How To Conquer Crossover Second Toe Syndrome

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Insights On Grading Crossover Second Toe Syndrome

A grading system is essential in considering complaints associated with the deformity and arriving at proper treatment options. I have started to grade the crossover second toe prior to the toe actually crossing the hallux. In fact, my grading system considers the function of the plantar plate as the essential factor in assessing crossover second toe syndrome. As the grade level increases, the level of pain associated with the plantar plate decreases. This is mainly due to the fact that the partial rupture of the plantar plate progresses to a complete rupture.

• Grade I: No gross deformity with pain on the plantar second MPJ and no dorsal drawer sign noted.

• Grade II: Minimal medial deviation of the second toe with associated pain plantar to the second MPJ and a positive dorsal drawer sign. You’ll also see increased radiographic joint space of the lateral second MPJ in comparison to the medial aspect of the second MPJ. There may also be a possible hallux valgus deformity.

• Grade III: Dorsal displacement of the second toe at the MPJ with slight abutment or minimal crossover of the second toe dorsal to the hallux. The patient may have pain or no pain on the plantar surface of the second MPJ and a positive drawer sign. In addition to seeing an increased radiographic joint space on an antero-posterior radiograph of the lateral second MPJ with medial deviation of the second toe, a hallux valgus deformity is probable in these cases.

• Grade IV: Dislocation of the second MPJ with complete overriding second toe. The patient may have pain or no pain, but will usually have a hallux valgus deformity.

Here is a preoperative view of the crossover second toe, which has a complex etiology, according to the author.
Here is a typical radiograph of crossover second toe syndrome. Note the long second metatarsal and deviation of the second toe.
Here is an MRI that reveals a torn plantar plate with a fleck fracture from the base of the metatarsal.
Here is a surgical example of metatarsal osteotomy, flexor tendon transfer and fusion of the proximal interphalangeal joint.
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Author(s): 
By Babak Baravarian, DPM

The crossover second toe is an extremely difficult problem for foot and ankle surgeons. Often, with the initial presentation, the deformity has progressed to the point where it is one subsection of a multitude of forefoot deformities. This makes the condition more challenging as you must treat the associated deformities at the same time in order to achieve a good outcome.
The etiology of crossover second toe syndrome is not fully understood. Although multiple theories have been suggested, the true underlying cause of the deformity is multifactorial and only some of these factors have been scientifically studied.
What is clear about the underlying deformity is an imbalance between the pull and position of the flexor and extensor apparatus. In a cadaveric dissection study done by Deland and Sung, the medial crossover second toe deformity was associated with an abnormal position of the long and short flexor tendons on the involved foot versus central position of the flexor tendons in the uninvolved foot.1 They found the flexor tendons to be medially deviated and sitting very close to the first interspace region.

Furthermore, Deland noted the plantar plate was medially and distally deviated on the plantar surface of the joint line. The researchers also noted poor continuity and thickness of the lateral plantar plate attachment to the proximal phalynx base.
Multiple studies have noted a second factor contributing to the deformity is a tear of the lateral collateral ligament structures.2-4, 6 The collateral ligament tears may include the metatarsophalangeal joint (MPJ) collateral, the accessory collateral which attaches to the plantar plate, or in most cases, both lateral collateral structures. With time, a shortening and overpowering of the medial collateral ligaments aggravates the underlying problem.
Although it’s essential to consider soft tissue deformity in such cases, there is a great deal of interest in the osseous deformity associated with crossover second toes. Inevitably, those who treat the condition commonly note there is a long metatarsal associated with the deformity. We must consider metatarsal length and possible wear and tear to the plantar soft tissue structures associated with prolonged periods of high peak pressures during gait.
A second area of concern is hypermobility of the first ray in association with high peak pressures plantar to the second metatarsal head region. It is possible that in those patients with laxity at the metatarso-cuneiform joint, there is poor plantar pressure distribution on the medial aspect of the foot resulting in high peak pressure values plantar to the second metatarsal head. Even in cases of hallux valgus deformity with minimal instability at the metatarso-cuneiform joint, there may be a decrease in direct pressure plantar to the first MPJ, resulting in increased peak pressure distribution plantar to the second MPJ capsule. This direct pressure coupled with adductus of the hallux, which may cause dorsal displacement of the second toe, may be one of the underlying causes of the crossover second toe.

Looking For Common Causes In Crossover Toe Cases
Presently, there is not one accepted cause for the problem of crossover toe. My impression is the problem often, if not always, involves a long second metatarsal, resulting in increased peak values plantar to the second MPJ. In most cases, surgeons note an associated hallux valgus deformity as well. This deformity is far worse in cases of severe crossover second toe deformity. However, since the problem does not present in its initial phase very often, it is difficult to consider if the hallux valgus deformity contributed to the cause or if the poor buttress function of the second toe resulted in the hallux valgus deformity increasing in severity.

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