                  IN THE SUPREME COURT OF IOWA
                              No. 27 / 05-1400

                             Filed April 13, 2007

CLIFFORD AYERS,

      Appellant,

vs.

D & N FENCE COMPANY, INC.
and EMC INSURANCE COMPANIES,

      Appellees,

UNITED FIRE AND CASUALTY COMPANY,

      Intervenor-Appellee.


      Appeal from the Iowa District Court for Linn County, Denver D.

Dillard, Judge.



      Employer and employee appeal the judgment of the district court

affirming the decision of the workers’ compensation commissioner.

AFFIRMED.



      David A. O’Brien of Willey, O’Brien, L.C., Cedar Rapids, for

appellant.


      Michael L. Mock of Bradshaw, Fowler, Proctor & Fairgrave, P.C.,

Des Moines, for appellee D & N Fence Company.



      Anne L. Clark of Hopkins & Huebner, P.C., Des Moines, for

appellee EMC Insurance Companies.
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     Chris Scheldrup and Charles A. Blades of Scheldrup Law Firm,

P.C., Cedar Rapids, for appellee United Fire & Casualty Company.
                                    3

STREIT, Justice.

      Be careful what you wish for because it just might come true.

Clifford Ayers injured his right knee in 1987 while working for D & N

Fence Company.         He was paid for an eighteen percent permanent

disability to that lower extremity. In 2002, while still in the employ of D

& N, Ayers injured his knee again.       He filed a petition for workers’

compensation alleging the 2002 injury caused additional disability to his

right leg and resulted in a knee replacement surgery. D & N denied the

allegations claiming Ayers’s current disability was the result of his 1987

injury and had little or nothing to do with the 2002 injury.           The

commissioner agreed with D & N and awarded Ayers medical benefits.

D & N cried foul claiming the commissioner should not have imposed

liability upon D & N for additional medical expenses based on the 1987

injury when Ayers’s petition alleged those expenses were necessitated by

the 2002 injury.
      We conclude the commissioner did not abuse his discretion when

he imposed liability for the 1987 injury. D & N was well aware of the

earlier injury and even made it the focus of the hearing. Moreover, we

find D & N’s insurer in 1987 did not have a constitutional right to notice

regarding the possible imposition of liability based upon the 1987 injury.

Any obligation to notify the insurer was that of D & N. Accordingly, we

affirm the district court.

      I.     Facts and Prior Proceedings

      Ayers was fifty-six years old at the time of the hearing. He had

been working for his brother’s company, D & N, for twenty-six years. He

began his career as a fence installer and was promoted to foreman, yard
                                   4

foreman, and finally manager of commercial sales, a position he has held

since 1989.

      Ayers’s claim in this case involves an injury to his right knee.

Ayers first injured his knee in 1987. He was carrying some materials

through a doorway at work when he fell. This injury ultimately required

arthroscopic surgery resulting in the removal of a significant amount of

cartilage.    Ayers was found to have sustained an eighteen percent

impairment to his right leg, and accordingly was paid permanent partial

disability benefits. In 2002, Ayers injured his right knee at a D & N job

site when he stepped in a hole. He twisted his knee and felt significant

pain. Ayers immediately left the job site and reported the injury to D &

N. A few days later, Ayers saw his family doctor who referred him to Dr.

Fabiano, an orthopedic surgeon.
      Dr. Fabiano concluded Ayers suffered from a medial collateral

ligament (MCL) strain.     X-rays showed degenerative arthritis.     Dr.

Fabiano opined the MCL strain may have “aggravate[d] and startle[d]”

Ayers’s degenerative arthritis. He performed knee replacement surgery

after more conservative treatments did not alleviate Ayers’s pain.   The

surgery was a success and Ayers returned to work after seven weeks of

recovery.

