A team of engineers at the Australian Curtin University has won a $15,000 dollar prize for their 3D printed finger continuous passive motion (CPM) device. Dr. Lei Cui in collaboration with other engineers has developed a relatively low cost method to fabricate custom hinged finger orthoses that can be attached to a linear motor. Each finger consists of eight rigid 3D printed parts connected by pins, and the fit can be customized to the patient/finger. The cost of fabrication is estimated to be about $100 per finger. They are currently exploring commercialization options.
The most common complication after injuries to the hands and fingers is stiffness. Hand therapy is an integral part of the recovery process, and it’s importance has led to a wide assortment of innovative devices. Continuous passive motion devices constantly (and gently) move a joint through a set range of motion. They are most commonly used for the knee. Their use is somewhat controversial currently in the world of orthopedics as their cost can be high and the benefit is still a little unclear. While not used in the hand as frequently, hand CPMs exist and they currently appear to cost around $5k, although actual out-of-pocket costs to patients is difficult to determine.
A randomized controlled trial in the Journal of Hand Surgery from 1998 comparing CPM devices to an active motion protocol in patients undergoing metacarpophalangeal joint arthroplasties found minimal benefit to range of motion and decreased grip strength. Their conclusion was that the cost was not justified. A retrospective study from 2008 in the Journal of Hand Therapy compared patients underoing postoperative rehab with and without CPM following tenolysis surgery.
They found no difference in range of motion between the two groups, and increased use of therapy resources in the CPM group. While the limited research available does not currently appear to support the use of hand CPM devices, this new low-cost 3D printed innovation may re-invigorate finding beneficial patient use cases for hand CPM.