The employee petitions to vacate a Findings and Order, served and filed June 19, 2006, on the grounds of mistake and/or newly discovered evidence.  Concluding the employee has established good cause, we grant the petition.

Robert E. Battle, the employee, worked as a courier for the self-insured employer, Federal Express Corporation.  On March 15, 2005, the employee fell between the back of a truck and the loading dock, hitting his right leg and knee on the dock plate.  The employee sought treatment at urgent care on March 20th for a large contusion on the upper right lateral lower leg.  Dr. Martha Hickner noted a cyst-sized swollen area just below the knee, and healing skin extending above the knee about four inches and below the knee about six inches.  The doctor diagnosed a large hematoma with secondary cellulitis,^[1] prescribed an antibiotic and pain medication, and advised the employee to stay off and elevate the leg.  The employer accepted liability for the injury, paying wage loss benefits and medical expenses.

The employee was seen in the emergency room at Regions Hospital on March 25, 2005, for worsening right leg pain.  Two areas of injury were noted: one on the right lateral thigh consistent with a healed abrasion, and one on the medial aspect of his lower knee which was  infected.  An ultrasound revealed a complex large abscess, and a physician from the trauma and acute care surgery clinic (TACS) was called in to incise, drain and pack the wound.  The employee was taken off work and instructed to keep the leg elevated as much as possible.

The employee was seen in follow-up visits by various TACS physicians, including Dr. Michael McGonigal, over the next two months.  On June 3, 2005,  Dr. McGonigal noted the wound was well healed, and he released the employee to return to work on June 14, 2005, with no restrictions.  On August 16, 2005, Dr. McGonigal completed a health care provider report indicating the employee had reached maximum medical improvement on June 14, 2005, for a contusion and cellulitis of the right leg.

The employee returned to Dr. McGonigal for a final visit on September 2, 2005.  The employee reported, with his return to work and increased ambulation, he had noted anterior knee pain and a feeling of giving way in the knee.  The doctor ordered an x-ray of the knee, and referred the employee to Dr. Bruce Levy, an orthopedic surgeon.

The employee was seen by Dr. Levy on October 10, 2005.  The doctor noted the employee continued to have a great deal of pain on the medial side of his knee, particularly at the end of the day, as well as episodes of knee locking or buckling.  On exam, the doctor noted a slightly antalgic gait, no effusion of the right knee, and a significant amount of pain along the medial joint line and mild tenderness along the lateral joint line.  Dr. Levy assessed a likely right knee medial meniscus tear, and ordered an MRI scan.  The October 18, 2005, scan was interpreted by the radiologist as unremarkable except for moderate thinning and mild surface irregularities on a portion of the medial retropatellar cartilage, with no evidence of a meniscal tear or ligament injury.  Dr. Levy, however, separately reviewed the MRI study, concluded there was evidence of a posterior horn meniscal tear, and recommended right knee arthroscopic surgery.  The doctor opined the March 15, 2005, incident caused the medial meniscal tear.

The employee was examined on December 22, 2005, by Dr. David Fey, an orthopedic surgeon, at the request of the self-insured employer.  The employee complained of persistent posterior/anterior and lateral right knee pain, that increased with activity.  On examination, the doctor noted tenderness about the medial, lateral and posterior knee and some slight crepitance about the patellofemoral joint.  Dr. Fey concluded the employee’s history and examination were highly inconsistent with a meniscal tear, and opined the employee’s diagnosis was degenerative arthritis of the right patellofemoral joint.  The doctor maintained the employee’s right knee condition resulted from the normal progression of patellofemoral degenerative changes and was in no way related to the work injury of March 15, 2005.  Dr. Fey further recommended against the proposed arthroscopic surgery, stating the employee would not benefit from a partial medial meniscectomy.

Based on Dr. Fey’s report, the self-insured employer served a notice of intention to discontinue temporary total disability benefits effective January 5, 2006.  The employee, in turn, filed an objection to discontinuance and a medical request seeking payment of medical bills and approval for the surgery recommended by Dr. Levy.  The case was heard by a compensation judge on May 3, 2006.  In a Findings and Order filed on June 19, 2006, the compensation judge adopted the opinions of Dr. Fey: that “the employee’s current right knee condition is patellofemoral degenerative changes with diffuse right knee pain;” that “the employee’s current knee condition of degenerative arthritis of the patellofemoral joint would be related to the natural progression of this condition;” and that “the employee’s current diagnosis is not related to the work injury of March 15, 2005.” (Finding 12.)  The judge specifically rejected Dr. Levy’s diagnosis of a posterior horn meniscal tear (Finding 13).

