The employer and insurer appeal the compensation judge’s findings that the employee sustained personal injuries arising out of his employment on November 19 and November 20, 2011, and that those injuries were substantial contributing causes of his left shoulder condition.  We affirm.

Ernesto Larrave, the employee, began working for William Radzwill, doing business as Aggregate and Bulk Carriers, the employer, in mid-2011.  The employee performed general farm labor at the employer’s ranch in South Haven, Minnesota, and other tasks as assigned by Mr. Radzwill.

On Saturday, November 19, 2011, the employee was directed by the employer to clean out a vacant building in a strip mall in Buffalo, Minnesota.  The previous tenant left items in the space including cans of paint, furniture, and two locked safes.  Mr. Radzwill was present with the employee at the Buffalo site for a short time, but then left the employee to clean out the vacant space with the help of a co-employee, Nelly.  The employee testified that he and Nelly were attempting to place a 400-pound safe on a dolly.  As the employee tilted the safe to place it on the dolly, he testified he felt an immediate sharp pain and a popping sensation in his left shoulder.  The employee stated he went home following this incident. 

Mr. Radzwill returned to the strip mall, picked up Nelly, and drove her home.  Mr. Radzwill testified that Nelly did not tell him that the employee had injured himself, nor did he hear from the employee that day.

The following day, Sunday, November 20, 2011, the employee reported to work at the employer’s South Haven farm.  The employee testified he then told Mr. Radzwill that he was going to leave work early because of left shoulder pain.  The employee stated he spent some time cleaning tools and then closed a large sliding door to a warehouse using his left arm.  He testified that as he did so, he experienced an acute reoccurrence of his left shoulder pain.

Mr. Radzwill testified that he arrived at the South Haven farm before the employee that Sunday.  When the employee arrived, the two worked together for approximately an hour and a half feeding and watering animals on the farm.  Mr. Radzwill testified the employee did most of the work, which involved carrying a two-gallon bucket of feed and filling water tanks.  Mr. Radzwill then directed the employee to clean tools in the work shed.  Mr. Radzwill then left for approximately 45 minutes, and when he returned, the employee was gone and the work shed was locked.  Mr. Radzwill testified that while they worked together that day, the employee made no mention of any left shoulder injury or problems.

On November 21, 2011, the employee saw Dr. Robert T. Mullaney at the Allina Medical Clinic in Buffalo, Minnesota.  The employee told the doctor that he was doing heavy lifting at work two days ago and felt a pop in his left shoulder and yesterday pulled a large gate open and felt a pop and since had had terrible shoulder pain.  On examination, Dr. Mullaney noted limited elevation and severely limited internal rotation of the left arm.  The doctor diagnosed a rotator cuff or brachioradialis tear, prescribed Vicodin, and referred the employee for an orthopedic evaluation.

The employee testified he attempted to reach Mr. Radzwill by telephone to discuss his injuries, but was unable to do so.  On November 23, 2011, the employee spoke with Mr. Radzwill and advised him that he had injured his shoulder at work.  Mr. Radzwill then sent an e-mail to his insurance carrier.

On November 24, 2011, the employee was seen at the Buffalo Hospital emergency room complaining of throbbing pain in his left shoulder which prevented him from sleeping.  The employee again gave a history of moving the safe and pulling the warehouse door closed with his left arm.  The doctor diagnosed a left shoulder sprain with a possible rotator cuff tear.

On December 8, 2011, the employee saw Dr. Dana Harms for an orthopedic consultation.  The doctor ordered an MRI scan which showed evidence of mild subscapularis and supraspinatus tendinopathy and moderate shoulder joint effusion with at least two loose bodies identified within the subcoracoid recess.  Thereafter, Dr. Harms administered two steroid injections into the employee’s left shoulder.

The employee was examined by Dr. Paul T. Wicklund on February 22, 2012, at the request of the employer and insurer.  The doctor diagnosed symptom magnification and mild rotator cuff tendonitis of the left shoulder with two loose bodies.  Dr. Wicklund opined that the activities of pulling on a safe and pulling on a door would not have caused either the loose bodies in his left shoulder or the mild tendonitis.  Rather, Dr. Wicklund opined these were pre-existing problems.  The doctor stated he found no evidence on the MRI scan for any acute injury to the employee’s left shoulder.  Dr. Wicklund opined the employee exhibited an exaggerated pain response which further treatment or surgery would not improve.  The doctor concluded there was no objective evidence for any further treatment or restrictions on the employee’s work activities.

