Ankle Sprains

WHAT IS AN ANKLE SPRAIN?

Ankle sprains are one of the most common musculoskeletal injuries in people of all ages with at least >300,000 injuries per year in the United States [Nelson et al, 2007].
The ankle joint comprises the talocrural joint (between the tibia, fibula, and talus) and the subtalar joint (between the talus and calcaneus). The ankle joint is surrounded by ligaments that help stabilize the joint.
The lateral ligaments stabilize the ankle against inversion forces where the foot rolls inward, while the deltoid ligament on the medial side resists eversion [Hertel, 2002; Safran et al, 1999].
An ankle sprain occurs when these ligaments are stretched beyond the normal range of motion. Most sprains involve the ligaments on the outside of the ankle and are minor, but in more severe cases the ligaments can be torn leading to joint instability.
The most common mechanism of injury is an inversion and plantarflexion force, leading to damage primarily to the lateral ankle ligaments, especially the anterior talofibular ligament (ATFL) [Kaminski et al, 2013].

HOW DO YOU GRADE ANKLE SPRAINS?

Grades: Ankle sprains are classified into three grades based on severity:
- Grade I: Mild sprain involve microscopic tears of the ligament fibers, minimal swelling, and no joint instability. The anterior talofibular ligament (ATFL) is most commonly affected.
- Grade II: Moderate sprain involve partial tearing of the ligament, moderate swelling, and some joint instability. Both the ATFL and the calcaneofibular ligament (CFL) are often involved.
- Grade III: Severe sprain involve complete rupture of the ligament, significant swelling, and marked joint instability. This grade involves a complete tear of the ligament, often affecting the ATFL, CFL, and sometimes the posterior talofibular ligament (PTFL). [Kaminski et al, 2013; How & Tan, 2014].

WHAT ARE THE SYMPTOMS OF AN ANKLE SPRAIN?

The symptoms of an ankle sprain vary depending on the grade of severity and the specific ligaments involved. Symptoms for acute ankle sprains include swelling and bruising around the ankle, pain, tenderness, decreased range of motion and difficulty walking.
Chronic ankle sprains are characterized by persistent symptoms and functional deficits following repeated injuries to the ankle ligaments and can result in chronic ankle instability. Up to 40% of individuals with an lateral ankle sprain develop symptoms of a chronic ankle sprain and instability [Hertel & Corbett, 2019; Herzog et al, 2019]. Repeated injuries and chronic instability can lead to degenerative changes in the ankle joint, with up to 78% of cases progressing to post-traumatic osteoarthritis [Owoeye et al, 2023; Wikstrom et al, 2013].
- Symptoms of chronic ankle sprain can include:
  - Persistent pain: Patients often report ongoing pain around the ankle joint, which can be exacerbated by physical activity [Alghadir et al, 2020; Hertel & Corbett, 2019].
  - Swelling: Chronic swelling may be present, particularly after prolonged activity or at the end of the day [Hertel & Corbett, 2019].
  - Instability: A common symptom is the sensation of the ankle "giving way" during activities, which can lead to recurrent sprains [Hertel & Corbett, 2019; Holmes & Delahunt, 2009].
  - Limited range of motion: Patients may experience stiffness and reduced flexibility in the ankle joint [Alghadir et al, 2020].
  - Weakness: There is often a noticeable weakness in the muscles surrounding the ankle, contributing to instability [Hertel & Corbett, 2019; Holmes & Delahunt, 2009].
  - Proprioceptive deficits: Impaired proprioception, or the ability to sense the position of the ankle, is frequently observed, leading to balance issues [Alghadir et al, 2020; Holmes & Delahunt, 2009].
- Functional impairments: Long-term deficits in balance, proprioception, and neuromuscular control can significantly impact daily activities and athletic performance [Alghadir et al, 2020; Holmes & Delahunt, 2009].

HOW IS AN ANKLE SPRAIN DIAGNOSED?

