Archer Daniels Midland, Inc. v. Robert Warren ( 2015 )


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  •                     IN THE COURT OF APPEALS OF IOWA
    No. 14-0956
    Filed April 22, 2015
    ARCHER DANIELS MIDLAND, INC.,
    Plaintiff-Appellant,
    vs.
    ROBERT WARREN,
    Defendant-Appellee.
    ________________________________________________________________
    Appeal from the Iowa District Court for Polk County, Richard G. Blane II,
    Judge.
    An employer appeals from the judicial review decision affirming the
    workers’ compensation commissioner’s award of permanent total disability
    benefits to Robert Warren. AFFIRMED.
    Jordan A. Kaplan and Mark A. Woollums of Betty, Neuman & McMahon,
    P.L.C., Davenport, for appellant.
    Bob Rush of Rush & Nicholson, P.L.C., Cedar Rapids, for appellee.
    Heard by Vogel, P.J., and Potterfield and Mullins, JJ.
    2
    POTTERFIELD, J.
    Archer Daniels Midlands, Inc. (ADM) appeals from the judicial review
    decision affirming the workers’ compensation commissioner’s award of
    permanent total disability benefits to Robert Warren. On appeal, ADM contends
    the district court erred in failing to remand this case to the commissioner for
    reevaluation after the district court found one physician’s opinion of causation
    was a “nullity,” and argues the causation determination in the absence of that
    opinion is not supported by substantial evidence. ADM also maintains Warren’s
    pre-injury-date retirement plans—as a matter of law—preclude an award of
    permanent total disability.
    Because the commissioner weighed the expert opinion evidence
    thoroughly and documented its finding of causation, and the district court
    accepted the finding of the commissioner as supported by substantial evidence in
    the record, we affirm the causation finding.      Additionally, we do not find the
    commissioner’s determination as to industrial disability was irrational, illogical, or
    wholly unjustifiable. We therefore affirm the district court’s decision affirming the
    Iowa Workers’ Compensation Commissioner’s award of permanent total disability
    benefits to Warren.
    I. Background Facts and Proceedings.
    Evidence at the arbitration hearing established Warren was born in
    February 1949, completed the ninth grade, and later obtained his G.E.D. He
    attended Kirkwood Community College and earned diplomas or certificates in
    welding, blueprint reading, and pipe fitting. In 1969, Warren suffered a severe,
    traumatic right-hip injury after falling twenty-eight feet from a roof that collapsed.
    3
    The fall resulted in a comminuted fracture of the intertrochanteric area of the right
    femur and fractures to the olecranon. Warren underwent a Jewett hip nailing
    procedure involving a three and one-half inch nail, a four inch plate, and metallic
    screws.
    Warren worked as a welder from 1974 until 1986 when that employer’s
    plant closed. From 1975 to 1976, Warren had complained of pain in the right hip
    and had an x-ray showing “some motion about the Jewett nail.” At his doctor’s
    recommendation, Warren had the Jewett nail removed. On February 27, 1976,
    Dr. J. Huey noted Warren’s leg was well healed and released him to return to
    work. In 1980, Warren was seen once for left hip pain. Dr. Huey noted leg
    lengths were equal and commented “[h]is right hip has an old varus deformity
    from a fracture but it looks pretty good, really. It has healed solidly and the head
    is viable. The left hip reveals no evidence of degenerative arthritic change.”
    Warren worked for a different employer’s manufacturing business from 1987 to
    2000. He then drove a semi-truck for about six months.
    On March 19, 2001, Warren began working for ADM. His health was
    “excellent” when he started and he was under no restrictions. He worked for six
    months in a warehouse moving and stacking bags. From there, he moved to his
    permanent job—refinery utility. As a utility worker, Warren was responsible for
    moving railcars (preparing them to carry corn syrup) and directing trucks into
    proper filling position. Warren’s position included twelve- to sixteen-hour work
    days, lifting up to one hundred pounds much of that time. His work “was heavy,
    physical labor that required walking on uneven ground, standing, crawling,
    stooping, climbing onto and into and out of railcars, climbing steps, bending,
    4
    twisting, lifting, and pulling, amongst other strenuous physical acts.”   He fell
    several times on the uneven rail yard terrain.
    Warren’s right hip began to bother him when the rail car staging area was
    expanded, which caused him to walk more.         He was taking ibuprofen and
    Tylenol, but these over-the-counter medications provided only limited relief. On
    January 28, 2009, Warren went to his family doctor, Dr. Yang Ahn, complaining
    of stiffness and pain. A prescription painkiller was prescribed. Pain in his hip
    was noted on an April 22, 2009 visit.
