Msd

MUSCULOSKELETAL DISORDERS Musculoskeletal problems arise from the responses in the human body to physiological and biomechanical demands of physical activity. The nature of those demands (and the responses) changes with the type of task performed, across the spectrum of jobs from those which require very static posture to be held for long periods (by keyboard operators, for example) to the heavy dynamic work of brewery draymen or forestry workers.

Muscle activity Dynamic work

Method of assessing work demands Energy demands

Psychophysic s

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Heart rate

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O2 consumption

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Borg RPE scale

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Maximum acceptable weight of load (MAWL)

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NIOSH Equation

Muscle activity Biomechanica l load -

Posture analysis

Static work

Discomfort or pain

EMG Strength Modelling (Spine compression, joint torques)

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Stature changed

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Notation classification of joint movement RULA

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OWAS

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Body map

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Pain scale

Types of Musculoskeletal Disorders Tendon disorders

Shoulder tendinitis, epicondylitis, de Quervain’s tendinitis, Dupuytern’s contracure, Achilles tendinitis

Nerve disorders Muscle disorder

Carpal tunnel syndrome, thoracic outlet syndrome, radiculopathy, vibration neuropathy Tension neck syndrome

Joint disorder

Osteoarthosis

Vascular disorders

Hypothenar hammer syndrome

Bursa disorders

Knee bursitis

Unspecified musculoskeletal

Cumulative trauma disorder, repetitive strain injury, occupational overuse syndrome, occupational cervicobrachial syndrome

symptoms or multiple tissue disorders

Determination of Factors affecting WRMSD and specific body parts involved Two types of Factors Non-occupational Occupational

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Few Non Occupational Factors OfYounger CTDs Age: Inconsistent relationship. workers are often reporting a higher prevalence of disorders than older workers.

o Gender:

Relative risk is higher in female than male

(Makela et al.,1991,Linton, 1990).

o Acute Trauma o Chronic Disease o Use of birth control pills o Circumstances of Pregnancy

Few Occupational Factors Of CTDs o Repetition: o Force: o Duration of exposure: o o o o o o o

increased duration exposure causes high prevalence of CTD (Jonsson et.al., 1988)

Awkward Posture Static Posture Mechanical stress Contact Stress Temperature Extremes Vibration Psycho Social

REPETITIO N A cycle time of less than 30 seconds or as more than 50% of the cycle time spent performing the same fundamental motion (Silverstein, 1985). Injury may result from repetition when the tissues do not have adequate time to recover High repetitive job causes higher prevalence of CTD (Huang et al., 1988)

FORC E Force is the amount of physical effort required by a person to do a task or maintain control of tools or equipment A pinch grip produces 3-5 times more force on the tendons in the wrist than a grip with the whole hand With excessive force the muscles are contracting much harder than normal, this can lead to stress on the muscles, tendons and joints

AWKWARD POSTURE The body position that minimizes stresses on the body is called neutral posture. Typically the neutral posture will be near the mid-range of any joint’s range of motion Awkward postures refer to the positions of the body (limbs, joints, back) that deviate significantly from the neutral position while job tasks are being performed

STATIC POSTURE The working posture maintained longer than 4 sec. is the static posture. This applies to slight or nonexistent variations around a fixed force level delivered by muscles and other body structures The muscles will become fatigued from a lack of blood flow during a static posture This fatigue can lead to discomfort

CONTACT STRESS

Contact stress is caused by any sharp or hard object putting localized pressure on a part of the body Contact stress will irritate local tissues and interfere with circulation and nerve function

TEMPERATURE EXTREMES Environmental conditions such as extreme heat or cold can place stress on tissues Extreme cold constricts blood vessels and reduces sensitivity and coordination of body parts Excessive heat can result in increased fatigue and heat stress

VIBRATIO N Exposure to vibration can occur while using power tools or while driving equipment. Vibration from power tools can place stress on the tissues of the fingers, hand and arms. Whole body vibration from driving puts stress on the spinal tissues.

