Chronic pain rehabilitation in workers' compensation: from symptom care to function.

Why do chronic pain claims stall?

Because the pain outlasts the injury, and the usual care pathway has no good answer for that. The worker has had imaging, specialist opinions, a course of physical therapy, maybe an injection. The tissue has had time to heal. The pain continues, the restrictions continue, and the claim sits. Everyone involved can see it is stuck. Nobody is sure what to treat next.

The biopsychosocial model, reviewed at length by Gatchel and colleagues in 2007, explains why this happens. Chronic pain is maintained by the interaction of biology (the original injury, plus a nervous system that has become more sensitive), psychology (how the person interprets the pain, and what they fear it means), and social context (work status, the employer relationship, the claim itself). Treat only the biology after month three and the other two keep running.

Linton's 2000 review of the back and neck pain literature found that psychological factors, including distress, depressed mood, fear-avoidance beliefs, and catastrophizing, were strong predictors of pain becoming chronic and disabling, and that this held across prospective studies. These are not character flaws. They are the predictable effects of months of pain, and the main ones look like this:

• Fear-avoidance. Pain is read as a sign of damage, so the worker avoids whatever provokes it. Avoidance means the nervous system never gets evidence that the movement is safe, so the fear persists. The full loop is described on our kinesiophobia page.
• Deconditioning. Months of guarding and reduced activity cost strength, endurance, and mobility. Work tasks that were routine now feel hard, which confirms the belief that the body is fragile.
• Loss of confidence and role. The worker stops thinking of themselves as someone who does the job. Low mood and poor sleep follow, and both amplify pain.
• Long gaps between appointments. A thirty-minute visit every four to six weeks cannot counter a loop that runs every hour of every day in between. Whatever happens in the clinic, the home environment keeps teaching the old lesson.

What is functional restoration?

Functional restoration is rehabilitation that takes function, rather than pain relief, as the primary outcome. It was developed for chronically disabled industrial back injury patients, and the defining study is Mayer and colleagues' prospective two-year report in JAMA in 1987. The idea was simple and, at the time, unusual: measure what the patient can physically do, increase it on a planned schedule, treat the fear and distress that keep them from doing it, and judge the program by whether they return to productive activity.

In that study, patients who completed the program returned to work at roughly double the rate of a comparison group two years later. One caveat matters. The comparison group was not randomized; it was made up of patients who did not complete the program, often because treatment was not authorized. That means the difference cannot be read as proof that the program caused the result. The paper is still the reason the field changed what it measures.

What a functional restoration program does

1. Measures function at baseline, in quantified terms: lifting capacity, endurance, range of motion, and validated questionnaires, alongside pain.
2. Increases load on a schedule, not on a pain report. The dose goes up because the plan says so, with flares managed rather than treated as a stop signal.
3. Treats the psychology directly. Education about what pain does and does not mean, graded exposure to feared movements, and work on catastrophizing and mood.
4. Sets specific goals tied to the job and to daily life, and tracks progress toward them.
5. Reports numbers, so the treating provider and the claim team see what has changed rather than a narrative.

Modern descendants include interdisciplinary pain programs, work conditioning and work hardening, and, more recently, remote programs that deliver daily practice and coaching at home. They vary a great deal in intensity and quality. The question for a claim team is whether a given program actually does the five things above, and how well it can show that it did. Our pillar guide on evaluating a remote pain rehabilitation program goes through that in detail.

Why don't pain scores alone predict return to work?

Because two workers can both report 6 out of 10 pain and be in completely different situations. One is at work on modified duty, sore but functioning. The other has not worked in eight months and believes a shift would put them back in bed for a week. The pain number does not separate them. Their beliefs about what work will do to them does.

Waddell and colleagues showed this in 1993 when they developed the Fear-Avoidance Beliefs Questionnaire. In chronic low back pain patients, fear-avoidance beliefs about work, measured by what became the FABQ work subscale (FABQ-W), explained more of the variation in work loss than pain intensity or clinical examination findings did. The relationship was strongest for work loss specifically, which is the outcome a claim team cares about.

The FABQ-W asks, in plain terms, whether the worker believes their work caused the pain, whether they think they should be doing their normal work with the pain they have now, and whether they expect to be back at their normal job within a few months. Those beliefs shape behavior far more directly than a pain rating does, and they are the beliefs a function-centered program sets out to change. The kinesiophobia page covers the instruments in more depth.

None of this means pain ratings are useless. They are a reasonable snapshot and a useful trend. The problem is relying on them alone. A claim file that tracks only pain will show a worker who is 'not improving' while their function, confidence, and activity tolerance are all moving. Our guide to measuring functional progress in chronic pain sets out what to track instead, and chronic pain scales explains what a 0–10 rating can and cannot tell you.

What should a function-centered program report to the claim team?

Measures the claim team can act on, at a cadence that matches the plan, with no promises attached. The adjuster needs to know whether authorization is producing change. The nurse case manager needs to know what the worker can now tolerate so restrictions can be updated. The treating provider needs to know what the program is doing so their own plan does not conflict with it.

Two things should not be in the report. The first is item-level questionnaire answers. A total score and its direction of change are useful; the individual responses are clinical material and sharing them beyond the care team serves nobody. The second is a return-to-work date. A program can honestly report where the worker started, how far tolerance has moved, and what remains in the way. Anyone who gives a date is guessing, and the same point is made on our return to work after concussion guide.

How can a remote program fit a workers' compensation care pathway?

