May 2010

In the moment: Footcare

Photo courtesy of Arizona AFO

By Jordana Bieze Foster

PTTD prognostication

Four criteria predict response to bracing

Four variables, identifiable at an initial clinical evaluation, can help predict whether bracing will be successful in patients with posterior tibial tendon dysfunction, according to research from the University of Rochester Medical Center in Rochester, NY.

The investigators retrospectively reviewed records for 166 patients with PTTD, 41 of whom (24.6%) underwent surgery during the six and a half year study period. The median treatment duration for the entire study population was 300 days; 60% of patients in the operative group had surgery fewer than 300 days from initial evaluation.

Patients were more likely to eventually have surgery if at initial evaluation they had a body mass index of less than 30, had previously used an orthotic device, had undergone cortisone injection, or had symptoms for more than six months.

In a logistic regression model, the sensitivity of these four criteria for predicting eventual surgery was low, only 38.2%, but the specificity was high, at 95.4%. This means that the four variables cannot be used to predict which patients will need surgery, but that patients who meet none of the four criteria are very unlikely to have a surgical outcome.

The findings, published in the March issue of Foot & Ankle International, support the use of custom bracing for management of PTTD in patients who have not previously used an orthotic device and fail to meet the other three criteria. Patients in the nonoperative group were significantly more likely than those in the operative group to progress to a “less aggressive” form of bracing (for example, from a custom brace to an over-the-counter brace) during the treatment period. The majority (60%) of those who went on to surgery tended to stay in the brace they were initially prescribed, compared to 46.4% of those in the nonoperative group.

Custom braces were prescribed at initial evaluation to a higher percentage of patients in the operative group (33%) than in the nonoperative group (13.6%). The authors hypothesized that this finding, along with duration of symptoms, may be related to stage of PTTD at initial evaluation, which they were unable to include in the statistical model because of incomplete data. However, pain at initial evaluation did not differ significantly between the two groups.

A prospective study from the same institution, presented in March at the annual meeting of the American Academy of Orthopaedic Surgeons, found that supplementing brace treatment with a home strengthening regimen did not significantly improve Stage II PTTD outcomes compared to bracing alone.

The study included 37 subjects, all of whom were treated with an over the counter brace. In addition, 19 patients were randomized to an intervention group that was prescribed 12 weeks of strengthening exercises. The other 18 patients received passive treatment only.

Patients in the intervention group attended five sessions with a physical therapist, then were instructed to continue concentric and eccentric strengthening exercises at home for the remainder of the intervention period.

At six weeks, both groups had improved significantly on the Foot Function Index and the Short Musculoskeletal Functional Assessment compared to baseline levels; no further improvement was seen at 12 weeks. There was no significant difference between groups for either outcome measure at either time point.

“The exercise did not appear to make a significant difference. Therefore, we feel that bracing plays a larger role in the improvement,” said A. Samuel Flemister, Jr, MD, associate professor of orthopaedic surgery at the university, who presented the results at the AAOS meeting.

Researchers from the University of Southern California reported in the January 2009 issue of Physical Therapy that foot-specific eccentric exercises added to the effectiveness of orthotic treatment of PTTD; however, those exercises involved a custom-made device designed to isolate the posterior tibial tendon.

Smooth-soled athletic shoes reduce joint moments but not performance

Less may be more when it comes to athletic shoe traction, according to a study from the University of Calgary.

Comparing two athletic shoes with different degrees of outsole traction, researchers found that the shoe with less traction was associated with significantly lower joint moments at the knee and ankle during cutting maneuvers, suggesting a lower risk of injury. The findings were e-published on March 26 by the American Journal of Sports Medicine.

The investigators used motion analysis and a force plate to assess 13 recreational athletes as they performed running V-cuts on a sample track surface, under two shoe conditions. One shoe had a smooth sole, the other featured a tread.

The tread-soled shoe was associated with significantly higher peak external rotation moment at the ankle and peak external rotation and adduction moments at the knee, as well as knee adduction angular impulse. The high-traction shoe was also associated with significantly higher coefficient of translational traction and peak moment of rotation. However, no difference in performance was observed between shoe conditions.

Foot orthoses, calf stretching help relieve medial tibial pain in runners

Research from the University of Kansas suggests that foot orthoses and calf stretching can help reduce pain in runners with medial tibial stress syndrome, but that the benefits are more pronounced in male subjects.

The study included 11 men and 12 women with MTSS, all of whom ran or walked at least 10 miles per week. For three weeks, subjects wore fitted off-the-shelf foot orthoses during waking hours, and performed standard gastrocnemius and soleus stretches against a wall.

A successful outcome was defined as at least 50% improvement on the Numerical Pain Rating Scale after three weeks. This level of improvement was achieved in 44% of the  women and 83% of the men.

In the 15 subjects with a successful outcome, mean NPRS improved from 5.3 to 1.9. In the unsuccessful group, the mean NPRS score was 5.8 at baseline and 5.5 at follow up. A successful outcome was associated with a shorter duration of symptoms (mean of 181.6 days vs 412.8 days).

The findings were published in the February issue of Foot & Ankle Specialist.

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