Case snapshot
At a glance
- Case
- Can a Right Shoulder Injury Be Covered Under an Ontario Workers' Comp Claim?
- Court / Tribunal
- Workplace Safety and Insurance Appeals Tribunal
- Citation
- 2026 ONWSIAT 927 ↗
- Date
- August 13, 2026
- Area of law
- Employment Law
- Key issue
- Whether a right shoulder injury that developed over time could be recognized as a secondary condition under an existing left shoulder workers' compensation claim.
- Outcome
- The appeal was allowed in part: the worker was granted entitlement for a right shoulder partial rotator cuff tear as a secondary condition, while the loss-of-earnings issue was sent back to the WSIB for further adjudication.
- Why it matters
- Workers who develop a new injury in one part of their body because of restrictions caused by a prior workplace injury may be entitled to WSIB benefits for that new injury under their original claim.
Legal principle
The rule from this case
Under Ontario's Workplace Safety and Insurance Act and applicable WSIB policy, a worker can receive benefits for a secondary condition if that condition is causally linked to the original work-related injury. In this decision, the Tribunal found that years of performing modified duties with a restricted left shoulder caused the worker to overuse her right shoulder, eventually producing a partial rotator cuff tear. Because a specialized physician confirmed the causal link and no contrary medical opinion existed, the Tribunal was satisfied on the balance of probabilities that the right shoulder injury was a compensable secondary condition. The standard of proof applied was the civil balance of probabilities, with the benefit of the doubt available only where evidence for and against an issue is approximately equal — not merely where there is some possibility on each side. A speculative possibility is not enough to meet that standard, but here the medical evidence was sufficient to tip the scales in the worker's favour.
Important limits
What this does not mean
This decision does not mean that every new injury a worker develops while doing modified work will automatically be covered as a secondary condition. The Tribunal carefully limited its finding: it granted entitlement for specific tendon tears confirmed by imaging and medical opinion, but denied entitlement for osteoarthritis of the AC joint (which was consistent with age-related change) and for a possible subscapularis tendon tear that was not confirmed. A causal link must be established by medical evidence, not simply inferred from the fact that a worker was on modified duties. The decision also does not resolve the worker's claim for partial loss-of-earnings benefits beyond the 72-month lock-in period. That issue was sent back to the WSIB because the evidence before the Tribunal was incomplete and the worker's own testimony at the hearing was inconsistent on key points. A referral back to the WSIB for further adjudication is not a win or a loss on that issue — it simply means the process continues at the Board level.
Can a new injury be covered under an old WSIB claim in Ontario?
Yes — if the new injury is causally linked to the original workplace injury, it may qualify as a secondary condition under the same claim. In Decision No. 147/26, 2026 ONWSIAT 927 (CanLII), the Workplace Safety and Insurance Appeals Tribunal (WSIAT) recognized a right shoulder rotator cuff tear as a secondary condition arising from a 2012 left shoulder injury, because years of modified duties with a restricted left arm led to overuse of the right shoulder.
This outcome matters for any Ontario worker who has developed pain or injury in a different body part while trying to work around restrictions from a prior workplace injury.
What is a secondary condition under Ontario’s workers’ compensation system?
A secondary condition is a new injury or worsening that is causally connected to the original work-related impairment. WSIB policy provides that workers who sustain secondary conditions causally linked to a work-related injury can receive benefits to compensate for the further impact on their health.
In this case, the worker had permanent restrictions on her left shoulder use following a 2012 packing job injury. Over years of modified sanitation work, she began developing right shoulder pain. A specialist in orthopedic surgery and sports medicine concluded that her right shoulder limitations likely stemmed from overuse caused by her left shoulder restrictions. The Tribunal found no contrary medical opinion, and granted entitlement for the right shoulder partial tear.
What evidence did the Tribunal rely on to connect the two injuries?
The Tribunal relied primarily on a specialist’s medical opinion, the absence of any contradicting medical evidence, and the worker’s own description of her duties. The specialist reviewed the return-to-work memorandum and job duties and concluded that the worker’s employment involved an injuring process tied to her left shoulder limitations.
