A 3-year-old boy presented to orthopaedics outpatient clinic with a history of painless bony swelling limited to medial side left ankle joint for the past few months.
A 3-year-old boy presented to orthopaedics outpatient clinic with a history of painless bony swelling limited to medial side left ankle joint for the past few months. On examination a painless hard mass was palpable at the medial aspect of left ankle with good range of ankle movements. There was no leg length discrepancy. The family history was unremarkable. Plain radiographs suggested an osteochrondroma following which an excision biopsy done which confirmed the same. The swelling has recurred rapidly in about 12 month’s time following the excision. At surgery for re-excision, it involved the growth plate on the tibial side and also the dome of the talus. Further plain radiographs showed a classic radiographic appearance of asymmetric medial epiphyseal overgrowth with a well-structured accessory epiphyseal ossification centre over the medial talar dome separate from the genuine epiphysis. A radiological diagnosis of Dysplasia Epiphysealis Hemimelica was supported by histological appearance of osteochondroma. The swelling recurred shortly following re-excision after which it was decided manage the patient conservatively with no further surgical intervention.
Dysplasia Epiphysealis Hemimelica (DEH) is characterised by asymmetrical abnormal cartilage proliferation and associated endochondral ossification (osteocartilaginous growth) in an epiphysis or in a tarsal, carpal or flat bone. Mouchet and Belot first described it in 19261,8. In the English literature it was first reported by Trevor, who called it tarsoepiphyseal aclasis or Trevors Disease2,6. Because of the predisposition to either the medial or lateral half of a single limb, Fairbank proposed the name Dysplasia Epiphysealis Hemimelica in 1956 which is the most commonly used term4, 5, 8. The aetiology is unknown, and DEH is extremely rare with a prevalence of one per million. No hereditary or familial factor has been demonstrated. M: F ratio of 3:1. DEH predominantly affects the lower extremity (usually a single extremity), with very rare upper extremity involvement of humerus, ulna, and scapula1,7. DEH is usually restricted to the medial or lateral side of the limb (hemimelic). The medial side affected twice as frequently as the lateral. Azouz et al subdivided this congenital hamartomatous disorder in to three different types1, 2, 4: 1) the classical form, characterised by hemimelic distribution or epiphyseal osteochondromas usually affecting a single lower extremity (monomelic) and commonly seen in the knee and ankle. This accounts for more than two-thirds of cases, 2) the generalised or severe form, with involvement of the entire extremity most commonly the lower extremity; and 3) the localized form, with monoarticular localisation most commonly occurring in ankle or hind foot. Radiology: Classic radiographic appearance of asymmetric epiphyseal overgrowth with multiple ossific centres. Irregular multicentric, coalescent radio-opacities incorporated into epiphyseal ossification, or a well-structured accessory epiphyseal ossification centre merging with or being separated from the genuine epiphysis. Physis may close prematurely resulting in limb deformity and limb length discrepancy. The articular surface is often irregular and, combined with the angular deformity. This frequently results in premature secondary osteoarthritis1, 5.6,8. Under-tubulation of bone may occur due to secondary involvement of metaphysis1. CT scanning has been used to more accurately define the anatomy of the epiphysis and joints. However, CT demonstration of soft tissues and cartilage is limited. Also, the relationship in planes other than axial is better evaluated with MR imaging1, 8. MRI depicts the un-ossified cartilaginous mass in great detail, as well as the status of the articular cartilage, and helps to differentiate the abnormal epiphyseal growth from the main epiphysis1, 3. The lesion and involved epiphyseal cartilage have similar signal intensity, with intermediate signal intensity on T1-weighted and high signal intensity on T2-weighted MR images. Areas of low signal intensity on T1- and T2-weighted images indicate areas of calcification or ossification that increase as the lesion and patient's skeletal maturity progresses1, 2, 3. Radiological features are diagnostic & biopsy is usually not necessary. However, a skeletal survey should be performed to exclude additional areas of involvement, particularly of the lower extremities1. Surveillance and clinical assessment are usually continued until the patient reaches skeletal maturity to assess the progression of the disease.
Dysplasia Epiphysealis Hemimelica (DEH)
Based on the provided left ankle X-ray, the following findings can be observed:
1. Irregular bony proliferation or osteochondral-like protrusion is noted in the epiphyseal region on the medial side of the left ankle joint (distal tibia or medial half of the talus).