PSYCHO-SOCIAL ISSUES Stress, boredom, job dissatisfaction and anxiety can contribute to the possibility of developing a MSD. Psycho-social issues can create increased muscle tension and reduce a person’s awareness of work technique.

Few Cumulative Trauma Disorders         

Carpal Tunnel Syndrome De Quervain’s Syndrome Thoracic Outlet Syndrome Neck and Back injuries Tendonitis Tennis Elbow Strains/Sprains Bursitis Trigger finger

How to Diagnose CTD / MSD problems

Four criteria for diagnosing epidemiology of MSD  Risk indicator  Odds ratio  Prevalent rate ratio  Incidence ratio

 Participation rate  Physical examination  Investigator blinded

How to calculate Odds ratio? An example of calculation for odd ratio for retrospective Epidemiological Study

Phalan’s test

Responses +ve responses -ve responses

Organized Unorganized 36.1(a)

11.1(b)

63.9(c)

88.9(d)

m = a/b; n = c/d m = 3.25 n = 0.72 Odd ratio = m/n =4.51 95% CI = 0.765 – 2.255

Standard error of Odds Ratio (SE) = √ (1/a + 1/b + 1/c + 1/d) 95 % confidence interval (CI) = ln (Odds Ratio) ± 1.96 X SE 90 % confidence interval (CI) = ln (Odds Ratio) ± 1.645 X SE

Physical Examination  History  Inspection  Palpation  Range of Motion  Muscular and Neurological Examinations

Histor y  An accurate history is essential  How Symptoms started (mechanism of injury)?  Duration of complaint?  Location, nature of pain, or symptoms?  Exacerbating or relieving maneuvers?

Inspectio n  General Appearance  Observation of patient’s movement  Look for asymmetry between sides  Swelling  Deformities  Atrophy  Erythema

Palpation

 Palpate for swelling  Palpate for Warmth  Palpate each area of the structure in turn evaluating for pain and abnormalities as compared to the other side

Range of Motion (ROM)  Passive

(Patients allow the examiner to move the body part)

 Active(Patients move the body part by themselves)

 Resisted (Patients move their body part while examiner holds the part steady)

Range of Motion (ROM) Symptoms to be observed  Nature of the movement  Presence of “Popping” or Crepitus  Range of movement  Presence of pain

Range of Motion (ROM)  Positive Passive ROM: Stress located within the joint

 Positive Active ROM: Problems within both tendon and joints

 Positive Resisted ROM: Problems within both tendon and muscle

Few selected Musculoskeleta l Disorders (MSD)

Carpal Tunnel Syndrome It is a nerve compression problem. (CTS)

Compression in median nerve at the wrist causes this CTS. Carpal tunnel syndrome is often the result of a combination of factors that increase pressure on the median nerve and tendons in the carpal tunnel The main contributing factors are

Palmar ap oneurosis Median nerve

 Trauma or injury to the wrist  Over activity of the pituitary gland  Hypothyroidism  Rheumatoid arthritis  Mechanical problems in the wrist joint  Work stress  Repeated use of vibrating hand tools  Fluid retention during pregnancy or menopause  Development of a cyst or tumor in the canal

How to diagnose? By physical examination of the hands, arms, shoulders, and neck  The wrist can be examined for tenderness, swelling, warmth, and discoloration.  Each finger should be tested for sensation  The muscles at the base of the hand should be examined for strength and signs of atrophy.  Specific tests (Phalan’s tests, Tinel’s tests)  By nerve conduction study: Electrodes are placed on the hand and wrist. Small electric shocks are applied and the speed with which nerves transmit impulses is measured.

•Phalan’s test (Phalen,1966): The patient place both flexed wrist into opposition and applies slight pressure for 30-45 seconds.

De Quervain’s It is a type of tendinitis. Tendinitis is Syndrome

inflammation of tendon. Inflammation of the tendon of the abductor pollicis longus and the extensor pollicis brevis caused de Quervain’s syndrome.

