 Studies at the shoulder, Achilles tendon and thumb show satisfactory results regarding the use of GaftJacket. Initial trials at the thumb show, that the GraftJacket can be safely and successfully used in TMC OA surgery and therefore represents an acceptable alternative for avoiding possible donor-site morbidity. However, there are no randomised controlled trials RCT in which the outcomes of using a tendon interposition or the GraftJacket are compared. Only with an RCT design it is possible to gain evidence about the advantages of one treatment method over another. The main objective of the study is the comparison between two surgical techniques for TMC OA: The resection interposition suspension arthroplasty using a part of the flexor carpi radialis tendon as interpositional material and using the GraftJacket as interpositional material. 