Prototyping a Prosthetic Arm for Ulnar and Radial Deviation

Author(s):  
Robert Kerwin C. Billones ◽  
Joshua M. Lim ◽  
Ricardo Cardenas ◽  
Michael V. Manguerra ◽  
Ryan Rhay P. Vicerra ◽  
...  
Keyword(s):  
1998 ◽  
Vol 1 (2) ◽  
pp. 107-121
Author(s):  
Khaled W. Al-Eisawi ◽  
Carter J. Kerk ◽  
Jerome J. Congleton

This study evaluated wrist strength limitations to manual exertion capability in two-dimensional static biomechanical modeling. The researchers hypothesized that wrist strength does not limit manual exertion capability - an assumption commonly made in many strength biomechanical models. An experiment was conducted on 15 right-handed males of college age. Isometric wrist flexion strength was measured at two elbow angles: 90 degree and 135 degree and in two wrist positions: neutral and 45 degree extended. Isometric wrist radial deviation strength was measured at the same two elbow angles and in two wrist positions: neutral and 30 degree ulnarly deviated. Minimum wrist strength limits for which wrist strength does not limit maximal moments about the elbow in manual hand exertions were calculated and compared to their corresponding measured wrist strength moments using paired t-tests. In general, wrist strength was non-limiting. However, wrist flexion strength in the 45 degree extended wrist posture was limiting. Weak-wrist subjects showed more wrist strength limitations than strong-wrist subjects.


Hand ◽  
2021 ◽  
pp. 155894472110289
Author(s):  
Anthony L. Logli ◽  
Beth A. Schueler ◽  
Laurel A. Littrell ◽  
Sanjeev Kakar

Background We hypothesize that different positions of the wrist in the coronal plane makes the carpus susceptible to ulnar impaction. Methods We prospectively enrolled 10 adult volunteers and obtained fluoroscopic images of each wrist in 12 different positions using a standardized protocol. Distances from the ulna to the lunate (UL) and ulna to the triquetrum (UT) were digitally measured as was the portion of the lunate surface area that was uncovered (LUR) with wrist deviation. Results A wrist position of Pronation, Neutral Deviation, and Grip (P-ND-G) significantly shortened the ulnocarpal distance when compared to a position of Neutral Rotation, Neutral Deviation, and No Grip (NR-ND-NG). Radial deviation during pronation and gripping (Pronated, Radial Deviation, Gripping [P-RD-G]) resulted in the lowest mean UL distance (1.2 mm). UT distance was minimized by a position of ulnar deviation during a pronated grip (Pronated, Ulnar Deviation, Gripping [P-UD-G]) (3.1 mm). The lunate becomes more uncovered with radial deviation. Conclusion Radial deviation minimizes the UL distance while ulnar deviation minimizes the UT distance during a wrist position of pronation and gripping. Further, there is more proximal lunate surface area uncoverage during all positions of radial deviation compared to ulnar deviation.


2021 ◽  
Vol 46 (4) ◽  
pp. 352-359
Author(s):  
Susumu Saito ◽  
Itaru Tsuge ◽  
Hiroki Yamanaka ◽  
Naoki Morimoto

Wassel VI radial polydactyly is associated with metacarpal adduction and radial deviation of the metacarpophalangeal joint of the ulnar duplicate. The soft tissue abnormalities responsible for these deformities were characterized using preoperative multi-planar three-dimensional ultrasound and intraoperative observation in four patients. In all patients, the abductor pollicis brevis and superficial head of the flexor pollicis brevis inserted into the radial first metacarpal, whereas the adductor pollicis and deep head of the flexor pollicis brevis inserted into the ulnar thumb. Aberrant location of the flexor pollicis longus and absence of the A1 pulley system was associated with severe radial deviation. An additional superficial thenar muscle along the ulnar metacarpal was associated with minimal metacarpal adduction. Uneven forces on the ulnar duplicate could be associated with these characteristic deformities and joint instability. Knowledge of these abnormalities allows better planning of surgery and further insight into this rare radial polydactyly configuration. Level of evidence: II


