Today's News

Friday, February 23, 1996

Motorized vs. manual limb lengthening: no difference, says study

Using motorized rather than traditional manual techniques for limb lengthening does not improve the rate of bone healing or reduce complications, according to a study from the University of Maryland Center for Limb Lengthening and Reconstruction at Kernan Hospital in Baltimore presented Friday in poster exhibit B 44. In all of the 70 cases studied, patients used the same type of (Ilizarov) fixator and the bone was lengthened 1 mm per day.

Twenty-seven of the patients used motorized distraction, where a programmable, computer-controlled motor is attached directly to the external fixator. This technique provided a more gradual distraction of 1/1440 mm, 1,440 times per day, compared to the manual distraction used by the other 43 patients. With manual distraction the fixator was turned by the patient 0.25 mm, four times per day.

Although all of the patients had the same rate of bone healing and similar number of complications (one fracture in the motorized group and two fractures in the manual group), it was found that patients over age 20 had longer healing times.

Adam S. Bright, MD, chief resident in the division of orthopaedics, University of Maryland Medical Center (UMMC), and co-author of the study, said that physicians must weigh the benefits of a patient's commitment and ability to use the manual distraction against the increased cost of a motorized fixator - nearly $3,000 - and subject to mechanical breakdown. He added that the motor adds 2.1 pounds to the standard fixator, which generally weighs about 2 pounds.

Co-authors of the study from UMMC are Dr. Bright; Dror Paley, MD, associate professor of orthopaedic surgery, and John E. Herzenberg, MD, associate professor of orthopaedic surgery and pediatrics, who also are co-directors of the Maryland Center for Limb Lengthening and Reconstruction; and Charles Suter, PhD, assistant professor, department of orthopaedic surgery. Ian Weiner, MD, a practicing orthopaedic surgeon in Baltimore, also co-authored the study.

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Last modified 27/September/1996