November 2012

Can Midfoot Nerve Blocks Get Hallux Valgus Patients Back On Their Feet Quicker?

By Brian McCurdy, Senior Editor

In order to address possible pain after hallux valgus surgery, surgeons have used sciatic nerve blocks for anesthesia and post-op analgesics. However, a new study in the French journal Annales Françaises d’Anesthésie et de Réanimation notes that in a percutaneous approach to bunion surgery, a midfoot block may promote quicker postoperative ambulation.

   Researchers randomly assigned 40 patients, who were scheduled to have ambulatory percutaneous hallux valgus repair, to receive either foot infiltration via a midfoot block or a sciatic nerve block. Each block was 30 mL of ropivacaine 7.5%. Surgery occurred without sedation or additional analgesia. The study authors note that both groups received oral paracetamol/codeine and ketoprofene, and took tramadol if necessary. Researchers assessed their walking ability and pain scores for 48 postoperative hours.

   Researchers found pain scores were comparable in each group at rest and while walking, although the time to ambulation without assistance was significantly lower for patients in the midfoot block group at 3.8 ± 1.4 hours in comparison to 19.2 ± 9.5 hours for the sciatic nerve block group. The study authors argued that midfoot blocks were preferable due to the quicker ambulation.

   For post-op analgesia after hallux valgus surgery, Andrew Rice, DPM, prefers a preemptive Mayo block of the midfoot with local anesthesia, which he often combines with sedation. Additionally, he will frequently provide a block of the midfoot or Mayo block at the completion of surgery, prior to bandaging, with long acting bupivacaine 0.5%. Similarly, Jesse Burks, DPM, will use a Mayo-type block for a distal or shaft osteotomy. He will employ more of a localized block for a proximal osteotomy or a Lapidus procedure, but will typically employ a true ankle block as well.

   Dr. Burks has used a sciatic block but does not use it routinely. He has found that a more proximal block will usually extend the “pain-free” period but has the disadvantage of limiting post-op ambulation. Usually, Dr. Burks takes advantage of this if he plans on admitting the patient following surgery, usually when the patient is having more extensive procedures than an isolated bunion correction. Dr. Rice does not use a sciatic block for patients undergoing bunion procedures. A midfoot or Mayo block of the first metatarsal and toe would be effective for patients having percutaneous hallux valgus repair, according to Dr. Rice, an Assistant Clinical Professor in the Department of Orthopaedics and Rehabilitation at the Yale University School of Medicine.

   Dr. Burks agrees. “Anytime a patient retains mobility — as soon after surgery as possible — it just seems his or her post-op recovery is easier,” says Dr. Burks, a Fellow of the American College of Foot and Ankle Surgeons who practices in Little Rock, Ark.

Can Cherries Lower The Risk Of Gout Attacks?

By Danielle Chicano, Editorial Associate

A new study in Arthritis & Rheumatism found that patients with gout who consumed cherries or cherry extract over a two-day period showed a 35 percent lower risk of gout attacks in comparison to those who did not eat the fruit.

   The study focused on 633 patients with gout, 35 percent of whom ate fresh cherries, 5 percent of whom consumed both cherry fruit and cherry extract, and 2 percent of whom consumed only cherry extract. Study authors note that a cherry serving equaled one-half cup or approximately 10 to 12 cherries. According to the results of the study, gout flare risk continued to decrease with increasing cherry consumption up to three servings over two days. The study authors note that further cherry intake beyond three servings over two days did not provide additional benefits to the patient. Additionally, they reported the risk of gout flares was 75 percent lower when the patients combined cherry intake with the uric-acid reducing drug allopurinol.

   Nathan Wei, MD, a rheumatologist, sees approximately 30 to 40 patients a month with gout and recommends cherries to his patients.

   “Many patients already are using (cherries) on their own. There is no harm in trying it. I’m not sure of the effectiveness long-term,” explains Dr. Wei, a Fellow of the American College of Physicians and the American College of Rheumatology.

   William Fishco, DPM, FACFAS, does not specifically recommend eating cherries to reduce gout attacks although he notes he may consider it. Patients should reduce high protein foods, particularly red meats, beans and seafood, as well as beer and sugary drinks to decrease their uric acid levels, notes Dr. Fishco, who is in private practice in Anthem, Az.

   “I certainly think more research will be done on cherries or other food products to prevent gout,” adds Dr. Fishco, a faculty member of the Podiatry Institute. “Pharmaceutical companies will be first in line to develop a ‘cherry pill’ as patients (consumers) would feel more comfortable taking a ‘food’ drug versus traditional drugs like allopurinol.”

