Foot and Ankle cases 7

A 54-year-old woman presents to clinic reporting discomfort on the dorsum of her foot with shoewear and pain in the middle of her foot with activity, especially when she goes upstairs.

All but which of the following comprise the midfoot?

1. Second and third tarsometatarsal joints (TMTJs)

2. Subtalar joint

3. First TMTJ

4. Articulation between the navicular and cuneiforms

5. Fourth and fifth TMTJs

 

Discussion

The correct answer is (B). The subtalar joint is not part of the midfoot; it is part of the hindfoot. The remaining answers comprise portions of the midfoot.

She is interested in avoiding surgery for her midfoot arthritis and asks you what options she has for a type of shoe or orthotic that might alleviate her pain.

Your first suggestion would be:

1. Arizona brace

2. UCBL orthotic

3. Stiff-soled shoe with or without rocker bottom modification

4. Half-length carbon fiber insert

5. Budin splint

 

Discussion

The correct answer is (C). Stiff-soled shoes with rocker bottom modification have long been the initial nonoperative therapy for midfoot arthritis. Recently, in an effort to address the cumbersome nature of these shoes, exchangeable full-length carbon fiber inserts have been employed. Both are acceptable first-line treatments.

Half-length inserts are unlikely to span the affected joints and will not help in minimizing pain in the midfoot. The Arizona brace is typically used to address ankle or hindfoot arthritis. The UCBL is a stiff, custom orthotic that is used to address adult-acquired flatfoot disorder. It employs a deep heel cup to stabilize the hindfoot and a built-up lateral wall to address an abducted foot. The UCBL’s rigid medial arch may offer some midfoot pain relief but the UCBL is not a first-line treatment of midfoot arthritis. Budin splints are used to address hammertoes.

The patient returns the following year and reports that her pain has gradually worsened with nonsurgical management. Radiographic findings demonstrate arthritic changes, primarily at the second TMTJ (Fig. 5–14).

 

 

Figure 5–14 Weight-bearing AP radiograph of the foot demonstrating joint space narrowing at the second TMTJ with relative sparing of the first TMTJ.

 

Prior image-guided injection at the second TMTJ relieved the vast majority of her pain. She states that her pain is not limited to the “bumps at the top of her foot,” and is a deeper achy discomfort. You recommend a second TMTJ arthrodesis (Fig. 5–15).

 

 

Figure 5–15 Postoperative WB AP foot radiograph demonstrating second TMTJ arthrodesis, associated with 95% relief of pain.

 

When dealing with midfoot arthritis, which of the following pairings of location and surgical intervention is least appropriate?

1. Dorsal bossing with dorsal pain associated with shoewear only: exostectomy

2. 1–3 TMTJ arthritis: arthrodesis

3. 4–5 TMTJ arthritis: arthrodesis

4. 4–5 TMTJ arthritis: interpositional arthroplasty

 

Discussion

The correct answer is (C). Pain that is dorsally based and associated with pressure on prominences from shoewear may be addressed with exostectomy. Medial and midfoot arthritis that has failed nonoperative treatment is best addressed with arthrodesis. Range of motion in the sagittal plane at this location is around 7 degrees. However, lateral midfoot range of motion is approximately 20 degrees and lateral midfoot flexibility plans an important role in accommodating the ground. Accordingly, lateral midfoot arthrodesis is rarely recommended. If intervention is pursued for lateral midfoot arthritis, interpositional arthroplasty is often considered.

You are planning the surgical procedure at the beginning of the case and reviewing standard measurements and anatomical relationships. Which of the following is incorrect?

1. The second TMTJ is approximately 1 to 2 cm proximal to the first TMTJ

2. The first TMTJ is often between 2.5 and 3 cm deep

3. The distance from the tip of the hallux to the first metatarsophalangeal joint is nearly equivalent to that from the first MTPJ to the first TMTJ

4. On cross section, the midfoot is shaped like an arch with a dorsal apex

5. The second TMTJ is distal to the first and third TMTJs

 

Discussion

The correct answer is (E). The second TMTJ is proximal to the adjacent joints by approximately 1 to 2 cm. The remaining options are correct and can be valuable in planning surgical incisions. Of particular note is the depth of the first TMTJ (Fig. 5–16). Failure to fully prepare the plantar aspect of the TMTJs can lead to nonunion, partial union, or malunion.

 

 

Figure 5–16 Sagittal CT section of first TMTJ demonstrating joint space narrowing, cuneiform subchondral cyst and dorsal osteophytes with a measured depth of ~2.7 cm.

 

Objectives: Did you learn...?

 

Assess anatomic considerations about the midfoot (range of motion, osseous relationships, depth of first TMTJ)?

 

 

Describe nonsurgical treatment options for midfoot arthritis? Describe surgical options for midfoot arthritis?