As the part of the pathway that happens between appointments. The treating provider stays the treating provider. The remote program adds daily practice at home, regular coaching, and its own clinical oversight, and reports back to the people managing the claim. Done properly it complements the existing care plan and does not compete with it.

Coordination is what makes or breaks it. A sensible arrangement looks like this:

• Treating provider or occupational medicine physician refers, keeps ownership of restrictions and medical decisions, and receives the program's interval summaries.
• Nurse case manager confirms the program fits the current plan, uses the tolerance updates to keep restrictions current, and flags when something in the file changes.
• Adjuster authorizes, receives the same summaries, and can see whether the authorization is producing measurable change.
• Program care team runs the daily practice and coaching, keeps a clinician reviewing the case, and says plainly if the worker turns out not to be a fit.

How Karuna fits

Karuna takes workers' compensation referrals, and the care team confirms coverage case by case. Karuna Virtual Embodiment Training (KVET)™ is a 12-week program done from home on a provided VR headset: short daily embodiment exercises, a weekly one-on-one session with a dedicated pain coach, and a clinician who reviews the case before anything begins and provides oversight throughout. The approach is built on pain neuroscience, graded exposure, and pain reprocessing, which are the same principles functional restoration programs have used for decades, delivered in a form that reaches the home every day. Karuna tracks fear-avoidance alongside function because, as the section above explains, fear is often the thing limiting what a worker can do. Ask the care team at referral what will be shared with the treating provider and the claim team, and how often.

It is designed for pain that has persisted beyond three months and has already been medically evaluated. It is not the right step for an acute injury, for pain that has not been assessed, or for anyone with red-flag symptoms: new weakness or numbness, loss of bowel or bladder control, unexplained weight loss, fever, pain after major trauma, chest pain, or thoughts of self-harm. Those need prompt medical attention first. Our guide to who is a candidate for virtual pain rehabilitation covers selection in detail, and the free consultation exists to answer the fit question honestly for a specific worker.

What has Karuna measured in workers' compensation patients?

Karuna collects outcome data from patients completing the 12-week KVET™ program. The figures below come from a real-world evidence analysis of 50 patients, every one of them injured at work, covered under workers' compensation, and in pain for longer than six months. Measures were taken before and after the program. That population is why the data belongs on this page, and it is also why it needs reading carefully.

The shape of the table is the useful part for a claim team. Activity and confidence moved further than pain did, a median of 49% and 71% against 28% among those who improved. That is what you would expect if fear-avoidance, rather than pain intensity, had been the limit on what these workers could do, and it is the pattern a function-centered program is designed to produce.

Now the limits, which belong in the same breath. This is uncontrolled real-world evidence, not a clinical trial. There was no control group, so the results cannot be compared against no treatment, usual care, or placebo, and they cannot establish that the program caused the change; people change over time for many reasons, and a workers' compensation cohort is subject to many of them. The sample is small and specific: 50 patients, all with work-related injuries, and results may not generalize. All measures are self-reported. Between 21% and 33% of patients did not improve on any given measure. Median improvement is reported among those who improved, so it does not describe the average patient. Nothing in this table is a success rate, and it should not be quoted as one. The full presentation and caveats are on how Karuna works.

What questions should a claim team ask a program vendor?

The same questions you would ask of any treatment you are authorizing, with a few that are specific to function. A vendor that answers them directly is usually worth a closer look. A vendor that answers with a success rate is usually not.

1. What do you measure at baseline, and with which validated instruments? Expect a function measure, a fear-avoidance measure, and pain, at minimum.
2. What do you report, to whom, and how often? Ask to see a sample interval summary before authorizing.
3. Who provides clinical oversight, and when do they review the case? Before the program starts, during it, or only at discharge.
4. How do you decide a worker is not a fit, and what happens then? A program with no exit criteria will keep every referral.
5. What does engagement look like, and what happens when it drops? Daily practice only helps if it happens.
6. How does the program coordinate with the treating provider? Restrictions and medical decisions should stay with the physician of record; the program should never advise a worker to change medication.
7. What outcome data do you have, in what population, and what are its limits? Ask specifically for the share of patients who did not improve. If the answer is a single percentage with no n and no caveats, treat it as marketing.
8. What does the worker have to do, and what do they need at home? Equipment, space, time per day, and how support is provided.

The pillar guide, how to evaluate a remote pain rehabilitation program, expands each of these into what a good answer and a poor answer sound like.

What this means for you

If you are an injured worker

Your pain is real, and so is the frustration of being told the scans look fine. A function-centered program is not a way of saying the pain is in your head. It is a way of treating the things that keep pain going after an injury has healed: fear of moving, lost fitness, lost confidence. Progress in this kind of program usually shows up as being able to do more before it shows up as less pain, so judge it by what you can do this month that you could not do last month. Keep your treating provider informed, do not change any medication without talking to your prescriber, and get urgent care for any of the red-flag symptoms listed above.

If you are an adjuster or nurse case manager

The useful question for a stalled chronic pain claim is whether the file is tracking the things that predict work status. If it tracks pain alone, consider asking for fear-avoidance and function measures at the next review. When evaluating a program, ask for the sample report, the exit criteria, and the share of patients who did not improve. Any program that may help an appropriately selected worker will be able to tell you what it cannot do.

If you are an occupational medicine provider

Functional restoration and its descendants are designed to sit alongside your care, not replace it. The things that make the referral work are the ones you control: a clear baseline, restrictions written in tolerance terms rather than pass or fail, and an expectation that the program reports back in numbers you can use. The FABQ-W takes a few minutes to administer and may tell you more about which of your patients will struggle to return than the examination does.