Citation Nr: 21011030 Decision Date: 02/26/21 Archive Date: 02/26/21 DOCKET NO. 14-10 109 DATE: February 26, 2021 ORDER Entitlement to service connection for right ear hearing loss is granted. Entitlement to service connection for bilateral knee disability, to include as secondary to service-connected disabilities, is denied. FINDINGS OF FACT 1. The evidence is at least evenly balanced as to whether the Veteran’s right ear hearing loss began during active service. 2. The Veteran’s bilateral knee disability did not have its onset in service, did not manifest to a compensable degree within the first post-service year, was not otherwise related to an in-service injury or disease, and was not caused or aggravated by service-connected disability. CONCLUSIONS OF LAW 1. With reasonable doubt resolved in favor of the appellant, the criteria for service connection for right ear hearing loss are met. 38 U.S.C. §§ 1131, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.385. 2. The criteria for service connection for bilateral knee disability, to include as secondary to service-connected disabilities, are not met. 38 U.S.C. §§ 1101 (3), 1110, 1111, 1112, 1113, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.307, 3.309, 3.310. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty from January 1979 to March 1982. The appellant is his surviving spouse. The Veteran died and, in April 2020, the appellant requested to be substituted for the Veteran (see April 2020 “Request for Substitution of Claimant Upon Death of Claimant” form (VA Form 21P-0847)). Later in April 2020, the appellant was substituted for the Veteran with respect to the issues of entitlement to service connection for right ear hearing loss and bilateral knee disability (see an April 2020 letter from the agency of original jurisdiction (AOJ)). These matters initially came before the Board of Veterans Appeals (Board) from September 2011 and March 2013 rating decisions. The Veteran testified before the undersigned Veterans Law Judge (VLJ) at a February 2018 hearing and a transcript of the hearing has been associated with his claims file. In April 2018 and December 2019, the Board remanded these matters for further development. Specifically, the Board instructed the AOJ to, among other things, ask the Veteran to identify any outstanding treatment records and to complete the appropriate authorization form to allow VA to obtain any outstanding private medical records, obtain all outstanding VA treatment records, obtain the Veteran’s relevant Social Security Administration (SSA) records, and obtain medical opinions as to whether the Veteran’s claimed bilateral knee disability was related to service or was caused or aggravated by service-connected disabilities. Pursuant to the Board’s remand, the Veteran and the appellant were asked to identify any outstanding treatment records and to complete the appropriate authorization form to allow VA to obtain any outstanding private medical records by way of letters dated in December 2019, March 2020, and June 2020. Copies of the authorization forms (VA Forms 21-4142a and 21-4142) were included with the letters. Moreover, all identified outstanding VA treatment records and private medical records were obtained and associated with the claims file, all relevant outstanding SSA records were obtained and associated with the claims file, and medical opinions were most recently provided in August and October 2020 as to whether the Veteran’s claimed bilateral knee disability was related to service or was caused or aggravated by service-connected disabilities. As explained in more detail below, the Board finds the August and October 2020 opinions to be adequate and of substantial probative value. Therefore, the AOJ substantially complied with the Board’s pertinent remand instructions. See Dyment v. West, 13 Vet. App. 141, 146- 47 (1999); Stegall v. West, 11 Vet. App. 268 (1998). Service Connection Service connection will be granted if the evidence demonstrates that current disability resulted from an injury suffered or disease contracted in active military, naval, or air service. 38 U.S.C. § 1131; 38 C.F.R. § 3.303(a). Establishing service connection generally requires competent evidence of three things: (1) current disability; (2) in-service injury or disease; and (3) a relationship between the two. Saunders v. Wilkie, 886 F.3d 1356, 1361 (Fed. Cir. 2018). Consistent with this framework, service connection is warranted for a disease first diagnosed after service when all the evidence, including that pertinent to service, establishes that the disease was incurred in service. 