Foot and Ankle cases 41
A 21-year-old, collegiate football player noted acute medial forefoot pain when he axially loaded a dorsiflexed great toe and plantar-flexed ankle while blocking during a game. He noted gradual swelling and ecchymosis about his first metatarsophalangeal joint (MTPJ). He was unable to return to the game. He denies
pain near his midfoot. An AP foot radiograph is shown (Fig. 5–85).
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Figure 5–85 AP foot radiograph. Image courtesy of Tom Douglas, MD.
What is the most likely diagnosis?
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First MTPJ dislocation
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First MTPJ plantar plate rupture
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Hallux valgus
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Flexor hallucis longus (FHL) rupture
Discussion
The correct answer is (B). Plantar plate rupture, or “turf toe,” is associated with this mechanism of injury, radiographic findings, and associated disability. MTPJ dislocation and FHL rupture may occur with this mechanism, however, axial loading of a dorsiflexed or hyper-dorsiflexed first MTPJ is more frequently associated with turf toe. Hallux valgus may be encountered with a partial medial plantar plate rupture and/or displaced tibial sesamoid fracture but this would more commonly be seen radiographically with angular deformity.
When compared to a contralateral AP foot radiograph, what radiographic finding best supports the diagnosis of complete plantar plate rupture?
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Proximal migration of the sesamoids
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MTPJ dislocation
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Proximal phalanx fracture
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Increased hallux valgus angle
Discussion
The correct answer is (A). With avulsion of the plantar plate insertion from the proximal phalanx or tear through the mid-substance of the plantar plate, the sesamoids may retract proximally. This can be identified on films of the injured extremity (Fig. 5–85) and may be confirmed by obtaining comparison views of the contralateral, uninjured extremity. Alternatively, the injury may be associated with fracture of one or both sesamoids. If the diagnosis is not clear by plain radiograph (limited proximal migration, concern for bipartite sesamoid), an MRI may be obtained to evaluate disruption of the plantar plate. MTPJ dislocation would be more easily identified on lateral radiographs of the foot and would not likely require a contralateral AP view. Proximal phalanx fracture is less commonly associated with plantar plate rupture, although a small avulsion fleck(s) may be appreciated. Increased hallux valgus angle may be noted with injuries that are limited to the medial aspect of the plantar plate complex.
Your patient desires to return to football next year for his final college season.
What intervention might you recommend?
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First MTPJ arthrodesis
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First MTPJ cheilectomy
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Plantar plate repair
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Extensor hallucis transfer
Discussion
The correct answer is (C). With complete plantar plate rupture, especially in the high-level athlete, direct surgical repair is often recommended. This is typically performed with suture repair of the medial and lateral aspects of the plantar capsuloligamentous cuff (Figs. 5–86 and 5–87). If plantar plate rupture is associated with significant displacement of one or both fractured sesamoids, open reduction and internal fixation (ORIF) may be incorporated into the treatment plan. Alternatively, a sesamoid may be excised with repair of the surrounding soft tissue if ORIF is not feasible.
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Figure 5–86 Medial approach with sutures placed proximally and distally in plantar plate prior to approximation.
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Figure 5–87 AP radiograph demonstrates restoration of proper sesamoid position relative to the metatarsal head.
First MTPJ cheilectomy or arthrodesis is performed for hallux rigidus, which may be a delayed consequence of plantar plate rupture. However, this would not be appropriate for initial treatment. Extensor hallucis transfer is not the initial treatment for this injury. With loss of the plantar plate and flexor hallucis brevis complex, unopposed pull of the extensors, and flexor hallucis longus may result in the development of intrinsic minus of the hallux (cock-up toe).
Objectives: Did you learn...?
Describe the mechanism of injury for turf toe? Describe the relevance of sesamoid retraction? Identify indications for surgical repair?
Discuss reasons for development of intrinsic minus hallux with failed treatment?