Many occupations involve repetitive movements, which can cause injuries such as tendinitis, bursitis, and nerve entrapment syndromes. Symptoms include pain worsening with movement and sometimes tenderness. Diagnosis is clinical. Treatment involves rest, sometimes involving a splint, NSAIDs (nonsteroidal anti-inflammatory drugs), and physical therapy.
Repetitive motion injuries account for many work-related injuries. Tasks that require repetitive movements or postures include typing at a computer, scanning groceries, hammering nails, working on an assembly line, and using a jackhammer.
Tendinitis is tendon inflammation caused by repeated overloading of a muscle, which results in microtears in the tendon. The body spontaneously repairs microtears, but when the formation of microtears outpaces the body’s ability to repair them, inflammation occurs and causes tendonitis. Work-related tendonitis commonly develops in the biceps, elbow, and rotator cuff (see table Common Work-Related Tendonitides).
Bursitis is inflammation of a bursa sac caused by repeated pressure on a joint surface. When not inflamed, bursae provide a low friction surface that enables muscle or tendon to smoothly slide over bone during joint movement. When a bursa becomes inflamed, synovial fluid accumulates in it, and it becomes painful. Work-related bursitis commonly affects the elbow, shoulder, hip joint, and knee (see table Common Work-Related Bursitides).
Nerve entrapment results from compression of a peripheral nerve as it travels through an anatomic tunnel. As a result, the nerve malfunctions; sensory abnormalities are more common than motor weakness. Work-related nerve entrapment commonly occurs in the wrist and elbow (see table Common Work-Related Nerve Entrapment Syndromes).
Symptoms and Signs
Tendonitis usually causes pain when the affected tendons are actively moved, particularly against resistance. The affected tendon is tender when palpated. In severe cases, warmth, edema, and erythema may be present, but skin induration is absent.
Bursitis results in pain and particularly tenderness that localizes to the affected bursa. Active or passive joint movement worsens pain as a muscle or tendon slides over the inflamed bursa. Synovial fluid accumulates in the bursa, causing it to swell (although swelling is not always evident grossly); the bursa is tender and the skin covering it may be warm or red, Movement that compresses or stretches the swollen bursa also causes pain. Swelling may be more prominent than pain in olecranon bursitis.
Nerve entrapment most commonly causes pain, tingling, numbness, and burning distal to the site of entrapment. Motor weakness is less common.
Diagnosis
Clinical evaluation
Sometimes nerve conduction studies or MRI
Diagnosis of repetitive motion injury is primarily clinical based on the location of the pain and the movement that elicits pain; however, diagnostic testing is sometimes indicated. An occupational history is important to identify the nature of the repetitive motion that is causing the patient’s symptoms.
Tendinitis is suspected when active movement of a tendon (particularly against resistance) causes pain. Tenderness when the tendon is palpated supports the diagnosis of tendinitis. Physicians can distinguish some severe cases of cellulitis from tendinitis if skin induration is present; such induration, sometimes present in cellulitis, is absent in tendinitis.
Common Work-Related Tendonitides
Site of Tendinitis | Movement That Elicits Pain* | Site of Tenderness During Palpation |
|---|---|---|
Biceps | Flexion at elbow with forearm supinated | Anterior aspect of shoulder |
Medial epicondyle (golfer’s elbow) | Wrist flexion and forearm pronation | At and just distal to medial epicondyle of the humerus |
Lateral epicondyle (tennis elbow) | Wrist extension | At and just distal to lateral epicondyle of the humerus |
Shoulder abduction between 60–120° | None | |
*When resistance is applied. | ||
Bursitis is suspected when swelling or signs of inflammation over bursae are present or when patients have unexplained pain that is worsened by movements affecting bursae. Bursitis due to repetitive motions should be distinguished from infectious (septic) bursitis, which requires antibiotic therapy, and crystal-induced bursitis (eg, gout), which may require other specific treatments. When infectious or crystal-induced bursitis is suspected, synovial fluid should be aspirated and sent for laboratory analysis.
Common Work-Related Bursitides
Affected Bursa | Location of Bursa | Causative Repetitive Movement |
|---|---|---|
Ischial | Between the ischial tuberosity and gluteus maximus | Prolonged sitting on hard surface |
Olecranon | Posterior to the proximal tip of the ulna | Resting point of elbow on hard surface |
Prepatellar | Anterior (superficial) to the patella | Kneeling |
Subacromial | Between the most lateral part of the supraspinatus tendon and the acromion | Overhead arm movement |
Nerve entrapment syndromes are typically clinical, suspected when a worker presents with abnormal sensations along the territory of certain nerves. In some cases, nerve conduction studies may be useful in confirming the diagnosis but are not routinely required. Imaging is not typically done, but MRI may be done when a structural cause (eg, tumor) is suspected.
Common Work-Related Nerve Entrapment Syndromes
Syndrome | Nerve (location) | Area of numbness | Causative Repetitive Movement |
|---|---|---|---|
Median (wrist) | Lateral hand; thumb, index, and middle fingers and lateral half of the ring finger | Wrist extension and flexion, vibration | |
Ulnar (elbow) | Medial hand, little finger, medial ring finger | Elbow flexion or leaning on the elbow |
Prognosis
Most work-related repetitive motion injuries resolve with rest over a period of weeks. However, nerve entrapment syndromes may persist, resulting in chronic pain.
Treatment
Rest
Analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy
For tendinitis, corticosteroid injection
For bursitis, drainage
For nerve entrapment, a splint or brace and possibly corticosteroid injections or surgery
Treatment of work-related repetitive motion injury includes resting the affected area. Workers may need to be placed on transitional duty (also known as light duty or modified duty) if their normal job duties cannot be done without the repetitive motion that caused the injury. Depending on the type and severity of the injury, transitional duty may last for weeks to months. If job duties that include the repetitive motion are resumed too early, the injury may recur, resulting in return to transitional duty and ultimately increasing the time spent in transitional duty. Workers should be instructed to avoid home activities that exacerbate their injury.
Medical therapy for work-related repetitive motion injury includes analgesics and anti-inflammatory drugs. NSAIDs are typically effective for short-term relief of pain caused by repetitive motion injuries, and they speed resolution of tendinitis and bursitis.
Physical therapy may benefit workers with repetitive motion injuries and may speed recovery.
For tendinitis, injection of a corticosteroid over the affected tendon relieves pain in the short term; however, corticosteroids are not necessarily effective long term and may have adverse effects such as scarring, tendon weakening, and tendon rupture.
For bursitis, with gross swelling or that may be infected, drainage of fluid in the affected bursa, with or without injection of a corticosteroid, relieves pain and may speed recovery. After drainage, a compressive dressing (eg, elastic bandage) may reduce the reaccumulation of fluid.
For nerve entrapment syndromes, use of a splint or brace may relieve symptoms. If symptoms are severe or persist, referral to an orthopedic surgeon for corticosteroid injections and possible surgical intervention may be necessary.
Key Points
Because many jobs involve repetitive motion, work-related repetitive motion injuries are common.
Distinguish repetitive motion bursitis from infectious bursitis, which requires antibiotics.
Treat all work-related repetitive motion injuries as needed with analgesics, anti-inflammatory drugs, and physical therapy; tendinitis with corticosteroid injections; and bursitis with drainage with or without a corticosteroid injection.
For nerve entrapment syndromes, try a splint or a brace, but for severe or persistent symptoms, refer to an orthopedic surgeon for possible corticosteroid injections and/or surgical intervention.
