Electrical stimulation of articular cartilage regeneration.

The fact that bone is stress electrogenic is well substantiated. Becker and colleagues have proposed that this property is the biological signal that regulates Wolff's law, whereas others have observed osteogenic responses to electrical voltages and currents. Becker and Murray detected electrical control signal characteristics in fractured long bones. The above findings and the work of Smith, which involved the use of galvanic stimulation, led to the use of bimetallic devices in rats by Becker and Spadaro. Amputated rat extremities at the midhumeral level responded to electrochemical stimulation with partial limb regeneration. The regenerates demonstrated distal growth of an epiphysis and growth plate, with evidence of developing articular cartilage (FIGURE 1). It was believed that similar devices might be used to stimulate the regrowth of specific damaged tissues, such as articular cartilage. When joint surfaces are damaged in mammals, the common repair response is to fill the defect with fibrocartilage. Some authors have reported limited attempts at repair by proliferation of surviving articular cartilage cells and by metaplasia of marrow elements. The increased biochemical activity of hyaline cartilage cells subjected to arthritic changes and the proliferation of hyaline cartilage cells in vitro support the latter observations. It seemed reasonable, therefore, to attempt to stimulate the repair tissue that responds to articular cartilage defects by electrochemical means. This communication describes preliminary results of attempts at the stimulation of articular cartilage repair by electrical means.