Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities

Table 1 Accuracy of different imaging techniques in diagnosing talar osteochondral defects[1]

	Sensitivity	Specificity	Positive predictive value	Negative predictive value
Standard radiography	0.59	0.91	0.70	0.86
Heel-rise radiography	0.70	0.94	0.79	0.90
Computed tomography	0.81	0.99	0.96	0.94
Magnetic resonance imaging	0.96	0.96	0.89	0.99

The differences between computed tomography and magnetic resonance imaging were not statistically significant (P = 0.33).

Table 2 Overview of several radiographic and magnetic resonance imaging scoring systems for the ankle joint

Van Dijk Scale[33]	MOCART[41]
(0) Normal joint or subchondral sclerosis	Degree of defect repair and filling of the defect
(1) Osteophytes without joint space narrowing	Complete (on a level with adjacent cartilage)
(2) Joint space narrowing with or without osteophytes	Hypertrophy (over the level of the adjacent cartilage)
(3) (Sub)total disappearance or deformation of the joint space	Incomplete (under the level of the adjacent cartilage; underfilling)
	> 50% of the adjacent cartilage
	< 50% of the adjacent cartilage
Modified Takakura Scale[35]	Subchondral bone exposed (complete delamination or dislocation and/or loose body)
(1) No joint space narrowing but early sclerosis and osteophyte formation	Integration to border zone
(2) Narrowing of the joint space medially	Complete (complete integration with adjacent cartilage)
	Incomplete (incomplete integration with adjacent cartilage)
(3a) Obliteration of the joint space limited to the facet of medial malleolus with subchondral bone contact	Demarcating border visible (split-like) Defect visible
(3b) Obliteration of the joint space advanced to the roof of the talar dome with subchondral bone contact	< 50% of the length of the repair tissue > 50% of the length of the repair tissue
(4) Obliteration of the whole joint space with complete bone contact
Modified Kellgren-Lawrence Scale[34]	Surface of the repair tissue
(0) No radiographic findings of osteoarthritis	Surface intact (lamina splendens intact)
(1) Minute osteophytes of doubtful clinical significance	Surface damaged (fibrillations, fissures and ulcerations)
(2) Definite osteophytes with unimpaired joint space	< 50% of repair tissue depth
(3) Definite osteophytes with moderate joint space narrowing	> 50% of repair tissue depth or total degeneration
(4) Definite osteophytes with severe joint space narrowing and subchondral sclerosis
	Structure of the repair tissue
	Homogenous
	Inhomogenous or cleft formation
	Signal intensity of the repair tissue
	Dual T2-FSE
	Isointense
	Moderately hyperintense
	Markedly hyperintense
	3D-GE-FS
	Isointense
	Moderately hypointense
	Markedly hypointense
	Subchondral lamina
	Intact
	Not intact
	Subchondral bone
	Intact
	Non-intact (edema, granulation tissue, cysts, sclerosis)
	Adhesions
	No
	Yes
	Effusion
	No
	Yes

MOCART: Magnetic resonance observation of cartilage repair tissue; FSE: Fast spin-echo; 3D: Three-dimensional; FS: Fat-suppressed.