The employee petitions to vacate an award on stipulation served and filed September 5, 1985, based upon a substantial change in his medical condition.  We deny the petition.

On October 22, 1966, Ronald L. Sherva, the employee, sustained a work-related injury to his left knee while working as a laborer for St. Regis Paper Co., which was insured for workers’ compensation liability by Travelers Insurance Co.  The employee underwent three surgeries on his left knee after the injury.  He was paid 61 weeks of temporary total disability benefits, 52 weeks of retraining benefits for retraining in computer repair, and 55 weeks of permanent partial disability benefits based on a 25% permanent partial disability rating of the left leg.  Travelers registered the employee’s injury with the second injury fund of the Special Compensation Fund, pursuant to Minn. Stat. § 176.131 (in effect at the time of injury, repealed 1992).

On July 3, 1972, the employee sustained a work-related injury to his right knee while working as a laborer for Wilson Sporting Goods Co., which was insured for workers’ compensation liability by Argonaut Insurance Co.  The employee underwent surgery on his right knee in 1972 and 1975.  Following his 1972 injury, the employee was paid 177 weeks of temporary total disability benefits, 55 weeks of permanent partial disability benefits for a 25% permanent partial disability rating of the right leg, and 104 weeks of retraining benefits while he attended dental technician training.  Argonaut was reimbursed for benefits paid through the second injury fund, subject to statutory deductibles.

After he completed his retraining in September 1975, the employee worked as a dental technician for Quadent Dental Lab in Wayzata, Minnesota, for two years, and then was transferred to Quadent’s lab located in Medford, Oregon.  As a dental technician, he made crowns, dentures, and other dental prosthetics.  Six months later Quadent went out of business.  The employee worked for Mountain View Dental Labs for one year, then opened his own dental lab where he was self-employed from 1978 until July 1984.  For his dental lab business, he retrieved impressions and other dental work orders from dentists, and performed laboratory work, which required standing, sitting, walking, and bending.

The employee continued to notice pain in both knees after he moved to Oregon, which precipitated his consultation with Dr. John Gilsdorf, an orthopedist in Medford, Oregon, in September 1977.  The employee reported aching in both knees aggravated by sustained walking and standing.  Dr. Gilsdorf noted post-traumatic degenerative changes which limited the employee to light and moderate ambulatory activities.  Dr. Gilsdorf indicated that the employee’s long term prognosis was gradual increased degenerative changes that could require further joint debridement, further chondroplasty patella, possible patellectomy, and possible knee replacements.

In February 1980, the employee underwent an arthroscopy-arthrotomy on the right knee, performed by Dr. Gilsdorf.  The employee remained off work following the surgery.  In April 1980, the employee underwent an arthroscopy with chondroplasty of the lateral femoral condyle of the left knee, also performed by Dr. Gilsdorf.  The surgeries were successful; by September 1980, the employee was experiencing a dull aching in his knees only after prolonged standing and he had returned to his regular work at his dental laboratory.  The employee treated with Dr. Gilsdorf until the doctor’s retirement in 1983; at that time the employee indicated that his knees hurt when he went hunting and walked on inclines.  The employee noted increased pain and swelling in both knees.  By July 1984, the employee had stopped operating his dental lab business because of his pain, difficulty bending his knees and difficulty driving.

In July 1984, the employee treated with Dr. Albert Winkler.  Dr. Winkler noted degenerative changes in both knees and concluded that the employee had become disabled on June 15, 1984.  Dr. Winkler gave a guarded prognosis due to the employee’s degenerative changes and commented that

In November 1984, the employee filed a claim petition against Argonaut and Travelers for temporary total disability benefits from and after July 15, 1984, which both insurers rejected.  The employee also filed a claim for Social Security disability benefits, which was accepted; according to his affidavit, the employee began receiving Social Security disability benefits in February 1985.  In June 1985, Dr. Winkler reiterated his opinion that the employee’s knee pain prevented him from returning to work as a dental technician, since he could not sit or stand for long periods of time.  He also advised that the employee eventually would be a candidate for total knee replacements but was too young at the time given the short life of knee replacements.

Due to Dr. Gilsdorf’s retirement, the employee began treating with Dr. Steven Chamberlain in December 1984, initially complaining of pain mostly in his left knee.  Dr. Chamberlain recommended surgery.  Also in December 1984, the employee saw Dr. Jerome Wiedel for a second opinion about his knee condition.  Dr. Wiedel diagnosed degenerative changes in both knees, recommended arthroscopic irrigation debridements for temporary relief, and suggested that the employee undergo therapy to promote muscle strengthening.  Dr. Wiedel opined that the employee could continue to work as a dental technician.

