The self-insured employer appeals from the compensation judge’s finding that the employee’s work injury of September 20, 2007, is a substantial contributing cause of the employee's bilateral ankle problems and associated medical and surgical treatment.  The employer further appeals from the compensation judge’s award of permanent partial disability and temporary total disability benefits with interest.  We affirm the compensation judge’s decision with the exception of the award of permanent partial disability, which we vacate as premature.

The employee, Cheryl Lambert, began working for the employer, the Duluth Police Department, in 1990.  She worked as a patrol officer until about 1996, when she began doing office work and then worked as a community policing officer.  She was promoted to sergeant in 2000 and assigned to the major crimes division as a detective.  In 2003, she was assigned as a patrol sergeant, which involved patrol officer duties and supervision.  In 2004, the employee was trained to work as a police training supervisor, an activity she performed in addition to her regular duties.

The employee testified that during her employment as a police officer she had occasional ankle sprains; however, these strains all resolved fairly quickly.  The employee also noted that generally she wore police boots on the job which provided ankle support.  In April 2004, the employee was diagnosed with contusions and muscles strains to the left shin and right knee and a cervical strain after wrestling with a 250-pound suspect.  Her symptoms also included left ankle pain.  The employee testified that she did not recall the ankle problem continuing following initial treatment for this incident.

In May 2004, the employee was seen for a physical and a primary complaint of stomach problems.  In the history she provided for her doctor, she referred to other issues including right shoulder pain and hand swelling, pain on the soles of feet, swelling in her ankles, and right knee pain with the knee popping in and out.  She also described “periods where her ankles will swell for a day and then they will get better all of a sudden.”  She stated that she “has a history of very flexible joints.”  There was no history of prior ankle sprains.  The doctor thought she might have plantar fasciitis and “hyperflexibility syndrome.”

On May 7, 2007, the employee was seen by her chiropractor, Dr. Robert Torgrimson, for chronic neck and low back pain and arm numbness, which was worse after long shifts driving a patrol car.  The employee also mentioned that she had a history of ankle sprains.  There is no indication of treatment for her ankles at that time.

On September 20, 2007, the employee was assigned to speak and conduct presentations at an international police training conference being held at the Duluth Holiday Inn conference center.  The employee was not in patrol uniform for this conference and was wearing pumps rather than police boots.  As she was going down some stairs to the area in which the presentation was to be held, she lost her footing and fell.  She landed with both ankles twisted; she had bilateral ankle pain as well as pain in her right hip and flank.  Her colleagues at the conference assisted her into the conference area where she made her presentation.  She testified that she had to keep her right ankle elevated and iced for the rest of the day but managed to finish her work at the conference.

The employee’s symptoms continued to worsen over the next few days.  On September 22, 2007, she was seen at the Denfield Medical Clinic urgent care center by Dr. Lynn S. Quenemoen.  She reported having lost her footing two days before at a conference, fallen, and was complaining of right hip pain, pain in both ankles, and left flank pain.  Dr. Quenemoen noted mild swelling over the anterior talofibular ligament area on the right ankle, with no obvious bruising.  The left ankle showed no significant swelling or bruising.  Range of motion in the ankles and subtalar joints was full.  There was tenderness over the left flank without bruising.  X-rays taken of the right foot, ankle, and hip were read as showing no evidence of a fracture or dislocation, although the soft tissues along the lateral aspect of the foot and ankle were noted to be somewhat prominent.  The employee was advised to apply ice and use Advil or Tylenol.  She was placed on sedentary duty for two days.

The employee was seen by her chiropractor, Dr. Torgrimson, on September 24, 2007.  He noted that she had sustained a rather significant sprain to the right ankle and a less significant sprain to the left ankle.  She had multiple contusions on the knees, left arm, and an apparent right iliolumbar ligament sprain.  Dr. Torgrimson placed the employee on sedentary duty for the next two weeks.  He anticipated a good recovery from the iliolumbar sprain, but indicated in his chart notes that he was unsure if the employee could return to full duty at the end of that period of time with respect to the right ankle, which he stated was “quite unstable.”

