Indian Journal of Plastic Surgery Medknow Publications on behalf of Indian Journal of Plastic Surgery ISSN: 0970-0358 EISSN: 1998-376x Vol. 38, Num. 2, 2005, pp. 123-127

Indian Journal of Plastic Surgery, Vol. 38, No. 2, July-December, 2005, pp. 123-127

Original Article

Wound coverage of plantar metatarsal ulcers in leprosy using a toe web flap

Joshua J, Chakraborthy V

Premananda Memorial Leprosy Hospital, The Leprosy Mission, Kolkata
Correspondence Address:J. Joshua, Premananda Memorial Leprosy Hospital, 259 A, Acharya Prafulla Chandra Road, Maniktala, Kolkata 700006, West Bengal, India, E-mail: tlmkolkata@tlm-india.org, jerryjoshua@yahoo.com

Code Number: pl05025

Abstract

Keywords: Plantar metatarsal ulcers, Plantar metatarsal artery, Digital artery, Leprosy, Toe web flap

Introduction

Disintegration of the feet is the most common problem faced by leprosy patients and a major part of this is associated with plantar ulceration.

Plantar ulceration serves as both the cause and the effect of such disintegration. Among those with plantar ulceration, ulcers of the forefoot contribute 70% of the total.[1] 55% of ulcers occur over the metatarsal heads[1]. These ulcers over the plantar aspect of the metatarsal heads may occur as sinuses leading down to the underlying structures or as shallow ulcers involving the tissues at various levels.[1] These ulcers occur and recur

1. due to repeated high direct pressure and
2. due to the shearing stresses on the normal tissue or the scar beneath the metatarsal heads on walking[2].

Where these ulcers have penetrated the underlying tissues down to the bone and into the metatarsophalangeal joint, there is no choice but to excise the joint through a dorsal incision and salvage as much plantar tissue as possible and minimise the scar on the plantar aspect by closing the plantar wound to promote healing by primary intention.[3] When the tissue involvement stops short of bone, then healing by secondary intention can be promoted by immobilisation.

Recurrence of these ulcers is common (8 % within one year in our series) in spite of providing appropriate footwear with orthosis to redistribute pressure and minimize shearing stresses. These forces were addressed by providing extra padding in the form of a toe web flap[4] based on the plantar metatarsal artery and its digital branch. In this paper, the procedure for the toe web flap and the results of this procedure on 13 patients are presented and discussed.

Materials and methods

Of 708 patients with plantar metatarsal ulcers seen over a four-year period, 257 cases underwent dorsal incisions and excision of the metatarsophalangeal joint because of septic arthritis of that joint. Thirteen who had involvement of the underlying tendon or joint capsule without septic arthritis, underwent the toe web flap procedure described below. The rest were treated non-operatively by immobilization alone, as the deeper structures were not involved. In 22 of these cases, the wounds were larger than 3.5cm x 3.5cm and a toe web flap would not have sufficed.

The work was done between 1^st March 2000 and 28th February 2004, a total of four years.

Operative technique
Indications
This procedure was performed in patient with plantar metatarsal ulcers or sinuses, not involving the metatarsophalangeal joints in an anaesthetic foot. Defects ranged between 1.5cm x 2cm and 2.5cm x 3.5 cm. The ulcer was shallow or deep involving the tendon or tendon sheath. Chronic inflammation was sometimes present. There was however no infection or cellulities.

Pre-operative preparation
The patient was admitted and taught walking with crutches. All patients who came with infection of the forefoot wound or other sites of infection were treated with a course of broad-spectrum antibiotics preoperatively and the wound was debrided. Septic tenosynovitis was also dealt with, in addition, by immobilisation in a weight bearing window plaster cast until the discharge from the wound subsided.

Anaesthesia
Spinal anaesthesia was prefered but ankle block anaesthesia was also used.

Procedure
The plantar sinus or ulcer was first excised taking care not to injure the plantar metatarsal artery and its digital branch to the side of the toe donating the flap (usually the lateral aspect of the big toe). The flap of required dimensions was outlined on the lateral aspect of the big toe taking care to avoid the nail and nail bed. A longitudinal incision was marked from the most proximal part of this island flap to the base of the toe (if this was not already occupied by the base of the flap). Then an angular incision was marked to connect this to the defect. [Figure - 1] [Figure - 2] [Figure - 3] [Figure - 4] [Figure - 5] [Figure - 6] [Figure - 7] [Figure - 8] [Figure - 9] [Figure - 10]

The incision was then made starting from the distal aspect of this flap and including the digital neurovascular bundle of the lateral aspect of the big toe in the flap. This was raised proximally and the flap was islanded incising the skin and subcutaneous tissue superficially at the proximal extent of the islanded flap. The connecting incision between the island flap and the plantar metatarsal defect, which had been marked out already, was made. The plantar digital artery and the plantar metatarsal artery were dissected out along with the plantar digital nerve and the entire neurovascular bundle was raised deep to the superficial transverse metatarsal ligament after cutting this ligament. The flap was laid on the plantar defect and sutured. The connecting incision was also closed and the secondary defect is closed with a split thickness skin graft.

