Patients who are interested in participation will be included in the study and divided by randomization into two groups of equal size. The first group is treated with ESWT in combination with regular guideline treatment. The second group is set up as control group and will only receive regular guideline treatment. The participants are examined in different ways to evaluate whether ESWT helps the healing of foot ulcers. The investigators want to measure tissue oxygen pressure and foot sense of touch. The foot ulcers are inspected for infection at every consultation, and a swab sample will be collected at enrollment. The size of the ulcers are measured and photographed each time. The investigators will count how many foot ulcers that are completely healed during the test period and measure the sizes of the remaining foot ulcers. The patients are asked to evaluate pain related to the foot ulcer. Data concerning participants' co morbidities and use of analgesic drugs are obtained from the patient journal and by patient interview.