The other important structures that were released medially are abductor hallucis, superficial part of deltoid ligament
, spring ligament, master knot of Henry and capsulotomies of subtalar, talonavicular, naviculocuneiform and cuneiformo-metatarsal joints.
Also important to consider is the close approximation of the posterior tibial and flexor hallucis tendons to the deltoid ligament as their tendon sheaths are essentially contiguous with the insertions of the deltoid ligament complex.
In the anatomical arm of the study, cadaver ankles underwent stress testing after an isolated deltoid ligament division, isolated medial malleolus fracture, isolated division of the fibular collateral ligaments, and a short oblique distal fibula osteotomy with all ligaments intact.
Forty-six ankles, therefore, underwent operative fixation of the medial malleolus or suture repair of the deltoid ligament without fibular fixation in any of the fractures.
Criteria for inadequate reduction were set as follows: lateral malleolar displacement greater than 2 mm on the AP or lateral, medial malleolar displacement of greater than 1mm on the AP only, deltoid ligament disruption with more than 3 mm medial clear space, syndesmosis injury with tibia-fibula clear space greater than 5 mm or tibia-fibula overlap of less than 10 mm (both on the AP), or a tibia-fibula overlap of less than 1 mm on the mortise view.
Their conclusions stated that bimalleolar ORIF provided far superior results than closed treatment of ankle fractures, and that patients with a medial malleolar fracture (as opposed to just a deltoid ligament rupture) faired significantly worse when treated by closed reduction.
Intraoperatively we noticed that there was near total avulsion of the deltoid ligament with only a few fibres of periosteum intact anteriorly.
O'Leary and Ward described a high velocity injury caused by initial abduction external rotation followed by violent adduction leading to avulsion of the deltoid ligament and fracture of the medial malleolus respectively.
The deltoid ligament provides the medial ligamentous support of the ankle.
The disruption of the deltoid ligament rarely needs to be surgically addressed.