By report dated March 8, 2012, Dr. Mullaney stated that the employee’s “shoulder injury was sustained at work.  His treatment by specialist, including a planned surgical procedure, is necessary and appropriate.”  (Pet. Ex. E.)  On March 13, 2012, Dr. Harms performed a left shoulder arthroscopy including a SLAP lesion repair, loose body removal, decompression, acromioclavicular (AC) resection, and distal clavicle resection.  By report dated March 15, 2012, Dr. Harms opined the employee injured his shoulder on November 19, 2011, while moving a large, heavy object, and reinjured it the next day pulling on a pole barn door at work.  Dr. Harms’ diagnosis was significant articular shoulder damage and a labral tear.

Dr. Wicklund was provided with and reviewed the surgical report of Dr. Harms and her March 15, 2012, medical report.  In a supplemental medical report dated April 11, 2012, the doctor again opined the employee’s shoulder problems did not result from his work activities on November 19 or November 20, 2011.  Rather, the doctor stated the employee’s articular cartilage loss, impingement and acromioclavicular joint arthritis were long-standing age-related problems.  Dr. Wicklund stated the employee did not sustain any forcible external or internal rotation of his left shoulder which would have caused a SLAP lesion.  Accordingly, Dr. Wicklund concluded that none of the findings seen in the March 13, 2012, surgery were related to the alleged left shoulder injury in November 2011.

The employer and insurer first contend the compensation judge’s factual findings are insufficient to permit adequate appellate review.  The appellants argue that the judge’s findings fail to weigh the evidence, are silent as to the medical evidence and opinions, lack any finding as to credibility and require inference and speculation to determine whether all contested issues were resolved.  Accordingly, the appellants contend the findings should be vacated and remanded to the compensation judge for further findings.  We disagree.

“The compensation judge’s decision shall include a determination of all contested issues of fact and law.”  Minn. Stat. § 176.371.  A judge must scrupulously ensure the findings of fact are sufficiently detailed and specific to enable a meaningful appellate review.  Northwest Publ’ns, Inc. v. Anderson, 259 N.W.2d 254 (Minn. 1977).  Findings of fact should include as many subsidiary facts as are necessary to disclose to the appellate court the basis upon which the judge reached the ultimate conclusions.  Woodrich Constr. Co. v. State of Minn., 177 N.W.2d 563 (Minn. 1970).

The threshold issue in this case was whether the employee sustained an injury arising out of and in the course of his employment.  In determining this issue, the compensation judge found the employee had no left shoulder injury or difficulty prior to November 19, 2011.  The judge found the employee injured his left shoulder on November 19, 2011, while moving a heavy safe at work, and aggravated his left shoulder the following day after sliding a heavy door at work.  Finally, the compensation judge concluded the surgery performed by Dr. Harms on March 13, 2012, was necessitated by the employee’s work injuries.  These findings disclose the basis for the judge’s decision and fully resolve the threshold causation issue.  The compensation judge’s factual findings are sufficiently detailed and specific to enable this court to perform a meaningful appellate review.

The compensation judge found the employee sustained a personal injury on November 19 and November 20, 2011.  In his memorandum, the compensation judge noted that there was “little evidence to contradict the occurrence of these incidents.”  The appellants contend that this statement by the compensation judge implicitly required the appellants to prove the non-occurrence of an incident and improperly shifted the employee’s burden of proof to the employer and insurer.  Accordingly, the appellants assert the compensation judge’s findings should be vacated.  We disagree.

The quoted sentence from the memorandum simply enumerates one of the bases for the judge’s causation decision.  The employee testified about two specific incidents at work that caused injury to his left shoulder.  In evaluating the credibility of this testimony, the compensation judge noted the absence of any testimony that the two incidents did not occur as the employee testified.  This observation did not shift the burden of proof.

The employer and insurer further contend the compensation judge’s decision is unsupported by substantial evidence.  They argue that the judge’s findings contain no discussion of any medical evidence and assert the only evidence relied upon by the judge was the employee’s testimony.  The appellants contend that, because their evidence was largely ignored, the compensation judge failed to weigh and evaluate all the evidence.  Accordingly, the appellants contend the judge’s findings are not supported by substantial evidence and should be reversed and remanded.  We do not agree.

