The employer and insurer appeal from the compensation judge’s finding that there is a causal connection between the employee’s current left rotator cuff condition and her March 20, 2007, work-related injury, and also appeal from the award of the expenses related to the employee’s left rotator cuff surgery and from the denial of the petition to discontinue workers’ compensation benefits.  We affirm.

Patricia L. George began working for Velocimed, a manufacturer of heart catheters and the predecessor company to St. Jude Medical, Inc., on June 16, 2004.  Within the next three years, St. Jude Medical, the employer, purchased Velocimed, and Ms. George, the employee, continued to work for the employer.  She initially was hired to work as an assembler on a process line, where she made medical devices; her primary duties included assembling and inspecting catheters.  She worked in that position for more than two years and, by September 2006, she was promoted to the position of a team lead, in the “silicone room.”  Following this promotion, the employee was responsible for assembling inflation cases, devices that are attached to cardiac catheters for inflating and deflating catheter balloons.

The employee claims that she injured her left shoulder as a result of the assembly work she performed in the employer’s silicone room.  On or about March 20, 2007, the employee began to notice pain in her left thumb and arm; that pain eventually extended into her left shoulder.  On March 23, 2007, she sought medical care at the Fairview Northland Clinic in Elk River, where she was evaluated by Mr. Martin Langenfeld, a physician assistant.  The employee described her symptoms as a “frozen shoulder;” she reported to Mr. Langenfeld that her pain had started in her left hand and then radiated to her left shoulder, and that grasping caused her pain and awakened her from sleeping.  Mr. Langenfeld diagnosed the following:  a radial styloid tenosynovitis; deltoid, supraspinatus and biceps tendinitis; and a sprained acromioclavicular joint.  He prescribed rest and use of a thumb spica splint and arm sling at the employee’s discretion.  Mr. Langenfeld released the employee to return to work within restrictions of limited repetitive motion of the left hand and shoulder, and no overhead lifting or reaching.  The employee evidently attempted a return to work, but shortly thereafter was unable to continue working due to her symptoms.  The employer and insurer initially admitted primary liability for the employee’s claimed injury, and commenced payment of temporary total disability benefits.  The employee remained off work for approximately two months, and returned to work on a light-duty basis in late May 2007.

A crucial aspect of this litigation is the nature of and description of the employee’s job duties in March 2007.  The employee’s job duties as a lead person in the silicone room included assembly work as well as ordering and handling inventory, printing work orders, and setting up product labels; she typically worked with one other employee in the silicone room.  Her primary duties rotated between the assembly of Toughy valves^[1] or catheters, and the assembly of an inflation case for attachment to a cardiac catheter, all which required detailed work and fine manipulation.  To assemble the inflation case, the employee held a catheter in one hand and another part in the opposite hand, pushing the two parts together and then turning the threaded portion of the parts until they clicked together.  The employee testified that she applied considerable force with her left arm while pushing the parts together, to stabilize the parts in a level position in order to prevent any kinks from developing in the catheter tube.  At times she performed this assembly with her arms extended out in front of her, and at other times she rested her forearms on the table in front of her, depending on which part she was working with at the time.  The employee testified that she and the other employee in the silicone room occasionally performed this particular task as many as 90 times per day, although typically would perform the task 37 to 75 times per day.  It was following the assembly of these inflation cases that the employee noticed pain extending from her left thumb into her arm and shoulder.

The employer contended that the employee exaggerated the number of times daily that she performed this Toughy valve assembly.  According to Todd Turgeon, the employee’s immediate supervisor at the time of her injury on March 20, 2007, the employee may have assembled an average of 40 devices each day.  He testified that only on very rare occasions would the employee or other employees have assembled more devices per day, for example, the 90-per-day amount cited by the employee.  He based his testimony in part on the itemized manufacturing processes descriptions submitted into evidence.

