Non-Invasive Shock Therapy as Effective as Screw Fixation in Treating Nonunion of Proximal Fifth Metatarsal Metaphysial-Diaphyseal Fractures
The severity of a fractured (broken) metatarsal (toe) depends on how and where the bone was broken. The metaphyseal part of the bone is the wider part of the bone, next to the end of the long bone. The diaphyseal part is the shaft of the long bone. The fifth metatarsal is the bone that runs from the center of your foot to the little toe. There are three distinct types of fractures that can happen to the fifth metatarsal, but each of them has challenges in healing properly. Reports of nonunion rates range from 7 percent to 44 percent. Treatment ranges from nonsurgical, using casting and non-weight-bearing to surgery. Nonsurgical procedures do not offer consistent good outcomes and can result in nonunion of the bones and/or chronic pain. For this reason, most surgeons recommend surgery to insert wires, bone grafts, or screws, or a combination of these.

The surgery outcomes are fairly successful, but there have also been reports of complications, particularly with the screws, the intramedullary screw fixation. Because of the movement of the bones, healing may not occur (nonunion), the screw may break through the bone, or there may be lasting chronic pain at the fracture site.

As research continues looking for better treatments, one such treatment for this problem is shock wave therapy for fractures that have not healed. Although researchers don't yet understand how the shock wave therapy works, they have found that the therapy helps the bone to heal and stimulate bone cell growth. The treatment is appealing because it is not invasive, as is surgery, and it is quite safe. On the other hand, the negatives include how available it is and how variable treatment could be. The authors of this article undertook a study to determine if shock wave therapy was a safe, effective technique for treating nonunions of the proximal part of the fifth metatarsal, the part closest to the foot.

Researchers recruited 43 patients with fractured nonunion of the fifth metatarsal. Twenty-three patients (13 males) received high-energy shock wave therapy (2,000 to 4,000 shocks). The patients ranged in age from 17 to 78 years. Two patients smoked regularly and one had diabetes. The time since the original injury ranged from six to 39 months. The other 20 patients (eight men) were treated with surgery, insertion of screws. They ranged in age from 19 to 78 years, and as with the other group, two patients smoked and one had diabetes.

Both procedures were done under general anesthesia. After the shock therapy treatment, the feet were examined for swelling, hematoma (gathering of blood in one area) and ecchymosis (bruising). A weight-bearing cast was then applied and the patients were discharged the following day. The cast was to remain on for four to six weeks. When the patients went for follow-up, the researchers assessed progress with x-rays.

For patients in the surgery group, they were given a splint for their foot and were not allowed to do any weight bearing for two weeks following the surgery. After the two weeks, the patients were assessed, the skin staples or sutures were removed, and the patient was given a hard-soled shoe or walking boot. With these, the patients were allowed to begin toe-touch weight bearing (not bringing the heal down when stepping) and moving on to regular weight bearing, slowly over the course of four to six weeks.

In comparing the healing between the two groups, the researchers found that 20 of the 23 patients in the shock group and 18 of the 20 patients in the surgery group had healed within three months of their procedure. One of the patients in the shock group that had not healed by three months, did heal by six months. One of the two remaining nonhealing shock patients went for another shock treatment six months of the first treatment and healed within a month. Only one complication was reported. One patient experienced petechiae, tiny red and purple spots on the skin, that came and went within 24 hours of treatment.

For the nonhealing patients in the surgery group, they still had not healed by six months after the procedure. One patient underwent surgery again to remove the screw, due to constant pain,. He was then put into a cast and healed after two months. The other patient who hadn't healed experienced a skin infection cellulitis that resolved on its own. The patient also underwent another surgery to remove the screw that was causing pain, but he did not heal after four weeks of using a hard-sole shoe. In all, nine patients in this group experienced 11 complications: the two mentioned plus the one with cellulitis. Seven patients had impingement (pressing) of the screw against the bone and had to have them removed. One other patient broke the same bone a year after the procedure, which was treated successfully with splinting in a walking boot.

There were three athletes in the shock treatment group and all returned to playing soccer after about three months following treatment. Among the athletes in the surgery group, one college soccer player returned to recreational soccer after six months, a recreational soccer player returned to the same level of play, also after six months. A jogger and basketball player were able to resume their previous level of activity after about four months.

The authors wrote that treating with non-weightbearing casts may be a solution but for those patients who are not very active. However, patients who are active need a more aggressive approach. The two treatments, shock therapy and screw fixation are effective for most patients, however screw fixation does have more complications associated with it than does shock therapy.
John P. Furia, MD, et al. Shock Wave Therapy Compared with Intramedullary Screw Fixation for Nonunion of Proximal Fifth Metatarsal Metaphyseal-Diaphyseal Fractures. In The Journal of Bone & Joint Surgery. Feb. 2010. Vol. 92. No. 4. Pp. 846-854.