How To Treat Cuboid Syndrome In The Athlete
What One Should Look For
In The Physical Exam
When examining the affected foot of these patients, one can elicit pain by pressing dorsally on the plantar surface of the cuboid. Clinicians will find the cuboid’s minimal dorsal/plantar joint play is markedly reduced or absent when one compares it to the uninvolved foot. Severely subluxed cuboids can leave a shallow, visible depression on the dorsum of the cuboid and a fullness on the plantar aspect.
Be aware that diagnosing cuboid syndrome via radiographs, computerized axial tomography (CT) scans or magnetic resonance imaging (MRI) is difficult because of the normal variations that exist between the cuboid and its surrounding structures, and the minimal amount of subluxation that is usually present. The term “locked cuboid” may more accurately describe this condition. As this term suggests, a small subluxation can markedly reduce the normal motion in the midtarsal joint, thus altering both the normal mechanics and the relationship between the rearfoot and the forefoot.
The plantar displacement of the cuboid resulting in cuboid syndrome is most often reported in association with an inversion and plantarflexion stress of the ankle. It has been proposed that the mechanism of injury resulting in this isolated dislocation of the cuboid is due to rotation with associated inversion or eversion of the forefoot.
The ligamentous disruption results in displacement of the cuboid. The peroneus longus tendon that travels in the groove on the inferior surface of the cuboid exerts a dorsal and lateral force on the forefoot. This rotational force would close pack the cuboid in its articulations and force the bone in an inferomedial direction, tearing interosseous ligaments.
Another suggested mechanism is that the inversion stress at the ankle may cause a reflex contraction of the peroneus longus muscle in an attempt to restore balance and medial ground contact. This forceful contracture of the peroneus longus muscle creates a medial rotation of the cuboid. Then the peroneus longus tendon — within the osseous fibrous tunnel on the inferior surface of the cuboid — imparts a dorsal and lateral force on the cuboid, which results in the inferomedial subluxation. Disruption of the intertarsal ligaments may occur from the inversion force or when the cuboid is forcefully rotated.
Other Conditions To Consider During Diagnosis
There are many clinical conditions one must consider in the differential diagnosis of an athlete who presents with lateral foot pain (see “A Guide To Differential Diagnoses For Lateral Foot Pain” below).
If the athlete is an adolescent, one should have a strong index of suspicion for tarsal coalition, a condition that is most similar to cuboid syndrome. Both can present with the same, non-specific symptoms that usually occur after a minor injury such as a mild ankle sprain.
However, in the case of tarsal coalition, pain occurs in the subtalar or midtarsal area of the involved foot. It is aggravated by walking, prolonged standing, jumping or participating in athletics. Rest usually relieves the pain. In severe cases, the patient may present with an antalgic gait and have a significant limp.
Upon examination, those with a tarsal coalition will usually have a stiff foot with a significant decrease in subtalar joint motion. In these cases, one will often note a loss of the longitudinal arch, hindfoot valgus and forefoot abduction. Forced inversion of the foot will exacerbate the symptoms. Radiographs may or may not be helpful in making a definitive diagnosis. (See “Is Peroneal Spastic Flatfoot Causing Chronic Ankle Pain?” in the June 2002 issue of Podiatry Today.)
A Guide To Differential Diagnoses For Lateral Foot Pain
Sinus tarsi syndrome
Lateral process fracture of the talus
Acute tendinitis of the peroneus longus tendon
Fracture of the anterior process of the os calcis
Malalignment of the lateral ankle and subtalar joints
Fractures (including stress fractures)
Meniscoid of the ankle
Fracture or dislocation of the os peroneum
Inflammatory and noninflammatory arthritis
Tarsal coalitions (in adolescents)