The Appeal CommissionThe Workers Compensation Act of Manitoba

Applicable Legislation

The worker is employed by a federal government agency or department and her claim is therefore adjudicated under the Government Employees Compensation Act (“GECA”). Under the GECA, an employee who suffers a personal injury by an accident arising out of and in the course of employment is entitled to compensation. The GECA defines accident as including “a willful and an intentional act, not being the act of the employee, and a fortuitous event occasioned by a physical or natural cause.”

Pursuant to subsection 4(2)(a) of the GECA, a federal government employee in Manitoba is to receive compensation at the same rate and under the same conditions as a worker covered under The Workers Compensation Act (the “WCA”).

In deciding appeals, the Appeal Commission and its panels are also bound by the WCA, regulations and policies of the Board of Directors to the extent that they apply to GECA cases.

The worker in this case already has an accepted claim for a work-related right knee injury that occurred on October 28, 2009. The key issue before the panel was whether the worker's later diagnosis of an ACL tear in that same knee is elated to the October 28, 2009 workplace accident.

Worker's Position

The worker was assisted by her union representative at the hearing. She described how the accident had taken place during a workplace event, and her immediate symptoms thereafter. She explained how the doctor and physiotherapist had been concerned that there might have been a pathology greater than the strain that had been diagnosed early on, and that was the reason why an MRI had been ordered for December, 2009. However, she had already made plans for a year long trip and made arrangements to postpone the MRI for one year, to December 21, 2010, to accommodate that trip.

She indicated to the panel that her physiotherapy had restored considerable function to her knee, and that she was able to lead an extremely active lifestyle on the trip. She travelled with a backpack that weighed 15 kg, and was able to surf, hike to a base camp in the mountains, cycle, and go on extended hikes and walks 3-4 times per week. She states that her knee gave her absolutely no difficulties at all on the trip. She had a knee brace with her, and wore it on occasion, not because of pain issues, but on a preventative basis. Nothing had happened on the trip to her knee, and she did not at any point seek any medical treatment for her knee while she was travelling or on her return to Winnipeg prior to the MRI on December 21, 2010.

She indicated that she returned to Winnipeg in December 2010 with an asymptomatic knee and without any thought of her having any knee problems. She had only gone to the December 21, 2010 MRI because it had been previously scheduled, and was very surprised to find out that she had a complete ACL tear. She advised the panel of her conversations with her treating sports medicine specialist who indicated that she fit into a certain subgroup of people with complete ACL tears who were "copers," meaning that they were asymptomatic and highly functioning, even with an ACL deficiency.

Employer's Position

The worker's manager attended on behalf of the employer as a watching brief. The manager provided information regarding the accident. She indicated that she was present when the worker hurt herself at a workplace event supporting a local charity. The manager described the injury as being quite a dramatic event, and that the worker required considerable assistance immediately afterward. It was the manager's view that the mechanism of injury was severe enough to have caused an ACL tear.

Analysis

The issue before the panel is whether the worker is entitled to compensation for an ACL tear relating to the work-place accident on October 28, 2009. For the worker to be successful, the panel would have to find that the ACL tear also arose out of and in the course of the worker's employment, or more particularly here, from the mis-step that the worker had while doing a dance step on that day. After our review of all the evidence, the panel was able to make that finding. Our reasons follow.

The panel notes that the worker was formally diagnosed with a complete rupture of the ACL in her right knee while undergoing an MRI test in December 21,2010. This was an unexpected diagnosis, some 14 months after the October 28, 2009 event, and given that the MRI ordered a year earlier queried a possible meniscal tear in the worker's knee from the fall that she had taken, and not a possible ACL tear. The earlier adjudications on this file have also been confounded by relatively limited ACL-related findings and the extremely active year that the worker had while on vacation, apparently without her functioning being limited by what was later found to be a complete rupture of the ACL in her left knee.

Our analysis will thus turn to the following questions:

a. Could the mechanism of injury for the worker's October 2009 actually cause an ACL tear? In other words, anatomically plausible?

b. Do the examinations and medical findings between October 2009 and December 2010 support a causal connection between the December 2010 MRI findings and the compensable accident?

c. What role, if any, does the worker's active year-long vacation have in our consideration of the work-relatedness of the ACL tear?

Could the mechanism of injury for the worker's October 2009 actually cause an ACL tear? In other words, is this scenario anatomically plausible?