Diagnosis is based on detailed history, physical examination, and imaging. Certain physical tests may be utilized to reproduce symptoms and measure range of motion at time of exam.
What is the role of imaging in Acute Ankle Sprains?
- Radiographs (x-rays): Acute ankle sprains do not always need x-rays, but x-rays or plan radiographs can be used to rule out other condisions. The Ottawa Ankle Rules are used to determine the need for radiographs. Radiographs are indicated if there is bone tenderness at specific sites or an inability to bear weight [Kaminski et al, 2013; Smith et al, 2020].
- Diagnostic ultrasound: Can be helpful in assessing acute ankle sprains, including grading the severity of the sprain and predicting recovery outcomes. Ultrasound is highly effective in diagnosing ligament injuries, particularly the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). It provides real-time, dynamic imaging, which is beneficial for evaluating the extent of ligament damage and differentiating between partial and complete tearsx
  - Studies have shown that ultrasound has high sensitivity and specificity for detecting ATFL injuries, with values reaching up to 100% for both parameters. [Hosseinian et al, 2022; Baltes et al, 2021].
    - For instance, it can distinguish between Grade I (mild sprain with microscopic tears), Grade II (moderate sprain with partial tears), and Grade III (severe sprain with complete tears) injuries. This grading is crucial for determining the appropriate management and rehabilitation strategies [George et al, 2020; Kemmochi et al, 2016].
  - The severity of the injury as assessed by ultrasound is a prognostic factor for long-term outcomes. The number of completely torn ligaments, as identified by ultrasound, significantly affects functional outcomes, including pain and daily living activities. Therefore, ultrasound findings can help predict recovery trajectories and guide treatment plans [Choi et al, 2020].
What is the role of imaging in Chronic Ankle Sprains?
- Magnetic Resonance Imaging (MRI): MRI is recommended typically in patients with acute ankle sprains that do not resolve and result in chronic ankle instability. Chronic ankle instability occurs from recurrent sprains and patients report persistent pain and a sensation of the ankle "giving way" [Kaminski et al, 2013; Smith et al, 2020].
- Diagnostic ultrasound: Ultrasound is highly effective in diagnosing chronic ankle sprians and chronic ankle instability with studies demonstrating that ultrasound has high sensitivity and specificity for detecting chronic ligament injuries.
  - One study by Cheng et al. demonstrated that ultrasound had a sensitivity of 98.9% and specificity of 96.2% for ATFL injuries, and 93.8% sensitivity and 90.9% specificity for CFL injuries when compared to operative findings [Cheng et al, 2014].
  - Another study by Lee and Yun showed that ultrasound is as precise as MRI for detecting major ankle ligament injuries, with excellent inter-observer reliability [Lee & Yun, 2017].
  - George et al. found a 100% specificity in ultrasound detecting complete (Grade III) ATFL and CFL tears, making it a reliable tool for assessing the extent of
    ligamentous injury [George et al, 2020].

TREATMENT

Conservative Management

Initial treatment of acute ankle sprains consists of immediate care (rest, ice, NSAIDs, bracing) and physical therapy for functional rehabilitation [Kaminski et al, 2013].

Platelet Rich Plasma (PRP) Injections

PRP concentrates a patient’s blood to increase various growth factors. The outcomes of platelet-rich plasma (PRP) injections for treating ankle sprains have been evaluated in several studies. PRP injections may offer short-term benefits in pain reduction and functional improvement with faster return to sport for acute ankle sprains, but results regarding their efficacy have been mixed.
- A study by Zhang et al. investigated the use of PRP injections in patients with Grade II lateral ankle sprains. The study found that PRP injections, particularly when administered twice (once within 48 hours and again 4 weeks later), resulted in better short-term pain reduction and functional outcomes compared to no PRP treatment [Zhang et al, 2022].
- Laver et al. conducted a randomized controlled trial on elite athletes with high ankle sprains (syndesmotic injuries). The study demonstrated that PRP injections led to a significantly shorter return to play (RTP) time and less residual pain compared to the
  control group. The PRP group had an average RTP of 40.8 days versus 59.6 days in the control group, with fewer patients experiencing residual discomfort [Laver et al, 2015].
- Rowden et al. performed a double-blind, randomized, placebo-controlled study on acute ankle sprains in an emergency department setting. This study found no significant difference in pain control or functional outcomes between the PRP and placebo groups, but the study only followed patients for 30 days [Rowden et al, 2015].

Surgical Intervention

Surgical options for treating ankle sprains primarily focus on addressing chronic lateral ankle instability, which can develop following acute ankle sprains that do not heal properly. Surgery may be necessary for more complex cases or chronic instability to reconstruct the injured ligament(s).

REFERENCES:

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Baltes TPA, Arnáiz J, Geertsema L, Geertsema C, D'Hooghe P, Kerkhoffs GMMJ, Tol JL. Diagnostic value of ultrasonography in acute lateral and syndesmotic ligamentous ankle injuries. Eur Radiol. 2021 Apr;31(4):2610-2620.

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