The Trapeziometacarpal Joint: Tissue Characterization and Surgical Techniques for Treatment of Osteoarthritis

The trapeziometacarpal (TMC) joint is one of the most important joints in the human body. It provides the thumb with the ability to cross over the palm of the hand, thus enabling motions of pinch and grip essential in performing routine daily activities. In the case of repeated use of this joint, the articular cartilage may wear through a progressive joint disease known as osteoarthritis (OA). This disease is characterized by pain at the base of the thumb, decreased range of motion, thumb instability, and decreased grip and pinch strength leading to impairment in vocational activities, significantly affecting quality of life. Much of the research surrounding the TMC joint has focused on development of non-surgical and surgical options for treatment of early and late stage OA. Unfortunately, the extent of research on characterizing the biophysical properties of the TMC joint and surrounding tissue is limited. The following research will seek to identify the ligamentous structures hypothesized to act as primary stabilizers of the TMC joint through advanced, high-resolution motion analyses. Mechanical properties of the primary ligamentous stabilizers will be obtained through uniaxial tensile testing of ligamentous tissue. This tissue will be further characterized through histology, staining for identification of the presence and orientation of essential proteins which may serve to support the argument for primary stabilizing tissue. Using results from the tissue characterization studies, two techniques are presented for the treatment of early and late stage TMC joint osteoarthris, which are designed to maintain and/or regain stability of this joint. The final section introduces a methodology for development of patient-specific computational finite element models of the hand and thumb. Input properties of these models are based on computed tomography data and outputs from the motion analysis and mechanical testing studies

Patterns in Bone Drilling Performance Before and After the 2017 Motors Skills Course of the Southwest Orthopaedic Trauma Association

Background: Although experience within the operating room can help surgeons learn simple bone-drilling techniques, outside training may be better suited for complex procedures. We adapted a rotary handpiece to evaluate bone drilling skills of orthopaedic resident physicians during the 2017 motor skills course of the Southwest Orthopaedic Trauma Association (SWOTA). Methods: A total of 25 postgraduate year-one orthopaedic residents from seven institutions were asked to perform a bicortical drilling task three times before and after attending a motor skills course. Kinetic and kinematic data were collected using force, acceleration, and visual sensors. Results: A total of 16 parameters were measured. Variables statistically significant after the course were as follows: over-penetration (28.8-18.2 mm), skiving (22%-6%), preparation time (27.3-9.65 seconds), drilling time (8.28-9.35 seconds), palmar-dorsal vibration (1.76- 2.05 m/s2), maximum drilling force (58.56-84.30 N), and maximum revolution per minute (RPM; 917-944). The interdependence of these parameters taken separately for pre- and post-course performance are presented. Notable correlations include: over-penetration with force (0.65), palmar-dorsal toggle (0.65), vibration in palmar-dorsal (0.53), time (-0.41), and RPM (-0.36); time with both RPM (0.38) and palmar-dorsal toggle (-0.40); and force with both RPM (-0.41) and palmardorsal toggle (0.32). Conclusions: The correlation data presented provide insight into patterns between measured parameters regarding where performance metrics are and are not coupled. Evidence for motor skill acquisition across both short- and long-time scales are elucidated

Design of a Robotic Apparatus for Simulated Motion of the Human Hand

Background: The hand is complex, in that any small disturbance to the flexor tendons, extensor tendons, and intrinsic muscles can result in dysfunction of the entire structure. We designed a robotic device to consistently load a native thumb carpometacarpal (CMC) joint in assessing the effects of ligamentous damage on stability of the thumb CMC joint. Methods: The device consisted of a mechanical plate in which to fixate a cadaveric hand, a tendon-suture routing system, a bracket to couple multiple suture lines to a cable to maintain equal force among sutures and tendons, and the finger-thumb force measurement devices. To apply force to the sutures, a cable was run from the suture coupling device to the tendon actuator and from the finger-thumb force measurement devices to the control system. The device was controlled using a Beaglebone Black microcontroller, load cells, rotary encoders, and a liquid crystal display (ie, LCD) touchscreen interface. Results: The design worked as intended in terms of basic communication, signal processing, and control functions. Cyclic loading resulted in web creep of the tissue. Using closed-loop control, the system was able to settle to a desired load. Conclusions: Use of the current device may result in improved understanding of joint movement within the hand, which may help surgeons in treating associated injuries. Future revisions to the device will aim to improve the hardware and software to accelerate the time to converging to the desired force and displacement

Design for Transtibial Modifiable Socket for Immediate Postoperative Prosthesis

Amputations are long-standing surgical procedures that have been performed for centuries; however, very little attention and urgency have been given to immediate restoration of movement and return to a normal lifestyle. In many cases, the time between amputation and prosthetic fitting can pause recovery and development of new routines. To increase recovery, immediate postoperative prostheses (IPOPs) have been developed yet these are under-utilized because of concerns for wound healing and complications with vascular diseases. Subsequently, we designed a transtibial IPOP that utilizes an ergonomic modifiable socket that allows for examination, wound care, and in situ edema control. Additionally, the IPOP facilitates early weight bearing and protects the amputated limb from external trauma postoperatively. Our purpose is to introduce this technology and describe how its unique design will serve to provide potential benefits and positive effects on patients who have undergone amputations