Metatarsus Adductus - Overview

What Is Metatarsus Adductus?

A deformity of the metatarsus that occurs only in the transverse plane of the foot is known as the metatarsus adductus. It can be described as a medial deviation of the forefoot at the tarsometatarsal joints or an adduction deformity of the forefoot concerning the hindfoot. This happens in conjunction with a contraction of the soft tissues. Due to the large styloid process and the convex lateral border of the foot, the foot is shaped like the letter C. In most cases, the deformity is modest, flexible, and self-correcting; nonetheless, therapy may be necessary for deformities ranging from moderate to severe.

What Are the Causes?

There is no specific reason that can be attributed to the development of the metatarsus adductus. However, there are several potential contributors that increase the risk. The following are some of the factors that are related to it:

• Familial Disorder: The condition manifests itself more frequently in a particular family than in the broader community. However, a family history of metatarsus adductus is common.

• Position of the Baby in the Uterus: The positioning of the fetus within the uterus, one of the most important factors in this process, has a considerable influence on the rotational alignment of the legs. At the seventh week of gestation, the lower limb begins to rotate medially (internally), followed by the upper leg rotating externally. This sequence continues until the end of the pregnancy. During the final few months of pregnancy, the tibiae and feet rotate medially (internally), while the hips and femora rotate laterally. This occurs because of the changing position of the baby in the uterus. Because of this, the hip joint becomes contracted in an external rotation position. As a result, the breech position has the highest incidence rate for malformation.

• Insufficient Amniotic Fluid: If the pregnant mother suffers from oligohydramnios, a condition in which the body does not produce enough amniotic fluid for the developing fetus, this might pose a concern.

• Sleeping Position of the Baby: This position of the foot is referred to as hyper plantar flexion. This led to the shortening and tightness of the calf muscles, which resulted in a walking stride or foot that abnormally pronated, imposing strain on the other major muscles of the lower leg.

What Are the Characteristic Features of Metatarsus Adductus?

• Active medial deviation of the foot occurs spontaneously in a child.

• Having a high arch.

• The first and second toes are further apart.

• Fixed adductus of the forefoot with the hindfoot in a neutral position.

• The sole of the foot is shaped like a bean.

What Is the Grading for the Condition?

Classification of Metatarsus Adductus by Bleck: In typical circumstances, the Bleck method depends on the heel bisector line, which should align with the web space between the second and third toes.

• Normal: The heel bisector line runs through the 2nd and 3rd toe webspace.

• Mild: The heel bisector line passes through 3rd toe.

• Moderate: The heel bisector passes through the 3rd and 4th toe webspace.

• Severe: The heel bisector passes through the 4th and 5th toe webspace.

What Are the Types of Metatarsus Adductus?

Metatarsus adductus can be classified as flexible or rigid:

• Flexible: In the tarsometatarsal joint, the fifth metatarsal bone has an adducted position. This condition has the flexibility of the foot.

• Rigid: This condition is present when there is a medial subluxation of the tarsometatarsal joints. As a result, the hind foot is turned inwards, known as the valgus, and the navicular bone is positioned posteriorly concerning the head of the talus.

How Is the Metatarsus Adductus Diagnosed?

The diagnosis of metatarsus adductus can be accomplished using various methods, including:

• Physical Examination: Throughout the physical examination, the patient's birth history, as well as their family history and clinical findings, are examined. During the clinical examination, the primary focus is placed on the medial deviation of the forefoot on the hindfoot. Secondary characteristics include a prominent base of the fifth metatarsal, a neutral or slightly valgus hindfoot, a slightly supinated forefoot, and a crease on the medial aspect of the foot. In addition, the distance between the first and second toes may increase. Another complication is associated with the patient's age at the time of diagnosis, and the patient will have an internal tibial torsion.

