News and Trends

Study Suggests Benefit Of Conservative Surgery For Diabetic Foot Osteomyelitis

Could conservative surgery have an impact in treating osteomyelitis in the diabetic foot? A recent study published in Diabetologia found that surgery without amputation was successful in nearly half of the patients with diabetic foot osteomyelitis.

   In the study, researchers assessed 185 consecutive patients with diabetic foot osteomyelitis and histopathological confirmation of bone involvement. Histopathological analysis revealed that 50.8 percent of patients had acute osteomyelitis, 23.2 percent had chronic osteomyelitis and 24.3 percent had acute exacerbation of chronic osteomyelitis. Furthermore, researchers isolated Staphylococcus aureus in the cultures of 51.3 percent of the patients and 35 of these patients had methicillin-resistant Staph aureus (MRSA).

   As the study notes, over 49 percent of patients received conservative surgery, which did not consist of amputation, over 42 percent of patients underwent minor foot amputations and 8 percent had major amputations. Five patients died in the perioperative period, according to the study.

   For the 91 patients who underwent conservative surgical procedures (without local or high-level amputation), researchers found that nearly half of these patients had a successful result. The study authors did note that the risks of conservative surgery for diabetic foot osteomyelitis include exposed bone, ischemia and necrotizing soft tissue infection.

Weighing The Pros And Cons Of Different Treatment Options

William Jeffcoate, MD, believes the opinion of osteomyelitis is “changing quite fast” in the United States. He says the traditional advice was to remove all infected and necrotic bone. However, Dr. Jeffcoate says this changed 20 years ago when it became apparent that beta lactams/lactamase combinations and quinolones might be effective. Several studies have shown that non-surgical management of osteomyelitis may arrest infection in about 70 percent of patients, according to Dr. Jeffcoate, who practices in the Foot Ulcer Trials Unit in the Department of Diabetes and Endocrinology at City Hospital in Nottingham, U.K.

   Nicholas Bevilacqua, DPM, says it is difficult to eradicate infection in bone solely with antibiotics as devitalized bone and soft tissue impede healing and provide an ongoing nidus for infection. He says the combination of conservative surgery with antibiotics has the advantage of ensuring that all the infection has been eliminated.

   A potential disadvantage is that conservative surgery carries increased risk and at times may result in amputation, according to Dr. Bevilacqua, an attending surgeon at the Foot and Ankle Clinics and Amputation Prevention Center at Broadlawns Medical Center in Des Moines, Iowa.

   The Infectious Diseases Society of America (IDSA) guidelines list four scenarios in which Dr. Bevilacqua says one might consider non-surgical management of osteomyelitis in the diabetic foot. These scenarios include:

• when there is no acceptable surgical target;

• when the patient has ischemia caused by non-bypassable vascular disease but seeks to avoid amputation;

• when infection is confined to the forefoot and there is minimal soft-tissue loss; and

• when surgical management has excessive risk or is otherwise not appropriate or desirable.

   As far as surgical intervention goes, Dr. Jeffcoate notes there is little data although two recent studies note a high rate of recurrence and the need for more surgery. He cites one surgical series by Henke that noted a 23 percent rate of major amputation in patients who were hospitalized with osteomyelitis.

   “People are beginning to accept that perhaps we do not yet know the best way to manage pedal osteomyelitis. The adverse effects of the treatment need to be taken into account as well as the effectiveness,” emphasizes Dr. Jeffcoate.

   As Dr. Jeffcoate points out, both medical and surgical treatment may result in a deformed foot, which increases the risk of transfer ulcers. He says increased antibiotic use can lead to an increased emergence of resistant strains.

   Dr. Bevilacqua feels that optimal management may be an effective combination of surgery and culture-guided antibiotics. He says further research should focus on determining the correct duration of antibiotic therapy.

What Does The Future Hold For Osteomyelitis Research?

   Dr. Jeffcoate agrees with the study authors on the need for more randomized controlled trials on this subject. He is currently involved with the Diabetes Osteomyelitis Management and Outcome (DOMO) study. Dr. Jeffcoate encourages podiatrists to get involved with this study and note their newly presenting cases of osteomyelitis. (Editor’s note: For more information, visit www.domo.org.uk.)

   The study will determine the actual rates of clinical success and failure of the primary intervention as well as differences in outcome between non-surgical treatment and early surgical excision of infected bone, according to DOMO’s Web site.

   In addition, the study will reportedly determine differences in outcomes from various antibiotics and determine whether the result of treatment correlates with any adjunctive treatments such as hyperbaric oxygen therapy.

   For further reading, see “Current Concepts In Treating Osteomyelitis” in the July 2007 issue.

Could Pneumatic Compression Have Promise For Patients With CLI?

By Brian McCurdy, Senior Editor

A recent study suggests that adjunctive use of intermittent pneumatic compression (IPC) can be of benefit in treating chronic wounds and preventing amputations in patients with critical limb ischemia (CLI).

