Dayton Hudson appeals from the compensation judge’s determination that the employee’s June 28, 1996, work injury is a substantial contributing factor in her present disability and from the compensation judge’s award of contribution to be made by Dayton Hudson to Target Corporation.  We affirm.

Janet Beise began working for Dayton Hudson at the Brookdale mall in 1984.  She worked in a food court and prepared and served items such as hot dogs and frozen yogurt.  Ms. Beise described the job as physical, requiring prolonged standing as well as lifting and carrying boxes of product which could weigh up to fifty pounds.  She had no back problems when she began this job and was able to handle the physical aspects of her duties with no difficulty.

Ms. Beise first sought medical care for her low back on February 20, 1987, when she went to urgent care at Park Nicollet Medical Center.  The history she provided there was of low back discomfort after lifting some heavy objects at work.  She was diagnosed as having a low back sprain advised to use heat and an anti-inflammatory medication such as Advil.  She was taken off work for two days and was then placed on light-duty work for ten days.  Ms. Beise did not recall this incident and she did not treat for her low back again until April 1988.

At that time, Ms. Beise returned to urgent care at Park Nicollet with symptoms of low back pain and radiation of pain into her right buttock.  The diagnosis remained low back strain and Ms. Beise was given Motrin and activity restrictions for a short time.  Ms. Beise treated a few more times for her low back pain before her injury in June 1996.  In July 1988, she was diagnosed with low back pain with sciatica, given Motrin, and referred to physical therapy for three treatments.  In January 1989, she was at urgent care for low back and right thigh pain.  Ms. Beise was provided with two physical therapy visits at that time.  In July 1989, Ms. Beise saw a doctor for a scheduled physical and mentioned that Ashe occasionally gets a right low back ache going down her leg.  No mention was made of low back problems at her physical in December 1990.

At a clinic visit in August 1991, Ms. Beise related that she had stepped wrong going down stairs at home and had low back pain.  She was told to use ice alternating with heat and was given anti-inflammatory medication and pain relievers.  There was no return visit for this incident.  At a routine physical exam in March 1992, she mentioned that she Aperiodically will get some right buttock pain that goes down her leg, especially if she has been standing for a long period of time.  In x-rays taken in March 1992, mild degenerative changes are noted at L2-3 and L3-4 with some hypertrophic spurring and slight narrowing of the joint spaces.

In May 1993, Ms. Beise saw her physician at Park Nicollet and reported right buttock pain, aches down her leg, ankle hurts.  She attributed her symptoms to the standing associated with her job.  Her doctor provided Naprosyn and advised icing and physical therapy.  Ms. Beise had two physical therapy treatments.  Her next visit for low back pain was almost a year later when she saw her general practice doctor in April 1994.  Ms. Beise was prescribed Naprosyn, Flexerol, icing, and was advised to increase bed rest for the next three days.  She was given lifting restrictions at work for one week.  Dayton Hudson admitted a work injury to the low back as of April 22, 1994, as the result of continued lifting.  On return on June 9, her doctor noted the back strain had resolved.

At the hearing, Ms. Beise generally had no recollection of these incidents or of medical visits for her low back.  She continued to perform her regular duties at Dayton’s and at some point transferred to Dayton’s in the Ridgedale mall.  She then became a supervisor and supervised employees in the food court and also continued to perform duties which included lifting and moving boxes of product.

On June 28, 1996, Ms. Beise was lifting a case of frozen yogurt weighing about fifty pounds.  As she turned, she experienced what she described as extreme pain in her low back.  She sought medical care at Park Nicollet on July 9 and reported constant pain going down her right posterior thigh into her calf as well as numbness and tingling in her foot.  Ms. Beise was given medication and was told to return if her symptoms did not resolve.  Ms. Beise was also taken off work and remained off work for more than ten weeks.  Dayton Hudson accepted liability and paid workers’ compensation benefits.

When she returned to Park Nicollet on July 16, she reported constant pain which prevented her from working and from sleeping more than two or three hours at a time.  She had burning, tingling, and numbness in her thigh and lower leg which went into her foot.  The diagnosis on that date was lumbar radiculopathy.  A CT scan done on July 23, 1996, was read as showing a bulging disk at the L4-5 level, with diffuse mild bilateral foraminal stenosis, worse on the right.