Regarding potential mechanisms of injury that might cause an ACL tear, the panel notes from the general medical literature that ACL injuries are most commonly associated with valgus and external rotation, hyperextension, deceleration, and rotational movements of the knee. Histories often describe low velocity deceleration or rotational injuries to the knee and while physical contact is certainly a factor in many ACL tears in a sports-related context, the medical literature suggests that, often, no physical contact is involved or required for such an injury to occur. Common first symptoms include giving way or buckling of the knee or an audible popping in the knee.

The panel notes that a WCB orthopaedic consultant suggests that the mechanism of injury is more consistent with the lateral collateral ligament strain that was first diagnosed and treated, and notes that general lack of positive Lachman's and anterior drawer tests to support the diagnosis.

At the hearing, the panel asked questions regarding the exact mechanism of injury but the worker acknowledged that she could not provide a lot of detail because of the passage of time. The worker's supervisor did indicate, however, that what had happened was quite sudden and obviously painful. The worker was in fact taken directly to the emergency department at a nearby Winnipeg hospital. The panel therefore has carefully examined the earliest information on the file for information regarding the mechanism of injury, and notes the following:

• On October 28, 2009, immediately after the incident, the worker provided the following history when she was taken to an emergency department at a Winnipeg hospital: "While dancing, bent right knee outward." On October 29, 2009, the day following the incident, the worker provided the following history to a triage nurse shortly after her arrival at a sports medicine clinic. She indicated "[illegible] dancing took steps forward planted R foot then twist into varus [with] pain lat knee…" and at another point in the report indicated "R knee buckled."
• When the worker contacted the WCB on November 2, 2009, she indicated, "I took a couple steps and hopped to a stop and my right knee gave out. I was on the carpet on the office."At the hearing, however, the panel carefully reviewed the mechanism of injury that led to the worker's fall on the dance floor, and finds that it is consistent with the potential development of an ACL tear, that is, that the awkward collapse or buckling caused by the "bad dance move" could have caused an ACL tear.
• At the hearing, the worker described the incident as follows: "I was dancing and going this direction with a really odd movement with my leg. I was stomping it out and then when I came to a quick stop I felt the knee buckle and go out…" which she later clarified that the odd movement was to the right and down. She did not fall down but had to stand there until the end of the song, when her supervisor and manager carried her off the performance area, placed her in a wheelchair and arranged for her to get to a hospital. The manager confirmed this description, adding that the worker was able to lean against the wall until the song had finished.

The panel finds on a balance of probabilities that the described mechanism of injury is consistent with the etiologies that are known to cause an ACL tear and conclude that the worker could have torn her ACL at work, that is, it is anatomically plausible that the ACL tear was work-related.

Do the examinations and medical findings between October 2009 and December 2010 support a causal connection between the December 2010 MRI findings and the compensable accident?

The panel notes that a WCB orthopaedic consultant reviewed the clinical findings and the mechanism of injury and suggests in a memo dated March 14, 2011 that "the MRI findings of a complete ACL tear was a surprise based on the reported mechanism of injury and subsequent clinical findings shortly after the workplace incident. A strain of the knee or partial tear of the LCL would be more in keeping with the described mechanism of injury."

The panel, however, finds that there are a number of indicators of a potential ACL problem in the early medical evidence to support the findings of an ACL tear that was discovered on the MRI of December 2010. In particular:

