Exploring Tarsal Coalition: From Diagnosis to Treatment

Tarsal coalition is a condition that affects the tarsal bones in the foot, causing an abnormal connection between two or more bones. This fusion can lead to pain, stiffness, and limited mobility, impacting a person’s daily activities and quality of life. Understanding this condition is crucial for both patients and healthcare providers to ensure proper diagnosis and treatment.

The journey from diagnosis to treatment of tarsal coalition involves several key aspects. These include recognizing the symptoms, utilizing appropriate imaging techniques, and exploring various management options. By delving into these areas, individuals can gain valuable insights into this complex foot condition and the available approaches to address it effectively.

Table of Contents

Understanding Tarsal Coalition

Tarsal coalition is an abnormal connection between two or more tarsal bones in the foot. This connection can be fibrous (syndesmosis), cartilaginous (synchondrosis), or bony (synostosis). The most common sites of tarsal coalition are between the calcaneus and navicular bones (calcaneonavicular coalition) or between the talus and calcaneus bones (talocalcaneal coalition).

The prevalence of tarsal coalition is estimated to be 1-2% in the general population, although cadaveric studies have reported a prevalence of up to 13%. Talocalcaneal coalition accounts for approximately 45% of all tarsal coalitions. The condition is often present at birth but typically becomes symptomatic in early adolescence, around ages 12 to 15, when the coalition ossifies.

Tarsal coalition is caused by a failure of mesenchymal segmentation and differentiation during fetal development. This failure results in an incomplete separation of the tarsal bones, leading to the formation of a fibrous, cartilaginous, or bony bridge between them. An autosomal dominant inheritance pattern with variable penetrance has been proposed as a potential cause of congenital tarsal coalition.

In addition to congenital causes, acquired tarsal coalition can occur due to trauma, degeneration, inflammatory arthritis, neoplasia, or infections of the hindfoot or midfoot. Tarsal coalition has also been associated with certain syndromes, such as Apert syndrome, Nievergelt-Pearlman syndrome, and clubfoot deformities.

The presence of a tarsal coalition can lead to a loss of normal subtalar joint motion, resulting in increased stress on neighboring joints, particularly the ankle and talonavicular joints. This altered biomechanics can cause laxity in the ankle joint, beaking at the talar neck, and the development of rigid flatfoot deformity with peroneal spasm.

Symptoms and Clinical Presentation

The symptoms of tarsal coalition often remain unnoticed until late childhood or early adolescence. Many individuals with this condition may not experience any noticeable symptoms or foot deformity. However, when symptoms do occur, they can have a significant impact on daily activities and quality of life.

Common signs and symptoms of tarsal coalition include:

Stiff and painful feet, particularly below the ankle and around the middle or back half of the foot
Rigid, flat feet that make walking on uneven surfaces challenging
Increased pain or a limp during higher levels of activity
Recurrent ankle sprains due to excessive rolling of the ankle to compensate for the foot’s lack of motion

The age of onset for tarsal coalition symptoms typically ranges from 8 to 16 years old, depending on the specific bones involved. As a child grows and the cartilage in their feet ossifies into mature bone, the coalition may harden and fuse the affected tarsal bones together. This process leads to hindfoot stiffness, causing pain and other associated symptoms.

Tarsal coalition can have a profound impact on an individual’s daily activities. The pain and stiffness in the feet can make walking, running, and participating in sports or other physical activities difficult. The rigid, flat feet associated with this condition may also cause discomfort when wearing certain types of shoes or walking on uneven surfaces. These limitations can affect a person’s overall mobility and quality of life, making early diagnosis and appropriate treatment crucial for managing the symptoms effectively.

Diagnosis and Imaging

Diagnosis of tarsal coalition involves a combination of physical examination and imaging techniques. Physical examination may reveal a rigid, flat foot with limited range of motion in the subtalar joint. The patient may experience pain or discomfort during the examination, particularly when the affected area is palpated or manipulated.

Physical Examination

During the physical examination, the healthcare provider will assess the patient’s gait, foot posture, and range of motion. They may also check for tenderness or swelling in the affected area. A thorough physical examination can provide valuable insights into the presence and severity of tarsal coalition.

