The use of the RegJoint™ implant for base of thumb osteoarthritis: Results with a minimum follow-up of 2 years.

The RegJoint™ (Scaffdex Oy, Finland) implant is a bio-absorbable poly-L/D-lactide implant which acts as a temporary support in resected joint spaces. It can be used in base of thumb surgery as a spacer to prevent first metacarpal subsidence. However, high rates of adverse tissue reactions and bone osteolysis have been reported recently by one group. The objective of this study was to investigate the outcome of patients treated in our institution with this implant. Patients underwent a postoperative clinical and radiological assessment. The QuickDASH questionnaire, Patient Evaluation Measure (PEM) and a visual analogue scale for pain assessment were used. Grip strength, key pinch, pinch strength, thumb palmar and radial abduction and opposition were measured. Trapeziometacarpal height was used to evaluate thumb shortening compared with the preoperative value. Periprosthetic bone-erosion of the trapezium and metacarpal were measured. Subluxation of the joint was evaluated by measuring the step-off between the radial edge of the trapezium and the base of the first metacarpal bone. Twenty-two patients from 2013-2016 were included. There were no postoperative wound complications. There was no significant difference in grip strength, key pinch or pinch between the operated and the contralateral hand. There was no significant difference in the trapeziometacarpal height, trapezial height or the degree of subluxation pre-or post-operatively. Contrary to recent reports, we did not find any adverse soft tissue reactions or significant bone erosion. There was no significant change in hand function. We consider the RegJoint™ a useful adjunct in the management of a select cohort of patients with base of thumb arthritis.