38 C.F.R. § 3.303(d). Pursuant to 38 C.F.R. § 3.303(b), where a chronic disease is shown as such in service, subsequent manifestations of the same chronic disease are generally service connected; if a chronic disease is noted in service but chronicity in service is not adequately supported, a showing of continuity of symptomatology after separation is required. Entitlement to service connection based on chronicity or continuity of symptomatology pursuant to 38 C.F.R. § 3.303(b) applies only when the disability for which the Veteran is claiming compensation is due to a disease enumerated on the list of chronic diseases in 38 U.S.C. § 1101(3) or 38 C.F.R. § 3.309(a) (e.g., organic diseases of the nervous system (such as sensorineural hearing loss) and arthritis). Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). In addition, such chronic diseases are presumed to have been incurred in service if they manifested to a compensable degree within one year of separation from service. 38 U.S.C. §§ 1101(3), 1112(a)(1), 1113; 38 C.F.R. §§ 3.307(a), 3.309(a). Although entitlement to service connection on any of the presumptive bases noted above may not be established, a claimant is not precluded from establishing service connection on a direct basis. See 38 U.S.C. § 1113 (b); 38 C.F.R. § 3.303 (d) (the availability of service connection on a presumptive basis does not preclude consideration of service connection on a direct basis). Service connection is also provided for disability which is proximately due to, the result of, or aggravated by service-connected disease or injury. Allen v. Brown, 7 Vet. App. 439 (1995); 38 C.F.R. § 3.310. 1. Entitlement to service connection for right ear hearing loss Hearing loss is considered to be a disability for VA purposes when the auditory threshold in any of the frequencies 500, 1000, 2000, 3000, or 4000 Hertz is 40 decibels or greater; or when the auditory thresholds for at least three of these frequencies are 26 decibels or greater; or when speech recognition thresholds using the Maryland CNC Test are less than 94 percent. 38 C.F.R. § 3.385. The Veteran contended that he had current right ear hearing loss which had its onset in service. The Board finds, for the following reasons, that the Veteran experienced current right ear hearing loss disability at the time of his death, and that the evidence is at least evenly balanced as to whether this disability began during active service. The report of a VA audiological evaluation dated in April 2018 shows the Veteran experienced right ear hearing loss as defined by VA at the time of his death. See 38 C.F.R. § 3.385. There is also evidence of right ear hearing impairment in service and evidence of continuous hearing loss symptoms in the years following service. In this regard, the Veteran reported that he began to experience hearing impairment in service and his post-service medical records and lay statements essentially indicate that he experienced continuous hearing loss symptoms and/or been informed by his family members of his impaired hearing in the years following service (see the report of the March 2019 VA audiological examination and the Veteran’s testimony during the February 2018 Board hearing). The Veteran was competent to report continuous hearing loss symptoms in the years following service and others are competent to report their observations of the Veteran’s symptoms. See Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007); see also Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006). There is nothing to explicitly contradict these lay reports and they are generally consistent with the evidence of record. Thus, the Board finds that the reports of continuous hearing loss symptoms in the years following service are credible. The audiologist who conducted a January 2013 VA audiological examination opined that the Veteran’s hearing loss was not likely (“less likely than not) a result of in-service noise exposure. The examiner reasoned that the Veteran’s hearing loss was within normal limits during his December 1978 entrance examination, that there was mild hearing loss at 3,000 Hertz in the left ear during his February 1982 separation examination, and that there was no significant shift in hearing when comparing the entrance and separation examinations. The Institute of Medicine (IOM) concluded that based on current knowledge of cochlear physiology, there is no sufficient scientific basis for the existence of delayed onset hearing loss. The IOM did not rule out that delayed onset might exist, but because the requisite longitudinal animal and human studies have not been done, and based on current knowledge of acoustic trauma and the instantaneous or rapid development of noise induced hearing loss, there was no reasonable basis for delayed onset hearing loss. The audiologist who conducted a March 2019 VA audiological examination opined that the Veteran’s right ear hearing loss was not likely (not “at least as likely as not”/”50 percent probability or greater”) caused by or a result of an event in service. The examiner reasoned that the Veteran reported that his hearing loss had its onset in approximately 1981 and was the result of missiles that were fired from his