Distractie van het duimbasisgewricht: 6 versus 8 weken.

Joint distraction for first carpometacarpal (CMC1) OA is a technical feasible and innovative therapy for relatively young patients with severe symptoms. Spaans et al. conclude that joint distraction can provide clinical benefits in patients with CMC1 joint OA. It could result in postponing invasive surgical interventions for CMC1 OA. In this recent prospective pilot study five patients were treated and show favorable results - reduction of pain and improvement of function at one year. Nowadays 40 patients are treated with CMC1 joint distraction. On average, patients report less pain and better physical function compared to pre-operative scores. Two years post-operatively, the average clinical parameters further improved over time.
Among patients suffering from ankle and knee OA, joint distraction is an accepted treatment with excellent results, clinical improvement, and repair of joint cartilage. Van der Woude et al. shows that five years post-treatment, patients still report clinical improvement. In this study, all patients (n = 20) had the external distractor device in place for a duration of 8 weeks. A more recent study performed by the same research team shows that six weeks of distraction therapy has similar 1-year results compared to eight weeks of joint distraction. In comparison, patients in the six-week group had significantly less pin tract infections during the distraction period than patients in the eight-week group (55% versus 85% respectively; p = 0.038). It is also thought that the distracted joint will be less stiff when immobilized for a shorter period of time. In daily clinical practise the treatment of knee distraction has been reduced to a period of 6 weeks nowadays. It is unknown if six weeks of distraction is also sufficient for clinical improvements among patients with symptoms of CMC1 OA.
Therefore, this study will test the primary hypothesis that there is a difference in PROMIS Physical Function Upper Extremity Short Form (PROMIS UE SF) score at 1 year after 6 or 8 weeks of first carpometacarpal joint distraction.

This study will test the primary hypothesis that there is a difference in PROMIS Physical Function Upper Extremity Short Form (PROMIS UE SF) score at 1 year after 6 or 8 weeks of first carpometacarpal joint distraction.

3/4 weeks (Group A/B), 6/8weeks (Group A/B), 3 months, 6 months, 12 months, 2 years and 5 years post-distraction

A standard hand distraction device will be placed over the affected CMC1 joint. The external fixator will be anchored transcutaneous with 2 proximal pins in the trapezium and two distal pins in the first metacarpal. The device will bridge the CMC1 joint. Intra-operatively the joint will be distracted 3.0 mm. This will be checked on X-ray. The distractor is left in situ for a total period of 6 (Group A) weeks or 8 (Group B) weeks. To protect the distractor and to prevent inconveniences to the patient due to the distractor, a custom-made brace will be fitted to cover the distractor. Hygiene instructions regarding pin entry point maintenance will be given and evaluated during postoperative visits. For patients in group A the device will be removed 6 after placing, for patients in group B the device will be removed 8 weeks after placing, both in the outpatient clinic and followed by standard care physical therapy.