Close's 1956 cadaveric study asks a deceptively simple question: what actually has to tear before the ankle mortise visibly widens on X-ray? Using progressive ligament sectioning in 10 fresh specimens and an illustrated clinical case series, he maps the relationship between specific ligamentous injuries and radiographic diastasis.
Any medial clear space widening >2 mm tells you the deltoid is torn — not stretched, not contused, but torn. This is not a soft sign; it is a biomechanical certainty established by this paper.
When you see a lateral malleolus fracture and the medial clear space won't close with manipulation or after fibular fixation, the deep deltoid is almost certainly interposed. Fixing the fibula alone will fail in this scenario.
Your operative plan must include a posterior J-incision at the medial malleolus, retraction of the PTT anteriorly, extraction of the trapped deep deltoid from the joint, and direct repair. Repairing only the visible superficial layer is the classic error that leaves residual widening.
Place a syndesmotic screw to hold the mortise at physiological tension while the deltoid heals. But counsel the patient and schedule removal, because the 1.5 mm of normal intermalleolar motion during dorsiflexion will break a retained screw.
Close's 1956 cadaveric study asks a deceptively simple question: what actually has to tear before the ankle mortise visibly widens on X-ray? Using progressive ligament sectioning in 10 fresh specimens and an illustrated clinical case series, he maps the relationship between specific ligamentous injuries and radiographic diastasis.
Any medial clear space widening >2 mm tells you the deltoid is torn — not stretched, not contused, but torn. This is not a soft sign; it is a biomechanical certainty established by this paper.
When you see a lateral malleolus fracture and the medial clear space won't close with manipulation or after fibular fixation, the deep deltoid is almost certainly interposed. Fixing the fibula alone will fail in this scenario.
Your operative plan must include a posterior J-incision at the medial malleolus, retraction of the PTT anteriorly, extraction of the trapped deep deltoid from the joint, and direct repair. Repairing only the visible superficial layer is the classic error that leaves residual widening.
Place a syndesmotic screw to hold the mortise at physiological tension while the deltoid heals. But counsel the patient and schedule removal, because the 1.5 mm of normal intermalleolar motion during dorsiflexion will break a retained screw.