Repetitive Motion Injuries

tendon and sheath disorders

• Most Common RMI

Slow onset and innocuous

• characteristic of microtrauma

• Ignored until symptoms are chronic and injury is permanent

stage 1 RMI

• Aches and tiredness during working hours

• Settle overnight and over days off work

• No reduction in work performance

• Persist for weeks or month

• Reversible

stage 2 RMI

• Symptoms start early in the work shift

• Do not settle overnight; disturbs sleep

• Capacity to perform repetitive work is reduced

• Persists over months

stage 3 RMI

• Symptoms persist at rest

• Pain occurs with non-repetitive movements

• Disturbed sleep

• Unable to perform even light duties

• Experiences difficulties in other tasks

• Persists over months or years

Tendinitis

• Inflammation and thickening of tendon d/t repeated and forceful movements

• Thickening tendon eventually lock and render movement useless

• Occurs at the site of insertion into bone

Bursitis

• Inflammation of the bursa

  • Fluid-filled fibrous sac found in areas subject to friction

  • Around joints or where tendon passes bone

• Excessive, prolonged, repeated pressure or jolts lead to inflammation, with symptoms of severe pain and restricted movements

Tenosynovitis

• Wrist tendons are enclosed in synovial sheaths

• Double-walled sleeve of sheath secretes synovial fluid, providing lubrication for tendon to avoid rubbing, friction, and pressure

• Rest periods are needed to replenish fluid

• Irritation of the boundary between the tendon and surrounding sheath

Carpal Tunnel Syndrome

• Most common UE nerve entrapment

• Flexing the wrist causes tendons inside the carpal tunnel to compress on median nerve

• Swelling or thickening of tendons inside carpal canal leads to pressure on medial nerve

• Numbness, tingling pain, and weakness

Electromyogram

• Diagnosis of CTS

• Needle electrode inserted directly into a muscle records electrical activity in muscle

Nerve Conduction Study

• Diagnosis of CTS

• Surface electrodes measure speed and strength of signals travelling between two or more points

Splinting for CTS

• Inactivity wrist splint 3-4 weeks, followed by night wear 3-4 weeks

• Can weaken muscle, decrease ROM

• If there are jobs that require major movements of splinted area, it may be more stressful with a splint

Phonophoresis

• Ultrasound to enhance delivery of topically applied drugs

• Enhance absorption by increasing cell permeability

Ionophoresis

• Transdermal drug delivery by use of voltage gradient on skin

• Dexamethasone for inflammation

• Cryotherapy

Tendon and Nerve Glides for CTS

• Relieve pressure on median nerve and stretch carpal ligaments

• Help blood flow out of the carpal tunnel

• Hold each position for 7s/10reps/3-5x per day

Cervical Radiculopathy or Pinched Nerve

• Compression of disks in the neck that can occur from osteophyte formation, disc herniation, or a combination of both

• Degenerative changes of disks with aging

  • Lose height and begin to bulge

  • Lose water, begin to dry out and stiffen

  • Settling or collapse of disk spaces, loss of height

  • Vertebrae moving closer together

• Body responds to the collapsed disk by forming more bone around the disk to strengthen it

• Stiffening of the spine narrows foramen and pinch the nerve root

Herniated disk or slipped disk

• Jelly-like center pushes against outer ring

• Disk bulges out toward spinal canal, putting pressure on the nerve root, causing pain and weakness to the area supplied

De Quervain’s Tenosynovitis

• Inflammation and stenosis of abductor pollicis lingus and extensor pollicis brevis tendon sheath under the 1st tensor compartment

  • Tendons are tightly secured against radial styloid by the extensor retinaculum

  • Thickening of tendons restrains gliding of  tendons through the sheath

• Caused by forceful, repetitive, or sustained thumb abduction with ulnar deviation of wrist

• Combined forceful gripping and hand twisting

• Often mothers of infants aged 6-12 months, bilaterally

  • Lifting of baby

Rigid thumb spica splint

• ______ mmobilizing wrist in neutral or extension, thumb in radial abduction

• Pain-free position with light thumb function

• Decreases acute symptoms

• Softer splint after symptoms decrease or if rigid splint is non-functional

Local Corticosteroid or Lidocaine Injections

• Reduces inflammation and pressure on tendon for better gliding

• May cause bleeding or brusing, infection, complications with elevated blood glucose, allergic reactions, transient anesthesia, skin hypopigmentation, tendon weakening

Transverse Friction Massage

• Maintain mobility within soft tissue structures, prevent adherent scars

• May be too painful to tolerate

• Pressing the tissue and rubbing it back and forth

  • Loosen knots, increase blood glow, relieve pain

• Small circular movements to penetrate deep tissues

Superficial heat modalities

• Heat penetration <1cm

• Hot packs

• Heating pads

• Paraffin bath

• Infrared

• Fluidotherapy 

Deep heat modalities

• Heat penetration 3-5 cm or more

• Ultrasound

• Shortwave diathermy (SWD)

