Tennis Elbow

<中文版>

Tennis elbow is also known as lateral epicondylitis. It is a condition where the outer part of the elbow becomes sore and tender.

Definition:

Tennis elbow is also known as lateral epicondylitis. It is a condition where the outer part of the elbow becomes sore and tender. It is commonly associated with playing tennis and other racquet sports, and hence the term tennis elbow. The injury can actually happen to almost anybody whose works or daily activities requiring repetitive wrist dorsiflexion with supinations and pronations.

Symptoms and signs:

Tennis elbow is one of the most common overuse syndromes seen in primary care. The condition occurs primarily in patients between age 30 and 50 and it affects men and women equally. The pain is typically located at elbow around the lateral epicondyle of the humerus bone. Occasionally, patients may complain of pain over the wrist extensor muscle mass just distal to the lateral epicondyle. In physical examination, there should be point tenderness over the origin of the common wrist extensor muscles at the lateral epicondyle, particularly over the origin of the extensor carpi radialis brevis (ERCB). In addition, there should be pain with passive wrist flexion and also with resisted wrist extension, both tested with the elbow extended.

Cause and biomechanics considerations:

Tennis elbow is commonly attributed to repetitive wrist dorsiflexion with supinations and pronations. This causes overuse of the forearm extensor tendons and subsequent micro-tears at the musculotendinous junction with collagen degeneration, and angiofibroblastic proliferation. Most often the origin of the ECRB displays an abnormal vascular proliferation and focal hyaline degeneration.

The radial collateral ligament attaches proximally to a tubercle on the lateral epicondyle and distally by fanning out onto the annular ligament and radial head, in the form of a triangle. Recent biomechanical studies showed that activities causing repeated micro-trauma and subsequent laxity of these 2 ligaments might precede the development of tennis elbow.

The posterior interosseous nerve (PIN) branches out from the radial nerve and supplies the ERCB and supinator muscle before entering into the supinator muscle itself at the arcade of Frohse. The PIN can sometimes be compressed at the arcade of Frohse by its musculotendinous fibers causing symptoms similar to tennis elbow. This PIN entrapment syndrome should be considered in all tennis elbow patients that are resistant to treatments. Unlike tennis elbow patients, patients with PIN entrapment syndrome have weakness or paralysis of the digital extensors.

Investigations:

The diagnosis is almost always clinical. X-rays are not helpful unless other differential diagnosis is suspected, e.g. a C5-6 cervical radiculopathy. If needed, degenerative tendinosis and muscle tears of the common wrist extensor muscles can sometimes be seen on musculoskeletal ultrasound or MRI imaging.

Treatment:

Treatment depends on severity of symptoms as well as the patient’s daily and recreational activities. For a sports player, resting is the treatment of choice as soon as the pain first appears because the resting allows the micro-tears in the tendon attachment to heal. Other treatment options can include a combination of the followings:

• Non-steroidal anti-inflammatory analgesics (NSAIDS)
  Topical NSAIDs may provide short-term pain relief, but long-term outcomes were not reported. On the other hand, evidence is conflicting on the use of oral NSAIDs for tennis elbow.
• Local corticosteroid injection
  It can provide short-term (2 to 6 weeks) benefits in pain reduction, global improvement, and grip strength compared with other conservative treatments. However, these benefits do not persist beyond 6 weeks¹.
• Orthoses
  Despite its widespread use, multiple well-designed studies have been unable to provide conclusions about the benefits of orthosis for tennis elbow.
• Topical nitrates
  A study has demonstrated that topical nitroglycerin patch reduced elbow pain with activity at 2 weeks, reduced epicondylar tenderness at 6 and 12 weeks, and increased wrist extensor mean peak force and total work at 24 weeks. At six months, 81% patients were asymptomatic during activities of daily living².
• Corrective actions 
  To prevent recurrence of the condition, musculoskeletal physicians will look into the causative ergonomic or environmental factors and give appropriate advice on modification.
• Surgery
  Surgery may be indicated when conservative strategies fail to relieve symptoms after 6 to 12 months. There are numerous surgical approaches including open and arthroscopic techniques. Most surgical procedures excise the abnormal tissue within the origin of the ERCB tendon at the lateral epicondyle or release the tendon altogether.
• Prolotherapy
  For tennis elbow that are resistant to conservative treatment and after PIN entrapment syndrome has been ruled out, musculoskeletal physicians may recommend prolotherapy to trigger the body’s own tissue response to repair the injured tendons. This is particular useful to patients as an alternative to surgery³.

References:

1. Assendelft W, Green S, Buchbinder R, Struijs P, Smidt N. Tennis elbow. Clin Evid 2004;(11):1633-44
2. Paoloni JA, Appleyard RC, Nelson J, Murrell GA. Topical nitric oxide application in the treatment of chronic extensor tendinosis at the elbow: a randomized, double-blinded, placebo-controlled clinical trial.Am J Sports Med 2003;31:915-20
3. Scarpone M, Rabago DP, Zgierska A, Arbogast G, Snell E. The efficacy of prolotherapy for lateral epicondylosis: a pilot study. Clin J Sport Med. 2008 May;18(3):248-54.

