PEER REVIEW PRESENTATION
By J. Monroe Laborde, MD, MS
Presented in the Journal of the Southern Orthopaedic Association
Forefoot ulcers are common complications of neuropathy. Trans-tibial amputation too often becomes necessary when progressive infections develops secondary to ulcers of the forefoot. Tendon lengthening appears to be an effective treatment for planar forefoot ulcers in patients with neuropathy and forefoot ulceration,
Diabetic foot problems are the leading cause of amputation1. Five toten percent of diabetic patients will require amputation1. Over fifty thousand amputations occur annually in diabetics in the United States.2 Eighty-five perrcent of lower-extremity amputations are preceded by foot ulcers in patients with diabetes mellitus.2
Guyton and Saltzman3 discussed in detail the etiology of foot ulcers in diabetic patients. In the absence of large-vessel disease, diabetic foot disease results from the combination of neuropathy and abnormal mechanical stress.3 Deformity that increases pressure on a portion of the foot can instigate ulceration in a patient with diabetic neuropathy.3 Peripheral neuropathy results in loss of protective sensation and lack ofrecognition of repetitive mechanical stress which often cause forefoot ulcers in diabetic patients.4
Daniels5 stated that diabetic neuropathy contributes to the development of equinus contracture of the ankle which increases pressure on the forefoot. The high forefoot pressure is consistent with the most common locations of foot ulcers being the plantar surface of the first three metatarsal heads and the hallux5.
Foot ulcers can cause deep spreading infection which can result in leg amputation.5 Prevention and care of foot ulcers would prevent most leg amputations in diabetics.5
Patients with a history of foot ulcers have abnormally high pressures at healed ulcer sites.6 Plantar foot ulcers occur at sites of high pressure.7 The combination of neuropathy and equinus contracture have been implicated in the cause of forefoot ulcers8. Reducing the risk of neuropathic ulceration of the foot should be accomplished by decreasing pressure on the forefoot.6 Pressure relief has been accomplished by shoe modification, total contact casts and Achilles tendon lengthening.9 Achilles tendon lengthening has been shown to promote healing of chronic foot ulcers in patients with neuropathy.8,10 Healing occurred even in patients who did not heal in total contact cast with less ulcer recurrence.10 Dorsiflexion metatarsal osteotomy also is effective in healing chronic neuropathic forefoot ulcers but with a much higher complication rate11.
Successful treatment of ulcers and prevention of amputation areimportant objectives for those who manage patients with neuropathic forefoot ulcers. This report describes the results of a group of patients who had forefoot ulcers treated with tendon lengthenings.
Materials and Methods
Between May of 1995 and October of 2001, sixteen patients who had neuropathy and one or more plantar forefoot ulcers agreed to surgical tendon lengthening. Ulcers of metatarsal heads we treated with lengthening of the gastrocnemius-soleus mechanism. The Vulpius technique12 was used, transecting the aponeurotic tendon of the gastrocnemius and soleus in the mid calf (see Figure 1). The patient’s ankle was then placed in neutral in a short leg walking cast for six weeks. Toe ulcers were treated with toe flexor tendon tenotomy percutaneously at the proximal phalanx. First toe ulcers had both procedures at the same time if the patient would agree. Patients were allowed to go home the day of surgery unless they were in the hospital for another reason.
The Vulpius procedure lengthens the gastrocnemius tendon and soleus aponeurosis proximal to the actual Achilles tendon. The lengthening effect on the ankle and foot is the same as tendon lengthening and the terms gastrocnemius-soleus lengthening by Vulpius technique, Vulpius type Achilles tendon lengthening and Vulpius procedure are used interchangeably.
The amount of active ankle dorsiflexion with the knee in full extension was measured pre-operatively with a goniometer. Pulses were measured by palpation of dorsalis pedis and posterior tibial arteries
Ulcers were graded using Wagner’s 13 classification: grade one is superficial; two is deep, extending to ligament, tendon, joint capsule, fascia or bone; three is grade two with infection (abscess, osteitis or osteomyelitis); four is gangrene of the toe or forefoot; five is gangrene of the entire foot. Grades three to five were not included unless grade three could be transformed to grade one or two by antibiotics. Patients with prior gangrene of toes, abscess and/or osteomyelitis had been treated in the past by toe amputation, metatarsal head resection, abscess drainage and/or debridement by other physicians, but were not excluded from this study.