    Warren’s symptoms worsened and Dr. Ahn referred him to Dr. Michael
    Brooks for evaluation on July 31, 2009. Dr. Brooks’ recorded history included a
    progressively worsening condition. The prescribed painkiller initially helped but
    eventually provided only moderate relief. Warren’s employment was described
    as “a manual position loading and preparing railroad cars for corn syrup.” Dr.
    Brooks assessed “[p]olyarthritis with a predominance of osteoarthritis.” He gave
    Warren a steroid injection and prescribed a different painkiller. Dr. Brooks also
    ordered additional lab studies. On November 5, 2009, Dr. Brooks noted the lab
    studies “did not corroborate any systemic inflammation.” Dr. Brooks indicated
    the new medications were providing “good overall pain response . . . but [Warren]
    continues to have significant arthralgias and myalgias in the arms and in the
    legs.” Dr. Brooks concluded, “I’ve discussed the nature of his disease and the
    limits of our ability to treat at this point and have suggested he continue
    symptomatic control.”
    Warren returned to Dr. Brooks on May 5, 2010, reporting “significant
    symptoms of pain, stiffness and chronic fatigue with myalgias” and “problems
    5
    with right hip pain and stiffness.” Additional pain medication was prescribed. Dr.
    Brooks noted, “I’ve discussed the possibility of sending him to one of the
    orthopedic surgeons but he’s not anxious to consider that at the present time.
    We will monitor his response to these changes and see him back in 4-6 months.”
    The notes from a September 15, 2010 visit with Dr. Brooks include:
    [Warren] continues having symptoms of more diffuse arthralgias
    and myalgias are really more a predominance of pain in the right
    pelvic area down the right thigh. This is worse with walking on
    uneven ground and with weightbearing. He does have an antalgic
    gait when the symptoms become worse and he indicates that the
    symptoms are somewhat waxing and waning in terms of severity.
    ....
    We discussed the possibility of a total hip arthroplasty at
    length today. I reviewed with him the results of the x-ray and
    suggested that his hip pain is unlikely to get better unless
    something is done more definitively. He has multiple questions
    regarding his job situation if he does have the hip replaced and I
    answered those to the best of my ability but recommended that he
    at least have a consultation with one of the orthopedic surgeons to
    discuss the situation as well. He is thinking about that option at this
    point.
    On September 22, 2010, Warren saw Dr. Sandeep Munjal, an orthopedic
    surgeon. Dr. Munjal noted, “His work does require significant lifting of loads and
    more than twelve hundred steps a day of rough walking.” X-rays demonstrated
    “advanced degenerative changes in the right hip with hallmarks of previous
    surgery and a valgus alignment of the hip.” Physical examination revealed a
    painful right hip, limping, and antalgic gait. Dr. Munjal assessed osteoarthritis of
    the right hip and “unexplained poly inflammatory arthropathy.”           Dr. Munjal
    “discussed hip replacement in great detail with the patient.”
    Obviously there will be significant concerns regarding his job with
    especially the high amount of loading he has to do. I discussed hip
    replacement in great detail with the patient, including restrictions
    associated with that.       He is thinking about surgery in
    6
    February/March prior to his retirement. Activity modifications after
    that.
    On January 12, 2011, Warren returned to see Dr. Brooks and reported he
    was scheduled to have right hip joint replacement. “He is aware that he will not
    be able to continue his present job after the surgery due to the requirements of
    lifting, squatting and climbing associated with his present job.” Dr. Brooks wrote
    further,
    I reviewed the situation with him and have elected to have
    him continue the meloxicam and call me with a report in terms of
    what exactly he’s been doing with the tramadol before deciding on
    further pain medications. I like to get him through the surgery and
    off of work for a month or two prior to considering more medications
    and would therefore like to see him back again in about four
    months for reevaluation and assessment of what medications
    would make sense in his new situation after the surgery.
    Warren underwent a right total hip replacement on February 22, 2011. On
    May 11, 2011, Dr. Munjal examined Warren and discussed returning to work:
    Regarding return to work, we gave him a return to work slip when
    FMLA is up May 17 with normal restrictions [fifty-pound weight limit;
    the restrictions also included no bending, climbing, crawling,
    kneeling, stooping, twisting or stair steps]. He will let us know if he
    needs anything additional to this . . . . The patient was encouraged
    to resume activities as tolerated. We will see the patient back at
    one year from the time of surgery or sooner if problems.
    On May 13, 2011, Warren was seen for follow-up by Dr. Brooks. Dr.
    Brooks noted Warren “is recovering from [hip replacement] quite nicely although
    he is still very restricted in terms of his activities and it is clear that he is not going
    to be able to go back to work in his previous position because of the restrictions.”
