The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker is appealing the decision made by the Workers Compensation Board ("WCB") that their claim is not acceptable. A hearing was held on March 24, 2026 to consider the worker's appeal.

Issue

Whether or not the claim is acceptable.

Decision

The claim is acceptable.

Background

On August 6, 2024, the employer submitted an Employer’s Accident Report to the WCB indicating the worker sustained an injury to their right knee on June 28, 2024. The report stated that “Excessive driving causing progressive knee injury to a pre-existing condition.” and was reported to the employer on July 1, 2024. The worker provided their Worker Incident Report to the WCB on August 29, 2024, stating that on June 28, 2024, their right knee was injured after prolonged driving. The worker noted they drove between 2,500 and 3,000 kms, which after caused their right knee to lock up and they were unable to walk or drive.

The worker’s report also included a Short Term Disability Claim form, completed by the worker’s treating healthcare provider on August 26, 2024. It noted the worker’s primary diagnosis of right knee chondrosis and that the worker has been treated for the injury since March 2024. The physician described the worker’s prognosis for recovery from the injury as “not good” until the worker undergoes a knee replacement. The physician further noted on the form, the worker had been treated for a similar injury in December 2023 and described the worker’s symptoms as locking of the right knee with movement in a certain way, especially when driving. The treating physician recommended the worker not drive or perform physical activities like going to the gym or playing pickleball. Also included with the form was an August 15, 2024 report from the worker’s treating orthopedic surgeon. The treating surgeon recorded the worker’s reporting of pain to the anterior aspect of their right knee since June 2024, locking sensations with recurrent effusions and pain that has affected their activities of daily living, including sleep. On examining the worker, the surgeon noted a small effusion, slight tenderness to the medial and lateral joint lines and on palpitation to the inferior pole of the patella. Diagnostic imaging was noted to be mostly normal with changes to the articular cartilage involving the patellofemoral compartment indicated. The orthopedic surgeon diagnosed right knee chondrosis and recommended against surgery. Continued physiotherapy was recommended and if the worker’s knee did not respond, intraarticular injections were suggested.

The WCB contacted the worker on September 9, 2024 to discuss their claim. The worker advised the WCB their right knee locked up while they were performing their job duties involving driving and noted their belief that driving long distances contributes to their symptoms. The worker further noted their job duties included one week, every 2 months, of driving longer distances.

The WCB provided the worker with a decision letter on September 12, 2024 advising their claim was not accepted because the WCB was unable to establish that the worker sustained an injury on June 28, 2024 and the medical information on file supported their knee difficulties were due to a pre-existing condition. The worker requested reconsideration of the WCB’s decision to the Review Office on October 4, 2024. In their submission, the worker noted their belief the injury occurred as a result of an aggravation of their pre-existing osteoarthritis. The worker also noted they had not experienced their knee locking and becoming inoperable until they exceeded 5 to 10 hours of driving. In addition, the worker also attached a copy of a previous Appeal Commission decision accepting the claim of a worker who developed osteoarthritis after 30 years of employment in support of their request. On November 4, 2024, the Review Office determined the worker’s claim was not acceptable. The Review Office found the worker’s delay in reporting their right knee issues as a work injury and the medical information supporting June 28, 2024 was not the first time the worker had issues with their right knee made it difficult to establish the worker sustained a right knee injury on that date. As well, the Review Office found a MRI report from March 11, 2024 and an August 15, 2024 medical report indicating the worker’s right knee was stable and contained no findings to support a significant change in the structure of the worker’s right knee.

On August 8, 2025, the worker’s representative provided additional information to the Review Office and requested reconsideration of the previous decision. The representative provided a copy of an email discussion between the worker and the employer noting on July 2, 2024, the worker advised the employer their right knee was sore after driving a long distance the previous week. As a result, they had been ambulating on crutches, using medication and had difficulty sleeping that weekend and the worker requested to take some sick time to recover. The discussion also included a July 15, 2024 email from the worker to the employer advising that the worker was aware their knee difficulties were pre-existing however, the excess driving they did around June 28, 2024 caused an aggravation of that condition and the worker would be seeing a specialist on August 15, 2024, after which they may file a WCB claim. The representative noted this information supported the worker reported their difficulties to the employer in a timely manner and suffered an aggravation of their pre-existing right knee difficulties so their claim should be accepted. On October 1, 2025, the Review Office again determined the worker’s claim was not acceptable. The Review Office found the worker was having symptoms consistent with their pre-existing right knee condition and did not support the worker sustained an accident arising out of or in the course of their employment on June 28, 2024.

The worker’s representative filed an appeal with the Appeal Commission on October 16, 2025 and a hearing was arranged.

Reasons

Applicable Legislation

The Appeal Commission panels are bound by the provisions of The Workers Compensation Act (the "Act"), regulations under that Act, and the policies established by the WCB's Board of Directors. The provisions of the Act in effect as of the date of the worker’s accident are applicable.

Section 4(1) of the Act provides that where a worker suffers personal injury by accident arising out of and in the course of employment, compensation shall be paid. The Act defines “accident” in Section 1(1) as follows:

(a) a chance event occasioned by a physical or natural cause, 

(b) a wilful and intentional act that is not the act of the worker, or 

(c) an event or condition, or a combination of events or conditions, related to the worker's work or workplace,

that results in personal injury to a worker, including an occupational disease, post-traumatic stress disorder or an acute reaction to a traumatic event.