• Microwave diathermy (MWD)

Thermal Modalities (Cold)

• Used after acute unjury to reduce bleeding by means of vasoconstriction

• Reduce post-injury edema and inflammation

• Raise pain threshold

• Depth penetration depends on intensity and duration of cold application

  • 10-15 mins, several times per day

• 15 minutes to achieve analagesia

• Avoid ice-induced neuropraxia

Thermal Modalities (Hot)

• Analgesic effect

  • Diminish pain + improve tolerance

• Vascular effect

  • Reduce spasm + improve relief

• Metabolic effect

  • Increase blood flow to tissues

  • Connective tissue effect

  • Reduce stiffness + improve extensibility

Dupuytren’s Contracture

• Progressive, painless thickening and tightening of palmar fascia causing the hand to close into a claw-like position

• Repeated small movements of the palm causes deposits of fibrous tissue on tendon sheath of palm and thum

• Becomes impossible to extend finger and hand can become permanently bound

Small nodule on palm

• first symptom of Dupuytren’s Contracture

Epicondylitis

• Subacute or chronic inflammation of myotendinous junction of wrist flexor and extensor muscle groups

• Tenderness and swelling in or near the elbow and pain may radiate from the elbow

• Due to repeated strain of the forearm

Lateral Epicondylitis or Tennis Elbow

• Affects extensor carpi radialis brevis, and occasionally extensor digitorum communis

• Grip strength is reduced in elbow extension

• Pain-provoking movements include gripping, resisted wrist extension, supination, digital extension, and wrist radial deviation

• Occurs more frequently than golfer’s elbow

Medial Epicondylitis or Golfer’s Elbow

• Overuse injury affecting flexor-pronator muscle origin at the anterior medial epicondyle

• Repeatedly bending and straightening elbow 

Counterforce bracing

• Control load through injured tendon

• Reduce tension of tendons at insertion by transferring force farther down arm

• Spread forces to larger area of elbow

Shoulder Tendinitis or Rotator Cuff Syndrome

• Most common shoulder tendon disorder

• Associated with jobs that require elbow to be in an overhead position for long periods

• Cuff consists of four tendons that fuse over the shoulder joint, where they pronate and supinate the arm and help abduct it

Trigger Finger or Thumb

• Tenosynovitis where tendon becomes nearly locked

  • Painful snapping when making a fist

  • Inability to actively extend affected digit

• Inflammation narrows the space within the sheath that surrounds tendon in affected finger

• Discrepancy between volume of flexor tendon and size of pulley lumen

First annular pulley

• common location for trigger finger

Splinting for Trigger Finger

• Alter biomechanics of flexor tendons while encouraging maximal differential tendon glide

• Hand-based, volar orthosis to support involved MCP joint at 0 degrees

• Allow full interphalangeal flexion

Tendon Glides for Trigger Finger

• Hook fist with orthosis, 20 reps every 2 hrs

• Stimulates production of synovial fluid for tendon nutrition, lubrication, and decrease inflammation

Cubital Tunnel Syndrome

• Compression of ulnar nerve below elbow notch

• Tingling, numbness, or pain radiating into ring or little finger

• Resting forearm near elbow on a hard surface

• Reaching over an obstruction

• Bending elbow over sustained periods

Guyon Tunnel Syndrome

• Entrapment of ulnar nerve as it passes through Guyon tunnel in the wrist

• “Cyclist or Handlebar Palsy”

  • Position of hands while holding handlebars give pressure on ulnar nerve in the canal

  • Pressure of holding handlebar + vibrations

  • Bodyweight being supported by hand

  • Hyperextended position of the hand

Nerve Percussion

• Tapping over the nerve

• Positive result

• Tingling or paresthesia in distal nerve 

Nerve Compression

• Provoke signs of nerve involvement by placing the involved regions in a compromising position

Stress Testing

• Provoke symptom associated with radial tunnel or pronator syndrome

  • Often found in cashiers

• Individual may be requested to perform repetitive forearm rotation by turning over cards to stimulate scanning in a checkout line

Repetition

• Performance of same motions over and over within a given time period

• Hallmark of industrial revolution

  • More efficient by simplifying motion

• Information age continues propensity through computer use, instrument control panels, service occupations

• Muscle fatigue, tissue strain, tissue density changes

<30s, >50%

• Strain and magnitude supersede repair

  • Cycle time: ___

  • ____ of cycle time spent performing the same fundamental function

Force

• Mechanical effort required to carry out movement or to prevent movement

• Exerted against a work piece or tool, or against gravity, to stabilize body segments

Posture

• Body segments are aligned vertically and center of gravity passes through all joint axes

• Compression forces are distributed evenly over weight-bearing surfaces, with no excessive tension exerted on ligaments and muscles

• Functionally demands vision, reach, manipulation, strength, and endurance

• Constrained by relationnship of person’ts anthropometry and layout of workplace

Mechanical Compression

• External pressure placed on human tissue

• Leaning on one’s wrist or elbow on the edge of the table