2. The lesion shows a multi-centric pattern of increased density, partly fused with the epiphysis or showing local separation. The adjacent normal epiphysis appears slightly irregular in comparison.
3. Slightly irregular joint surface development is observed, with no evident acute fracture line. The joint space is essentially normal.
4. No obvious signs of soft tissue swelling or fracture displacement are currently observed.
5. Overall imaging suggests an asymmetric excessive proliferation of the epiphysis, resembling an “osteochondroma-like” lesion, but confined to the medial half of the joint area.
Based on the patient’s age (3 years old), the lesion located at the medial half of the epiphysis, and the X-ray findings of epiphyseal overgrowth and morphological characteristics, the following potential diagnoses can be considered:
1. Epiphyseal Dysplasia (Dysplasia Epiphysealis Hemimelica, DEH): Also known as Trevor disease, it is commonly seen in children. The lesion is typically restricted to the medial or lateral half of the epiphysis in a single joint, presenting as excessive epiphyseal growth and irregular ossification centers. It frequently affects weight-bearing joints such as the ankle and knee.
2. Osteochondroma: Often occurs at the metaphysis or adjacent to the epiphysis, but if close to the intra-articular epiphysis, it may present as an osteochondral-like protrusion. Generally, osteochondromas appear more frequently in the metaphysis, projecting outward, with less involvement of the articular surface.
3. Chondroblastoma: Mostly seen in adolescents, but often involving the epiphyseal region. It can present as localized irregular bone destruction or bony proliferation, with or without calcification. However, pain or swelling is common in chondroblastoma, whereas in this case the patient has a painless mass.
Combining the patient’s clinical features (3-year-old boy, lesion primarily confined to the medial half of the ankle joint, painless bony mass) with the typical X-ray findings (asymmetric, hemiepiphyseal overgrowth, and irregular ossification centers), the most likely diagnosis is: Dysplasia Epiphysealis Hemimelica (DEH).
This is an extremely rare congenital abnormality of epiphyseal development. Patients often present with an asymmetric mass in a single joint (especially the ankle or knee), distinguishing it from other possible conditions. This diagnosis best fits the presentation in this case.
1. Treatment Strategy:
- Regular Follow-up/Observation: For children without obvious functional impairment or deformity, observation through regular follow-up is often sufficient to evaluate skeletal growth and the progression of any deformity.
- Surgical Intervention: If the lesion causes joint dysfunction, lower limb malalignment, severe deformity, or pain, surgical treatment (e.g., curettage of the lesion, excision of bony outgrowth, or reconstruction of the joint surface) may be indicated. Postoperative assessment of skeletal maturity is essential to minimize the risk of secondary deformity or joint damage.
- Rehabilitation Therapy: Physical therapy can assist with improving or maintaining range of motion, muscle strength, and overall ankle joint function.
2. Rehabilitation/Exercise Prescription (FITT-VP Principle):
- Frequency (F): 2-3 times per week initially, progressively increasing to 4-5 times per week according to the child’s tolerance.
- Intensity (I): Low to moderate intensity (e.g., passive ankle movements, light resistance band exercises), avoiding excessive load on the joint.
- Time (T): About 10-15 minutes per session initially, extendable to 20-30 minutes as the child grows and progresses in rehabilitation.
- Type (T): Focus on activities that maintain ankle stability and stimulate normal development, such as water therapy, seated ankle flexion-extension exercises, and safe balance exercises (e.g., using a balance pad).
- Progression (P): As the child develops and shows rehabilitative improvement, incrementally increase exercise intensity or duration (e.g., introduce moderate squatting and single-leg balance), under professional supervision.
- Volume & Progression (VP): Reevaluate every 4-6 weeks based on the child’s tolerance and development, gradually increasing the exercise regimen while ensuring joint stability and avoiding secondary injuries.
This report is a preliminary analysis based on the current imaging and patient history, and is for reference only. It does not replace in-person consultation or professional opinions of orthopedic specialists. Specific treatment plans and rehabilitation details require comprehensive assessment by a professional medical team, based on the child’s actual condition.
Dysplasia Epiphysealis Hemimelica (DEH)
