A Guide To Effective Forefoot Salvage Procedures

By Eric M. Feit, DPM, and Mary M. Peters, DPM

It is believed that 15 percent of diabetics will develop a foot or leg ulceration at some point during the course of their disease and that 50 percent will recur within 18 months.1 Approximately 80 percent of diabetic ulcers occur plantarly due to abnormal pressures. Most of these ulcers can be treated with sharp debridement, offloading devices and local wound care.2-4 Once you’ve achieved ulcer healing, utilizing custom orthotics with extra depth shoes will often prevent recurrence and reduce the needed frequency of pre-ulcerative keratoma debridements. Unfortunately, many ulcerations develop acute infections or reoccur despite our best conservative efforts. At this point, we must consider surgical intervention as a vital part of the treatment plan for these patients. The primary goal of diabetic foot surgery is to salvage as much of the foot as possible and reduce the risk of lower extremity amputation. A secondary goal is to maintain functional stability and allow the patient to make a quicker return to his or her daily, recreational and work activities. When we discuss foot surgery with a diabetic patient and his or her family, there is often tremendous anxiety. It is critical to explain the goals of the procedure and that an additional procedure or amputation may be necessary. By performing surgery, we’re often able to prevent the need for amputation in the future. Several studies have revealed that once a diabetic lower extremity amputation has been performed, the risk of additional amputation is greater than 50 percent within five years. In addition, the three-year survival rate after an amputation is only 50 percent.5-6 Be Aware Of Pertinent Biomechanical Considerations When contemplating surgical management of a recurrent ulceration or acute infection, you should always consider the biomechanical effects of the foot that may have contributed to the cause of the ulceration as they may influence the results of surgical treatment. For example, plantar hallux ulcers are often caused by hallux limitus and ankle equinus, which can be treated surgically. Therefore, some surgical procedures will result in fewer post-op complications and better outcomes if you address the biomechanics at the time of surgery. Employing custom orthotics in conjunction with surgical care will also help facilitate improved patient outcomes. Orthotics will help minimize the complexity of surgical procedure choices. For example, if the primary cause of a plantar hallux ulceration is hallux limitus with abnormal pronation, then performing a Keller bunionectomy and utilizing a slightly inverted functional foot orthotic should address the biomechanical etiology, minimize pressure under the hallux and prevent recurrence. Keep in mind the most common diabetic forefoot wounds occur at the plantar aspects of the metatarsal heads, the plantar aspect of the hallux and the dorsal and distal aspects of the digits. These are areas of the foot that receive the most stress and shearing forces in gait. How Should You Address Ulcerated Lesser Digits? Lesser digits have the greatest risk of ulceration when motor neuropathy results in contracture of the joints. Distal digital or dorsal joint ulcers quickly occur from shearing forces and pressure against shoes. When considering hammertoe repair on a patient with diabetes, it is crucial to remember that motor neuropathy will persist following repair, making an arthroplasty a short-lived solution. Therefore, arthrodesis procedures are preferred for treating proximal IP joints unless there is bone infection. Due to intrinsic muscle wasting and neuropathy, ulcers often develop at the tip of the distal phalanx, dorsally over the proximal or distal phalanx or on the side of the digit due to pressure from an adjacent toe. Although amputation is an option, it is often unnecessary if bone infection is localized to the ulcer site. In this instance, performing an arthroplasty or distal tuft resection (terminal Symes) is preferable. A flexor tenotomy is also an option for treating flexible hammertoe deformities. Reviewing The Options For First Ray Dilemmas The primary causes of ulceration at the plantar aspect of the hallux or first metatarsal are abnormal biomechanics and structural deformities. Ulcers underneath the hallux are often due to abnormal pronation, hallux limitus, enlarged condyles or an accessory sesamoid.

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