• Imaging Test: The non-flexible metatarsus adductus can be diagnosed with the help of X-rays, which utilize electromagnetic energy to make images of the internal tissue, bone, and organs of the body. Due to a persistent malformation, a standing or induced weight-bearing view may reveal a trapezoidal shape of the medial cuneiform and a medial deviation of the metatarsals.

How Can It Be Treated?

Metatarsus adductus is a frequent ailment that can be addressed regardless of the severity; nevertheless, rapid interventions for the child after birth have a better prognosis because they are performed on the child when the child is still young. While treating severe cases of metatarsus adductus, surgical intervention is typically recommended.

The position of the forefoot and heel will be corrected as part of the treatment, which has this as its primary objective. The treatment is individualized and varies depending on the patient's age and developmental stage.

• Observation: Observation is advised for those with a flexible or pliable forefoot. In the majority of cases, the metatarsus adductus resolves without therapy. Individuals are told to conduct passive manipulation exercises on their feet, and a change in sleeping position may also aid in correcting the position of the forefoot and heel. Without the development of hindfoot valgus, footprint and radiographic improvement were found with both approaches.

• Stretching: Stretching is a form of physical exercise that involves putting a certain body component into a specific position. This helps lengthen and elongate the muscle or muscle group and improves flexibility and elasticity. If the metatarsus adductus is flexible and actively corrects itself when the foot is stimulated, then the problem will correct itself independently. The little defects will disappear once some time has passed.

• Casting: As the foot has not adjusted towards the stretching treatment, casting is the next recommended course of action. As a result of the cast's assistance, the soft tissue of the forefoot was successfully stretched. Following a predetermined amount of time, the plaster cast was modified. When the patient's foot reacts to the casting, a pair of straight last shoes, constructed without a curve in the sole of the shoe, is recommended to assist in keeping the foot in its correct position.

• Surgery: Surgical therapy is rarely necessary, but when it is, it could involve releasing the abductor hallus, performing a medial capsulotomy, or performing osteotomies. The surgical procedure in question does not produce reliable results. In the extremely rare circumstance of an older kid with a persistent disabling deformity, it may even comprise an opening wedge osteotomy of the medial cuneiform, with or without a closing wedge osteotomy of the cuboid, or osteotomies of the bases of metatarsals. Following the procedure, the forefoot will have a cast attached to it to recover properly.

The following are two other surgical treatments that have been suggested for the treatment of metatarsus adductus:

1. Anteromedial decompression was performed with capsulotomy of the medial metatarso-cuneiform and naviculo-cuneiform joints.

2. A capsulotomy of the naviculo-cuneiform joint was performed, along with the posterior tibial tendon transfer.

Which All Factors Determine the Treatment Plan?

• Factors of a physical nature, including but not limited to age, general health, and medical history.

• The severity of the ailment.

• The capacity for dealing with particular medications, methods, or treatments.

• The hypothesized reason for the occurrence of the condition.

What Are the Complications of the Metatarsus Adductus?

In neonates, the presence of a metatarsus adductus would be associated with an increased risk of developmental deformity of the hip. Developmental dysplasia of the hip, also known as DDH, is a disorder of the hip joint that causes the femur at the top of the thigh to slip in and out of its socket. This happens because the socket is insufficiently deep to maintain the joint's integrity. A disparity in leg length and the appearance of a limp may result from DDH. If the MA is severe, it may cause bunions, hammertoes, and other foot disorders.

Conclusion

A postural deformity known as metatarsus adductus occurs when a young child is born with an inward deviation of the forefoot compared to the hindfoot. This occurs at birth. The deformity can be quite minor and go away on its own, it is also possible to be slightly fixed and continue into the walking age, or it is also likely inflexible and connected with the valgus of the hindfoot. The clinical and imaging evaluations would help more accurately assess the real deformity. Assessing the many different approaches to surgical procedures could contribute to an improvement in patient outcomes. The treatment modalities help provide a better prognosis for the problem, and it is normal for the condition to self-correct over the years. Nonetheless, the patient should be observed throughout the year to document the advancement of the illness.