Pott's fracture | |
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Classification and external resources | |
ICD-10 | S82.6 |
ICD-9 | 824.4-824.5 |
Pott's fracture, (not to be confused with Pott's disease), also known as Pott’s syndrome I and Dupuytren fracture, is an archaic term loosely applied to a variety of bimalleolar ankle fractures.[1] The injury is caused by a combined abduction external rotation from an eversion force. This action pulls on the extremely strong medial (deltoid) ligament, often tearing off the medial malleolus. The talus then moves laterally, shearing off the lateral malleolus or, more commonly, breaking the fibula superior to the tibiofibular syndesmosis. If the tibia is carried anteriorly, the posterior margin of the distal end of the tibia is also sheared off by the talus. A fractured fibula in addition to detaching the medial malleolus will tear the tibiofibular ligament.[2] The combined fracture of the medial malleolus, lateral malleolus, and the posterior margin of the distal end of the tibia is known as a "trimalleolar fracture." [3] Note that in a "trimalleolar fracture" that the posterior distal end of the tibia is erroneously labeled as a malleolus. A real life example of this would be the foot everting in a football tackling sport's injury. In this injury, a person's ankle receives a lateral force pushing the fibula towards the tibia. The player, on the ground, responds with the force of eversion force from the calcaneous to lesson the initial lateral force. The eversion of the foot twists the fibula from its rest position into the plane where the lateral force originated. To come out of its plane, it must pivot from a certain point to accomplish this rotation. That pivot point is where the fracture would occur. This pivot point, since it is above the anterior tibiofibular ligament, would consequently tear. Better imagine this was as two hands on a clock, one hand facing 12, the other facing 6. Both hands are the fibula of the person's right leg. The lateral force approaches from 3 o'clock. The hand pointing at the 6 everts to the position at 5 (thus laterally) to compensate and thus must in order to occur fracture at its pivot point.[2]
The bimalleolar fractures are less likely to be arthritic than trimalleolar fractures.[4]
English physician Percivall Pott experienced this injury in 1765 and described his clinical findings in a paper published in 1769.[5][6]
The term "Dupuytren fracture" refers to the same mechanism,[7] and it is named for Guillaume Dupuytren.[8]
Pott did not describe disruption of the tibio-fibular ligament, whereas Dupuytren did.
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