The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

An appeal panel hearing was held on February 21, 2006, at the request of the worker. The worker appeared and provided evidence. The accident employer did not attend. The panel discussed this appeal on February 21, 2006 and on July 12, 2006.

Issue

Whether or not the worker has recovered from the effects of his compensable injury.

Decision

That the worker has not recovered from the effects of his compensable injury.

Decision: Unanimous

Background

On May 16, 2005 the worker was working in a pig pen moving pigs when one pig weighing approximately 70 pounds hit the worker's right knee from the side causing injury. The worker contacted the Manitoba Workers Compensation Board (WCB) to report the injury. He also attended a local emergency room facility and his family physician.

The local emergency room facility report of May 16, 2005 noted a prior history of an anterior cruciate ligament (ACL) repair to his right knee 20 years before with recent problems for which he had seen an orthopaedic surgeon. An MRI done several days before revealed:

1. Severe impingement of ACL graft on roof of femoral intercondylar notch. ACL graft is thinned but remains intact.
2. No definite meniscal tear.
3. 5MM low signal nodule in posterior knee which may represent a loose body.
4. Chondromalacia medial patellar surface."

On examination, the emergency room physician noted slight swelling of the knee and slight laxity with valgus stress. The worker was diagnosed with a medial meniscal injury to his right knee and a medial collateral ligament (MCL) sprain. He was discharged with a leg splint and crutches with instructions to follow up with his orthopaedic surgeon. The worker was considered fit to perform modified duties.

The worker's family physician also diagnosed the worker with an MCL sprain and possible medial meniscus injury. It was his opinion that the worker's pre-existing arthritis in his right knee might affect recovery.

On May 26, 2005, the worker saw his treating orthopaedic surgeon. A May 27, 2005 report records this examination. The surgeon noted effusion and tenderness along the medial collateral ligament and tenderness along the medial joint line. Plain film x-rays revealed a previous ACL graft as well as some slight degenerative changes. The surgeon provided a diagnosis of right knee MCL tear and medial meniscus tear. Treatment recommendations included providing the worker with a Generation II brace, increasing range of motion and physiotherapy for strengthening.

Arthroscopic surgery was carried out on September 2, 2005. The operative report notes that the medial compartment revealed small medial meniscal tears which were trimmed using a shaver. Chondromalacia and loose bodies were not noted in the medial compartment. The previous ACL graft was then examined and was found to be completely loose with multiple strands torn off and floating. These were removed using the shaver. The lateral compartment of the knee was then examined and a ½ cm meniscal tear was noted. As it was not unstable, it was left alone. The post-operative diagnosis was ACL graft tear, chondromalacia of the lateral femoral condyle grade 2, and a medial meniscal tear.

The worker's file was reviewed by a WCB medical advisor on September 28, 2005. The medical advisor opined that the compensable accident likely only resulted in the meniscal tear injury. He did not think that the ACL tear was related to the compensable injury given the level of degeneration in it.

On September 29, 2005, the WCB advised the worker that it would no longer accept financial responsibility for his right knee claim. This position was upheld by Review Office in a decision dated October 28, 2005. In making this determination, Review Office sought the opinion of an orthopaedic consultant who echoed the finding that the workplace accident only caused a medial meniscal tear.

On November 21, 2005, the worker completed an application appealing the decision of Review Office to the Appeal Commission. An oral hearing was convened into this matter on February 21, 2006 subsequent to which the panel decided to obtain further medical information from the orthopaedic surgeon who performed the arthroscopic procedure in September 2005 and as well, from a second orthopaedic surgeon who assessed the worker in January 2006. The information from the two surgeons was received at the Appeal Commission and was shared with the interested parties. An opportunity was given to provide final comment. On July 12, 2006, the panel met again to further discuss this case.

Reasons

To accept the worker's appeal the panel must find that the workplace accident is responsible for the worker's ACL tear. We are able to make that finding.

The worker had a pre-existing ACL graft in his right knee. Just prior to the workplace accident the worker was experiencing some swelling but no instability.

The MRI done on May 12, 2005 revealed a thinned but intact ACL graft. This was not the case when the orthopaedic surgeon performed the arthroscopy. At that time, the ACL graft was completely loose and torn.

The worker described the mechanism of injury as a push from the outside of his right knee, forward and inward to the left, which caused him to fall. He has since suffered from instability in his knee.

The worker's orthopaedic surgeon opines that this type of mechanism of injury is consistent with both an ACL tear and a meniscal tear. When asked by the panel as to what the prognosis of the worker's right knee would have been had the May 16, 2005 accident not occurred, the orthopaedic surgeon responded:

"…Certainly the history of the mechanism of injury and physical exam are consistent with a tear of ACL graft. However, one should remember that perhaps 20 years of impingement of the graft against the roof of the femoral intercondylar notch could also produce an ACL looking like what I found at the time of arthroscopy.

In summary there will be no one able to tell whether he in fact tore his ACL at the time of his workplace injury or whether the findings at the time of knee arthroscopy, were only due to graft impingement. Certainly, both are possible, probably on a balance of probability of 50% each.

If the May 16, 2005 workplace accident did not occur, he probably would not have needed the surgery that was performed.

Please note, that he did come in with some hard findings of an acute injury to the knee. He had a gross effusion, indicating a new injury…

The likely prognosis, for the worker's knee. If the accident had not have occurred, would be a gradual deterioration of the condracartilage and progression towards a postermedial type of osteoarthritis of the tibial femoral joint. Perhaps requiring a total knee arthroplasty in the distant future…"

Given the worker's pre-existing knee condition, the mechanism of injury and his treating orthopaedic surgeon's opinion that surgery would not have been needed if the workplace accident did not occur, we find, on a balance of probabilities that the worker's right ACL condition was enhanced by the May 16, 2005 workplace accident.

The WCB considered the worker recovered from the effects of his compensable injury as of October 5, 2005 on the basis that he only suffered a medial meniscal tear. The worker nonetheless continued with treatment for his knee related to his ACL tear after that date. Given our finding that the worker's ACL condition was enhanced by the workplace injury, we correlatively find that he had not recovered from the effects of his compensable injury at that time.

Accordingly, the worker's appeal is granted.

Panel Members

L. Martin, Presiding Officer
A. Finkel, Commissioner
M. Day, Commissioner

Recording Secretary, B. Kosc

L. Martin - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 10th day of August, 2006