Long-term follow-up of patients treated with pyrocarbon disc implant for thumb carpometacarpal osteoarthritis: the effect of disc position on outcomes measures

Abstract

Pyrocarbon disc interposition arthroplasty is an effective treatment for thumb base osteoarthritis. However, as with all implant techniques, the disc can (sub)luxate over time. The relationship between disc position, the experienced pain, and the necessity for revision surgery is not known. This study evaluated the effect of radiographic pyrocarbon disc position on the Michigan Hand Questionnaire (MHQ) outcome measurement. In addition, the correlation between disc position and other factors, including pain intensity, thumb strength, and occupation, was assessed. In this retrospective study, we included 136 patients (161 thumbs) with a mean follow-up of 6.7 years (range 3.3–11). Radiographs were scored on disc position and classified as ‘well aligned’ (Grade 1) up to ‘luxated’ (Grade 4). A database used for outcome measures included MHQ scores, pain intensity, satisfaction, thumb strength, range of motion, occupation, and hand dominance. In bivariate analyses, we assessed any association between disc position and outcome measurements. Eighty of the 136 implants (59%) were well-positioned (not displaced), 41% were (slightly) displaced (grade 2–3). No relationship existed between the degree of disc displacement and MHQ scores. Manual labor occupation was the only factor that correlated with more severe disc displacement. We could not detect any association between disc position and other outcome variables including pain intensity, thumb strength, or hand dominance. In conclusion, our study suggests that radiographic disc displacement has little clinical consequences. Future studies must assess if there is a causality between heavy mechanical stress to the CMC1 joint and luxation of the pyrocarbon disc over time.

Level of evidence: IV Therapeutic—Retrospective case series.

Keywords:

• Carpometacarpal joint
• osteoarthritis
• thumb
• surgical procedures
• pyrolytic carbon
• hemiarthroplasty
• radiography

Disclosure statement

All authors (JO, CL, MH, AS, HC, and BH) certify that besides the received research grant they have no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.

Author contributions

JO: conceptualization, methodology, formal analysis, investigation, writing original draft, and project administrating. CvL: conceptualization, formal analysis, investigation, writing original draft, and project administrating. MvH: conceptualization, methodology, formal analysis, and writing original draft. AS: provision of resources, supervision, visualization, review, and editing. JC: methodology, validation, supervision, review, and editing. BvdH: conceptualization, methodology, investigation, provision of resources, supervision, review, and editing.

Ethical approval

The study was approved by the Medical Ethical Review Board Brabant, the Netherlands, no P1704, NL60003.028.16 at 1 May 2017. This study has been performed in accordance with the ethical standards in the 1964 Declaration of Helsinki. This study has been carried out in accordance with relevant regulations of the US Health Insurance Portability and Accountability Act (HIPAA). Written informed consent was obtained from all patients before the study.

Additional information

Funding

The authors received a research grant from Integra Life Sciences. This research grant was used for the execution of the study only and the sponsor was not involved in the collection of the data, analysis of the data, or completion of the manuscript.