Postoperative Therapy After Interposition Arthroplasty in CMC1

In this randomized controlled trial the investigators want to investigate whether early versus late mobilisation after surgery in the first carpometacarpal joint (CMC1) leads to a faster recovery of hand function. The investigators also want to explore patients' satisfaction with the two different treatment regimes. The participants in the control group will receive the standard treatment at Diakonhjemmet hospital: immobilisation of the thumb in a splint for six weeks. The participants in the intervention group will use a soft splint for six weeks, but will be instructed to remove the splint daily to perform exercises for the thumb. A total of 70 patients will be included in the study.

Osteoarthritis, CMC1-joint, Postoperative therapy, Interposition arthroplasty of the thumb, Occupational therapy

Current standard procedure: Mobilisation at six weeks after operation. The participants will wear a rigid splint for six weeks.

Comparison of early (two weeks) and conservative (six weeks) mobilisation after operation. Comparison of rigid and soft thumb splint.

The COPM-assessment starts with an interview, addressing patient specific Hand Osteoarthritis (HOA)-related activity limitations within the areas self-care, productivity and leisure. The patient will thereafter rate the five most important activities for performance and satisfaction with performance, on 1 to 10-point scales (higher scores reflect better performance or higher satisfaction). The Norwegian version of the COPM has been tested for validity, reliability and responsiveness and has demonstrated good ability to detect functional changes in HOA.

Each patient will be asked to complete a Numeric Rating Scale in order to give an opinion about their postoperative treatment regimen (splint-use, hand function, pain in the thumb, thumb movement and satisfaction with the operation).

MAP-hand is a questionnaire consisting of questions about 18 standardised activities. The patients will be instructed to score their ability to perform the activities on a scale from 1(No difficulty)to 4 (Not able to do). The Norwegian version of the MAP-hand has been tested for validity, reliability and responsiveness.

The electronical instrument Grippit will be used to measure grip force and pinch grip. In Grippit, force recordings in Newtons (N) are displayed on the electronic unit every 0.5 seconds over a period of 10 seconds. The peak and average of the 20 registrations, as well as the final value (last recording) will be recorded.

The flexion deficit of fingers 2 - 5 will be assessed by measuring the distance between the distal nail and the proximal crease inside the hand in millimeters. Range of motion in the thumbs metacarpophalangeal and interphalangeal joints will be measured with a goniometer. The palmar abduction of the CMC1 and of the entire thumb will be measured with the Pollexograph.

Pain will be measured on a numeric rating scale (NRS), (0-10, 0=no pain), by asking the patients to mark the level of pain experienced both while they are resting and during resisted motion when measuring grip force and pinch grip.

The patients will be asked to report which date they performed exercises, which exercises they performed and how much pain they experienced after performing the exercises. They will also be encouraged to write down their own comments /reflections regarding the training.

Inclusion Criteria: Osteoarthritis in CMC1 diagnosed by radiography and a surgeon. Planned surgery(interposition arthroplasty) in CMC1 Ability to communicate in Norwegian Exclusion Criteria: Surgery involving other joints of the hand in addition to CMC1. Previous surgery of the same thumb. Other diseases og injuries that could influence hand function. Mental or cognitive deficit.