History and Physical Examination
Corns
The simplest of the fifth-toe deformities are corns—namely, the hard corn (heloma durum) and the soft corn (heloma molle). Both lesions are epidermal hyperkeratoses resulting from frictional or pressure irritation. They develop over bony prominences, such as enlarged phalangeal condyles or exostosis.
Hard corns
Hard corns result from intrinsic pressure from a bony prominence combined with extrinsic pressure (typically in the form of footwear irritation) over the exposed fifth toe. The most common site is the dorsal lateral aspect of the proximal interphalangeal (PIP) joint (PIPJ), but corns can also occur in the same location over the distal interphalangeal (DIP) joint (DIPJ) (see the image below). [6]
Fifth-toe deformities. Example of hard corn. They commonly occur on dorsal lateral aspect of proximal interphalangeal joint but can also occur in same location over distal interphalangeal joint.
The corn is typically associated with a hammertoe deformity (dorsiflexion contracture at the metatarsophalangeal [MTP] joint [MTPJ] and plantarflexion contracture at the PIPJ) that may have a varus rotational contracture. This makes the dorsal lateral aspect of the PIPJ more prominent and susceptible to footwear irritation. The corn can be superficial or deeply seeded; the latter is more painful. Additionally, constant pressure may cause a painful bursa to develop deep in the lesion, leading to nerve entrapment and increased pain.
In the neuropathic population, hard corns that go untreated can develop into ulcerations that lead to soft-tissue and bone infection.
Soft corns
Soft corns develop between adjacent toes. Intrinsic pressure develops between adjacent condyles of the lateral fourth PIPJ abutting the medial fifth DIPJ or between adjacent condyles the lateral fourth MTPJ abutting the medial fifth PIPJ. The lesions can develop on the skin at the lateral fourth PIPJ, the medial fifth DIPJ, the medial fifth PIPJ, or deep in the web space (see the image below).
Fifth-toe deformities. Example of soft corn deep in web space. Intrinsic pressure develops between adjacent condyles of lateral fourth proximal interphalangeal (PIP) joint (PIPJ) abutting medial fifth distal interphalangeal (DIP) joint (DIPJ), or lateral fourth metatarsophalangeal (MTP) joint MTPJ) abutting medial fifth PIPJ. Lesions can develop on skin over lateral fourth PIPJ, medial fifth DIPJ, medial fifth PIPJ, or deep in web space.
Kissing corns
Kissing corns are two calluses rubbing against each other on adjacent toes (see the first and second images below). Kissing corns are usually painful when the toes are squeezed together. Maceration is often noted in the web space and may contribute to the development of kissing corns (see the third and fourth images below). When they occur, other common problems, such as fungal infections or verruca, must be ruled out. If left untreated, these lesions may also develop into ulcerations in patients with neuropathy.
Fifth-toe deformities. This image and image below are examples of kissing corns. They are two calluses that rub against each other on adjacent toes and are usually painful when squeezed together.
Fifth-toe deformities. Example of kissing corn. These corns are two calluses that rub against each other on adjacent toes and are usually painful when squeezed together.
Fifth-toe deformities. This image and image below are further examples of kissing corns. Maceration is often noted in web space and may contribute to their development. When they occur, other common problems, such as fungal infections or verruca, must be ruled out. These lesions may develop into ulcerations in neuropathic population if untreated, as is seen in this case.
Fifth-toe deformities. Example of kissing corns. Maceration is often noted in web space and may contribute to their development. When they occur, other common problems, such as fungal infections or verruca, must be excluded. These lesions may develop into ulcerations in neuropathic population if untreated, as is seen in this case.
Hammertoe, claw-toe, and cock-up deformities
Hammertoe, [7, 8, 3] claw-toe, [9] and cockup deformities are all variations of the same problem. [10] The presence of a dorsiflexion contracture at the MTPJ and a plantarflexion contracture at the PIPJ is constant among the three (see the image below). The claw-toe deformity has the addition of a plantarflexion contracture at the DIPJ. The term cockup deformity is typically used to describe a severe hammertoe, in which the proximal phalanx articulates at a nearly 90° angle to the fifth metatarsal and may be fixed in that position. A cockup deformity can also be associated with plantar-plate ruptures or adhesions between the plantar MTPJ capsule and the metatarsal head.
