Features of Osteochondroma
Mnemonic: Six “C”
- Commonest benign bone tumor
- Continue to grow until Closure of physis
- Cartilage cap (appears larger clinically than in X-ray)
- Continuous with native bone (cortex and medullary canal)
- Cane (pedunculated/stalked points away from joint and sessile/broad based have higher risk of malignant degeneration)
- Change (mutation) in EXT1, EXT2 and EXT3 genes
![osteochondroma](https://epomedicine.com/wp-content/uploads/2022/10/Osteochondroma_X-ray.jpg)
Complications
Mnemonic: ABCDE
- Adventitious bursa (pain)
- Breakage of stalk (pain)
- Chondrosarcoma (pain; risk: 1% in solitary osteochondroma and 10% in multiple osteochondroma)
- Deformities:
- Femoral shortening
- Coxa valga
- Genu valgum, Ankle valgus (because of shortened fibula)
- Patellar dislocation
- Ulnar shortening, radial bowing and ulnar deviation of hand
- Radial head dislocation
- Encroachment:
- Nerve compression (sciatic, common peroneal, radial)
- Pseudoaneurysm (popliteal artery)
- Tendon (rotator cuff impingement, subscapularis tear, bicipital tendinitis)
Common locations
Mnemonic: FGH
- Femur (proximal)
- Genu (knee)
- Humerus (proximal)
- Hallux (subungual)
Risk factors for Malignant transformation
Mnemonic: GLAD PaST
- Growth after skeletal maturity
- Lucency (new)
- Additional scintigraphic activity
- Destruction (cortical)
- Pain after puberty
- Soft tissue mass
- Thickened cartilage cap >1.5 cm
Pathogenesis theories
Mnemonic: Five “P”
1. Bone defect
- Perichondral bone defect and (Keith)
2. Cartilaginous metaplasia
- Periosteal metaplasia in periphyseal-perimetaphyseal area producing cartilage (Muller)
3. Displacement of physis
- Peripheral part of physis displacement (Virchow)
4. Epiphysis retains chondrogenic potential
- Pathological retainment of chondrogenic properties by the epiphysis that would form perichondral bone of the groove of ranvier (Langenskiold)
5. Failure of tubulation
- Prominent metaphysis suggesting tubulation failure (Jansen)
![dr. sulabh kumar shrestha](https://epomedicine.com/wp-content/uploads/2020/07/profile.jpg)
He is the section editor of Orthopedics in Epomedicine. He searches for and share simpler ways to make complicated medical topics simple. He also loves writing poetry, listening and playing music.