Introduction:
Dysplasia epiphysealis hemimelica (DEH), also known as Trevor's disease, is a rare developmental disorder that primarily affects the epiphyseal growth plates of bones. First described by Mouchet and Belot in 1926 and later named after Dr. M. A. Trevor, who extensively studied the condition in the 1950s, DEH is characterized by the abnormal growth of cartilage within the epiphyses, leading to deformities and functional limitations.
What Is Dysplasia Epiphysealis Hemimelica?
Dysplasia epiphysealis hemimelica (DEH) is an extremely rare condition, with fewer than 100 cases reported in the medical literature. It predominantly affects children and adolescents, with a slight male predilection. The exact cause of DEH remains unclear, but some researchers speculate that it may be related to genetic mutations or disturbances during embryonic development.
The condition typically manifests as asymmetric overgrowth of cartilage within the epiphyses of long bones, most commonly in the ankle and knee joints. However, DEH can also affect other joints, including the wrist, hip, and shoulder. The overgrowth is often painless but can lead to progressive deformities and functional limitations as it interferes with joint mobility.
What Is the Pathogenesis of Dysplasia Epiphysealis Hemimelica?
The exact cause of dysplasia epiphysealis hemimelica (DEH) remains unclear. However, it is believed to be a congenital disorder that arises from abnormalities in the growth plate cartilage during embryonic development. Genetic factors may also play a role, as DEH has been reported in some families.
What Are the Clinical Features of Dysplasia Epiphysealis Hemimelica?
Dysplasia epiphysealis hemimelica (DEH) primarily affects the epiphyseal growth plates of the long bones, most commonly in the lower extremities. The knee joint is the most common site of involvement, followed by the ankle, wrist, and hip joints. DEH typically presents unilaterally, affecting only one side of the body, and can vary in severity from mild to severe.
The clinical presentation of DEH can vary widely depending on the location and extent of the affected joint. Common features include:
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Asymmetric Growth: The hallmark of DEH is the uneven or asymmetric growth of one side of a joint. This can result in limb length discrepancies and joint deformities.
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Painless Swelling: Swelling or enlargement of the affected joint is often one of the earliest signs. Unlike many other joint conditions, DEH is typically painless in its early stages.
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Limited Range of Motion: As the cartilaginous overgrowth progresses, it can restrict joint movement. This limitation can be particularly pronounced in weight-bearing joints like the ankle or knee.
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Joint Instability: In some cases, DEH can lead to joint instability due to the disruption of normal joint anatomy. This can result in frequent dislocations or subluxations.
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Compression of Adjacent Structures: In severe cases, the cartilaginous masses can compress nearby nerves, blood vessels, or other structures, leading to neurological or vascular symptoms.
What Is the Diagnosis of Dysplasia Epiphysealis Hemimelica?
Diagnosing dysplasia epiphysealis hemimelica (DEH) can be challenging due to its rarity and the need for specialized imaging. In addition to radiography, MRI (magnetic resonance imaging) and CT (computed tomography) scans may be necessary to evaluate the extent of the lesion and its effects on surrounding tissues.
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Clinical Evaluation: A thorough clinical evaluation, including a detailed medical history and physical examination, is the initial step in diagnosing DEH. The asymmetrical overgrowth and joint abnormalities are key clinical clues.
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Imaging: Radiological studies, such as X-rays and MRI (magnetic resonance imaging) scans, play a crucial role in confirming the diagnosis. X-rays can reveal the characteristic irregularities in the epiphysis, while MRI can provide more detailed information about the extent of involvement.
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Biopsy: In some cases, a biopsy may be necessary to confirm the diagnosis. A histopathological examination of the affected tissue can reveal the presence of abnormal cartilage growth within the epiphysis.
Radiographic Findings:
Radiographic imaging is essential for diagnosing DEH. X-rays reveal the characteristic features of this condition, which include:
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Overgrowth of the Epiphysis: Affected epiphyses show irregular and excessive growth, often resembling cauliflower-like masses.
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Epiphyseal Involvement: DEH typically affects only one side of a joint, which distinguishes it from other conditions like multiple osteochondromatosis.
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Joint Space Preservation: Unlike conditions like osteoarthritis, the joint space is usually preserved in DEH.
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Bone Deformities: Over time, DEH can lead to bone deformities, such as angular deformities and limb length discrepancies.
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Soft Tissue Involvement: In some cases, DEH can involve the adjacent soft tissues, such as ligaments and tendons, which may contribute to joint instability.
What Is the Treatment of Dysplasia Epiphysealis Hemimelica?
The management of dysplasia epiphysealis hemimelica is primarily aimed at improving the patient's quality of life by addressing the associated deformities and functional limitations. Treatment options may include:
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Observation: In some cases, particularly when the condition is mild and does not significantly impact the patient's daily life, a watch and wait approach may be recommended. Regular follow-up appointments are essential to monitor disease progression.
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Surgical Intervention: Surgery is often necessary when DEH causes significant deformities, impairs joint function, or results in neurological or vascular compression. Surgical options may include:
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Excision of the Cartilaginous Mass: The removal of abnormal cartilage growth is the most common surgical procedure. This can be done using various techniques, including arthroscopy or open surgery.
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Joint Stabilization: In cases of joint instability, surgical procedures may be performed to restore normal joint anatomy and stability.
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Limb-Length Equalization: If DEH leads to substantial limb length discrepancies, surgical procedures may be employed to equalize the lengths of the affected and unaffected limbs.
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Physical Therapy: Post-surgery, physical therapy is often recommended to improve joint function, range of motion, and strength. Physical therapists can design individualized rehabilitation programs to meet the patient's specific needs.
What Is the Prognosis of Dysplasia Epiphysealis Hemimelica?
The prognosis for individuals with dysplasia epiphysealis hemimelica varies depending on various factors, such as the extent of the lesion, the age of onset, and the effectiveness of treatment. Early diagnosis and appropriate treatment plans can lead to better outcomes. In mild cases managed conservatively, the prognosis is generally favorable, with many patients experiencing resolution of symptoms as they grow.
In more severe cases or when left untreated, DEH can lead to significant joint deformity and functional limitations. Therefore, timely intervention is crucial to minimize the long-term impact of the condition.
Conclusion
Dysplasia epiphysealis hemimelica, though rare, is a significant orthopedic challenge that primarily affects children and adolescents. Its variable clinical presentation and overlap with other orthopedic conditions make accurate diagnosis crucial. With advancements in diagnostic imaging and treatment modalities, healthcare professionals can better manage DEH and improve the quality of life for affected individuals. Research related to the genetic and molecular mechanisms underlying DEH is ongoing, which may lead to more targeted therapies in the future. Until then, a multidisciplinary approach involving orthopedic surgeons, radiologists, and physical therapists remains essential in providing optimal care for individuals with this rare orthopedic disorder.
