Cumulative Trauma Disorder

Cumulative trauma disorder is injury to tendons, muscles, nerves and joints from repeated microtrauma that outpaces recovery, caused by repetition, force, awkward posture, contact stress, vibration and cold at work. Symptoms develop gradually over weeks to years.

Tissue involvement. Tendinopathy and tenosynovitis, bursitis, entrapment neuropathy, muscle myalgia and joint strain. Upper limb and neck are the commonest sites.

Epidemiology. Common in assembly, packing, meat processing, keyboard and checkout work, construction and healthcare. Prevalence rises with repetitive force and short cycle times.

Staging. Stage 1: aching and fatigue during work that settle overnight. Stage 2: symptoms start earlier, persist overnight and reduce work capacity. Stage 3: symptoms at rest, disturbed sleep and difficulty with light tasks.

Individual factors. Female sex, age over 40, diabetes, obesity, hypothyroidism, rheumatoid disease and pregnancy.

Pathophysiology.

Microtears accumulate in tendons and muscle when load exceeds repair. Degenerative change, local ischaemia and mechanical compression of nerves follow.

Prolonged exposure leads to peripheral and central sensitisation and chronic pain.

• Localised pain, stiffness, swelling and weakness related to work tasks.
• Numbness and tingling in nerve distributions, often worse at night.
• Reduced grip strength and dexterity in advanced stages.

Red flags.

• Constant pain, fever, weight loss or hot joints.
• Progressive weakness, wasting or fixed sensory loss.
• Symptoms in several limbs with systemic features, or after trauma.

• Job analysis: cycle time, force, posture, tools, vibration, breaks and recent change.
• Examination by region: palpation, provocative tests, neurological testing and range of movement.
• Ultrasound or MRI for tendon or soft tissue lesions.
• Nerve conduction studies for neuropathic symptoms.
• Blood tests for diabetes, thyroid disease and inflammatory arthritis when indicated.

Differential diagnosis. Inflammatory arthritis, osteoarthritis, cervical radiculopathy, thoracic outlet syndrome, hypothyroid myopathy, diabetic neuropathy, fibromyalgia, gout and vascular disease.

• Redesign the task: reduce force and repetition, improve posture, rotate tasks, schedule breaks and supply suitable tools.
• Physiotherapy with strengthening and stretching; temporary splints for specific lesions; graded return to full duties.
• Paracetamol 1 g orally every 6 hours as needed, maximum 4 g in 24 hours (3 g if under 50 kg, chronic alcohol excess or liver disease), for the shortest period that controls pain. Monitor liver function with prolonged use. Reduce dose in hepatic impairment; extend dosing interval when eGFR is under 30.
• Ibuprofen 400 mg orally three times daily with food for up to 7 days, maximum 2400 mg daily. Monitor blood pressure, renal function and gastrointestinal symptoms. Avoid if eGFR is under 30, in active peptic ulcer, heart failure or the third trimester; add gastroprotection in older adults or those at risk.
• Diclofenac 1% gel applied topically, 2 g to the affected upper limb joint four times daily, for up to 3 weeks. Maximum 8 g daily to any one upper limb joint and 32 g daily in total. Monitor skin reaction and renal function with prolonged use. Avoid on broken skin, in aspirin sensitive asthma and in the third trimester; avoid when eGFR is under 30.
• Stage 3 disease or entrapment with motor loss: specialist review for injection or surgery.

Monitoring. Review at 4 to 6 weeks and every 3 months; staging at each visit.

Referral and escalation. Occupational physician; orthopaedic, hand surgery or rheumatology review for refractory or atypical disease; notification and compensation where required.

Special groups. Pregnancy: paracetamol and splinting are preferred. Older adults: limit NSAID duration and add gastroprotection.