Orthopedics

Radiologic Case Study 

Dysplasia Epiphysealis Hemimelica (Trevor Disease) of the Ankle

Philip D. Nowicki, MD, FAAP; Heather Borders, MD

Abstract

An 11-year-old boy presented with a 2-year history of left ankle pain and abnormal gait, worsened with sports activities such as football and wrestling.

Figure:

Standing anteroposterior radiograph of the left ankle (A) with lateral radiograph of the left foot (B).

Abstract

An 11-year-old boy presented with a 2-year history of left ankle pain and abnormal gait, worsened with sports activities such as football and wrestling.

Figure:

Standing anteroposterior radiograph of the left ankle (A) with lateral radiograph of the left foot (B).

Answer to Radiologic Case Study

Dysplasia Epiphysealis Hemimelica (Trevor Disease) of the Ankle

An 11-year-old boy presented with a 2-year history of aching-type left ankle pain. The pain was not present at night but occurred with activities, especially recreational football and wrestling. Physical examination denoted absence of an antalgic-type gait, but he walked with his left foot externally rotated. There was tenderness along the medial left ankle joint and talus without appreciable edema in the ankle joint region and no mechanical joint findings on dynamic examination. There were no signs of planovalgus foot with standing.

Anteroposterior (AP) and lateral radiographs of the ankle and foot demonstrated a partially ossified, lobulated intra-articular mass within the medial gutter of the ankle joint ( Figure 1 ). Computed tomography (CT) and magnetic resonance imaging (MRI) of the ankle were obtained to further define the lesion along with its position in relation to surrounding structures. Computed tomography denoted an irregularly shaped, protuberant bony lesion connected to the anteromedial talus and a contiguous component of partially calcified soft tissue that demonstrated a cleavage plane with the talus ( Figure 2 ). Magnetic resonance imaging demonstrated protuberant bone and soft tissue adjacent to the medial talus. The signal in the anterior component was mostly isointense to bone, whereas the signal in the posterior component was partially isointense to cartilage, with areas of low signal corresponding to the areas of calcification ( Figure 3A ). A thin cartilage cap was also present, isointense to articular cartilage ( Figure 3B ). There was mild edema in the bone and soft tissues, and also within the deep deltoid ligament fibers. Displacement of the posterior tibialis and flexor digitorum tendons was present, and there was irregularity of the medial talar dome and overlying articular cartilage suggesting chondromalacia and osteochondral injury. No synovitis was appreciated within the ankle joint.

Anteroposterior radiograph of the left ankle demonstrating a lobulated, irregularly shaped intra-articular bone mass (white arrow) in the medial joint space with subchondral changes of the medial talar dome (A). Lateral radiograph of the left ankle and foot exhibiting no extension of the bone lesion anteriorly or posteriorly in the ankle joint or foot (B).

Figure 1:

Anteroposterior radiograph of the left ankle demonstrating a lobulated, irregularly shaped intra-articular bone mass (white arrow) in the medial joint space with subchondral changes of the medial talar dome (A). Lateral radiograph of the left ankle and foot exhibiting no extension of the bone lesion anteriorly or posteriorly in the ankle joint or foot (B).

Coronal computed tomography scan of the ankle demonstrating irregularly shaped protuberant bone (white arrow) in the medial aspect of the joint (A). Axial computed tomography scan of the ankle demonstrating an irregularly shaped protuberant bone lesion of the medial ankle joint, with a portion connected to the anterior talus, and a second lesion more posteriorly located, with a defined cleft (black arrows) at the interface (B).

Figure 2:

Coronal computed tomography scan of the ankle demonstrating irregularly shaped protuberant bone (white arrow) in the medial aspect of the joint (A). Axial computed tomography scan of the ankle demonstrating an irregularly shaped protuberant bone lesion of the medial ankle joint, with a portion connected to the anterior talus, and a second lesion more posteriorly located, with a defined cleft (black arrows) at the interface (B).

Coronal T1-weighted magnetic resonance image of the ankle demonstrating an internal signal (white arrow) isointense to bone marrow/fat and low signal areas corresponding to calcification (A). Axial T1-weighted fat-suppressed magnetic resonance image of the ankle after intravenous contrast administration showing the thin cartilage cap of the lesion (white arrow), as demonstrated by an isointense signal similar to articular cartilage. There is also displacement of the tibialis posterior and flexor digitorum tendons (asterisks) with irregularity of the medial talar dome (black arrowhead) and overlying articular cartilage suggesting chondromalacia and osteochondral injury (B).