The size of the ulcer was measured and duration of the ulcer was obtained from the patient. The presence of neuropathy was determined by the nylon monofilament test.14
The patients were assigned a number in the order they had their first tendon lengthening surgery (see table). All sixteen patients had neuropathy by monofilament test. Fourteen had diabetes mellitus. Patient number four had neuropathy after lumbar surgery and number six had alcoholic neuropathy.
Ages of patients ranged from forty-four to eighty-one at the time of surgery, and averaged sixty-one. There were eight males and eight females. Eleven had palpable pedal pulses and five did not. All patients who had a Vulpius procedure for metatarsal ulcers had ankle contracture with inability to dorsiflex the ankle beyond neutral (zero degrees dorsiflexion or less).
Patient number one had ulcers bilaterally, and had Vulpius procedure bilaterally eleven months apart. The first metatarsal ulcers healed but a transfer ulcer of the first toe developed unilaterally four months after the second Vulpius procedure. This transfer ulcer also healed after the toe flexor tendon was cut.
There were twenty surgeries on nineteen ulcers in sixteen patients. Patient nine had a second surgery (Vulpius procedure) when his first toe ulcer did not heal in six weeks after toe tenotomy. Nine ulcers were grade one and ten were grade two. Seven patients (with eight ulcers) had infection treated with antibiotics. Once infection appeared to be under control, tendon lengthenings were performed.
Four patients had had one or more toes previously removed. Patient number six had had her first metatarsal head removed and patient number five had the first, second and third metatarsal heads (and the first and third toes) removed in the past. Patient five had a particularly extensive ulcer (Figure 2). This ulcer healed after Vulpius procedure and the patient did not have any recurrent ulcers and the skin of her foot was intact when she died of medical problems eighteen months later.
The diameter of thirteen ulcers was one centimeter or under and two were over three centimeters. Six ulcers were located under the first metatarsal head or stump, six under the first toe, three under the second toe, one under the base of the fifth metatarsal and one under each of the second, third and fourth metatarsal head.
Patient number nine with a first toe ulcer initially consented to only percutaneous release of that toe flexor. The ulcer did not heal in six weeks but healed later after Vulpius procedure was performed. Because of the experience with patients one (first toe ulcer developed unilaterally on side of Vulpius procedure alone and not on side of both Vulpius and tenotomy of toe) and patient nine (first toe ulcer not healing after toe flexor cut and healing after Vulpius procedure), Vulpius procedure was recommended in addition to toe flexor lengthening for later first toe ulcers.
Ulcer duration prior to surgery ranged from one month to seven years (average fourteen months). Most patients had had unsuccessful attempts to heal the ulcer with stretching exercises, decreased weight bearing, debridement, and shoe modification.
In all patients but number nine (discussed above) and eleven, the ulcers healed in less than six weeks. Patient eleven was on dialysis and had Charcot arthritis of midfoot and severe arterial insufficiency. The ulcer did not heal and he later developed gangrene of the foot and required amputation.
All incisions healed primarily without any infections. There were no ulcer recurrences or transfer metatarsal head ulcers. There were two transfer ulcers in toes (patient one, first toe; patient fourteen, third toe) both of which later healed after toe tenotomy. No new deformities developed after the tendon lengthenings.
Follow up was in person for fourteen procedures and by phone for six. The follow up ranged from six months to seventy-five months excluding patient nine’s first surgery (Vulpius procedure six weeks after toe tenotomy not healing first toe ulcer). The average follow up for the other nineteen procedures was twenty-eight months.
There were three complications in addition to those described above. Patient number one had a pulmonary embolus over three months after the first surgery, but recovered completely. Patient number thirteen developed a heel ulcer post operatively, which healed almost completely with no additional problems. Patient sixteen had an open dislocation of her fifth toe treated with amputation.
The number of patients and the length of follow up of some of the patients are both small enough to consider the results preliminary. The relatively high rate of ulcer healing, amputation prevention and relatively low complication rate help compensate for the weaknesses of this study.
