Alumina-on-alumina ceramic versus metal-on-highly cross-linked polyethylene bearings in total hip arthroplasty: a comparative study

Ceramic-on-ceramic vs metal-on-crosslink polyethylene in a fully hydroxyapatite-coated total hip arthroplasty: Survivorship, complications and long-term results

Background

Few studies compare complications and results in ceramic-ceramic (CeCe) vs metal-on-crosslink polyethylene (Me-XLPE) hip prosthesis.

Methods

Prospective, non-randomized, observational analysis of 2 series of hydroxyapatite-coated Furlong Active implanted with identical protocol by 1 surgeon in 1 hospital from 2006 to 2014.

Bearing surface

CeCe (Biolox Forte/Delta) in 35 cases of 53.7 ± 10.6 years (25-69) (21 males, 60 %), Me-XLPE in 65 of 69.0 ± 8.9 years (42-81) (36 males, 55 %); age was different (p < 0.00001), but not sex (p = 0.6565). Head diameter: 28 mm in 19, 32 mm in 9 and 36 mm in 7 CeCe hips; 28 mm in 63, 32 mm in 1 and 36 mm in 1 Me-XLPe hips.

Follow-up

10.5 ± 3.1 years (1-15) in ceramic, 9.8 ± 3.8 years (2-15) in Me-XLPE.

Results

Survivorship without additional surgery or closed reduction at 15 years: 91.0 % in ceramic, 83.8 % in Me-XLPE joints. Survivorship without component exchange at 15 years: 93.9 % in ceramic, 93.6 % in Me-XLPE joints.

Complications

CeCe joints suffered 2 infections, 1 isolated dislocation, and 1 Vancouver-C fracture. Me-XLPE joints presented 2 infections (p = 0.6101), 5 isolated (p = 0.6621) and 2 recurrent dislocations (p = 0.5454), and 4 Vancouver-B fractures (p = 0.6548).At final follow-up, Harris Hip Score averaged 93.2 ± 13.7 (23-100) in ceramic and 94.3 ± 8.7 (65-100) in XLPE joints (p = 0.64552).Measured radiographic wear reached 0.06 ± 0.38 mm (0-1.5) (0.0057 mm/year) in CeCe and 0.16 ± 0.5 mm (0-2) (0.0163 mm/year) in Me-XLPE (p = 0.30302). At final radiographic follow-up, osteolysis was present in 8 Charnley-De Lee zones (6 patients) (17 %) of ceramic cups and in 25 zones (15 patients) (23 %) of XLPE cups (p = 0.980127).

Conclusion

At 10 years follow-up, metal-XLPE and ceramic-ceramic joints in Furlong-H-A.C. Active present no significant differences in complications, clinical score, wear, acetabular osteolysis, or survivorship without component exchange.Nevertheless, survivorship without any surgery or closed reduction is different because of the high rate of dislocation in 28 mm metal-poly joints.

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.

Seven-Year Longitudinal Study: Clinical Evaluation of Knee Osteoarthritic Patients Treated with Mesenchymal Stem Cells

Background/Objectives: Numerous studies have demonstrated the safety and efficacy of intraarticular stem cell injections for treating osteoarthritic knee joints, reporting symptom reduction and pain relief within a few months of treatment. Here, we report the results of a 7-year follow-up after a single intraarticular injection of 0.5-1 × 107 autologous adipose tissue-derived mesenchymal stem cells in patients with OA (Kellgren-Lawrence grade 2 to 4). Methods: Nine patients were treated, and two patients had bilateral disease. Patients were evaluated clinically and radiologically using X-ray and MRI. A comprehensive statistical analysis was undertaken to evaluate the obtained results. Results: All clinical scores and range of motion significantly improved within the first six months after injection. At the 18-month time point, a significant improvement in cartilage structure was observed on MRI while X-ray showed no changes in subchondral bone of distal femur and proximal tibia. At the 60-month time point, the clinical scores were still improved compared to baseline, except for the range of motion, which decreased almost back to the baseline level. At 84 months, the clinical scores decreased significantly toward the baseline level, but the MRI structural characteristics of cartilage still remained significantly better than those measured at baseline. Conclusions: Adipose tissue-derived stem cell therapy has substantial long-term clinical effects on patients with knee osteoarthritis.

Characterization of residual debris on packaged hip arthroplasty stems demonstrates the dominance of less than 10 μm sized particulate: Updated USP788 guidelines for orthopedic implants

Past evaluation of particle contamination on packaged implants has typically been conducted using US Pharmacopeia (USP) 788, a 1970s pharmaceutical guideline created to evaluate contaminant particles in injectable fluids and syringes. Our objective was to reestablish relevant acceptance criteria for residual orthopedic and other implant debris, including smaller particles (i.e., <10 μm in diameter). Packaged total hip arthroplasty (THA) titanium (Ti6Al4V)-alloy femoral stems were used (hydroxyapatite [HA]-coated and non-coated stems). Short-term ultrasonication and longer-term 24-hour soak/agitation methods were used to elute surface-bound contaminant particles, and released particles were analyzed via scanning electron microscopy, energy-dispersive x-ray analysis, image analysis, and particle characterization. For HA-coated THA-stems, >99% of eluted particles were calcium phosphate. For plain non-coated THA-stems, >99% of eluted particles were titanium-alloy-based. The number-based median size of particles in both groups was approximately 1.5 μm in diameter despite being composed of different materials. The total volume of particulate removed from HA-coated stems was 0.037 mm3 (671 × 103 particles total), which was approximately >50-fold more volume than that on plain non-coated stems at 0.0006 mm3 (89 × 103 particles total). Only non-coated THA stems passed reestablished USP788 acceptance criteria, compared by using equivalent total volumes of contaminant particulate within new and legacy guideline ranges of >10 and >25 μm ECD, that is, <1.0 × 107 particles for <1 μm diameter in size, <600,000 for <1-10 μm, <6000 for 10-25 μm and <600 for >25 μm. These results fill a knowledge gap on how much residual debris can be expected to exist on packaged implants and can be used as a basis for updating acceptance criteria (i.e., termed USP788-Implant [USP788-I]). Residual implant particulate assessment is critical given the increasing implant complexity and new manufacturing techniques (e.g., additive manufacturing).

Head, acetabular liner composition, and rate of revision and wear in total hip arthroplasty: a Bayesian network meta-analysis

Total hip arthroplasty (THA) is a common procedure for patients suffering from hip pain e.g. from osteoarthritis, osteonecrosis, or hip fractures. The satisfaction of patients undergoing THA is influenced by the choice of implant type and material, with one key factor being the selection of the appropriate material combination for the bearing surface. In this Bayesian network meta-analysis, we investigated the impact of material combinations for the bearing surface on the longevity of hip implants. The wear penetration rate per year and the total wear penetration in the liner resulting from different material combinations, as well as the survival rate at last follow-up, were examined. We analyzed a total of 663,038 THAs, with 55% of patients being women. Mean patient age was 59.0 ± 8.1 years and mean BMI 27.6 ± 2.6 kg/m2. The combination of an aluminium oxide (Al2O3) head and an Al2O3 liner demonstrated the lowest wear penetration at last follow-up and the lowest rate of wear penetration per year. Additionally, the combination of a crosslinked polyethylene (XLPE) liner and a zircon oxide (ZrO2) head demonstrated the lowest rate of revision at last follow-up. These findings underscore the importance of careful material selection for hip implant bearing surfaces to optimize their longevity and patient satisfaction after THA.