網球肘

網球肘，正式名稱為"肱骨外上髁炎"(lateral epicondylitis)，是一種會引起手肘外側疼痛及壓痛感的炎症。

定義:

網球肘，正式名稱為"肱骨外上髁炎"(lateral epicondylitis)，是一種會引起手肘外側疼痛及壓痛感的炎症。因為這是網球及其他球拍運動很常見的運動傷害，所以俗稱為"網球肘"。但其實幾乎任何人都有可能患上網球肘，只要他們的工作或日常生活中經常需要手腕做出旋後及旋前的屈背動作。

症狀與表徵:

網球肘是基層醫療中常見的過度使用症之一。此症多發於 30 至 50 歲之人士，而男女的發病率均等。痛症一般出現在肱骨外側上髁 (lateral epicondyle) 的手肘位置；有時，病人可能會表示手肘外側上髁末端的腕伸肌總腱也會疼痛。進行身體檢查的時候，外側上髁的腕伸肌源頭應該會出現點壓痛，特別是在橈側腕短伸肌（Extensor carpi radialis brevis, ERCB）起端的周圍。除此之外，在伸展的手肘下，手腕的被動屈曲及抗力伸展會產生痛楚。

病因及與生物力學的關係:

網球肘通常是因為手腕反覆用力做出旋後及旋前的屈背動作而引起的。這些動作會導致前臂伸肌的肌腱過度使用，在肌肉肌腱的連接處出現微小破裂，引致膠原蛋白產生退化(collagen degeneration)，血管纖維母細胞增生(angiofibroblastic proliferation)。這異常的血管增生及局部的玻璃樣質變 (hyaline degeneration)多見於橈側腕短伸肌的起端。

橈側副韌帶 (radial collateral ligament) 的近端緊附著肱骨外側上髁的結節，末端以扇形散開與橈骨頭部的環狀韌帶交織在一起，呈一三角形。近期的生物力學研究發現，這兩條韌帶可因反覆性動作而受到微創傷，變得鬆弛，最終發展成網球肘。

後側骨間神經 (posterior interosseous nerve, PIN) 是從橈神經分支出來的，在供應神經給予橈側腕短伸肌 (ERCB) 和旋後肌 (supinator muscle) 後，再穿過旋後肌腱弓(arcade of Frohse，亦稱為"佛羅氏弓") 而進入旋後肌。後側骨間神經可能在佛羅氏弓內受到旋後肌的肌腱纖維擠壓，而產生類似網球肘的症狀。因此，對治療反應不佳的網球肘病患者，醫生應該考慮他們是否患上後側骨間神經卡壓症 (PIN entrapment syndrome)。和網球肘病患者不同的是，後側骨間神經卡壓症的患者的指伸肌會較弱或癱瘓。

檢驗:

網球肘的診斷通常都是臨床的。除非懷疑有其他的鑑別診斷，例如第5節和第6節頸神經根病變 (C5-6 cervical radiculopathy)，X光掃描的作用不大。如有需要，肌骼超聲波或磁力共振掃描可顯示出腕伸肌的肌腱退化及肌肉撕裂情況。

治療:

治療方案主要視乎症狀的嚴重程度以及病人的日常生活和消閒活動。如果是運動員，休息是痛症一出現時最好的治療方法，因為休息可以讓出現細微撕裂的肌腱慢慢癒合。另外可以配合以下其中一項治療方法：

• 非類固醇類消炎劑 (NSAIDs)
  局部外用的非類固醇類消炎劑可能可以短暫舒緩痛楚，但並沒有報告指其具有長期療效。另外，以口服 NSAIDs 來治療網球肘，科研證據是矛盾的。
• 皮質類固醇局部注射 (Local corticosteroid injection)
  與其他保守的療法相比較，皮質類固醇局部注射可以在減輕痛症、整體改善及握力方面帶來 2 至 6 週的短期療效；但療效一般不能持續超過 6 週¹。
• 護具 (Orthoses)
  雖然肘部護具已被廣泛使用，也有多項設計完善的科研項目調查過護具對網球肘的療效，但到目前為止，對於護具對網球肘的好處還是未有結論。
• 局部外用的硝酸鹽 (Topical nitrates)
  一項研究結果顯示，在使用局部外用的硝酸甘油貼片 2 週後，可以有效減輕手肘活動時的痛症；6 週及 12 週後，可以舒緩上髁的壓痛感；24 週後，可以增加腕伸肌的平均峰力值（mean peak force）及手腕的總工作量；6個月後，81% 的病人可以無症狀地進行日常生活的活動²。
• 預防性的矯正措施 (Corrective actions) 
  為了防止網球肘重複發作，肌骼科醫生會檢查致病的生物力學或環境因素，然後就改變方面給予適當的意見。
• 外科手術 (Surgery)
  如果接受了 6 至 12 個月的保守療法後仍未能舒緩症狀，可能需要外科手術幫助。手術方法也有幾種，包括切開 (open technique) 和內窺鏡(arthroscopic technique) 手術。大多數的外科手術會切除位於肱骨外側上髁的橈側腕短伸肌起端周圍的異常組織，或同時釋放緊縮的肌腱。
• 保絡治療 (Prolotherapy)
  對保守療法失效、而又排除了後側骨間神經卡壓症的網球肘病患者，肌骼科醫生可以建議他們接受保絡治療。保絡治療可以刺激人體組織作出反應，對受傷的肌腱自行修補。保絡治療是手術以外一個很有效的治療選擇³。

參考文獻:

1. Assendelft W, Green S, Buchbinder R, Struijs P, Smidt N. Tennis elbow. Clin Evid 2004;(11):1633-44
2. Paoloni JA, Appleyard RC, Nelson J, Murrell GA. Topical nitric oxide application in the treatment of chronic extensor tendinosis at the elbow: a randomized, double-blinded, placebo-controlled clinical trial.Am J Sports Med 2003;31:915-20
3. Scarpone M, Rabago DP, Zgierska A, Arbogast G, Snell E. The efficacy of prolotherapy for lateral epicondylosis: a pilot study. Clin J Sport Med. 2008 May;18(3):248-54.