    Warren returned to ADM, but was told his restrictions could not be
    7
    accommodated. Consequently, Warren’s last date of employment with ADM was
    February 18, 2011.1
    On April 5, 2011, Warren filed a petition seeking workers’ compensation
    benefits for a cumulative injury. ADM sent Warren for an independent medical
    examination (IME) with Dr. William Boulden on June 15, 2011. In his report, Dr.
    Boulden opined “Warren’s work activities with Archer Daniels Midland . . . did not
    accelerate or cause the osteoarthritis of his hip, for which he had the hip
    replacement.” He also wrote,
    I believe Dr. Munjal’s letter dated Febraury 11, 2010, basically
    states what I have stated; that the arthritis was not caused by the
    patient’s work. The patient did physical activities at work and he
    states that the patent’s symptoms may have been aggravated by
    his work, but once again, the arthritis was the cause of the
    operation and the pain is from the arthritis.
    On March 13, 2012, Warren was seen by Dr. Ray Miller for another IME.
    Dr. Miller wrote:
    It is my opinion from evaluating Mr. Warren, his medical records,
    and his job requirements, that his work activity during his ten years
    at Archer Daniels Midland were significant physical activities that
    contributed to the progression of osteoarthritis resulting in the need
    for a total hip replacement. Those work requirements accelerated
    the osteoarthritis and the need for a hip replacement.
    On March 19, 2012, Dr. Munjal signed off on a letter from ADM’s attorney
    agreeing with Dr. Boulden that Warren’s “symptoms may have been aggravated
    by his work, but once again, the arthritis was the cause of the operation and the
    pain is from the arthritis.” On May 4, 2012, Dr. Munjal signed his name to a letter
    from Warren’s attorney indicating he agreed with Dr. Miller that Warren’s
    employment with ADM accelerated his right hip arthritis causing the need for the
    1
    Warren was later found to be totally disabled for Social Security disability purposes.
    8
    total hip replacement. At a June 11, 2012 deposition, Dr. Munjal testified that
    Warren’s work activities were not a cause of Warren’s osteoarthritis. After being
    told the difference in the definition of probability and possibility, Dr. Munjal said “it
    is probable the increased pain was caused by lifting and all the work. Regarding
    arthritis, I would say possible because—or it’s possible that, but I don’t know the
    answer.”
    Following an arbitration hearing, the deputy commissioner determined,
    “The record evidence considered as a whole does not support a finding that
    claimant’s right hip osteoarthritis and his need for a right hip replacement were
    rational consequences of his work activities for ADM.” In the conclusions of law,
    the deputy commissioner wrote:
    As regards to claimant’s claim of a right hip injury, Dr.
    Boulden’s opinion that claimant’s right hip osteoarthritis and need
    for right hip replacement surgery represented a progression of the
    right hip deformities that he had as a result of the valgus deformity
    he developed after his earlier trochanteric fracture and related
    surgery is well reasoned and accepted over the contrary causation
    opinion of Dr. Miller, which is not supported by a rational
    explanation. Claimant has not demonstrated that the right hip
    osteoarthritis that resulted in his having hip replacement surgery
    was a rational consequence of his work duties or that the condition
    was accelerated because of his work duties for ADM.
    Consequently, the deputy denied Warren workers’ compensation benefits.
    Warren appealed to the commissioner.
    The commissioner reversed the deputy’s arbitration ruling, finding:
    The law as to aggravation of preexisting conditions is well-
    settled. While a claimant is not entitled to compensation for the
    results of a preexisting injury or disease, its mere existence at the
    time of a subsequent injury is not a defense. Rose v. John Deere
    Ottumwa Works, 
    76 N.W.2d 756
    (Iowa 1956). If the claimant had a
    preexisting condition or disability that is materially aggravated,
    accelerated, worsened or lighted up so that it results in disability,
    9
    claimant is entitled to recover. Nicks v. Davenport Produce Co.,
    
    115 N.W.2d 812
    (Iowa 1962); Yeager v. Firestone Tire & Rubber
    Co., 
    112 N.W.2d 299
    (Iowa 1961).
    The presiding deputy commissioner’s discussion of
    causation and of pain brought about by work duties does not
    appear to comport with the well-settled law of aggravation of
    preexisting conditions and is discounted as such a standard would
    place a far greater, if not insurmountable burden on an injured
    worker than does the standard set forth in Nicks and Yeager.
    Claimant need not prove any more than the work activities
    materially aggravated, accelerated, worsened, or lighted up the
    progression of his osteoarthritis and resulted in the need for the hip
    replacement surgery.