Comparisons of Different Bearing Surfaces in Cementless Total Hip Arthroplasty: A Systematic Review and Bayesian Network Analysis

BACKGROUND

We aimed to make comparisons of different bearing surfaces in patients after cementless total hip arthroplasty.

METHODS

The network meta-analysis was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guideline. The primary outcomes were implant survival and Harris hip score (HHS). Secondary outcomes included linear wear rates and serum level of metal ions. Subgroup analyses were performed by: (1) classifying head sizes as small and large; (2) femoral heads as ceramic and metal; and (3) liners as metal, ceramic, polyethylene, highly cross-linked polyethylene (HXP), or vitamin E-infused highly cross-linked polyethylene (HXPE). A total of 64 eligible RCTs with different bearings were assessed. Overall inconsistency and heterogeneity were acceptable.

RESULTS

In the 10 years follow-up, metal-on-polythene and ceramic-on-polythene bearings with small heads showed higher risk for revisions compared with metal-on-HXP and ceramic-on-HXP bearings with small heads. Similarly, only metal or ceramic-on-polythene bearings with small heads showed inferiority in HHS compared with other bearings. Conventional polyethylene liners showed higher linear wear rates compared with HXP, HXPE, and ceramic liners at 5 and 10 years after surgery, while metal-on-metal and ceramic-on-metal bearings showed higher serum level of cobalt and chromium.

CONCLUSION

Bearings containing HXP, HXPE, and ceramic liners showed comparable survivorship and hip function at follow-up of 5 and 10 years. Hard-on-hard bearings containing metal had higher serum level of metal ions than others. Bearings containing conventional polyethylene had worse performance in terms of implant survival, hip function, and wear rates.

LEVEL OF EVIDENCE

Level I.

Third-Generation Ceramic-on-Ceramic Total Hip Arthroplasty in Patients with Osteonecrosis of the Femoral Head: A 10- to 16-year Follow-up Study

BACKGROUND

Long-term follow-up results of ceramic-on-ceramic (COC) total hip arthroplasty (THA), specifically, in patients with osteonecrosis of the femoral head (ONFH) are unknown. We evaluated (1) clinical results and radiological outcomes, (2) ceramic-related complications: noise and ceramic fracture, (3) osteolysis, and (4) survivorship after alumina COC THA in ONFH patients with longer than 10-year follow-up.

METHODS

From May 2003 to June 2009, 325 ONFH patients (403 hips) underwent primary THAs at our department. Among them, 231 patients (293 THAs) were followed for 10 to 16 (mean, 12.9) years. There were 148 men and 83 women, their mean age at the time of THA was 47.2 years, and their mean body index was 24.0 kg/m2. The postoperative CT scans were done in 160 hips.

RESULTS

Grinding sensation or squeak was noted in 6.8% (20/293), ceramic head fracture occurred in 2.4% (7/293) and acetabular osteolysis developed in 0.7% (2/293). All 7 ceramic fractures occurred in 28-mm short-neck heads. There was no detectable wear or prosthetic loosening, and the 16-year survivorship was 96.0% (95% confidence interval; 93.8% to 98.2%). The mean Harris hip score was 91.7 (range, 84 to 100) points at the final follow-up.

CONCLUSIONS

The 10- to 16-year results of alumina COC THAs were encouraging with an excellent survivorship. However, ceramic fracture and noise still remain matters of concern. We recommend not to use 28-mm short-neck ceramic head to avoid ceramic head fractures.

LEVEL OF EVIDENCE

III.

Long-Term Outcomes of a Titanium-Encased Ceramic Liner Total Hip Arthroplasty (15 to 21Year Results)

BACKGROUND

Historically, aseptic loosening and osteolysis were responsible for most of the revisions among young and more active patients. Ceramic-on-ceramic bearings reduced wear but presented mechanical issues such ceramic fracture or liner chipping during insertion. To prevent this from happening a titanium-encased alumina liner was developed. The aim of this study is to address long-term results of this specific ceramic design.

METHODS

All patients received an uncemented acetabular component with ceramic-on-ceramic bearing (94 hips in 77 patients). Patients were prospectively followed over 15 years. Clinical evaluation included the Harris Hip Score and Visual Analog Scale pain scale. Radiographic analysis included integration, osteolysis, and ceramic-related mechanical issues, such as malseating of the insert.

RESULTS

The studied acetabular design survivorship was 98.9% at a mean follow-up of 17.2 years. One arthroplasty was revised secondary to infection but no cup had loosened or migrated during the study. Only 1 cup showed complete radiolucent lines. There was no fracture of any ceramic component in the study group. Malseating was present in 12 acetabular components (12.8%). No osteolysis was observed with over 15 years of follow-up.

CONCLUSION

In conclusion, this acetabular component demonstrates a favorable clinical and radiological outcome with over 15 years of follow-up. Osteolysis was not observed and incomplete seating of the titanium-sleeved ceramic liner did not lead to mechanical problems.

Fragility Index as a Measure of Randomized Clinical Trial Quality in Adult Reconstruction: A Systematic Review

Background

The Fragility Index (FI) and Reverse Fragility Index are powerful tools to supplement the P value in evaluation of randomized clinical trial (RCT) outcomes. These metrics are defined as the number of patients needed to change the significance level of an outcome. The purpose of this study was to calculate these metrics for published RCTs in total joint arthroplasty (TJA).

Methods

We performed a systematic review of RCTs in TJA over the last decade. For each study, we calculated the FI (for statistically significant outcomes) or Reverse Fragility Index (for nonstatistically significant outcomes) for all dichotomous, categorical outcomes. We also used the Pearson correlation coefficient to evaluate publication-level variables.

Results

We included 104 studies with 473 outcomes; 92 were significant, and 381 were nonstatistically significant. The median FI was 6 overall and 4 and 7 for significant and nonsignificant outcomes, respectively. There was a positive correlation between FI and sample size (R = 0.14, P = .002) and between FI and P values (R = 0.197, P = .000012).

Conclusions

This study is the largest evaluation of FI in orthopedics literature to date. We found a median FI that was comparable to or higher than FIs calculated in other orthopedic subspecialties. Although the mean and median FIs were greater than the 2 recommended by the American Academy of Orthopaedic Surgeons Clinical Practice Guidelines to demonstrate strong evidence, a large percentage of studies have an FI < 2. This suggests that the TJA literature is on par or slightly better than other subspecialties, but improvements must be made.

Level of Evidence

Level I; Systematic Review.

Incidence of Ceramic Fracture in Contemporary Ceramic-on-Ceramic Total Hip Arthroplasty: A Meta-analysis of Proportions

BACKGROUND

We performed a proportion meta-analysis of currently available data to determine the prevalence of ceramic fracture for each generation.

METHODS

A total of 10,571 total hip arthroplasties from 45 studies were included. Proportion meta-analysis with a random-effects model was performed to estimate the prevalence of ceramic fracture. To determine whether the ceramic fractures have a fatigue nature and a risk or latent period for the development, postoperative time lapse, patient age, and body mass index were related with ceramic fracture by metaregression analysis.

