By Doug James, intraining Physiotherapist and Podiatrist

Ankle sprains are a common injury ^[2,3], and they tend to hurt – at least a little bit. While most minor sprains tend to heal well, all ankle sprains should be assessed to differentiate the sprain type and severity and to determine the recovery period ^[3,4] as returning to sport too soon comes with the risk of long-term consequences ^[2].

What is an ankle sprain?

Ankle sprains occur when your foot rapidly rolls excessively and strains (or ruptures) the fibres in the ligaments attaching your ankle to the side of your foot. The inner (medial) side of the ankle has strong ligaments, however, the outer (lateral) side of the ankle is less well supported and is prone to injury when the ankle rolls over the outside of the foot^[2] (yet another design flaw in the human body). This tends to happen commonly in stop-start sports such as basketball or soccer^[2], but runners – particularly trail runners susceptible to this injury. Where damage occurs to the ligaments, this is graded on a 3-point scale from mild to severe based on injury history and clinical tests, with diagnostic imaging used occasionally to provide further insight.

Mild sprains (Grade 1)

In mild cases (Grade 1) the lateral (outside) ankle ligaments may be stretched or slightly damaged, some pain is felt usually at the time of the injury and usually improves over the course of a few days. Some swelling is expected and bruising may or may not occur during this time.

Moderate sprains (Grade 2)

Moderate, or Grade 2 injuries are generally painful for longer as there is a larger degree of damage to one or more of the three ligaments. Walking can prove difficult due to pain, and the ankle will likely be swollen with bruising developing that may last for a couple of weeks on the side of the foot, ankle and/or lower leg.

Severe sprains (Grade 3)

Grade 3 (severe) injuries can sometimes be less painful than Grade 2 injuries as the completely ruptured ligament(s) tend to stop hurting after a couple of days. The ankle is significantly less stable due to the lack of supporting ligament support and can progress on to long term injury if not properly treated.

Early treatment for Lateral Ankle Sprains

Initial treatment should begin as soon as possible and involves protecting the injury from further damage. If the ankle is significantly sore, it is best not to continue to run with the injury as pain and the resultant reduction in reflexes will force changes in gait and may make the injury grade worse. While the use of ice packs has been challenged more recently (arguments have been made that this can slow healing) they can be useful for reducing pain. Compression and elevation are accepted treatments and should be administered ASAP. Early mobilisation (walking) is useful in most cases as it encourages faster healing, but should be done in moderation over the first couple of days. X-rays are generally only required if you are unable to stand on that foot due to pain, and there is tenderness on the bony parts of the side of the foot or ankle. Pain in these locations can be indicative of a fracture and should be treated with additional care with a fracture boot, plaster cast or occasionally surgery.

Return to sport rehabilitation

It’s been shown that all grades of ankle sprains result in reduced strength and balance in that ankle ^[2]. Failure to address these deficits results in a higher than average likelihood of re-injury, and possibly a more severe grade injury. Additionally, other injuries to the ankle or leg can result. A good rehabilitation plan will include a personalised program aimed at addressing your particular deficits and restrictions present at assessment. This should be reviewed through the course of the rehabilitation process to ensure the exercises are suitably challenging and are being performed correctly. Returning to running (or sport) may happen as early as one week post sprain for lower grade injuries, though this should be done at an easy intensity and for a short amount of time. In cases where the initially diagnosed Lateral Ankle Sprain is persistently painful, or not responding to a rehabilitation program, suspicion a more complex ankle sprain should be raised. These types of injuries are discussed below and may require further imaging ^[5].

