Repetitive Strain Injury: When the Job Wears Out a Tendon

A repetitive strain injury is tendon or nerve damage built up by the same motion, grip or posture done thousands of times. At work it most often shows up as tennis elbow, wrist tendon pain or a sore shoulder. Treatment starts with changing the load and rehab. Platelet-rich plasma (PRP) is one option for a tendon that will not heal.

Here is the trap. A cortisone shot into a sore elbow works fast. You go back to the same task the next week. In a large review in The Lancet, people who got cortisone for tennis elbow felt better at first and then did worse than people who got no shot at all by six months to a year. Fast relief, slower healing, same job. That is how a three-month problem becomes a three-year one.

What causes a repetitive strain injury at work?

A tendon is a rope of collagen that ties muscle to bone. Every use makes tiny wear. Rest repairs it. When the work outruns the repair, the tendon starts to break down instead of getting stronger.

Studies of work tasks point to a few repeat offenders:

• Gripping with force: tools, scanners, steering, lifting with the hands.
• Twisting the forearm over and over, palm up and palm down, under load.
• Fast, repeated wrist motion with little rest.

The elbow is a common target. Tennis elbow, called lateral epicondylitis, is pain on the outside of the elbow when you grip, shake hands or lift a coffee cup. Golfer’s elbow is the same problem on the inside. The wrist and the shoulder follow the same rules.

Is it a tendon problem or a nerve problem?

This matters, because the fix is different. Tendon pain is sore at one spot and worse with grip or lift. Nerve trouble, such as carpal tunnel, brings numbness, tingling or weakness in a pattern. Many workers have both. An exam and an ultrasound sort out the tendon. An EMG test sorts out the nerve. Carpal tunnel release and hydrodissection of a trapped nerve are done here in-house.

What treatment comes first for a repetitive strain injury?

The first step is to change the dose of work the tendon gets, without stopping your life:

• Modified duty or a rotation away from the worst task for a few weeks.
• A strap or brace for the elbow or wrist during heavy tasks.
• Rehab that loads the tendon slowly and on purpose. Tendons heal when they are loaded the right way, not when they are kept still.
• Tool and setup changes: a bigger grip, a lower shelf, a lighter scanner.

Most cases get better with this alone. If you are still in pain after about three months of good care, the tendon has likely stalled. That is the point to think about other options.

Where does PRP fit for a tendon that will not heal?

PRP is made from your own blood. We concentrate the platelets and place them into the damaged part of the tendon under ultrasound. The growth signals they carry tell a stalled tendon to restart repair.

Tennis elbow has some of the strongest evidence for PRP. A 2024 review of 11 trials compared PRP with cortisone for tennis elbow. Cortisone did better in the first two months. PRP did better for pain and function at six months and beyond, which is the part that decides whether you keep your job. A 2025 review of orthobiologic guidelines also names tennis elbow as one of the conditions where pooled studies show PRP improves outcomes.

The visit is simple. We use local anesthetic, you stay awake, and most people drive home. The tendon is often sore for about 48 hours. Then rehab picks up again, because PRP works with loading, not instead of it. How many injections you need depends on how the tendon responds. Shockwave therapy is another option for some stubborn tendons.

Who gets a repetitive strain injury?

Anyone whose job repeats the same motion for hours. We see it in warehouse pickers, assembly and packing lines, mechanics, nurses, cooks, hair stylists, drivers and people who type all day. The job sets the load. The body sets how well the tendon keeps up.

That second part is where most care stops looking. High blood sugar stiffens collagen, the protein tendons are made of. Smoking cuts blood flow to tissue that has little to begin with. Poor sleep slows repair. Two workers do the same task, and the one with diabetes is the one whose elbow does not recover. That is why we check the metabolic terrain, not just the elbow.

How is a repetitive strain injury handled in workers’ comp?

A strain that built up over months is still a work injury. The claim turns on the record: what your job asks of your hands and arms, when symptoms started, and what the exam shows. Report it to your employer as soon as you notice a pattern. If you are sent for a functional capacity evaluation, know what it measures before you go.

Comp carriers often will not authorize PRP. An authorization means a payer agrees a service is medically needed. It is not a promise of payment. HSA and FSA funds can generally be used for PRP. We spell out which is which before anything is scheduled.

What happens if you keep working through it?

Pain is the body asking for a change in load. Ignore it, and a sore tendon can become a torn one. Numb it with shot after shot, and you may lose the signal that was protecting you. The goal is not to quit your job. It is to change the dose, heal the tendon and go back to full work with an arm that holds up.

Related reading: knee injury at work, injury and work comp care for Illinois patients and ultrasound-guided injection accuracy.

All orthobiologic care: Our orthobiologics and PRP injections page lists every injury we treat with PRP, bone marrow concentrate and microfragmented fat.

Frequently asked questions

Is a repetitive strain injury covered by workers’ comp?

It can be. A condition that builds up from work tasks counts as a work injury in Missouri and Illinois when the record ties it to the job. Report it to your employer as soon as you notice a pattern.

How long does tennis elbow take to heal?

Many cases settle within a few months with load changes and rehab. Some last a year or longer, especially when the same task continues or after repeated cortisone shots.

Is cortisone bad for tennis elbow?

It often helps for a few weeks. In the long run, studies found people who got cortisone did worse than those who did not. We use it rarely in tendons for that reason.

What is the difference between tendinitis and tendinosis?

Tendinitis means fresh inflammation. Tendinosis means the tendon fibers have started to break down over time. Most long-lasting work strain is tendinosis, which is why rest alone often fails.

Can I get PRP if my claim is denied?

Yes. PRP does not depend on the claim. HSA and FSA funds can generally be used, and we explain the options before scheduling.

Where is Injury Experts located?

Accident and Injury Experts is at 4477 Woodson Rd, Suite 202, St. Louis, MO 63134, next to Lambert International Airport, with parking at the door. Call (314) 887-5866. Directions and hours are on our contact page.

Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP. Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed October 3, 2026.