(ROTATIONAL ANKLE FRACTURE)
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related talks: broken foot (talus fracture, another type); broken foot (jones fracture); broken heel bone; low ankle sprain; high ankle sprain
What is an Ankle Fracture?
An ankle fracture is one of the most common fractures and it occurs with an excessive twisting motion to the ankle.
The most common injury is for the foot to roll inward (supination) while the ankle twists outward (external rotation).
The fibula (which forms the outer ankle) is the more commonly broken bone, but the inside ankle (the tibia bone) or both inside and outside ankles can be also brake. Most of the ankle fractures will also be accompanied by some form of ligament injury. The severity of injury depends on the position of the foot when the injury occurs and also the force of the twisting motion.
As a quick review of the ankle anatomy (see picture), this joint consists of three bones: the two leg bones (the tibia which is the large bone in the leg, and the smaller fibula, which only bears about 10% of the weight) and the one foot bone (the talus). The tibia forms the inside ankle (called the medial malleolus) and is connected to the foot by a very thick ligament called the “Deltoid Ligament” which often gets torn during an ankle fracture. The fibula forms the outside ankle (called the lateral malleolus) and this is connected to the foot by two ligaments, the ATFL (which is injured in your common ankle sprains) and the CFL. The fibula and tibia are held together by a very thick ligament complex called the “Syndesmosis”, which can sometimes be torn in ankle fractures (it is also the ligament injured when we talk about “high ankle sprains”).
How is an Ankle Fracture diagnosed?
An ankle fracture is suspected when someone describes a twisting injury to their ankle. However, ankle sprains occur the same way and are much more common than fractures, and ankle sprains dont require x-rays (doctors try to avoid taking unnecessary x-rays to minimize radiation exposure). When examining the ankle, certain findings, such as tenderness within 6 cm of the ankle prominence or the inability to take more than 4 steps on the injured leg, suggest a fracture, and requires an x-ray. Three views by x-ray is typically sufficient to show a fracture. The fracture pattern will be different depending on the direction the ankle turned (in fact, doctors can look at an x-ray of a broken ankle and know exactly how the foot twisted at the time of injury). If the lateral ankle (fibula bone) is broken, yet the inside ankle (tibia) is intact, an additional x-ray is typically ordered to determine ankle stability. This extra x-ray (called a “stress view”) is helpful for determining treatment (if surgery is necessary).
How is an Ankle Fracture treated?
Even though an ankle fracture is one of the most common injuries in orthopedics, there is a lot of controversy about the ideal treatment. Most surgeons will agree that if both the inside and the outside ankle is broken (the fibula and the tibia), then surgery is recommended to ensure the correct alignment of the joint, thereby minimizing the risk of future arthritis. The surgery involves using a metal plate and a few screws to hold the bone in the correct position while it heals. The hardware is usually left inside the person after surgery, however it can be removed at a later time if it causes irritation, or if you just don’t like the idea of having metal inside your leg. The bigger controversy in treatment is how to address a fracture of just the outside ankle (the lateral malleolus). Oftentimes, the outer ankle is broken and the “stress view” is abnormal. This indicates that even though there is not fracture to inner ankle, there is a significant inner ligament tear, which makes the overall ankle unstable. In such cases, most surgeons recommend repairing the fracture to realign the ankle and return its stability. However, some surgeons will say that this ankle will heal well if it is treated in a cast for 4-6 weeks as long as the correct alignment can be obtained and held in position with the cast.
Lastly, there is another scenario, when just the outer ankle is broken, but this time the “stress view” is normal (indicating the overall ankle remains stable, there is no inner ligament damage). In this case, as long as the fracture fragment has not displaced (moved out of position more than a few millimeters), then surgery is not necessary, in fact a person with this fracture can typically begin walking on the leg, with a protective boot, as soon as the pain is tolerable. Whats interesting is that an injury to the inner ligament (deltoid ligament) may be the only difference between having surgery or walking out of the emergency room. Its a great example of how important ligaments are to providing stability to our joints.
What is the long term outcome?
Overall these injuries heal very well, with about 90% of people happy with their results. However, sometimes it takes a while for people to return to their preinjury activity, and its not uncommon for it to take 1 year to return to normal. People are typically allowed to return to driving 9 weeks after their surgery (see blog post), but overall return to driving and other activities is determined by the surgeon treating the injury.
1) Michelson JD. Ankle fractures resulting from rotational injuries. JAAOS 2003; 11: 403-12. review.
2) Zalavras C, Thordarson D. Ankle syndesmotic injury. JAAOS 2007; 15: 330-9. full article. review.
3) Shah AS et al. Radiographic evaluation of the normal distal tibiofibular syndesmosis. FAI 2012; 33: 870-6. full article. evaluating normal syndemosis, reliability of tib-fib overlap.
4) Kwon JY et al. A novel methodology for the study of injury mechanism: ankle fracture analysis using injury videos posted on YouTube.com. JOT 2010; 24: 477-82. full article. PER has unpredictable fracture pattern. SAD is predictable. overall lauge-hanson is flawed.
5) Summers HD et al. A reliable method for intraoperative evaluation of syndesmotic reduction. JOT 2013; 27: 196-200. full article.
6) DeAngelis NA et al. Does medial tenderness predict deep deltoid ligament incompetence in supination-external rotation type ankle fractures? JOT 2007; 21: 244-7. full article.
7) McConnell T et al. Stress examination of supination external rotation-type fibular fractures. JBJS 2004; 86: 2171-8. full article. exam is poor predictor, need stress x-ray.
8) Gill JB et al. Comparison of manual and gravity stress radiographs for the evaluation of supination-external rotation fibular fractures. JBJS 2007; 89: 994-9. full article. no difference in manual vs. gravity.
9) Nielson JH et al. Radiographic measurements do not predict syndesmotic injury in ankle fractures: an MRI study. CORR 2005; 436: 216-21. full article. look at 71 ankle fractures with x-ray and mri. medial clear space >4mm correlated with deltoid injury. tib-fib overlap/clear space had no correlation with syndesmotic injury. level of fibula fracture didnt correlate with syndesmosis injury.
10) Park SS et al. Stress radiographs after ankle fracture: the effect of ankle position and deltoid ligament status on medial clear space measurements. JOT 2006; 20: 11-8. full article. best criteria is >5 mm, changes in space 2-3 mm is less predictive.
11) Wikeroy AK et al. No difference in functional and radiographic results 8.4 years after quadricortical compared with tricortical syndesmosis fixation in ankle fracture. JOT 2010; 24: 17-23. full article. no difference in 3 or 4 cortex screws.
12) Pettrone FA et al. Quantitative criteria for prediction of the results after displaced fracture of the ankle. JBJS 1983; 65: 667-77. full article. orif does better than nonop.
13) van den Bekerom MP et al. Which ankle fractures require syndesmotic stabilization? J Foot Ankle Surg 2007; 46: 456-63. full article.
14) Jenkinson RJ et al. Intraoperative diagnosis of syndesmosis injuries in external rotation ankle fractures. JOT 2005; 19: 604-9 full article.
15) Chu A, Weiner L. Distal fibula malunions. JAAOS 2009; 17: 220-30. full article. review of complications.
16) Egol KA et al. Braking function after complex lower extremity trauma. JOT 2008; 65: 1435-38. full article. in general brake times start to normalize 6 wks after starting weight bearing.