It is well known that treatment of the old fracture-dislocations of the fifth carpometacarpal (CMC) joint is challenging. For patients with persistent pain due to this condition, numerous surgical techniques have been proposed. Here, we present a novel surgical technique, CMC joint suspension arthroplasty, using a partial slip of the extensor carpi ulnaris tendon. This procedure follows principles similar to the procedure of trapeziectomy with suspension arthroplasty for treatment of thumb CMC joint arthritis. We believe this suspension arthroplasty has several advantages compared with other surgical procedures. First, mobility of the fifth metacarpal is greatly preserved because the fifth metacarpal is stabilized only by the ligament against the fourth metacarpal. Second, the length of the fifth ray can be maintained by adjusting the level of the drill hole of the fourth metacarpal. Third, malrotation of the little finger can be prevented by drilling the holes of the fifth and fourth metacarpals in the proper direction. We believe this surgical technique could be a better treatment option for degenerative arthrosis of the fifth CMC joint.