Avulsion Fractures

Ankle sprains that make standing unbearable are complicated by possible fracturing of bones in the foot, ankle or lower leg. When the ankle rolls during a sprain there is often a forceful muscle contraction that can pull bone away from the muscle insertion. This tends to occur on the lumpy part of the side of the foot (styloid process and/or fifth metatarsal shaft). In other cases, the bone fragment may be avulsed due to the ligament attachment pulling it away from the main bone. This can happen on the inside and outside aspects of the ankle, and rarely on the proximal fibula (just below the knee on the outer side of the leg). Detection of the fracture is usually done with X-ray at the time of the injury, and sometimes 2 weeks later if the initial scan is inconclusive (evidence of bone healing is more easily detected at this time and is indicative of a recent fracture). Depending on the location and severity of these fractures, treatment can involve anything from use of a fracture (moon) boot with crutches, through to surgery to reattach the bone.

High Ankle Sprains

High Ankle Sprains are a more serious type of sprain that tends to involve a twisting movement of the lower leg (which may if the foot is caught on a rock while the body twists away from it) ^[4]. With this injury, pain tends to be felt higher above the ankle joint as the fibres the hold the two shins bones together are damaged. In addition to specific clinical tests, diagnosis of this injury usually includes a standing X-ray, and Diagnostic Ultrasound or MRI. Return to sport can occur in as little as two weeks for mild cases ^[4], though severe cases (where the shin bones have separated considerably), surgery is required to stabilise the leg and ankle.

Osteochondral Talar Dome Lesions

Osteochondral Talar Dome Lesions (TDL) involve damage to the cartilage and bone on the top of the talus bone (where the foot to the shin). There are several different grades of this injury depending on the severity of damage to the cartilage and bone. It is not well understood how these injuries develop, though chronically unstable ankles (i.e. those that do not regain sufficient ligament strength after a strain) are at a greater risk ^[1]. There is evidence that bone bruising is often present in the Talus after some ankle injuries which may lead to the develop of TDLs ^[5]. This bone bruising can be present for over 9 months ^[5].  Osteochondral TDLs may involve compression of the bone and cartilage, or have a chip of bone dislodge within the cartilage. Diagnosis is made via MRI or CT scans, and will usually involve a period of immobilisation (fracture boot), and to a year of recovery. In recurrent TDL injuries, or where the ankle is chronically unstable surgical reconstruction of the ankle joint may be necessary.

Early assessment is key

Runners can be their own worst enemies when it comes to stoically (or stupidly) ignoring injuries. Ankle sprains are an injury that deserves respect. Early assessment is essential to help guide you through the recovery and rehabilitation process while helping reduce the risk of it developing into a potentially more serious injury. If you’ve recently sprained your ankle, or have a recurrent history of this injury contact the intraining running injury clinic to discuss how best to manage your injury.

References

(1) Gregush, R. V., & Ferkel, R. D. (2010). Treatment of the Unstable Ankle with an Osteochondral Lesion: Results and Long-term Follow-up. The American Journal of Sports Medicine, 38(4), 782–790. https://doi.org/10.1177/0363546509351556 

(2) Kobayashi, T., & Gamada, K. (2014). Lateral Ankle Sprain and Chronic Ankle Instability: A Critical Review. Foot & Ankle Specialist, 7(4), 298–326. https://doi.org/10.1177/1938640014539813

(3) Mauntel, T. C., Wikstrom, E. A., Roos, K. G., Djoko, A., Dompier, T. P., & Kerr, Z. Y. (2017). The Epidemiology of High Ankle Sprains in National Collegiate Athletic Association Sports. The American Journal of Sports Medicine, 45(9), 2156–2163. https://doi.org/10.1177/0363546517701428 

(4) Miller, B. S., Downie, B. K., Johnson, P. D., Schmidt, P. W., Nordwall, S. J., Kijek, T. G., … Carpenter, J. E. (2012). Time to Return to Play After High Ankle Sprains in Collegiate Football Players: A Prediction Model. Sports Health, 4(6), 504–509. https://doi.org/10.1177/1941738111434916 

(5) Wang, X. (2017). The Significance of MRI in Process Change of Osteochondral Lesion of Talus. Foot & Ankle Orthopaedics. https://doi.org/10.1177/2473011417S000408