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Biomedical subjects

L J Askew

Publications and source records attributed to L J Askew.

9 recordsLinked to original sources

Functional ranges of motion of the wrist joint.

We have examined 40 normal subjects (20 men and 20 women) to determine the ideal range of motion required to perform activities of daily living. The amount of wrist flexion and extension, as well as radial and ulnar deviation, was measured simultaneously by means of a biaxial wrist electrogoniometer. The entire battery of evaluated tasks could be achieved with 60 degrees of extension, 54 degrees of flexion, 40 degrees of ulnar deviation, and 17 degrees of radial deviation, which reflects the maximum wrist motion required for daily activities. The majority of the hand placement and range of motion tasks that were studied in this project could be accomplished with 70 percent of the maximal range of wrist motion. This converts to 40 degrees each of wrist flexion and extension, and 40 degrees of combined radial-ulnar deviation. This study provides normal standards for the functional range of motion of the wrist.

Activities of Daily Living

Rupture of the tendon of the long head of the biceps brachii. Surgical versus nonsurgical treatment.

Twenty-seven shoulders (in 26 patients) that had surgical repair of a rupture of the long head of the biceps tendon between 1962 and 1981 were evaluated at three to 22 years after injury (mean, 13 years). Thirty similar patients had been treated nonsurgically and were evaluated two to 15 years (mean, 4.6 years) after tendon rupture. Biomechanical testing was performed on ten patients in the surgical group and 13 in the nonsurgical group. Residual arm pain was infrequent in both surgically and nonsurgically treated groups. Residual subjective weakness at the elbow was reported in four of the surgical group and in 20 of the nonsurgical group. Surgically treated patients returned to work later than nonsurgical patients; however, 11 in the nonsurgical group were not able to return to full work capacity, versus only two in the surgical group. On biomechanical testing, the nonsurgical group had lost a mean of 21% of supination strength and 8% of elbow flexion strength but had no weakness in grip, pronation, or elbow extension. The surgical group had lost no strength in any of these testing modes.

Adult

Strength function after elbow arthroplasty.

A prospective study of elbow strength after total elbow joint arthroplasty was conducted in 27 patients (31 procedures). In this overall group, flexion strength improved 92%, pronation, 63%, and supination, 69%. Grip strength improved 35%, but there was no mean improvement in extension strength among these patients. After 27 procedures for rheumatoid arthritis, the average strength improvement of all five functions was 71% compared to a 25% improvement in four patients with nonrheumatoid involvement. Placement of the prosthetic axis of rotation proximal or anterior to the normal axis was associated with consistently poorer strength. The sample was too small to distinguish performance among prosthetic types, but the triceps-sparing approach showed consistently better strength in extension (averaging 20%) than did the other exposures.

Arthritis

Total arthroplasty of the thumb trapeziometacarpal joint.

Considering the large number of procedures designed for the thumb trapeziometacarpal (TMC) joint, it is evident that none are completely satisfactory. Total arthroplasty attempts to improve the results of resection or space-occupying arthroplasties which, while providing good pain relief, have offered little thumb stability, strength, or normal motion. Conditions of surrounding joints indicate that this disease process is not always a straightforward clinical presentation and that a variety of surgical options are needed. When joint disease is limited to the TMC joint, bone stock is good and there is no excessive heterotopic bone. A total arthroplasty can be considered in selected patients. Careful analysis of comparative series between silicone spacers and tendon spacers for trapezium resection arthroplasty demonstrates that both pinch strength and motion are somewhat less than with total trapezial arthroplasty. Key-type pinch rarely was over 50% of the normal and averaged less than 5 kg for both interposition and silicone arthroplasty. Continued problems with implant subluxation, silicone reactive synovitis, and other complications suggest that these resections (replacement) of the trapezium are not error-free and sacrifice thumb stability. With all types of thumb reconstruction, high precision technique is required. With improved biomaterials, thumb biomechanics, and better fixation techniques, more physiologic implant arthroplasties can be anticipated to improve the current designs of total joint arthroplasties.

Aged

Isometric elbow strength in normal individuals.

Isometric elbow strength was measured with torque cell dynamometers in a group of 104 normal subjects. Their mean age was 43 years (range, 21-79 years). Test functions included elbow flexion and extension, forearm pronation and supination, and grip. In general, the men were twice as strong as the women, and the dominant extremities were 6% stronger than the nondominant. The mean extension strength was 61% of that of flexion, and pronation was 86% of supination.

Adult

Electromyographic analysis of the thumb: a study of isometric forces in pinch and grasp.

An electromyographic study of thumb muscles was performed on eight subjects by means of integrated polyelectromyography and simultaneous recordings of isometric flexion-extension, abduction-adduction, and prehensile pinch and grasp of the thumb. The integrated electromyographic signal proved to be an excellent index of thumb muscle activity, with a linear relationship found at low to middle levels of muscle strength. To facilitate understanding of thumb function, thumb muscles can be classified as primary or secondary on the basis of electrical potential activity. In isometric flexion, the flexor pollicis longus (FPL) was primary, whereas in extension, the extensor pollicis longus (EPL) and abductor pollicis longus were primary. In adduction, the adductor pollicis and EPL were primary and the FPL was secondary. In abduction, the abductor pollicis brevis and opponens pollicis were primary. The adductor pollicis, and FPL were nearly equal during pinch and grasp, with significant electrical activity increasing with greater force requirements. The first dorsal interosseous and EPL contributed secondarily in both pinch and grasp. When surgeons consider tendon transfers for nonfunctioning thumb muscles, the primary muscles should be replaced first to best restore pinch and grasp strength.

Biomechanical Phenomena

Rupture of the distal tendon of the biceps brachii. A biomechanical study.

In biomechanical studies on ten patients who had had a rupture of the distal tendon of the biceps brachii, we compared the results of immediate anatomical reattachment, delayed reattachment, and conservative treatment. When the tendon was simply attached to the brachialis muscle (one patient), there was nearly normal strength in elbow flexion but about 50 per cent loss of forearm supination. Late reinsertion (one patient) improved strength of both flexion and supination, but not to normal. Immediate reattachment (four patients) restored normal strength in flexion and supination at one year but not at four months (one patient). With conservative treatment (three patients) there was a mean loss of 40 per cent of supination strength and variable loss of flexion strength, averaging 30 per cent. These data suggest that immediate surgical reinsertion of the biceps tendon into the radial tuberosity, compared with other modes of treatment, restores more strength of flexion and supination.

Adult