Repetitive Motion Injuries (1.00)
Benefits of Ergonomics
Ergonomics helps to prevent injuries Reduced fatigue and discomfort Increased productivity Improved quality of work Improved quality of life
Definition of Ergonomics
Ergonomics is the science and practice of designing jobs and workplaces to match the capabilities and limitations of the human body." Simply put: "fitting the job to the worker" The goal of ergonomics is to create jobs, tools, equipment and workplaces that fit people, rather than making people adapt to fit them.
Carpal tunnel syndrome
Occurs from chronic swelling of the flexor tendons within the carpal tunnel of the wrist. -Impingement of the median nerve -Thumb, index, middle, half of ring finger affected Symptoms include: Pain in the first three fingers and the base of the thumb Numbness in these areas Paresthesias in these areas
Why is it important to report symptoms early?
Some WMSDs can become chronic, where symptoms don't go away, and these can be very serious. They can even result in lost work days, permanent disability, or even surgery. Early treatment is often very simple and successful.
Awkward Postures
Some parts of your job may require you to move into or maintain postures that aren't neutral, and these are considered awkward postures. They include things like the following: 1. Working with your hands over your head or your elbows above your shoulders. 2. Repetitively lifting your arms up overhead can lead to a shoulder or elbow WMSD. 3. Holding your arms up overhead without bringing them down can also cause problems. 4. Neck Bent more than 30 degrees (neck muscle strain) 5. Back bent more than 30 degrees (back muscle strain) 6. Squatting - Squatting is a good alternative to bending at the waist, but only for short periods of time. If you squat for too long, it builds up pressure behind the kneecap, and it can cause damage to the knee. 7. Kneeling (knee injuries) 8. Wrists Bent in any direction *These awkward postures can cause problems when maintained for more than 2 hours per day *look at slides 12-17
Reducing intensive keying/mousing
Spread keyboard and mouse work throughout the day Use macros for common functions Take stretch pauses Improve your posture and move around as much as possible
Reducing Awkward Lifting
Store items where you won't have to bend or reach to lift them - Avoid storing things on the floor unless you use a hand truck to move them - Avoid storing heavy items above your shoulders. - Place them on a surface between knee and waist level, instead. Use rolling stairs to get items down from high shelves
Low Back Strain vs HNP
Strain vs HNP (herniated disc) -Muscle spasm vs. Radiculopathy History Physical Exam Straight leg raise Strength Sensory Diagnostics X-ray vs. MRI Treatment Physical Therapy vs. Surgical intervention
Reducing Heavy Lifting
Take smaller loads at one time Use mechanical assistance - handtrucks, carts, hoists, conveyors Get help from a co-worker
Lateral epicondylitis (tennis elbow)
Tendonitis of the wrist extensor tendons near their origin (also known as tennis elbow although the majority of people with lateral epicondylitis have never played tennis). Symptoms: Pain on the lateral portion of the elbow over the lateral epicondyle. Pain aggravated with activities such as grasping, pushing, pulling and lifting. As it progresses, the pain may become persistent even at rest DX: localized tenderness in the region of the lateral epicondyle. Pain is also reproduced with the patient extending their wrist under resistance
Risk Factor 2: High Hand Force
High hand force is developed when your hands or fingers hold or squeeze something that requires some effort. This can strain the muscles in your hands and arms as well as the tendons that attach the muscles to bones. Measure pressure with dyanamometer
Flexors vs Extensors
THE WAR IS BETWEEN FLEXORS EXTENSORS CONSTANT BATTLE: Flexors tend to be stronger than extensors Think of positions for splinting/casting POSTURE IS THE MEDIATOR
Reducing repetition
Arrange work to avoid unnecessary motions Let power tools and machinery do the work Spread repetitive work out during the day Take stretch pauses Rotate task with co-workers if possible Change hands or motions frequently
Cubital tunnel syndrome
Caused by resting the elbows on hard surfaces such as an unpadded table or armrests. The ulnar nerve impingement. Ring and little fingerpressure near the elbows. Symptoms include: Pain in the ring and little fingers Paresthesias in these areas Numbness in these areas
Common UE Repetitive Motion Diseases
DeQuervain's Tenosynovitis Carpal Tunnel Syndrome Cubital (ulnar) Tunnel Syndrome Lateral & Medial Epicondylitis Rotator Cuff Tenosynovitis/Entrapment HAVS/VWF
What are some of the symptoms commonly seen in most of WMSDs?
Discomfort Pain Numbness Burning Swelling Change in color Tingling Tightness, loss of flexibility
What can we do?