Point of discomfort

Causes of de Quervain’s syndrome

 Swelling of the compartment lining of the tendon  Repetitive motion of the thumb constantly being required to move up and down, Pinching gripping or squeezing Gardening Knitting keyboarding  Awkward use of thumb muscles/tendons.  Muscle imbalance

How to diagnose?  By physical examination of the wrist  The wrist can be examined for Tenderness, and occasional swelling along the thumb extensor tendons  Specific tests (A positive Finklestein's test)  Ultrasonic diagnosis

• Finkelstain’s test (Mcmurtry,1978): the patient is instructed to grasp the thumb of the affected hand with the other fingers and actively pull the thumb towards the small finger.

Tennis Tennis Elbow is actually tendinitis of the wrist Elbow

extensor muscles. A sprain of elbow tendons between forearm and upper humerus causes Tennis elbow. Micro tears in part of the tendon surrounding the elbow and muscle coverings are the first stages in Tennis Elbow development. It is the lateral elbow pain and tenderness over the lateral epicondyle.

Causes of Tennis elbow  Exactly what causes tennis elbow is unknown.  Tennis Elbow can be caused by injury, repetitive movement, strain or the overuse of muscles.  Muscles that are strained or overused, they become inflamed, and painful to the touch.  Incorrect grips, poor hitting positions, using a metal framed tennis racquet, improperly carrying a briefcase or other heavy object, or spending too much time using isolated muscle groups in the elbow area are the main causes.

How to diagnose?  The individual observation and recall of symptoms, a thorough medical history and physical examination by a physician  Magnetic resonance imaging (MRI) has been shown to be helpful in diagnosing cases of early tennis elbow  EMG also are sometimes obtained  X rays are usually always negative because the condition is primarily soft tissue in nature

Thoracic Outlet Syndrome (TOS) difference of cervical rib or a fibrous Anatomical band that cause impingement of lower part of the brachial plexus, causing pain down the ulnar side of the arm and forearm and some times in the hand. Compression occurs when the size and shape of the thoracic outlet is altered. The outlet can be altered by  Exercise  Trauma  Pregnancy  A congenital anomaly  An exostosis  Postural weakness or changes.

Compression of the interscalene space between the anterior and middle scalene muscles-probably from nerve root irritation, spondylosis or facet joint inflammation leading to muscle spasm Compression in the space between the clavicle, the first rib and the muscular and ligamentous structures in the area-probably from postural deficiencies or carrying heavy objects Compression beneath the tendon of the pectoralis minor under the coracoid processmay result from repetitive movements of the arms above the head (shoulder elevation and hyperabduction).

Causes of Thoracic outlet syndrome Static postures  Workers of assembly line workers  cash register operators  students Work often result in a drooping shoulder and forward head posture. Carrying heavy loads  Briefcases and shoulder bags Repetitive over head arm movements

How to Adson or Scalene Maneuver diagnose? The examiner locates the radial pulse. The patient rotates their head toward the tested arm and lets the head tilt backwards (extends the neck) while the examiner extends the arm. A positive test is indicated by a disappearance of the Allen Test pulse. The examiner flexes the patient�s elbow to 90 degrees while the shoulder is extended horizontally and rotated laterally. The patient is asked to turn their head away from the tested arm. The radial pulse is palpated and if it disappears as the patient�s head is rotated the

Rotator cuff Syndrome It is a type of tendinitis. Impingement of supraspinatus on coracoacromial arch causes pain, is the rotator cuff syndrome. The Rotator Cuff of the shoulder includes: Subscapular, Supraspinatus, Infraspinatus, and Teres Minor Muscles.

Repetitive throwing Overhead racquet sports Swimming This type of injury results from repetitive stretching of the rotator cuff during the followthrough phase of the activity. The tear that occurs is not caused by impingement, but more by a joint

How to diagnose?

 Pain, weakness and loss of motion are the most common symptoms reported  A careful history taken and reviewed by the physician  An x-ray to visualize the anatomy of the bones of the shoulder  Physical examination  Special impingement tests  An MRI (magnetic resonance imaging) scan frequently gives the final proof of the status of the rotator cuff tendon.