Fifth-toe deformities. Example of hammertoe with dorsiflexion contracture at metatarsophalangeal joint and plantarflexion contracture at proximal interphalangeal joint. Note irritated skin secondary to shoe pressure.
Contractures can develop for several reasons; however, they most frequently occur because of mechanical imbalances. The intrinsic foot musculature fails to stabilize the fifth toe at the MTPJ, the PIPJ, and the DIPJ, allowing the more powerful extrinsic flexors and extensors to act unchecked. This eventually leads to the deformities described above.
Overlapping and underlapping fifth toes
Unlike the other conditions mentioned, overlapping and underlapping fifth toes are usually congenital deformities. [11] The overlapping fifth toe is a common familial deformity with equal sex predilection and usually presents bilaterally (see the images below). About half of patients become symptomatic because of pressure from footwear against the dorsal aspect of the toe and nail. The toe is dorsally hyperextended at the MTPJ with a varus rotation and medial deviation onto the top of the fourth digit.
Fifth-toe deformities. This image and image below represent an overlapping fifth toe. It is dorsally hyperextended at metatarsophalangeal (MTP) joint (MTPJ) with varus rotation and medial deviation onto top of fourth digit. Contractures develop dorsomedially at MTPJ and eventually form in extensor digitorum longus tendon and dorsomedial skin overlying MTPJ.
Fifth-toe deformities. Overlapping fifth toe is dorsally hyperextended at metatarsophalangeal (MTP) joint (MTPJ) with varus rotation and medial deviation onto top of fourth digit. Contractures develop dorsomedially at MTPJ and eventually form in extensor digitorum longus tendon and dorsomedial skin overlying MTPJ.
Contractures develop dorsomedially at the MTPJ and eventually form in the extensor digitorum longus (EDL) tendon and the dorsomedial skin overlying the MTPJ.
The underlapping fifth toe is another common congenital deformity, often referred to as curly toe or congenital varus toe (see the images below). This deformity may also occur bilaterally and has a high familial prevalence. The toe is plantarflexed at the MTPJ, rotated into a varus position, and positioned under the fourth digit. A contracture typically occurs at the plantar-medial MTPJ capsule and flexor digitorum longus (FDL) tendon. These are paired with an elongated EDL and an attenuated dorsal capsule. Constant pressure at the lateral nail and digital skin creates pain.
Fifth-toe deformities. This image and image below are examples of underlapping fifth toe, or curly toe. It is plantarflexed at metatarsophalangeal (MTP) joint (MTPJ), rotated into varus position, and positioned under fourth digit. Contracture typically occurs at the plantar-medial MTPJ capsule and flexor digitorum longus tendon.
Fifth-toe deformities. Underlapping fifth toe, or curly toe. It is plantarflexed at metatarsophalangeal (MTP) joint (MTPJ), rotated into varus position, and positioned under fourth digit. Contracture typically occurs at plantar-medial metataMTPJ capsule and flexor digitorum longus tendon.
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Fifth-toe deformities. Example of hard corn. They commonly occur on dorsal lateral aspect of proximal interphalangeal joint but can also occur in same location over distal interphalangeal joint.
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Fifth-toe deformities. Example of soft corn deep in web space. Intrinsic pressure develops between adjacent condyles of lateral fourth proximal interphalangeal (PIP) joint (PIPJ) abutting medial fifth distal interphalangeal (DIP) joint (DIPJ), or lateral fourth metatarsophalangeal (MTP) joint MTPJ) abutting medial fifth PIPJ. Lesions can develop on skin over lateral fourth PIPJ, medial fifth DIPJ, medial fifth PIPJ, or deep in web space.
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Fifth-toe deformities. This image and image below are examples of kissing corns. They are two calluses that rub against each other on adjacent toes and are usually painful when squeezed together.
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Fifth-toe deformities. Example of kissing corn. These corns are two calluses that rub against each other on adjacent toes and are usually painful when squeezed together.
