Ankle Sprain

<中文版>

Ankle sprain describes injury of the ankle joint resulted in unexpected excessive ankle and foot movements.

Definition:

Ankle sprain describes injury of the ankle joint resulted in unexpected excessive ankle and foot movements. It is the most common sports injury among athletes. It is estimated that there are 2 millions injuries per year. 85 percent of sprains are inversion injuries and lateral ligaments are injured. Occasionally, medial ligaments are involved. Bony injury is not common but has to be considered if there is bony tenderness.

Broadly speaking, there are two broad categories of ankle sprain:

• Inversion Ankle Sprains
  This is the more common type of ankle sprain that occurs when the foot is inverted, turning inward. When this type of ankle sprain happens, the outer, or lateral, ligaments are over-stretched beyond their anatomical limits and therefore get injured. About 90% of ankle sprains are inversion injuries. As there are three ligaments that attach to the outer side of the ankle, most of the signs and symptoms are on the outside of the ankle.
• Eversion Ankle Sprains
  The other type of sprained ankle is eversion injury, where the foot is twisted outwards. When this occurs, the inner, or medial, ligament, called the deltoid ligament, is over-stretched and gets injured. Patients will have signs and symptoms on the inner side of the ankle.

Symptoms and signs:

Patient often presents soon after injury. Patient may have pain and difficulty in walking. There may be local redness, bruising, and swelling. It is not uncommon that patient seeks treatment from bonesetters and presents to doctor with allergic contact dermatitis. Sometimes patient presents with unexplained ankle pain and give a history of pervious ankle injury.

Examination shows localized swelling, bruising and tenderness over the injured ligament usually at the lateral side. There may be tenderness over ankle joint line and involved ligaments. When there is bony tenderness, fracture has to be excluded. Ligament stress tests such as anterior drawer test, talar tilt test, will reproduce pain and shows signs of laxity.

Cause and biomechanics considerations:

Athletes often sustained ankle injury during competition or training. The causes may be internal or external. Internal causes are biomechanical causes from within the body such as laxity of ankle ligaments left over from previous ankle injuries, faulty biomechanics from foot arch problems or from weak peroneus muscles (a group of lateral leg muscles which protect for ankle from excessive pronation or inversion during the gait cycle). External factors include improper shoes or playing on slippery or uneven surfaces. Women may sprain their ankles while wearing high heel shoes. Some may miss a step. Musculoskeletal physicians will examine ankles, feet and even shoes, watch patient’s gait, and identify patient’s stance axis. The aim is to identify any biomechanical factors such as varus neutral stance axis, peroneal muscle weakness, or injured interosseous ligament, which may contribute to unstable ankle joint.

Clinical Stages:

Ligament injury is graded according to the severity. The following is the West Point Sprain Grading System

Investigations:

To rule out co-existing bone fractures, the Ottawa foot rule states that X-ray of the foot should be considered in the following conditions

• Navicular bone tenderness
• Base of fifth metatarsal tenderness
• Inability to bear weight immediately following the injury and during examination 

and the Ottawa Ankle Rule states that X-ray of the ankle should be considered when there is 

• Posterior edge (6cm) or tip of lateral malleolus tenderness
• Posterior edge (6cm) or tip of medial malleolus tenderness
• Inability to bear weight immediately following the injury and during examination

Musculoskeletal ultrasound can show the ligament or tendon tears, the associated synovitis and effusion. MRI shall be considered to confirm talar dome or cartilaginous injury.

Treatment:

Treatment depends on the presentation and severity of the injury. The aim is to control swelling and pain during acute stage; strengthen leg muscles, improve balance and return to normal daily activities or usual sports. At acute stage, the treatment plan follows the usual PRICE (Protect, Raise, Ice, Compression and Elevation). When acute pain is under control, patient shall undergo rehabilitation exercise to regain range of motion, muscle power, balance, and sport specific performance. If the ankle sprain is recurrent, biomechanical problems should be identified and rectified. When the injury occurred some time ago and there are chronic joint or ligament injuries, the treatment of choice is prolotherapy.

