OPINION
The Workers’ Compensation Court of Appeals denied a petition to vacate an award on settlement agreement. We reverse and remand.
After conservative measures failed to alleviate Monson’s low back symptoms, on November 21, 1994, Monson underwent anterior lumbar interbody fusion surgery with BAX cages at the L4-5 and L5-S1. That surgery failed and on June 19, 1995, Monson underwent facet fusion and augmentation surgery. His surgeon, Dr. John Dowdle, said “[t]he 5-1 level was fused solid and there was minimal or no motion that took place at the 4-5 level. There was a mild amount of motion with distraction.”
Following the second surgery, when X-rays indicated “healing fusion at the 4-5 level,” Dr. Dowdle released Mon-son to work with restrictions. Through rehabilitation efforts, on January 2, 1996, Monson started working for Kline Auto World (Kline) as an auto service writer. 1 When Monson’s low back symptoms persisted, Dr. Dowdle ordered an MRI, the results of which were read as indicating that the “implants [were] in good position[;]” that there was “bridging bone an-teriorly[;]” and “good bridging bone across the facet joint also.” Monson was also refеrred to neurologist Dr. Thomas McPartlin who ordered an EMG, the re-suits of which indicated “denervation of paraspinal muscles from the previous surgery” in 1994 but “no evidence of a radicu-lopathy.”
Monson’s back-related symptoms persisted. Dr. Dowdle restricted Monson from working and started him on a regular walking program. When additional diagnostic studies indicated “no substantial significant nerve root compression,” Dr. Dowdle referred Monson to the Pain Management Program at United Hospital. Monson participated in United’s Pain Management Program, under the direction of Dr. Todd Hess, from July 8, 1996 through August 9, 1996. At the end of the program, Dr. Hess noted that Monson described improvement in his outlook but continued to suffer fairly significаnt and limiting pain. Dr. Hess recommended continued psychotherapy and acupressure.
In a follow-up exam with Dr. Hess on January 2, 1997, Monson said that he was not improving; and on February 12, 1997, Monson told Dr. Hess that there had been “no improvement whatsoever” and that there was “absolutely no way” he could return to work. They discussed work-related and pain-related issues at length. Dr. Hess, believing that a return to work would be in Monson’s best interest, asked Monson to reassess his “adamancy” about his total disability; and on March 14, 1997, the doctor released Monson to return to work with restrictions. The doctor also recommended continued counseling and pool therapy.
On November 30, 1998, Monson’s vocational consultant (VC) reported that he had contacted Monson to review his medical status and return-to-work situation. Monson told the VC that he had experienced an increase in low back and leg symptoms but was unsure why that had happened. Monson and his VC also discussed transferring Monson’s pain management care from Dr. Hess to Monson’s family physician so as to alleviate the necessity for Monson to miss work to meet with Dr. Hess.
In December 1998, Monson and Mitsubishi/Western National negotiated a settlement for $112,500. The agreement also provided that $13,000 in attorney fees, previously withheld from past benefits paid, would be released to Monson’s attorney. The settlement agreement recited that Monson claimed he was entitled to ongoing temporary partial disability benefits as well as permanent partial disability bеnefits at the economic recovery compensation rate (less impairment compensation already paid) and retraining benefits; 2 that White Bear Mitsubishi/Western National claimed that Monson was not entitled to retraining and that permanent partial disability benefits had been fully paid at the impairment compensation rate; аnd that in compromise of the disputed claims, with the exception of future medical bills, Mon-son accepted the lump sum payment as a “full, final and complete settlement” of all claims arising out of the injury of March 28, 1991. White Bear Mitsubishi/Western National reserved all defenses arising out of future workers’ compensation claims of Monson. The settlement agreement was approved and an award issued on December 14,1998.
On September 30, 1999, Monson underwent surgery for cage removal, repair of pseudoarthrosis and posterior stabilization with screw/rod regrafting and decompression. On October 4, 2000, Dr. Perra noted that while Monson had improved somewhat, he continued to have severe pain. The doctor concluded that Monson had reached a “plateau” and was “likely completely disabled based on his degree of chronic pain and the medications necessary for this.” About a week later, Dr. Hess also concluded that Monson was permanently totally disabled: “It just does not at this point appear that the patient is employable.”
In a narrative report dated November 14, 2000, Dr. Perra stаted his opinion that based on the June 16, 1999 examination and subsequent surgery, Monson’s fusion at L5-S1 never solidly healed; The doctor said that the cages were loose at the time of the surgery in 1999 and that they had clear lucency around them. It was his opinion that this was characteristic of an area that had never been healed and not of an аrea that had healed and then become loosened. Dr. Perra was not aware of any information suggesting that this was known to Monson’s previously treating physicians.
On January 21, 2001, Monson was awarded social security disability benefits, retroactive to February 2,1999.
In July 2002, Monson filed a petition to vacate the 1998 award on grounds of substantial change in condition, mistake and newly discovered evidence, appending his medical records, including the reports from Dr. Perra, and the settlement agreement. The Workers’ Compensation Court of Appeals (‘WCCA”) denied the petition. Although the WCCA noted this was a “close case,” it concluded that Monson had not proven an unanticipated increase in disability, that any mistake was not material and that evidence not in existence at the time of settlement was not newly discovered evidence for purposes of vacating the award. Monson sought review by cer-tiorari. Minn.Stat. § 176.471 (2002).
