Distraction Versus Interposition Arthroplasty for Thumb Carpometacarpal Joint Osteoarthritis: A Randomized Controlled Trial

Osteoarthritis is a degenerative disease of the joints, mostly known for the hip and the knee. Osteoarthritis of the thumb carpometacarpal joint is a common cause for pain, stiffness and grip weakness of the hand, affecting one of three females and one of eight males. Surgical management is indicated when conservative measures have failed, and numerous techniques have been proposed. Distraction arthroplasty has been the gold standard due to lack of high quality evidence, which renders the benefits or harms of other techniques uncertain. A recent Cochrane review was unable to demonstrate whether any technique confers a benefit over distraction arthroplasty and noted that the quality of evidence was low.

Hematoma arthroplasty includes trapeziectomy without interposition of any material or ligament reconstruction. Later, the same technique with the addition of a temporary K-wire stabilization of the first metacarpal has been described it as hematoma and distraction arthroplasty. They immobilized the metacarpal in an overcorrected position to avoid postoperative weakness, assuming the causative factor was the subsidence of the metacarpal into the trapezial void, and they reported improved outcomes. The other treatment alternatives share at least partial excision of the trapezium, and include ligament reconstruction alone or with tendon interposition, allograft interposition arthroplasty, prosthetic implants and arthrodesis. A recent promising technique is the pillow technique, a type of interposition arthroplasty, which utilizes a fascia lata allograft as interposition material and stabilization with a K-wire. The technique showed promising results in a long-term follow-up study, and proved to be a viable alternative to distraction arthroplasty with no donor site morbidity and better preservation of the height of the metacarpal. However, there is no robust evidence that retaining the joint space affects the functional results or the grip strength of the patients.

Aim of the study In view of the low quality evidence regarding the use of interposition material versus distraction arthroplasty alone, the investigators will compare the two methods in a prospective randomized study design. Hypothesis of the study is that interposition arthroplasty using the pillow technique yields better results in terms of functional improvement and grip strength when compared to the hematoma and distraction technique. The confirmation of the hypothesis is going to justify the use of the fascia lata in the procedure, which is one option widely utilized. On the contrary, if the pillow technique fails to yield clinically meaningful results, the recommendation of the hematoma and distraction technique will account for reducing the overall cost of the procedure, rendering the allograft redundant.

The study will be conducted in accordance with the Declaration of Helsinki and the Guidelines on Good Clinical Practice.