Dr. Torgrimson authorized the employee’s return to light duty work on October 30, 2007, but continued to provide chiropractic treatment for her ankles based on her continued symptoms.

On November 20, 2007, Dr. Torgrimson noted that the employee’s range of cervical, thoracic, and lumbar spine motion was now within normal limits.  With respect to the ankles, he noted that the swelling was down and motion was also full.  He concluded that she could be released to work without restrictions as long as she wore her ankle brace as needed.

The employee testified that her ankles continued to swell frequently at work over the next year.  On some occasions she couldn't wear her police boots and would even wear tennis shoes and low cut socks to avoid loss of circulation from the swelling she was experiencing.  She also testified that her ankles would “roll” when she had been going up and down stairs, running, or traversing uneven ground.  The employee testified that she did not seek medical attention for this problem.

In January 2009, the employee began working as a sergeant of financial and property crimes, an office job rather than a patrol job.  However, she testified that her ankles would still continue to “roll” from time to time without any obvious reason.

The employee testified that in early September 2009 she was on duty and taking paperwork to the county courthouse for a signature to hold a suspect in custody.  She was in a hurry and ran part of the way; her ankle gave out and she fell.  She got up, felt embarrassed, and limped the rest of the way.  She did not see a doctor for this incident.

On September 11, 2009, the employee was off work and camping in Ely, Minnesota.  As she crossed a gravel road at the camp site, her left ankle gave out and she fell.  Her left ankle became sore and swollen.  She did not seek medical attention since she was planning to attend a wedding in Ely the next day.  She taped her ankle, iced it, and took Motrin.

The next day, September 12, 2009, the employee was about to go down some stairs near a church to take some photographs of the wedding party.  Her left ankle was still painful and sore.  Just as he was about to start down the steps, her right ankle rolled and “popped,” and she fell down the stairs.  Members of the wedding party assisted her in stabilizing the right ankle, icing it, and carried her into the church so that she could attend the wedding.

Later that day, the employee was seen at the emergency room at the Ely Bloomenson Community Hospital by Dr. John W. Knott.  Swelling was noted in the right ankle radiating into the foot, with tenderness over the right foot.  An x-ray of the right foot and ankle showed no fracture or focal soft tissue swelling; there were mild mid foot degenerative changes suggestive of an old injury.  Dr. Knott suggested ice, elevation, and partial weight bearing.

On September 14, 2009, the employee sought treatment at Orthopaedic Associates of Duluth where she was seen by Dr. Benjamin Clair.  The employee complained of bilateral ankle sprains and instability.  She noted that she had experienced chronic problems with spraining her ankles with over eight sprains on either side.  The most recent were to the left ankle while camping and to the right ankle while attending a wedding, both having occurred on the past weekend, and which had given rise to symptoms the employee was “familiar with.”  The employee reported that she had been treating with Ace wraps, icing, and oral pain medications.  She noted that she had been spraining her ankles since she was a teenager.  She had tried braces and treatments in the past which provided some benefit, but she did not feel she could continue to function with bracing alone.

On examination, both ankles were tender in and about the calcaneal fibular and anterior talofibular ligaments.  The employee could invert more significantly than evert at the left lower extremity.  She had plantar pain in and about the plantar fascial insertion on the left side.  The right ankle was mildly swollen.  There was an inversion bias to the heel both on non-weight bearing and weight bearing.  She had primary inversion of motion at the subtalar joint.  Inversion of the right forefoot gave significant pain in and about the anterior talofibular ligament.  Swelling about the right lateral ankle was 2+.  The employee had a cavus foot structure bilaterally.  X-rays showed no fracture, dislocation, or subluxation.  Dr. Clair’s impression was of bilateral ankle instability, right greater than left.  An MRI was ordered of both ankles to evaluate articular pathology, the lateral ligamentous complex and possible tendinous injuries.  The employee was put on work restrictions.