EDUCATE workers to recognize and report symptoms EARLY
Avoid holding onto objects for long periods
Grip forces are also a problem if you hold onto an object for a long period. (Retractors in surgery) You can avoid this by: Use CLAMPS to hold onto work Place items on carts rather than carrying them Put down a tool when not actually using it
HAVS Diagnosis
HISTORY AND PHYSICAL At risk - check annually TESTS include: Arteriography Skin thermography Sensory tests Two point discrimination Pinprick touch, and Temperature sensation.
Heavy Lifting
Most people are aware that lifting heavy objects increases the risk for injury. The load on the low back when lifting something heavy can strain the muscles and eventually damage the disks in your spine. The load can strain the muscles in the shoulders and upper back as well. Squat to put weight on legs
Risk Factor 3: Highly repetitive motions
Motions are considered "highly repetitive" when you use the same part of your body to make an identical motion over and over again without pauses. Most repetitive motions involve the hand, wrist, arm and shoulder, but there are also repetitive motions of the neck and back. Making the same motion repeatedly can cause a lot of wear and tear on the joints being used, and if you don't rest to allow time for them to heal, the damage can just keep building up. Repetitive motion can be a problem when maintained for more than 2 hours a day.
DeQuervain's Tenosynovitis PE and treatment
PE: slide 48 (Finkelstein's test) Tx: Stop offending act. Splint- thumb spica NSAID Steroid injection Surgery
Rotator Cuff Injury
Pain is the most common symptom Located anterolaterally and superiorly and referred to the level of the deltoid insertion with full-thickness tears. Pain is aggravated in activities where the arm must be in an overhead or a forward-flexed position. In an acute injury, pain suddenly is elicited after a fall, after lifting of a heavy object, or even after a trivial amount of force.
Low Back Strain: NIOSH Lifting Equation
RWL = LC x HM x VM x DM x FM x AM x CM RWL, Recommended WEIGHT LIMIT HM, the Horizontal Multiplier factor, VM, the Vertical Multiplier factor, DM, the Distance Multiplier factor, FM, the Frequency Multiplier factor, AM, the Asymmetric Multiplier factor, CM, the Coupling Multiplier factor *don't need to memorize, just used to determine recommended weight limit and is based off of many factors
Grip Strength
The amount of force required to grip something depends on a number of factors; one of the most important of these is how you grip it. A power grip can be 5 times stronger than a pinch grip Your grip strength DECREASES when you: Bend your wrists Pick up slippery items Wear poorly fitting gloves Have cold hands
What causes WMSDs?
There are many things that everyone does on the job and at home that could contribute to a WMSD if they are done for long enough periods of time. Risk factors include: Awkward Postures High Hand Force Repetitive Motions Repeated Impacts Heavy, Frequent, or Awkward Lifting Moderate to High Hand-Arm Vibration
Reducing Frequent Lifting
Use mechanical assistance Slide objects instead of lifting them Rotate lifting tasks with co-workers if possible
Vibration Syndrome vs Vibration Induced White Finger
VS: A group of symptoms related to the use of vibrating tools and includes - some or all of the following: Muscle weakness, muscle fatigue, pain in the arms and shoulders, and vibration-induced white finger. VWF: AKA "Dead Finger" or "Dead Hand" "Raynaud's of Occupational Origin" The result of impaired circulation (poor blood supply in the fingers, caused by the prolonged use of vibrating tools. VWF may appear after only several months on the job, or may not appear until twenty to forty years on the job
When will a risk factor lead to a WMSD?
Whether or not a risk factor will result in a WMSD depends on: DURATION- how long you are exposed to it FREQUENCY- how often you are exposed to it and how much rest you get in between INTENSITY - how much of the risk factor there is COMBINATIONS of risk factors, where you are exposed to more than one risk factor at a time. *The more risk factors you have at once, the more likely an injury will occur.
Reducing power grip force
1. One of the best ways to reduce grip forces is to use power grips instead of pinch grips wherever possible. Examples include: Pick objects up from the bottom using whole hand Attach handles or use lift tools Build up handles on small tools to reduce grip force 2. Pick up smaller loads 3. Use power tools instead of hand tools 4. Keep tools in good working order 5. Use lighter and more balanced tools 6. Use two hands 7. Keep your wrists straight *look at slide 26
DeQuervain's Disease
A combination of tendonitis and tenosynovitis of extensor pollicis brevis and abductor pollicis longus. Symptoms include: Swelling Pain at the base of the thumb (1st dorsal compartment)
Tendonitis
A common RMI of the wrist, elbow and shoulder. Occurs when we continually stress the tendons, causing them to become inflamed. Symptoms of tendonitis include: Point tenderness Swelling Pain when in motion
Neutral postures
A good posture is one that places the least amount of stress on your joints and muscles. This is referred to as NEUTRAL POSTURE. It takes the strain out of your muscles and joints and allows them to work more efficiently. *look at slide 11
Risk Factor 1: Awkward postures
Awkward postures are body positions that stress the muscles and joints. If you work in these positions too frequently or for too long at a time, the stress can result in injury. There are a number of different postures that you might get into at work or at home that feel awkward, and any of these might result in injury over time. However, there are a limited number that are a known risk for injury at work, and those are the ones that we'll talk about in this presentation.
