This study tests the hypothesis that radial extracorporeal shock wave therapy (rESWT) as performed by Zoech (JATROS Orthop 2009;(1):46-47) is effective and safe in treatment of chronic soft tissue wounds, and is statistically significantly more effective than sham-treatment of chronic soft tissue wounds.

Zoech (2009) treated in a feasibility study a total of n=18 patients affected by 21 ulcers in Stage IA or IIA (according to Armstrong and colleagues, Diabetes Care 1998;21:855-859) with repetitive radial extracorporeal shock wave therapy (rESWT) using the Swiss DolorClast device (Electro Medical Systems S.A., Nyon, Switzerland). The wounds had been observed for more than 6 weeks. In nine cases the wounds were located in non-loaded areas such as the edge of the foot, or appeared after previous toe amputation. In 12 cases the wounds were located on the sole, the toes or the heel; in these cases the average area of the wounds was 351 mm^2 (116 to 599 mm^2). Local wound treatment consisted of regular debridement by scalpel, followed by disinfection with sterile saline solution and application of wet treatment adequate to the stage of the wounds. Depending on the amount of secretion, the depth of the ulcer and the healing stages, different bandage materials were used. Besides this, rESWT was applied at intervals depending on the size and the depth of the ulcers, once or twice a week for three to six weeks, with 1,000 impulses per cm^2 and treatment session with positive energy flux density (EFD) of 0.1 mJ/mm^2. To this end ulcers were covered with sterile drape in order to avoid direct contact of ultrasound jelly and the handpiece of the rESWT device with the ulcers. After further disinfection with sterile saline solution, bandage was applied. The state of the ulcers was documented photographically at regular intervals and the size of the ulcers were evaluated with digital image analysis. Wounds were evaluated after the first, second and third week. Zoech (2009) noted that rESWT caused no pain, and neither local or generalized infections were observed throughout the observation period. Sixteen out of the 21 wounds healed within a mean period of six weeks (range: 3 to 9 weeks). In three cases, sufficient granulation tissue was formed after eight weeks on average, allowing for wound covering by gap tissue transplant. On average the size of the ulcers was reduced to 67% (20-100%) after the first week, 53% (15-90%) after the second week and 35% (9-78%) after the third week compared to baseline. These data indicate that the application of repetitive rESWT using the Swiss DolorClast is a low-effort and effective complement to standard therapy in diabetic foot ulcers without signs of infection or ischemia. In the study by Zoech (2009) patients were specifically very satisfied by the good tolerability and the absence of any significant side effects.

However, Zoech (2009) did not investigate a control group. Accordingly, it is currently unknown whether rESWT as performed by Zoech (2009) is more effective than sham-treatment of chronic soft tissue wounds. The present study was designed to answer this question.

Inclusion Criteria:

• adults (both male and female) with chronic soft tissue wounds
• age range: between 18 and 80 years
• willingness of the patient to participate in the study, and written informed consent signed and personally dated by the patient
• different kinds of chronic soft tissue wounds: diabetic foot ulcers, post traumatic, venous stasis ulcer, decubitus
• wounds scored as Grade/Stage 1A, 1C, 2A and 2C according to Armstrong et al. (Diabetes Care 1998;21:855-859)
• No contraindications for rESWT

Exclusion Criteria:

• children and teenagers below the age of 18
• no willingness of the patient to participate in the study, and/or written informed consent not signed and not personally dated by the patient
• wounds scored as Grade/Stage 0A, 0B, 0C, 0D, 1B, 1D, 2B, 2D, 3A, 3B, 3C or 3D according to Armstrong et al. (1998)
• Burn wounds
• Uncontrolled diabetes because glycaemic control is crucial for wound healing and erratic values will effect the study results
• Blood sugar levels of the patient before meals are NOT regularly higher than 7mmol/L and are NOT regularly higher than 11mmol/L one to two hours after meals)
• Contraindications of rESWT: treatment of (i) soft tissue wounds over air-filled tissue (lung, gut), (ii) pregnant patients, (iii) patients with blood-clotting disorders (including local thrombosis), (iv) patients treated with oral anticoagulations, (v) soft tissue wounds above local tumors, and (vi) patients treated with local corticosteroid applications in the time period of six weeks before the first rESWT session (if applicable).

A medical assistant in the Wound Care Unit, Dept on Internal Medicine, Kuala Lumpur Hospital (Kuala Lumpur, Malaysia) will allocate interventions by means of opaque sealed envelopes that will be marked according to the allocation schedule. The medical assistant will be unaware of the size of the blocks.

The randomized intervention assignment as outlined above will be concealed from both patients and health care staff until recruitment will be complete and irrevocable.

Therapists applying the treatments will not be blinded.

All assessments before the first treatment (baseline) and during the follow-up period (either three months after start of the treatments or until complete epithelialization, respectively) will be performed by assessors blind to the intervention.