踝關節扭傷

"踝關節扭傷"指的是，腳踝和足部因過度運動而導致踝關節意外受傷，是最常見的運動創傷。

定義:

"踝關節扭傷"指的是，腳踝和足部因過度運動而導致踝關節意外受傷，是最常見的運動創傷。據估計，每年大約有200萬個踝關節扭傷的案例，其中85% 屬於內翻扭傷，引致外側韌帶受傷；內側韌帶偶爾也會受到影響。骨損傷並不常見，但如果出現骨壓痛，便要考慮骨折的可能性。

廣義而言，踝關節扭傷可以分為兩大類：

• 內翻腳踝扭傷（Inversion Ankle Sprains）
  這是比較常見的踝關節扭傷，通常是足部向內屈時發生的。當足部內翻時，外側的韌帶就會過度拉緊，當它伸展的力度超過了結構上所能承受的範圍時就會導致受傷。大約90% 的踝關節扭傷是屬于內翻扭傷的。扭傷表徵及症狀都是出現在腳踝外部的。
• 外翻腳踝扭傷（Eversion Ankle Sprains）
  另外一種的踝關節扭傷是"外翻扭傷"，是足部向外旋轉時發生的。當足部外翻時，內側的韌帶，稱為"三角韌帶"，或"內側副韌帶"，由于伸展過度而受傷。表征及症狀會出現在腳踝內側。

症狀與表徵:

病人通常在受傷之後沒多久就前來求醫。病人可能會覺得疼痛，而且走路有困難；可能會有局部的紅腫及瘀傷。另外一個常見的情況是病人之前看過跌打師傅，前來求醫時足部出現過敏性接觸性皮炎。有時候可能會遇到一些病人出現原因不明的踝關節疼痛，而病人有過踝關節損傷的病史。

體檢結果顯示，受傷的韌帶（通常在外側）周圍出現局部性腫脹、瘀傷及壓痛；在踝關節線及受傷的韌帶周圍可能會出現壓痛。如果出現骨壓痛，必須進一步檢查以排除骨折的可能性。進行韌帶壓力測試時，例如向前曳引檢查、距骨傾斜檢查，會產生痛楚並有鬆弛的跡象。

原因及與生物力學的關係:

運動員在比賽或訓練時往往要承受踝關節扭傷帶來的傷害。扭傷的原因可以是內在的或外在的因素。內在的因素，一般是與身體結構本身、及生物力學有關的，例如因過往發生過踝關節扭傷而使踝關節韌帶變得鬆弛；或者因足弓問題或較弱的腓骨肌帶來生物力學上的問題。扭傷的外在因素包括穿著不合適的鞋子、在濕滑或不平坦的地面上玩耍。女士可能會因為穿高跟鞋走路而扭傷；某些病人則可能因為失足而受傷。肌骼科醫生會檢查病人的腳踝、足部，甚至鞋子，觀察病人走路的步態，並找出病人的站立軸。檢查的目的是鑒定病人不穩定的踝關節是否與任何的生物力學上的因素有關，例如內翻的中性站立軸、無力的腓骨肌，或者受傷的骨間韌帶。

臨床階段:

韌帶受傷是根據症狀的嚴重程度來分級的，以下是"西點踝關節扭傷分級制度（West Point Sprain Grading System）"的分級

檢驗:

為了排除骨折的可能性，"渥太華足部損傷鑒別診斷標準（Ottawa Foot Rule）"指出，在以下情況下應考慮照足部X光：

• 舟狀骨出現壓痛
• 第五蹠骨基底出現壓痛
• 扭傷之後就立即感到難以承受體重，接受檢查時承受體重也有困難

同時，"渥太華腳踝損傷鑒別診斷標準（Ottawa Ankle Rule）"亦指出，在以下情況下應考慮照踝部X光：

• 外踝後緣（6厘米）或外踝尖出現壓痛
• 內踝後緣（6厘米）或內踝尖出現壓痛
• 扭傷之後就立即感到難以承受體重，接受檢查時承受體重也有困難

肌骼超音波可以顯示出韌帶或肌腱撕裂、相關的滑膜炎以及積水的情況。另外，可以考慮利用磁力共振掃描來確定距骨背或軟骨是否受傷。

治療:

治療方案要視乎扭傷的症狀及嚴重性。治療的目的主要是控制急性期間的腫脹和疼痛情況、加強腿部肌肉、改善平衡力，並恢復日常的活動或運動。在急性期間，治療計劃主要是遵循PRICE的處理原則：保護（Protection）、休息（Rest）、冰敷（Ice）、壓迫 (Compression），及抬高（Elevation）。急性疼痛得到控制之後，病人應開始接受康復治療，以恢復關節活動度、肌力、平衡力以及運動技能。如果踝關節扭傷是經常性發生的，就應該找出生物力學上的問題，繼而作出矯正。如果扭傷引至慢性疼痛、或出現慢性關節或慢性韌帶受傷，則應採取保絡治療（Prolotherapy）。