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Biomedical subjects

L D Ketchum

Publications and source records attributed to L D Ketchum.

12 recordsLinked to original sources
PubMed1991

The use of the full thickness skin graft in Dupuytren's contracture.

For those hand surgeons who have experienced early complications associated with limited fasciectomies (those who have not, have not done enough limited fasciectomies) and are frustrated by a high rate of recurrence or extension of the disease, incision of the cord and interposition of a full thickness graft is a technique to seriously consider. The procedure is not difficult to perform, but patience and attention to detail are prerequisites for success. That success is measured by complete or near complete release of the contracture with a minimum of morbidity, a nil recurrence rate, and extension rate of less than 10%. This technique is indicated for patients who have one or more elements of the Dupuytren's diathesis. Usually people older than 65 who develop Dupuytren's contracture do not have the diathesis, and their disease can be managed by limited fasciectomy and Z plasty skin lengthening. Finally, Dupuytren's disease presenting with no contracture can be managed effectively and conservatively by a series of intralesional injections of triamcinolone into the nodules and cords, the treatment of choice for all plantar nodules and knuckle pads.

Dupuytren Contracture↗
PubMed1979

Follow-up report on the electrically driven hand splint.

Since the electrically driven hand splint was introduced in 1972, significant improvements have been made in the design and fabrication of the unit which have made it safer, easier to apply, and readily adjustable to the range of motion of a given finger. Over the last 12 months the results of this form of passive exercise were studied by comparing the gain in total active and passive motion in stiff fingers exercised over a 1 month period with similar stiff fingers treated by conventional manual passive joint exercise. There was a significant improvement in the mean gain of both total active and passive motion in those fingers treated with the electrically driven splint.

Biomedical Engineering↗
PubMed1978

A clinical study of forces generated by the intrinsic muscles of the index finger and the extrinsic flexor and extensor muscles of the hand.

A study of the forces generated by the intrinsic muscles of the index finger and coordinating muscles of the hand found that the intrinsic muscles of the index finger contributed combined forces equivalent to approximately 80% of those generated by the flexor profundus and superficialis, and to 73% of the moment for the motion of metacarpopalangeal flexion with simultaneous interphalangeal joint extension. No current tendon transfer operation can correct this deficit, though several supply sufficient force at the metacarpophalangeal joint to counterbalance the extrinsic extensors.

Fingers↗
PubMed1978

The determination of moments for extension of the wrist generated by muscles of the forearm.

In deciding on suitable tendon transfers to replace denervated muscle-tendon units, important considerations are the strength and effectiveness of possible substitutes. A method is presented by which the strength of the wrist extensor muscles and their moment arms can be determined. The method can be applied to other muscles at other joints. It involves the use of a force transducer which measures the combined forces of the three wrist extensors in an isometric contraction. This moment for wrist extension, measured in the living intact arm, is the same as the sum of the moments of the three wrist extensor muscles. The contribution of each muscle to the total moment is calculated from ratios that have been developed from a quantitative study of moment arms and muscle masses in sixteen cadaver limbs. It is suggested that the ratio of one moment arm to another is fairly constant from subject to subject, and that muscle masses also have sufficiently similar ratios to each other to serve as the basis for practical estimations by the surgeon. Thus the surgeon needs only one or two direct measurements of moments externally and only one or two skeletal measurements on any living subject to be able to estimate the effectiveness of a number of muscles on the basis of cadaver studies such as this, and to project the behavior of a muscle after it has been transferred to a position where it will have new moment arms.

Biomechanical Phenomena↗
PubMed1978

Pharmacological alterations in the clotting mechanism: use in microvascular surgery.

At the present time there is confusion as to what pharmacological adjuncts are helpful toward increasing patency rates of microvascular repairs. To select a drug rationally, an understanding of the clotting mechanism in small vessels is essential so that agents may be selected that alone or in combination will react with the elements of the blood and will allow for continued perfusion without risk of hemorrhage or toxicity. Drugs which are Federal Drug Aministration approved and currently available are drugs having nonspecific effects involving more than one aspect of the clotting mechanism; they often in undesirable as well as desirable effects. Further development will result in the use of more selective and sophisticated agents. Presently it would appear desirable to employ agents to (1) increase blood flow and decrease blood viscosity, such as dextran 70; (2) decrease platelet functions, such as aspirin-type drugs; (3) mitigate against the actions of thrombin on platelets and fibrinogen using low-dose heparin; (4) reduce anxiety and vasospasm using chlorpromazine or Thorazine.

Animals↗
PubMed1977

Primary tendon healing: a review.

Clinical and experimental studies on primary tendon healing are reviewed and correlated. Emphasis is placed on the importance of blending the extratendinous and intratendinous elements of tendon healing to obtain optimal functional results. Studies which demonstrate the ability of tendon cells to metabolize, proliferate, and secrete collagen when isolated from paratendinous tissue are cited along with those which demonstrate the importance of the microcirculation of the tendon in tendon healing. Those factors which interfere with intratendinous healing are discussed, such as invasive suture techniques, tension on the area of repair, and interference with segmental blood supply within zone II. The importance of the synovial sheath and synovial fluid in nourishing tendon cells and the effect of ischemia in stimulating the ingrowth of adhesions are brought out. Discussion includes such factors involved in the postoperative management of tendon repairs as those which affect the strength of tendon repairs and quantitative and qualitative methods of modifying adhesion formation.

Adult↗
PubMed1977

Hypertrophic scars and keloids.

By modifying the wound healing process, it is possible to deal effectively with most abnormal forms of scarring, through perhaps 15 per cent of these lesions cannot be managed to the satisfaction of surgeon and patient. A laboratory test to determine which patients will overrespond to the stimulus of wounding and a better understanding of why these patients have an inordinately high anabolic rate of collagen metabolism will help in the salvage of those patients who are yet unmanageable. The great majority of patients can be helped and with them the lesions are best managed prophylactically if possible and if not the established lesion is dealt with. In preventing such lesions at the time of surgery, in addition to the strict adherence to basic surgical principles, every effort should be taken to relieve the wound of tension; that is, the natural tension produced by the underlying skeleton and tension in the early period of wound healing when the wound is weak and vulnerable to spreading. The inflammatory phase of wound healing can be modified pharmacologically with anti-inflammatory agents, fibroblast reproduction can be suppressed with radiotherapy, and collagen bundles can be reoriented with pressure. One or all of these modalities are applicable to appropriate lesions. In the established hypertrophic scar or keloid, lesions of resonable size on the trunk can be treated with intralesional injections of triamcinolone only; lesions larger than 75 sq cm or facial lesions can be excised and closed or shaved and grafted, again with one or all of the above mentioned modalities being the control factor that modifies healing and prevents recurrence.

Cicatrix↗