ship in service. However, there was no significant permanent shift in hearing thresholds beyond test variability during the time from his entrance examination to his separation examination. This was objective evidence that there was no permanent auditory damage during active duty from noise exposure. There were no reports of complaints or treatment for decreased hearing in his service treatment records or at the time of his separation from service. Although noise exposure in service was conceded and the relationship of noise exposure, auditory damage, and hearing loss is well established, auditory damage and hearing loss are not conceded based on noise exposure alone. Rather, there must be a nexus of auditory damage to related current hearing loss to military noise exposure, as opposed to another etiology. As the evidence was against such a nexus in this case, it was not likely (“less likely than not”) that the Veteran’s hearing loss was related to military noise exposure. Also, the examiner noted that he was unable to opine as to the Veteran’s hearing status one year following service because there were no hearing examinations to review from that time period. The January 2013 and March 2019 opinions are all of little, if any, probative value because they are partially based on the absence of clinical evidence of treatment for hearing loss problems in service, and they do not take into account the competent and credible lay reports of continuous hearing loss symptoms in the years following service. In this regard, a medical opinion is inadequate if it is based solely on the absence of documentation in the record and does not take into account the Veteran’s reports of symptoms and history (even if recorded in the course of the examination). Dalton v. Peake, 21 Vet. App. 23 (2007). Also, the Board points out that the absence of hearing loss disability (as defined by 38 C.F.R. § 3.385) in service is not in and of itself fatal to a claim of service connection for hearing loss disability. See Hensley v. Brown, 5 Vet. App. 155, 159 (1993); Ledford v. Derwinski, 3 Vet. App. 87, 89 (1992). In other words, the absence of evidence of a hearing loss disability as defined by this regulation in service does not necessarily mean that the Veteran did not experience any hearing impairment in service. In sum, the evidence reflects that the Veteran experienced right ear hearing impairment in service and that there were continuous hearing loss symptoms in the years following service. He also experienced current right ear hearing loss as defined by VA at the time of his death. There is no adequate medical opinion contrary to a conclusion that the current right ear hearing loss had its onset in service. Thus, the evidence is at least evenly balanced as to whether this disability had its onset in service. As the reasonable doubt created by this relative equipoise in the evidence must be resolved in favor of the appellant, entitlement to service connection for right ear hearing loss is warranted. 38 U.S.C. § 5107 (b); 38 C.F.R. § 3.102. See also Buchanan, 451 F.3d at 1335 (“[N]othing in the regulatory or statutory provisions [relating to evidence to be considered] require both medical and competent lay evidence; rather, they make clear that competent lay evidence can be sufficient in and of itself”). 2. Entitlement to service connection for bilateral knee disability, to include as secondary to service-connected disabilities The Veteran contended that he had bilateral knee disability that was related to knee problems that he experienced in service. In the alternative, he contended that his knee disability was caused or aggravated by his service-connected back disability and/or its associated lower extremity neurological disability (to include to the extent that these disabilities resulted in obesity which, in turn, resulted in his knee disabilities). The Board points out that although obesity is not a disability for VA compensation purposes, obesity may act as an “intermediate step” between a service-connected disability and a current disability that may be service-connected on a secondary basis under 38 C.F.R. § 3.310 (a). VAOPGCPREC 1-2017. See also Marcelino v. Shulkin, 29 Vet. App. 155 (2018) (affirming the Board’s decision that service connection is not warranted for obesity as it is not in and of itself a disability for VA purposes, but not addressing VAOPGCPREC 1-2017). In order to establish service connection on this basis, three criteria must be met: (1) the service-connected disability must have caused the veteran to become obese; (2) the obesity as a result of the service connected disability must be a substantial factor in causing the disability for which service connection is sought; and (3) the disability for which service connection is sought would not have occurred but for obesity caused by the service-connected disability. Id. The question for the Board is whether