Are Ceramic Bearings Becoming Cost-Effective for All Patients?

Lower Rates of Ceramic Femoral Head Use in Non-White Patients in the United States, a National Registry Study

BACKGROUND

The purpose of our study was to investigate the association of race and ethnicity with the use of the newest technology and postoperative outcomes in total hip arthroplasty (THA) using the American Academy of Orthopaedic Surgeons (AAOS) American Joint Replacement Registry (AJRR).

METHODS

Adult THA procedures were queried from the AJRR from 2012 to 2020. A mixed-effects multivariate regression model was used to evaluate the association of race and ethnicity with the use of the newest technology (ceramic femoral head, dual-mobility implant, and robotic assist) at 30-day, and 90-day readmission. A proportional subdistribution hazard model was used to model a risk of revision THA.

RESULTS

There were 85,188 THAs with complete data for an analysis of outcomes and 103,218 for an analysis of ceramic head usage. The median length of follow-up was 37.9 months (interquartile range [IQR] 21.6 to 56.3 months). In multivariate models, compared to White non-Hispanic patients, Black (odds ratio [OR] 0.79, 95% confidence interval [CI] 0.69-0.92, P < .001), Hispanic (OR 0.76, CI 0.59-0.99, P = .037), Asian (OR 0.74, CI 0.55-1.00, P = .045), and Native American (OR 0.52, CI 0.30-0.87, P = .004) patients all had significantly lower rates of ceramic head use in THA. Compared to White non-Hispanic patients, Asian (hazard ratio [HR] 0.39, CI 0.18-0.86, P = .008) and Hispanic (HR 0.43, CI 0.19-0.98, P = .043) patients had significantly lower rates of revision. No differences in 30-day or 90-day readmission rates were seen.

CONCLUSION

Black, Hispanic, Native American, and Asian patients had lower rates of ceramic head use in THA when compared to White patients. These differences did not translate into worse clinical outcomes on a short-term follow-up. In fact, Asian patients had lower revision rates compared to non-Hispanic White patients. Additional study is necessary to evaluate the long-term consequence of lower ceramic head use in non-White patients in the United States.

Hospital Costs for Unsuccessful Two-Stage Revisions for Periprosthetic Joint Infection

BACKGROUND

Although 2-stage exchange arthroplasty is the preferred surgical treatment for periprosthetic joint infection (PJI) in the United States, little is known about the risk of complications between stages, mortality, and the economic burden of unsuccessful 2-stage procedures.

METHODS

The 2015-2019 Medicare 100% inpatient sample was used to identify 2-stage PJI revisions in total hip and knee arthroplasty patients using procedural codes. We used the Fine and Gray sub-distribution adaptation of the conventional Kaplan-Meier method to estimate the probability of completing the second stage of the 2-stage PJI infection treatment, accounting for death as a competing risk. Hospital costs were estimated from the hospital charges using "cost-to-charge" ratios from Centers for Medicare and Medicaid Services.

RESULTS

A total of 5094 total hip arthroplasty and 13,062 total knee arthroplasty patients had an index revision for PJI during the study period. In the first 12 months following the first-stage explantation, the likelihood of completing a second-stage PJI revision was 43.1% (95% confidence interval [CI] 41.7-44.5) for hips and 47.9% (95% CI 47.0-48.8) for knees. Following explantation, 1-year patient survival rates for hip and knee patients were 87.4% (95% CI 85.8-88.9) and 91.4% (95% CI 90.6-92.2), respectively. The median additional cost for hospitalizations between stages was $23,582 and $20,965 per patient for hips and knees, respectively. Hospital volume, Northeast or Midwest region, and younger age were associated with reduced PJI costs (P < .05).

CONCLUSION

Although viewed as the most preferred, the 2-stage revision strategy for PJI had less than a 50% chance of successful completion within the first year, and was associated with high mortality rates and substantial costs for treatment failure.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Delta-on-Delta Ceramic Bearing Surfaces in Revision Hip Arthroplasty

BACKGROUND

Fourth-generation ceramic-on-ceramic couplings were developed to improve ceramic toughness and strength. Encouraging outcomes in primary total hip arthroplasty were reported. This coupling was proposed as an attractive option even in the case of revision procedures, particularly in younger patients with a longer life expectancy. However, the pertinent literature is scarce. Thus, a registry study was conducted to investigate the midterm survival rates and reasons for re-revision of the fourth-generation ceramic-on-ceramic bearing surfaces in revision hip arthroplasties.

METHODS

A total of 327 revision implants (all the components were exchanged) with BIOLOX Delta couplings were investigated using the regional orthopedic registry RIPO. The demographics, the survival rates, and the reasons for re-revision were assessed. Revisions with bearings other than Delta were compared.

RESULTS

Delta bearings achieved a survival rate of 90.5% at 7 years, with stable results. Twenty-six (8%) re-revisions occurred at a mean follow-up of 4.1 years. And 2.8% of the re-revisions were due to recurrent dislocations; 1.5% of the cases were due to cup aseptic loosening. Septic loosening occurred in 1.6% of the cases. No ceramic fractures were reported. When compared to revisions with bearings other than Delta-on-Delta, Delta coupling cohort achieved similar performances at 5 and 7 years. Lower, nonsignificant rates of aseptic and septic loosening were reported in Delta cohort.

CONCLUSION

Delta-on-Delta couplings demonstrated to be reliable bearing surfaces in revision settings at a midterm follow-up. Clinical studies and longer follow-ups are required to investigate potential adverse effects, like squeaking and fractures, and confirm these preliminary findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Are Ceramic Bearings Becoming Cost-Effective for All Patients Within a 90-Day Bundled Payment Period?

BACKGROUND

We analyzed whether the total hospital cost in a 90-day bundled payment period for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) total hip arthroplasty (THA) bearings was changing over time, and whether the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of US$325.

METHODS

A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The total inpatient cost, calculated up to 90 days after index discharge, was computed using cost-to-charge ratios, and hospital payment was analyzed. The differential total inpatient cost of C-PE and COC bearings, compared to metal-on-polyethylene (M-PE), was evaluated using parametric and nonparametric models.

RESULTS

After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost up to 90 days for primary THA with C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (P < .001). From the nonparametric analysis, the median total hospital cost was US$296-US$353 more for C-PE and COC than M-PE. Cost differentials were found to decrease significantly over time (P < .001).

CONCLUSION

Patient and clinical factors had a far greater impact on the total cost of inpatient THA surgery than bearing selection, even when including readmission costs up to 90 days after discharge. Our findings indicate that the cost-effectiveness thresholds for ceramic bearings relative to M-PE are changing over time and increasingly achievable for the Medicare population.