2022-051 – Implantable Trapezium Prosthetic for Arthritis in the Thumb CMC Joint

Background:
Thumb carpometacarpal (CMC) arthritis is a common affliction that most frequently occurs with aging, or sometimes with damage when the cartilage at the trapezium and the metacarpal wears away. The result is bone-on-bone contact, which roughens the surface of the joint and causes friction. Patients can experience swelling, pain, stiffness, decreased range of motion, and diminished grip strength. All symptoms can range from minor to debilitating. In early stages it can be treated with splints and braces, but as it progresses, surgery is often required. The most frequently used surgical procedure for thumb CMC arthritis is the Ligament Reconstruction and Tendon Interposition (LRTI) surgery. This surgery does offer some pain relief and, by extension, range of motion restoration. However, grip strength is reduced significantly due to shortening of the thumb by removal of the trapezium and redirection of tendons in the hand. Many surgical devices have been invented in an attempt to improve surgical reconstruction of arthritic CMC joints, yet they have not been highly successful. These devices typically fail due to poor design issues related to bone adherence, poor strength of materials used, over complication, and/or maintenance of thumb length. But the most common source of failure is instability due to the highly unconstrained nature of the joint.

Consultation with hand and wrist orthopedic specialists revealed that many of the above shortcomings make most existing surgical devices and/or procedures unpreferable or less than ideal. Luckily, there is one surgery that solves most of these issues. Thumb CMC Arthrodesis resolves the challenges of CMC joint repair by fusing the trapezium to the thumb metacarpal, maintaining thumb length and preserving tendon form and tension in the joint area. This results in excellent pain relief, grip strength, and overall patient satisfaction. Despite effective outcomes, recovery times for this surgery are extensive - typically requiring 6 weeks in a cast and then several more months before the bones have fully fused. Reduced range of motion is common and the surgery itself can be challenging to perform. Therefore, an effective surgical solution is still needed to overcome the numerous pitfalls and long recovery periods associated with existing technologies. Furthermore, a surgical solution that can be used in the setting of failed primary thumb CMC arthroplasty, such as LRTI, is strongly desired.

Technology Description:
Researchers at University of New Mexico have designed an implantable prosthetic as a novel approach to surgically resolve CMC joint arthritis symptoms. The implant is designed to obtain the same beneficial outcomes of CMC Arthrodesis fusion surgery with the use of original technology. By utilizing the same approach as thumb CMC fusion surgery, pitfalls of reduced strength, constraint problems, and high failure rates are avoided, but without the challenging procedure and recovery period associated with the fusion surgery. These achievements are made through several unique design characteristics and implant placement. The proposed implantable prosthetic is capable of replacing arthritically damaged bone, offering pain relief as it eliminates bone-on-bone contact in the inflamed joints. In addition, the implant design is capable of preventing strength loss that results from shortening of the thumb and can maintain excellent stability in the joint to avoid failures of previous technology.

Website:

https://unm.flintbox.com/technologies/B104232ECBCB4B86AB508AFB4E2A1CBD

Advantages:

  • Effectively eliminates arthritis in the patient
  • Shortened recovery period after surgery
  • Offers pain relief
  • Maintains thumb length, preventing grip strength loss
  • Excellent strength, stability, and durability

Potential Applications:

  • Arthritis solution
  • Hand Surgery
  • Medical Devices

Contact Information:

Name: Gregg Benninger

Email: GBanninger@innovations.unm.edu

Phone: 505-272-7908