In January 1985, the employee underwent arthroscopic debridement and abrasion chondroplasty of the left knee, performed by Dr. Chamberlain.  The employee continued to have pain in his left knee after the surgery and also experienced pain in the right knee.  Dr. Chamberlain recommended surgery for the right knee, and in June 1985 the employee underwent an arthroscopy and resection of the plica on the right knee. Dr. Chamberlain predicted that the employee would ultimately need to undergo total knee replacements which he felt would reduce his knee pain and allow him to work as a dental technician.  The employee continued to see Dr. Chamberlain and was treated with steroid injections.

In July 1985, the employee was examined by Dr. Elmer Salovich at the request of Wilson Sporting Goods and Argonaut.  Dr. Salovich rated the employee as having 25% permanent partial disability of each leg and opined that the employee would be able to return to work as a dental technician with some restrictions and the use of a cane.

In August 1985, the parties reached a full, final, and complete settlement of the employee’s claims in exchange for $33,544.50, which, according to the stipulation for settlement, represented 165 weeks of temporary total disability benefits at the supplementary benefit rate, plus payment of $6,490 in additional permanent partial disability benefits.  The parties agreed that the employee had exhausted his rights to rehabilitation benefits for the 1966 and 1972 work injuries, and that St. Regis Paper and Travelers could be dismissed from the action.  An award on stipulation was served and filed on September 5, 1985.

The employee continued to treat with Dr. Chamberlain after the award on stipulation.  In January 1987, Dr. Chamberlain performed a debridement of the medial lateral femoral condyles of the employee’s left knee.  In August 1987, Dr. Chamberlain performed bilateral arthroscopies of the employee’s knees.  The employee was able to walk with use of a crutch or a cane.  Dr. Chamberlain performed further bilateral debridements in May 1991, December 1992, and May 1996, right knee debridements in December 1994 and March 2000, and left knee debridements in March 1994 and April 1998.  The employee was also treated with steroid injections and Synvisc injections over the years.  In 2002, Dr. Chamberlain opined that the employee was capable of performing sedentary work, and that his only treatment option was bilateral total knee replacements, after which he could perform sedentary or light-duty work.

In January 2004, the employee was evaluated by Dr. Glen O’Sullivan.  Dr. O’Sullivan opined that the employee should proceed with the total knee replacements and that he was unable to work because of the combined effects of his back, knee and hip pain.  In March 2004, a colleague of Dr. Chamberlain, Dr. Yaser Metwally, took over the employee’s treatment from Dr. Chamberlain.  He noted that the employee had severe degenerative arthritis in both knees and recommended bilateral total knee arthroplasty.  A right total knee arthroplasty was performed on June 22, 2004.  The employee underwent physical therapy but still had limited range of motion.  The employee’s symptoms of pain and swelling of the right knee persisted, and, in October 2004, Dr. Metwally assigned the employee restrictions of no lifting over 25 pounds, occasional bending, climbing, standing, walking, or driving, and to avoid twisting, squatting, or kneeling.  Dr. Metwally treated the left knee with injections and recommended a left total knee arthroplasty.  That procedure was postponed, however, when the employee was involved in a motor vehicle accident in February 2007.  According to Dr. Metwally’s report of August 8, 2005, he diagnosed extensive degenerative arthritis of both knees, with a very limited range of motion.  In his opinion, the employee’s progressive worsening of his condition had affected both of his knees and his ambulation ability, which in turn affected his hips and lumbar spine.

Dr. Ruth Logenwart, who had treated the employee for upper body conditions, examined the employee in May 2006 and opined that the employee was disabled from any gainful employment, noting that the employee had to lie down more than 15 times a day due to his inability to sit or stand.

In his affidavit, the employee stated that he is reluctant to undergo a left total knee replacement at this time, given the lack of success with his right knee arthroplasty and in view of the severe degeneration of his left knee which he understands makes it unlikely that the procedure will improve the functioning of his left knee.  He continues to note severe pain and swelling in both knees, uses OxyContin and methadone for his pain, and uses a cane while walking because of the weakness, pain and instability in his knees.  The employee believes that he is unable to perform any type of gainful employment as a result of his bilateral knee condition.

This court’s authority over petitions to vacate is governed by Minn. Stat. § 176.461 and 176.521, subd. 3.  An employee must demonstrate good cause for the court to exercise this authority.  Stewart v. Rahr Malting Co., 435 N.W.2d 538, 539, 41 W.C.D. 648, 649 (Minn. 1989).  For awards issued prior to July 1, 1992, such as in this case, "good cause" is limited to: 1)  a mistake of fact; 2)  newly discovered evidence; 3)  fraud; or 4)  a substantial change in medical condition since the time of the award.  Franke v. Fabcon, Inc., 509 N.W.2d 373, 49 W.C.D. 520 (Minn. 1993); Krebsbach v. Lake Lillian Coop. Creamery Ass'n, 350 N.W.2d 349, 353, 36 W.C.D. 796, 801 (Minn. 1984).  For petitions to vacate an award on stipulation entered into before July 1, 1992, it is not required to show that the substantial change in condition was clearly not anticipated.  The burden of proving “good cause” rests with the party petitioning to vacate an award.  Mehta v. Meldisco, slip op. (W.C.C.A. Oct. 26, 1995).