    The commissioner observed that Warren’s “employment duties were not
    significantly discussed within the arbitration decision.” The commissioner wrote:
    Further, [Warren] explained in great detail the duties of moving
    railcars, cleaning and inspecting the railcars, and ultimately filling
    the cars with product and removing the cars from the facility.
    Between [Warren’s] testimony and the job description it is found
    that [Warren’s] work was heavy, physical labor that required
    walking on uneven ground, standing, crawling, stooping, climbing
    onto and into and out of railcars, climbing steps, bending, twisting,
    lifting, and pulling, amongst other strenuous physical acts.
    [Warren] testified that due to the rough terrain in the rail yard that
    he had fallen several times. [Warren’s] work required him to take
    steps to a control room where he input data into a computer.
    [Warren] worked 12-16 hours per day and had worked up to 80
    hours in a week. [Warren] noted about five to six years prior to the
    arbitration hearing that his work duties had changed and brought
    forth more significant right hip complaints. [Warren] testified that:
    My hip—it got to the point where it was really
    bothering . . . . It got to the point where once I got
    down, it would be hard to get back up. My walking
    going up and down the steps got closer. My hip really
    started to bother me a lot. I was fighting the snow
    clear up to my knees and thighs at times, slipping,
    falling. Just—yeah; it really started to tear me up.
    (Record citations omitted.)
    The commissioner reviewed the records of Drs. Munjal, Boulden, and
    Miller and determined Warren “met his burden to prove that his right hip
    10
    replacement and disability arose out of and in the course of his employment
    duties with [ADM].” Further, the commissioner found Warren had sustained a
    twenty-percent impairment to the whole person. The commissioner concluded
    Warren “sustained a right hip injury through a cumulative process as an
    aggravation of claimant’s preexisting hip condition. That injury manifested itself
    on February 18, 2011[,] when claimant left his employment for medical treatment
    for the hip condition.”
    The commissioner then addressed the issue of the “extent of claimant’s
    loss of earning capacity as a result of his hip replacement.” The commissioner
    considered the many factors of industrial disability and concluded Warren had
    “sustained an injury which permanently disables him from performing work within
    his experience, training, education, and physical capacities,” entitling him an
    award of permanent total disability benefits commencing on February 19, 2011.
    ADM filed a petition for judicial review in the district court. The district
    court found substantial evidence supported the commissioner’s finding of
    causation, despite finding Dr. Munjal’s varying statements in response to the
    attorneys’ letters a “nullity.” The district court wrote:
    However, the Court [] still finds that Dr. Miller’s testimony
    sufficiently supports causation between work and the aggravation
    of the osteoarthritis, which aggravated the condition and
    necessitated surgery. The Court disagrees that Dr. Miller makes
    conflicting assertions. Dr. Miller is simply saying in his first opinion
    that no specific injury at work caused the Warren’s pain in his hip
    but rather the normal physical labor contributed to the acceleration
    of his osteoarthritis. [ADM’s] argument regarding the adjectives
    used to describe the contributing factors is also without merit;
    regardless of the adjectives used to describe the contributions, Dr.
    Miller still found the work activities contributed to the progression
    and acceleration of the osteoarthritis which necessitated surgery.
    Therefore, the Commissioner’s finding that the Warren’s right hip
    11
    osteoarthritis aggravation was proximately caused by the Warren’s
    work activities is supported by substantial evidence. The existence
    of substantial evidence is especially apparent when the
    Commissioner’s credibility determination of Dr. Boulden is
    considered.
    The Court also finds the Commissioner’s credibility
    determination regarding Dr. Boulden is supported by substantial
    evidence. The Commissioner’s determination that Dr. Boulden’s
    opinion was conclusory seems to be based on the fact that he did
    not fully acknowledge the physical nature of the Warren’s
    employment in his June 15, 2011 IME. This is supported by
    substantial evidence as Dr. Miller’s IME on March 13, 2012
    discussed the Warren’s job duties in depth . . . .
    ....
    Last, the Court finds [ADM’s] argument that the osteoarthritis
    is not work related without merit. As stated the Commissioner’s
    finding of causation between work and the aggravation of the
    osteoarthritis was supported by substantial evidence.
    In conclusion, the Court finds that when the record is
    considered as a whole, the Commissioner’s decision is supported
    by substantial evidence even when the evidence supplied by Dr.
    Munjal is not considered. Dr. Miller’s opinion supports a causal link
    between the Warren’s physical work and the aggravation of the
    osteoarthritis and subsequent surgery. [footnote omitted]
    Furthermore, the Commissioner’s finding of lack of creditability in
    Dr. Boulden was supported by substantial evidence. Last, [ADM’s]
    attempt to attribute the osteoarthritis to other causes fails.