RESULTS

As of postoperative 2.0 to 18.8 years, the rate of ceramic fracture was 0.5% (95% CI, 0.3%-0.8%) in the forte group and 0.2% (95% CI, 0.1%-0.4%) in the delta group (P = .059). The ceramic fracture rate for each component was 0.2% (95% CI, 0.1%-0.3%) for the forte head, 0.1% (95% CI, 0.0%-0.2%) for the delta head (P = .210), 0.2% (95% CI, 0.1%-0.3%) for the forte liner, and 0.2% (95% CI, 0.1%-0.4%) for the delta liner (P = .305). The rate of ceramic fracture per 1000 patient-years was 0.9 (95% CI, 0.5-0.13) in the forte group and 0.5 (95% CI, 0.2-0.8) in the delta group (P = .072). In metaregression analysis, no significant associations were found between prevalence of ceramic fracture and postoperative time lapse, patient age, or body mass index.

CONCLUSIONS

The rate of ceramic fracture was 0.9/1000 patient-year in the forte group and 0.5/1000 patient-year in the delta group. The results of this study provide baseline data for further studies validating ceramic bearings.

LEVEL OF EVIDENCE

Level I, meta-analysis.

Eighteen-Year Follow-Up Study of 2 Alternative Bearing Surfaces Used in Total Hip Arthroplasty in the Same Young Patients

BACKGROUND

This study compares the long-term functional, radiographic, and computed tomography scan outcomes and implant survivorship of ceramic-on-ceramic total hip arthroplasty (C-O-C THA) and ceramic-on-highly cross-linked polyethylene total hip arthroplasty (C-O-HXLPE THA) in the same patients.

METHODS

In this randomized, prospective trial conducted between January 1999 and April 2003, 133 patients (266 hips) younger than 55 years were enrolled. Each patient received C-O-C THA in 1 hip and a C-O-HXLPE THA in the other. The mean follow-up was 17.1 years (range, 15-18 years); there were 84 men and 49 women with a mean age of 53 ± 7 years (range, 25-55 years).

RESULTS

At the latest follow-up, mean Harris hip scores (94 vs 93 points; P = .861), pain scores (43 vs 42 points; P = .651), and patient satisfaction scores (7.8 vs 7.6 points; P = .379) were not different between the 2 groups. Eight hips (3%) in the C-O-C THA had an audible squeaking sound. The mean annual penetration rate of HXLPE was 0.0162 ± 0.032 mm per year. No osteolysis was recorded on radiographs or computed tomography scans in either group. At 17.1 years, the survival rate of the acetabular component was 97% in the C-O-C bearing group and 98% in the C-O-HXLPE bearing group (P = .923). The survival rate of the femoral component was 99% in both groups.

CONCLUSION

Both C-O-C THA and C-O-HXLPE THA functioned well, with no osteolysis at mean of 17.1-year follow-up.

Comparison of Wear Rate between Ceramic-on-Ceramic, Metal on Highly Cross-linked Polyethylene, and Metal-on-Metal Bearings

Objective  Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal on highly cross-linked polyethylene (MoP), ceramic-on-ceramic (CoC), and metal-on-metal (MoM) bearings. Our aim was to calculate the 5- to 10-year wear rate and the incidence rate of osteolysis for 3 types of bearings.

Methods  A total of 77 patients underwent MoP, 105 underwent ceramic CoC, and 55 underwent MoM THAs. The average patient age at the time of surgery was 64.7, 55.9, and 59.9 years old in the MoP, CoC, and MoM bearings, respectively. Clinical and radiologic measurements at a mean follow-up of 7.6 years were analyzed.

Results  The mean postoperative Harris hip scores showed no difference among the groups. The mean annual liner wear rates were 0.0160, 0.0040 and 0.0054 mm/year in MoP, CoC bearings, and MoM bearings, with that of CoC bearings being significantly lower than the others. Osteolysis (14.5%) among MoM bearings was significantly more frequently observed compared with the others. Kaplan-Meier survival at 10 years with implant loosening, or revision THA as the endpoint, was 96.1% (95% confidence interval [CI]: 88.4–98.7) for MoP, 98.6% (95% CI: 90.3–98.6) for CoC bearing, and 98.2% (95% CI: 88.0–99.7) for MoM bearings ( p  = 0.360).

Conclusion  Excellent clinical and radiological outcomes were obtained for MoP and CoC bearings.

Same survival but higher rate of osteolysis for metal-on-metal Ultamet versus ceramic-on-ceramic in patients undergoing primary total hip arthroplasty after 8 years of follow-up

BACKGROUND

To avoid wear-induced osteolysis, ceramic-on-ceramic (CoC) and metal-on-metal (MoM) bearings have been developed. At present, there are no direct material related clinical comparisons between cementless total hip arthroplasty with CoC and MoM at more than 5-year follow-up. The bearing that is more likely to prevent osteolysis is still controversial. Therefore, we performed a retrospective case control study evaluating CoC and MoM cementless THAs in order to: - compare the longevity and complications for CoC and MoM THAs at 5-10 years postoperatively; - compare the incidence of osteolysis between both type THAs; - evaluate pseudotumors in MoM THAs.

HYPOTHESIS

CoC THAs will have a lower rate of osteolysis, better longevity, and better clinical outcomes than MoM THAs.

PATIENTS AND METHODS

Ninety-six hips underwent CoC THAs, and 56 hips underwent MoM THA (Ultamet, Pinnacle, Depuy). Average patient age at the time of surgery was 57.1 years (range, 28 to 77 years).

RESULTS

There were no differences with regard to the Harris hip score (89.5 and 90.3 for the CoC and MoM groups, respectively). Osteolysis (9 hips, 14.3%) among MoM THAs were significantly more frequently observed compared to CoC THAs (2 hips, 2.1%). Kaplan-Meier survival at 8 years with implant loosening or revision THA as the endpoint was 98.2% (95% CI: 87.8-99.8) for CoC, and 98.6% (95% CI: 90.2-99.8) for MoM (p=0.684). There was one audible squeaking (1.0%) and no ceramic fracture among CoC THAs. Five (8.9%) hips showed pseudotumors among MoM THAs.

DISCUSSION

CoC THAs had a low incidence of osteolysis. No significant difference was seen in the 8-year survival rate between implants, when using implant loosening and revision THA as endpoints. These data indicate that CoC THAs have excellent clinical and radiological outcomes, compared with MoM THAs. Ultamet MoM had a higher rate of osteolysis compared to other MoM bearings; the cup modularity (without polyethylene) and the use of 36mm heads as well as the process of production (after 2006) may play a significant role in the higher rate of osteolysis.

LEVEL OF EVIDENCE

III, Case control study, case control retrospective design.

Comparison of cementless total hip arthroplasty survivorship between metal-on-highly cross-linked polyethylene and ceramic on ceramic bearings: A case control study with a 5-9-year follow-up

BACKGROUND

Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal-on-highly cross-linked polyethylene bearing (MoXPE), ceramic on ceramic bearing (CoC) at more than 5 years follow-up. Therefore, we performed a case control study to: compare the incidence rate of osteolysis; compare the longevity for both types of THAs, and to evaluate the wear rate of MoXPE THAs.