In the meantime, the employee underwent right knee arthroscopic surgery on June 8, 2006, performed by Dr. Levy.  The doctor found a previously undiagnosed unstable cartilaginous flap on the lateral femoral condyle with grade II-III chondromalacia.  There was no medial or lateral meniscus tear.^[2]  In subsequent reports, Dr. Levy stated there was no evidence of any degenerative osteoarthritis at the time of the arthroscopy.  Rather, the employee had an acute, traumatic cartilage defect and chondromalacia, also traumatic in nature, that, in his opinion was causally related to the employee’s March 15, 2005, work injury.

In a supplemental report dated February 14, 2007, Dr. Fey agreed the employee’s knee condition was an unstable cartilaginous flap involving the lateral femoral condyle.  The doctor stated, however, that the mechanism of injury, which he described as “scraping his tibia,” was not consistent with an injury that would result in intraarticular pathology, and opined that the employee did not sustain an injury to the right knee in the March 15, 2005, incident.  In Dr. Fey’s opinion, the most reasonable explanation was that the employee’s condition was the result of a previous injury to the right knee, at work, on November 26, 1999.

The employee filed a petition seeking to vacate and set aside the June 19, 2006, Findings and Order on the grounds of a mutual mistake of fact and/or newly discovered evidence relating to the employee’s knee condition.  The self-insured employer objects.

For awards issued after July 1, 1992, “cause” to vacate includes a mutual mistake of fact or newly discovered evidence.  Minn. Stat. § 176.461(1) and (2).  There is no dispute, based on the post-hearing arthroscopic surgery findings, that both Dr. Levy and Dr. Fey were mistaken in their diagnoses of the employee’s right knee condition.  Moreover, the self-insured employer concedes that both a mutual mistake of fact and newly discovered evidence exist in the present case.  (Er Brief at 6.)

In Monson v. White Bear Mitsubishi, 663 N.W.2d 534, 63 W.C.D. 337 (Minn. 2003), the Supreme Court held “[t]he development of new facts about the injury after the award, or even the subsequent discovery of facts in existence but unknown at the time the award was made, is sufficient to justify the vacation of an award,” and, more specifically, that a mistake in diagnosis may serve as grounds for reopening an award.  Id. at 539-40, 63 W.C.D. at 344; compare, e.g., Peterson v. Bullyan Mobile Homes, No. WC04-196 (W.C.C.A. Feb. 23, 2005).  The self-insured employer, however, argues the mistake in diagnosis was not material or relevant to the compensation judge’s decision on causation, and the petition to vacate should be denied.  We disagree.

The principal controversy at the time of the hearing was the nature of the employee’s injury.  The employee relied on Dr. Levy’s opinion, based on his diagnosis of a meniscal tear, that the employee sustained an injury to his right knee as a result of the March 15, 2005, incident.  The self-insured employer maintained, based on Dr. Fey’s opinion, that the employee’s right knee condition was patellofemoral osteoarthritis, a degenerative process not related to the admitted work injury.  The compensation judge adopted Dr. Fey’s opinion in determining the employee did not sustain a work-related right knee injury, a conclusion that is clearly based on and dependent upon Dr. Fey’s diagnosis.  Post-surgery, based on the change in diagnosis, both parties now advance causation theories significantly different from those litigated at the May 3, 2006, hearing.

This court generally has broad discretion in determining whether to vacate an award.  Krebsbach v. Lake Lillian Coop. Creamery Ass’n, 350 N.W.2d 349, 36 W.C.D. 796 (Minn. 1984).  The Supreme Court has noted that fundamental fairness is the overriding principle for determining whether an award should be set aside.  Id.; Landon v. Donovan Constr. Co., 270 N.W.2d 15, 31 W.C.D. 135 (Minn. 1978); Wollschlager v. Standard Constr. Co., 300 Minn. 550, 220 N.W.2d 346, 27 W.C.D. 495 (1974).  Based on the post-hearing surgical findings, the parties agree the pre-operative diagnoses of both Dr. Levy and Dr. Fey were mistaken.  As a result, the medical opinions upon which the case was litigated were flawed.  Causation for the employee’s right knee injury, based upon the actual diagnosis of his condition, was not presented or considered at the May 3, 2006, hearing.  We, therefore, conclude the employee has established good cause sufficient to vacate the compensation judge’s findings and order.^[3]