      In April 2003, Ayers filed a workers’ compensation claim for his

March 2002 injury.       Ayers sought reimbursement for his medical

expenses ($51,174.62), seven weeks of healing period benefits at $599.97

per week, and 110 weeks of permanent partial disability benefits at the

same rate. D & N and its insurer, EMC, disputed whether Ayers’s 2002

injury caused any new permanent disability and the knee replacement

surgery.
                                     5

       A deputy workers’ compensation commissioner conducted a

hearing concerning Ayers’s claim.        Ayers pursued two theories of

recovery.     First, he argued the March 2002 injury aggravated or

accelerated a preexisting condition (degenerative arthritis) and caused

both the knee replacement surgery and additional disability to his right

leg. Alternatively, Ayers argued the knee replacement surgery and the

additional disability were proximately caused by the cumulative effect of

the 1988 surgery and fifteen years of walking over uneven terrain while

working for D & N.
       At the beginning of the hearing, the attorney for D & N and EMC

stated:

       I believe there will be testimony . . . in this case that Mr.
       Ayers’ problems with his right knee were ongoing from 1987
       to 1988, and that essentially what we’re looking at here is
       not a new injury, but it’s simply a continuation of the ’87,
       ’88 injury. And it’s our position, Your Honor, that all of this
       is really an ongoing part of the ’87, ’88 injury. And if you
       look at—It’s really more analogous to Smithart [654 N.W.2d
       891 (Iowa 2002)], where everything should be looked at as
       part of the first injury as opposed to any ongoing injury that
       we have.

       The deputy commissioner ruled in favor of D & N finding Ayers

“clearly had serious degenerative joint disease prior to March 25, 2002”

and that he “failed to prove that the proximate cause of his need for the

knee arthroplasty surgery was the work injury.”

       Ayers appealed the deputy’s decision to the commissioner arguing

inter alia:

       Even if the court concludes that Ayers’ knee replacement
       surgery was not caused by trauma or cumulative trauma,
       the medical expenses related to the knee replacement
       surgery should still be paid . . . [because] the 1987 work
       related injury was a cause of Ayers’ degenerative arthritis
       condition.
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      In his appeal decision, the commissioner succinctly ruled:

      Claimant alleged and the parties stipulated that the claimant
      sustained a traumatic injury on March 25, 2002, when he
      stepped in a hole. In 1988 claimant had surgery and
      cartilage was removed from his right knee as a result of a
      1987 work-related injury with this same employer for which
      weekly compensation was paid. All the physicians in this
      case attribute the knee replacement surgery to the 1988
      surgery for the 1987 injury. None clearly attribute the
      surgery to the 2002 injury. Claimant proved convincingly
      that the surgery was causally related to the 1987 injury but
      failed to carry the burden of proving that the 2002 injury
      was a substantial factor in the need for the surgery.
      Accordingly, claimant is entitled to recover the requested
      [medical] benefits under section 85.26(2) for the 1987 injury
      . . . but he is not entitled to recover weekly compensation for
      the 2002 injury.

      The motion to reconsider filed by D & N and EMC alerted the

commissioner to the fact United Fire & Casualty Company insured D & N

at the time of the 1987 injury. D & N and EMC noted Ayers’s petition did

not allege entitlement to medical benefits arising from the 1987 injury,

and urged any liability for such medical benefits should be relitigated by

the proper parties.       Ayers also requested a rehearing arguing the

commissioner failed to address the issue of cumulative trauma.

      In his decision on rehearing, the commissioner modified the

decision by relieving EMC from liability and affirmed the remainder of his

decision.

      Ayers filed a petition for judicial review in Linn County. D & N filed

a cross-petition for judicial review and United Fire filed a petition to

intervene. After United Fire was allowed to intervene, it filed a motion to

present     additional   evidence   concerning   insurance   coverage   and

causation of Ayers’s current disability and knee replacement surgery.

The district court denied United Fire’s motion and dismissed all issues

pertaining to insurance coverage without prejudice.
                                       7

       Thereafter, the district court upheld the commissioner’s ruling. It

found the commissioner’s findings of facts were supported by substantial

evidence. The court rejected D & N’s argument that the commissioner

erred in ordering payment of medical benefits resulting from the 1987

injury when Ayers’s petition alleged a 2002 injury date. The court also

rejected United Fire’s claim it had a right to notice and an opportunity to

defend against the imposition of liability based upon the 1987 injury.

The court agreed with the commissioner that any obligation to notify

United Fire was D & N’s obligation pursuant to Iowa Code section 87.10

(2001). The court stated Ayers

       is entitled to compensation and any dispute between his
       employer and the employer’s insurance companies should
       not be a basis for delaying his rights.     There was no
       “surprise development” which prejudiced D & N Fence . . . .

