RegJoint™ Implant in Thumb Base Osteoarthritis – Early Challenges Identified (2019)
Mattila, Haapamäki & Waris (2019) evaluated the use of the RegJoint™ implant in 34 patients (38 hands) undergoing total trapeziectomy for thumb carpometacarpal (TMC) osteoarthritis. The average follow-up was 33 months. Clinical results were found satisfactory, but the signs of osteolysis were noted.
Key findings according to them:
- Significant improvement in pain and hand function
- Osteolysis observed in 24 cases at 18 months
- 3 patients developed foreign-body reactions; one required revision surgery
- The implant did not prevent collapse of the resection space
- Authors recommend reconsidering the use of RegJoint™
Their conclusion:
Despite satisfactory clinical outcomes, the risk of foreign-body reactions and osteolysis raises concerns. The RegJoint™ implant may not offer added value in treating TMC osteoarthritis.
Commentary from Scaffdex Oy: The study by Mattila et al. lacks a comparison with standard treatments (e.g., simple trapeziectomy), making it difficult to assess the added value of the RegJoint™ implant. As being a retrospective study, a mean follow-up of 33 months is relatively short for evaluating long-term safety and efficacy of bioabsorbable implants. Retrospective studies are prone to selection bias and lacks the rigor of randomized controlled trials.
Despite good clinical outcomes, the frequent occurrence of osteolysis and tissue reactions raises concerns about implant biocompatibility. We would like to highlight that even if osteolysis occurs, this has not yet been showed to have clinical importance. Radiological findings showed significant changes, but these did not always correlate with symptoms, potentially underestimating long-term benefits and risks.
Full reference, link to publication below: Mattila, S., Haapamäki, V., & Waris, E. (2020). Unfavourable early outcomes of total trapeziectomy with RegJointTM interposition: a report of 38 osteoarthritic hands in 34 patients. The Journal of Hand Surgery, European Volume, 45(2), 167–172. https://doi.org/10.1177/1753193419885272.