Review Question - QID 4490

Plantar plate deficiency is most commonly associate with cross-over toe deformity, which is shown in Figure A.

The tendency with weight-bearing is to displace the proximal phalanx dorsally. The plantar plate and the intrinsic flexors (interossei and lumbricles) resist this force and pull the proximal phalanx back into a neutral position at the MTP joint. Chronic or acute hyperextension forces on the proximal phalanx cause stretching and/or attenuation of the plate, resulting in instability. Ultimately, this instability, in conjunction with collateral ligament attenuation, can lead to the clinical condition where the second toe crosses either under or over the hallux.

Shirzad et al. review the presentation, anatomy, and treatment of common lesser toe deformities. They specifically outline the nonsurgical and surgical treatment for MTP joint instability, such as that found in cross-over toe. Isolated soft-tissue procedures or osteotomies can be performed based on the degree of instability present and joint congruence.

Illustration A shows the plantar plate, and how laxity of this structure leads to MTP joint laxity and toe deformation.

Incorrect Answers:
Answer 2: This image shows the classic radiographic appearance of Freibergs infraction which is not associated with plantar plate pathology.
Answer 3: This clinical image shows a Lisfranc injury. This condition frequently occurs in the setting of acute trauma, and is not typically related to plantar plate deficiency.
Answer 4: This clinical image shows a classic claw-toe deformity of the second toe. This is caused by weaker intrinsic
forces which give way to the stronger extrinsic forces. MTP joint extension is caused by the action of the stronger EDL tendon on the extensor sling.
Answer 5: This clinical image shows a classic curly-toe deformity. This is caused by contracture of the FDL and FDB, the etiology of which is unknown.