Dorsal Approach to the Metatarsophalangeal Joints of the Second, Third, Fourth, and Fifth Toes

Dorsal Approach to the Metatarsophalangeal Joints of the Second, Third, Fourth, and Fifth Toes‌

 

 

The dorsal approach, which exposes the metatarsophalangeal joints of the second, third, fourth, and fifth toes, avoids incision of the plantar skin of the foot. Most plantar approaches scar the weight-bearing skin, violating a basic surgical principle.

The uses for the approach include the following:

1. Excision of metatarsal heads

2. Distal metatarsal osteotomy

3. Partial proximal phalangectomy

4. Fusion of metatarsophalangeal joints (rare)

5. Capsulotomy of metatarsophalangeal joints

6. Muscle tenotomy

7. Neurectomy

 

Position of the Patient

 

Place the patient supine on the operating table. Position a bolster under the thigh to flex the knee and allow the foot to lie with its plantar surface on the table (Fig. 12-81).

Landmarks and Incision

Landmarks

To palpate each metatarsal head, place a thumb on the plantar surface and an index finger on the dorsal surface of the foot. Skin callosities under the heads indicate that the area concerned is bearing an unaccustomed amount of weight and indicating pathology in the weight distribution around the foot. Palpate the tendons of the extensor digitorum longus muscle on the dorsal aspect of the foot.

Incision

Make a 2- to 3-cm longitudinal incision over the dorsolateral aspect of the affected metatarsophalangeal joint. The incision should run parallel with, but just lateral to, the long extensor tendon (Fig. 12-82). If two adjacent joints need to be exposed, make the incision between them. Alternatively, a transverse dorsal incision may be made over the joints.

 

 

Figure 12-81 Position of the patient for approaches to the toes.

 

 

Figure 12-82 Make a 2- to 3-cm longitudinal incision over the dorsolateral aspect of the affected metatarsophalangeal joint.

 

Internervous Plane

 

There is no true internervous plane for any of these metatarsophalangeal approaches. The approaches are well dorsal to the plantar nerves and vessels, the key neurovascular structures in this area. Take care to avoid cutting the dorsal digital nerves, branches of which may cross the operative field.

 

Superficial Surgical Dissection

 

Incise the deep fascia in line with the incision, and retract the long extensor tendon to reveal the dorsal aspect of the metatarsophalangeal joint (Fig. 12-83). Often, an extensor tenotomy or lengthening is performed at the same time as the operation on the joint. In this case, divide the extensor

tendon in a “Z” fashion rather than retracting it. If two joints are being exposed, retract the tendon laterally to gain access to the adjacent joint.

 

Deep Surgical Dissection

 

Incise the dorsal capsule of the metatarsophalangeal joint longitudinally to enter the joint (Figs. 12-84 and 12-85).

 

 

Dang

 

 

The long extensor tendon should be protected during the procedure.

At the level of the metatarsophalangeal joints, the plantar nerves and vessel lie between the metatarsal heads, beneath the deep transverse metatarsal ligament. As long as the dissection remains on the dorsal aspect of the ligaments, the nerves are safe. Dissection around the metatarsal heads and proximal phalanges must be carried out so as to avoid damage to the nerves and vessel that supply the weight-bearing skin of the toes (see Fig. 12-58).

 

 

 

Figure 12-83 Incise the deep fascia in line with the incision on the medial side of the long extensor tendon.

 

 

Figure 12-84 Expose the dorsal capsule of the metatarsophalangeal joint. Make a longitudinal incision into the capsule.

 

 

 

Figure 12-85 Retract the joint capsule to expose the metatarsophalangeal joint.