the Veteran had current disability that began during service or was at least as likely as not related to an in-service injury, event, or disease or was caused or aggravated by service-connected disability. The Board finds, for the following reasons, that, while there is evidence that the Veteran had current bilateral knee disability at the time of his death, the claimed knee disability is not shown to have had its onset in service, to have been otherwise related to a disease or injury in service, or to have been caused or aggravated by service-connected disability. As an initial matter, the Board notes that there is evidence of a left knee injury that pre-existed service. For instance, the Veteran reported on a December 1978 report of medical history form completed for purposes of entrance into service that he fractured his left knee while playing football prior to service. Regardless, a veteran will be considered to have been in sound condition when examined, accepted and enrolled for service, except as to defects, infirmities, or disorders noted at entrance into service, or where clear and unmistakable (obvious or manifest) evidence demonstrates that an injury or disease existed prior thereto and was not aggravated. 38 U.S.C. § 1111; 38 C.F.R. § 3.304 (b). The term “noted,” in 38 U.S.C. § 1111, refers to “[o]nly such conditions as are recorded in examination reports.” 38 C.F.R. § 3.304 (b). A “[h]istory of preservice existence of conditions recorded at the time of examination does not constitute a notation of such conditions.” 38 C.F.R. § 3.304 (b)(1). Although the Veteran was competent to report a history of left knee problems prior to service, there is no other evidence of any pre-existing left knee disability prior to service and the Veteran’s December 1978 entrance examination was normal. Therefore, the Board finds that the evidence is not clear and unmistakable that any left knee disability pre-existed service and was not aggravated in service and the Veteran is presumed sound at service entrance. 38 U.S.C. § 1111. Medical records, including the report of a March 2019 VA knee examination, show the Veteran experienced bilateral degenerative arthritis of the knees and bilateral status post total knee arthroplasty at the time of his death. Therefore, current bilateral knee disability is demonstrated. The Veteran contended that he began to experience knee problems in service and that he experienced continuous bilateral knee symptoms in the years following service. The Veteran was competent to report the history of his claimed bilateral knee disability (including a continuity of symptomatology in the years following service). However, his reports must be weighed against the other evidence of record and their credibility must be assessed. See Jandreau, 492 F.3d at 1377; Buchanan, 451 F.3d at 1337. Service treatment records reflect that in April 1979, the Veteran was treated for knee abrasions after he fell on the ground. In September 1979, he was treated for right knee abrasions and a sprain. Also, he reported on a February 1982 report of medical history form completed for purposes of separation from service that he was occasionally bothered by his knee. There is no evidence of any other complaints of or treatment for knee problems in the Veteran’s service treatment records and his March 1982 separation examination was normal other than for hernia, pes planus, and defective hearing. Also, the earliest clinical evidence of knee problems following service is an October 2004 progress note from New York Medical College, which reveals that the Veteran was experiencing bilateral knee pain. The Board acknowledges that there is lay evidence of earlier knee problems in that the Veteran reported a continuity of knee symptomatology in the years following service. As explained below, however, the Board finds that the Veteran’s reports as to the history of his claimed bilateral knee disability (to include his reports of a continuity of symptomatology in the years following service) are not credible. The absence of any clinical evidence of knee problems for over two decades after the Veteran’s separation from active service in March 1982, along with the inconsistent statements noted below, is one factor weighing against a finding that his current bilateral knee disability was present in service or in the year or years immediately after service. See Maxson v. West, 12 Vet. App. 453, 459 (1999), aff’d sub nom. Maxson v. Gober, 230 F.3d 1330, 1333 (Fed. Cir. 2000); see also Forshey v. Principi, 284 F.3d 1335, 1358 (Fed. Cir. 2002) (en banc) (the Board may consider in its assessment of a service connection claim the passage of a lengthy period of time wherein the veteran has not complained of the malady at issue).” Moreover, the Veteran provided information and statements which are inconsistent with his reports of a continuity of bilateral knee symptomatology in the years