Section 17 of the Act requires that a worker give notice of an injury caused by an accident to their employer as soon as practicable and no later than 30 days after the accident occurs.

The WCB has established Policy 44.05, Arising Out of and in the Course of Employment (the "Arising Policy") which confirms that an injured worker will be entitled to compensation under the Act if the WCB determines that they suffered a personal injury by accident and that the accident arose out of and in the course of employment and provides how the WCB determines whether an accident arose out of and in the course of employment.

The WCB has also established Policy 44.10.20.10, Pre-existing Conditions (the "Pre-existing Policy"), to address eligibility for compensation in circumstances where a worker has a pre-existing condition, which is defined as any medical condition the worker had prior to their workplace injury. The Pre-existing Policy outlines that the WCB will not provide benefits for disablement resulting solely from the effect of a worker’s pre-existing condition as such a condition does not fall within the definition of personal injury by accident arising out of and in the course of employment. It also outlines that a pre-existing condition may contribute to the severity of a workplace injury or significantly prolong a worker's recovery, and workplace injuries can impact pre-existing conditions. A temporary worsening of a worker’s pre-existing condition is considered an aggravation of the pre-existing condition and a permanent worsening of the worker’s condition because of a workplace injury is an enhancement of the pre-existing condition.

Worker’s Position

The worker was present at the hearing and represented by a worker advisor. The worker and their representative answered questions posed by members of the appeal panel.

The worker's position, as outlined by the worker advisor in their written and oral submissions, is that the evidence supports a finding that the worker injured their knee in the course of employment.

The worker submits that their injury satisfies the definition of accident under the Act, by constituting a chance event occasioned by a physical or natural cause.

The worker’s position is that driving a work vehicle for an extended period of time, such as the worker had done, qualifies as an accident as defined by the Act. The worker’s evidence is that it was unexpected and sudden and occasioned by the repeated application of the gas pedal and using their right knee that had a pre-existing condition. The worker states that the combination of those factors led to their knee locking up and additional symptoms such as swelling and difficulty walking. These symptoms necessitated time off work.

The worker submits that they were injured arising out of and in the course of employment and their claim therefore ought to be accepted.

Employer’s Position

The employer did not participate in the appeal.

Analysis

The worker's appeal arises out of the WCB's decision that the worker's claim is not acceptable. For the appeal to succeed, the panel would have to find that the worker sustained injury as a result of an accident arising out of and in the course of their employment. As detailed below, the panel was able to make such a finding and therefore the worker's appeal is granted.

The evidence establishes that the worker’s job duties periodically required extensive driving. The worker advised the WCB that their job duties included significant long-distance driving approximately one week every two months. The evidence further establishes that during the period leading up to June 28, 2024, the worker drove between approximately 2,500 and 3,000 kilometres for work purposes.

The panel accepts the worker’s evidence that following this prolonged driving, their right knee symptoms significantly worsened. The worker described their knee locking, swelling, pain, and difficulty walking and driving. The panel notes this account is generally consistent throughout the claim file and is corroborated by the July 2, 2024 email to the employer in which the worker reported that their knee was sore after the previous week’s long-distance driving, that they had been using crutches and medication, and were experiencing difficulty sleeping due to their knee pain.

The panel places weight on the fact that the worker reported their symptoms to the employer shortly after the driving duties occurred. While the WCB claim itself was not filed until later, Section 17 of the Act concerns notice to the employer, and the evidence supports that the employer was made aware of the worker’s difficulties within days of the incident. The July 15, 2024 email further supports that the worker contemporaneously connected the worsening of their condition to the excessive driving performed around June 28, 2024.

The panel acknowledges the worker had a significant pre-existing right knee condition. Medical evidence confirms the worker had prior treatment for right knee difficulties, including chondrosis and osteoarthritic changes, and had experienced symptoms before June 2024. However, the existence of a pre-existing condition does not preclude claim acceptability. The Pre-existing Policy specifically contemplates circumstances where workplace duties aggravate a pre-existing condition.

The panel is unable to conclude that the worker’s symptoms following the June 2024 driving were solely the result of the natural progression of the pre-existing condition. Rather, the evidence supports that the prolonged and repetitive driving duties materially contributed to a worsening of the worker’s symptoms.

The worker’s evidence was that although they had prior knee issues, they experienced a marked increase in symptoms when required to drive for extended periods, particularly beyond 5 to 10 hours. The panel finds this evidence credible and consistent with the medical reporting. The treating physician noted symptoms of locking occurring especially when driving, and the worker’s orthopedic surgeon recorded ongoing pain, recurrent effusions, and interference with activities of daily living following the June 2024 period. The evidence demonstrates a change in the worker’s level of symptoms and functional ability following the prolonged driving duties.

On a balance of probabilities, the panel finds that the worker’s prolonged work-related driving duties was consistent with an accident and therefore finds the worker sustained a personal injury by accident arising out of and in the course of their employment within the meaning of sections 1(1) and 4(1) of the Act. Accordingly, the worker’s claim is acceptable.

Panel Members

R. Lemieux Howard, Presiding Officer
J. Peterson, Commissioner
M. Kernaghan, Commissioner

Recording Secretary, J. Lee

R. Lemieux Howard - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 22nd day of May, 2026