    ADM also contended the commissioner had not adequately considered
    Warren’s “planned retirement” in the determination of industrial disability. The
    district court rejected this argument, holding the commissioner’s industrial
    disability decision was not irrational, illogical, or wholly unjustifiable.2
    The district court denied ADM’s subsequent motion to amend its ruling in
    which it argued, “The Commissioner, not the Court, has authority to determine if
    Dr. Miller’s opinion alone proves causation by a preponderance of the evidence.”
    ADM appeals.
    2
    The district court did reverse the commissioner’s assessment of costs of an audiology
    report associated with Warren’s failed claims of hearing loss and tinnitus, and remanded
    to the commissioner for a corrected ruling.
    12
    II. Scope and Standards of Review.
    Iowa Code chapter 17A governs our review of the commissioner’s
    decision.   See Iowa Code § 86.26 (2013); Mike Brooks, Inc. v. House, 
    843 N.W.2d 885
    , 888 (Iowa 2014). The district court acts in an appellate capacity
    when reviewing the commissioner’s decisions to correct errors of law. See Mike
    
    Brooks, 843 N.W.2d at 888
    . “On appeal, we apply the standards of chapter 17A
    to determine whether we reach the same conclusions as the district court. If we
    reach the same conclusions, we affirm; otherwise we may reverse.” 
    Id. at 888-89
    (citation and quotation marks omitted).
    As the trier of fact, it is the commissioner’s duty to weigh the evidence.
    Arndt v. City of Le Claire, 
    728 N.W.2d 389
    , 394-95 (Iowa 2007). We will only
    disturb the commissioner’s finding fact if it is not supported by substantial
    evidence. See Iowa Code § 17A.19(10)(f) (defining substantial evidence as “the
    quantity and quality of evidence that would be deemed sufficient by a neutral,
    detached, and reasonable person, to establish the fact at issue when the
    consequences resulting from the establishment of that fact are understood to be
    serious and of great importance”).
    Evidence is not insubstantial merely because different
    conclusions may be drawn from the evidence. To that end,
    evidence may be substantial even though we may have drawn a
    different conclusion as fact finder. Our task, therefore, is not to
    determine whether the evidence supports a different finding; rather,
    our task is to determine whether substantial evidence, viewing the
    record as a whole, supports the findings actually made.
    Cedar Rapids Cmty. Sch. Dist. V. Pease, 
    807 N.W.2d 839
    , 845 (Iowa 2011)
    (citations omitted).
    13
    III. Discussion.
    A. Medical Causation. As our supreme court has repeatedly emphasized,
    “[o]ur decision is controlled in large part by the deference we afford to decisions
    of administrative agencies.” 
    Pease, 807 N.W.2d at 844
    ; see Mike 
    Brooks, 843 N.W.2d at 889
    .
    Medical causation presents a question of fact that is vested in the
    discretion of the workers’ compensation commission. Mike 
    Brooks, 843 N.W.2d at 889
    ; 
    Pease, 807 N.W.2d at 844
    -45; Dunlavey v. Econ. Fire & Cas. Co., 
    526 N.W.2d 845
    , 853 (Iowa 1995).         “[T]he determination of whether to accept or
    reject an expert opinion is within the ‘peculiar province’ of the commissioner.”
    
    Pease, 807 N.W.2d at 845
    (quoting Deaver v. Armstrong Rubber Co., 
    170 N.W.2d 455
    , 464 (Iowa 1969)).
    ADM argues that because the district court’s analysis excluded Dr.
    Munjal’s contradictory opinions, this case must be remanded to the
    commissioner to reweigh the evidence. ADM relies on McDowell v. Town of
    Clarksville, 
    241 N.W.2d 904
    (Iowa 1976), for this proposition. We reject this
    argument.
    The district court observed,
    The Agency did not make any clear indication that its finding of a
    preponderance of the evidence required both doctors’ opinions.
    There is no explicit evidence that the Agency would have found
    against causation if only Dr. Miller’s opinion was available. The
    parts of the Agency’s decision that [ADM] quotes show that the
    Agency is considering the opinions of the doctors collectively when
    deciding causation, but it does not show that both Drs. Miller’s and
    Munjal’s opinions are necessary to find causation and that Dr.
    Miller’s opinion alone would be insubstantial.
    More importantly, the Court’s job on judicial review is to view
    the record as a whole to see if substantial evidence supports a
    14
    finding of fact. . . . The Court determined that there was substantial
    evidence after it considered the detracting evidence.