The Tribunal also noted that the worker’s modified sanitation duties — including covering the production line during co-workers’ breaks — involved movements that exceeded her documented left shoulder restrictions. Over time, this created the conditions for a right shoulder overuse injury. A July 2018 ultrasound found no rotator cuff tear, but a December 2018 ultrasound showed a partial-thickness supraspinatus tear, and an August 2020 MRI confirmed partial tearing of the supraspinatus and infraspinatus tendons.
What did the Tribunal NOT cover under the secondary condition finding?
The Tribunal was careful to limit the entitlement to what the evidence actually supported. Entitlement was granted for partial tears of the supraspinatus and infraspinatus tendons in the right shoulder. However, two other conditions were excluded.
First, a possible tear of the subscapularis tendon was not confirmed by the medical evidence, so no entitlement was granted for it. Second, osteoarthritis of the AC joint was found to be consistent with age-related change rather than a work-related condition, particularly because the specialist did not opine on its work-relatedness. The Tribunal’s medical discussion paper on osteoarthritis supported that conclusion.
How does the benefit of the doubt work in WSIAT proceedings?
The benefit of the doubt applies only when the evidence for and against an issue is approximately equal in weight — not whenever there is some uncertainty. The Tribunal in this decision reaffirmed that a speculative possibility does not meet the balance of probabilities standard, and that the benefit of the doubt is not triggered by mere supposition.
In practice, this means workers need more than a plausible story. Medical evidence that directly addresses causation — ideally from a specialist who has reviewed the relevant job duties and restrictions — carries significant weight. Where no contrary opinion exists, the Tribunal is more likely to find the balance of probabilities satisfied.
What happened with the loss-of-earnings claim?
The worker’s claim for partial loss-of-earnings (LOE) benefits from November 21, 2019 onward was not decided by the Tribunal. Instead, it was sent back to the WSIB for further adjudication.
The Tribunal explained that the worker’s LOE lock-in date under the 2012 accident was January 11, 2018 — 72 months after the accident. Reviewing LOE benefits beyond that date requires meeting specific statutory exceptions under the WSIA. Because the evidence before the Tribunal was incomplete, and the worker’s own testimony was inconsistent on key points (including whether she had returned to full 8-hour shifts before stopping work), the Tribunal concluded that further WSIB investigation was appropriate. This referral is not a final decision on that issue.
Questions and records to discuss with a lawyer
- Do you have medical documentation — such as imaging results or specialist reports — that connects a new injury to the restrictions from your original workplace injury?
- Have you kept records of the physical demands of your modified duties, including any tasks that exceeded your documented restrictions?
- Has the WSIB formally communicated your permanent restrictions to you in writing, and do those restrictions reflect your current functional limitations?
- If your LOE benefits were locked in at 72 months, has there been a significant deterioration in your condition that might qualify for a review under the WSIA exceptions?
- Are there gaps in your WSIB file — such as periods of right-sided complaints — that were not formally investigated at the time?
If you have questions about a WSIB claim, a secondary condition, or a loss-of-earnings dispute, our Ontario employment lawyers can help you understand your options. Workers in the Hamilton and Burlington areas can also reach out through our Hamilton employment law and Burlington employment law pages. Contact UL Lawyers through /connect to discuss your specific circumstances.
This article is automated commentary on a public court decision and is for general information only — not legal advice. Decisions rely on facts unique to each case. If you are affected by a similar issue, contact a lawyer for advice specific to your situation.
FAQ
Frequently asked questions
Yes, if the new injury developed because of the restrictions or overuse caused by your original workplace injury, it may qualify as a secondary condition under your existing WSIB claim. You will generally need medical evidence establishing the causal connection.
Under the Workplace Safety and Insurance Act, the WSIB conducts a final review of loss-of-earnings benefits 72 months after the accident date. After that point, LOE benefits can only be revisited in specific circumstances, such as a significant deterioration in the worker's condition that affects their permanent impairment rating.
When the Tribunal remits an issue, it sends the matter back to the WSIB for further investigation and decision-making rather than deciding it itself. This typically happens when the evidence is incomplete or when the issue was not fully adjudicated at the Board level before the appeal.