       Ayers filed a notice of appeal. D & N and United Fire filed a notice

of cross appeal. Ayers contends the commissioner erred in finding the

2002    injury   did   not   cause   permanent   disability   and   the   knee

replacement surgery. He argues the commissioner erred by applying the

wrong standards to determine whether the 2002 injury aggravated a

preexisting condition or was a cumulative injury.        He also claims the

commissioner erred by admitting into evidence a second report by D &

N’s expert because it was created and produced after the case

preparation completion date established in the agency’s hearing

assignment order. D & N and United Fire both argue the commissioner

erred by awarding Ayers medical benefits for the 1987 injury because the

issue was not properly presented to the commissioner for consideration.
                                        8

      II.     Scope of Review

      “ ‘We review the district court decision by applying the standards of

the [Iowa] Administrative Procedure Act to the agency action to determine

if our conclusions are the same reached by the district court.’ ” Univ. of

Iowa Hosp. & Clinics v. Waters, 674 N.W.2d 92, 95 (Iowa 2004) (quoting

Locate.Plus.Com, Inc. v. Iowa Dep’t of Transp., 650 N.W.2d 609, 612 (Iowa

2002)).      The Iowa Administrative Procedure Act provides fourteen

grounds upon which a reviewing court may reverse the decision of the

workers’ compensation commissioner.           Iowa Code § 17A.19(10).            The

relevant     grounds   for   this   appeal   are   (1)   the   agency   action    is

unconstitutional, (2) the agency action is not supported by substantial

evidence, and (3) the agency action is an abuse of discretion.                   Id.

§ 17A.19(10)(a), (f), and (n). “The burden of demonstrating the required

prejudice and the invalidity of agency action is on the party asserting

invalidity.” Id. § 17A.19(8)(a).
      III.    Merits

      A.      Whether     Substantial    Evidence     Supports    the
              Commissioner’s Finding that Ayers’s Knee Replacement
              Surgery was not Causally Related to the 2002 Injury
      The commissioner found Ayers failed to prove the 2002 injury was

a proximate cause of his disability and the knee replacement surgery.

The commissioner also found Ayers’s current disability was not the result

of cumulative trauma because “[t]he record does not show that claimant

could have avoided the knee replacement surgery if he had not worked

for the employer after 1988.”

      Substantial evidence supports the commissioner’s findings.                 See

Waters, 674 N.W.2d at 95 (noting we may reverse the commissioner’s

findings only if they are not supported by substantial evidence in the
                                    9

record); Iowa Code § 17A.19(10)(f)(1) (stating a decision of the

commissioner is supported by substantial evidence if the evidence is of

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”).      Three physicians

rendered opinions on the cause of Ayers’s disability and knee

replacement surgery:     Dr. Fabiano, Dr. Riggins, and Dr. Stenberg.

Causal connection is essentially within the domain of expert testimony.

Bradshaw v. Iowa Methodist Hosp., 251 Iowa 375, 383, 101 N.W.2d 167,

171 (1960).    Dr. Fabiano was Ayers’s treating physician and has a

specialty in orthopedics. In the days following Ayers’s 2002 injury, Dr.

Fabiano diagnosed Ayers as having preexisting degenerative joint disease

with an MCL strain.      Dr. Fabiano noted x-rays showed significant

degeneration with “near bone on bone” changes in the knee.             On

September 9, 2002, Dr. Fabiano performed Ayers’s knee replacement

surgery and his postoperative diagnosis was end-stage degenerative joint

disease.   Dr. Fabiano concluded the cause of the knee replacement

surgery was Ayers’s degenerative arthritis, not the 2002 injury.       Dr.

Riggins reviewed Ayers’s medical records and agreed with Dr. Fabiano’s

conclusions.

      Dr. Stenberg conducted an independent medical evaluation. His

report opined “[t]he most likely cause of Mr. Ayers’ degenerative arthritis

condition would be his morbid obesity.” Although Dr. Stenberg did later

provide the only testimony supporting the claim that Ayers’s disability

and knee replacement surgery were causally related to the 2002 injury,
                                    10

he did so only after Ayers’s counsel inquired whether that injury

exacerbated Ayers’s preexisting degenerative arthritis.