Figure 3:

Coronal T1-weighted magnetic resonance image of the ankle demonstrating an internal signal (white arrow) isointense to bone marrow/fat and low signal areas corresponding to calcification (A). Axial T1-weighted fat-suppressed magnetic resonance image of the ankle after intravenous contrast administration showing the thin cartilage cap of the lesion (white arrow), as demonstrated by an isointense signal similar to articular cartilage. There is also displacement of the tibialis posterior and flexor digitorum tendons (asterisks) with irregularity of the medial talar dome (black arrowhead) and overlying articular cartilage suggesting chondromalacia and osteochondral injury (B).

The patient was taken to the operating room, where the lesion was exposed through a medial malleolar osteotomy distal to the physeal plate ( Figure 4A ). Two large osteocartilaginous lesions were removed from the talus and ankle joint ( Figure 4B ). Of note was the presence of a small osteochondritis lesion (5×5 mm) of the talar dome that was subsequently curetted to stable cartilage and microfractured with a drill bit. Pathology specimen was read as osteochondroma. Immediate ( Figure 5A ) and 16-month postoperative ( Figure 5B ) AP views of the ankle after smooth pin removal are shown. The patient was pain free with all chosen activities at final follow-up.

Intraoperative photograph of the ankle joint with exposure of the talar lesion medially through a medial malleolus osteotomy approach. The malleolar fragment is retracted with a bone hook toward the left side of the image. The patient’s head is toward the top of the picture and the foot toward the bottom. A Freer elevator points to the lesion in situ at the medial talus (A). Gross pathological specimen photograph denoting the size and shape of the excised talar lesion. Grossly, the lesion is a mix of bone and cartilage that is consistent with a diagnosis of osteochondroma (B).

Figure 4:

Intraoperative photograph of the ankle joint with exposure of the talar lesion medially through a medial malleolus osteotomy approach. The malleolar fragment is retracted with a bone hook toward the left side of the image. The patient’s head is toward the top of the picture and the foot toward the bottom. A Freer elevator points to the lesion in situ at the medial talus (A). Gross pathological specimen photograph denoting the size and shape of the excised talar lesion. Grossly, the lesion is a mix of bone and cartilage that is consistent with a diagnosis of osteochondroma (B).

Postoperative anteroposterior radiograph of the ankle showing full excision of the previous talar lesion and healing of the medial osteotomy with smooth pin fixation (A). Sixteen-month postoperative anteroposterior radiograph of the ankle after pin removal demonstrating no signs of talar lesion recurrence, still with subchondral irregularity of the medial talar dome (white arrow) but stable. Of note, there is no sign of physeal arrest after previous smooth pin fixation for medial malleolus osteotomy, which is fully healed (B).

Figure 5:

Postoperative anteroposterior radiograph of the ankle showing full excision of the previous talar lesion and healing of the medial osteotomy with smooth pin fixation (A). Sixteen-month postoperative anteroposterior radiograph of the ankle after pin removal demonstrating no signs of talar lesion recurrence, still with subchondral irregularity of the medial talar dome (white arrow) but stable. Of note, there is no sign of physeal arrest after previous smooth pin fixation for medial malleolus osteotomy, which is fully healed (B).

Discussion

Dysplasia epiphysealis hemimelica (DEH), also known as Trevor disease, is a rare disorder of unknown etiology with an estimated incidence of 1:1,000,000. 1–4 There is a male:female ratio of 3:1. 2–5 Most cases occur in the first decade of life. 2 The ankle joint is most often affected, followed by the knee, with 54% of cases affecting the ankle joint. 1,3 Fair-bank originally described the condition as cartilaginous overgrowth of a long bone epiphysis that occurs on one side of an affected limb, usually medial. 1 Dysplasia epiphysealis hemimelica was later classified by Azouz as having 3 distinct presentations: localized (1 epiphysis involved), classic (more than 1 epiphysis involved in the same extremity), and generalized (the entire limb affected). 1,6 Patients most commonly present with a painless limp and a localized mass that may increase in size, with or without adjacent joint deformity and stiffness. 3

Radiographs usually demonstrate a partially ossified, lobulated, cartilaginous mass arising unilaterally from the affected epiphysis with or without an osseous connection. 1,3–6 The diagnosis is usually made with radiographs, but the lesion can be mistaken for an intra-articular loose body, osteochondromatosis, or synovial chondromatosis. 4,6 Computed tomography and MRI can confirm the diagnosis, aid surgical planning, and define the relationship of the mass to local structures. 1,3,4 Specifically, CT can help define the anatomic relationship between the mass and the host bone, and MRI can show the extent of epiphyseal involvement and joint deformity and the status of the articular surface. 3,4 There may be a cleavage plane demonstrated between the lesion and host bone that gradually ossifies as the lesion matures. The lesion in this case had a portion confluent with the medial talus, whereas another portion had a cleavage plane with the adjacent talus.

