The Department of Orthopaedic Surgery and Rehabilitation

Hand Surgery

 

Research History and Capabilities

The biomechanics and basic hand surgery research efforts of the current Division of Hand Surgery in the Department of Orthopaedics and Rehabilitation at the University of Texas Medical Branch in Galveston, Texas began in 1984. The initial efforts were spearheaded by Steven F. Viegas, M.D. and Allen Tencer, Ph.D. utilizing Pressure sensitive Fuji film. The group was soon joined by Dr. Rita Patterson who assumed an increasing roll in and direction of the research efforts following Dr. Tencer’s departure in 1985.  Since then the Hand Surgery Division has continued to be dedicated to furthering knowledge in the area of wrist anatomy, kinematics and kinetics. It has been extremely productive under the direction of Rita Patterson, Ph.D. along with the efforts of a long list medical students, orthopaedic residents, international research fellows, doctorate, and post doctorate students as well as a variety of other collaborators.  This overview of some of the past efforts and our current capabilities is a tribute and a thanks to all those that have previously passed through our laboratory and our lives, who currently share them.  And to those future visitors, colleagues and friends, we look forward to our time together. 

Clarence “Nic” Nicodemous joined us in 1992, first as a doctoral student and subsequently stayed on adding to our expertise in the field of kinematics. Bill Buford, Ph.D. also joined our effort arriving from the Carville Hospital in Louisiana where he had previously worked with Dr. Dan Riordan and Dr. Paul Brand.

Our current capabilities include research in basic anatomy, comparative anatomy, load mechanics (kinetics), kinematics, 3-D image analysis, computer animation and modeling.

The original UTMB medical school building which was built in 1891 and restored in 1994  is the location of a wonderful anatomy lab on its top floor, which offers ample access to both fresh and embalmed cadaver specimens (Figure 1) with the assistance and continued support of  the Anatomy Department.  Much of our detailed dissection (Figure 2) is carried out in the Orthopaedic Biomechanics Lab in Rebecca Sealy Hospital (Figure 3).  Previous anatomy studies have among other things identified two distinct types of carpal morphology of the wrist most evident by different shapes of the lunate, of which the Type 1 lunate has a single distal surface which articulates with the capitate while the Type 2 lunate has two distinct distal surfaces one facet articulating with the capitate and the other with the hamate (Figure 4). Anatomy dissections and sections through the wrist demonstrate the differences between these two basic patterns of carpal morphology (Figure 5, Figure 6, Figure 7 and Figure 8). These differences in some cases can be seen on radiographs (Figure 9) but are not always easily or reliably identified.  Anatomy studies have also identified that the most common location of degenerative changes in the wrist was identified to be at the proximal pole of the hamate (Figure 10 and Figure 11) which was found to have a strong correlation with the presence of the type 2 lunate.

The Biomechanics laboratory also has the capabilities to study the particular properties of the ligaments which include precise measurements of the dimensions of a ligament (Figure 12) and testing of specific mechanical properties of the ligaments (Figure 13).

With this strong interest in the anatomy of the human wrist, studies of variability and comparative anatomy (Figure 14) have been conducted and continue (Figure 15). 

Specific programming has been developed at UTMB for edge identification and contouring to allow the accurate and quantifiable reproduction and study of three dimensional models of the skeletal anatomy based on two dimensional CT scans. This process begins with an individual CT scan (Figure 16) which is analyzed by an automated edge identification and contouring program (Figure 17). Individual contours of the bone are assembled (Figure 18) and surface tiling programs with color and shading capabilities allow for the construction of a three dimensional image of a bone such as the scaphoid (Figure 19) or the entire wrist which can be seen from any perspective, such as the dorsal view (Figure 20) or the carpal tunnel view (Figure 21).

