The purpose of this study is to describe and to compare the motion analysis parameters, i.e. motion and stability of proximal interphalangeal joints, which were treated with a CapFlex-PIP© implant or silicone implant and to generate basic knowledge about motion analysis of untreated healthy hands.

Inclusion Criteria:

• Patients with proximal interphalangeal joint osteoarthritis in the index or middle finger, treated with a CapFlex-PIP© implant or with a silicone implant and with a follow-up time between 12 and 60 months after primary implantation or
• Patient with one untreated healthy hand without joint osteoarthritis
• Patient aged 50 years and over
• Patient willing and able to give written informed consent to participate in the study

Exclusion Criteria:

• Inflammatory disease (e.g. rheumatoid arthritis)
• Pregnant women
• German language barrier to complete the questionnaires
• Any disease process that would preclude accurate evaluation (e.g. neuromuscular, psychiatric or metabolic disorder)
• Legal incompetence
• Participation in any other medical device or medicinal product study within the previous months that could influence the results of the present study

Patients with proximal interphalangeal joint osteoarthritis in the index or middle finger, treated with a CapFlex-PIP© implant or with a silicone implant and with a follow-up time between 12 and 60 months after primary implantation or patient with one untreated healthy hand without joint osteoarthritis