HYPOTHESIS

CoC THAs will have a lower rate of osteolysis and better longevity than MoXPE THAs.

PATIENTS AND METHODS

We performed a retrospective analysis of 77 MoXPE (68 women, 9 men) and 105 CoC (85 women, 20 men) THAs, with an average patient age at the time of surgery of 64.7 years (range, 27 to 76 years). The cohorts were matched according to sex, body mass index, or diagnosis of hip joint disease. Clinical and radiologic measurements were analyzed at a mean follow-up of 6.7 years (range, 5-9 years).

RESULTS

There were no between-group differences with regard to the Harris hip score (87.0 [64.0-98.0] and 89.9 [70.0-100.0] for the MoXPE and CoC group, respectively) and the incidence rate of osteolysis (2.6% and 1.9%, respectively). Revision was required for 1 case for each THA type. The Kaplan-Meier survival at 8 years, using implant loosening or revision as the end-point of analysis, was 96.1% (95% confidence interval [CI], 90.0-99.3) for the MoXPE group and 98.9% (95% CI, 92.2-99.8) for the CoC group (p=0.189). The mean annual liner wear rate was 0.0160mm/year (range, 0.0050 to 0.0390mm/year) for the MoXPE THAs.

DISCUSSION

There was no difference between CoC and MoXPE THAs in the incidence of osteolysis or in survival rate at 8 years post-surgery. Excellent clinical and radiological outcomes were obtained for both types of bearings.

LEVEL OF EVIDENCE

III, Case control study, case control retrospective design.

The effect of bearing surface on risk of periprosthetic joint infection in total hip arthroplasty: a systematic review and meta-analysis

AIMS

Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty (THA). Different bearing surface materials have different surface properties and it has been suggested that the choice of bearing surface may influence the risk of PJI after THA. The objective of this meta-analysis was to compare the rate of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC) bearings.

PATIENTS AND METHODS

Electronic databases (Medline, Embase, Cochrane library, Web of Science, and Cumulative Index of Nursing and Allied Health Literature) were searched for comparative randomized and observational studies that reported the incidence of PJI for different bearing surfaces. Two investigators independently reviewed studies for eligibility, evaluated risk of bias, and performed data extraction. Meta-analysis was performed using the Mantel-Haenzel method and random-effects model in accordance with methods of the Cochrane group.

RESULTS

Our search strategy revealed 2272 studies, of which 17 met the inclusion criteria and were analyzed. These comprised 11 randomized controlled trials and six observational studies. The overall quality of included studies was high but the observational studies were at high risk of bias due to inadequate adjustment for confounding factors. The overall cumulative incidence of PJI across all studies was 0.78% (1514/193 378). For each bearing combination, the overall incidence was as follows: MoP 0.85% (1353/158 430); CoP 0.38% (67/17 489); and CoC 0.53% (94/17 459). The meta-analysis showed no significant difference between the three bearing combinations in terms of risk of PJI.

CONCLUSION

On the basis of the clinical studies available, there is no evidence that bearing choice influences the risk of PJI. Future research, including basic science studies and large, adequately controlled registry studies, may be helpful in determining whether implant materials play a role in determining the risk of PJI following arthroplasty surgery. Cite this article: Bone Joint J 2018;100-B:134-42.

Incidence of Ceramic Liner Malseating After Ceramic-on-Ceramic Total Hip Arthroplasty Associated With Osteolysis: A 5- to 15-Year Follow-Up Study

BACKGROUND

The aim of our study was to evaluate the clinical and radiographic outcomes of malseating of the acetabular liner in ceramic-on-ceramic total hip arthroplasty (THA).

METHODS

Outcomes for 160 ceramic-on-ceramic THAs, contributed by 116 women and 39 men, were evaluated. Clinical and radiographic measurements were obtained over a 5- to 15-year follow-up for analysis.

RESULTS

Liner malseating was identified in 20% of cases. Outcomes for 32 cases with liner malseating (group A) were compared to outcomes for 128 joints with correct liner seating (group B). The Harris hip score at the last follow-up was 90.1 for group A and 89.6 for group B. Osteolysis was identified in 5 cases in group A (15.6%), compared to 3 cases in group B (P < .001). No significant between-group differences were identified with regard to ceramic fracture, audible squeaking, loosening of components, and revision THA. The mean annual liner wear rate was comparable between groups, 0.0045 mm/y for group A and 0.0039 mm/y for group B. The 10-year Kaplan-Meier survivorship, based on an end point of revision THA, was 100% for group A and 99.0% for group B.

CONCLUSION

Over a moderate-length follow-up of 5-15 years, malseating of the acetabular liner was not associated with negative clinical outcomes or THA survivorship. Malseating did increase the incidence of osteolysis, a risk factor for adverse effects. Long-term follow-up studies are needed to fully quantify the effects of malseating of the acetabular liner.

Primary Total Hip Arthroplasty With Fourth-Generation Ceramic-on-Ceramic: Analysis of Complications in 939 Consecutive Cases Followed for 2-10 Years

BACKGROUND

Delta ceramics may be the bearing of choice for younger and active patients due to its improved toughness and wear characteristics, provided there is no risk of fracture. However, ceramic fracture is the most serious complication related to this type of bearing. Although millions of Delta ceramics have been implanted worldwide, short to midterm results have been scarcely reported in the literature. The purpose of this study was to report the complication rate at short to midterm follow-up associated with the bearing surface used in a series of primary total hip arthroplasties with Delta ceramic-on-ceramic bearings performed in a single institution.

METHODS

A total of 939 cases (880 patients) undergoing primary total hip arthroplasty with fourth-generation Delta ceramic-on-ceramic bearings were retrospectively reviewed. They were followed for an average of 5.3 years (2-10 years).

RESULTS

One hip experienced a liner fracture, 2 cups presented early loosening due to friction between the acetabular screw and the backside of the liner, one femoral ball head had a fracture; one case of squeaking was reported, which is impending revision. Considering revision or impending revision in relationship with the bearing surface as the end point, the mean survival rate was 99.3% (confidence interval 95%, 98.3%-99.7%) at 2-10 years.

CONCLUSION

This study showed a low rate of ceramic fracture compared with others; however, it was much higher than the complication rate presented by the manufacturers. The complications observed were directly related to technical errors that surgeons should avoid when using this type of surface.

Survivorship Between 2 Different Ceramic-on-Ceramic Total Hip Arthroplasty With or Without a Metal-Backed Titanium Sleeve Bearing: A 5- to 14-Year Follow-Up Study

BACKGROUND

The aim of the study was to compare the clinical and radiographic results of consecutive ceramic-on-ceramic bearings with and without a metal-backed titanium sleeve in patients undergoing total hip arthroplasty.

METHODS

Eighty-five patients (64 women and 21 men; average age 55.2 years) were included in the A group without sleeve while 147 patients (116 women and 31 men; average age 54.2 years) were included in the B group with sleeve. Clinical and radiologic measurements at follow-up (range, 5-14 years; average, 8.1 years) were analyzed.