      The commissioner found Ayers had serious degenerative joint

disease that had been symptomatic prior to March 25, 2002. Although

Ayers sustained an injury on March 25, 2002, the commissioner found

he failed to prove the injury materially aggravated his preexisting

condition. Likewise, the commissioner rejected Ayers’s cumulative injury

argument. He found “[t]he record does not show that [Ayers] could have

avoided the knee replacement if he had not worked for the employer after

1988. The cumulative trauma exposure was incidental in this case and

did not materially change the outcome.”
      There is substantial evidence in the record to support the

commissioner’s factual findings. Moreover, the commissioner applied the

correct legal standards in making these determinations.       Ayers finds

fault with the commissioner’s statement that Ayers failed to prove “the

2002 injury significantly changed the course of the preexisting injury to

bring about the need for knee replacement surgery.” Ayers claims the

commissioner applied “a higher, hyper-technical, and incorrect standard”

in determining whether the 2002 injury materially aggravated his

preexisting condition. Ayers is grasping at straws. A claimant has the

burden of proving his work-related injury was a proximate cause of his

disability.   Meyer v. IBP, Inc., 710 N.W.2d 213, 220 n.2 (Iowa 2006)

(quoting Freeman v. Luppes Transp. Co., 227 N.W.2d 143, 148 (Iowa

1975)). In order for a cause to be proximate, it must be a “substantial

factor.” Kelly v. Sinclair Oil Corp., 476 N.W.2d 341, 349 (Iowa 1991). The

commissioner applied the correct standard and we have no quarrel with

his analysis.
                                     11

      Likewise, we find the commissioner applied the correct standard in

determining    whether    Ayers   suffered   a   cumulative   injury.   The

commissioner found Ayers failed to prove he “could have avoided the

knee replacement if he had not worked for the employer after [his first

knee surgery].” In order to be compensable, the cumulative trauma must

be work related.     Ayers offered no medical evidence supporting his

contention that his disability was caused by work-related repetitive

trauma.

      B.      Whether     Substantial     Evidence    Supports the
              Commissioner’s Finding that Ayers’s Knee Replacement
              Surgery was the Result of the 1987 Injury
      Substantial evidence supports the commissioner’s finding that

Ayers “proved convincingly” his disability and knee replacement surgery

were causally related to his 1987 work-related injury. Dr. Riggins opined

Ayers’s degenerative arthritis was the expected result of the 1988

arthroscopic surgery, which was required after Ayers’s 1987 injury. Dr.

Stenberg agreed Ayers’s earlier surgery “played a factor” in his

degenerative arthritis.    Dr. Bickel, who performed the arthroscopic

surgery after the 1987 injury, predicted Ayers would continue to have

problems with his right knee and eventually require knee replacement

surgery.

      Having found substantial evidence to support the commissioner’s

ruling, we turn now to the consequences of his findings.

      C.      Whether the Commissioner Abused his Discretion in
              Considering the 1987 Injury as a Cause When Ayers Pled
              2002 as the Date of Injury
      D & N argues the commissioner erred in awarding Ayers benefits

for his 1987 injury because the issue was not properly presented to the

commissioner for consideration.           Whether Ayers’s application for
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workers’ compensation benefits sufficiently informed his employer of the

possibility of an award for the 1987 injury is a matter within the agency’s

discretion.   Waters, 674 N.W.2d at 96.     Thus, the proper standard of

review is an abuse of discretion. Id.

      Ayers’s application for benefits alleged an injury date of “[o]n or

about March 25, 2002.” D & N argues Ayers should have been required

to file a new application for benefits alleging 1987 as the date of the

injury. In Waters, we reiterated “[a]n application for arbitration is not a

formal pleading and is not to be judged by the technical rules of

pleading.” Id. at 96–97 (quoting Coghlan v. Quinn Wire & Iron Works, 164

N.W.2d 848, 850 (Iowa 1969)).       Instead, “[t]he key to pleading in an

administrative process is nothing more than opportunity to prepare and

defend. The employer is to be afforded a substantive right to be at least

generally informed as to the basic material facts upon which the

employee relies as a basis for compensation.” Id. at 97 (quoting James R.