following service. As explained above, he reported that his bilateral knee disability had its onset in service and that he experienced continuous knee symptoms in the years following service. However, he reported during a March 2011 VA examination that he experienced “knee pains since around 1986” and that he did not “recall serous traumatic injury to either knee.” Also, he reported during a March 2019 VA knee examination that he did not have “knowledge of any direct or indirect injury to the right knee,” that he underwent a total left knee replacement in 2009, and that “he developed right knee problems following [the] left total knee replacement.” In light of the fact that the Veteran’s March 1982 separation examination did not reflect any knee abnormalities, the absence of any clinical evidence of knee problems for over two decades following his separation from service in March 1982, and the information and statements provided by the Veteran that are inconsistent with his reports of a continuity of knee symptomatology in the years following service, the Board concludes that his reports concerning the history of his claimed bilateral knee disability (including any reports of a continuity of symptomatology in the years following service) are not credible. In addition, the preponderance of the competent, probative opinions on whether there was a relationship between the Veteran’s current bilateral knee disability and service or service-connected disabilities weigh against the claim. The physician who conducted the March 2011 VA examination opined that the Veteran’s bilateral knee disability was not caused by or a result of service. He reasoned that the Veteran’s service treatment records documented a serious left knee injury as a young child, that there was no documentation of serious injury to either knee during service, and that his separation examination was negative for any knee conditions. The objective evidence suggested that the Veteran’s left knee disability was most likely due to childhood injury with progression over time. His right knee disability was most likely due to aging/obesity/altered gait. In a March 2018 treatment record, J.A. Amundaray, M.D. reported that injuries suffered by the Veteran during service “could have affected his lower extremities pathology (osteoarthritis) and ultimately caused him to require total knee arthroplasty surgeries.” He further explained, however, that he did not have any documentation or medical records describing the Veteran’s injuries, and he recommended that the Veteran bring him such medical records in order to “establish objective causation of his lower extremities pathology.” The examiner who conducted the March 2019 VA examination opined, in pertinent part, that the Veteran’s right and left knee disabilities were not likely (“less likely than not”/“less than 50 percent probability”) incurred in or caused by service, to include the knee strain and abrasions in service. The examiner reasoned that the Veteran’s service treatment records showed treatment for knee abrasions in April 1979 and a right knee strain and abrasion in September 1979. The medical records following service showed treatment for a knee condition/surgery in April 2008, bilateral knee pain and arthroscopy in 2009, and a right total knee replacement in May 2017. There was a 29-year gap of medical evidence between the Veteran’s right knee strain in service and his later treatment/complaint of a right knee condition following service. There was no chronicity of care to show that the right knee strain continued after service and resulted in the Veteran’s current right knee disability. Overall, a nexus had not been established. While it was not disputed that trauma to a joint can increase the risk for subsequent development of arthritis, medical literature supports the fact that knee osteoarthritis with obesity is a major risk factor for total knee joint replacement. Clinically, it was likely (“at least as likely as not”/“50 percent or greater probability”) that the etiology of the Veteran’s right knee disability was his long-standing obesity, which was noted throughout his medical records. With respect to the left knee, the examiner explained that the Veteran reported a left knee injury prior to service. Therefore, a left knee disability clearly and unmistakably pre-existed service. The Veteran’s service treatment records showed a notation of a left knee fracture in 1970. Left knee problems were reported in February 1982 and the Veteran was treated for knee abrasions in April 1979. Medical records following service showed treatment for a knee condition/surgery in April 2008, bilateral knee pain and bilateral knee arthroscopy in 2009, and a left total knee replacement in or before 2009. Service treatment records were silent for treatment of a left knee musculoskeletal injury. There was a 26-year gap of medical evidence between service and later treatment