Sutures were removed on the 10th post operative day and when the wounds had completely healed, usually by the 21^st post operative day, walking exercises were started. All patients were provided with appropriate orthosis and footwear

Results

Thirteen cases underwent this procedure, nine for defects over the 1^st metatarsophalangeal joint, three over the 2^nd or 2^nd and 3^rd metatarsophalangeal joint region and one over the 5^th metatarsophalangeal joint region. Three patients were female and ten were male. Their ages ranged from 20 to 63. The median age was 38 years. The duration of the ulcer ranged from 5 months to 12 years. The median duration was 12 months. Follow up ranged from 6 months to 36 months (median 13 months).

The donor site for all the flaps, except one, was the lateral aspect of the big toe. The exception was the flap used to cover the 5^th metatarsal plantar defect where the flap was taken from the lateral aspect of the 4th toe. The dimensions of the defects after excision ranged between 1 x 1 sq cm to 3.5 x 3 sq cms. The dimensions of the flaps ranged between 1.5 x 1.5 sq cms to 3.5 x 3.5 sq cms.

All the cases did well with no recurrence of ulcers at last follow up.

Complications seen in the immediate post operative period included loss of skin graft over the secondary defect in four cases and wound dehiscence in four cases. In three cases the skin graft was reapplied and in one case the secondary defect healed by secondary intention. In those cases with wound dehiscence, all the flaps were re-sutured and in one of these cases, extensor tenotomy was also needed to be done to facilitate flap closure as the un-opposed action of the extensor caused the toe to cock-up and prevent plantar wound apposition. In the late post operative period, complications were seen in two cases. One case had developed a callous at one edge of the flap two years after the procedure. This was managed by asking the patient to soak her feet in water every day and scrape the callous. The other was a sinus of the edge of the flap over the 5^th metatarsophalangeal joint with dislocation of the joint. This was managed non-operatively by immobilisation.

Discussion

Many flaps have been described in the management of plantar ulcers over the metatarsophalangeal joints. Fritschi[1], and later Pring and Casabianca[3] have suggested excision of the metatarsophalangeal joint through a dorsal incision in cases where the metatarsophalangeal joint has been involved through the ulcer. They have advocated debriding the plantar wound and closing it by sutures, leaving a dorsal drain. We have extensively used this procedure where there is co-existing septic arthritis and / or disintegration of the joint. If the plantar ulcer or sinus does not involve the joint, we have tried to cover the defect with the toe web flap[4]. Curtin[5] has described a transposition flap from the plantar midfoot, based laterally. This tended to scar the foot extensively and left an area of the instep with a secondary defect needing a skin graft. Emmett[6] has described a filleted toe flap for this purpose. An entire toe is sacrificed in this procedure with the resultant cosmetic defect. Reiffel[7] has described a versatile plantar artery skin fascia flap, which moves to cover defects of the forefoot and is based on the lateral plantar artery. This involves extensive dissection of the sole, leads to a large area of scarring and may be useful for large defects. Martin et al[8] described a medial plantar flap with a lateral plantar pedicle to cover large defects of the forefoot. The dissection required is meticulous and extensive leaving an equally extensive scarred area and a skin graft over the instep. But we think that though there is a place for such a flap, small defects as those we have encountered, can be dealt with by smaller flaps.

Dong et al[4] first described the first toe web flap to cover defects over the 1^st and 2^nd metatarsophalangeal joints. They used only the big toe as the donor site and covered defects confined to the 1^st and 2^nd metatarsal region. Gravem[9] has also described a similar flap from a toe adjacent to the ulcer and has called it the 'toe island flap (Digital Artery Island flap)'

In this series we have used the flaps to cover defects over any of the metatarsophalangeal joints on the plantar aspect, based on the plantar metatarsal artery and the digital artery, not only of the first toe web but also of the 4th toe web. The secondary defects are not over the sole but over the lateral aspect of the donor toe. The extent of scarring of the sole is restricted to the area of the defect and the incision to the toe web space. In those cases where the secondary defect skin graft did not take, healing was by secondary intention with no discernable disadvantage.

Conclusion

References

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