Dysplasia Epiphysealis Hemimelica 

Updated: Jun 07, 2018
Author: David A Forsh, MD; Chief Editor: Harris Gellman, MD 

Overview

Background

Dysplasia epiphysealis hemimelica (DEH), or Trevor disease, is a rare developmental disorder affecting the epiphyses in young children.[1, 2, 3] It is commonly thought of as a variant of osteochondroma arising from an epiphysis.[4, 5, 6]

The first report of DEH in the literature was by Mouchet and Belot in 1926, who described the condition as a tarsal bone disorder and used the French term tarsomegalie.[7] In 1950, Trevor reviewed 10 cases of DEH and used the term tarsoepiphyseal aclasis.[8] In 1956, Fairbank reported 14 cases and coined the term dysplasia epiphysealis hemimelica.[9, 10, 11, 12, 13, 14, 15, 16, 17, 18]

The typical DEH patient presents during childhood or adolescence. The characteristic lesions are intra-articular, are hemimelic (involving only half of the joint), have a predilection for the lower extremity, and may be single or multiple.[2]  The differential diagnoses include chondroblastoma, osteochondroma, and enchondroma.[11, 4, 5, 19] Most cases are treated surgically.

Pathophysiology and Etiology

Many theories exist regarding the pathophysiology of DEH. Connor et al suggested that the fundamental defect was an abnormality of the regulation of cartilage proliferation in the affected epiphysis, resulting in cartilaginous exostosis.[20]

Trevor considered DEH to be a congenital error in epiphyseal development that affects the limb buds during early fetal life; it was thought to involve an altered process of cell proliferation at the superficial zone of articular cartilage, allowing for persistent proliferation and production of a large cartilaginous mass.[8]

Fairbank suggested that the disorder derived from a localized disturbance of the preaxial or postaxial apical cap of the limb bud in early fetal development.[9, 11]

The etiology of DEH is unknown; the disease does not appear to be genetically transmitted.

Epidemiology

The incidence of DEH has been estimated to be 1 case per million population. It is a rare disorder both in the United States and internationally. Although DEH may occur at any age, it usually manifests in childhood and early adolescence. DEH is more commonly found in males, with a male-to-female ratio of 3:1. No racial predilection is known to exist.

Prognosis

DEH is a benign disorder, and no cases of malignant transformation have been reported. Its natural history is that of a lesion that continuously increases in size until skeletal maturity; therefore, the long-term prognosis for untreated lesions involving the weightbearing surface of the joint, though unreported, is one of a progression toward pain and arthrosis.

DEH, though an uncommon condition, can result in considerable disability as consequence of the direct involvement of the articular surface of the joint. Treatment with surgical excision offers the best results, but corrective osteotomy and reoperation for recurrent lesion may also be required.[21, 22]

 

Presentation

History and Physical Examination

Dysplasia epiphysealis hemimelica (DEH), or Trevor disease, most commonly occurs around the knee, talus, and the tarsal navicular and first cuneiform joints. Common manifestations include the following[23, 24] :

  • Osseous lesion at the epiphysis of a bone in the lower extremity (though upper extermities may be involved as well) that slowly increases in size until skeletal maturity
  • Pain
  • Swelling
  • Stiffness
  • Restriction of range of motion (ROM)

Most patients present with painless swelling or a mass on one side of a joint, limitation of motion, angular deformity, concomitant regional muscle wasting, and, occasionally, recurrent locking of the joint. Typically, only one half of the epiphysis is involved; however, involvement of the entire epiphysis has been described.[9, 20, 25] The medial side of the epiphysis is most commonly affected.[10, 26, 27, 28]

The most common presenting symptom is the presence of a mass with the consistency of bone. Deformity, aching pains, and limited ROM may accompany the mass presentation.[9, 10, 29, 30] Lengthening or shortening of the affected limb, regional muscle atrophy, genu valgum, genu varum, or equinus of the ankle may also be present; multiple-site involvement in a single limb is reported in the majority of cases.[29, 31, 25, 32]  On physical examination, involved joints commonly exhibit decreased ROM, joint stiffness, and tenderness to palpation.

Classification

Azouz et al classified DEH into the following clinical types[33] :

  • Localized DEH, which involves only one epiphysis
  • Classic DEH (most common), which affects more than one area in a single limb
  • Generalized DEH, which affects the whole lower limb, from the pelvis to the foot
 

DDx

 

Workup

Imaging Studies

Dysplasia epiphysealis hemimelica (DEH), or Trevor disease, typically is well demonstrated on plain radiography; however, computed tomography (CT) or magnetic resonance imaging (MRI) may provide additional anatomic detail.[30]

Plain radiography may reveal early focal calcification of the affected site, with later appearance of an irregular bony enlargement that becomes fused to the affected epiphysis.[34] (See the images below.)