Author(s):  
Katherine R. Lehman ◽  
W. Gary Allread ◽  
P. Lawrence Wright ◽  
William S. Marras

A laboratory experiment was conducted to determine whether grip force capabilities are lower when the wrist is moved than in a static position. The purpose was to determine the wrist velocity levels and wrist postures that had the most significant effect on grip force. Maximum grip forces of five male and five female subjects were determined under both static and dynamic conditions. The dominant wrist of each subject was secured to a CYBEX II dynamometer and grip force was collected during isokinetic wrist deviations for four directions of motion (flexion to extension, extension to flexion, radial to ulnar, and ulnar to radial). Six different velocity levels were analyzed and grip forces were recorded at specific wrist positions throughout each range of movement. For flexion-extension motions, wrist positions from 45 degrees flexion to 45 degrees extension were analyzed whereas positions from 20 degrees radial deviation to 20 degrees ulnar deviation were studied for radial-ulnar activity. Isometric exertions were also performed at each desired wrist position. Results showed that, for all directions of motion, grip forces for all isokinetic conditions were significantly lower than for the isometric exertions. Lower grip forces were exhibited at extreme wrist flexion and extreme radial and ulnar positions for both static and dynamic conditions. The direction of motion was also found to affect grip strength; extension to flexion exertions produced larger grip forces than flexion to extension exertions and radial to ulnar motion showed larger grip forces than ulnar to radial deviation. Although, males produced larger grip forces than females in all exertions, significant interactions between gender and velocity were noted.


2011 ◽  
Vol 46 (5) ◽  
pp. 574-576 ◽  
Author(s):  
Steve M. Patterson ◽  
William J. Picconatto ◽  
Julie A. Alexander ◽  
Rachel L. Johnson

Objective: To present the case of an acute traumatic extensor carpi ulnaris (ECU) subluxation in a National Collegiate Athletic Association Division II female basketball player. Background: The ECU tendon is stabilized in the ulnar groove by a subsheath located inferior to the extensor retinaculum. The subsheath can be injured with forced supination, ulnar deviation, and wrist flexion, resulting in the ECU tendon subluxing in the palmar and ulnar directions during wrist circumduction. Several methods of intervention exist, but controversy remains on how to best treat this condition. Differential Diagnosis: Distal ulnar fracture, ulnar collateral ligament sprain, triangular fibrocartilage complex lesion, lunotriquetral instability, distal radioulnar joint injury, pisotriquetral joint injury, ECU tendinopathy or subluxation. Treatment: The wrist was placed in a short-arm cast in slight extension and radial deviation for 4 weeks. At that time, the patient was still able to actively sublux the ECU tendon, so a long-arm cast was applied with the wrist in slight extension, radial deviation, and pronation for an additional 4 weeks. The ECU tendon was then found to be stable. She wore a rigid wrist brace for 3 more weeks while she pursued rehabilitation. At the final follow-up appointment, the ECU tendon remained stable, and the wrist was asymptomatic. Uniqueness: Subluxations of the ECU are rare. If the patient does not improve with conservative measures, surgical intervention is warranted to repair the sixth dorsal compartment. Conclusions: A long-arm cast with the elbow flexed to 90° and the wrist in approximately 30° of extension, radial deviation, and pronation was appropriate treatment for this type of injury.


2017 ◽  
Vol 826 ◽  
pp. 396-420 ◽  
Author(s):  
M. Bouyges ◽  
F. Chedevergne ◽  
G. Casalis ◽  
J. Majdalani

This work introduces a similarity solution to the problem of a viscous, incompressible and rotational fluid in a right-cylindrical chamber with uniformly porous walls and a non-circular cross-section. The attendant idealization may be used to model the non-reactive internal flow field of a solid rocket motor with a star-shaped grain configuration. By mapping the radial domain to a circular pipe flow, the Navier–Stokes equations are converted to a fourth-order differential equation that is reminiscent of Berman’s classic expression. Then assuming a small radial deviation from a fixed chamber radius, asymptotic expansions of the three-component velocity and pressure fields are systematically pursued to the second order in the radial deviation amplitude. This enables us to derive a set of ordinary differential relations that can be readily solved for the mean flow variables. In the process of characterizing the ensuing flow motion, the axial, radial and tangential velocities are compared and shown to agree favourably with the simulation results of a finite-volume Navier–Stokes solver at different cross-flow Reynolds numbers, deviation amplitudes and circular wavenumbers.


