Brirish Journal of Plastic Surgery (I 986) 39,249-254 0 1986 The Trustees of British Association of Plastic Surgeons

Knee joint salvage utilising a plantar musculocutaneous pedicle flap

island

J. C. HAMM, T. R. STEVENSON and S. J. MATHES

Section of Plastic Surgery, Ann Arbor, Michigan

Summary-A young adult male presented with an open tibia-fibula fracture, extensive circumferential soft tissue loss and exposed bone. Although the fracture sites were stabilised by an external fixator, chronic infection complicated this 2-week-old wound. Treatment by amputation was elected. Local skin alone was inadequate for coverage of a preferred below-knee amputation. As an alternative to above-knee amputation, the patient underwent coverage of a below-knee amputation using a musculocutaneous island pedicle flap of sensate plantar skin and muscle.

Management of an open tibia-fibula fracture with massive soft tissue loss and chronic infection is dif- ficult, sometimes requiring amputation. A below- knee amputation with preservation of the knee joint is more desirable than an above-knee ampu- tation. We herein report the case of a patient with such an injury and the salvage of his knee using otherwise discarded tissue.

Case report

On October 10, 1984, a 20-year-old white male was involved in a motorcycle accident. He sustained an open right tibia-fibula fracture with extensive soft tissue avul- sion from the popliteal crease to the ankle. Plantar skin and sensation were preserved. Twenty centimetres of tibia denuded of periosteum were exposed. He under- went aggressive debridement of his right leg wound and external fixation with a Hoffmann device. The wound was treated with daily dressing changes. Fifteen days fol- lowing injury he was transferred to the University of Michigan Medical Center where heavy pseudomonas infection of his open fracture site was noted (Fig. 1). Arteriography demonstrated an intact posterior tibia1 artery (Fig. 2). A multistaged programme of reconstruc- tive procedures was planned consisting of initial wound debridement and muscle flap transplantation followed later by vascularised bone grafting procedures. The patient requested amputation and immediate rehabili- tation with a prosthesis rather than continued efforts to- wards limb salvage.

Despite absence of local skin for stump coverage, a below-knee amputation was planned utilising the intact plantar skin with intrinsic foot muscles as a composite transposition flap for stump coverage (Fig. 3). At the time of operation, the plantar soft tissue was removed as

a musculocutaneous unit incorporating the abductor hallucis, the abductor digiti minimi and the flexor digi- torum brevis muscles with their overlying skin (Figs. 4 and 5). This musculocutaneous unit was nourished and innervated by the posterior tibia1 artery, veins and nerve. The neurovascular pedicle was dissected proximally to the level of the tibia1 tubercle. A below-knee amputation was performed preserving 8 cm of tibia distal to the tibia1 tubercle. The neurovascular pedicle was arranged along the lateral and medial aspects of the tibia and the plantar musculocutaneous unit was positioned to cover the anterior and inferior portions of exposed tibia (Fig. 6). Posteriorly, the exposed gastrocnemius muscles were covered with split-thickness skin grafts.

Postoperatively, plantar sensation was preserved and the patient recovered uneventfully (Figs. 7 and 8). Amputation stump oedema subsided and he was placed on a vigorous programme of inpatient physical therapy. He has been fitted for a prosthesis and ambulation begun.

Discussion

This patient demonstrates salvage of a knee joint and avoidance of above-knee amputation using the available vascularised, innervated plantar muscu- locutaneous flap. Our decision to employ this flap was based on certain principles of muscle transpo- sition (Mathes et al., 1974). First, the flap must be large enough to cover the intended defect. The plantar surface was adequate for coverage of the exposed anterior tibia1 area. Second, the principal arterial source and venous return must be located in such a way that flap transposition will not inter- fere with vascular inflow or outflow.

