The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker is appealing the decision made by Review Office of the Workers Compensation Board ("WCB") that there was insufficient evidence to support that her right rotator cuff tear was related to the workplace accident of August 2, 2009. A hearing was held on December 17, 2013 to consider the matter.

Issue

Whether or not the worker is entitled to wage loss benefits beyond April 20, 2011.

Decision

That the worker is not entitled to wage loss benefits beyond April 20, 2011.

Decision: Unanimous

Background

During the course of her employment as a house supervisor on August 2, 2009, the worker was lifting a client from a sitting position when she suffered an injury to her right shoulder. The claim for compensation was accepted based on the initial diagnosis of a right rotator cuff strain and benefits and services were paid to the worker.

On October 22, 2009, a WCB medical advisor stated that the most likely diagnosis related to the reported mechanism of injury would be rotator cuff tendinopathy.

On November 18, 2009, the worker underwent an MRI of her right shoulder which showed the following findings:

The biceps tendon and glenoid labrum are normal. The glenohumeral joint is unremarkable. The acromion has a type 1 shape with a subacromial spur. The AC joint has minimal capsular overgrowth. The rotator cuff appears normal. There is minimal subacromial bursal fluid.

A WCB medical advisor reviewed the worker's file on December 2, 2009 and stated that the worker appeared to have a chronic strain/sprain of the shoulder based on the medical information dated November 3, 2009 which showed tenderness over the bicipital tendon with reduced range of motion in abduction and extension. There was very little evidence of a pre-existing condition other than the acromioclavicular ("AC") spur. He said the AC spur could contribute to symptoms of possible impingement syndrome.

Following a WCB call-in examination on December 16, 2009, the WCB medical advisor concluded that the worker had adhesive capsulitis of the right shoulder related to her compensable injury.

On December 19, 2009, a pain clinic specialist confirmed that the worker had adhesive capsulitis involving her right shoulder and a treatment plan was formed. The WCB authorized a course of right suprascapular nerve blocks followed by physiotherapy treatment.

On August 28, 2010, the pain clinic noted that the worker reported improved range of movement and pain level in her shoulder with the injections. Additional injections were authorized by the WCB.

On December 20, 2010, the worker was seen by a WCB medical advisor for assessment of her right shoulder condition. The medical advisor stated that his examination findings and the file information did not support the presence of a current right shoulder adhesive capsulitis to account for the worker's current presentation. The medical advisor stated:

The combination of i) a positive Speed's test, ii) negative Yergason's test, and iii) positive impingement tests at the right shoulder noted on today's examination suggest a right shoulder impingement process. However, the November 18, 2009 MRI report noted a normal-appearing right rotator cuff. As such, to the extent that the August 2, 2009 workplace accident involved a strain of the right rotator cuff tendon, the magnitude of same would likely have been in the mild category, given the normal imaging demonstrated 3 months post-injury. Mild rotator cuff strains are generally expected to resolve within 8-12 weeks of the injury. In so far as the complication of what was reported to have been an adhesive capsulitis has now resolved, and given that the overall nature of [the worker's] presentation is beyond that of a mild rotator cuff strain, this review is not able to account for [the worker's] overall symptomatology and reported impairment of right shoulder function in relation to the initial strain 16 months ago, on August 2, 2009, and consequent resolved capsulitis…An updated MRI of the right shoulder is recommended, to clarify if there has been a change in the status of [the worker's] rotator cuff that would account for her current presentation.

A repeat MRI of the right shoulder was performed on February 22, 2011. The report noted minor AC joint osteoarthritis but it was non-progressive since the prior study. There was a new finding of a near full thickness, articular-sided partial tear of the supraspinatus tendon involving the anterior-peripheral fibers. There was an associated small interstitial component. Maximum measured tear gap was 0.7 cm.

On March 8, 2011, a WCB medical advisor stated that the partial tear of the right supraspinatus accounted for the positive impingement signs elicited during the December 20, 2010 call-in examination. Given that the initial MRI performed 3 months after the date of injury demonstrated no supraspinatus pathology, the current diagnosis of a partial tear was not accounted for by the workplace injury sustained on August 2, 2009.

A WCB case manager noted to the file that the worker could not recall any specific incident that could account for the rotator cuff tear and the worker suggested that the tear could be the result of physiotherapy treatments following the supraspinatus nerve blocks. The worker later suggested that the rotator cuff tear had been present since the date of her compensable injury as her right shoulder symptoms had remained the same since the initial injury.

In a note to file dated March 10, 2011, a WCB physiotherapy consultant opined that it was not likely that the physiotherapy treatment provided to the worker resulted in the right shoulder supraspinatus tear as reported in the February 22, 2011 MRI report.