    We find no reason to disturb the court’s reasoning.             While ADM
    characterizes the district court’s ruling as a determination the commissioner erred
    in considering Dr. Munjal’s testimony, the clear language used by the district
    court belies that characterization.     The district court recognized that the
    commissioner had weighed the opinions of all three experts on the issue of
    causation, discussing the specifics of each doctor’s statements and the context
    for each opinion. The commissioner reviewed the several doctors’ opinions and
    reasoned:
    [Warren’s] right leg deformity resulted in osteoarthritis and further
    opined that the physical nature of claimant’s employment duties
    materially aggravated and accelerated the osteoarthritis and the
    need for the right hip replacement. The opinions of both Dr. Miller
    and Dr. [Munjal] are supported by reference to the work duties of
    claimant and acknowledge that this is a progression of a preexisting
    condition. The opinion of Dr. Boulden stands alone in the record.
    Dr. Boulden’s report fails to acknowledge the physical nature of
    claimant’s employment in the rail yard, finding it immaterial. Dr.
    Boulden merely writes a conclusory statement that claimant’s work
    duties did not accelerate or cause the osteoarthritis of his hip, for
    which claimant had the hip replacement. Following consideration of
    the medical opinions of the three medical experts it is concluded
    that a preponderance of the evidence supports a conclusion that
    claimant’s right hip osteoarthritis was materially and substantially
    aggravated by claimant’s job duties for defendant, requiring a total
    right hip replacement. Claimant has therefore met his burden to
    prove that his right hip replacement and disability arose out of and
    in the course of his employment duties with defendant. It is further
    concluded that claimant has sustained a 20 percent impairment to
    the whole person along with the restrictions ordered by Dr. Miller.
    (Emphasis added.)
    In an effort to acknowledge ADM’s arguments on judicial review about the
    differing opinions offered by Dr. Munjal, the district court looked at the record
    15
    without Dr. Munjal’s opinions to determine whether there was substantial
    evidence of causation nonetheless. This is not a situation like McDowell, a case
    upon which ADM relied in oral arguments, but had not cited in its briefs.
    McDowell involved an appeal where our supreme court was concerned
    that the commissioner had not considered all the evidence. See 
    McDowell, 241 N.W.2d at 909
    . The McDowell court wrote,
    Obviously an administrative agency cannot in its decision set
    out verbatim all the testimony in a case. Obviously also, if the
    agency quotes some testimony, a losing party should not be able,
    ipso facto, to urge successfully that the agency did not weigh all the
    other evidence. But under the particular record before us we are
    concerned that the commissioner may well have overlooked Dr.
    Caulkins’ answers to the written interrogatories. The commissioner
    set out Dr. Caulkins’ weaker original testimony—and then referred
    to this, if we understand the decision correctly, as Dr. Caulkins’
    strongest testimony. Any reference to Dr. Caulkins’ later, stronger
    answers is conspicuously absent. The record indicates to us that
    the commissioner may well have been unaware of those
    interrogatories and answers. This unawareness may have resulted
    from claimant's filing the interrogatories and answers after the first
    hearing had 
    concluded. 241 N.W.2d at 908
    . The supreme court held, “The proper disposition, however,
    was not for the [district] court to find the facts but rather to return the case to the
    commissioner for decision on the record already made.” 
    Id. at 909.
    The court
    concluded:
    We thus remand the case to the commissioner to weigh and
    consider Dr. Caulkins’ answers to the written interrogatories, if the
    commissioner did not so weigh and consider them originally, and to
    render a supplemental decision. If the commissioner did weigh and
    consider those answers originally, he should so recite in his
    supplemental decision, and his original finding on causation and
    judgment will stand.
    
    Id. 16 Unlike
    McDowell, the commissioner here referenced, quoted, and cited all
    of the opinions of all three doctors, then weighed the opinions, giving little weight
    to Dr. Boulden, recognizing the contradictory opinions of Dr. Munjal, and crediting
    Dr. Miller’s opinions.      Contrary to ADM’s attempt to characterize the district
    court’s ruling otherwise, the district court did not reweigh the evidence here.
    Rather,     it    determined   there   was    substantial   evidence   supporting   the
    commissioner’s conclusion of causation—even without considering Dr. Munjal’s
    opinions.        McDowell does not stand for the proposition that remand to the
    commissioner is the proper action here.
    Our supreme court has repeatedly held that “if plaintiff was diseased and
    his condition was aggravated, accelerated, worsened or ‘lighted up’ by the injury
    so it resulted in the disability found to exist plaintiff was entitled to recover.” Rose
    v. John Deere Ottumwa Works, 
    76 N.W.2d 756
    , 761 (Iowa 1956).                     It has
    approved the standard of “material” aggravation or acceleration. Second Injury
    Fund of Iowa v. Nelson, 
    544 N.W.2d 258
    , 263 (Iowa 1995); Yeager v. Firestone
    Tire & Rubber Co., 
    112 N.W.2d 299
    , 302 (Iowa 1961). This is the standard the
    commissioner applied; we affirm.