RESULTS

The mean latest postoperative Harris Hip Score was 89.1 for patients from both groups. One joint (1.2%) in the A group displayed ceramic liner fracture, while no incidences of liner fracture occurred in the B group. Audible squeaking was observed in 1 joint (1.2%) in the A group and 1 (0.7%) in the B group. The mean annual liner rate of wear was 0.0049 and 0.0046 mm/y for the A group and B group, respectively. Three joints in the A group (3.5%) required revision total hip arthroplasty because of individual episodes of aseptic cup loosening, ceramic liner fracture, and infection. One joint in the B group (0.7%) required revision because of progressive osteolysis of the proximal femur. Ten-year Kaplan-Meier survivorship, based on an end point of component loosening and bearing failure, was 97.6% for the A group and 99.3% for the B group.

CONCLUSION

There were no clinical, radiographic, or survivorship differences between groups.

Metal on Metal or Ceramic on Ceramic for Cementless Total Hip Arthroplasty: A Meta-Analysis

BACKGROUND

Hard bearings, metal on metal (MOM) and ceramic on ceramic (COC), have been developed to overcome polyethylene wear-related osteolysis, but comparisons between these 2 hard bearings are limited. We performed a meta-analysis to determine revision rates for (1) any reason, (2) aseptic loosening, (3) periprosthetic joint infection (PJI), and (4) recurrent dislocation between MOM and COC bearings in cementless total hip arthroplasty.

METHODS

This analysis included 3 studies comparing COC and MOM bearings and 56 studies reporting outcomes of MOM or COC bearings. We conducted a comparison meta-analysis (with a fixed-effects model) on the 3 comparative studies and a proportional meta-analysis on the data from the 59 articles to determine a consensus.

RESULTS

In the comparison meta-analysis, MOM showed higher revision rate than COC for any reason (odds ratio = 2.39, P = .046) and PJI (odds ratio = 6.21, P = .015). In the proportion meta-analysis, the MOM group showed significantly higher revision rate than COC group for any reason, aseptic loosening, and PJI.

CONCLUSION

MOM bearings were associated with a higher risk of revision for any reason and PJI than COC bearings after cementless total hip arthroplasty.

Comparative Results From a National Joint Registry Hip Data Set of a New Cross-Linked Annealed Polyethylene vs Both Conventional Polyethylene and Ceramic Bearings

BACKGROUND

Major concerns in hip arthroplasty concern the fate of bearing surfaces. Highly cross-linked polyethylene materials (HXLPE) currently demonstrate successful in vitro results with new technical procedures of cross-linking the polyethylene material, whereas processing the polyethylene below its melting temperature to produce so-called "annealed HXLPE" would allow retention of important mechanical properties.

METHODS

Data released by the National Joint Registry of England and Wales addressing in 45,877 hips the same Trident uncemented cup, allowed us to compare the performance of a consecutive cohort of patients implanted with the newest generation of annealed HXLPE acetabular bearings (X3: 21,470) vs 2 consecutive nonselected cohorts, one with conventional polyethylene (N2vac: 8225) and one with ceramic-on-ceramic (CoC) hip bearings (AL: 16,182). The main end point in survivorship has been first defined as revision for any cause, then for any cause which could be related to a failure of the bearing couple.

RESULTS

At 6-year follow-up, all Trident cups demonstrated encouraging global survival cumulative rates all between 95% and 99%. A first study demonstrated better survivorship with X3-HXLPE liners vs conventional ultrahigh molecular weight polyethylene. On the second parallel study, the cumulative survival rates were better for X3 liners as compared to CoC bearings. Moreover, when ranking the yearly cumulative percent revision rates, again the best results were obtained with X3 liners with small alumina heads (cumulative percent revision rate at 0.298).

CONCLUSION

Within the frame of this Trident study, the use of this X3 highly cross-linked annealed polyethylene could be considered as a reliable alternate solution to CoC bearings.

Significantly Lower Wear of Ceramic-on-Ceramic Bearings Than Metal-on-Highly Cross-Linked Polyethylene Bearings: A 10- to 14-Year Follow-Up Study

BACKGROUND

This study aimed to retrospectively compare clinical and radiographic results between consecutive total hip arthroplasties (THAs) using ceramic on ceramic (CoC) and metal-on-highly cross-linked polyethylene (MoP), with >10 years of follow-up.

METHODS

Sixty-seven patients (52 women and 15 men) underwent CoC THA, whereas 81 (67 women and 14 men) underwent MoP THA. The average patient age at the time of surgery was 54.0 years in the CoC group and 54.2 years in the MoP group.

RESULTS

The mean postoperative Harris Hip Scores were 88.9 and 86.4 in the CoC and MoP groups, respectively (P = .063), and the mean annual liner rates of wear were 0.0043 and 0.0163 mm/year, respectively (P < .001). Osteolysis was observed on the femoral side of 1 joint (1.5%) in the CoC group and in 1 (1.2%) acetabular and femoral (1.2%) joint each in the MoP group. Three joints (3.7%) in the MoP group showed aseptic cup loosening, one of which (1.2%) required revision THA because of progression of the loosening. Revision THA was also required in 1 joint (1.5%) in the CoC group because of ceramic fracture. The Kaplan-Meier survival rate at 10 years with implant loosening or revision THA as the end point was 98.5% for CoC and 96.3% for MoP (P = .416).

CONCLUSION

The wear rate of CoC implants was significantly lower than that of MoP implants. Kaplan-Meier survival at 10 years with implant loosening and revision THA as end points did not differ significantly between these implants.

A Randomized Trial Comparing Ceramic-on-Ceramic Bearing vs Ceramic-on-Crossfire-Polyethylene Bearing Surfaces in Total Hip Arthroplasty

BACKGROUND

Bearing surfaces in total hip arthroplasty (THA) may affect implant longevity and hence patient outcomes. This randomized clinical trial determined how ceramic-on-ceramic (CERAMIC) bearing THA affected joint-specific pain, function, and stiffness and prosthesis fixation/longevity over 10 postoperative years compared with ceramic-on-highly-crosslinked-polyethylene (POLYETHYLENE) bearing THA. This is a follow-up to previously reported 5-year outcomes.

METHODS

Subjects aged <61 years were randomized to CERAMIC (n = 48) or POLYETHYLENE (n = 44) THA. Subjects were assessed using the Western Ontario McMaster Osteoarthritis Index and the RAND 12-Item Health Survey preoperatively, and at 1, 5, and 10 years postoperatively. Plain radiographs were evaluated at 10 years for fixation, and medical records were reviewed for revisions.

RESULTS

Of 92 subjects, 6 (7%) died within 10 years; 68 (79%) survivors provided radiographic and/or clinical follow-up at 10 years postoperatively. Improvements seen at 5 years in both the Western Ontario McMaster Osteoarthritis Index and RAND 12-Item Health Survey were retained at 10 years with no group differences (P > .48). There were no failures or loss of fixation related to bearing surfaces/wear in either group. Over 10 years, 3 subjects in the POLYETHYLENE group had revisions that were related to recurrent dislocation; 2 revisions were performed within 2 years of surgery, and one further subject underwent revision at 7 years postoperatively.