Lateral view of left foot. Medial ankle and subtal Lateral view of left foot. Medial ankle and subtalar joints are significantly involved with epiphyseal growth irregularities.
Anteroposterior view of left foot. Medial ankle an Anteroposterior view of left foot. Medial ankle and subtalar joints are significantly involved with epiphyseal growth irregularities.
Oblique view of left foot. Medial ankle and subtal Oblique view of left foot. Medial ankle and subtalar joints are significantly involved with epiphyseal growth irregularities.
Anteroposterior view of left ankle of 12-year-old Anteroposterior view of left ankle of 12-year-old boy. Medial ankle and subtalar joints and first metatarsophalangeal joints have large epiphyseal osteocartilaginous growths causing significant anatomic changes and clinical symptoms. Large lesion at first metatarsophalangeal joint required excision.
Anteroposterior view of left ankle of 12-year-old Anteroposterior view of left ankle of 12-year-old boy. Medial ankle and subtalar joints and first metatarsophalangeal joints have large epiphyseal osteocartilaginous growths causing significant anatomic changes and clinical symptoms. Large lesion at first metatarsophalangeal joint required excision.
Three-dimensional reconstruction images of left fo Three-dimensional reconstruction images of left foot (seen in radiographs of 12-year-old boy's foot) better demonstrate numerous epiphyseal abnormalities, especially at lateral tibial-talar and first metatarsal-phalangeal joints. Entire subtalar joint is also involved. Smaller irregularities are seen in nearly all epiphyses of foot.
Three-dimensional reconstruction images of left fo Three-dimensional reconstruction images of left foot (seen in radiographs of 12-year-old boy's foot) better demonstrate numerous epiphyseal abnormalities, especially at lateral tibial-talar and first metatarsal-phalangeal joints. Entire subtalar joint is also involved. Smaller irregularities are seen in nearly all epiphyses of foot.

CT can assist in defining the anatomic relation between the mass and its parent bone, and it is also useful for evaluating the condition of the articular cartilage and soft tissue.[35]

MRI depicts the unossified cartilaginous mass in great detail, as well as the status of the articular cartilage, and it helps differentiate abnormal epiphyseal growth from the main epiphysis.[13, 15, 30, 34, 36]

Double-contrast arthrography can assist in delineating joint space deformity, the extent of a cartilaginous mass, and the joint dynamic, but it is an invasive diagnostic tool.

Histologic Findings

Macroscopically, the bone enlargement caused by DEH is consistent with an exostosis and normal hyaline cartilage.

Microscopically, the histologic appearance of the lesion is that of a well-defined cartilage cap over projecting bone that is contiguous with the underlying normal bone and strongly resembles that of a benign osteochondroma. Whereas a typical osteochondroma arises from the metaphysis or diaphysis, DEH arises from the epiphysis.[2]  A histologic comparative study by Stevens et al found both morphologic and immunohistologic differences between DEH and osteochondromas in histologic sections.[37]

The basic pathologic process in DEH appears to be abnormal cartilage proliferation in an epiphysis with associated enchondral ossification before complete ossification. A cleavage area of cartilage is present between the ossification center in the lesion and that of the epiphysis.[4]

 

Treatment

Approach Considerations

Dysplasia epiphysealis hemimelica (DEH), or Trevor disease, should be treated if the lesion is causing deformity, pain, or interference with function.

Supportive joint care, consisting of short-term splinting of the joint, may be beneficial in management. Most cases are treated surgically, but recurrence is common.[29, 38, 39] The most common procedures are excision of the mass and corrective osteotomy.[30]  Excision may be arthroscopic or open. Corrective osteotomy and, subsequently, hemiepiphysiodesis have been described for correction of deformity.[30, 23]  Surgery is contraindicated if no medical symptoms or no mechanical block is present.

Surgical Therapy

Most reported cases of DEH in the literature have been treated surgically. Surgical treatment has involved excising the mass and correcting any angular deformity while preserving the integrity of the affected joint to the extent possible.[40, 41]

Oberc et al reported on their experience in treating DEH in six children.[42] Of the four patients treated surgically, two experienced late complications. Of the two patients treated conservatively, one had a positive outcome and the other a negative outcome involving hip ankylosis. The authors advised that conservative treatment involving physical therapy be employed initially in the region of pain and that surgical treatment be considered if pain, joint deformation, or limited range of motion (ROM) persists.

Complications

Recurrence of the angular deformity after the corrective osteotomy may be anticipated if the growth plate at the affected joint is open and active and the lesion itself has not been removed.[30, 31]

Other potential complications include the following:

Long-Term Monitoring

After surgery, a short period of immobilization with a cast or splint is required for the affected limb, followed by active ROM of the joint.

Bosch et al conducted a retrospective study of nine patients with DEH who were treated surgically and were followed up clinically with imaging.[44] Magnetic resonance imaging (MRI) was found to be useful for identifying a potential plane of cleavage between the epiphysis and the pathologic tissue. The investigators recommended early removal of ossifications when a cleavage plane is identified and advised against waiting for a possible complication or for an increase in size.

Because of the risk of recurrence, patients should be followed until skeletal maturity.[24]