Jm. Hartford et al., TIBIOTALAR CONTACT AREA - CONTRIBUTION OF POSTERIOR MALLEOLUS AND DELTOID LIGAMENT, Clinical orthopaedics and related research, (320), 1995, pp. 182-187
Sixteen fresh ankle specimens were tested under physiologic loads to e
valuate the effect on the tibiotalar contact area of increasing-size p
osterior malleolar fracture fragments and disruption of the deltoid li
gament, The tibiotalar joint was maintained in a neutral position, and
contact areas were recorded on pressure sensitive film, Posterior mal
leolar fracture fragments of 25%, 33%, and 50% as visualized on latera
l radiographs were created, The deltoid ligament was sectioned after t
he final fracture fragment was made, There was a corresponding decreas
e of 4%, 13%, and 22% in tibiotalar contact area with the increasingly
larger fracture fragments. The final disruption of the deltoid ligame
nt did not alter the contact area, Statistical analyses using Student'
s t-test showed a statistically significant decrease in tibiotalar con
tact area in the samples with a fracture fragment of 33% and 50% invol
vement of the joint as compared with the control samples, Transection
of the deltoid ligament produced no statistically significant further
change in contact area. Displaced posterior malleolus fractures produc
e a significant decrease in contact area with 33% or greater involveme
nt of the joint, which may predispose the tibiotalar joint to degenera
tive changes that should be lessened by anatomic reduction and interna
l fixation, Disruption of the deltoid ligament does not appear to alte
r contact area further, supporting the concept of repair as optional.