TABLE III.

Classification Systems for OCD of the Talus^*

Radiography	CT	MRI	Arthroscopy
Berndt and Harty251 (1959) Stage 1: Small subchondral compression Stage 2: Partially detached osteochondral fragment Stage 3: Completely detached but nondisplaced fragment Stage 4: Completely detached and displaced fragment (loose body) Scranton and McDermott modification252 (2001) Stage 5: Subchondral cyst	Ferkel et al.216 (2008) Stage I: Cystic lesion within dome of talus, and intact roof on all views Stage IIA: Cystic lesion with communication to talar dome surface Stage IIB: Open articular surface lesion with overlying nondisplaced fragment Stage III: Nondisplaced lesion with radiolucency Stage IV: Displaced fragment Other classification systems: Loomer et al.124 (1993)	Hepple et al.262 (1999) Stage 1: Articular cartilage damage only Stage 2a: Cartilage injury with underlying fracture and surrounding osseous edema Stage 2b: Stage 2a without surrounding osseous edema Stage 3: Detached but nondisplaced fragment Stage 4: Detached and displaced fragment Stage 5: Subchondral cyst formation	Ferkel et al.216 (2008) Grade A: Smooth, intact, but soft or “ballottable” (springy) Grade B: Rough surface Grade C: Fibrillations and/or fissures Grade D: Flap present or bone exposed Grade E: Loose, nondisplaced fragment Grade F: Displaced fragment Other classification systems: Pritsch et al.263 (1986)

^*CT = computed tomography, and MRI = magnetic resonance imaging.