The MRI views were performed on September 15.  That of the left ankle was read as showing limited tenosynovitis at the peroneus brevis and longus tendons.  A small ganglion cyst was noted.  The ligaments appeared intact.  The MRI of the right ankle showed an abnormally indistinct anterior talofibular ligament consistent with disruption or partial disruption.  There was degenerative narrowing between the distal fibula and adjoining talus with early degenerative irregularity of the distal fibula.  A moderate sized ankle joint effusion and a small subtalar joint effusion were present.

The employee was seen again by Dr. Clair on October 7, 2009.  She continued to report right ankle instability.  The left foot and ankle were unchanged.  Dr. Clair recommended right ankle arthroscopy and ligamentous repair.  The employee elected to proceed with surgical treatment and Dr. Clair performed surgery on October 22, 2009.  Surgical findings included mild synovitis in the anterior aspect of the right ankle.  Cartilaginous surfaces were intact without significant defect or deformity.  There was significant instability of the lateral ligamentous ankle complex with significant inversion.

The employee experienced significant improvement with the surgery, and her right ankle showed significantly improved stability on inversion testing compared to preoperative evaluations.  On January 22, 2010, when seen in follow-up by Dr. Clair, the employee noted that her left ankle was showing more symptoms of instability.  Dr. Clair found inversion beyond the normal range of motion accompanied by tenderness about the distal calcaneofibular and anterior talofibular ligament.  There was ankle joint line tenderness on the anterior margins.  The doctor recommended that the employee undergo surgery on the left ankle.

The employee underwent the surgery on February 18, 2010, in the form of a left ankle arthroscopy with synovectomy; lateral ankle biligamentous collateral ligment repair, and posterior splint application.  Significant instability about the lateral ankle with inversion beyond the normal range was noted at the time of surgery and there was a deficiency with evidence of tearing at the area of the calcaneofibular ligament.  The ankle articular cartilage appeared intact with mild chronic anterior ankle synovitis.  The employee noted left ankle improvement as a result of this surgery.

In a report dated April 15, 2010, Dr. Clair stated “In response to whether or not I believe with a reasonable degree of medical certainty that the injury on September 20, 2007, was probably a substantial contributing factor leading to the conditions that were described in the letter - I do believe that the injury sustained is related to the ankle instability situation that I saw, evaluated and treated the employee surgically for.”  He considered the MRI and arthroscopy findings supported a diagnosis of chronic ankle instability resulting from an acute inversion ankle sprain.

On May 3, 2010, Dr. Clair released the employee to work full duty as she was able to tolerate.

The employee was seen by Dr. Nolan Segal on September 1, 2010, for an examination on behalf of the self-insured employer.  The employee's current symptoms were ankle soreness at the end of her work day for which she was taking Tylenol.  She was able to walk on her toes and heels with no visible lower extremity weakness.  There was slight ankle discomfort during toe walking, but none when walking on heels.  The employee was noted to have cavus feet bilaterally.  Tibiotalar, subtalar, and mid and forefoot motion was full and there was no crepitus in either ankle.  Ankle ligaments were stable in all planes.  No swelling was noted.  Muscle strength, reflexes and sensation were normal in both legs.  Dr. Segal concluded that the employee's history of ankle strains probably resulted from generalized joint hyper flexibility, perhaps developmental in origin.  He did not believe that the employee's examination findings following the 2007 work injury were consistent with having sustained significant damage to the ankle ligaments.  In his view, that injury was not a substantial contributing factor to the employee's right or left ankle injuries in September 2009 or to the conditions treated surgically by Dr. Clair.  He considered the employee capable of working without restrictions and concluded that she had not sustained any permanent partial disability.

On December 14, 2010, Dr. Clair rated the employee with two percent plus one percent for each ankle pursuant to Minn. R. 5223.0520, subparts 4a and 4b.  He noted that the rating would have been higher if her condition had not been addressed surgically.  Dr. Clair noted that there was still some functional loss in regard to ankle plantar flexion, dorsiflexion, inversion, and eversion.

In a letter dated January 6, 2011, Dr. Segal disagreed with Dr. Clair’s rating and reiterated his opinion that the employee had no ratable permanency.