and/or complaint of a left knee condition following service. Therefore, it was clear and unmistakable (obvious, manifest, and undebatable) that the pre-existing disease or injury was not aggravated during service. Moreover, the examiner explained that the Veteran’s current left knee disability was not likely (“less likely than not”/“less than 50 percent probability”) the result of his left knee injury prior to service or any aggravation during service. While it was not disputed that trauma to a joint can increase the risk for subsequent development of arthritis, medical literature supports the fact that obesity is a major risk factor for total knee joint replacement. Clinically, it was likely (“at least as likely as not”/“50 percent or greater probability”) that the etiology of the Veteran’s left knee disability was his long-standing obesity, which was noted throughout his medical records. In August 2020, a VA physician reviewed the Veteran’s claims file and opined in several opinions that the Veteran’s bilateral knee disability was not likely (“less likely than not”/“less than 50 percent probability”) proximately due to or the result of his service-connected back disability or bilateral lower extremity radiculopathy. He reasoned that the Veteran’s lumbar spine and bilateral radiculopathy were not sufficient to cause significant knee issues or to require knee surgeries in 2008 and 2009. Osteoarthritis and obesity were noted to be the primary etiology. The physician noted that the Veteran had a history of left knee fracture at age 10, but he also reasoned that lumbar spine difficulty would not skip over the hip to cause knee issues. In October 2020, a VA nurse practitioner reviewed the Veteran’s claims file and opined in several opinions that the Veteran’s bilateral knee disability was not likely (not “at least as likely as not”) proximately due to, the result of, or aggravated by his service-connected back disability and bilateral lower extremity radiculopathy. She explained in separate causation and aggravation rationales that the knee condition and the back/lower extremity radiculopathy disability were not medically related, that the knee condition was a separate entity entirely from the back disability/radiculopathy, and that the knee disability was unrelated to the back disability/radiculopathy. A thorough review of medical literature failed to demonstrate a causal relationship. There was no clear evidence from a review of orthopedic literature to suggest that an injury to one joint would have any significant impact on another or opposite uninjured joint or limb, unless the injury resulted in major muscle or nerve damage, causing partial or complete paralysis or shortening of the injured limb, resulting in length discrepancy of more than 5 centimeters so that the individual’s gait pattern has been altered to the extent that, clinically, there is an obvious Trendelenburg gait. There was no such gait documented in this case. Therefore, an aggravation nexus was not established. With respect to the Veteran’s contention that his obesity resulted from his service-connected disabilities, the nurse practitioner essentially opined that the Veteran’s obesity was not caused by his service-connected disabilities. She explained that the Veteran’s knee disability, back pain, and obesity were not medically related. The Veteran’s knee disability was a separate entity entirely from his back pain/obesity, and was unrelated to it. While orthopedic conditions can cause pain that prevents high impact activity, there are multiple activities, and other strategies, which can be used to prevent weight gain/obesity. There are many people in the general population who have been diagnosed with chronic orthopedic conditions and are not overweight/obese. Obesity is primarily due to consuming more calories that the body burns off, which is a choice. An orthopedic condition does not preclude all forms of exercise, as there are paraplegics who are not obese. The evidence showed that the Veteran was capable of losing weight, despite his low back disability, if he so chose. Overall, a nexus was not established. Moreover, the nurse practitioner opined that the Veteran’s bilateral knee disability was not likely (“less likely than not”/“less than 50 percent probability”) incurred in or caused by service. She reasoned that the Veteran’s knee condition during service was only acute and that there was no evidence of disruption to the articular surface of the joint at the time of injury during service. The degenerative joint disease of his knees was most likely a natural aging process or due to his morbid obesity. Also, there was no chronicity of care until 29 years after service. Therefore, a nexus to service or to the one year after his release from active duty was not established. The March 2011 opinion is of limited probative value because it does not address the evidence of knee problems