Acute pain in the right ankle.
A 60 year old male patient attended the Emergency Room complaining about acute onset of pain in the right ankle, following a mild trauma during his morning walk.
Radiologic evaluation of the right ankle revealed no fracture, though multiple osteochondromas of the distal fibula and tibia were identified (Figure 1). The patient had a known history of diaphyseal aclasis (DA). Physical examination of the knees and ankles revealed asymptomatic masses at the distal femurs, as well as the proximal and distal fibulas and tibias. Radiographs of the left ankle (Figure 2) and both knees (Figures 3, 4) revealed multiple exostoses with significant bone deformities. The patient had been aware of these lesions since his childhood, whereas his father was also known to have similar skeletal outgrowths. No chronic pain or other significant information were mentioned in the clinical history, apart from limited range of movement in the left knee joint. Radiologic evaluation with plain films obtained 7 years earlier revealed no change.
DA or Hereditary Multiple Exostoses is an inherited autosomal dominant disorder with incomplete penetrance in which multiple osteochondromas are seen throughout the skeleton. The estimated prevalence of DA is 1:50 000 to 1:100 000 in Western populations. Approximately two-thirds of affected individuals have a positive family history whereas the remaining cases are attributed to new mutations. The specific genetic abnormalities have been detected within three distinct loci on chromosomes 8, 11 and 19 designated respectively as EXT1, EXT2 and EXT3 [1,2]. Virtually all patients are diagnosed by the age of 12 years [2].
Osteochondromas are developmental anomalies resulting from the fragmental separation of the epiphyseal growth plate cartilage. Subsequent growth and enchondral ossification result in a subperiosteal osseous excrescence either sessile or pedunculated, with a cartilage cap that projects from the bone surface. The stalk of the osseous protuberance is in direct continuity with the underlying cortex and medullary canal. Upon skeletal maturity growth ceases [2].
In DA, any bone preformed in cartilage (enchondral ossification) may develop osteochondromas, with the exception of the calvaria. Specific sites include the scapula and ribs (40% of cases), humerus (50%–98%), elbow (35%–40%), wrist (30%–60%), hands (20%–30%), pelvis (5%–15%), hips (30%–90%), knees (70%–98%), ankles (25%–54%), and feet (10%–25%)[2].
Complications include osseous deformities, fractures, short stature, limb length discrepancy, pseudo-Madelung deformity, neurovascular compromise, bursa formation and sarcomatous transformation (chondrosarcoma or, rarely, osteosarcoma)[2].
Plain radiography remains the examination of choice in the evaluation of osteochondromas which are depicted as well marginated pedunculated or sessile bony excrescences. Continuity with the cortex and spongiosa of the parent bone is pathognomonic. Pedunculated exostoses in tubular bones tend to be round or pointed and extend from the metaphyses toward the diaphyses, away from the joint. Metaphyses often become irregularly expanded and club-shaped. The cartilage cap may contain punctate, flocculent, comma-shaped, arclike or ringlike calcifications [2,6].
CT is complementary in the assessment of osteochondromas in the pelvis, shoulder, or spine. Using three-dimensional CT imaging, reconstructions can be formatted in various planes [2]. Ultrasonography is valuable in the diagnosis of bursitis and other complications associated with osteochondromas, such as arterial or venous thrombosis, aneurysm, and pseudoaneurysm formation [2]. MRI is useful for assessing accurate measurements of the cartilage cap which has high signal intensity on T2-weighted spin-echo images. Cap thickness more than 1,5 cm in skeletally mature patients suggests malignant transformation. It is the method of choice for evaluating compression of the spinal cord, nerve roots, and peripheral nerves [2,3]. Scintigraphy with thallium Tl 201 is useful in differentiating malignant transformation from benign osteochondroma in DA [4]. A normal isotopic bone scan virtually excludes the possibility of malignant transformation [5].
Diaphyseal Aclasis
Based on the provided X-ray images of the right ankle (lateral, oblique views, etc.), the following main features can be observed:
• A prominent bony outgrowth (exostosis) is seen around the distal area of the talus (possibly near the distal tibia or fibula), appearing as a bony lesion continuous with the cortex and marrow cavity.
• These bony protrusions (which can be pedunculated or broad-based) have well-defined boundaries. Continuity of the cortical bone extending into the protrusion is visible; if calcification exists in the cartilaginous cap, punctate or ring-like calcifications may be noted.
• The joint space appears largely preserved, but the local outgrowth may interfere with joint motion, suggesting potential involvement of soft tissues and joint structures.
• No obvious acute fracture signs are noted. However, given the patient’s complaint of acute ankle pain, it is necessary to rule out mechanical irritation, inflammation, or a minor fracture around the protrusion in the surrounding soft tissue or joint capsule.
Taking into account the patient’s profile (60-year-old male), unknown family history, and the X-ray features, the potential diagnoses or differential diagnoses include:
Considering the patient’s age, the typical imaging features of the ankle bony outgrowth (continuity with the marrow cavity and cortex), and the potential for multiple lesions, the most likely diagnosis is:
Hereditary Multiple Exostoses (Multiple Osteochondromas, HME).
To further clarify the diagnosis, the following are recommended:
• Further inquiry about family history to determine if similar bony outgrowths exist;
• Additional MRI examination to measure the cartilage cap thickness and evaluate possible compression of adjacent soft tissues, joint, and neurovascular structures;
• In cases suspicious for malignant transformation or progressively worsening pain, biopsy or advanced imaging assessment may be considered.
Treatment Strategy:
• Conservative Management: For outgrowths with no obvious risk of malignancy and mild symptoms, the use of protective gear, avoidance of excessive loading and impact, and periodic follow-up are recommended.
• Medication and Physical Therapy: If there is local inflammation or pain around the joint or the outgrowth, consider anti-inflammatory analgesics or physical therapy (e.g., ultrasound, physiotherapy, hot compresses).
• Surgical Intervention: Surgery may be required when the exostosis affects joint function, causes significant pain, compresses neurovascular structures, or if malignancy is suspected. During resection, it is important to preserve joint function and avoid excessive damage to the articular surface.
Rehabilitation and Exercise Prescription:
Once pain subsides and there are no contraindications for surgery, a progressive exercise program can be developed (based on the FITT-VP principle):
If the patient has fragile bones, compromised cardiopulmonary function, or other comorbidities, exercise intensity and content should be carefully monitored. A multidisciplinary team comprising orthopedics, rehabilitation, cardiology, etc., may be necessary to develop an individualized plan.
This report is a reference analysis based on the currently provided information and cannot replace an in-person consultation or the professional diagnosis and treatment advice of a qualified physician. Should any further symptoms arise or concerns persist, consult a specialist without delay and undergo any necessary examinations and treatments.
Diaphyseal Aclasis