I.
At the outset, it is worth bearing in mind that a workers’ compensation claim is not a private personal injury tort claim.
In the latter instance, settlements are, in a literal sense, “final and complete,” putting to rest, once and for all, a dispute between the parties (absent fraud or mutual mistake). Workers’ compensation, on the other hand, is social legislation, providing a measure of security to workers injured on the job, with the burden of that expense considered a proportionate part of the expense of production. The system endeavors fairly and fully to compensate the meritorious injury claim. Consequently, the Workers’ Compensation Act “permit[s] adjustment of the award in relation to facts subsequently appearing so as ‘to assure a compensation proportionate to the degree and duration of disability.”’
Franke v. Fabcon, Inc.,
Prior to 1992, Minnesota’s reopening provision, Minn.Stat. § 176.461 (1990), provided that an awаrd could be vacated “for cause,” and case law identified cause as fraud, mistake, newly discovered evidence and substantial change in employee’s condition.
Stewart v. Rahr Malting Co.,
Where settlements must conform to the law at the time of settlement, the law at the time of settlement applies for purposes of reopening awards.
Franke,
II.
The development of new facts about the injury after the award, or even the subsequent discovery of facts in exis
A mistake in diagnosis or extent of disability may also serve as grounds for reopening.
Stewart,
In view of the practical protective function of workers’ compensation, the desirability of preserving a right to reopen for genuine mistake seems too self-evident for argument. In the nature of things, there are bound to be mаny occasions when even the most thorough and skillful diagnosis misses some hidden compensable condition. Should the claimant then be penalized because of an erroneous disposition, either by award or settlement, when the only fault lies in the imperfections of medical science?
Larson & Larson,
supra,
§ 131.05(2)(b). Professor Larson believes the sounder apрroach is that in
Mattson v. Abate,
Monson asserts that based on newly discovered evidence, the failed L5-S1 fusion, there was a genuine and serious mutual mistake as to the nature and severity of his injury at the time of the settlement. "White Bear Mitsubishi/Wеstern National asserts there was neither newly discovered evidence nor a mutual mistake as to a material fact where the seriousness of Monson’s condition and the possibility that it could take a turn for the worse were clearly contemplated by the parties at the time of settlement. As we see it, although it was known that Monson had а serious back condition, it was not known that his persistent back pain had an objective and identifiable medical cause or that it would disable Mm from all work on a permanent basis. Instead, due to the difficulty in identifying the cause of Monson’s persistent pain, the medical records indicate that his “back pains had been attributed to that last refugе of the baffled diagnostician emotional instability.” Larson & Larson, supra, § 131.05(2)(b). Following a pain management program, Mon-son was referred for counseling and pool therapy.
Moreover, Monson was medically authorized to work fulltime subject to restrictions at the time of settlement. The settlement agreement reflects that both sides were operаting on the assumption that Monson was capable of substantial gainful employment: Monson was claiming retraining and economic recovery compensation, compensation payable when post-injury employment was unsuitable; and White Bear Mitsubishi/Western National was denying those claims, asserting that Monson
We therefore reverse the denial of the petition to vacate the award and remand fоr purposes of setting aside the award and granting a hearing.
Reversed and remanded.
Employee is awarded $1,200 in attorney fees.
Notes
. Although Monson was able to return to full-time employment, he did so at a significant wage loss, resulting in the payment of ongoing temporary partial disability compensation. Temporary partial disability compensation, paid at a rate of 66-2/3 percent of the difference bеtween pre- and post-injury wages, is essentially wage loss compensation.
Cassem v. Crenlo, Inc.,
. Under the law applicable to Monson’s injury, if the injured worker did not rеceive an offer of employment that was physically and economically suitable within 90 days of reaching maximum medical improvement, permanent partial disability benefits were payable as economic recovery compensation. Minn.Stat. § 176.101, subds. 3e(b), 3p (1990) (repealed 1995). If the employer did furnish such employment to the injured workеr, the worker received benefits payable as impairment compensation.
Id.,
subds. 3b, 3e(b) (1990) (repealed 1995). “Whether economic recovery benefits [were] owed rather than impairment compensation [made] a monetary difference.”
Cassem,
. We note that one source has explained in part: “Criteria for a successful fusion included no lucency or motion on plain radio-graрhs[.]” A. Ghanayem, M. Larson, & K. McDermott, The Effect of Pulsed Electromagnetic Fields on the Quality of Cage-Instrumented Lumbar Fusion in the Ovine Model, 47th Annual Meeting, Orthopaedic Research Society, February 25-28, 2001, San Francisco, California, available at http:// www.jbjs.org/ORS — 200 l/pdfs/0947.pdf (last visited May 29, 2003).
. The reopening provision applies to awards of compensation by settlement agreement, by determination by a compensation judge and denials of compensation.
E.g., Franke,