CONCLUSIONS

This is one of the first randomized clinical trials to examine 10-year outcomes between CERAMIC and POLYETHYLENE bearing THAs. Both bearing surfaces performed well out to 10 years in subjects who were <61 years at time of surgery.

Is there any difference in survivorship of total hip arthroplasty with different bearing surfaces? A systematic review and network meta-analysis

PURPOSE

Although many total hip bearing implants are widely used all over the world, simultaneous comparisons across the numerous available bearing surfaces are rare. The purpose of this study was to compare the survivorship of total hip arthroplasty (THA) with six available bearing implants.

METHODS

We conducted a systematic review of randomized controlled trials (RCTs) reporting survivorship or revision of ceramic-on-ceramic (CoC), ceramic-on-conventional polyethylene (CoPc), ceramic-on-highly-crosslinked polyethylene (CoPxl), metal-on-conventional polyethylene (MoPc), metal-on-highly-crosslinked polyethylene (MoPxl), or metal-on-metal (MoM) bearing implants. The synthesis of present evidence was performed by both the traditional direct-comparison meta-analysis and network meta-analysis.

RESULTS

In total, 40 RCTs involving a total of 5321 THAs were identified. The pooled data of network meta-analysis showed no difference in relative risk (RR) of revision across CoC, CoPc, CoPxl and MoPxl bearings. However, the MoM bearing was demonstrated with a significant higher risk of revision compared with CoC (RR 5.10; 95% CI=1.62 to 16.81), CoPc (RR 4.80; 95% CI=1.29 to 17.09), or MoPxl (RR 3.85; 95% CI=1.16 to 14.29), and the MoPc bearing was indicated with a higher risk of revision compared with CoC (RR 2.83; 95% CI=1.20 to 6.63). The ranking probabilities of the effective interventions also revealed the inferiority of the MoM and MoPc implants in survivorship (both 0%, 95% CI=0% to 0%) compared with CoC (39%, 95% CI=0% to 100%), CoPc (33%, 95% CI=0% to 100%), CoPxl (7%, 95% CI=0% to 100%) or MoPxl (21%, 95% CI=0% to 100%).

CONCLUSIONS

The present evidence indicated the similar performance in survivorship among CoC, CoPc, CoPxl and MoPxl bearing implants, and that all likely have superiority compared with the MoM and MoPc bearing implants in THA procedures. Long-term RCT data are required to confirm these conclusions and better inform clinical decisions.

The Survival Analysis in Third-Generation Ceramic-On-Ceramic Total Hip Arthroplasty

A total of 527 patients (577 hips) who underwent primary THA using third-generation ceramic-on-ceramic (CoC) articulation were retrospectively reviewed. They were followed up for an average of 5.9 years. Seven hips experienced liner fracture and 14 hips experienced head fracture. Squeaking occurred in eight hips. The revision rate in this study was 5.2%, but excluding the cases of ceramic head and liner fracture, there were nine cases (1.6%) of revision surgery. Considering revision for any reason as the end point, mean survivorship was 93% at 10 years. According to the femoral head size and neck length, 28 mm head with short neck has the worst survivorship of 89% at 10 years. Overall, our study showed a higher rate of ceramic fracture compared with other studies.

There Are No Differences in Short- to Mid-term Survivorship Among Total Hip-bearing Surface Options: A Network Meta-analysis

BACKGROUND

Total hip arthroplasty (THA) is increasingly being performed in patients with long life expectancies and active lifestyles. Newer implant bearing surfaces, with superior wear characteristics, often are used in this cohort with the goal of improving longevity of the prosthesis, but comparisons across the numerous available bearing surfaces are limited, so the surgeon and patient may have difficulty deciding which implants to use.

QUESTIONS/PURPOSES

The purpose of this study was to answer the following question: Is there a short- to mid-term survivorship difference between common THA bearings used in patients younger than age 65 years?

METHODS

We conducted a systematic review to identify randomized clinical trials (RCTs) published after 2000 that reported survivorship of ceramic-on-ceramic (CoC), ceramic-on-highly crosslinked polyethylene (CoPxl), or metal-on-highly crosslinked polyethylene (MoPxl) bearings. To qualify for our review, RCTs had to have a minimum 2-year followup and study patients were required to have an average age younger than 65 years. Direct-comparison meta-analysis and network meta-analysis were performed to combine direct and indirect evidence.

RESULTS

Direct-comparison meta-analysis found no differences among the bearing surfaces in terms of the risk of revision; this approach demonstrated a risk ratio for revision of 0.65 (95% confidence interval [CI], 0.19-2.23; p = 0.50) between CoC and CoPxl and a risk ratio for revision of 0.40 (95% CI, 0.06-2.63; p = 0.34) between CoC and MoPxl. Network meta-analysis (with post hoc modification) likewise found no differences in survivorship across the three implant types, demonstrating the following probabilities of most effective implant with 95% credible intervals (CrI): CoC = 64.6% (0%-100%); CoPxl = 24.9% (0%-100%); and MoPxl = 9.9% (0%-100%). The CrIs ranged from 0% to 100% for all three bearing surfaces. Direct-comparison meta-analysis allowed for pooling of five RCTs, including 779 THAs, whereas network meta-analysis (before post hoc analysis) enabled pooling of 18 RCTs, including 2599 THAs.

CONCLUSIONS

Current published evidence does not support survivorship differences among commonly used bearing surfaces in patients younger than age 65 years undergoing THA at short- to mid-term followup. Long-term RCT data will be needed to determine if a survivorship benefit is realized in younger, more active patients over time.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Comparison of ceramic-on-ceramic to metal-on-polyethylene bearing surfaces in total hip arthroplasty: a meta-analysis of randomized controlled trials

Background

In recent years, the choice of ceramic-on-ceramic (COC) and metal-on-polyethylene (MOP) in primary total hip arthroplasty (THA) remains controversial. The purpose of this study was to compare the reliability and durability of COC with that of MOP bearing surfaces in THA.

Methods

Based on prospective randomized controlled trials (RCTs) searched from Pubmed, Embase, Web of Science, and Cochrane central database, we performed a meta-analysis for comparing clinical and radiographic outcomes of COC with those of MOP. Two investigators independently selected studies, extracted data, and assessed risk of bias. Relative risks and weighted mean differences from each trial were pooled using random-effect or fixed-effect models depending on the heterogeneity of the included studies.

Results

Five RCTs involving 897 patients with 974 hips met predetermined inclusion criteria. Our results demonstrated COC significantly decreased the risks of revision, osteolysis and radiolucent line, aseptic loosening, and dislocation and increased the risks of squeaking and intraoperative implant fracture compared with MOP. There was no significant difference between the two groups in postoperative hip function, deep infection, and heterotopic ossification.

Conclusions

Generally, despite more squeaking and intraoperative implant fracture, our findings support the use of COC bearing surface which has lower rates of revision, osteolysis and radiolucent line, aseptic loosening, and dislocation compared with MOP.