The employee argues that there has been a substantial change in his medical condition.  In determining whether a substantial change in medical condition has occurred, this court may examine such factors as a change in diagnosis, a change in the employee’s ability to work, additional permanent partial disability, the necessity of more costly and extensive medical care/nursing services than initially anticipated, the causal relationship between the injury covered by the settlement and the current worsened condition, and the contemplation of the parties at the time of the settlement.  Fodness v. Standard Café, 41 W.C.D. 1051, 1060-61 (W.C.C.A. 1989).

The parties agree that the employee’s work injuries remain substantial contributing factors to the employee’s current condition.  The employee, however, argues that his diagnosis has changed because his arthritis condition has degenerated to the level of end stage arthritis.  In this case, the doctors’ opinions at the time of the settlement clearly indicated that the employee’s condition would continue to worsen, and it has done so. Although the employee’s condition has degenerated since the award on stipulation, his underlying diagnosis remains the same.

As to additional factors addressed by Fodness, the employee is not claiming additional permanent partial disability.  While the employee has undergone extensive medical treatment, under the terms of the stipulation for settlement the employee’s claims for medical expenses were left open, with compensable medical expenses payable by Wilson Sporting Goods and Argonaut.

The employee’s main argument is that there has been a change in his ability to work, another factor articulated in Fodness.  At the time of the settlement, the employee claimed that he had been temporarily totally disabled from all gainful employment since June 15, 1984, and that he was a candidate for bilateral total knee replacements and had sustained at least 50% permanent partial disability of both legs.  At the time of the settlement, St. Regis Paper and Travelers argued that their responsibility for any additional payment was discharged because second injury coverage existed.  Wilson Sporting Goods, Argonaut and the Special Compensation Fund argued that the employee’s disability was not related to his 1972 work injury, but instead was due to work-related aggravations sustained in various employments since 1977.  They also contended that the employee was “able to perform light and sedentary work activities in spite of his bilateral knee injuries” and therefore could perform numerous jobs, including his employment as a dental technician.

The employee acknowledges that he had indicated in the stipulation that he was unable to work as a dental technician because of his recent operations.  He argues, however, that at the time of the settlement, he believed he would be able to return to work once he recovered from those surgeries, and also that he would undergo total knee replacements in the future which would allow him to work.  The employee notes that doctors who examined him at the time of the settlement, Dr. Chamberlain, Dr. Wiedel, and Dr. Salovich, indicated that he was capable of working as a dental technician and that total knee replacements would allow him to work as a dental technician in the future.  Dr. Chamberlain had predicted that the employee would undergo total knee replacements which, he opined, would reduce his knee pain and allow him to work as a dental technician.  Dr. Wiedel had diagnosed degenerative changes in both knees, recommended arthroscopic debridements for temporary relief, and opined that the employee could work as a dental technician.  Dr. Salovich had opined that the employee would be able to return to work as a dental technician with some restrictions.

The employee’s physicians recommended that he wait to undergo the total knee replacements because of his relatively young age and the short life of artificial knee joints.  The employee argues that his knee condition degenerated so quickly that by the time he was a candidate for the knee replacement surgery, the outcome was not as positive as was earlier predicted.  In June 2004, the employee underwent a right total knee replacement, which did not improve his knee function or his ability to work.  At the time his petition to vacate was filed, the employee had not yet undergone a left total knee replacement, although he anticipated that he would do so in the future.

"[T]he basic concern in determining whether sufficient cause exists to set aside an award is to assure a compensation proportionate to the degree and duration of the disability."  Krebsbach v. Lake Lillian Coop. Creamery Ass'n, 350 N.W.2d 349, 353-54, 36 W.C.D. 796, 801 (Minn. 1984).  When evaluating a petition to vacate, this court compares the employee’s condition at the time of the settlement award to his condition at the time of the filing of the petition.  See Virnig v. Carley Foundry, Inc., slip op. (W.C.C.A. Nov. 14, 2000) (citing Clonkey v. Clusiau Sales and Rental, slip op. (W.C.C.A. Dec. 9, 1991)).  The employee was not able to work at the time of the settlement after discontinuing his dental lab business in mid-1984.  At the time of the award, he was receiving Social Security disability benefits, and has not worked since the time of the award.  The employee has not shown a change in his ability to work.

At the time of the settlement, the employee was totally disabled and his doctors anticipated the need for bilateral knee replacements.  He was collecting Social Security disability benefits.  The parties anticipated the need for significant ongoing medical treatment, which continues to be paid for under the terms of the settlement.  The employee remains totally disabled at the present time and continues to receive Social Security disability benefits.  Under the circumstances presented and considering the availability of medical coverage under the stipulation, we conclude that the employee has not established that he has experienced a substantial change in medical condition since the time of the award on stipulation that is sufficient to vacate the award on stipulation.  We therefore deny the petition.