Lawyer and Judith Ann Graves Higgs, Iowa Workers’ Compensation—

Law & Practice § 21-7, at 231 (3d ed. 1999)).
      The commissioner did not abuse his discretion in considering the

1987 injury as the cause of Ayers’s disability and knee replacement

surgery because D & N was well aware of Ayers’s long-standing history of

knee problems. In fact, D & N made the 1987 injury and subsequent

surgery in 1988 an integral part of the hearing. Its attorney stated “what

we’re looking at here is not a new injury, but it’s simply a continuation of

the ’87, ’88 injury. And it’s our position Your Honor, that all of this is

really an ongoing part of the ’87, ’88 injury.” D & N generated expert

opinion testimony from Dr. Riggins to support this claim. Dr. Riggins

was asked by defense counsel to review the Ayers file and opined “the
                                          13

osteoarthritis present in [Ayers’s] right knee was the expected result of

the earlier [1988] surgical procedure.”                Defense counsel was so

persuasive the commissioner adopted her argument. What D & N wished

for came true. This is not a “surprise development” that prejudiced the

employer. Eberhart Constr. v. Curtin, 674 N.W.2d 123, 125 (Iowa 2004).

The commissioner correctly pointed out “[n]othing would be gained by

requiring another proceeding explicitly based on the 1987 injury.” While

D & N may have been surprised by the consequences of its argument,

this is not Ayers’s problem. Even if we were to order a new hearing, D &

N would be barred from arguing the 1987 injury did not cause Ayers’s

disability and knee replacement surgery because it already proved this

very matter. See generally Winnebago Indus., Inc. v. Haverly, 727 N.W.2d

567, 573–75 (Iowa 2006) (discussing doctrine of judicial estoppel).
       In 1988, Ayers was paid for an eighteen percent permanent partial

disability to his lower right leg. Since he proved the knee replacement

surgery performed in 2002 was necessary to treat the 1987 injury, Ayers

is entitled to be reimbursed for the reasonable cost of that treatment.

Iowa Code § 85.26(2). He is not entitled to any additional temporary or

permanent disability payments because more than three years have

passed since he received his last disability payments for the 1987

injury. 1 Id. § 85.26(1).


       1On   appeal, Ayers argues the commissioner erred by admitting into evidence a
second report by Dr. Riggins which was produced after the deadline for discovery.
Ayers complained the late-produced report was prejudicial because it “for the first time
offers expert testimony with regard to the issue of apportionment” of disability between
the 1987 injury and the 2002 injury. According to the report, Ayers’s current 50%
impairment of his lower right extremity should be reduced by 18%, which was the
amount of his impairment prior to March 25, 2002. In other words, D & N used this
report to argue any award of disability payments should be based on 32% impairment
rather than 50%. Because we affirm the commissioner’s determination Ayers is not
entitled to additional compensation for disability, this issue is moot.
                                     14
      D.    Whether       United   Fire’s     Due   Process      Rights   were
            Violated
      Finally,   United   Fire   argues     the   commissioner    violated   its

constitutional right to due process when it considered the 1987 injury.

We review constitutional claims de novo.             Consumer Advocate v.

Commerce Comm'n, 465 N.W.2d 280, 281 (Iowa 1991).

      United Fire did not participate in the hearing. It claims it had a

right to notice and an opportunity to defend against Ayers’s claim for

additional workers’ compensation benefits for the 1987 injury. See Carr

v. Iowa Employment Sec. Comm’n, 256 N.W.2d 211, 214 (Iowa 1977)

(stating the essential elements of due process are notice and an

opportunity to defend). However, the insurer does not have a statutory

or constitutional right to notice from the employee. The employee is only

required to notify the employer of his claim. Iowa Code §§ 85.23, .24.

The commissioner correctly stated any obligation to notify United Fire

was that of D & N’s. See id. § 87.10. The district court aptly held:

      Whether United Fire & Casualty Company must pay the
      medical expenses is not an issue which should be a concern
      for [Ayers]. He is entitled to compensation and any dispute
      between his employer and the employer’s insurance
      companies should not be a basis for delaying his rights.

We agree. The commissioner did not violate United Fire’s due process

rights.

      IV.   Conclusion

      Substantial evidence supports the commissioner’s findings that

Ayers’s disability and knee replacement surgery were caused by the 1987

injury and not the 2002 injury.       Consequently, Ayers is entitled to

reimbursement for his medical expenses.           The commissioner did not

abuse his discretion in considering the 1987 injury when Ayers pled

2002 as the date of injury because D & N raised the 1987 injury as the
                                    15

cause of Ayers’s disability and knee replacement surgery.   Finally, the

commissioner did not violate United Fire’s due process rights because

any obligation to notify United Fire was that of D & N.

      AFFIRMED.
