Hand, wrist and finger injuries: the rating, not the average

The rating is built from measured findings, not from the name of the injury. The law incorporates the “descriptions and measurements of physical impairments” in the AMA Guides to the Evaluation of Permanent Impairment, 5th Edition. For the hand, wrist and fingers that is Chapter 16, the upper extremities. What counts is what the physician measures in your hand: lost motion, lost sensation, the level of an amputation.

Then the law adjusts it for you. For injuries since 2013, the law requires account to be taken of “the occupation of the injured employee, and the employee’s age at the time of injury.” The same finding in a different job, or at a different age, produces a different percentage.

Then the percentage becomes weeks, and the weeks become money. The weeks per point rise as the rating rises, and the statute says the figures “shall be cumulative.” How that arithmetic works.

A published average blends fingertips with thumbs, older injuries with newer ones, and settlements that kept future medical care open with settlements that closed it. It describes nobody’s hand. The useful question is whether your number was built correctly.

Notice step 2. Losing the entire little finger is 10% of the hand before the hand is converted to anything. The thumb counts twice as much as the index finger and four times as much as the little finger.

The 2005 schedule gives each part of the hand its own impairment numbers, and the first field of your rating string tells you which one was used.

Two things follow. A code from the wrong line is a checkable error; carpal tunnel coded as a wrist motion loss is the classic one. And sensory loss in a finger has its own lines. A numb fingertip after a laceration is a finding, and it belongs in the examination.

The most common complaint after a hand injury, “I can’t hold anything,” is the hardest one to rate.

In carpal tunnel and other compression neuropathies, it is excluded. The Guides give no additional impairment for decreased grip strength in those conditions. Why.

Elsewhere it is narrow. The schedule has a line for grip and pinch strength, but Chapter 16 permits a strength rating “only in the rare case,” and not where there is decreased motion, pain, or deformity. The same rule at the shoulder. If your hand is also stiff or painful, strength is not rated on its own.

Grip still belongs in your work restrictions, and restrictions decide whether you are paid while off work and whether you can go back to the job. If the doctor won’t write them.

These have their own page, and the short version is this:

De Quervain’s tenosynovitis and trigger finger have no diagnosis value. They are rated on wrist, thumb or finger motion, and if treatment works and motion returns, the permanent rating is zero. Your right to treatment and to temporary disability while you are off work does not depend on that. And bilateral carpal tunnel should produce two rating strings, one per hand, each converted and then combined. Carpal tunnel and repetitive strain. · I think I have carpal tunnel.

Amputation is rated at fixed values keyed to the level of the amputation, then run through the same conversions. How amputations are rated.

It also changes temporary disability. Under § 4656(c)(3)(C), “amputations” get up to 240 compensable weeks of temporary disability within five years of the date of injuryDate of injury For a cumulative or occupational disease claim, the law sets it as when you first suffered disability and knew or should have known it was work-related — not when the wear began. Almost every deadline runs off this., instead of 104. The statute does not say “major” or “of a limb.” The defense argues that fingertip losses and surgical revisions fall outside it. The law requires the workers’ comp statutes to be “liberally construed by the courts with the purpose of extending their benefits.” The question is contested, and a worker cut off at 104 weeks after losing part of a finger should not accept that as settled.

What gets left out of the rating: a neuroma at the site, complex regional pain syndrome after a crush or amputation, cold intolerance, and grip and pinch limitations. Loss of both hands, “or the use thereof,” is conclusively presumed to be total permanent disabilityPD Permanent Disability. Compensation for lasting impairment. A different and much lower weekly rate — 2026 maximum $290/week..

If a machine did it, the machine is evidence. Do not let it be repaired, modified or scrapped. A missing or bypassed guard can mean a product case against the manufacturer that pays what comp does not. I cut my hand at work.

A tendon or nerve injury is not a simple laceration. Say specifically what you cannot do: grip, pinch, hold small objects, feel temperature, work in the cold. The functional description is what the rating is built from.

Watch for CRPS after a crush or fracture. A wrist fracture that healed on imaging, followed by a hand that does not work, is what complex regional pain syndrome looks like. The Guides look for at least eight of eleven objective signs at the time of the examination, and that is where these cases are lost. CRPS.

Complications of treatment are part of the claim: a failed surgery, hardware problems, a nerve injured during a procedure. Compensable consequences.

Treatment is measured against a guideline that changed on January 2, 2026. That day the MTUSMTUS Medical Treatment Utilization Schedule. California’s treatment guidelines. Four of them — shoulder, elbow, hand/wrist/forearm and traumatic brain injury — were replaced January 2, 2026. Hand, Wrist and Forearm Disorders Guideline (ACOEM, July 14, 2025) replaced the earlier version. A denial resting on the old version is worth a second look. Utilization review.

The law says the Legislature did not intend to overrule Milpitas Unified School District v. WCABWCAB Workers’ Compensation Appeals Board. The court system that decides these cases. 23 district offices statewide. (Guzman) (2010) 187 Cal.App.4th 808. Under Almaraz/GuzmanAlmaraz/Guzman The doctrine permitting a physician to depart from the strict AMA rating where it does not accurately reflect the impairment, using another method inside the “four corners” of the Guides., a physician may depart from a strict application of the Guides where it does not accurately reflect your impairment, as long as the alternative comes from within the Guides.

The physician has to give the strict rating, explain why it fails, identify the alternative method, and explain why it is more accurate for you. A bare statement that the rating “does not reflect” your impairment is rejected. That is why it has to be planned before the examination. What Almaraz/Guzman requires.

Expect arthritis, diabetes and old hand injuries. ApportionmentApportionment Dividing permanent disability between industrial and non-industrial causes. It is to disability, not to findings on an image. “shall be based on causation” (§ 4663(a)), and the employer is liable only for the percentage of permanent disability directly caused by the work injury. A prior permanent disability award, including one for the same hand, is conclusively presumed to still exist at the time of the new injury. Under EscobedoEscobedo The en banc decision requiring an apportionment opinion to explain how and why. A percentage without reasoning is not substantial evidence., an opinion has to explain how and why a non-industrial factor caused a percentage of the disability. A number without reasoning is not substantial evidenceSubstantial evidence The standard a medical opinion must meet to support a finding.. How to read it.

• Tell every doctor which hand is dominant, and make sure the first report says it — It bears on your restrictions, on whether you can return to your job, and on the strain your other hand takes over.
• Report both hands if both hurt — Overuse of the other hand is a compensable consequenceCompensable consequence A new problem caused by the original injury or its treatment. Overusing the other side, the joint above or below, a surgical complication., and it has to be claimed. Each hand is rated separately and then combined.
• Get restrictions in writing, in hand terms — Grip, pinch, fine handling, repetitive use, weight per hand, cold, vibration. If they are not written, they do not exist.
• Describe the work in numbers — What motion, how many times an hour, with what force, for how many hours, for how many years.
• Keep the operative report and check every digit in it — A finger in the treatment records but missing from the rating string contributes nothing.
• File on time — Section 5405 generally gives one year from the date of injury. For a hand that wore out over years, the date of injury is set by § 5412. Cumulative trauma.