Cost Analysis of Ceramic Heads in Primary Total Hip Arthroplasty
- Keith J. Carnes, Susan M. Odum, Jennifer L. Troyer, Thomas K. Fehring
- J Bone Joint Surg Am. 2016;98:1794-800. http://dx.doi.org/10.2106/JBJS.15.00831
- Level of Evidence:
- Level III
Carnes et al used a Markov decision model to compare the cost-effectiveness of ceramic (C) with metal (M, CoCr) femoral heads for bearings with Polyethylene (P) liners. In order to determine costeffectiveness patient-level hospitalization costs were obtained from the Premier Research Database. Included in the study were primary THA patients, with bearing types identified by ICD9 codes, in patients older than 45 years (20,398 of 54,662 THAs). Three price scenarios for CoP and MoP articulations were calculated: (1) $325 cost differential, (2) $1,003, and (3) $600; CoP bearings were always assumed to be more expensive.
Based on information from the HealthEast Joint Replacement Registry the 20-year cumulative revision rate of MoP bearings was estimated to be 14.5 revisions per 100 THAs, corresponding to an incremental annual revision rate of 0.724 per 100 THAs. According to data from the National Joint Registry for England, Wales and North Ireland) the revision rate of THAs with CoP bearings is 25–35% less than for MoP bearings. The authors used the midpoint (30%) to calculate the incremental annual revision rate of CoP bearings to be 0.507 per 100 THAs.
The number of revisions that need to be avoided with CoP bearings in order to be more cost effective strongly depends on the age of the patients as well as the cost differential between ceramic and metal femoral heads. E.g. at a cost differential of $1,003 for a ceramic femoral head, 4.5 revisions per 20 years and 100 THAs have to be avoided for a 50 year old patient, while it is 10.5 for a 80 year old patient. The Markov model indicates that CoP bearings at a cost differential of $325 are cost effective for all patients under 85 years, but not for any patient age group at a cost differential of $ 1,003.
The authors conclude that the results presented in their study can be used to guide the decision making of major stakeholders (including patients, surgeons, hospitals, and device manufacturers) regarding the choice of the bearing surface implanted. At a low cost differential CoP bearings are cost-effective for patients < 85 years of age.
- Results only applicable for the US market.
- Based only on implant cost and revision rates; important cost effectiveness metrics like QALY or QoL have not been included.
- The choice to use cost and revision only to characterize performance may lead to an overstatement of the required revision rates for CoP bearings to be cost-effective.
- Information on revision rate was only available at 9 and 17 years.
- Type of ceramic and PE are not specified and may have an effect on cost as well as revision rates
- When CoP bearings are more expensive than MoP bearings, at a cost differential of $325, CoP bearings were cost effective for all patients under the age of 85y.
- At a cost differential of $1,003 CoP bearings were not cost effective for any patient age group.
- At a cost differential of $600 CoP bearings were cost effective for patients under the age of 64y.
This is another study investigating cost effectiveness of CoP bearings in comparison to MoP bearings in the US. In contrast to Wyles et al 2016, who looked at treatment cost for metal work-ups (Monthly CeraNews January 2017) and revisions in patients with ALTR issues, Carnes et al investigate general revisions only, however, with a much more elaborate statistical method.
Generally, there is a clear trend within all health care systems towards more cost-consciousness and therefore the necessity to better understand the cost-effectiveness of an implant system. Further research is needed to clarify the relationship between effectiveness and costs of articulating bearings in THR.