A hearing was held on January 21, 2011, before Compensation Judge Jerome Arnold.  In his decision of March 7, 2011, he found that the employee's work injury of September 20, 2007, was a substantial contributing cause of the employee's bilateral ankle problems and associated medical and surgical treatment, and awarded temporary total disability, with interest, for periods the employee was off work from the surgery.  The judge also awarded permanent partial disability in accordance with the opinion of Dr. Clair.  The self-insured employer appeals.

At the hearing below, the self-insured employer relied on the opinion of their medical expert, Dr. Segal, and on the medical records, which they contend contradict the employee's testimony that she continued to experience ankle symptoms following initial treatment for the 2007 work injury.  In addition, the employer argues that the evidence suggests the employee had a significant prior history of ankle instability, given that she admitted having sprained or turned her ankle on occasions going back to high school.  They further argue that her 2007 work injury resolved quickly, pointing to the fact that the employee did not go to the emergency room after her work injury and did not seek any treatment for several days, and that her examination findings were “minimal” when she did seek treatment.  Finally, they contend, the evidence taken as a whole supports their view that the employee’s work injury did not substantially contribute to a worsening of such ankle instability and that the employee’s preexisting condition coupled with the effects of the 2009 non-work injuries were the sole factors contributing to her need for bilateral ankle surgery.

The compensation judge, on the other hand, reached a different conclusion from the evidence and found that the September 20, 2007, work injury was a substantial contributing factor to the employee’s need for right ankle surgery in October 2009 and left ankle surgery in February 2010.  In reaching this finding, the judge relied not only on the medical records, but also significantly relied on the employee's testimony of continuing symptoms, which he found credible, and on the expert medical opinion of Dr. Clair, which he adopted over the contrary opinion of Dr. Segal.  The question for our review is not whether the evidence could have supported an interpretation consistent with that proposed by the appellant, but whether substantial evidence supported the judge’s finding.

The employer contends that the compensation judge should not have relied on the employee’s testimony, arguing that the testimony was unreliable because the employee was not “forthcoming” about her prior medical history.  To illustrate this claim, the employer notes that, with the exception of a single incident playing tennis in high school, the employee denied having ever sprained or “rolled” her ankles outside of work until 2009.  The employer argues that it is “difficult to believe” that the employee had not experienced ankle problems away from work as well as at work.

The actual testimony by the employee, however, was that while she had experienced some ankle problems away from work, none were as significant or memorable as either the 2007 work injury or the later off work 2009 incident, or as several unreported work incidents between those dates and about which she specifically testified.  Whether or not the employer found the employee's testimony “difficult to believe,” the compensation judge apparently did believe her and expressly concluded that the testimony was credible.  Assessment of the credibility of a witness is the unique function of the trier of fact and will not be overturned by this court unless clearly erroneous.  Even v. Kraft, Inc., 445 N.W.2d 831, 835, 43 W.C.D. 220, 225 (Minn. 1989); Brennan v. Joseph G. Brennan, M.D., P.A., 425 N.W.2d 837, 839-40, 41 W.C.D. 79, 82 (Minn. 1988).

The employer also contends that, as a matter of law, the employee’s testimony that she injured both her ankles in the 2007 work injury should have been “disregarded as without evidentiary value.”  In support of this contention, the employer cites Turay v. Allied Enters., Inc., 256 N.W.2d 71, 29 W.C.D. 561 (Minn. 1977) and Storkamp v. DBL Labs, Inc., slip op. (W.C.C.A. April 19, 1995), a case citing Turay, for the proposition that “physical facts which speak the truth unerringly cannot be overcome by oral testimony.”