Lumbar myelography done on August 1, 1996, showed small herniations of the L4-5 and L3-4 disks and a central bulging disk at the L5-S1 level.  She was seen for neurological consultation by Dr. Edward Hames, who felt surgery was not an option at that time.  Ms. Beise was referred to a neurologist, Dr. Daniel Freking.  He ordered a lumbar MRI which showed a diffuse mild-to-moderate annular disk bulge at L1-2, L4-5 and L5-S1.  There are no direct signs of impingement upon the right L5 nerve root.

When Ms. Beise was examined by Dr. Freking on September 17, 1996, she reported right leg pain, numbness and weakness.  Ms. Beise reported her previous low back problems to Dr. Freking, but told him that her present condition is definitely a new problem with more significant leg symptoms.  Dr. Freking recommended an EMG which was done on October 8, 1996.  Dr. Freking read the EMG as right peroneal neuropathy.  No clear evidence of radicular findings.

When Ms. Beise completed the work-hardening program and returned to Dr. Freking, she reported some improvement in strength and activity tolerance.  Pain intensity was about the same.  She still had weakness and tingling in her right leg, and her pain was aggravated by activity.  Dr. Freking’s impression on November 12, 1996, was “chronic low back pain with right buttock and right leg pain, L4-5 bulged disk, with right L5 radiculopathy.”  Dr. Freking made no further treatment recommendation other than a home exercise program.

Ms. Beise returned to work at Dayton Hudson on a part-time basis with work restrictions.  Her initial job was a desk job in which she used a telephone to locate merchandise.  In January 1997, she began treating with the Physical Medicine Department at Park Nicollet.  Her treatment continued to be the home exercise program and the use of Naprosyn and pain relievers.  It was noted in April 1997 that when she tried to increase her daily hours from six to seven that she had more symptoms and was not able to engage in other activities at home.

Dr. Daniel Kurtti, physical medicine specialist at Park Nicollet, saw Ms. Beise on October 15, 1997.  He assessed chronic low back pain with right leg pain, right L5 radiculopathy, L4-5 disk bulge and mild neural foramen narrowing and facet joint arthropathy.  He found her to be at MMI, rated her as having 12% permanent partial disability under Minn. R. 5223.0390, subp. 4.D., and continued the work restrictions set after her work-hardening program.  Dayton Hudson paid the permanent partial disability rated by Dr. Kurtti.

Ms. Beise testified that her back never returned to the condition it had been in before her 1996 work injury.  Ms. Beise returned to Park Nicollet for her low back occasionally between 1998 and August 2000, but no additional treatment options were provided to her.

In May 1998, Ms. Beise was seen by Dr. Robert Hartmann for an independent medical evaluation on behalf of Dayton Hudson.  His opinion was that the 1996 work injury was a temporary aggravation of a preexisting condition and that the aggravation had resolved with no permanent partial disability or restrictions related to the work injury.

At some point, Ms. Beise’s job of locating merchandise was moved to the area of the store where the bridal registry was located.  Over time, she ended up taking on duties of that department and was once again on her feet on the sales floor for a significant part of the day.  She testified at the hearing that the work duties aggravated her low back.

Ms. Beise left Dayton Hudson in July 2000 to go to work for Target because of her low back pain.  Her new job at Target involved sitting at a desk and handling customer calls.  On August 24, 2000, Ms. Beise tripped over her purse while leaving her desk and injured her low back further.  She described the pain as being in the same area where she had been experiencing her low back pain, but also described the pain as more intense.

Ms. Beise’s initial medical treatment after the 2000 injury consisted of further conservative care, including physical therapy.  In October, she had an MRI which was read as being very similar to the MRI done in 1996, after the 1996 work injury.  Ms. Beise was referred to a neurosurgeon, Dr. Mark Larkins, in February 2001.  Dr. Larkins recommended surgery and on May 23, 2001, performed a L4-5, L5-S1 laminectomy, microscopic discection, right L5 foraminotomy, repair of dural rent.  Ms. Beise developed an infection at the surgical site which required additional surgery in July 2001.  A third surgery was performed in December 2003.  Ms. Beise’s low back has never returned to the condition it was in before August 2000.  Ms. Beise has not returned to work and has not been released to return to work by her treating doctors.

Target, the 2000 employer, initiated payment of wage loss benefits after the 2000 injury and has paid medical expenses related to Ms. Beise’s treatment.  In March 2007, Target filed a petition for contribution against Dayton Hudson.  The petition was heard by Compensation Judge Gary Hall on May 20, 2008.  At the hearing, the parties stipulated that the payments made by Target, including the payments for medical treatment, were reasonable and necessary.

