Cath Lab Digest

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.