The invention relates to apparatus and method for ultrasonically stimulating cartilage growth. The apparatus includes at least one ergonomically constructed ultrasonic transducer configured to cooperate with a placement module or strip for placement in proximity to an area where cartilage growth is desired. The apparatus also utilizes a portable, ergonomically constructed main operating unit constructed to fit within a pouch worn by the patient. In operation, at least one ultrasonic transducer positioned in proximity to an osteochondral site is excited for a predetermined period of time. To ensure that at least one ultrasonic transducer is properly positioned, and to insure compliance with a treatment protocol, a safety interlock is provided to prevent inadvertent excitation of the at least one ultrasonic transducer.