As this study offers the longest follow-up for a single APT component in RA, it provides greater insight into long-term survival rates of APT TKA. The study shows good long-term survival, and revision rates are comparable with TKA revision rates as noted in several national joint registries [
]. Previous reports of APT TKA in RA patients show results comparable with our study. Kristensen and Laskin showed survival rates ranging from 81% to 89% at the ten year follow-up [
]. Rodriquez reported a 91% survival rate at 15 years, with endpoint as revision for any reason [
Our study has some limitations: First, some patients were lost to follow-up. To account for these patients, we included a worst-case scenario to give an absolute lower limit of the revision rate. The worst-case scenario assumes all patients lost to follow-up were revised. The revision rate of the worst-case scenario lies in the range of revision rates according several national joint registries, as illustrated in Fig.
]. Despite thorough attempts to collect complete follow-up of all patients, revision in some patients could not be ruled out with absolute certainty. The most important reason for this lack of information was the limited storage time of medical files, which are destroyed ten years after the patient has died. Consequently, medical information for patients who died more than ten years prior to our study was almost impossible to trace. We checked the community registry to determine the end of study time of each patient and found that many patients died during the follow-up. At the time of analysis, information of the patients who died not long after TKA could therefore not be retrieved. Of these patients, we ruled out revision in our hospital and in the two nearest hospitals by gathering information from their databases. Additionally, that group was comparable with the complete follow-up group regarding several patient demographics, as seen in Table
. A second limitation was that the APT total condylar knee prosthesis used in this study is no longer used in today’s orthopaedic practice. As the modern polyethylene types are expected to be superior to the APT in our study, the revision rate of a modern APT may even be lower than the revision rate of the total condylar knee prosthesis, which had an excellent long-term track record [
RA is a chronic inflammatory disease that leads to varying degrees of functional impairment and disability [
]. Many RA patients still require total joint arthroplasty despite improvements in pharmacological treatment [
]. Functional status after TKA is inferior to that of OA patients treated with TKA [
]. A reason is the polyarticular involvement and the declining functional status due to the disease. In the literature, patients who are relatively sedentary and less active are classified as low demand, are frequently elderly (>70–75 years old) or have RA [
]. Low-demand patients generally place lower stress on their TKA and thus reduce the wear rate and risk of revision. According to the literature, APT TKA can be an acceptable treatment for such low-demand patients and a cost-saving treatment option [
]. Many studies have compared APT with MBT TKA. These studies investigated possible superiority of MBT components. None of these studies showed significant differences in favour of MBT TKA [
]. In addition, a meta-analysis favours the use of a nonstabilised APT component over an MBT component [
]. Although all these studies show good results for APT designs, one study showed high revision rates of one specific APT design with low conformity [
]. This study mainly reviewed OA patients (93%); our study, on the other hand, reviews RA patients. Additionally, the design of this tibial component differs from the APT design of the total condylar prosthesis by conformity of the prosthesis between the femoral and tibial components. The APT design of the total condylar has a higher conformity. In conclusion, our results suggest that APT TKA could be a successful and cost-saving treatment for end-stage knee arthritis in rheumatoid patients.