The burning, grinding pain of thumb arthritis disrupts daily life for one in four older adults in Canada. Thumb splints can reduce pain and improve hand function, and now, a Western University researcher in London, Ont. is working to bring custom 3D-printed splints to patients who can't access specialist clinics.
Joy MacDermid, a physiotherapy professor in the Faculty of Health Sciences and a member of Western's Bone and Joint Institute, received an Ignite Innovation Grant from the Arthritis Society of Canada to fund the second phase of her study. It will improve care for people with carpometacarpal (CMC) - thumb arthritis - a condition that occurs when cartilage breaks down at the base of the thumb, causing joint pain, stiffness and weakened grip.
"We see a lot of women over 50 with thumb arthritis, especially those doing physical work," MacDermid said. "They struggle with daily activities like turning a key or caring for grandchildren."
The current standard of care requires a hand therapist to see the patient in person, assess their hand and mold a thermoplastic splint directly onto it. Though a proven process, it depends on physical proximity to a specialist clinic. MacDermid and her team are devising a new solution that doesn't require in-person visits.
Splints improve joint alignment in thumb arthritis
As co-director of the clinical research lab at Roth | McFarlane Hand & Upper Limb Centre (Roth | McFarlane) and a scientist at Lawson Research Institute (Lawson) of St. Joseph's Health Care London, MacDermid leads researchers studying how to measure, predict and reduce upper extremity disability.
Marjan Saeedi, a physical therapy PhD candidate, is part of the team at Roth | McFarlane.
"Over time, the CMC joint becomes unstable and misaligned due to cartilage degeneration, affecting the ligaments and muscles as well. Because we use our thumbs constantly, the misalignment and pain worsens," she said. "A splint helps support joint alignment. It's even helpful following joint replacement surgery."
Western engineering professor and Lawson scientist Louis Ferreira led an earlier Mitacs-funded study with MacDermid and Belgian industry partner Orfit to develop a remote splint-making process using new materials and new 3D hand-scanning technology: an iPhone scanning app or a custom scanner developed in Ferreira's bioengineering lab. Without the patient being present, the scans captured the precise measurements needed to fabricate 3D-printed custom splints.
MacDermid's team also developed a clinical app to remotely assess a patient's pain levels, hand function and splint requirements, replicating the intake process normally done in person. The prototypes made with the new process showed promise.
"The question now is whether people can use the new methods in routine clinical practice," MacDermid said.
Implementing, testing the innovative thumb splint
MacDermid is leading an Arthritis Society Ignite Grant evaluating how hand therapists use the new process and how patients respond to the 3D-printed splints compared to conventional ones. Her team hopes to scale up the new process by running workshops to train hand therapists at Roth | McFarlane and in community-based clinics across London, Ont. They're also evaluating scanners that offer more precision than iPhone apps, without the cost of their custom device.
Patient wearing (top) 3D-printed thumb splints and (bottom) traditionally fabricated splints. (Submitted)
In the trial of the 3D-printed solution, patients receive both a traditionally fabricated splint and a digitally produced one, wearing each for six weeks while researchers assess hand strength, pain levels and patient preference.
"Most were really eager to try the 3D-printed version," said Saeedi. "The perforations from the printing process improve air circulation, and female patients liked its smaller size and the option to choose the colour, making it like an accessory on their hand."
Saeedi is writing her dissertation on what makes patients adhere to consistent use of their splints. Pain relief and comfort top the list, though she has also documented a motivator outside of its main clinical use.
"Patients say, 'I can wear it when my grandchildren are around or on public transit, without worrying about pain or further injury if it gets bumped or jostled'," Saeedi said. "That sense of protection helps keep them using it."
Addressing access barriers in thumb arthritis treatment
The remotely designed, 3D-printed splint is not intended to replace traditional care, but to remove barriers to accessing care.
"Some of our clients are driving from Owen Sound or Sarnia or Windsor, in the middle of winter," MacDermid said. "In the future, if their splint gets damaged or their hand changes, we would be able to reprint it from the pattern in our system and mail it to them - no return trip needed."
(L to R) Western PhD candidate Marjan Saeedi; Western postdoctoral student and co-principal investigator, Maryam Farzad; research co-ordinator at the Roth | McFarlane Hand and Upper Limb Centre, Katrina Munro; and principal investigator and Western physiotherapy professor Joy MacDermid are part of a research team that aims to make 3D-printed thumb splints accessible to patients no matter where they live. (Colleen MacDonald/Western News)
The Ignite Grant includes funding for MacDermid's team to adapt their process to make splints for patients recovering from surgery or injections to treat Dupuytren's contracture, a separate hand condition that causes fingers to permanently bend inward due to thickening and shortening of connective tissue in the palm.
MacDermid attributes the project's success from the beginning to contributions from many grad students and postdoctoral scholars across faculties, including those Ferreira supervised.
"This project is genuinely interdisciplinary. We simply can't do the clinical work without the engineering, and vice versa," she said.
MacDermid says the future of the project could reach communities with some clinical infrastructure but no hand specialist. Going further still, with the help of AI-assisted remote scanning, the process would enable people in remote locations like the Arctic, with no local clinical support at all, to access custom splints.
For now, the project is already attracting interest from therapists in other provinces who want to attend the workshops.
"That would be a substantial accomplishment to spread a working clinical process across Canada," MacDermid said. "This technology could make a real difference for people who currently aren't getting care at all due to distance, disability or the absence of specialist care."
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