   In the study, presented as an abstract at the recent Diabetic Limb Salvage conference, researchers compared a control group of 24 patients to a group of 24 patients who received IPC for tissue loss and non-healing foot wounds secondary to chronic critical limb ischemia. The follow-up period was 18 months.

   Researchers found 83 percent of the control group did not heal foot wounds and underwent a below knee amputation. Among those receiving IPC, 14 patients experienced complete wound healing and limb salvage while 10 patients received a below knee amputation after their wounds failed to heal.

   Abstract author Steven J. Kavros, DPM, calls IPC a “tremendous” adjunctive therapy for patients with vascular compromise, especially when all other surgical options have been exhausted. He has published several studies on the subject and has been using the technology for a decade “with great success.” He notes that Medicare recently approved the technology for reimbursement.

   One can successfully use IPC for lower extremity diabetic and vascular ulcers, according to Dr. Kavros, who is affiliated with the Department of Orthopedic Surgery and Gonda Vascular Wound Healing Center at the Mayo Clinic in Rochester, Minn. He notes that the procedure can decrease amputation in the lower extremity.

   Dr. Kavros says the pump helps relieve and control venous edema and increases oxygenated blood flow to the foot. In addition, IPC stimulates increased release of nitric oxide from the vascular endothelium. He says this facilitates increased blood flow and an increase in growth factor release for angiogenesis. He adds that acute deep vein thrombosis is a contraindication to intermittent pneumatic compression therapy.

Study Examines Differences Between Custom And Semi-Custom Orthoses

By Brian McCurdy, Senior Editor

Podiatric physicians have a number of options when choosing orthoses, including custom, prefabricated and semi-custom devices. A recent study in the Journal of the American Podiatric Medical Association examines the differences between custom and semi-custom orthotics.

   Researchers fitted 19 uninjured runners for custom and semi-custom orthoses. Runners underwent gait analysis of running and walking while wearing no orthotics, wearing custom orthotics and wearing semi-custom orthotics.

   The study found that during running and walking, rearfoot eversion was lowest through most of stance with the custom orthotic. Authors reported “no significant differences” in peak eversion among the three groups of runners. When assessing individual responses during running trials, researchers noted that eight of 19 runners demonstrated a 2 degree reduction in peak eversion in the custom orthotic in comparison to runners not wearing orthoses, according to the study. Among those wearing semi-custom devices, the study says only four patients had a greater than 2 degree reduction in peak eversion in comparison to the group that did not wear orthotics and two patients demonstrated an increase.

Do Semi-Custom Orthoses Have Merit?

   Paul Scherer, DPM, says that in walking patients, semi-custom devices decrease eversion more than custom devices. With running patients, he notes that custom devices decrease eversion more than semi-custom devices.

   While he respects the work of lead author Irene Davis, PhD, PT, Dr. Scherer says a flaw in the study is that researchers did not use the Foot Posture Index (FPI). Dr. Scherer notes the FPI is becoming standard in research as it globalizes the foot on a scale of -12 (cavus) to +12 (flat).

   Although more DPMs are using semi-custom orthoses for economic reasons, the profession needs to know more about the effects of the devices, according to Dr. Scherer, the Chairperson of the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt College.

   Douglas Richie Jr., DPM, notes the importance of understanding that a semi-custom orthotic, in comparison to a prefabricated device, is a “very sophisticated,” orthosis generated by a computer and based on stored data from thousands of corrected casts of orthoses.

   Dr. Richie says semi-custom orthoses have the advantage of being cheaper. On the other hand, he notes that custom devices have more accurate arch contours and may be more comfortable. Both devices are similar when it comes to control of rearfoot motion, according to Dr. Richie, an Adjunct Associate Professor in the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt College.

   Although he has used both custom and semi-custom orthoses, Dr. Richie prefers custom devices. He says he has “great confidence” in the accuracy and reproducibility of his neutral suspension casting technique. However, Dr. Richie does say that semi-custom devices can provide better patient outcomes for DPMs who are not confident with their casting methods.

   “There is valid science behind the technology of the semi-custom devices based upon studies of shapes of thousands of corrected positive casts used in the fabrication of custom functional foot orthoses,” says Dr. Richie. “Semi-custom foot orthoses provide devices that may neutralize casting errors which can result from human error or poor technique by the practitioner.”

In Brief

By Brian McCurdy, Senior Editor

Findings from two separate studies presented at the recent New Cardiovascular Horizons (NCVH) conference show that Metanx (PamLab) facilitated improvements in numbness and burning pain associated with diabetic neuropathy, according to PamLab.

   The company notes that one of the studies, which involved 31 patients with diabetes and sensory loss in their feet, showed that Metanx improved feelings of numbness by 38 percent at six months and 80 percent by one year.