Treatment for DEH depends on the status of the affected joint. Conservative management can be successful in early lesions, but surgical excision is recommended if progressive size, joint deformity, or pain occur. 1,3,4,6,7 Complete resection of all pathologic tissue is essential because any remaining tumor will continue to grow. 1 When present in the ankle, DEH is best treated aggressively with surgical excision at a time when surgical treatment will be easier and young joint cartilage less damaged, with best results occurring when joint deformity and persistent synovitis are not present. 1,5 Hemi-articular joint involvement, a hallmark finding in DEH, especially in a growing child, may lead to joint malalignment, specifically angular deformity, which may cause progressive symptomatology. Mild growth disturbance and osteochondral injury of the medial talus was demonstrated in the current patient with pain, suggesting a need for treatment. Bakerman et al 7 suggested yearly MRI follow-up after excision to monitor for recurrence.

The etiology of DEH is currently unknown, although it has been hypothesized that it is due to a defect in the regulation of cartilage proliferation. 7 The underlying pathology of DEH resembles an osteochondroma. Lesions are benign with normal cancellous bone and varying degrees of endochondral ossification and a hyaline cartilage cap. 1,2,4,6 No malignant degeneration has been reported to date. 1

Conclusion

Dysplasia epiphysealis hemimelica is a rare disorder that, although benign in nature, can be locally aggressive, especially when affecting the ankle joint. Aggressive surgical treatment with complete lesion resection is recommended before irreversible joint damage or deformity occurs.

References

  1. Struijs PAA, Kerkhoffs GMMJ, Besselaar PP . Treatment of dysplasia epiphysealis hemimelica: a systematic review of published reports and a report of seven patients . J Foot Ankle Surg . 2012 ; 51 : 620 – 626 . doi:10.1053/j.jfas.2012.05.008 [CrossRef]
  2. Merzoug V, Wicard P, Dubousset J, Kalifa G . Bilateral dysplasia epiphysealis hemimelica: report of two cases . Pediatr Radiol . 2002 ; 32 : 431 – 434 . doi:10.1007/s00247-001-0626-y [CrossRef]
  3. Kuo RS, Bellemore MC, Monsell FP, Frawley K, Kozlowski K . Dysplasia epiphysealis hemimelica: clinical features and management . J Pediatr Orthop . 1998 ; 18 : 543 – 548 . doi:10.1097/01241398-199807000-00028 [CrossRef]
  4. Gokkus K, Aydin AT, Uyan A, Cengiz M . Dysplasia epiphysealis hemimelica of the ankle joint: a case report . J Orthop Surg . 2011 ; 19 : 254 – 256 .
  5. Weltevrede HJ, Jansen BRH . Dysplasia epiphysealis hemimelica: three different types in the ankle joint . Arch Orthop Trauma Surg . 1988 ; 107 : 89 – 91 . doi:10.1007/BF00454492 [CrossRef]
  6. Bahk WJ, Lee HY, Kang YK, Park JM, Chun KA, Chung YG . Dysplasia epiphysealis hemimelica: radiographic and magnetic resonance imaging features and clinical outcome of complete and incomplete resection . Skeletal Radiol . 2010 ; 39 : 85 – 90 . doi:10.1007/s00256-009-0803-x [CrossRef]
  7. Bakerman K, Letts M, Lawton L . Dysplasia epiphysealis hemimelica of the ankle in children . Can J Surg . 2005 ; 48 : 66 – 68 .
Authors

The authors are from Helen DeVos Children’s Hospital and Michigan State University College of Human Medicine, Grand Rapids, Michigan.

The authors have no relevant financial relationships to disclose.

Correspondence should be addressed to: Philip D. Nowicki, MD, FAAP, Michigan State University College of Human Medicine, 35 Michigan St, Ste 4150, Grand Rapids, MI 49503 (pnowickikcms@gmail.com).

10.3928/01477447-20150402-01

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