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Fifth-toe deformities. This image and image below are further examples of kissing corns. Maceration is often noted in web space and may contribute to their development. When they occur, other common problems, such as fungal infections or verruca, must be ruled out. These lesions may develop into ulcerations in neuropathic population if untreated, as is seen in this case.
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Fifth-toe deformities. Example of kissing corns. Maceration is often noted in web space and may contribute to their development. When they occur, other common problems, such as fungal infections or verruca, must be excluded. These lesions may develop into ulcerations in neuropathic population if untreated, as is seen in this case.
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Fifth-toe deformities. Example of hammertoe with dorsiflexion contracture at metatarsophalangeal joint and plantarflexion contracture at proximal interphalangeal joint. Note irritated skin secondary to shoe pressure.
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Fifth-toe deformities. This image and image below represent an overlapping fifth toe. It is dorsally hyperextended at metatarsophalangeal (MTP) joint (MTPJ) with varus rotation and medial deviation onto top of fourth digit. Contractures develop dorsomedially at MTPJ and eventually form in extensor digitorum longus tendon and dorsomedial skin overlying MTPJ.
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Fifth-toe deformities. Overlapping fifth toe is dorsally hyperextended at metatarsophalangeal (MTP) joint (MTPJ) with varus rotation and medial deviation onto top of fourth digit. Contractures develop dorsomedially at MTPJ and eventually form in extensor digitorum longus tendon and dorsomedial skin overlying MTPJ.
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Fifth-toe deformities. This image and image below are examples of underlapping fifth toe, or curly toe. It is plantarflexed at metatarsophalangeal (MTP) joint (MTPJ), rotated into varus position, and positioned under fourth digit. Contracture typically occurs at the plantar-medial MTPJ capsule and flexor digitorum longus tendon.
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Fifth-toe deformities. Underlapping fifth toe, or curly toe. It is plantarflexed at metatarsophalangeal (MTP) joint (MTPJ), rotated into varus position, and positioned under fourth digit. Contracture typically occurs at plantar-medial metataMTPJ capsule and flexor digitorum longus tendon.
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Fifth-toe deformities. This radiograph shows prominent fifth-toe proximal phalanx medial condyle contacting base of proximal phalanx on fourth toe, creating increased pressure and interdigital clavi.
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Fifth-toe deformities. This radiograph shows distal phalanx of varus-rotated fifth toe contacting proximal phalanx on fourth toe, creating another area of increased pressure and interdigital clavi.
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Fifth-toe deformities. This image and following three images demonstrate surgical course for severe fifth digit cock-up deformity. Note dorsal contracture in this preoperative photo.
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Fifth-toe deformities. Planned incision with arms for Z-plasty skin-lengthening flap drawn in. Central arm of Z-plasty is along line of skin contracture.
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Fifth-toe deformities. Exposure showing severely contracted extensor digitorum longus tendon. This is lengthened during procedure.
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Fifth-toe deformities. Postoperative photo showing corrected fifth digit.
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Fifth-toe deformities. This image and following images demonstrate operative technique for painful overlapping fifth-toe deformity.
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Fifth-toe deformities. Painful overlapping fifth-toe deformity.
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Fifth-toe deformities. When toe is derotated and plantarflexed into correct position, dorsal skin "tents up," showing exact location of skin contracture.
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Fifth-toe deformities. In this case, Z-plasty is performed to lengthen contracted skin. Length is achieved along central arm of the "Z" so it is placed along the line of contracture. Adjunctive procedures such as metatarsophalangeal joint release and extensor digitorum longus tendon lengthening should be performed through same incision. Alternative to Z-plasty is V-Y flap.
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Fifth-toe deformities. After rotation of Z flaps and soft-tissue release, toe is reevaluated. Toe is down, and proximal phalanx is in excellent position, but distal portion of toe has varus rotation at proximal interphalangeal (PIP) joint (PIPJ). PIPJ arthroplasty with derotational skin plasty is then performed to address this portion of deformity.
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Fifth-toe deformities. This image and image below were taken 5 days postoperatively with contractures addressed and toe in good position.
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Fifth-toe deformities. Five days after surgery, contracture is addressed and toe is in good position.
