The employee appeals the compensation judge’s finding that the employee’s 2005 work injury was not a substantial contributing factor in the employee’s wage loss from and after August 13, 2007.

Thomas A. Johnson, the employee, worked as a route delivery driver for AmeriPride Services, the employer, for over 26 years between February 1979 and September 2005.  As a customer service representative, he drove a truck or van picking up and delivering linens, rugs and clothing from various clients.  According to the employee, he worked an average of 42 to 46 hours per week, working 4 days per week.  The employee estimated that on each day, he drove approximately 2 hours, made 16 - 24 stops and at each stop worked between 15 minutes and up to 1-2 hours.  He delivered garments on hangers, rugs, bundles of towels, and soap products, and also picked up soiled linen from clients in garment bags or wheeled baskets.  In addition, he updated his account information, and occasionally performed collection work and customer surveys.

On September 11, 2005, the employee hurt his right elbow at home and was unable to work.  The elbow symptoms resolved, but the employee was diagnosed with carpal tunnel syndrome in his right arm by Dr. Mark Holm.  On January 27, 2006, the employee underwent carpal tunnel release surgery performed by Dr. Holm.  The employee was released to work without restrictions as of May 6, 2006.  The employee filed a claim petition on May 31, 2006, which was amended on May 2, 2007, for wage loss benefits and medical expenses related to carpal tunnel syndrome and ulnar nerve problems in his right arm.  A hearing was held on August 10, 2007.

In a November 7, 2007, Findings and Order, Compensation Judge James Cannon determined that the employee had sustained a Gillette^[2] injury in the nature of right carpal tunnel syndrome as of September 15, 2005, and awarded temporary total disability benefits from the date of his carpal tunnel surgery on January 27, 2006, until May 1, 2006, the date on which the employee was released to full-duty work.  The compensation judge also awarded medical expenses related to treatment for carpal tunnel syndrome incurred during that same time period.  The compensation judge denied the employee’s claim that he had also sustained a right ulnar nerve injury culminating on September 15, 2005, and denied the employee’s claim for temporary total disability benefits between his injury date and his carpal tunnel surgery on January 27, 2006.  The compensation judge determined that the employee had not been temporarily totally disabled from employment during that period of time as a result of his work-related carpal tunnel syndrome, because the work restrictions placed on him during this period were related to his right elbow and not to his carpal tunnel syndrome.  The judge also denied the employee’s claims for benefits and payment of medical expenses after May 1, 2006, on the basis that any disability and need for medical treatment after that date was not related to his work injury.  The employee appealed from the denial of his claims related to his ulnar nerve condition.  This court affirmed the compensation judge’s decision.  Johnson v. Ameripride Services Inc., No. WC07-279 (W.C.C.A. Oct. 6, 2008).

As of June 18, 2007, the employee has been working full time with Auto Uplink, a position he obtained with assistance from his QRC.  Auto Uplink is an internet advertising agency for used cars.  At first, the employee would document used vehicles at car dealerships and print window stickers for the cars.  Later, the employee was transferred to a different position with this employer where he would inspect, document, and photograph the used vehicles.  There is no heavy lifting in this position and the employee testified that the position is within his restrictions.  The employee earns $16.00 per hour and has an ongoing wage loss.  He stopped his job search after starting work with this employer and the QRC closed vocational rehabilitation services.

In November 2007, the employee returned to Dr. Holm for a recheck, reporting that his right hand was tingly and numb.  Dr. Holm recommended nerve conduction studies on the employee’s right median and ulnar nerves, which indicated abnormal findings for the employee’s right ulnar nerve.  Dr. Holm recommended ulnar nerve transposition surgery at the right elbow and an ulnar tunnel release at the right hand.  The employee treated with Dr. Holm again on October 6, 2008, reporting right elbow symptoms and right shoulder pain, which he did not claim to be work related.  Dr. Holm diagnosed chronic ulnar neuritis, right shoulder pain secondary to impingement syndrome, and right shoulder AC joint arthritis.  Recommended treatment included subacromial decompression for the right shoulder, ulnar nerve transposition or decompression for the elbow, and ulnar tunnel release at the right wrist.

On April 20, 2009, the employee filed a claim petition for temporary partial disability benefits from and after August 13, 2007, which was three days after the previous hearing.  The employer and insurer objected, claiming that any alleged disability was not related to the employee’s September 15, 2005, work-related injury.  On July 20, 2009, the employee was examined by Dr. Call at the employer and insurer’s request.  Dr. Call opined that the employee did not have symptoms or findings consistent with right carpal tunnel syndrome and he did not recommend any work restrictions related to carpal tunnel syndrome.  He stated that the employee did not have recurrent carpal tunnel syndrome and that the employee’s previous carpal tunnel syndrome was not a substantial contributing factor in the employee’s symptoms or work restrictions.  He reiterated his opinions after reviewing additional records in a July 12, 2010, report.

