Wednesday, February 1, 2012

Complex Midfoot Injury

A 24 year old fell awkwardly at a Fourth of July celebration, injuring her left foot. She presented to a local community hospital, where X-rays and a CT scan were obtained.
The plain X-rays showed evidence of a non-displaced fracture in one of the cuneiform bones.

The CT scan confirmed a fracture in the middle cuneiform, along with several small bone fragments suggestive of ligament injuries in the dorsal midfoot. A small about of subluxation is seen in the talonavicular joint.

She was placed in a boot type orthotic and instructed to keep her weight off of it. During the course of her follow-up, there was increasing displacement. Nine weeks after her fall, she was referred to the Orthopaedic Trauma Clinic at Harborview Medical Center, where the X-rays showed collapse of the midfoot.

At this point she was diagnosed with dislocation of the navicular at both the talo-navicualr and navicular-cuneiform joints. In contrast to the navicular-cuneiform joints, which are very stable joints without motion, the talo-navicular joint is a mobile joint, known in the foot as an “essential joint”. The architecture of this part of the foot, as well as the motion in the essential joints, contributes to the painless function of the foot. Surgery was indicated to restore the anatomic relationships of the midfoot, and to provide for normal motion in the talonavicular joint.

She underwent an open reduction of the navicular-cuneiform joints, which realigned the talo-navicular joint.

In addition, a stress X-ray was taken in the operating room, and demonstrated significant instability at the first tarso-metatarsal joint, a normally stable articulation. It is important when treating midfoot injuries to identify all sites of instability, some of which may not be immediately apparent. Stress X-rays are helpful in identifiying unstable joints, which may be injured but not significantly displaced. These are typically treated so that displacement will not occur once normal activity is resumed.

The Xrays after surgery show that the stable midfoot joints, the navicular-cuneiform, and tarso-metatarsal, have been reduced and stabilized with several plates, multiple screws, and Kirschner wires. At the same time, the talonavicular joint has been reduced and will stay reduced as long as the stable joints remain reduced.

Nine months after her surgery, she is walking unlimited distances with minimal pain. Once the stable joints have healed more completely, the hardware can be removed if desired.

Midfoot injuries can be challenging to diagnose. Once diagnosed, the goals of treatment are to restore and maintain the normal relationships of the bones. Stable joints must heal solidly, and essential joints must have motion spared in order to optimize the functional outcome.

Authored By: James Krieg, MD