Should a patient with an osteochondroma be referred to an orthopaedic surgeon?

Osteochondroma Referral Decision

Orthopedic providers should preferably be involved in the monitoring of osteochondromas, with referral to orthopedic oncology indicated for symptomatic lesions, concerning features suggesting malignant transformation, or high-risk anatomic locations. 1

When to Refer to Orthopedic Surgery

Immediate Referral Indicated:

• Rapid growth of the lesion – suggests possible progression to chondrosarcoma 1
• Increasing or new-onset pain – warrants early investigation for malignant transformation 1
• Bulky cartilage cap >2.0-3.0 cm on MRI or CT – highly suspicious for chondrosarcoma 1
• High-risk anatomic locations – pelvis or scapula osteochondromas have higher transformation rates and should be referred for consideration of regional MRI surveillance every 2-3 years, particularly in males or EXT1 pathogenic variant carriers 1
• Vertebral/spinal lesions – risk of cord compression and neurological complications requires specialist evaluation 1
• Vascular complications – osteochondromas near vessels (especially around the knee) can cause arterial compression, occlusion, or venous complications requiring urgent surgical treatment 2, 3

Routine Orthopedic Involvement:

• Annual physical examinations starting in childhood are recommended for patients with hereditary multiple osteochondromas (HMO) 1
• Baseline skeletal survey at early adolescence (around age 12) when most osteochondromas have evolved, preferably by whole-body MRI or plain radiographs if MRI unavailable 1
• Orthopedic providers should preferably be involved in monitoring all osteochondromas, even if not requiring immediate surgical intervention 1

When Referral May Not Be Necessary

Solitary, asymptomatic osteochondromas with typical benign imaging features in low-risk locations may not require immediate orthopedic oncology referral and can be managed by general orthopedic surgeons with appropriate clinical and radiological follow-up 4. However, attention to key imaging and clinical findings is essential to correctly identify these benign lesions 4.

Critical Red Flags Requiring Urgent Evaluation

Malignant Transformation Risk:

• Malignant transformation to chondrosarcoma occurs in 0.2-5.9% of HMO patients, with 75% occurring between ages 20-40 years, though cases as young as 9 years have been reported 1
• Higher risk in males and EXT1 pathogenic variant carriers 1
• Transformation more common in pelvis and scapula 1

Non-Malignant Complications Requiring Referral:

• Bony deformities from growth disturbance 1
• Cord compression in vertebral lesions 1
• Vascular entrapment or compression – prophylactic resection recommended for osteochondromas near vessels 2, 3
• Symptomatic lesions causing functional impairment 5, 6

Special Populations

Hereditary Multiple Osteochondromas (HMO):

• These patients require more intensive surveillance with orthopedic involvement 1
• Spinal screening MRI should be considered, as spinal osteochondromas affect up to 68% of HMO patients, with 36% pooled incidence detected on imaging and 49% having intraspinal lesions 7, 8
• Most spinal lesions are asymptomatic but can cause significant neurological morbidity if undetected 7, 8

Syndromic Conditions (TRPS II, Potocki-Shaffer):

• Surveillance similar to HMO can be suggested, though not strongly recommended given rarity and unknown malignancy risk 1
• When symptomatic, imaging preferably by dedicated MRI with care in an academic center 1

Common Pitfalls to Avoid

• Do not dismiss persistent bone pain as trauma-related – a recent injury does not rule out malignancy and must not prevent appropriate diagnostic procedures 9, 10
• Do not rely solely on plain radiographs for surveillance of known osteochondromas – regular plain films of all lesions are not recommended due to high burden and low transformation frequency 1
• Do not delay referral for suspected malignancy – all patients with suspected primary malignant bone tumors should be referred to a bone sarcoma reference center before biopsy 10, 9, 10
• Do not overlook skin changes – hyperkeratotic skin overlying a bone lesion may mimic verruca vulgaris but could indicate underlying osteochondroma 6