In February 2009, Dr. Holm gave the employee restrictions of avoiding vibrating tools and lifting with the right hand of more than 10 pounds frequently, 20 pounds occasionally, and 30 pounds rarely.  On December 7, 2009, the employee reported increasing right hand symptoms.  Dr. Holm noted negative Tinel’s sign and recommended NeuroMetrix nerve conduction testing.  That testing was performed on December 15, 2009, and interpreted as normal.  Dr. Holm recommended restrictions at that time of no repetitive gripping, grasping, or vibrating with the right hand, and maximum lifting of 20 pounds with both hands.  On July 13, 2010, the employee reported weakness and frequent tingling and numbness in his right hand to Dr. Holm, who noted weakly positive Tinel’s sign and positive NueroMetrix testing on that date for carpal tunnel syndrome on the right hand.  Dr.  Holm and the employee discussed possible carpal tunnel release surgery.  The employee was able to continue working for Auto Uplink through the date of the hearing.

A hearing was held on July 30, 2010.  The compensation judge found that the employee’s September 15, 2005, carpal tunnel injury is not a substantial contributing factor in the employee’s wage loss from and after August 13, 2007.  The employee appeals.

An employee is entitled to temporary partial disability benefits “while the employee is employed, earning less than the employee’s weekly wage at the time of the injury, and the reduced wage the employee is able to earn in the employee’s partially disabled condition is due to the injury.”  Minn. Stat. § 176.101, subd. 2(b).  In order to demonstrate entitlement to temporary partial disability, an employee must demonstrate a work-related physical disability and an actual loss of earning capacity that is causally related to the disability.  Krotzer v. Browning-Ferris, 459 N.W.2d 509, 43 W.C.D. 254 (Minn. 1990).  The employee has the burden of proving that the wage loss was causally related to the work injury.  Borchert v. American Spirits Graphics, 582 N.W.2d 214, 215, 58 W.C.D. 316, 318 (Minn. 1998).

The compensation judge found that the employee’s September 15, 2005, carpal tunnel injury is not a substantial contributing factor in the employee’s wage loss from and after August 13, 2007, since the employee did not have work restrictions related to his injury.  An employee who has no residual disability related to the work injury is not entitled to continuing compensation.  Kautz v. Setterlin Co., 410 N.W.2d 843, 40 W.C.D. 206 (Minn. 1987).  Central to the definition of disability is a requirement that the employee must have restrictions from his or her work injury which interferes with a return to employment.  The issue of whether the employee has any residual disability and is able to return to work without restrictions related to the work injury is a question of fact for the compensation judge to determine.  Hoy v. Employment Plus, slip op. (W.C.C.A. Sept. 3, 2003).

The compensation judge noted in his memorandum that the employee’s work-related carpal tunnel syndrome was previously found to not be a substantial contributing factor of the employee’s temporary total disability from May 2, 2006, through August 10, 2007.  This finding was not appealed.  He also noted that even though the employee’s right hand complaints had increased, there had been no objective change in his underlying medical condition, relying on Dr. Call’s opinion.  Dr. Call opined that the employee did not have symptoms or findings consistent with right carpal tunnel syndrome and did not have work restrictions related to carpal tunnel syndrome.  He stated that the employee did not have recurrent carpal tunnel syndrome and that the employee’s previous carpal tunnel syndrome is not a substantial contributing factor in the employee’s symptoms or work restrictions, and reiterated his opinions after reviewing additional records in a July 12, 2010, report.

The employee argues that Dr. Call’s opinion lacks foundation since Dr. Holm’s July 13, 2010, chart note, stating that the employee had positive Tinel’s sign and positive NueroMetrix testing on that date for carpal tunnel syndrome on the right hand, was not made available to Dr. Call before the July 30, 2010, hearing.

Dr. Call’s last report, after additional medical review, was dated July 12, 2010.  Dr. Call obtained a history from the employee, reviewed the employee’s medical records and examined the employee.  As a general rule, this level of knowledge establishes a doctor’s competence to render an expert opinion.  See Grunst v. Immanuel-St. Joseph Hosp., 424 N.W.2d 66, 40 W.C.D. 1130 (Minn. 1988).  The fact that Dr. Call was not aware of Dr. Holm’s July 13, 2010, chart note goes to the weight afforded the medical opinion by the compensation judge, not its foundation.  The dates of Dr. Call’s last report and Dr. Holm’s chart note were clearly noted by the compensation judge in his Findings and Order.  The employee’s claim for temporary partial disability benefits was for a period of time beginning August 13, 2007.  The compensation judge could reasonably conclude that Dr. Call’s opinion that the employee’s September 2005 work injury was not a substantial contributing cause in the employee’s current condition would not change based on this additional symptom in July 2010.

A compensation judge’s decision whether or not to rely on a given medical opinion that is being considered in evidence is a matter of credibility, and a judge’s decision not to credit and rely on an opinion is the judge’s prerogative.  Nord v. City of Cook, 360 N.W.2d 337, 342-43, 37 W.C.D. 364, 372-73 (Minn. 1985).

It is the function of this court to review the record to determine whether substantial evidence exists to support the findings of the compensation judge, not to determine whether substantial evidence supports a contrary conclusion.  Concluding that the compensation judge’s decision in this case was not unreasonable and is adequately supported by the evidence, we affirm.  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).