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250 BRITISH JOURNAL OF PLASTIC SURGERY

Fig1 pate

Fig. 1 Fig. 2

ure I-Open tibia-fibula fracture in Hoffman external fixator. Figure 3-Arteriogram showing right tibia-tibula fracture :nt posterior tibia1 artery.

and

This was satisfied by maintaining the posterior tibia1 neurovascular pedicle. Third, the muscle for transposition should be expendable. This require- ment was obviously fulfilled in the patient pre- sented.

The posterior tibia1 neurovascular pedicle nourished and innervated this plantar unit. Blood supply to the plantar musculature and skin has been well described (Mathes and Nahai, 1979; Shanahan and Gingrass, 1979; Hartrampf et al., 1980; Reiffel and McCarthy, 1980; Skef et al..

1983). Calcaneal nerves emanating from the tibia1 nerve run with the calcaneal vessels and pierce the plantar fascia to supply the overlying heel skin.

This plantar musculocutaneous neurosensory flap has applicability either as a free flap (Manktelow, 1984) or as a pedicled island flap for coverage of lower extremity soft tissue defects when amputations of the foot are anticipated. The unique, durable characteristics of plantar skin should find utility in coverage of areas destined to bear weight or withstand pressure forces.

KNEE JOINT SALVAGE UTILISING A PLANTAR MUSCULOCUTANEOUS ISLAND PEDICLE FLAP 251

Fig. 3

Figure 3-Diagrammatic representation of innervated plantar musculocutaneous unit based on the posterior tibia1 vessels and nerve. The plantar skin and muscle flap is rotated 180” before insetting, placing turn of heel (A) in anterior and superior posi- tion.

Fig. 4

Figure 4-Plantar musculocutaneous neurosensory unit outlined.

252 BRITISH JOURNAL OF PLASTIC SURGERY

Fig. 5

Figure 5-Plantar musculcutaneous unit alongside tibia1 fracture with intact neurovascular pedicle prior to below-knee amputation.

Fig. 6

Figure &Flap inset over area of tibia1 tubercle with adjacent skin graft over medially transposed segment of medial gastrocnemius muscle.

KNEE JOINT SALVAGE UTILISING A PLANTAR MUSCULOCUTANEOUS ISLAND PEDICLE FLAP 253

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Fig. 7

Figure 7-Healed amputation stump, anterior view, 3 months postoperatively.

Figure 8-Amputation stump, lateral.

Fig. 8

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References

Hnrtrampf, C. R., Scheflan, M. and Fbstwick, J. (1980). The flexor digitorum brevis muscle island pedicle flap: a new dimension in heel reconstruction. Plastic und Reconstructive Surgery. 66,264.

Mankteiow, Ralph T. (1984). Personal communication. Mathes, S. J., MeCraw, J. B. and Vascowz, L. 0. (1974).

Muscle transposition flaps for coverage of lower extremity de- fects. Surgical Clinics of North America, 54, 1337.

Mathes, S. J. and Nahai, F. (1979). Clinical Atlas of Muscle and Musculocutaneous Flaps. St. Louis: Mosby.

Reiffel. R. S. and McCarthv. J. G. (1980). Coverage of heel and sole’defects: a new subkscial arterialized fla;. Plustic and Reconstructive Surgery, 66, 150.

Shanahan, R. E. and Gingrass, R. P. (1979). Medial plantar sen- sory flap for coverage of heel defects. Plastic and Reconsrruc- tive Surgery, 64,295.

Skef, Z., Ecker, H. A. and Graham, W. P. (1983). Heel coverage by a plantar myocutaneous island pedicle flap. Journal of Trauma, 23.466.

The Authors

Jeffrey C. Hamm, MD, Instructor. Thomas R. Stevenson, MD, Assistant Professor, Surgery Stephen J. Mathes, MD, Professor and Head.

Section of Plastic Surgery. Ann Arbor, Michigan.

Requests for reprints to: Thomas R. Stevenson, MD, Section of Plastic Surgery, C7200 Outpatient Building, University Hospi- tal, Ann Arbor, Michigan 48109, USA.