2020 ◽  
Vol 46 (1) ◽  
pp. 14-20
Author(s):  
Marybeth Ezaki

For centuries, various techniques have been described to stabilize the carpus on the ulna in radial dysplasia to achieve a straight wrist, in the belief that it is better for function and cosmesis. Apart from ulnocarpal fusion, none had succeeded in preventing recurrence of radial deviation. Ulnocarpal fusion, however, carries the risk of shortening an already shortened forearm by damaging the epiphysis. Fingers are often stiff in radial dysplasia, and therefore a straight wrist may actually limit function. Formal assessment of the appearance in operated versus unoperated wrists remain inconclusive. This article challenges the dogma that a straight wrist should be the ideal goal in radial dysplasia. The optimum management of this condition remains debatable.


Hand ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. 464-468 ◽  
Author(s):  
Richard M. Hinds ◽  
Eitan Melamed ◽  
April O’Connell ◽  
Francoise Cherry ◽  
Monica Seu ◽  
...  

Background: There is poor consensus in the literature regarding associated functional limitation and the preferred wrist position for total wrist arthrodesis. The purpose of the current investigation was twofold: (1) to assess the functional limitations of wrist arthrodesis and (2) to determine the optimal position for wrist arthrodesis using a simulated wrist fusion model. Methods: Twenty healthy volunteers underwent simulated wrist arthrodesis in 6 different positions using custom-molded wrist splints: 15° extension with 0° radio-ulnar deviation, 15° extension with 10° ulnar deviation, 15° extension with 10° radial deviation, 0° extension with 0° radio-ulnar deviation, 0° extension with 10° ulnar deviation, and 0° extension with 10° radial deviation. Each volunteer was independently assessed for wrist function using the Jebsen-Taylor hand function test, grip strength, and satisfaction in the simulated wrist fusion positions. Comparisons between all simulated fusion wrists and the baseline unsplinted wrist as well as among the 6 simulated fusion positions were performed. Results: Turning over a card (5.1 vs 4.3 seconds), picking up small objects (7.1 vs 5.8 seconds), and simulated feeding (8.3 vs 7.1 seconds) as well as total Jebsen-Taylor test duration (41.8 vs 37.9 seconds) was significantly longer in simulated fusion wrists. Both grip strength (55.9 vs 80.7 kg) and satisfaction scores (6.4 vs 9.6) were lower in simulated fusion wrists. Wrists in 0° extension also demonstrated significantly shorter durations in stacking checkers than wrists in 15° extension. Conclusion: Our findings suggest that wrist arthrodesis may only compromise select wrist functions. Among the tested wrist fusion positions, wrists fused in neutral may demonstrate better function than wrist fused in slight extension. However, grip strength and satisfaction seem to be unaffected by wrist fusion position.


2014 ◽  
Vol 40 (5) ◽  
pp. 450-457 ◽  
Author(s):  
B. M. Saltzman ◽  
J. M. Frank ◽  
W. Slikker ◽  
J. J. Fernandez ◽  
M. S. Cohen ◽  
...  

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I–III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate. Level of evidence: Level III (Level I-III studies), Systematic Review. Therapeutic.


1992 ◽  
Vol 17 (4) ◽  
pp. 476-478 ◽  
Author(s):  
B. G. ELLIOTT

Abductor pollicis longus, long regarded as a motor for the thumb, is anatomically and functionally a radial deviator of the wrist and should be so named. The abductor carpi is proposed. If the other radial deviators of the wrist are acting this tendon can be selectively utilized as a transfer without loss of function. Reflex spasm of this muscle probably plays an important role in the radial deviation deformity seen in the rheumatoid hand.


Sign in / Sign up

Export Citation Format

Share Document