Jeff Mahoney, a former manufacturing engineer for the employer, testified by deposition.  He worked as a manufacturing supervisor from May 2005 until August 2006 and supervised the employee during that time period.  Between August 2006 and October 2007, Mr. Mahoney worked for the employer as a manufacturing engineer.  He recalled that the employee had reported pain in her left shoulder, and that once he and others recognized this as a manufacturing issue, they tried to eliminate all compressive forces that were within the employee’s work process, for example, the snapping together of the valve parts.

Following her injury, and on referral from Mr. Langenfeld, the employee received physical therapy in April and May 2007 at the Institute of Athletic Medicine.  According to the employee, her frozen shoulder condition ultimately resolved after completion of her physical therapy program.  She returned to work on May 24, 2007, working two days per week, attempting to rotate her duties and tasks.  In August 2007, the employee increased her work schedule to include three non-consecutive days per week.  Although her left shoulder symptoms improved slightly during the summer of 2007, the employee still experienced pain in her left shoulder and found that her ability to use her left shoulder to reach or lift overhead was limited and that her left shoulder pain increased while she worked.  Ultimately, due to her left arm pain, the employee discontinued work in mid-September 2007 and has not returned to work in any capacity since then.

Mr. Langenfeld referred the employee for an MRI scan of the left shoulder to assess the cause of this increase in her pain, and also referred her to an orthopedist for an evaluation; the scan, taken on October 1, 2007, detected a small full thickness supraspinatus rotator cuff tear.  On October 11, 2007, the employee consulted Dr. David Edwards, orthopedist, reporting to him that her left shoulder had been bothering her since March 2007.  She reported no specific injury but felt that her left shoulder pain was related to her repetitive work.  According to Dr. Edwards’s chart note, the employee stated that her frozen shoulder had resolved but she still noted pain in the deltoid area of the supralateral shoulder, pain reaching out and up or even reaching back, and some discomfort in her left shoulder even while her arm was at rest.  During his examination, Dr. Edwards detected full right and left shoulder range of motion with the exception of slight limitation in the internal rotation on the left, compared to her right internal rotation.  He also noted some weakness in the employee’s left shoulder, but noticed no obvious atrophy on the left side compared to her right upper extremity.  Dr. Edwards diagnosed “symptomatic rotator cuff tear left shoulder,” and advised that, in his opinion, the employee was a good candidate for rotator cuff repair.

At the same time that the employee was undergoing medical evaluations and treatment, the employer and insurer arranged for an analysis of the employee’s job duties and job site.  On October 3, 2007, Mark Netzinger, physical therapist with American Ergonomics, Inc., conducted a job site analysis of the employer’s lead assembler position.  In his report of October 15, 2007, entitled “Worksite Ergonomic Evaluation,” Mr. Netzinger outlined the critical functions of the assembler position, as well as the physical demands and various physical requirements of the position.

On December 6, 2007, Dr. Paul Wicklund, orthopedic surgeon, conducted an independent medical examination of the employee on behalf of the employer and insurer.  At that time, the employee complained of ongoing pain in her left shoulder, with tenderness over the deltoid muscle.  She also reported pain radiating into her left arm and some pain at the IP joint of her left thumb.  Dr. Wicklund conducted a physical examination of the employee, and noted pain on palpation of the left AC joint and rotator cuff area; tenderness over the left deltoid, rotator cuff and supraspinatus tendon; and pain on impingement testing and at the AC joint.  Dr. Wicklund diagnosed a left rotator cuff tear, with chronic left shoulder pain.

In his report dated December 18, 2007, Dr. Wicklund outlined his opinion that the  work the employee had performed on a repetitive basis resulted in a small left rotator cuff tear.  He stated that,

In a supplemental report issued January 16, 2008, prepared after he reviewed the job description outlined in Mr. Netzinger’s job site analysis report, Dr. Wicklund revised his opinion on the causation of the employee’s left shoulder injury.  Dr. Wicklund qualified his opinion, and explained that his causation opinion depended on which job description was deemed to be accurate.  He stated as follows:

On April 22, 2008, the employee filed a claim petition requesting payment of medical expenses related to left shoulder surgery.  On June 25, 2008, the employer and insurer filed a petition to discontinue payment of workers’ compensation benefits, contending that there was no causal relationship between the employee’s March 20, 2007, work injury and her left shoulder condition.

