Jun-09

Can One-Screw Fixation For Subtalar Joint Fusion Be Effective?

By Brian McCurdy, Senior Editor

   The wide variability of fusion rates for subtalar joint (STJ) arthrodesis has sparked debate about the type, orientation and amount of internal fixation. A recent study suggests the use of one-screw fixation versus two-screw fixation is comparable in regard to nonunion rates for the isolated STJ arthrodesis.

   The study, which was presented as a poster at the American College of Foot and Ankle Surgeons Annual Scientific Meeting, was a retrospective review of 113 patients with isolated STJ fusions. Patients were randomized into groups of one-screw fixation (89 patients) or two-screw fixation (24 patients). The authors determined STJ fusion by clinical signs of no pain or swelling at the surgical site and radiographic trabeculation of recent post-op radiographs. The mean follow-up was 11 months.

   Authors found that 13 single-screw patients experienced nonunion in comparison to six nonunions in two-screw patients. The fusion rate was 85.4 percent in one-screw patients and 75 percent in two-screw patients. Surgeons removed hardware in 20 one-screw patients and in three two-screw patients.

   The authors noted no significant statistical difference between the two fixation groups in regard to nonunion rates, post-op complications and the need for further surgery. While the study authors expected a higher nonunion rate with one screw, they found that the motion that occurs with one screw may not be significant enough to directly impact nonunion rate.

Weighing The Pros And Cons Of One-Screw Fixation

   Study co-author William DeCarbo, DPM, cites cadaver studies that show that two-screw fixation offers increased compression and rotational stability. However, he notes this did not translate into an increased fusion rate in his study.

   Dr. DeCarbo cites several studies showing good results with single-screw fixation for STJ fusion. As he points out, Haskell and colleagues reported a 98 percent fusion rate in 101 patients using one screw with only two nonunions. A study by Easley showed no significant relationship between union rate and the number of screws used. Dr. DeCarbo adds that there are no contraindications to using one screw for STJ fusion.

   Don Green, DPM, has used one screw for STJ fixation. He notes one-screw patients have fared well and they have not experienced any more nonunions or delayed healing in comparison to two-screw patients. Dr. Green says the bone usually heals adequately after three months.

   The two-screw technique does have an advantage in that it reduces rotational motion and it may be necessary in certain patients, such as those who are nonadherent, according to Dr. Green, a Clinical Professor at the California School of Podiatric Medicine at Samuel Merritt University, and a Fellow of the American College of Foot and Ankle Surgeons. However, he says if the patient is very non-adherent, even two screws may not be enough to prevent nonunion.

    “The take home point is good surgical technique is more important than using one or two screws for isolated STJ fusions,” says Dr. DeCarbo, who practices at the Orthopedic Foot and Ankle Center in Columbus, Ohio.

Study: Geometry Of Venous Leg Ulcers May Predict Healing

By Lauren Grant, Editorial Assistant

   A recent study in Wound Repair and Regeneration is reportedly the first to present data that links the geometry of venous leg ulcers (VLUs) with healing time.

   The study focused on 338 VLUs that were treated with either Dermagraft (Advanced Biohealing) or standard care. Researchers observed wound size and shape. The study found that venous leg ulcers that evolved into a more convex shape and had a linear relationship between margin size and surface area were more likely to heal in 12 weeks.

   For the most part, study authors say VLUs that presented with isolated epithelium or with more than one ulcer in an area had a low correlation between surface area and margins. These ulcers had a slower healing time. The study found that only 13 percent of the VLUs with a linear pattern r(2)<.80 completely closed in comparison to 43 percent of the remaining wounds with an r(2)>.80.

   The authors feel the results show that wounds with irregular tendencies and nonlinear relationships may be different than wounds with a linear correlation. The study authors found that a proportional relationship between perimeter and area measurements may correlate to the healing time of the wound.

   Study co-author David Armstrong, DPM, PhD, says the idea for the study came from in-clinic observations.

    “We began to notice, after looking at many hundreds of wounds, that more circular wounds seemed to heal more predictably regardless of size,” explains Dr. Armstrong, a Professor of Surgery and Director of Lower Extremity Research for the Southern Arizona Limb Salvage Alliance (SALSA) at the University of Arizona.

   Dr. Armstrong says more irregularly shaped wounds may prompt a different approach to treatment.

    “If we see an irregular wound, we may be more active in aggressively treating those patients with more advanced modalities,” points out Dr. Armstrong.

Does A New Statin Offer Promise In Preventing VTE?

By Brian McCurdy, Senior Editor

   A recent study in the New England Journal of Medicine (NEJM) says rosuvastatin (Crestor, AstraZeneca) may significantly reduce the incidence of symptomatic venous thromboembolism (VTE).

   The study consisted of 17,802 patients, randomized to receive 20 mg of rosuvastatin per day or a placebo. The patients all had low-density lipoprotein (LDL) cholesterol levels below 130 mg/dL and high-sensitivity C-reactive protein levels of 2 mg/L or higher. The study notes that during an average follow-up of 1.9 years, 94 patients experienced symptomatic VTE (34 in the rosuvastatin group and 60 in the placebo group).

   How common is VTE in the podiatric population? Lee C. Rogers, DPM, cites a recent study in Chest, which notes an 0.4 percent incidence of VTE following podiatric procedures. He notes that this study was limited to forefoot surgery and injections, which have a low probability for deep vein thrombosis (DVT), and would not be applicable to rearfoot or ankle surgeries requiring immobilization. He says the incidence of VTE increases if patients have a history of VTE, oral contraceptive use or obesity. As Dr. Rogers points out, the NEJM study had a “very typical” podiatric population with most of the patients being over the age of 60 and overweight. Dr. Rogers notes that rosuvastatin reduced the rate of DVT nearly twofold in that population.

   However, Dr. Rogers cautions that the study was not designed to advocate the use of statins for prophylaxis in the perioperative period. In this situation, low molecular weight heparins are still the drug of choice, according to Dr. Rogers. The most effective postoperative approach to prevent VTE is the use of low molecular weight heparins along with early mobilization, sequential compression devices and anti-embolic stockings, notes Dr. Rogers, the Director of the Amputation Prevention Center at Broadlawns Medical Center in Des Moines, Iowa.

   Allan Grossman, DPM, believes the NEJM study has “limited usage” in podiatric practice in regard to VTE. He does think statins have a long-term benefit at reducing the incidence of VTE incidence but is unsure if there is a short-term benefit.

   As Dr. Grosssman notes, statins can suppress specific circulating lipoproteins that heighten the risk of VTE. In addition, statins appear to alter portions of elements on the vascular endothelium as well as the coagulation cascade consistent with an antithrombolitic effect, according to Dr. Grossman, a Fellow of the American College of Foot and Ankle Surgeons.

In Brief

   The North American Center for Continuing Medical Education (NACCME) has signed new five-year agreements with the Wound Healing Society (WHS) and the Association for the Advancement of Wound Care (AAWC). The WHS agreement continues the partnership and co-location with the annual Symposium on Advanced Wound Care (SAWC) Spring meeting through 2013. The partnership with the AAWC also includes SAWC/ WHS Spring and extends it to include the SAWC Fall meeting, notes NACCME. The inaugural SAWC Fall will be Sept. 16 to 18 at the Gaylord National Hotel and Convention Center in Washington, DC. For more info, visit www.sawc.net.