    The commissioner found Warren had carried his burden to prove his
    employment with ADM materially aggravated his condition causing the need for
    hip replacement. This ruling is supported by Dr. Miller’s opinion that Warren’s
    “work activity during his ten years at Archer Daniels Midland were significant
    physical activities that contributed to the progression of osteoarthritis resulting in
    17
    the need for a total hip replacement.”3 Dr. Munjal was uncomfortable offering an
    opinion about aggravation of a condition but did sign off on a letter from ADM’s
    attorney agreeing with Dr. Boulden that Warren’s “symptoms may have been
    aggravated by his work.”           The worsening nature of Warren’s condition is
    documented in his medical records, which repeatedly note the strenuous nature
    of Warren’s work activities. As the commissioner stated, “The opinion of Dr.
    Boulden stands alone in the record. Dr. Boulden’s report fails to acknowledge
    the physical nature of claimant’s employment in the rail yard, finding it
    immaterial.”
    It is the commissioner, as fact finder, who is responsible for determining
    the weight to be given expert testimony.            See Sherman v. Pella Corp., 
    576 N.W.2d 312
    , 321 (Iowa 1998). “The commissioner is free to accept or reject an
    expert’s opinion in whole or in part, particularly when relying on a conflicting
    expert opinion.” 
    Pease, 807 N.W.2d at 85
    . In their appellate capacity, courts
    “are not at liberty to accept contradictory opinions of other experts in order to
    reject the finding of the commissioner.” 
    Id. Because the
    commissioner weighed
    the expert opinion evidence thoroughly and documented its finding of causation,
    and the district court accepted the finding of the commissioner as supported by
    substantial evidence in the record, we affirm.
    B. Industrial disability. “Industrial disability is determined by an evaluation
    of the employee’s earning capacity.” 
    Pease, 807 N.W.2d at 85
    2; see also IBP,
    Inc. v. Al-Gharib, 
    604 N.W.2d 621
    , 632 (Iowa 2000). “The commissioner may
    consider a number of factors in determining industrial disability, including
    3
    Dr. Boulden opined that Warren’s “arthritis was the cause of the operation.”
    18
    functional disability, age, education, qualifications, experience, and the claimant’s
    inability, because of the injury, to engage in employment for which he is fitted.”
    
    Pease, 807 N.W.2d at 85
    2 (citation, internal quotation marks, and alterations
    omitted).
    Here, the commissioner determined:
    Claimant is a 63 year old worker who has performed heavy,
    physical labor during his vocational history. Claimant has a limited
    education, having completed only the 9th grade and later obtaining
    his GED. Claimant has obtained training from a community college
    in welding, pipe-fitting, and general construction trades. Claimant is
    not well suited for retraining due to his age and prior educational
    history. Claimant has sustained a significant physical impairment
    from his right hip replacement. He walks with an altered gait and
    may rely upon a cane or other assistance for mobility. Claimant
    cannot return to any of his prior employment positions. The physical
    restrictions set forth by Dr. Miller are severe and would preclude a
    return to any employment within his experience, training, education,
    or physical capacities. Claimant is on social security disability
    benefits. A vocational opinion by Barbara Laughlin, M.A., finds that
    claimant is precluded even from sedentary positions as he can only
    sit for 30 to 60 minutes at a time per Dr. Miller.
    Having considered the various factors of industrial disability
    it is concluded that claimant has sustained an injury which
    permanently disables him from performing work within his
    experience, training, education, and physical capacities. Therefore,
    claimant is entitled to an award of permanent total disability
    benefits.
    ADM argues the commissioner’s determination is erroneous because
    Warren “voluntarily retired.” ADM points out Warren’s testimony in which he
    agreed that as of October 2010 when he visited his personal physician, he had
    planned to retire the following March 2011.
    Because ADM’s challenge to the commissioner’s industrial disability
    determination depends on the application of law to facts, we will not disturb the
    ruling unless it is “irrational, illogical, or wholly unjustifiable.” See Neal v. Annett
    19
    Holdings, Inc., 
    814 N.W.2d 512
    , 526 (Iowa 2012). The commissioner considered
    the relevant factors of functional impairment, age, intelligence, education,
    qualifications, experience, and the ability to engage in the employment for which
    Warren was suited. See id.; see also Larson Mfg. Co., Inc. v. Thorson, 
    763 N.W.2d 842
    , 857 (Iowa 2009) (noting “motivation” as a relevant factor in
    industrial disability inquiry).
