The Appeal CommissionThe Workers Compensation Act of Manitoba

Applicable Legislation:

The Appeal Commission and its panels are bound by The Workers Compensation Act (the “Act”), regulations and policies of the Board of Directors. Under subsection 4(1) of the Act, where a worker suffers personal injury by accident arising out of and in the course of employment, compensation shall be paid to the worker by the WCB. Subsection 39(2) of the Act provides that the WCB will pay wage loss benefits until such a time as the worker’s loss of earning capacity resulting from the accident ends. Subsection 27(1) provides that medical aid will be paid by the WCB for so long as is necessary to cure and provide relief from the injury.

Worker's position:

The worker appeared at the hearing accompanied by a union representative. It was submitted that while a 58 year old worker with 35 years of physical work may be expected to have degenerative changes in the knee, there was an enhancement which occurred during a training drill on November 13, 2008. Before the date of injury, the worker had no prior pain, restrictive movements or difficulty with his knee. On the date of the workplace injury, there were instantaneous symptoms of swelling, pain with movement and general discomfort and the injury was sustained with textbook mechanics for a meniscal tear. The worker immediately self-administered basic care including ice, rest, elevation and anti-inflammatories for five days until he could see his physician, with whom he already had an appointment. Although two McMurray's tests were negative, these tests are not foolproof or absolute, thus the need for imaging. While the worker's condition was originally diagnosed as a sprain, the symptoms did not resolve over time. They remained as a moderate amount of nagging discomfort which ultimately necessitated surgery for resolve. It was submitted that a cause and effect relationship was supported by the attending surgeon, the worker's general practitioner and initially, the WCB medical advisor (up until August 25, 2009).

Employer's position:

A representative from the employer appeared at the hearing. The employer's position was that the minor incident of November 13, 2008 had no impact on the pre-existing pathology noted in the worker's knee at the time of surgery. The injury was minor in nature (diagnosed as a grade I collateral ligament strain) which did not require any time loss. When seen by his physician five days post accident, the worker was advised to continue with his regular duties. The examination revealed no atrophy, no effusion, full range of movement, normal ligaments and a McMurray's test was reported as being negative. When the worker was seen again on December 17, 2008, the McMurray's testing for a possible meniscal lesion was also negative. There was no further medical treatment from December 17, 2008 to March 18, 2009. Two orthopaedic consultants from the WCB reviewed the medical evidence on file and both concluded that the pathology noted at the time of the August 24, 2009 arthroscopy was unrelated to the November 13, 2008 compensable event. It was submitted that the weight of the evidence, on a balance of probabilities, failed to establish the necessary nexus between the pathology noted at the time of surgery and the compensable accident.

Analysis:

The issue before the panel is whether or not the compensable injury of November 13, 2008 permanently enhanced the worker's pre-existing knee condition. In order for the worker's appeal to succeed, the panel must find that the injury to the worker's left knee on November 13, 2008 either caused or contributed to the need for arthroscopic surgery on August 24, 2009. On a balance of probabilities, we are not able to make that finding.

The worker’s claim was originally accepted by the WCB based on a diagnosis of a medial cruciate ligament (MCL) strain to the left knee. The panel notes that this was the diagnosis proposed in the doctor's first report dated November 18, 2008 by the sports medicine physician who was the first medical practitioner to examine the worker. At the hearing, the worker confirmed that the sports medicine physician conducted a thorough examination of his knee, and performed multiple tests on it. It is notable that the physician was a sports medicine specialist with specific training in musculoskeletal injuries.

On the next follow-up examination on December 17, 2009, the sports medicine physician indicated that the pain was better and that the MCL was healing. The panel notes that on both examinations, the worker was specifically tested for a meniscal tear (McMurray's test), and on both occasions, the result was negative.

The subsequent MRI on June 8, 2009 and arthroscopy performed August 24, 2009 indicated extensive degenerative change in the worker's knee and multiple diagnoses affecting a variety of structures within the joint. The pre- and post-operative diagnoses for the left knee remained the same: meniscal tear, degenerative arthritis. The question the panel must ask is whether there is evidence to satisfy us on a balance of probabilities that either of these conditions were enhanced by the compensable injury.

In the panel's opinion, the evidence does not support the conclusion that the worker's pre-existing knee condition was enhanced. In coming to this result, we rely on the following:

• The initial examinations performed by the sports medicine physician in the month following the workplace incident diagnosed only a grade 1 MCL strain. The sports medicine physician's findings at that time did not indicate a more significant injury to the medial meniscus or other structures in the left knee;
• Although the WCB orthopaedic medical advisor initially acknowledged the possibility that there may be an acute change superimposed on a chronic degenerative change in the meniscus, after being provided with further diagnostic information (ie. the operative report), he later concluded that the operative findings were all degenerative in nature and did not arise out of the compensable injury;
• The orthopaedic medical advisor to Review Office also opined that the probable compensable diagnosis was a musculo-ligamentous strain/sprain of the left knee and that there was no objective medical evidence that the compensable injury changed the anatomical structures of the knee. He further stated that the MRI and operative findings support the conclusion that the changes were entirely degenerative and not traumatic in etiology;
• The panel's interpretation of the attending surgeon's opinion of November 4, 2009 was that the types of injuries the worker experienced at work were likely to accelerate the rate of progression of arthritis. We did not view the attending surgeon as stating a clear opinion that a particular condition found in the worker's knee on surgery was caused by the workplace incident. He did refer to a probable medial compartment meniscal and/or articular cartilage injury, but did not provide any specifics. He also added that there could have been some injury to the patella or synovium, but then said that there was no way of knowing this to have occurred. As the surgeon did not explain why he felt the degenerative findings indicated an acute meniscal and/or cartilage injury, the panel places less weight on his opinion.

The strongest evidence in the worker's favour was the temporal relationship between the change in functional ability before and after the injury. Unfortunately, this alone is not sufficient to convince the panel that there was a permanent enhancement of the worker's pre-existing condition. It is possible for there to have been two concurrent conditions manifesting in the worker's left knee at the time. While the MCL strain was resolving (as was indicated in the doctor's progress report of December 17, 2008), the degenerative condition was progressively worsening, to the point where the worker sought treatment from his orthopaedic surgeon in March, 2009.