On April 15, 2011, the WCB case manager determined that based on the accident description, diagnosis, treatment rendered, treatment duration and current medical findings, the worker had recovered from the effects of the August 2, 2009 workplace injury and any ongoing shoulder difficulties were not related to her compensable injury.

In May 2011, the worker provided the WCB with a report from an orthopaedic consultant dated April 12, 2011 to support that the partial tear of the supraspinatus tendon came about from the lifting incident at work.

On May 5, 2011, a WCB sports medicine consultant outlined his opinion that there was no temporal relationship between the new diagnosis of a tear and the August 2, 2009 workplace injury.

On May 11, 2011, the WCB case manager determined that based on the WCB medical opinion of May 5, 2011, no change would be made to his April 15, 2011 decision.

On July 5, 2011, the worker underwent right shoulder surgery. The post-operative diagnosis was rotator cuff disease and AC joint arthritis of the right shoulder.

Based on an appeal submitted by the worker, Review Office sought medical advice from a WCB orthopaedic consultant with respect to the worker's right shoulder condition. On July 13, 2011, the WCB orthopaedic consultant stated:

1. The diagnosis of the workplace injury was probably a rotator cuff strain. Had there been a cuff tear it is more likely than not that it would have been demonstrated on MRI on 18-Nov-2009.

2. The diagnostic clinical criteria for adhesive capsulitis (frozen shoulder) are not a subject of general consensus. As a result of the workplace injury, there may have been an element of adhesive capsulitis with gradual recovery of range of motion over a year or so. Alternatively, the reduced ROM may have been related to a combination of the rotator cuff strain and a slowly developing degenerative tear of the rotator cuff.

3. The partial thickness tear of the rotator cuff demonstrated on MRI of 20-Feb-2011 (sic) must have developed in the time interval between 18-Nov-2009 and 20-Feb-2011 as there is a low probability that it was missed in the first MRI. There is no objective evidence that the partial thickness tear was caused by WCB-sponsored treatment of the right shoulder.

4. I have reviewed the discs of the two MRI's (sic) have compared them directly. I agree with the radiology reports that there was no tear visible on the MRI of 18-Nov-2009.

On July 20, 2011, Review Office determined that there was insufficient evidence to support that the worker sustained a rotator cuff tear as a result of the workplace accident on August 2, 2009 or as a result of any treatment she received from her right shoulder injury. Review Office felt there was no evidence on file to support a causal relationship between the worker's current difficulties and the August 29, 2009 compensable injury.

By letter dated January 6, 2012, the treating orthopaedic surgeon opined that: "The working diagnoses of the August 2, 2009 work-related injuries were rotator cuff tearing and acromioclavicular joint injury" and "In view of the historical continuity in symptoms from the time of the injury to the time of surgery, the relationship is rotator cuff injury following work injury." He stated that: "I would tend to disagree with the WCB opinion that this patient had a normal cuff in 2009 and then just wore it out and tore it over the next year and a half, particularly during the period of reduced use and reduced mobility and function with documentation of associated stiffness and/or adhesive capsulitis ongoing."

In an opinion dated February 22, 2012, the WCB orthopaedic consultant indicated:

I understand the opinion of [treating orthopaedic surgeon] to be based on:

(a) The continuity of symptoms following the workplace injury.

(b) The probability that there was a false negative first MRI.

(c) The low probability that the tear occurred during a period of low level use of the shoulder.

(d) That the second MRI was not consistent with the subsequent arthroscopy findings.

The WCB orthopaedic consultant's response was that:

(a) I agree that symptoms have continued. It is probable that rotator cuff strain would cause symptoms resembling those of a rotator cuff tear, and differentiation would normally be by imaging study of MRI.

(b) MRI is reported in medical literature to be a very sensitive and specific means of diagnosing rotator cuff tears in the shoulder …

(c) There is a significant degenerative factor in development of rotator cuff tears, and tears often occur in shoulders with low level activity. In geriatric age ranges, most people have defects in their rotator cuffs.

(d) The second MRI was reported as showing an almost full thickness tear mainly on the articular side. Arthroscopy findings were of an almost full thickness tear mainly on the bursal side. The correlation was limited to a finding of an almost full thickness tear. Had there been such a tear at the time of the first MRI, it is very probable that it would have been observed and reported.

On balance of probabilities, the tear of the rotator cuff was not caused by the workplace injury.

The worker requested a Medical Review Panel ("MRP") pursuant to subsection 67(4) of The Workers Compensation Act (the "Act") based on the position that a difference of medical opinion existed between the WCB medical advisor and her physician on a medical matter that was affecting her entitlement to benefits. The request for an MRP was granted by the Appeal Commission under Decision No. 122/12. Although efforts were made to arrange an MRP, significant delay was encountered and an MRP was not co-ordinated. On October 2, 2013, the worker withdrew her request for an MRP.