    In Second Injury Fund of Iowa v. Nelson, 
    544 N.W.2d 258
    , 265-67 (Iowa
    1995), our supreme court discussed age as a factor in the determination of
    industrial disability.    There, the workers’ compensation commissioner had
    determined the worker’s “proximity to normal retirement age also affects his
    industrial disability. Claimant is near the end of the normal work life. Compared
    to a younger worker with the same injury, claimant has lost less future earning
    capacity as a result of his injury.” 
    Nelson, 544 N.W.2d at 265
    . The supreme
    court rejected this reasoning:
    Industrial disability measures an injured worker’s lost earning
    capacity.       Factors that should be considered include the
    employee’s functional impairment, age, intelligence, education,
    qualifications, experience, and the ability of the employee to
    engage in employment for which he is suited. Thus, the focus is
    not solely on what the worker can and cannot do; the focus is on
    the ability of the worker to be gainfully employed.
    Even more important for purposes of our discussion here is
    the concept that industrial disability rests on a comparison of what
    the injured worker could earn before the injury as compared to what
    the same person could earn after the injury. Thus, the level of post-
    injury earnings is important evidence of whether the injury impaired
    the worker’s capacity to earn. However, the commissioner here did
    not merely consider whether Nelson had the ability to earn the
    same wages after his shoulder injury as he could earn before his
    shoulder injury. The commissioner compared what Nelson could
    earn over his remaining worklife after his injury with what a
    hypothetical worker with the same characteristics, but younger,
    could earn. This comparison is irrelevant in determining Nelson’s
    20
    lost earning capacity. A calculation of the number of years of
    wages lost by Nelson might be helpful in assessing tort damages
    for lost earnings, but that is not the issue in a workers’
    compensation case.
    ....
    When the industrial commissioner concludes, as he did here,
    that an older employee’s industrial disability is less because the
    employee has fewer years left to work, what the commissioner is
    really saying is that the total amount of future lost wages is a factor
    in setting the degree of industrial disability. The incorrectness of
    this analysis is illustrated by applying this concept in another factual
    context. If the total amount of future lost wages affects the amount
    of industrial disability, then highly paid workers would be entitled to
    a greater industrial disability rating than workers in lower-paying
    jobs. This result would occur even though the two workers’
    capacities to be employed at the same level as they were employed
    before the injury are the same. This illustration highlights the fact
    that the comparison made in determining industrial disability is the
    worker’s capacity to earn before and after the injury, not the
    worker’s capacity to earn as compared to other workers.
    We agree with Nelson that the commissioner’s consideration
    of Nelson’s age as a factor reducing his industrial disability because
    Nelson would suffer less total future wage loss than a younger
    worker was erroneous. Our conclusion does not mean that age is
    irrelevant to determining industrial disability. To the extent Nelson’s
    age affects his actual employability, it is appropriately considered.
    As the industrial commissioner recognized in his decision, Nelson’s
    age would limit the retraining options available to him. Additionally,
    one of the vocational rehabilitation experts reported that Nelson
    would “run into the problem of being accepted by [an] employer at
    age sixty” and “at sixty years old you have to have some other skills
    that are pretty marketable if you are going to get on with a new
    employer.” There is simply no evidence in the record that Nelson’s
    age would increase his employability and thereby, reduce the level
    of his industrial disability. Therefore, we hold the commissioner
    committed reversible error in concluding that Nelson had less
    industrial disability than he otherwise would have had merely
    because he was near retirement age.
    
    Id. at 265-67
    (citations omitted).
    We note, too, that ADM’s characterization of Warren’s retirement as
    “voluntary” is not without question. We first observe that Warren testified he
    “wanted to” retire, which is not synonymous with a definite plan to retire.       It
    21
    certainly does not mean, as ADM contends, that Warren had already retired.
    Warren also testified the working conditions “started to tear me up.” The record
    also contains evidence that in May 2011 after his hip replacement, Warren was
    released to return to work with restrictions. He took those restrictions to ADM
    and was informed his restrictions could not be accommodated. Warren testified,
    “I pretty much had to take retirement” and he sought Social Security disability
    “[a]fter I knew that my—my working days was pretty much shot.” On our review
    of the record evidence, we do not find the commissioner’s determination as to
    industrial disability was irrational, illogical, or wholly unjustifiable.
    We affirm the district court’s decision affirming the Iowa Workers’
    Compensation Commissioner’s award of permanent total disability benefits to
    Warren.
    AFFIRMED.