Pressure sensitive Fuji film has been utilized to study the contact areas and pressures with in the wrist joint in a variety of conditions including the normal wrist in various positions under various magnitudes of load and/or load paths, various ligament injuries,  fracture patterns and various types of surgical procedures.  The Fuji pressure sensitive film has increasing red coloration with increasing load (Figure 22). A dorsal opening in the dorsal wrist capsule is made and an external marker is affixed to the dorsal radius (Figure 23). The Fuji film transducer can be made with the two components of the film (Figure 24) and placed in to the wrist joint (Figure 25). The wrist can then be loaded (Figure 26) resulting in red coloration on the pressure sensitive film at the external marker and under the scaphoid and lunate where they would contact and load the radius (Figure 27). This pressure sensitive film is then analyzed to give area and pressure data (Figure 28). This data can be utilized to show the changing pattern of contact on the radius as in Figure 29 which compares on the left, a pressure sensitive film print of a normal wrist in one position and load where most of the red imprint is located in an area between the lunate and the radius, while on the right side of the figure most of the red imprint has shifted to the scaphoid fossa where the same wrist was used in the same position and with the same magnitude of load the only difference being a scapholunate dissociation was surgically simulated. The pressure sensitive film studies have always, as in this case, revealed that the areas of increased load coincide with where we see joint space narrowing and arthritis develop in the clinical conditions that are simulated such as on the x-ray in Figure 30 where the arrow points to the joint surface which coincides with that so-called SLAC wrist (scapholunate advance collapse). Other pressure film studies have included the study of the proximal pole fracture of the scaphoid where Fuji film imprints again show a good correlation between increased load and the development of arthritis. Figure 31 shows increased load (red coloration) between the distal scaphoid fragment and the radial styloid which coincides with the area where degenerative changes are seen in a long standing scaphoid non-union of the proximal pole (Figure 32). The pressure sensitive film studies have also shown a good correlation between a decrease or no change in load and absence of arthritic changes Figure 33 shows decreased or no change in load (red coloration) under the proximal pole of the scaphoid and the lunate where the joint space between the proximal pole of the scaphoid and the radius, and between the lunate and the radius are maintained and do not develop degenerative changes, even in a long standing non-union of the proximal pole of the scaphoid (Figure 34) .

Over more recent years there has been an increased interest and efforts mounted to study the kinematics of the wrist and its individual carpal bones. This is accomplished by a combination of CT imaging and reconstruction, with motion analysis systems.   Under fluoroscopic control (Figure 35) triad video reflective pins are placed in the specific bones which are targeted for study (Figure 36).  Tendons are dissected  free to allow loading and motion of the wrist (Figure 37). The upper extremity is mounted to an apparatus (Figure 38) which allows passive or indirect active mobilization of the wrist (Figure 39). The wrist is mobilized and six cameras of the motion analysis system track the external pin markers attached to the targeted bones while the wrist is going through its range of motion (Figure 40). Before and after motion analysis CT scans are obtained with the triad pins in place (Figure 41). Individual CT scans, some of which include the triad pins (Figure 42) are utilized to reconstruct the individual carpal bones along with the video reflective balls of each individual triad pin (Figure 43). This allows the visualization of instantaneous screw axes (Figure 44), the equivalent of time lapse progressive and changing positions of one bone relative to another fixed bone (Figure 45) and with the analysis of the images, the proximity of the subchondral bone between two bones within given ranges (Figure 46), which is an indirect and noninvasive way to analyze the inferred contact, can be mapped. This is an alternative to using pressure sensitive film (Figure 47) which has the added benefit of being able to noninvasively and simultaneously demonstrate the proximity mappings (areas of inferred contact) in the radiocarpal joint (Figure 48), midcarpal joint (Figure 49) carpometacarpal joints (Figure 50), distal radioulnar joint (Figure 51) and virtually any other within the reconstructed image.

All of these resources can be utilized to study an area such as the scaphotrapeziotrapezoid joint. We can document the skeletal variations such as the presence or absence of and interfacet ridge on the distal articular surface of the scaphoid (Figure 52), study the anatomy of the associated ligaments (Figure 53) to hypothesis the relationship of the soft tissue ligamentous anatomy and the skeletal morphology with its impact on and constraints to the motions of that joint (Figure 54 and Figure 55) and test and demonstrate the kinematics of that joint. (Figure 56 and Figure 57). This has been done with the STT joint and what the skeletal and ligamentous anatomy suggested was the motion is constrained to an axis of rotation which runs essentially perpendicular to the orientation of the interfacet ridge which aligns with the scaphotrapeziotrapezoid ligament attachment on the scaphoid and scaphocapitate ligament and this motion plane is the same whether the wrist as a whole is moving in flexion extension or radioulnar deviation.

Many other studies are on going and still more are targeted for future times and visitors who wish to participate in research in the field of the hand, wrist, forearm and elbow and to share in our enthusiasm and enjoyment in research.

If you are interested in the research opportunities in the Orthopaedic Biomechanics Lab under the Division of Hand Surgery feel free to contact Dr. Rita Pattterson (rpatters@utmb.edu), 301 University Blvd., Galveston, Texas 77555-0892 or Dr. Steven Viegas (sviegas@utmb.edu), 301 University Blvd., Galveston, Texas 77555-1350 or you may check with the American Orthopaedic Association listing under the International Center for Orthopaedic Education.

 

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