On July 14, 2008, John Hovde, physical therapist with Saunders Physical Therapy,  conducted a job site analysis at the employer’s facility.  During his evaluation, Mr. Hovde prepared a video recording of the work stations and the assembly tasks.  He also prepared a written report following his evaluation, in which he explained that he had been asked to clarify the physical demands of the lead assembly position, and to focus on the tasks required for assembly of a Toughy valve, including assembly and packaging of the valve, and stocking and preparing an inventory of related parts.  Mr. Hovde also explained that the purpose of the job site evaluation was to address the discrepancies between the employee’s deposition testimony and the October 2007 work site ergonomic evaluation report submitted by Mr. Netzinger.

Mr. Hovde’s detailed report outlines his assessment of the type of movement and force required to perform various tasks and the frequency with which certain tasks were performed.  He concluded that the lead assembly job required “a lot of fine manipulation with the fingertips,” that the job included frequently pinching, grasping, manipulating and handling objects, that the job was neither fast nor highly repetitive, and that the part of the job spent assembling parts at a worktable was “sedentary.”  When asked whether the job required any unusual use of the shoulder, he responded that “every time you do anything with your hand, the shoulder muscles are somewhat active.  But there’s nothing I would call strenuous or unusual. . . . No more than desk work.”  In the course of his job site analysis, Mr. Hovde performed the valve assembly task.  He described the force required to snap together the valve parts as “light moderate,” similar to “snapping clothes together, like snapping an aspirin lid on, like punctur[ing] the hole in the seal of a tube.”

All claims were consolidated for hearing held on July 29, 2008.  Documentary and testimonial evidence was submitted into the record to illustrate the employee’s job duties, including a report from the job site analysis conducted by Mr. Netzinger in October 2007; a report and DVD recording of the job analysis conducted by Mr. Hovde in July 2008 as well as testimony by Mr. Hovde; and testimony presented by the employee; by Mr. Turgeon, the employee’s immediate supervisor at the time of her injury on March 20, 2007; and by Mr. Mahoney, a former manufacturing engineer, who had supervised the employee in 2005 and 2006.  Documents and items submitted into evidence included medical records, rehabilitation records, and the St. Jude Medical manufacturing process information.

In addition, testimony was also presented by deposition from Dr. Edwards, the employee’s consulting surgeon, and Dr. Wicklund, independent medical examiner.  Dr. Edwards testified that, in his opinion, the employee’s work activities represented a substantial contributing cause of her left shoulder condition and rotator cuff tear.  He also agreed, however, that the job demonstrated in the video recording did not look “particularly demanding,” and that if that video provided an accurate depiction of the employee’s job, he would not consider those activities to have caused a rotator cuff tear.  Dr. Wicklund’s testimony was consistent with that latter opinion by Dr. Edwards.  Based upon his review of the video recording of the employee’s job site, which seemingly contradicted the employee’s description of the tasks she performed in March 2007, Dr. Wicklund found no causal connection between the employee’s work and her left rotator cuff tear.  He also testified that he considered the employee’s earlier “frozen shoulder,” which had since resolved, had been idiopathic in nature.

In findings and order served and filed August 15, 2008, the compensation judge concluded that there was a causal connection between the employee’s current rotator cuff condition and her March 20, 2007, work injury.^[4]  The compensation judge found that the employee sustained a Gillette^[5] injury on March 20, 2007, in the nature of a left rotator cuff tear, that this injury rose out of and in the course of her work activity for the employer, and that there was a causal connection between the employee’s current rotator cuff condition and her need for surgery and current disability.

