Tennis elbow is also known as lateral epicondylitis. It is a condition where the outer part of the elbow becomes sore and tender.
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.
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 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:
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。
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。
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。
Date: 26 July 2020 (Sun)
Venue: virtual meeting