British Journal of Plastic Surgery (1997), 50,284-287 0 1997 The British Association of Plastic Surgeons

The distally based islanded dorsal foot flap

V. S. Bharathwaj and A. A. Quaba

Department of Plastic Surgery, Royal Hospitalfor Sick Children, Edinburgh, UK

SUMMARY A modification of the distally based first web space flap on the dorsum of the foot is described. This flap, originally described by Earley and Milner, has been completely islanded on its blood supply and used to resurface defects following release of post-burn hyperextension contractures of the toes. Our experience with 14 consecutive flaps is presented. Partial necrosis occurred in three flaps, one leading to slight residual contracture. We have found this flap reliable and easy to raise, and the donor site morbidity is minimal.

Thermal injuries to the feet are quite common in children, most being due to scalds. While the majority are superficial and tend to heal without significant scarring, a proportion of them will develop contrac- tures. These can occur even when the burn has been primarily debrided and grafted, as the graft or scar tissue contracts and fails to keep pace with the child’s growth. Post-burn hyperextension contracture of the toes is a particularly difficult problem to correct and can be quite severe and progressive, leading to sub- luxation of the metatarsophalangeal joints, callosities over unusual sites and gait abnormalities (Figs 1, 2).’ Release of these contractures leaves a distal dorsal defect which is difficult to resurface. Skin grafts tend to contract and may be unsuitable when extensor teno- tomies or dorsal capsulotomies have been performed.

Earley and Milner’ described a distally based flap of the first web space in the foot based on the distal cutaneous branches of the first dorsal metatarsal artery and its communication with the plantar meta- tarsal artery.

The first dorsal metatarsal artery arises from the dorsalis pedis in 80% of individuals and two types are

described, one superficial and one deep. Regardless of the origin or type of the vessel, cutaneous vessels arise in the distal web space from the arcade linking the dorsal and plantar metatarsal arteries.’

Fig. 1

Figure l-Hyperextension contractures of the metatarsophalangeal joints.

Fig. 2

Figure 2-X-ray of a foot demonstrating severe post-burn hyperextension contractures of the MTP joints.

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Dorsal foot flar, 285

Hayashi and Maruyama4 described an islanded dorsal foot flap for post-traumatic defects of the distal foot, but felt that it was essential to include the entire first dorsal metatarsal artery in this flap, which was therefore a reverse flow flap. Sakai’ also used the islanded first dorsal metatarsal artery, but for the coverage of a plantar defect of the great toe. Lai et al6 avoided sacrificing the first dorsal metatarsal artery by using adipofascial turnover flaps for dorsal foot defects using perforators at the base of the flaps with- out a skin bridge.

Wechselberger et al.’ reported an islanded flap based on the branches of the first dorsal metatarsal artery to cover distal foot defects, using only the subcutaneous tissue and covering it with a split skin graft. Onishi and Maruyama8 meanwhile further described a V-Y advancement of the dorsal metatarsal flap for dorsal foot reconstruction.

Our modification of the flap described by Earley and Milner consists of completely islanding the skin flap on the cutaneous branches, and this paper describes our clinical experience with the flap used to provide coverage of defects following release of post- burn hyperextension contractures of the toes.

correspond to the size of the defect. The dissection starts proximally in a plane superficial to the para- tenon of the extensor hallucis longus tendon. It must be emphasized that no attempt is made to dissect out or even identify the first dorsal metatarsal artery. Dissection proceeds distally until a leash of vessels is seen entering the flap in the distal part of the web space. The flap can now be safely islanded on a sub- cutaneous pedicle containing these vessels and trans- posed 90” to be inset into the defect. In our experience, this flap can usually be safely raised on a previously scarred dorsum of a foot. The donor site is then closed primarily or, if too wide, covered with a split skin graft.

Patients

Fourteen flaps were used in nine patients, live patients undergoing the procedure bilaterally. Details of the patients are in Table 1. Primary closure of the donor site was achieved in five feet and the rest were skin grafted. The size of the flaps ranged from 5 x 2.5 cm to 8x5cm.

Operative technique Table 1

The procedure is carried out under tourniquet (Fig. 3). The contracture is first released over the metatarso- phalangeal (MTP) joints, tenotomies and/or dorsal capsulotomies are carried out as required. It may be necessary to stabilize the MTP joints in a neutral position [O’] with K-wires. The flap is then outlined to

No. of patients No. of flaps 14 Age at burn 16 months* (3-28 months) Age at release 5.5 years* (2-10 years) Hospital stay 11.7 days* (42 1 days) Follow-up 3.25 years* (l-6 years)

* Mean values. Figures in parentheses: range.

9

Fig. 3

Figure Operative technique. (A) Contracture released, MTP joints fixed with K-wires, flap raised and completely islanded. (B) Flap transposed after tourniquet release, with good perfusion,

286 British Journal of Plastic Surgery

Results

There was no complete flap loss; however, three of the flaps suffered distal necrosis and were allowed to heal spontaneously (Fig. 4). One of these patients had a residual contracture of the 5th toe. None of these patients required further intervention. One patient, who underwent fixation of the MTP joints with K-wires, presented 3 weeks later with migration of a K-wire into the sole of the foot which was removed after a minor operation. Patients were followed up for

Fig. 4

Figure &Distal necrosis of flaps raised on scarred tissue.