The employer and its insurer appeal from the compensation judge’s finding that there was a causal connection between the employee’s left rotator cuff condition and her work activities, asserting that substantial evidence does not support the compensation judge’s finding that the employee sustained a work-related left shoulder injury.  They also appeal from the related award of the expenses related to the proposed left rotator cuff surgery and from the compensation judge’s denial of their petition to discontinue workers’ compensation benefits.

A Gillette injury is an injury resulting from repeated trauma or aggravation of a preexisting medical condition.  Such a condition becomes compensable when the cumulative effect is sufficiently serious to disable an employee from further work.  Gillette v. Harold, Inc., 257 Minn. 313, 321-22, 101 N.W.2d 200, 205-06, 21 W.C.D. 105, 111-13 (1960); Carlson v. Flour City Brush Co., 305 N.W.2d 347, 350, 33 W.C.D. 594, 598 (Minn. 1981).  Questions of causation fall within the province of the compensation judge.  Felton v. Anton Chevrolet, 513 N.W.2d 457, 50 W.C.D. 181 (Minn. 1994).  A finding as to a Gillette injury is primarily dependent on the medical evidence.  See Marose v. Maislin Transp., 413 N.W.2d 507, 40 W.C.D. 175 (Minn. 1987).

In this case, the compensation judge reviewed the medical opinions and records, as well as the employee’s testimony and the testimony of other witnesses, and concluded that there was a causal relationship between the employee’s work activity and her left shoulder condition.  The compensation judge relied upon the temporal relationship between the appearance of the employee’s left shoulder symptoms and her work activity, the persistence and consistency of her left shoulder symptoms from the date of their onset until the MRI confirmed the rotator cuff tear, and that the employee’s work involved frequent to continuous use of her hands which, in turn, continuously engaged her shoulders.  The judge noted that the employee’s actual shoulder engagement was not as active as initially assumed by the doctors and as described by the employee, but that it was active, relying on the employee’s testimony when reaching these conclusions.

The compensation judge rejected the portion of the opinions of both the employee’s treating surgeon and the independent medical examiner that reflected a causal relationship between the employee’s job and her shoulder injury.  Both doctors had provided alternative causation opinions, that is, both concluded that if the employee’s job activities were as described by her, then such activities could have led to a left shoulder injury, or, alternatively, if the job site analyses were accurate, the light nature of the duties would not have led to a shoulder injury.  The judge rejected the former opinions, explaining that she did so because the description of the work activity both doctors were asked to assume was inconsistent with her own interpretation of the nature of that work activity.  Yet she found a causal connection between the employee’s work and her shoulder injury, based on other evidence.

The employer and insurer rely on the portions of the doctors’ opinions that reflected no causal relationship between the employee’s work and her shoulder injury.  They contend that the compensation judge ignored the unopposed expert medical testimony with respect to the actual mechanism of performance of the employee’s job duties and also ignored the expert medical opinions and testimony that the job performance demonstrated on the video would not cause a particular strain on the employee’s rotator cuff.  “[T]here is a difference between disregarding unopposed medical opinion and rejecting it on the basis of other evidence.”  Clark v. Archer Daniels Midland, slip op. at 6 (W.C.C.A. Feb. 14, 1994).  The compensation judge found that the portions of the doctors’ opinions supporting causation lacked adequate foundation and did not rely on those opinions in making her decision.  She relied on other evidence in the record, which, upon review, we conclude provided adequate support for the judge’s conclusions on causation.

