Researchers Offer Closer Look At Complications In Patients With Diabetes

Two abstracts, which will be presented at the upcoming Symposium on Advanced Wound Care (SAWC), seek to address the impact of dialysis upon diabetic wound healing and the long-term mortality rates of those who undergo non-traumatic amputation.
For the one abstract’s retrospective review, researchers evaluated 150 patients with diabetes on hemodialysis. These patients had 30 months of follow-up for foot ulcers, infections, amputations and death. The abstract authors sought to determine if the patients received “standard preventative care” consistent with patient education, therapeutic shoes and foot care, and whether the preventative care had an impact.
The researchers note that the annual incidence of ulceration was 19.5 percent, the incidence of amputation was 11.6 percent and the incidence of death was 21 percent. Furthermore, only 1 percent of the population received diabetic education, 7 percent received therapeutic shoes or insoles, and 50 percent received foot care, according to the abstract. Researchers note no difference in foot complications among the patients who received preventive care.
However, the study notes that the incidence of foot complications was much higher among diabetic patients on hemodialysis in comparison to patients with diabetes who did not have renal disease. Only a small proportion of the population received preventive services during the 30-month evaluation period.
Abstract lead author Lawrence Lavery, DPM, calls the study results preliminary and says more research is needed. For example, he notes that in many populations, podiatry visits are predictive of amputations since DPMs see high-risk patients with wounds very frequently and 20 percent of people with ulcers have amputations.
“It is like identifying that if a cardiologist sees you, there is an increased risk of dying from a myocardial infarction,” says Dr. Lavery, a Professor in the Department of Surgery at Texas A&M Health Science Center College of Medicine.
Dr. Lavery also notes that approximately 50 percent or more of patients with diabetes on hemodialysis have peripheral vascular disease (PVD) in comparison to 12 percent of a general population of diabetes patients with PVD. Dr. Lavery says many patients with diabetes and PVD on hemodialysis may not be able to achieve wound healing or the prevention of such wounds unless they receive a bypass.

Exploring The Link Between Long-Term Mortality Rates And Amputation
In a second SAWC abstract, researchers reviewed 1,043 charts of diabetic patients who had undergone non-traumatic amputations in six metropolitan areas in Texas in 1993. They then used the Social Security Death Index to identify the mortality data for those patients in 2007.
The abstract found overall mortality at three, five and 10 years was 38.5 percent, 52.3 percent and 75.9 percent respectively. Dialysis patients had a consistently higher mortality rate in comparison to those with chronic renal insufficiency (CRI) or without renal disease despite associated comorbidities, according to the abstract.
Furthermore, the abstract notes that dialysis patients had a significantly higher risk of undergoing a higher level amputation. The abstract researchers say the significant risk factors for mortality are amputation level, dialysis and age. Dr. Lavery adds that patients on dialysis have more severe lower extremity disease, have a longer incidence of diabetes, have more comorbidities and have a poor survival rate. Accordingly, the study authors say there is a significant need for wound care and amputation prevention in diabetic patients on hemodialysis.

The Symposium on Advanced Wound Care will be held from April 24 to 27 at the San Diego Convention Center in San Diego. For more info, go to www.sawc.net.

Study Explores Allograft Potential In Tendon Repair
By Brian McCurdy, Senior Editor
Do freeze-dried tendon allografts have the potential to help reduce tendon adhesions in tendon construction?
A new study in Molecular Therapy explores this question. With the use of a mouse model, researchers compared the use of implanting a 3 mm intercalary live autograft versus a freeze-dried autograft in a distal flexor digitorum longus (FDL). They also identified growth and differentiation factor 5 (Gdf5) as a therapeutic target.
The authors say the study results demonstrate that therapeutic tendon allograft processing is feasible and effective in the realm of tissue engineering to address difficult clinical problems including tendon adhesions.
William Fishco, DPM, occasionally uses fresh-frozen tendon allografts. He will typically use tibialis anterior tendons or peroneus longus tendons. Dr. Fishco notes he will generally use a tendon allograft if there is a large defect as in a rupture of the tibialis anterior tendon (where the tendon stump will retract to the ankle). For small tendon defects and/or for reinforcement of tendon repair, Dr. Fishco normally uses a collagen-based product like Pegasus (equine pericardium).

Assessing The Pros And Cons Of Allografts
Dr. Fishco, a Fellow of the American College of Foot and Ankle Surgeons, cites several advantages of allografts. First of all, Dr. Fishco says one is using tendon to repair tendon. He emphasizes the allograft’s strength of repair and the ability to span large distances, meaning one can repair an old tendon rupture with significant retraction. In addition, Dr. Fishco says there is minimal chance of rejection or transmitting disease since the allograft tissue is relatively avascular, and the repair is more anatomic and natural in comparison to other implantable material. On the other hand, the disadvantages include allograft cost, their limited supply and the chance of disease transmission, which he concedes is still minimal to none.
Dr. Fishco notes the rarity of a rupture of the flexor digitorum or hallucis longus. He says the Achilles and tibialis posterior are the most common flexor tendons to rupture.
In regard to acute Achilles ruptures, Dr. Fishco performs an end to end repair and a gastrocnemius recession if he needs more length. For augmentation, he also may utilize a bioimplant of collagen material. For tibialis posterior tendon ruptures, Dr. Fishco generally performs a gastrocnemius recession to remove the equinus component and repairs the tendon end to end. As he notes, the tibialis posterior tendon generally does not fare well with primary repair. Accordingly, Dr. Fishco says surgeons may need to augment this procedure with a flexor digitorum longus transfer (side to side apposition).
In his practice, Dr. Fishco usually uses an allograft with peroneal tendon ruptures (which are uncommon) and tibialis anterior tendon ruptures.

Are Minor Injuries A Risk Factor For DVT?
By Brian McCurdy, Senior Editor

A recent study in the Archives of Internal Medicine sees a connection between minor injuries and a higher risk of deep vein thrombosis (DVT).
Researchers examined consecutive patients who had their first DVT of the leg or pulmonary embolism, and also looked at control patients. Out of 2,471 DVT patients, 11.7 percent had a minor injury in the three months preceding venous thrombosis, and of 3,534 control patients, 4.4 percent had similar injuries in the time before completing a questionnaire. Minor injuries included sural muscle ruptures and ankle sprains.
Researchers concluded that venous thrombosis was associated with previous minor injury and the association was strongest for injuries that occurred in the four weeks preceding thrombosis and was not apparent before 10 weeks. In addition, the study authors noted a stronger association between thrombosis and minor injuries in the leg whereas injuries in other parts of the body were not associated with injury.
Allan Grossman, DPM, says he and colleagues with whom he has consulted have not seen much of an incidence of minor injuries as a factor in DVT. He says the study does not reveal whether patients have risk factors for DVT such as smoking, obesity or birth control use.
Dr. Grossman notes he does not see DVT in patients with minor injuries because such patients immobilize their limbs themselves by not using the affected limb as much as they otherwise would.