A Guide To Effective Forefoot Salvage Procedures
- Volume 16 - Issue 4 - April 2003
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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. Treatments include a hallux IP arthroplasty or Keller bunionectomy.
In our experience, IP arthroplasties only work well in sedentary patients. Active patients often develop a hallux extensus deformity or hallux hammertoe (malleus). The Keller bunionectomy seems to alleviate pressure more effectively and is preferable unless the distal portion of the proximal phalanx is infected. In cases of hallux malleus, be aware that a distal ulceration often develops, which you may treat with an IPJ fusion.
Plantar first metatarsal head ulcers are more challenging to treat surgically due to the greater involvement of biomechanical forces. First metatarsals are often rigidly plantarflexed in the diabetic patient. In order to correct this problem and prevent recurrent ulceration, you’ll usually need to perform a proximal metatarsal procedure. We have found that plantar condylectomies and/or sesamoidectomies have unpredictable results. We prefer to perform a sagittal Z osteotomy or a Juvara C procedure in order to achieve an adequate amount of first ray dorsiflexion and alleviate plantar pressures.
Key Pointers For Treating Lesser Metatarsals
You’ll often find that the plantar metatarsal heads of diabetic patients have excessive pressure due to neuropathic changes. In cases of chronic neuropathy, the foot develops an anterior cavus and ankle equinus, causing hammering of the digits, plantarflexion of the metatarsals and early heel-off during gait.7 Additionally, a diabetic patent may have fat pad atrophy, reducing the cushioning to the metatarsal phalanageal joints that are now receiving extra pressure.
Ideally, you can alleviate this pressure with custom orthotics, extra depth or rocker bottom shoes, keratoma debridements and emphasizing stretching exercises for equinus.8 In 1992, a study by Young demonstrated that regular debridements of keratomas caused by repetitive pressure reduce the peak plantar pressures by 26 percent.9 Other studies have revealed that patients seen more frequently in a foot clinic had less severe ulcerations and were less likely to undergo surgery than those who had infrequent care.6,8
However, if the keratomas or ulcers persist, performing a pan metatarsal head resection in conjunction with a first MTP joint fusion, hammertoe repair and possible tendo-Achilles lengthening may be necessary.10 It is our preference to avoid using first MTPJ implants with a pan metatarsal head resection because these patients often have a higher risk of postoperative infection and may have preexisting soft tissue or bone infection. Performing arthrodesis of the PIPJs of digits 2 to 4 is also recommended in order to stabilize the muscle imbalance to these joints and reduce retrograde pressure to the forefoot. If ankle equinus is present, a gastrocnemius recession or percutaneous TAL is vital to preventing recurrent ulceration.
Individual plantar metatarsal ulcers may also occur due to abnormal metatarsal length, trauma or prior bone infection. In these instances, you may perform isolated metatarsal procedures such as condylectomies, osteotomies and resections. However, if more than one metatarsal is involved, performing a pan metatarsal head resection will produce a more predictable and manageable outcome.
It is encouraging that more than 80 percent of diabetic-related amputations are preventable with regular podiatric exams, patient education, custom orthotics and, sometimes, surgical intervention.6 Surgical management plays a vital role in preventing diabetic foot infections and amputation. New advances in podiatric surgical care will hopefully further reduce the incidence of amputation for the next generation of patients with diabetes.