Foot and Ankle cases 15
A 52-year-old female presents to you reporting left foot pain that has been present for the past 3 months. She describes discomfort over the medial hindfoot region, which began without a traumatic inciting event. Her pain is minimal in the morning, however becomes progressively worse after extended walking and standing. She has worn inserts in her shoes for many years due to “low arches.” Physical examination reveals a flexible valgus hindfoot, with midfoot abduction, and forefoot supination. The patient has tenderness and swelling along the posterior tibial tendon, and difficulty with single-limb rise. Radiographs of the foot and ankle are obtained (Fig. 5–28A–C).
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Figure 5–28 A–C: Initial foot and ankle radiographs.
Which muscle is the functional antagonist to the posterior tibial tendon?
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Achilles
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Gastrocnemius
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Peroneus brevis
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Peroneus longus
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Peroneus tertius
Discussion
The correct answer is (C). The posterior tibialis muscle is a component of the deep posterior compartment of the leg. The posterior tibial tendon (PTT) courses along the posterior border of the medial malleolus, along with the flexor digitorum longus, posterior tibial neurovascular bundle, and flexor hallucis longus tendon. The PTT broadly attaches to the navicular, and functions to invert the hindfoot, which functionally locks the transverse tarsal joints (talonavicular and calcaneocuboid joints) and plantarflexes the ankle. This locking motion allows for a rigid lever during the push off phase of gait. The peroneus brevis is the functional antagonist to the PTT and acts to evert the hindfoot. The tibialis anterior and peroneus longus are functional antagonists to one another.
The patient was previously seen by another physician who ordered an MRI of the ankle (Fig. 5–29A–C).
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Figure 5–29 A–C: MRI images of the ankle.
Appropriate initial conservative treatment for this patient might include activity modification, nonsteroidal anti-inflammatories, and which of the following?
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Extra-depth shoes
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Metatarsal bar
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Ankle compression sleeve
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Night splint
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Arizona brace
Discussion
The correct answer is (E). The patient has stage 2 posterior tibial tendon deficiency (PTTD). Stage 1 PTTD includes tenosynovitis of the PTT without degeneration or deformity. Stage 2 PTTD is a flexible planovalgus deformity, which is passively correctable. MRI images show longitudinal split tearing and tendinopathy of the PTT, consistent with this finding. Stage 3 PTTD is a rigid flatfoot deformity, while stage 4 includes involvement of the tibiotalar joint as well as the foot. Initial conservative treatment for stage 2 PTTD can be with the use of an Arizona brace. A night splint would be more appropriate for the treatment of plantar fasciitis, and an ankle compression sleeve might be for lower extremity edema.
The patient returns to clinic after 6 months of conservative treatment, and continues to report pain in the medial hindfoot. She would like to discuss surgical treatment options.
The recommended surgical treatment would include:
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Posterior tibial tendon debridement
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Posterior tibial tendon debridement, flexor digitorum longus tendon transfer
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Posterior tibial tendon debridement, flexor digitorum longus tendon transfer, and lateralizing calcaneal osteotomy
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Posterior tibial tendon debridement, flexor digitorum longus tendon transfer, medializing calcaneal osteotomy, and first ray plantar flexion osteotomy
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Triple arthrodesis
Discussion
The correct answer is (D). The surgical treatment for stage 2 PTTD should include both soft tissue reconstruction and joint-preserving bone realignment with osteotomies. Posterior tibial tendon debridement alone does not correct deformity, and transfer of the FDL tendon to the navicular without addressing mal-alignment predisposes to failure of the reconstruction. Based upon the degree of correction required, calcaneal osteotomies may include a medial slide osteotomy, lateral
column lengthening osteotomy, or both. Residual forefoot supination should be addressed with a plantar flexion osteotomy of the first ray, traditionally with an opening wedge osteotomy of the medial cuneiform (Cotton osteotomy). Triple arthrodesis would be performed for rigid PTTD (stage 3). In all cases of PTTD, the Achilles and gastrocnemius should be examined for a contracture using the Silfverskiold test. This would additionally be addressed at the time of surgery with a tendo-Achilles lengthening or Strayer/gastrocnemius lengthening in the same surgical setting.
Objectives: Did you learn...?
Describe the anatomy of the medial ankle/hindfoot?
Identify the function and mechanics of the posterior tibial tendon? Assess nonsurgical and surgical treatment of PTTD