• The WCB orthopaedic consultant expressed concerns regarding the earliest symptoms as follows: "a greater force was required to cause an ACL complete tear than required to cause a partial tear of the LCL, so more immediate pain, swelling and disability would generally be experienced with an ACL tear." The panel notes that the worker had to be helped to a wheelchair, and was taken to a hospital emergency department because of immediate pain, swelling, and disability. By mid-November, the worker was still barely able to walk at the time she started physiotherapy.
• The worker saw a sports medicine specialist on November 2, 2009 who provided a diagnosis of a lateral collateral ligament strain. He also provided a differential diagnosis of a possible internal derangement of the knee, and ordered an MRI for that reason. This was the MRI that had been scheduled for December 2009 and later postponed to December 2010 to accommodate the worker's trip. The panel notes this differential diagnosis was provided quite early in the management of the file, suggesting that a pathology more significant than a simple strain was suspected within days of the original injury.
• The worker then saw a second sports medicine specialist on November 12, 2009 who later provided a narrative report dated November 16, 2011. He notes that the worker's original subjective complaints were "varus and pivot, felt lat [lateral] pop, lat [lateral] pain initially…" He performed two ACL-specific tests, and notes that "The Lachman test appeared negative. She had 1+ drawer." He further states that he agreed at that time with the earlier request for an MRI in order to rule out an internal derangement. The panel notes that this physician did report one positive and one negative test for an ACL problem in November 2011, approximately two weeks after the injury date.
• A narrative report from a physiotherapist dated November 24, 2011 notes the worker was first seen by a different physiotherapist at the clinic on November 13, 2009, and indicates that: "Upon chart review, she reported injuring her knee with a varus load while dancing on October 28, 2009. His impression at that time was that she injured her lateral collateral ligament, medial meniscus and possibly the anterior cruciate ligament." The panel notes this impression was approximately two weeks after the injury date.
• The worker participated in extensive physiotherapy prior to her next appointment with her sports medicine specialist who she saw on December 31, 2009, immediately prior to her trip. At the hearing, she described significant overall improvement in physiotherapy, from being barely able to walk to restoration to full activity. She was also fitted with a custom brace which she used infrequently. The specialist similarly notes in his narrative report regarding the December 31, 2009 visit that: ". …Her symptoms and function had improved substantially. …. Collateral ligament testing revealed mild laxity of her lateral collateral ligament. She had a 1+ drawer sign, which seemed equal to her left knee and McMurray’s was negative.” He then comments that: "Clinical examination of December 31, 2009, was consistent with healing of a lateral collateral ligament sprain. I advised her that I was still concerned about internal derangement and possible meniscal injury, bone bruise, or cruciate ligament injury which was documented in my clinical notes of December 31, 2009." The panel again notes a positive finding for one of the ACL tests and the ongoing medical concerns despite the worker's significant functional improvement.

The panel finds that the clinical tests by the worker's treating healthcare professionals did indicate strong suspicions for internal derangement of the knee including some ACL-specific tests that were positive prior to her departure on an extended vacation. These findings were made shortly after the injury date and as well after the successful completion of aggressive physiotherapy on her knee.

What role, if any, does the worker's active year-long vacation have in our consideration of the work-relatedness of the ACL tear?

The panel notes that the adjudication of this claim has been confounded by the worker's apparent ability to resume a high level of functioning for a one year period, and the first diagnosis being provided 14 months after the original injury, from the December 21, 2010 MRI. The panel, however, notes the following evidence on file that was more recently provided by the worker's advocate, prior to the hearing:

• The worker's treating sports medicine specialist in his narrative report dated November 16, 2011 provides general comments on treatment options for an ACL deficient knee: "The treatment for an ACL deficient knee can be conservative, or surgical. One third of patients do well with conservative treatment and are termed copers, in that they can function at a normal level with a damaged ACL. Two-thirds of patients decompensate, or have significant symptoms of instability and require surgical stabilization to improve their outcomes."
• As to his specific treatment of the worker, the specialist indicates that: "Initial clinical evidence was more concerning for a lateral collateral ligament injury, although internal derangement remained within the differential. Clinical evaluations did show some ACL laxity with anterior drawer testing, but seems similar to her other knee. It should be noted that ACL injuries are missed on clinical exam and that is one of the reasons we do MRI to further define internal derangement and pathology. She did extremely well clinically until she did get her MRI, which ultimately defined a torn anterior cruciate ligament. There was no evidence to support any new events that occurred in the interval during her time away and she was actually functioning at a very high level on clinical review on her return to Canada. Therefore, ongoing conservative treatment was recommended. She had an unfortunate event in February of 2011, where she decompensated and now requires ACL surgery."
• A third sports medicine specialist treated the worker in 2011 following a February 2011 incident when the worker's knee became clearly symptomatic. He reviewed the worker's file from that clinic and notes that "I understand from [the second sports medicine specialist's] note that [the worker] was clinically doing well with no further signs of instability involving her right knee. Despite an ACL tear, there is a subset of the population that do well with full ACL tears and at this point in time [late 2009], surgery would not have been indicated."
• The worker had a functional right knee and was asymptomatic at the time she had the right knee MRI performed in December 2010.