In Turay, an employee’s later testimony as to which knee had been struck by a winch during a work injury was contradicted by x-ray images taken a few days after the injury which clearly showed the other knee had been treated.  The employer argues that the medical records in this case similarly directly contradict the employee’s testimony that she injured both ankles.  We disagree.  The records of Dr. Quenemoen made two days after the work injury recite that the employee reported pain in both ankles; both ankles were examined, and x-rays were taken of each.  Similarly, on September 24, four days after the accident, the employee was seen by her chiropractor, Dr. Torgrimson, who diagnosed a significant sprain to the right ankle and a less significant sprain to the left ankle.  There is nothing in the medical records that rises to the level of an “unerring physical fact” in contradiction to the employee’s testimony.  For reasons similar to those expressed in Storkamp, supra, we distinguish the factual setting of Turay from that presented here.

As we have noted, the employee relied on the opinion of Dr. Clair to establish causation.  That opinion was accepted by the compensation judge.  Where there is adequate foundation for the opinion adopted by the judge, this court must uphold the compensation judge’s choice among medical experts.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  The employer does not argue that Dr. Clair’s opinion was without sufficient foundation.  Instead, the employer asserts that the wording of that opinion failed to meet the standard of reasonable medical certainty.  Dr. Clair’s opinion was phrased as follows:

In Pommeranz v. State, Dep’t of Public Welfare, the Minnesota Supreme Court discussed the requisite certainty for demonstrating causation by expert medical opinion in a workers’ compensation case, noting that “[i]t is well established that a medical opinion does not have to express absolute certainty, its truth need not be capable of demonstration, and it is sufficient if it is probably true.”  261 N.W.2d 90, 91, 30 W.C.D. 174, 176-177 (Minn. 1977).  We conclude Dr. Clair’s opinion had the necessary medical certainty and could be relied upon by the compensation judge.

Based on our analysis of the foregoing points, we conclude that the compensation judge's finding as to causation was supported by substantial evidence, and should be affirmed.

The self-insured employer, however, contends that, whether or not there was substantial evidence to support the finding, the finding must be reversed because the compensation judge made factual errors and omissions in assessing the record and in reaching his findings.  To support the claim that evidence was omitted or disregarded, the employer itemizes in its brief a long list of facts which it states were not discussed by the compensation judge.  We note, however, that the fact that the compensation judge did not recite or refer to all evidence in his findings does not establish that he overlooked that evidence.  See, e.g., Rothwell v. State, Dep’t of Natural Resources, slip op. (W.C.C.A. Dec. 6, 1993); Pelto v. USX Corp., slip op. (W.C.C.A. Dec. 16, 1993).  A compensation judge is not required to relate or discuss every piece of evidence introduced at trial. Witry v. Sacred Heart Church, No. WC09-118 (W.C.C.A. Aug. 24, 2009).

To suggest that factual errors were made, the employer also quotes several specific findings where the compensation judge summarized parts of the record and used a different phrasing than was found in the portions of the record being summarized.  We have reviewed the instances provided in the employer’s brief and are fully satisfied that the compensation judge’'s phrasing in summary of the evidence is not materially at variance with that evidence, but instead fairly summarizes that evidence and reaches factual conclusions consistent with the judge's role as finder of fact.

Finally, the employer argues that the finding on causation is legally insufficient because the judge did not provide a discussion of various factors which this court has previously noted may be considered in determining whether a work injury resulted in a permanent aggravation of a pre-existing condition.  The factors are those listed in McClellan v. Up North Plastics, slip op. (W.C.C.A. Oct. 18, 1994).

We note, first, that the employer’s argument presupposes that the employee’s work injury is properly analyzed in the context of a pre-existing condition and aggravation.  While it was the employer’s theory of the case, based on Dr. Segal’s opinion, that the employee’s work injury was a temporary aggravation to a generalized joint hyperflexibility syndrome, we note that the compensation judge did not make any findings of a pre-existing condition of this kind, and, in fact, rejected Dr. Segal’s expert medical opinion in favor of the opinion of Dr. Clair, who seems to have viewed the 2007 work injury not as an aggravation to some pre-existing condition, but as a single, discrete injury in the form of bilateral acute inversion sprains.  And, we have previously held that use of the McClellan factors is not mandatory, even in aggravating injury cases.  See, e.g. Calbillo v. MG Waldrum, No. WC05-235 (W.C.C.A. Jan. 31, 2006).  We therefore conclude that the judge's failure to address the McClellan factors is not a basis for reversal in this case.