Squeaking in large diameter ceramic-on-ceramic bearings in total hip arthroplasty

We analyzed the results of 206 consecutive total hip arthroplasties performed using large diameter ceramic-on-ceramic bearings. At an average follow-up of 28months, the mean Harris Hip Score improved from 54 to 92. Fifteen (7.3%) hips were noted to squeak. There was no significant difference between silent and squeaking hips with regards to age, weight, height, BMI, range of movement, femoral head diameter, leg length, and offset or center of rotation. No correlation was present between incidence of squeaking and increasing cup inclination and anteversion. 5.2% of cups orientated within Lewinnek's safe zone squeaked. No hips required revision for squeaking. While large diameter ceramic bearings may produce squeaking, our early results of surgery using large head ceramic bearings are encouraging. However, long-term follow-up is required.

Comparative effectiveness of ceramic-on-ceramic implants in stemmed hip replacement: a multinational study of six national and regional registries

BACKGROUND

The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration).

METHODS

A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE.

RESULTS

A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term.

CONCLUSIONS

Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery.

Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years

PURPOSE

To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses.

METHODS

Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability).

RESULTS

The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation.

CONCLUSION

Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

Total hip replacement for the treatment of end stage arthritis of the hip: a systematic review and meta-analysis

Background

Evolvements in the design, fixation methods, size, and bearing surface of implants for total hip replacement (THR) have led to a variety of options for healthcare professionals to consider. The need to determine the most optimal combinations of THR implant is warranted. This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip.

Methods

A comprehensive literature search was undertaken in major health databases. Randomised controlled trials (RCTs) and systematic reviews published from 2008 onwards comparing different types of primary THR in patients with end stage arthritis of the hip were included.

Results

Fourteen RCTs and five systematic reviews were included. Patients experienced significant post-THR improvements in Harris Hip scores, but this did not differ between impact types. There was a reduced risk of implant dislocation after receiving a larger femoral head size (36 mm vs. 28 mm; RR = 0.17, 95% CI: 0.04, 0.78) or cemented cup (vs. cementless cup; pooled odds ratio: 0.34, 95% CI: 0.13, 0.89). Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision. There was no impact of femoral stem fixation and cup shell design on implant survival rates. Evidence on mortality and complications (aseptic loosening, femoral fracture) was inconclusive.

Conclusions

The majority of evidence was inconclusive due to poor reporting, missing data, or uncertainty in treatment estimates. The findings warrant cautious interpretation given the risk of bias (blinding, attrition), methodological limitations (small sample size, low event counts, short follow-up), and poor reporting. Long-term pragmatic RCTs are needed to allow for more definitive conclusions. Authors are encouraged to specify the minimal clinically important difference and power calculation for their primary outcome(s) as well CONSORT, PRISMA and STROBE guidelines to ensure better reporting and more reliable production and assessment of evidence.

Hip resurfacing versus total hip arthroplasty: a systematic review comparing standardized outcomes

BACKGROUND

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

QUESTIONS/PURPOSES

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

METHODS

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

RESULTS

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95-3.1) versus 7.8 for THA (95% CI, 7.2-8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1-11.3) versus 7.1 (95% CI, 6.7-7.6; p = 0.068), and 7.9 (95% CI, 5.4-11.3) versus 1.8 (95% CI, 1.3-2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2-4.6) versus 0.9 (95% CI, 0.6-1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

CONCLUSIONS

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.

No differences found in bearing related hip survivorship at 10-12 years follow-up between patients with ceramic on highly cross-linked polyethylene bearings compared to patients with ceramic on ceramic bearings

At a minimum follow-up of ten years we compared clinical and radiographic findings and survivorship in a cohort of 412 patients (447 hips) who received alumina on alumina CoC bearings to findings from a cohort of 216 patients (228 hips) with alumina on highly cross-linked polyethylene (HXLPE) bearings. All patients were operated for osteoarthritis. With bearing-related complications as endpoint, analysis showed no significant difference in survivorship between cohorts (99.8% for the CoC vs. 99.4% for HXLPE). In addition, there were no significant differences in clinical and radiographic findings between cohorts. We concluded that alumina on HXLPE bearings are a reasonable lower cost alternative to ceramic on ceramic bearing couples.

Nine year follow-up of a ceramic-on-ceramic bearing total hip arthroplasty utilizing a layered monoblock acetabular component

INTRODUCTION

Early ceramic bearing systems in total hip arthoplasty (THA) sought to provide long term wear improvement over traditional metal on polyethylene systems. However, previous designs exhibited fractures of the ceramic acetabular liner, leading to the development of the Implex Hedrocel ceramic bearing THA system where the ceramic liner was supported on a layer of polyethylene intended to transition liner loads to the metal shell, a so-called "sandwich" design. Unfortunately, the device trial was stopped to further enrollment when liner fractures were reported. The current study examines nearly 10-year follow-up on 28 devices implanted by two surgeons at one institution in order to document ceramic bearing system performance over a longer time period.

METHODS

Radiographic and patient reported outcomes, in the form of Harris Hip Scores (HHS) and 12-Item Short Form Health Survey (sF-12), were collected.

RESULTS

During the study period two cups were replaced, one at three years and a second at seven years. At the five year follow-up HHS were similar to those reported in the literature for devices with traditional metal-on-polyethylene bearing surfaces and for other sandwich ceramic bearing designs. At the nine year follow-up, the HHS had not changed significantly and SF-12 scores measuring overall physical and mental health were higher than age matched national norms (p<0.001). There were no signs of cup migration, stem subsidence, osteolysis or cup loosening at any time up to the last follow-up in this patient cohort. The 89% survivorship rate and device revisions due to delamination of the liner observed in this group were similar to those reported earlier for this device and for other "sandwich design" ceramic bearing systems.

DISCUSSION

This cohort did not exhibit new failure modes and HHS and SF-12 scores indicated high functionality for the majority of patients. These data suggest that a focus on preventing ceramic liner fracture through design and/or materials improvements may result in a device with long-term functionality.

A randomised prospective evaluation of ceramic-on-ceramic and ceramic-on-highly cross-linked polyethylene bearings in the same patients with primary cementless total hip arthroplasty

PURPOSE

Very few studies have compared alumina-on-alumina ceramic and alumina-on-highly cross-linked polyethylene bearings in the same patient. The purpose of this prospective randomised study was to compare the clinical and radiographic results and the prevalence of osteolysis in cementless total hip arthroplasty using an alumina-on-alumina and alumina-on-highly cross-linked polyethylene bearings in young active patients.

METHODS

We prospectively compared the results of 100 patients (200 hips) who had undergone a cementless total hip arthroplasty with an alumina-on-alumina ceramic bearing in one hip and an alumina-on-highly cross-linked polyethylene in the other. There were 66 men and 34 women with a mean age of 45.3 years (range, 21-49 years) at the time of surgery. The mean follow-up was 12.4 years (range, 11-13 years). The patients were assessed clinically and radiographically at three months, one year, and annually thereafter.

RESULTS

Harris hip, Western Ontario and McMaster Universities Osteoarthritis Index, and University of California, Los Angeles activity scores did not show statistically significant differences between the two groups of bearings preoperatively or at the time of final follow-up. Radiographic findings of the component were not significantly different between the two groups. The mean polyethylene linear penetration was 0.031 ± 0.004 mm per year. No hips in either group displayed osteolysis. The Kaplan-Meier survivorship with revision as the end point at 12.4 years was 100% (95% confidence interval [CI], 94-100%) for the femoral component in both groups and 99% (95%CI, 93-100%) for the acetabular component.