The association of gastrocnemius-soleus contracture, neuropathy, and chronic ulceration of the forefoot in this group of patients was previously reported by Yosipovitch and Sheskin8 and by Lin, Lee and Wapner.10 The patients of Lin et al who had Achilles tendon lengthening all had flexion contractures which was also the case in this series. The high rate of successful healing of forefoot ulcers in prior studies, seven of eight 8 and fourteen of fifteen10, was similar to this report, eighteen of twenty. Lin et al’s one failure was due to osteomyelitis of the metatarsal head.10 Patient nine’s ulcer failed to heal after tenotomy of first toe but healed after Vulpius procedure. Patient eleven’s failure to heal was felt to be due to a combination of peripheral vascular disease, ulcer infection and Charcot arthritis. Yosipovitch and Sheskin8 had three ulcer recurrences in four to five year follow up. Both Lin et al.10 and this study found no ulcer recurrences, obvious gait problems, or new deformities after tendon lengthening. The absence of recurrent ulcers in this series compares favorably with the reported recurrence rate of foot ulcers in 558 diabetic patients after one, three and five years of 34%, 61% and 70% of patients.15 Lin et al’s10 average follow up was seventeen months, compared to twenty-eight months in this study.
Dorsiflexion metatarsal osteotomy also had a high rate of successful healing of neuropathic forefoot ulcers (21 of 22).11 There was, however, a 68% complication rate with seven patients developing acute Charcot disease, three developing midfoot ulcers, three deep wound infections, two transfer ulcers under adjacent metatarsal heads, and one below knee amputation. This study revealed no new Charcot disease, mid foot ulcers or wound infections. There were three transfer lesions, a first toe ulcer in patient one, a third toe ulcer in patient sixteen and the heel ulcer in patient thirteen. Two patients subsequently required amputation for gangrene (seven and eleven), but none for progressive infection.
Gangrene was felt to be a contraindication to tendon lengthening. Patients without pulses, however, were felt to be potentially salvageable since there were no incision problems and ulcers healed in all but one of the patients without pulses. Quantitation of vascularity in patients without pulses might be helpful in predicting success but was not done in this study.
Lin et al. lengthened the Achilles tendon by Hoke’s method16 of hemisection at three levels of the tendon. Yospovitch and Sheskin used the subcutaneous tenotomy method of Strohmeyer.17 The author chose the Vulpius technique12 because of his prior favorable experience with this technique in children with cerebral palsy (less over correction and incision problems). Sharrard and Bernstein 18 recommended gastrocnemius recession in cerebral palsy patients who lacked passive ankle extension beyond a right angle. They preferred this technique to Achilles tendon lengthening because of less recurrence and incision problems in their series and because they felt under correction was preferable to over correction. Which technique for tendon lengthening is best for forefoot ulcers has not yet been determined and at this point should probably be left to the discretion of the surgeon.
The purpose of tendon lengthening is to decrease stress on the area of ulceration. Tenotomy of the toe flexor tendons is done to decrease stress on the plantar surface of the toe. The lengthening of the gastrocnemius-soleus mechanism should decrease stress on the plantar forefoot and the area of ulceration. Armstrong et al9 confirmed that Achilles lengthening does in fact decrease pressure on the forefoot and recommended the procedure as an adjunctive therapeutic and prophylactic measure to reduce the risks of neuropathic ulceration.
Another study should be done to determine if daily calf stretching can prevent progression of callouses to ulcers in patients with neuropathy, and can prevent gastrocnemius-soleus contracture, forefoot callouses and ulceration in diabetics if started before the development of these problems. Since calf stretching might help and probably would not harm diabetic patients, it now seems reasonable to recommend prophylactic calf stretching to them.
Further investigation is needed to confirm the results of this preliminary report. The results of this series of patients suggests that lengthening of the tendon-muscle unit is effective treatment for forefoot ulceration. These lengthenings would not be expected to prevent amputation in patients with severe peripheral vascular disease. This procedure usually prevents progression of neuropathic forefoot ulceration to infection and subsequent amputation. A follow up study is under way to better document these findings with more
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