The employer and insurer also argue that the compensation judge disregarded the results of the on-site job analyses.  They argue that those analyses showed that the employee’s job was not highly repetitive, that it did not require a significant amount of shoulder movement, and that there was nothing unusual or unique about the employee’s work duties that would have caused injury to her shoulder.  The employee disputed the accuracy of Mr. Netzinger’s evaluation, contending that he analyzed the duties of a revised job and did not consider the tasks required of the employee’s job as it existed at the time of her injury.  The employee also argues that Mr. Hovde’s opinion should not be regarded as persuasive, as he did not speak to the employee or her QRC concerning the employee’s job duties, nor did he speak to anyone who had performed the employee’s job as it existed in March 2007, but instead observed a demonstration of the job duties performed by a production employee who had not performed the employee’s duties in March 2007.  The employee contends, and Mr. Hovde testified, that he instead conducted his job site analysis based on what was suggested to him as to how the employee may have performed her job.

The compensation judge found evidence other than medical opinions and job site analyses on which to base her conclusion that there was a causal relationship between the employee’s work and her shoulder condition.  While a finding as to a Gillette injury is primarily dependent on the medical evidence, medical opinion is not the only form of medical evidence.  Medical records may also be considered as medical evidence and may be reinforced by an employee’s testimony.  Butler v. Metro Sheet Metal, 61 W.C.D. 177 (W.C.C.A. 2001), summarily aff’d (Minn. Apr. 25, 2001).  A compensation judge may base his or her conclusions on other reliable evidence in the record.  See Reimer v. Minnit Tool/M.I.T. Tool Corp., 520 N.W.2d 397, 51 W.C.D. 153 (Minn. 1994).  In addition, a compensation judge is not obligated to accept even unopposed medical testimony, since the issue of a Gillette injury is not within the exclusive province of the medical profession.  Leyhe v. Midland Constr., slip op. (W.C.C.A. May 8, 1996); Puchtel v. Twin City Bottle, slip op. (W.C.C.A. Sept. 21, 1993).

The employer and insurer argue that the employee’s testimony does not support any connection between the employee’s left shoulder condition and her work.  They rely on her initial history provided to Mr. Langenfeld, her treating physician assistant, and her later testimony, that her shoulder symptoms did not develop until approximately three days after she first noticed symptoms in her left arm.  They also rely on her testimony that her shoulder symptoms largely improved after physical therapy, testimony which they contend refutes the conclusion that the employee’s shoulder symptoms persisted from the date of onset until the MRI scan confirmed a rotator cuff tear.  The employee also testified, however, that her symptoms worsened in mid-September when she increased her work to three days per week; her medical records reflect that increase in her symptoms and her subsequent MRI scan and consultation with Dr. Edwards in October 2007.  The compensation judge found the employee to be credible, and it is not the role of this court to make an evaluation of the credibility and probative value of the witness testimony.  Redgate v. Sroga’s Standard Serv., 421 N.W.2d 729, 734, 40 W.C.D. 948, 957 (Minn. 1988).  The compensation judge relied upon the employee’s medical records and her testimony and concluded that the “repetitive, albeit low level, stress placed on the employee’s left shoulder by the demands of her work offers the most likely explanation for her left rotator cuff tear.”

Based on our review of the detailed records in evidence, and the testimony presented by the witnesses, we conclude that the record supports the compensation judge’s findings.  We are mindful that there is evidence in the record that supports the arguments presented by the employer and insurer.  The record also contains evidence to the contrary.  The issue under this court’s standard of review is not whether the facts will support findings different from those made by the compensation judge, but, rather, whether substantial evidence supports the findings of the judge.  Land v. Washington County Sheriff’s Dep’t, slip op. (W.C.C.A. Dec. 23, 2003) (citations omitted).  The employee’s medical records as a whole reasonably indicate that the employee sustained a work-related left rotator cuff tear, and those records are reinforced by the employee’s testimony.  We conclude that substantial evidence supports the compensation judge’s findings that on March 20, 2007, the employee sustained a Gillette injury in the nature of a left rotator cuff tear as a result of her work for the employer, and that there is a causal connection between that injury and the employee’s current left shoulder condition and need for surgery.  We therefore affirm the compensation judge’s findings and related orders.