Target presented the deposition testimony of Dr. Paul Cederberg at the hearing.  Dr.Cederberg’s initial evaluation of Ms. Beise was on May 11, 2001, and there were further examinations in October 2003 and July 2006.  Dr. Cederberg concluded that Ms. Beise sustained a permanent aggravation of a preexisting condition on June 28, 1996.  In support of his conclusion, Dr. Cederberg referred to the medical records which did not diagnose radiculopathy until after the 1996 injury.  He also cited to the history provided by Ms. Beise that her back condition never returned to its pre-1996 condition.  Dr. Cederberg was also of the opinion that there had been a permanent injury on August 24, 2000, and he apportioned responsibility for Ms. Beise’s disability and medical care after that date.  According to Dr. Cederberg, each injury was responsible for 50% of Ms. Beise’s condition.

Dayton Hudson introduced the deposition testimony of Dr. Mark Friedland, who examined the employee on September 17, 2007.  Dr. Friedland stated that the 1996 work injury was a temporary aggravation of a preexisting condition and that the 2000 injury was 100% responsible for Ms. Beise’s condition after that date.  Dr. Friedland supported his opinion with the 1996 EMG which had been read as showing a peroneal neuropathy with no evidence of radiculopathy.  According to Dr. Friedland, this was evidence that Ms. Beise did not develop a radiculopathy after her 1996 injury and that her condition before and after 1996 was essentially the same.

In his findings and order of July 7, 2008, the compensation judge adopted the opinions of Dr. Cederberg and apportioned liability for Ms. Beise’s disability and medical treatment in accordance with those opinions.  Dayton Hudson appeals.

Dayton Hudson argues on appeal that the compensation judge’s findings are not supported by substantial evidence in the record.  Dayton Hudson contends that the only reasonable interpretation of the medical evidence demonstrates that the 1996 injury was nothing more than a flare up of a preexisting condition.  We disagree.

Ms. Beise did not dispute that she had low back problems before her 1996 work injury.  The medical records, however, show a total of seven doctor appointments for back pain over a period of nine years before the 1996 injury.  Further, Ms. Beise was able to continue working at Dayton Hudson at a job which required significant prolonged standing as well as lifting of weights up to fifty pounds.  At the time of her 1996 work injury, Ms. Beise had no work restrictions for her low back.

The compensation judge found Ms. Beise to be a credible witness and she testified specifically that after the 1996 work injury her back never returned to the condition that it had been in before the work injury.  Her testimony was supported by her work history.  She was never able to return to her pre-injury duties and worked thereafter with restrictions until her injury in August 2000.  Further, in contrast to the records before June 1996, the medical records after the 1996 injury show consistent symptoms of constant pain, numbness and leg weakness.

The compensation judge’s decision is also supported by the opinion of Dr. Cederberg, who concluded that the 1996 work injury was a permanent aggravation of Ms. Beise’s previous condition and also concluded that the 1996 work injury was a substantial contributing factor in Ms. Beise’s ongoing condition.  Dr. Cederberg based his conclusion in part on the history provided by Ms. Beise, but also on the testing after June 1996 which showed a positive straight leg raising test on the right which Dr. Cederberg testified was evidence of L5 radiculopathy.  He also referred specifically to the records of Ms. Beise’s treating physicians, Dr. Kurtti and Dr. Larkins.

Dr. Cederberg having evaluated Ms. Beise on three occasions and having reviewed her medical records, had adequate foundation for his opinion.  While Dayton Hudson argues on appeal, as it did at the hearing, that the compensation judge should have adopted the opinion of Dr. Friedland, it is the role of the compensation judge to choose between competing medical opinions.  Lowell v. Lee Stamping, 63 W.C.D. 304 (W.C.C.A. 2003); Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  This court will generally affirm a compensation judge’s determination which is based on choice of medical opinion as long as the medical opinion relied upon has adequate foundation.

The compensation judge here opted to follow the opinion of Dr. Cederberg, in substantial part, because that opinion was most consistent with the testimony and medical records of Ms. Beise.  Equitable apportionment is a fact issue for the compensation judge.  Evans v. Asphault Driveway, slip op. (W.C.C.A. Oct. 7, 2003); Ringena v. Ramsey Action Programs, 40 W.C.D 880 (W.C.C.A. 1987).  Substantial evidence supports the decision of the compensation judge in this matter and the decision is affirmed.