Fig. 5

an average of 3.25 years. None of the patients had significant recurrence of their contractures, although some of them went on to have contracture releases at other sites. There were no problems with the donor site in any of these patients, either immediately or at subsequent follow-up (Figs 5, 6).

Discussion

The traditional approach to contracture releases with coverage by skin grafts can pose several problems in the distal foot with hyperextension contractures of the toes. The bed may not be suitable for skin grafts, especially when tenotomies or capsulotomies are performed. Besides, the grafts, which are difficult to splint, can con- tract leading to recurrence of the deformity.9~‘0 However, there are very few local flaps available in this region suitable for this purpose.

There have been several studies on the vascular anatomy of this region and the dorsal metatarsal arteries in particular. While the origin of the first dorsal metatarsal artery is subject to some variation in 20% of the population, the cutaneous branches in the distal web space are usually present. The islanded dis- tally based dorsal foot flap is dependent only on these branches and hence the actual origin of the Grst dorsal metatarsal artery is not critical to the planning, raising or survival of this flap. The original flap described by Earley and Milner, is somewhat limited in its reach with its distal cutaneous bridge intact. Our attempts to push this flap to its limit by islanding it on its vascular pedicle have been successful and makes it analogous to the dorsal hand flaps described by Quaba and Davison.”

It is obvious from the ability to consistently island this flap, which has been successfully raised even on

Fig. 6

Figure S-Healed donor sites following direct closure (2 years postoperative). Ankle contractures have also been released. Figure &Healed donor sites after skin grafting (2 years postoperative).

Dorsal foot flap 287

previously scarred feet, and the large size of some of the flaps in this series that it has a defined blood supply and is not a random pattern flap.

It is important to point out that in raising this flap no attempt is made to identify the first dorsal meta- tarsal artery as the dissection is entirely superficial to the paratenon. This avoids potential problems with the donor site which have been well documented when the plane of dissection is deeper, as in raising the dorsalis pedis flap.12,”

Distal necrosis can be a problem, especially if there is extensive scarring, and care is needed in elevating the flap in such cases.

5. Sakai S. A distally based island first dorsal metatarsal flap for the coverage of a distal plantar defect. Br J Plast Surg 1993; 46: 480-2.

6. Lai C-S, Lin S-D, Yang C-C, Chou C-K. Adipofascial turn-over flap for reconstruction of the dorsum of the foot. Br J Plast Surg 1991; 44: 1704.

7. Wechselberger G, Schwabegger A, Papp CH, McGraw J. The distally based subcutaneous tarsometatarsal flap. Eur J Plast Surg 1995; 18: 297-300.

8. Onishi K, Maruyama Y. The dorsal metatarsal V-Y advance- ment flap for dorsal foot reconstruction. Br J Plast Surg 1996; 49: 170-3.

9. Alison WE, Moore ML. Reilly DA, Phillips LG, McCauley RL, Robson MC. Reconstruction of foot burn contractures in children. J Burn Care Rehabil 1993; 14: 34-S.

10. Waymack JP, Fidler J, Warden GD. Surgical correction of burn scar contractures of the foot in children. Burns 1988; 14: 156660.

Conclusion 11. Quaba AA, Davison P The distally-based dorsal hand flap. Br J Plast Sum 1990: 43: 28-39.

The islanded distally based dorsal foot flap is useful for coverage of defects following release of hyper- extension contractures of the toes. In an area where there are very few flaps available, we recommend its use as a reliable flap, which is easy to raise and has few donor site problems.

12. Franklin JDyWithers EW, Madden JJ, Lynch JB. Use of the free dorsalis pedis flap in head and neck repairs, Plast Reconstr Surg 1979; 63: 195-204.

13. Zuker RM, Manktelow RT. The dorsalis pedis free flap: tech- nique of elevation, foot closure, and flap application. Plast Reconstr Surg 1986; 77: 933102.

References 1. Jackson D. Acquired vertical talus due to burn contractures.

J Bone Joint Surg 1978; 60-B: 215-18. 2. Earley MJ, Milner RH. A distally based first web space flap in

the foot. Br J Plast Surg 1989; 42: 507-l 1. 3. Man D, Acland RD. The microarterial anatomy of the dorsalis

pedis free flap and its clinical applications. Plast Reconstr Surg 1980; 65: 419-22.

4. Hayashi A, Maruyama Y Reverse first dorsal metatarsal artery flap for reconstruction of the distal foot. Ann Plast Surg 1993; 31: 117-22.

The Authors K S. Bharathwaj FRCSEd, Formerly Registrar A. A. Quaha FRCS(Plast), Consultant Plastic Surgeon Department of Plastic Surgery, Royal Hospital for Sick Children, Sciennes Road, Edinburgh EH9 1 LF, UK.

Correspondence to A. A. Quaba FRCS(Plast)

Presented at the Winter Meeting of the British Association of Plastic Surgeons, London, December 1995.

Paper received 7 August 1996. Accepted 27 January 1997, after revision.