Purpose: The purpose of our study is to compare hips to knees in regards to the cost per increase in function, to determine the relationship of economic investment to improved quality of life.

Method: During the year 2005, a total of 23 TKA and 41 THA revisions were performed for aseptic mechanical failure. Patients were enrolled prospectively and quality of life questionnaires including the SF-36, WOMAC, Harris Hip Score (HHS), and Knee Society Score (KSS) were collected prior to and following their procedure at two year follow-up. The total cost of the procedure including the hospital, implant, and surgeon fee were implemented in a cost effectiveness model to calculate the mean cost per SF-36, WOMAC, and HHS or KSS point gained. Demographical variables and co-morbidities were collected to determine risk factors for low cost-effectiveness.

Results: The majority of patients had significant improvement in SF-36, WOMAC, HHS and KSS scales. Patients with THA revisions experience a cost per point increase for HHS of $3,000, and $500 per point SF-36 compared to knee patients who experienced a cost per point increase for KSS of $2,000, and $2,800 per point SF-36. The WOMAC exhibited similar cost effectiveness in the subscales of pain, stiffness and functioning.

Conclusion: There are few studies that have compared the cost effectiveness of total joint arthroplasty revision procedures. Given the increasing cost of health care expenditures, prioritization of funding for the different health practices will become necessary. This study demonstrates that revision THA and TKA are relatively cost effective procedures compared to other non-orthopaedic interventions.