March 2011

Positives for Ponseti

In the moment: Footcare

Photo courtesy of M.J. Markell Shoe Company, Inc.

Gait study compares clubfoot care

By Jordana Bieze Foster

Children with clubfoot treated with the Ponseti casting method have less pain and better function five to 10 years later than those treated surgically, according to gait analysis research from Baltimore that provides evidence to help justify the growing popularity of conservative clubfoot care.

The percentage of clubfoot patients treated with posteromedial release has decreased drastically since the mid-90s, which is thought to reflect the increasing appeal of conservative approaches such as the Ponseti serial casting technique. But few outcomes studies have directly compared the Ponseti method with casting, and none have done so using instrumented gait analysis.

“I think a lot of what’s going on in the Ponseti technique is more emotional than scientific,” said John E. Herzenberg, MD, head of pediatric orthopedic surgery at Sinai Hospital of Baltimore, who has been at the forefront of the technique’s emergence in the United States. Herzenberg presented his group’s research in February at the annual meeting of the American Academy of Orthopaedic Surgeons.

The Baltimore investigators performed gait analysis on 48 patients between the ages of five and 11 who had previously undergone treatment for clubfoot.  Twenty six patients (43 feet) were treated surgically at one institution at an average age of 10 months; 22 patients (35 feet) were treated from birth using the Ponseti technique at a different institution.

Patients in both groups differed significantly from a group of 34 children with unaffected feet for nearly all outcome variables measured. However, the conservatively treated patients generally outperformed the surgically treated patients, particularly with regard to dorsiflexion, calcaneal inversion/eversion, midfoot abduction/adduction, and dynamic internal rotation. The operative group also demonstrated significantly more residual varus foot pressure distribution and significantly less ankle power generation at push-off. The Ponseti group also significantly outscored the surgical group on three of four outcomes surveys, including the pain and global functioning components of the Pediatric Outcomes Data Collection Instrument.

“Neither group can be considered normal,” Herzenberg said. “But the Ponseti group had greater range of motion in the foot, more plantar flexion force production, more normal rotational profile, better gait velocity and step width, better foot alignment, less cavus and varus, and less pain.”

In a previous study published in the October 2009 issue of Clinical Orthopedics & Related Research, Austrian researchers found that nine children treated with the Ponseti method had more passive dorsiflexion and passive inversion/eversion than 10 children treated surgically. They also found that the conservative group scored better on the Functional Rating System of Laaveg and Ponsetti (which the Baltimore group did not use) but not the PODCI. However, mean follow up for the Austrian study subjects was just 3.5 years, compared to 6.3 years in the Baltimore study.

A second recent study comparing the Ponseti technique to surgical release looked specifically at the need for operative intervention and revision surgery. In that study, published in the February 2010 issue of the Journal of Bone & Joint Surgery, researchers from New Zealand reported a significantly lower recurrence rate in 40 feet treated conservatively than in 46 feet treated surgically.

Even in the Ponseti group the recurrence rate was relatively high, with 15 operative interventions required, but this may have been related to poor compliance with “boots and bar” wear. In the Baltimore study, only three patients in the conservative care group required additional surgery (neither involving a release) while 14 of 43 feet in the surgical group required repeat surgery.

Still, conservative care may not always be the answer, Herzenberg said.

“There are some kids no matter what that will need to have surgery,” he said. “If someone tells you they’re not doing any surgeries, they’re probably not telling you the truth.”

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