On October 2, 2013, the worker filed an appeal with the Appeal Commission with respect to Review Office's decision of July 20, 2011 and a hearing was convened.

Reasons

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(1) of the Act provides that wage loss benefits will be paid: “…where an injury to a worker results in a loss of earning capacity…” 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 ends, or the worker attains the age of 65 years.

Worker's position:

The worker appeared at the hearing accompanied by a worker advisor. The worker's position was that the medical evidence supported that she continued to suffer from the effects of her compensable right shoulder injury beyond April 20, 2011. It was submitted that the finding of a partial supraspinatus tear and impingement of the right shoulder was related to the workplace accident of August 2, 2009. The treating orthopaedic surgeon provided an opinion which stated that in view of the historical continuity of symptoms from the time of the injury to the surgery, the August 2, 2009 work-related injuries were rotator cuff tendon tearing and an acromioclavicular joint injury. The medical evidence supported that the injury was more than a strain and therefore, there should be entitlement to further wage loss benefits.

With respect to the MRI of November 18, 2009 which did not identify a tear, it was submitted that the test was a false negative. There was sufficient confirmation from the medical reports leading up to the MRI of November 18 and after which supported a specific rotator cuff tendon as a pain generator. It was noted that medical literature relied upon by the WCB orthopaedic consultant regarding the sensitivity of MRI imaging referred to 3.0T MRIs; however the worker's MRI was performed using a 1.5T level. Further, the worker's evidence was that the manner in which her arm was positioned for her two MRIs differed and this could account for why a partial tear was detected on the second MRI but not on the first.

Overall, it was submitted that a continued relationship was supported by the medical reports on file and that there was further entitlement to compensation beyond April 20, 2011.

Analysis:

The issue before the panel is whether or not the worker is entitled to wage loss benefits beyond April 20, 2011. In order for the worker's appeal to succeed, the panel must find that the injury to the worker's right shoulder on August 2, 2009 was more serious than a strain injury and either caused or contributed to a tear of the right rotator cuff. On a balance of probabilities, we are not able to make that finding.

The largest factor weighing against the worker's claim is the November 18, 2009 MRI which indicated that the worker's right shoulder had a normal rotator cuff. This would suggest that the tear which was surgically repaired in July 2011 was not caused by the August 2009 incident.

The panel acknowledges that MRI imaging does not always accurately identify all conditions present in a person's anatomy and it is certainly possible for an MRI to report a false negative. However, in order for the panel to place less weight on the MRI report, there would have to be sufficient evidence of specific rotator cuff tear symptoms and/or positive clinical testing to cause the MRI findings to come into doubt. We find that there is not. A careful review of the medical findings during the initial period following the August 2009 workplace accident would suggest that a rotator cuff tear was not present. In particular, the panel notes the following:

• In August 2009, the worker was examined by both a chiropractor and a physiotherapist. Neither medical practitioner suggested or queried a diagnosis of rotator cuff tear. Both indicated a sprain/strain type injury;
• No impingement findings were identified;
• A subsequent report dated April 6, 2010 from a physiotherapist indicated: "Remainder of upper limb ROM (range of movement) full all mov'ts but painful; strength 5/5 … ROM and strength needed lots of encouragement to do fully due to pain; no painful arc."
• In response to treatment at a Pain Clinic in the Spring of 2010, both the medical director and the treating physiotherapist reported improvement in range of motion. This would suggest that a condition other than a supraspinatus tear was responsible for the worker's pain and limitations at that time, as improvement in range of movement would not be expected if a tear was the source of the problem.

Importantly, the WCB orthopaedic consultant noted that the tear was an almost full thickness tear and stated that had there been such a tear at the time of the first MRI, it was very probable that it would have been observed and reported. The panel feels that while the sensitivity of an MRI may be questioned in some cases where the injury is more subtle, in this case the tear was significant and not likely to have been missed on MRI. This is despite the fact that the MRI level was 1.5T and the positioning of the worker's arm differed. We accept the opinion of the WCB orthopaedic consultant, particularly given that he reviewed the discs of the two MRIs and compared them directly.

Overall, this was not an easy case to decide and the panel acknowledges the frustrations the worker encountered in gathering medical information. Unfortunately, the evidence on file is such that we are not satisfied on a balance of probabilities that the supraspinatus tear was sustained on August 2, 2009. We therefore must find that the worker is not entitled to wage loss benefits beyond April 20, 2011. The worker's appeal is dismissed.

Panel Members

L. Choy, Presiding Officer
A. Finkel, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kosc

L. Choy - Presiding Officer

Signed at Winnipeg this 4th day of February, 2014