There is currently no consensus on the best surgical approach for carpometacarpal osteoarthritis treatment. Simple trapeziectomy (TI) or trapeziectomy with ligament reconstruction tendon interposition (LRTI) are both accepted procedures but evidence is lacking. We want to conduct a high quality prospective randomized trial in which preoperative and postoperative objective and subjective outcome measures of both procedures will be compared.

In this trial, investigators compare the Weilby procedure (LRTI) to simple trapeziectomy (TI) with shame incisions in patients with severe trapeziometacarpal osteoarthritis. Investigators hypothesize that TI will be equal to LRTI in terms of both subjective and objective outcome measures

Trapeziometacarpal (TM) osteoarthritis is the second most common location of osteoarthritis in the hand and one of the most common arthritis sites of all joints. The prevalence of isolated radiographic TM joint arthritis is 35% in people older than 55 years. Armstrong et al. reported TM joint arthritis prevalence of 33% in postmenopausal women, of which one third was symptomatic and prevalence of 11% in men older than 55 years. A pathology involving thumb TM joint may lead to functional disability of the entire hand due to pain, weakened pinch/grip strength and decreased thumb opposition. The most common classification system described is Eaton and Litter using 4 stages of thumb TM joint arthritis. The indication for surgical treatment includes pain, TM joint deformity, grip weakness that interfere with daily functions and no response to conservative treatment. A variety of different procedures has been proposed for treatment of TM arthritis. For less severe stages (Eaton-Littler type 1 and 2) operative options include hemi-trapeziectomy, volar ligament reconstruction, thumb metacarpal osteotomy and arthroscopically assisted debridement/synovectomy of the TM joint.For more severe stages (Eaton-Littler type 3 and 4) TM joint arthrodesis, TM primary joint arthroplasty, trapeziectomy alone or combined with use of ligament augmentation.

Limitation of TM joint arthrodesis includes risk of nonunion, decreased thumb motion and degenerative changes to adjacent joints. TM joint arthroplasty leads to fast pain relief, stronger grip function and improved range of motion during short-term postoperative course but long-term risk of implant failure and aseptic loosening has been reported. The aim of trapezial excision is to remove the arthritic TM joint thus reducing pain and maintaining thumb mobility.Several studies have reported excellent results after trapeziectomy.

However, simple excision of the trapezium was criticized for weakening of the thumb, due to instability and proximal migration of the 1. metacarpal. To overcome this issue several surgical technics were described in which trapezium resection is combined with ligament reconstruction tendon interposition (LRTI). Interposition is achieved by placing the rolled-up tendon autograft into the space between the scaphoid and 1. metacarp and stabilization by ligament reconstruction at the base of 1. metacarp. A variety of different LRTI procedures including harvesting of the flexor carpi radialis tendon (FCR), extensor carpi radialis longus tendon (ECRL), abductor pollicis longus tendon (APL) and palmaris have been described.

However, Weilby published in 1988 a method of ligament reconstruction utilizing the half of the width of the flexor carpi radialis tendon (FCR). The strip of the FCR is harvested and coiled around abductor pollicis longus and itself thus restoring metacarpal stability and preventing its subsidence. Today, the Weilby procedure is the most common type of LRTI operations in Denmark. Despite of Weilby's widespread use there is lack of evidence for the superiority of the procedure over simple trapeziectomy in terms of pain reduction, changes in range of motion and muscle strength and studies describes adverse effects of LRTI procedures, which include FCR tendon ruptures or adhesions, scar tenderness, sensory changes, neuromas, complex regional pain syndrome and wound infections.

In contrast, fewer complications and adverse effects have been reported after simple trapeziectomy. In summary, there is insufficient evidence which technique confers a benefit over another technique in terms of pain, physical function, strength and complications. To the investigators knowledge, no trial exist that compared LRTI to simple trapeziectomy with sham surgery.

Inclusion Criteria:

Primary carpometacarpal osteoarthritis Unresponsive to conservative treatment Ability to read and/or understand Danish

Exclusion Criteria:

Rheumatoid arthritis or other types of inflammatory arthritis Previous surgery of the hand TM joint arthritis stage Eaton Litter 1 or 2 TM arthritis due to fracture/dislocation Congenital thumb disorders Other types of surgery in addition to trapeziectomy / Weilby

In the TI group, two shame incisions will be performed to mimic those, incisions made during FCR tendon harvesting in the LRTI group. Hence, blinding to treatment allocation of patients, physiotherapists and health care providers will be possible. Furthermore, independent data collectors will be responsible for baseline and follow-up assessments, while all self-reported outcome questionnaires are made available to the patients electronically, and responses entered into a database identified by identification numbers only. The data analyst will be unaware of the treatment allocation as data will be analyzed using recoded identification numbers. An independent person will perform the recoding