The compensation judge's finding on causation is affirmed.

The employee's claim petition sought temporary total disability compensation [TTD] for periods during when the employee was off work as a result of her ankle conditions and surgery.  During the hearing, the compensation judge requested clarification from the employee and counsel on whether the employee had been paid leave in lieu of compensation for those periods.

The compensation judge awarded wage loss benefits for the periods from October 22, 2009 - January 24, 2010 and from February 18, 2010 - May 2, 2010.  The self-insured employer contends that the judge’s inquiry at the hearing, relevant portions of which are quoted above, constituted a stipulation by the parties that the employee was paid leave in lieu of compensation and that the judge was to specifically order an offsetting credit against any award of temporary total disability compensation.  The employer contends that the award of TTD here must be modified or reversed in order to avoid double compensation to the employee.

We disagree.  The parties litigated this case primarily with respect to the question of primary liability.  The employee generally acknowledged having been paid leave for some periods, but not others.  The judge was not provided with evidence by which to determine the specific dates and extent to which the employee had been paid sick leave during the same periods.  Under the issues and evidence before him, the compensation judge’s responsibility in this matter was to determine the employee’s eligibility for workers’ compensation benefits, and he was not required to calculate sick leave payments or determine how those should be reclassified and applied against benefits owed.  Liability having been established and benefits awarded, the parties presumably can determine when and in what amounts sick leave was paid during periods in which the employee was found eligible for TTD.

The self-insured employer also objects to the award of interest, asserting that the compensation judge should have found that payment of sick leave benefits for some or all parts of the same periods for which TTD compensation was payable rendered an award of interest inappropriate.  We note, however, that it was not clear that sick leave was in fact paid by the employer for all periods of TTD, and that, under the plain language of Minn. Stat. § 176.221, subd. 7, an award of interest on any payment of compensation “not made when due” is mandatory and not discretionary.  We conclude that the compensation judge did not err in including an order for an award of interest.

The employee’s claim petition did not allege permanent partial disability.  However, about a month prior to the hearing in this matter, presumably with a hope of resolving all the employee’s potential claims at one hearing, the employee’s attorney requested that Dr. Clair provide an opinion about the extent of any permanent partial disability the employee had sustained from the 2007 work injury.  In his letter to Dr. Clair, he noted that providing this opinion might require that the doctor reexamine the employee, and that he would be glad to try to expedite that.

In a letter dated December 14, 2010, Dr. Clair replied that he had gone ahead and reviewed the employee’s loss of function “based upon previous encounters and functional assessment,” although he also noted his understanding that, since last seen, the employee “has returned to work and has continued to improve functionally.”  Dr. Clair rated each ankle with two percent permanent partial disability, citing Minn. R. 5223.0520, subp. 4.A.  He rated an additional one percent for each ankle under Minn. R 5223.0520, subp. 4.B.  Dr. Clair did not provide the specific measurements on which he based these ratings.

The primary issue at the hearing was one of causation.  In opening statements, the defense did not even address the permanency claim, although they did offer evidence offered in defense of that claim in the form of a supplementary letter report from Dr. Segal, who disagreed with Dr. Clair's rating and opined that the employee’s condition did not warrant any permanent partial disability under the schedules.

The compensation judge adopted Dr. Clair’s rating, but in the absence of specific, recent examination findings was unable to determine exactly which provisions in the rule on which the doctor relied in reaching that rating.^[1]

The self-insured employer objects on appeal to the compensation judge’s permanency rating as premature.  We agree.

Where the employee had not seen Dr. Clair for six months and apparently had continued to improve since that time, a determination of permanency should not have been based solely on the doctor’s prior examination findings.  The finding as to permanency is, therefore, vacated.  The employee remains free to raise the issue of permanency in the future where based on a subsequent medical opinion predicated on more recent detailed examination findings that might support a rating under the disability schedules.