   Dr. Wei encourages further studies researching cherries and other food products to lower uric acid for patients with gout, noting it may allow patients to take lower doses of medication. He recommends avoiding high-purine foods and increasing the intake of omega-3s from foods such as fish to combat gout attacks.

   “The acute attacks can be managed with either colchicines in low doses, glucocorticoids or non-steroidal anti-inflammatory drugs (NSAIDs),” explains Dr. Wei. “The more difficult problem is long-term treatment of the hyperuricemia. For this, we can use allopurinol, probenecid, febuxostat (Uloric, Takeda Pharmaceuticals) or pegloticase (Krystexxa, Savient Pharmaceuticals) (if patients have severe tophaceous gout).”

How Accurate Is The Probe-To-Bone Test For Osteomyelitis?

By Brian McCurdy, Senior Editor

A recent study in the Journal of the American Podiatric Medical Association assesses how well the probe-to-bone test can detect lower extremity osteomyelitis in patients with diabetes.

   The study focused on 65 patients, 39 of whom had osteomyelitis. The study says probe-to-bone tests were positive in 30 patients. The positive predictive value for the probe-to-bone test was 87 percent but the negative predictive value was 62 percent. The sensitivity and specificity of the test were 66 percent and 84 percent respectively, according to the authors.

   In the big picture, James Wrobel, DPM, sees the probe-to-bone test as a “good, widely available test” for the clinic, although he notes that the effectiveness of the test can vary in different conditions.

   For example, since osteomyelitis is less prevalent under standard outpatient conditions, the positive predictive value is not as good as it may be with infected inpatients in whom osteomyelitis is three times more prevalent, according to Dr. Wrobel, an Associate Professor of Internal Medicine with the University of Michigan Health System.

   Likewise, for Khurram Khan, DPM, the accuracy of probe to bone depends on patient selection and "a little bit of common sense" as all the studies on probe to bone reveal a pattern. In studies performed on patients with infected wounds, he notes the positive predictive value of the probe to bone tests reaches the high 80s/low 90s percent range. In wounds that are uninfected the positive predictive value is approximately high 50s, but the negative predictive value was high 90s so in infected wounds, the test is highly sensitive and specific, notes Dr. Khan, an Associate Professor in the Division of Medical Sciences at the New York College of Podiatric Medicine.

   In non-infected wounds, Dr. Khan notes if one cannot touch bone, then less likely the patient has osteomyelitis but if one can touch bone, he recommends following up with another study. The bottom line, he says, is one should utilize the probe to bone because it’s quick easy and does not cost anything. However, he cautions that the test is not the gold standard and one needs to add it to the rest of the history and physical to reach a diagnosis, possibly supplementing probe to bone with another exam to confirm diagnosis.

   Under outpatient conditions, Dr. Wrobel says clinical prediction rules can help make up for clinicians’ inaccuracy. He notes magnetic resonance imaging “is still one of the best tests” for ruling out osteomyelitis while a bone culture is a good guide for medical management.

   As for alternatives to probe to bone, long duration of the wound, wounds larger than 2x2 cm with significant depth and erythrocyte sedimentation rate of >65-70 can be a good predictor of osteomyelitis, notes Dr. Khan. He says diagnostic bone biopsy for both culture and histopathology is still the gold standard with MRI being the favored non-invasive exam. If MRI not available, he suggests a white blood cell labeled bone scan is the second best test based on 2012 Infectious Diseases Society of America (ISDA) guidelines.

   "Understand that there is no single feature or physical exam finding or study which reliably excludes osteomyelitis. All of these are to be used together to help you reach a diagnosis," says Dr. Khan.

   Dr. Wrobel also cites a study by Erdman and colleagues in Diabetes Care (http://tinyurl.com/c9tq5dn ) as “one of a few with a retrospective level of evidence for guiding medical management of deep infections.” In the that study, Wrobel notes that patients with intermediate composite severity index scores from 99mTc-WBC SPECT/CT hybrid imaging received six weeks of antibiotics and had a twofold better outcome than those not treated for this long regardless of bone involvement.

   "Sometimes we focus so much on making the osteomyelitis diagnosis that we miss aggressively treating as deep infections," says Dr. Wrobel, which he says is supported by Lavery’s work validating the IDSA classification. He would like to see prospective studies from work using 99mTc-WBC SPECT/CT hybrid imaging.

In Brief

The three Precision Intricast books on lower extremity biomechanics, authored by Kevin Kirby, DPM, are now available in Spanish. They are collections of Precision Intricast newsletters entitled Biomecánica del Pie y la Extremidad Inferior. For more information, visit http://www.dpmlab.com/html/bookreview.html .

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