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PathogenesisĪfter an injury, the midfoot may become unstable due a loss of the bony and ligamentous architecture. 10īecause the majority of patients with midfoot arthritis have had prior trauma, it is important to ask patients about any relevant trauma to the foot. 14 Flatfoot deformity may also be present 78% of patients complain of difficulty with shoe wear or unusual foot posture. This pain may be aggravated by activities that require the midfoot to be rigid, such as heel rise (walking up stairs) and walking on level surfaces. Patients with midfoot arthritis present with pain localized to the involved TMT joints. The Chopart joint is flexible during heel strike (increases efficiency of gastroc-soleous complex) and rigid during toe-off, which then transfers the forward movement through to the TMT joints. 22 In a Lisfranc injury, therefore, the dorsal ligaments are most likely to tear first, followed by the plantar ligaments and, finally, the Lisfranc ligament.ĭuring gait, the TMT joint complex and the Chopart joint (calcaneocuboid and talonavicular joint) allow for load transmission from the hind to the forefoot. Solan and colleagues evaluated the biomechanical characteristics of the midfoot ligaments, and they discovered that the dorsal ligaments are weaker than the plantar ligaments and that the Lisfranc ligament is the strongest. The saggital motion of each tarsometatarsal joint increases the more lateral in position (Table 1). The Lisfranc ligament itself runs from the second metatarsal base to the medial cuneiform. The oblique interosseous ligament, also known as the Lisfranc ligament, is the strongest and most robust of all the midfoot ligaments. Instead of a transverse ligament between the 1st and 2nd metatarsal, there are plantar, interosseous, and dorsal oblique ligaments that runs from the medial cuneiform and the base of the 2nd metatarsal. The transverse ligaments run plantarly and dorsally between the bases of the 2nd through 5th metatarsals.

2 The anatomic organization is divided into plantar, dorsal, oblique, transverse, and interosseous. The Lisfranc joint is further stabilized by many robust ligaments, as organized by dePalma et al. 15 Coronally, the bases of the 2nd, 3rd, and 4th metatarsals are trapezoidal and make up a “Roman arch” configuration which further enhances stability. This recess allows for the 2nd metatarsal to articulate with five osseous structures (which includes the three cuneiforms). The middle cuneiform is recessed by approximately 8 mm to 4 mm proximal to the medial and lateral cuneiforms, respectively. Its strength and stability is inherent in the bony and ligamentous anatomy. The Lisfranc joint complex structurally supports the transverse arch of the foot.

Indirect trauma may occur when there is unusual axial loading of the plantarflexed foot. High-energy trauma is usually directed to the dorsum of the foot with resultant significant soft tissue and bony crushing injuries. These injuries generally are caused by motor vehicle collisions (40-45%), followed by lower-energy mechanisms (30%).

5 The mechanisms for TMT joint complex injury are caused by either direct or indirect trauma. 11 Unfortunately, 20% of these injuries are misdiagnosed or undiagnosed at time of injury. Injury to the TMT complex occurs in 1 in 55,000 person per year in the United States, which accounts for 0.2% of all fractures. In the case of primary osteoarthritis, the 2nd and 3rd joints are most commonly involved.

12,19 The most common area of secondary midfoot arthritis is from Lisfranc injuries, resulting in degeneration of the 1st, 2nd, and 4rd TMT joints. Patients with secondary degeneration become symptomatic earlier than those with primary osteoarthritis, usually in the fourth decade as compared to the sixth decade. The most common cause of midfoot arthritis is post-traumatic arthritis, followed by primary osteoarthritis and other inflammatory processes. Tarsometatarsal (TMT) arthritis is a debilitating condition characterized by midfoot instability, severe functional impairment, and pain.