Reducing Awkward Postures
Change workstation heights & display heights Tilt or rotate the work Use platforms Bring items within easy reach Pause to stretch every once in a while if you do have to work in an awkward posture for any length of time
Symptom recognition
Common symptoms: Pain is persistent, severe or worsening Pain radiates Symptoms include numbness or tingling Symptoms keep you from sleeping at night
HAVS
Hand-arm vibration is caused by the use of vibrating hand-held tools, such as pneumatic jack hammers, drills, gas powered chain saws, and electrical tools such as grinders. The nature of these tools involves vibration (a rapid back and forth type of motion) which is transmitted from the tool to the hands and arms of the person holding the tool. XYZ Axis Time, intensity and frequency HAVS injuries: Vibration Syndrome, Vibration Induced White Finger
What do these symptoms mean?
Having one or more of these symptoms doesnt necessarily mean you have an injury, though. Everyone has had muscle aches or stiffness after working or exercising hard, especially when you're not used to it. Usually these symptoms go away as you rest or as you get used to the work. That's different from symptoms of injury, which last longer or include things like numbness and tingling that mean something more serious might be going on. Sometimes these symptoms might make it difficult to do your job or things around the house, or they might wake you up at night and keep you from getting a good night's sleep.
Intensive keying and mousing
Intensive keying involves highly repetitive movements of the fingers for a long duration - 4 or more hours per day - doing tasks like data entry or transcription. Intensive use of the MOUSE for more than 4 hours per day can also be a risk factor for injury due to the following factors: Reaching for the mouse on the right Gripping the mouse Repetitive clicking
Awkward Lifting
Lifting even moderate loads while bent over or reaching up or out can also place you at risk of injury, to either your back or your shoulders. When you bend over to pick something up from below your knees, not only does your back have to lift the object, but it also has to lift the weight of your upper body. Something else to keep in mind is the same stresses are there when you lower something as when you lift it.
Risk Factor 3: Heavy, frequent or awkward lifting
Lifting loads against gravity places major stresses to the lower back.
Rotator Cuff Injury Test
Neer impingement test. The patient's arm is maximally elevated through forward flexion by the examiner,( causing a jamming of the greater tuberosity against the anteroinferior acromion). Pain elicited with this maneuver indicates a positive test result for impingement.
Frequent Lifting
Repetitive lifting can be just as hazardous as heavy lifting because of the fatigue it causes. When you lift frequently you can tire out the muscles, making them more prone to injury. If your muscles cant handle the load, the strain can be shifted to your joints and the disks in your spine, placing them at risk for injury, too.
Carpal tunnel treatment
Rest Modify offending activities NSAIDs Ice Bracing (cock-up wrist splint) Corticosteroid injection Occupational Therapy (OT) Surgery (Carpal Tunnel Release)
Epicondylitis Treatment
STAGED EXERCISE PROGRAM INITIAL PHASE: Rest NSAIDS- topical & systemic Forearm clasp Cock up wrist splint SECOND PHASE: Stretching program-Wrist flexion then extension THIRD PHASE: Strengthening OTHER: corticosteroid injection ACTIVITY MODIFICATION
Job Modification to Reduce Vibration Exposure
STOP SMOKING Redesign jobs to minimize the use of hand-held vibrating tools. -Multi layer anti-vibratory gloves - Keep hands, tool and body WARM Where job redesign is not feasible, reduce tool vibration. - Shorter exposure times - rest between - substitute a manual tool for a vibrating tool. Whenever possible, high vibration tools should be replaced by improved, low vibration tools designed to absorb vibration before it reaches the handgrip- chainsaws, grinders etc. - If all else fails REMOVE FROM THE EXPOSURE
What are Work-related Musculo- Skeletal Disorders (WMSDs)?
The injuries that ergonomics in the workplace can help to prevent are called work-related musculoskeletal injuries, or WMSDs. WMSDs are also known as: CUMULATIVE TRAUMA DISORDERS (CTDs) REPETITIVE STRAIN INJURIES (RSIs) Overuse injuries WMDSs affect the soft tissues of the body: -the muscles, tendons that connect muscles to bones, ligaments that connect bone to bone, nerves, blood vessels, pretty much every part of your body that's not a bone or internal organ. Usually WMSDs develop gradually, but sometimes can appear suddenly Can be serious (and can even require surgery), if not taken care of early
