved from 63 (range, 22–91) preoperative to 8 (range, 0–8) at 1-year follow-up and remained unchanged at 7-year follow-up. Modified Harris hip score improved from 45 (range, 10–87) preoperative to 83 (range, 25–100) at 3 months, 91 (range, 42–100) at 1 year, and 92 (range, 46, 100) at 7 years. UCLA Activity Rating Scale score improved from 3.3 (range, 1–8) preoperative to 6.2 (range, 2–8) at 1 year; it marginally declined to 5.8 (range, 3–8) at 7-year follow-up. There were 4 trochanteric fractures and 5 patients died of unrelated reasons. Three hips were revised (2 periprosthetic fractures and 1 subluxation). The 7-year cumulative survival rate was 98.3%.

Conclusion

Clinical and functional improvements of THA with CoC bearing are maintained at 7 years postoperative.

Trial registration

ClinicalTrials.Gov, NCT03566082, Registered 10 January 2018—retrospectively registered,

Whole blood titanium metal ion measurement reproducibility of two laboratories

Background

Metal ion blood concentrations evaluation can be useful in monitoring wear and corrosion of orthopedic implants. Elevated metal ion level may help detecting defective hip arthroplasty implants and serve as an indicator for revision surgery. Our objective was to evaluate the reproducibility of titanium metal ion level measurements by two different laboratories.

Methods

Seventy-one whole blood samples were collected from 64 patients with unilateral ceramic-on-ceramic hip arthroplasty. For each patient, two whole blood samples were collected and analyzed in two different laboratories.

Results

For each case, laboratory 1 had significantly higher values than laboratory 2. There was a clinically significant absolute difference between the two laboratories, above the predetermined threshold, for 90% of samples. A mean variation ratio of 410% between the two laboratories was found.

Conclusion

Not all laboratories use the same techniques and calibrations to perform these measurements. Therefore, their results should be interpreted with caution and clinical decision should rely on metal ion trends provided by the same laboratory.