CONCLUSION

The clinical and radiographic results of using an alumina-on-alumina ceramic and alumina-on-highly cross-linked polyethylene bearings were similar.

Survivorship, patient reported outcome and satisfaction following resurfacing and total hip arthroplasty

Resurfacing (RA) and total hip arthroplasty (THA) are options in the treatment of debilitating hip pathology. 381 patients that had undergone arthroplasty with a BHR RA, ASR RA, metal-on-metal (MoM) THA or ceramic-on-ceramic (CoC) THA were reviewed for satisfaction, function, health and survivorship at a median follow up of 50 months. Significantly lower survivorship for revision and reoperation was observed in the ASR group. The BHR and CoC demonstrated better outcome scores than the ASR (OHS and SAPS) and the BHR better scores than the MoM (OHS and SF12 PCS). In the short to medium term, survivorship and outcomes for the best performing RA (BHR) and THA (CoC) were comparable. There was a non-significant trend towards poorer outcome scores in the MoM THA group.

Ceramic-on-ceramic bearings in hip arthroplasty: state of the art and the future

This systematic review of the literature summarises the clinical experience with ceramic-on-ceramic hip bearings over the past 40 years and discusses the concerns that exist in relation to the bearing combination. Loosening, fracture, liner chipping on insertion, liner canting and dissociation, edge-loading and squeaking have all been reported, and the relationship between these issues and implant design and surgical technique is investigated. New design concepts are introduced and analysed with respect to previous clinical experience.

Orthopedic applications of silicon nitride ceramics

Silicon nitride (Si(3)N(4)) is a ceramic material developed for industrial applications that demand high strength and fracture resistance under extreme operating conditions. Recently, Si(3)N(4) has been used as an orthopedic biomaterial, to promote bone fusion in spinal surgery and to develop bearings that can improve the wear and longevity of prosthetic hip and knee joints. Si(3)N(4) has been implanted in human patients for over 3 years now, and clinical trials with Si(3)N(4) femoral heads in prosthetic hip replacement are contemplated. This review will provide background information and data relating to Si(3)N(4) ceramics that will be of interest to engineering and medical professionals.

Comparative assessment of implantable hip devices with different bearing surfaces: systematic appraisal of evidence

OBJECTIVE

To determine comparative safety and effectiveness of combinations of bearing surfaces of hip implants.

DESIGN

Systematic review of clinical trials, observational studies, and registries.

DATA SOURCES

Medline, Embase, Cochrane Controlled Trials Register, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the United States Food and Drug Administration.

STUDY SELECTION

Criteria for inclusion were comparative studies in adults reporting information for various combinations of bearings (such as metal on metal and ceramic on ceramic). Data search, abstraction, and analyses were independently performed and confirmed by at least two authors. Qualitative data syntheses were performed.

RESULTS

There were 3139 patients and 3404 hips enrolled in 18 comparative studies and over 830 000 operations in national registries. The mean age range in the trials was 42-71, and 26-88% were women. Disease specific functional outcomes and general quality of life scores were no different or they favoured patients receiving metal on polyethylene rather than metal on metal in the trials. While one clinical study reported fewer dislocations associated with metal on metal implants, in the three largest national registries there was evidence of higher rates of implant revision associated with metal on metal implants compared with metal on polyethylene. One trial reported fewer revisions with ceramic on ceramic compared with metal on polyethylene implants, but data from national registries did not support this finding.

CONCLUSIONS

There is limited evidence regarding comparative effectiveness of various hip implant bearings. Results do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional metal on polyethylene or ceramic on polyethylene bearings.

State of the art in hard-on-hard bearings: how did we get here and what have we achieved?

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Survival of hard-on-hard bearings in total hip arthroplasty: a systematic review

BACKGROUND

Improvements in prosthetic materials, designs, and implant fixation for THA have led to bearing surface wear being the limitation of this technology. Hard-on-hard bearings promise decreased wear rates and increased survival. However, there may be different survival rates based on bearing materials, manufacturing technologies, and femoral component designs. Additionally, survival rate variability may be based on study design.

QUESTIONS/PURPOSES

We determined survival rates and study levels of evidence and quality for the following bearings: stemmed metal-on-metal THA, metal-on-metal hip resurfacing, ceramic-on-ceramic THA, and ceramic-on-metal THA.

METHODS

We performed a systematic review of the peer-reviewed literature addressing THA hard-on-hard bearings. Quality for Level I and II studies was assessed.

RESULTS

The four Level I or II second-generation stemmed metal-on-metal THA studies reported between 96% and 100% mean survival at 38 to 60 months. The two Level I hip resurfacing studies reported 94% and 98% mean survival at 56 and 33 months. The four Level I studies of ceramic-on-ceramic THA reported survival from 100% at mean 51 months to 96% at 8 years.

CONCLUSIONS

While hard-on-hard bearing survival rates have generally been variable with earlier designs, contemporary implants have demonstrated survival of 95% or greater at followup of between 3 and 10 years. Some variability in survival may be due to differences in surgical technique, component positioning, and implant designs. As bearing designs continue to improve with modified materials and manufacturing techniques, use will increase, especially in young and active patients, though concerns remain about the increased reports of adverse events after metal-on-metal bearings.

Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty

Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings.

Nine years follow-up of 100 ceramic-on-ceramic total hip arthroplasty

The aim of this study was to evaluate the first 100 cementless ceramic-on-ceramic total hip arthroplasty (THA) performed at our institution with more than nine years of follow-up. Clinical evaluation was performed using Harris hip score. Radiological evaluation was performed by two surgeons. Four patients were lost to follow-up. Harris hip score significantly improved at latest follow-up. Radiological analysis showed calcar osteolysis for 75 patients and one cup loosening. One patient required a revision five years postoperatively for cup loosening. Based on these results and the routine use of a navigation system to optimise positioning of the implants, we advocate the use of uncemented hydroxyapatite coated ceramic-on-ceramic THA in young and active patients in our current practice.

Excellent results with cementless total hip arthroplasty and alumina-on-alumina pairing: minimum ten-year follow-up

Ceramic-on-ceramic coupling is thought to be a durable alternative to metal- or alumina-on-polyethylene pairing. No evidence exists suggesting superior clinical and radiological results for hydroxyapatite-coated stems versus uncoated stems. The aim of this study is to report the performance of an alumina-on-alumina bearing cementless total hip arthroplasty and to compare stems with a tapered design with and without hydroxyapatite coating. We prospectively analysed the results of cementless tapered femoral stems (40 hydroxyapatite-coated versus 22 uncoated stems), a metal-backed fibre mesh hydroxyapatite-coated socket and alumina-on-alumina pairing. Of 75 hips studied, 62 were available for follow-up (mean of 10.5 years after surgery). The average Harris hip score was 90. Only one hydroxyapatite-coated stem was revised for aseptic loosening. One instance of non-progressive osteolysis was detected around a screw of a cup. All other components showed radiographic signs of stable ingrowth. Hydroxyapatite coating of the stem had no significant impact on the clinical or radiological results. Total hip arthroplasty with the presented implant and pairing provides a durable standard for all patients requiring hip joint replacement against which all newer generations of cementless implants should be judged.