Tarsometatarsal (midfoot) injuries are relatively rare injuries. They make up 0.2% of all fractures. Despite their infrequent occurrence they can be quite debilitating. They range from mild, stable sprains to those with severe displacement and a high rate of associated injuries. The midfoot is normally highly stable secondary to its unique bony arrangement between the tarsal (3 cuneiforms and cuboid) and metatarsal bones and multiple strong ligaments. The midfoot is highly important to the overall stability and function of the lower extremity. These injuries most commonly occur in motor vehicle accidents, crush injuries, and twisting associated with falls. These injuries can be from direct blows or loads on a hyperflexed foot. One must have a high index of suspicion as 20-40% of these injuries are missed on initial exam. The male to female ratio is 2-4:1 and the average age is mid-30’s.
Pain and swelling in the midfoot are hallmarks of the condition but can vary based on the severity of injury. Severe injuries will reveal gross deformity. Instability may or may not be obvious. The severity of the injury will dictate whether a patient can bear weight on the foot. 1 in 5 will be open (compound) fractures. Associated injuries are found in approximately 80 % of patients. AP, Lateral, and Internal Oblique X-rays are mandatory and should be weight-bearing if possible. Some unstable injuries may spontaneously reduce and be missed on nonweight-bearing films. Stress X-rays or opposite foot X-rays are also occasionally needed to detect subtle instability. CT scans are frequently used to accurately assess joint damage and to assist with pre-operative planning. Fractures involving the 2nd metatarsal base are seen in approximately 90% of injuries.
The key to a successful outcome is an anatomic reduction. Studies suggest a 50-95% good to excellent result with an anatomic reduction versus 17-30% if anatomic alignment is not obtained. Open reduction and internal fixation (ORIF) is always needed for any unstable, subluxated, or dislocated injuries. Surgery is usually performed in the first 7-10 days as soft tissue swelling allows. Screws are placed across the first 3 tarsometatarsal joints to restore and maintain an anatomic reduction. K-wires are used across the 4th and 5th joints if needed for stability to minimize injury to the joints and maximize later motion.
Post-operatively patients are kept nonweight-bearing for 6-10 weeks. K-wires are removed after 6 weeks and the screws are removed at about 4 months to try and maximize midfoot motion. Physical therapy is usually started after the period of nonweight-bearing. Patients return to sedentary work by 4-6 weeks. It typically requires 5-6 months to return to jobs requiring prolonged standing, walking, climbing, or lifting. Many patients will return with some long term restrictions. Maximum medical improvement takes approximately one year. Patients require shoe modifications and/or orthotics to maximize function. 100% of patients will develop X-ray findings of arthritis which may or may not be symptomatic. Arthritis that can not be managed with anti-inflammatory medications, shoe modifications/orthotics, and activity modifications require midfoot fusions of the affected joints.
Many patients require permanent work restrictions and/or job changes. 50% of patients will have some permanent impairment. Post-traumatic arthritis can result in a PPI of 4% whole person, 10% lower extremity, 14% foot up to 8, 20, and 28%. A midfoot fusion results in a 4% whole person, 10% extremity, and 14% foot impairment.
Tarsometatarsal fracture-dislocations are relatively rare injuries that can lead to significant impairment and job limitations. The key to maximum recovery is a high index of suspicion as 20-40% of injuries are missed on initial exam and an anatomic surgical reduction performed by an orthopaedic foot and ankle specialist.