in the Veteran’s service treatment records. Also, the opinion is partially based on a finding that the Veteran had pre-existing left knee disability prior to service. However, as explained above, the Veteran was presumed sound at service entrance. Dr. Amundaray’s March 2018 opinion is of minimal, if any, probative value because it is ambiguous and speculative. See Hood v. Shinseki, 23 Vet. App. 295, 296 (2009); Perman v. Brown, 5 Vet. App. 237, 241 (1993) (speculative or equivocal medical opinions may be considered “non-evidence” and have no probative value); Obert v. Brown, 5 Vet. App. 30, 33 (1993) (medical opinions that are speculative, general, or inconclusive in nature cannot support a claim). The March 2019 left knee opinion is also of little probative value because it is based on a finding that the Veteran had pre-existing left knee disability prior to service. The March 2019 right knee opinion and the August and October 2020 opinions do not explicitly acknowledge or discuss the Veteran’s reports of a continuity of knee symptomatology in the years following service. However, as explained above, any reports of a continuity of knee symptomatology are not deemed to be credible and an opinion based on such an inaccurate history would be inadequate. Coburn v. Nicholson, 19 Vet. App. 427, 432-433 (2006); Kowalski v. Nicholson, 19 Vet. App. 171, 179 (2006) (it is appropriate for the Board to find a medical opinion inadequate when it relies on lay statements that the Board has found not credible). Moreover, the March 2019 right knee opinion and the August and October 2020 opinions are based upon examination of the Veteran and/or a review of medical literature and the Veteran’s treatment records and reported history, and they are accompanied by specific rationales that are consistent with the evidence of record. In these opinions, the opinion providers acknowledged the knee problems documented in the Veteran’s service treatment records and explained why his claimed bilateral knee disability was not related to service and was not caused or aggravated by his service-connected back and lower extremity neurological disabilities. Also, it was explained why the Veteran’s obesity was not caused by his service-connected disabilities. Therefore, the March 2019 right knee opinion and the August and October 2020 opinions are adequate and entitled to substantial probative weight. See Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 304 (2008) (most of the probative value of a medical opinion comes from its reasoning; threshold considerations are whether the person opining is suitably qualified and sufficiently informed). Moreover, lay evidence may be competent on a variety of matters concerning the nature and cause of disability. However, the dispositive questions presented in this case (i.e., whether any relationship existed between the Veteran’s claimed bilateral knee disability and service or his service-connected disabilities) are questions as to internal medical processes which extend beyond an immediately observable cause-and-effect relationship that is of the type that the courts have found to be beyond the competence of lay witnesses. See Jandreau, 492 F.3d at 1377 (“sometimes the layperson will be competent to identify the condition where the condition is simple, for example a broken leg, and sometimes not, for example, a form of cancer”). Opinions as to whether there was a link between the Veteran’s bilateral knee disability and service (where there is no evidence of any knee problems for decades after service) or whether the bilateral knee disability was caused or aggravated by service-connected disabilities, are ones requiring specialized knowledge and testing to understand the complex nature of the body systems. The Veteran did not indicate that he had such experience, and the appellant does not contend that she has such experience. Their opinions on the question of nexus are therefore not competent evidence in this instance. There is no other evidence of a relationship between the Veteran’s bilateral knee disability and service or service-connected disabilities, and neither the appellant nor her representative have alluded to the existence of any such evidence. Thus, the preponderance of the evidence is against a finding that the Veteran’s bilateral knee disability had its onset in service or within the first post-service year, that it was otherwise related to service, or that it was caused or aggravated by service-connected disability. For the foregoing reasons, the preponderance of the evidence is against the claim. The benefit-of-the-doubt doctrine is therefore not for application, and service connection for bilateral knee disability is not warranted. 38 U.S.C. § 5107 (b); 38 C.F.R. § 3.102. Jonathan Hager Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board B. Elwood, Counsel The Board’s decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.