X-rays and CT Scans

Radiographic imaging is a crucial tool in diagnosing tarsal coalition. Standard radiographic views, including anteroposterior (AP), lateral, and oblique projections of the foot, can help identify bony coalitions. Calcaneonavicular coalitions are best visualized on a 45° internal oblique view, while talocalcaneal coalitions may require additional views, such as the Harris-Beath (axial) view of the hindfoot.

Computed tomography (CT) scans provide more detailed images of the tarsal bones and can help determine the extent of the coalition. CT scans are particularly useful for preoperative planning and assessing the involvement of articular surfaces. Coronal and axial views with a section thickness of 3 mm or less are optimal for evaluating tarsal coalitions.

MRI and Other Imaging Techniques

Magnetic resonance imaging (MRI) is another valuable tool in diagnosing tarsal coalition, especially for detecting non-osseous coalitions, such as fibrous or cartilaginous types. MRI can provide detailed images of the soft tissues, bone marrow, and articular surfaces. Fat-suppressed sequences, such as short-tau inversion recovery (STIR) or fat-suppressed T2-weighted sequences, are particularly useful for evaluating bone marrow edema and inflammatory changes associated with tarsal coalition.

Other imaging techniques, such as bone scintigraphy, may be used as a screening tool when plain radiographs are equivocal. Scintigraphy can demonstrate increased uptake at the site of the coalition, helping to localize the affected area.

In summary, the diagnosis of tarsal coalition requires a comprehensive approach that includes physical examination and various imaging modalities. Radiographs, CT scans, and MRI are the primary tools used to confirm the diagnosis and guide treatment decisions. By utilizing these diagnostic techniques, healthcare providers can accurately identify the presence and extent of tarsal coalition, enabling them to develop an appropriate management plan for each patient.

Treatment Options and Management

The treatment of tarsal coalition aims to alleviate pain, improve foot function, and prevent the progression of deformity. The choice between conservative and surgical management depends on the severity of symptoms, the extent of the coalition, and the presence of secondary changes in the foot.

Conservative treatments are often the first line of management for symptomatic tarsal coalitions. These may include:

Immobilization with a cast or boot to reduce pain and inflammation
Orthotic devices to support the foot and control abnormal motion
Physical therapy to improve flexibility and strength
Anti-inflammatory medications to manage pain and swelling

If conservative measures fail to provide adequate relief or if the coalition is causing significant deformity, surgical intervention may be necessary. The two primary surgical options are:

Resection of the coalition: This involves removing the abnormal connection between the tarsal bones and interposing fat, muscle, or bone wax to prevent recurrence. Resection is typically recommended for smaller, symptomatic coalitions in younger patients with minimal secondary changes.
Arthrodesis (fusion) of the affected joints: This procedure is indicated for larger coalitions, those associated with significant deformity, or when degenerative changes are present in the surrounding joints. Arthrodesis provides stability and pain relief but sacrifices joint motion.

Post-treatment care and recovery are crucial for optimal outcomes. After conservative treatment, patients may need to gradually return to activities while continuing to use orthotics or supportive devices. Following surgical resection, immobilization in a cast or boot is necessary for 4-6 weeks, followed by physical therapy to regain strength and mobility. Arthrodesis requires a longer period of immobilization and rehabilitation, typically 8-12 weeks, to allow for proper healing of the fused joints.

Long-term follow-up is essential to monitor for recurrence of symptoms, the development of secondary changes, and to ensure the best possible functional outcome for patients with tarsal coalition.

Conclusion

Tarsal coalition has a significant impact on foot function and mobility, affecting individuals from childhood through adulthood. Understanding its causes, symptoms, and diagnostic methods is crucial to provide effective care. From conservative approaches like orthotics and physical therapy to surgical interventions such as resection or fusion, treatment options aim to alleviate pain and improve quality of life. The choice of treatment depends on the severity of symptoms and the extent of the coalition.

Managing tarsal coalition requires a comprehensive approach, involving healthcare professionals, patients, and their families. Early diagnosis and appropriate treatment can help prevent long-term complications and maintain foot function. As research in this field continues, new techniques and therapies may emerge, offering hope for better outcomes and enhanced management strategies to address this complex foot condition.

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