The compensation judge made factual findings regarding the December 14, 2011, MRI scan, the employee’s work restrictions resulting from his personal injuries, the surgical report of Dr. Harms, and Dr. Wicklund’s independent medical evaluations.  The fact that a compensation judge does not specifically recite or refer to all of the medical evidence in the findings does not establish that the judge overlooked or failed to consider that evidence.  The compensation judge is not required to relate or discuss every piece of evidence received at the hearing.  See, e.g., Regan v. VOS Nat’l Housing, 61 W.C.D. 142 (W.C.C.A. 2000).  Given the record in this case and the compensation judge’s factual findings, we can only conclude the compensation judge did review and consider all of the medical evidence.

The appellants next assert that the opinions of Drs. Mullaney and Harms are insufficient to establish causation and fail to refute the opinions of Dr. Wicklund.  They argue the reports of Dr. Mullaney and Dr. Harms do not discuss how the injury occurred and provide no causation discussion or analysis.  Further, the appellants allege Dr. Harms’ report does not clearly opine the employee’s work injuries caused his pathology.  Accordingly, the appellants argue the opinions of Drs. Mullaney and Harms do not constitute substantial evidence upon which the compensation judge could have relied.

The competency of a witness to provide expert medical testimony depends upon the witness’s scientific knowledge and practical experience with the issue which is the subject of the offered testimony.  Reinhardt v. Colton, 337 N.W.2d 88, 93 (Minn. 1983).  In this case, both Dr. Mullaney and Dr. Harms obtained a history from the employee and performed a medical examination.  We have stated on many occasions that this level of knowledge about the subject matter affords adequate foundation for a doctor to render an expert medical opinion.  See Drews v. Kohl’s, 55 W.C.D. 33, 38-39 (W.C.C.A. 1996).  Further, an expert medical opinion does not lack foundation because the doctor fails to explain the mechanism of injury or the underlying reasons for the opinion.  Goss v. Ford Motor Co., 55 W.C.D. 316 (W.C.C.A. 1996).  Both Dr. Mullaney and Dr. Harms had adequate foundation for their opinions.

The employee testified that his job with the employer occasionally required heavy lifting which he was able to do without any left shoulder problems.  The employee also denied any left shoulder problems, treatment, or functional limitations prior to November 19, 2011.  The employee testified to the November 19 and 20, 2011, incidents at work which, he stated, resulted in severe left shoulder pain.  The next day, the employee saw Dr. Mullaney, gave a history of the two work incidents and complained of significant shoulder pain.  On examination, the doctor noted limited elevation and severely limited internal rotation of the left arm.  The doctor’s preliminary diagnosis was a rotator cuff or brachioradialis tear, and he referred the employee for an orthopedic consultation.  This evidence supports the compensation judge’s finding that the employee sustained personal injuries on November 19 and November 20, 2011.

The surgical report of Dr. Harms documented that the employee had significant shoulder damage including a labral tear and loose bodies in the subcoracoid recess.  Dr. Wicklund did not disagree with Dr. Harms’ surgical findings, but opined they pre-existed the November 19 and 20, 2011, incidents.  Dr. Mullaney and Dr. Harms opined the two work injuries were substantial contributing causes of the employee’s left shoulder condition.  These opinions provide substantial evidence supporting the compensation judge’s determination.

A personal injury may be established based upon the subjective complaints of the employee, coupled with the opinion of a medical expert that the employee’s disability arose out of and in the course of her employment.  Brown v. State, Dep’t of Transp., 56 W.C.D. 350 (W.C.C.A. 1997).  “If an opinion by a medical expert in a respected, recognized field of medicine is given with reasonable medical certainty, that opinion may, if the trier of fact chooses to rely on it, support a causal link between the worker’s disability and the job.”  Grunst v. Immanuel-St. Joseph Hosp., 424 N.W.2d 66, 67, 40 W.C.D. 1130, 1132 (Minn. 1988).  The employee’s testimony, coupled with the medical records and reports of Dr. Mullaney and Dr. Harms, provide substantial evidentiary support for the compensation judge’s decision, and that decision is affirmed.