September 2015

Risks of rigidus: Arthritis boosts hallux reamputation rates

In the moment: Diabetes

Partial hallux amputation in a patient with hallux rigidus. Image courtesy of Noah Oliver, DPM.

Partial hallux amputation in a patient with hallux rigidus. Image courtesy of Noah Oliver, DPM.

By Emily Delzell

Patients with diabetic neuropathy and hallux rigidus (HR) undergoing partial amputation of the hallux are 7.7 times more likely to need reamputation than their counterparts without HR, according to research from Georgetown University in Washington, DC.

The surgeon-investigators retrospectively analyzed 52 patients with a diabetic foot ulcer or plantar hallux infection who had undergone partial hallux amputation. All had diabetic neuropathy and had healed completely within six months of the initial hallux amputation; 31% had preoperative radiographic evidence of HR.

Demographics and comorbidities between those with HR and those without were not significantly different. After a mean follow-up of 126 ± 89 weeks, 31% of the group with HR (n = 16, 11 men) required reamputation for complicated surgical site reulceration, compared with 6% of those without HR (n = 36, 23 men).

Both arthritic and biomechanical changes can contribute to reulceration among patients with HR, said Noah Oliver, DPM, lead author of the study, which was epublished on August 6 by The Journal of Foot & Ankle Surgery.

“Some degree of limited joint mobility should be expected in patients with long-standing diabetes due to progressive stiffening of the collagen within the joint tissue, but any cause of limited motion, whether that is soft tissue stiffness or arthritic changes at the hallux, can contribute to both the initial ulcer and recurrence, especially in patients with diabetic neuropathy,” said Oliver, who is now a podiatric surgeon at Ochsner Medical Center in New Orleans.

The retrospective nature of the study meant the surgeons could evaluate only radio­graphic signs of HR.

“One might assume that arthritis changes are more likely to contribute to ulcer recurrence because the presence of radiographic arthritis corresponds with more advanced hallux rigidus, but a prospective study would be needed to learn more,” Oliver said.

The high reulceration rates in the HR group highlight the need for surgical or nonsurgical offloading to prevent wound recurrence and reamputation, he said.

“In the diabetic population, an equinus deformity at the ankle is often present and can be addressed with a gastrocnemius recession or Achilles lengthening. A lateral radiograph should be evaluated to rule out anterior ankle arthritis as a cause of equinus,” he said. “A rocker bottom type shoe with a custom molded orthotic and shoe modifications such a cutout under the hallux also work well to offload the plantar hallux.”

Georgeanne Botek, DPM, head of the Section of Podiatry and medical director of the Diabetic Foot Clinic at the Cleveland Clinic in Cleveland, OH, noted that, among this group of patients, prevention is best.

“A diagnosis of HR most often affects my prescription writing for footwear, which here might be a Morton’s extension or large metatarsal bar to off­load the metatarsal heads,” Botek said. “We often prescribe a plantar pressure-based insole that reduces pressure by about 30% at the metatarsal heads for patients with healed meta­tarsal head ulcerations, and this could be another potential group of patients we might prescribe that for.”

One unanswered question among patients with HR who require hallux amputation is whether that procedure should be partial or total.

“There is the theory that [total amputation] disrupts biomechanics, but I don’t think we have a lot evidence that, in removing the base of the proximal phalanx, we would see this complication,” Botek said. “I tend to remove the entire base when dealing with hallux interphalangeal joint osteomyelitis or septic arthritis.”

Either procedure can potentially be problematic, Oliver noted.

“Removing the entire hallux has negative effects on foot mechanics and medial arch stability due to disruption of the windlass mechanism. This may lead to transfer lesions under a lesser metatarsal or lesser toe deformity,” he said. “So, in a patient with hallux rigidus, both procedures could result in a reulceration. We don’t really know which procedure is optimal, but believe it is worth investigating.”

Source:

Oliver NG, Attinger CE, Steinberg JS, et al. Influence of hallux rigidus on reamputation in patients with diabetes mellitus after partial hallux amputation. J Foot Ankle Surg 2015 Aug 6. [Epub ahead of print]

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