Citation Nr: 21009360 Decision Date: 02/22/21 Archive Date: 02/22/21 DOCKET NO. 15-21 510 DATE: February 22, 2021 ORDER Entitlement to an initial evaluation for left knee instability in excess of 20 percent under Diagnostic Code (DC) 5257 is denied prior to October 1, 2020. Entitlement to an initial evaluation in excess of 10 percent under DC 5003-5260 for left knee osteoarthritis based on limitation of flexion is denied from November 26, 2012 to May 13, 2014. The initial evaluation of 10 percent under for left knee osteoarthritis from May 14, 2014 to September 30, 2020 is changed from DC 5003-5260 to DC 5261. Entitlement to a separate 0 percent rating under DC 5260 is granted for limitation of flexion from May 14, 2014 to September 30, 2020. Entitlement to a rating in excess of 10 percent for left knee osteoarthritis is denied for the entire appeal period. FINDINGS OF FACT 1. Prior to October 1, 2020, the Veteran’s left knee instability did not cause him to experience severe recurrent subluxation or lateral instability. 2. From November 26, 2012 to May 13, 2014, the Veteran’s left knee osteoarthritis caused painful flexion limited at most to 100 degrees. 3. From May 14, 2014 to September 30, 2020, the Veteran’s left knee osteoarthritis caused him to experience extension limited to 10 degrees at most. 4. From May 14, 2014 to September 30, 2020, the Veteran’s left knee osteoarthritis caused him to experience flexion limited to 60 degrees at most. CONCLUSIONS OF LAW 1. The criteria for entitlement to an initial evaluation for left knee instability in excess of 20 percent prior to October 1, 2020 are not met. 38 U.S.C. § 1155; 38 C.F.R. § 4.71a, DC 5257. 2. From November 26, 2012 to May 13, 2014, the criteria for entitlement to an initial evaluation for left knee osteoarthritis based on limitation of flexion in excess of 10 percent are not met. 38 U.S.C. § 1155; 38 C.F.R. §§ 4.40, 4.59, 4.71a, DC 5003-5260. 3. From May 14, 2014 to September 30, 2020, the criteria for entitlement to an initial evaluation of 10 percent for left knee osteoarthritis based on limitation of extension are met. 38 U.S.C. § 1155; 38 C.F.R. §§ 4.71a, DC 5261. 4. From May 14, 2014 to September 30, 2020, the criteria for entitlement to an initial 0 percent evaluation for left knee osteoarthritis based on limitation of flexion are met. 38 U.S.C. § 1155; 38 C.F.R. §§ 4.71a, DC 5260. 5. For the entire appeal period, the criteria for a rating in excess of 10 percent for osteoarthritis of the left knee are not met under any DC. 38 U.S.C. § 1155; 38 C.F.R. §§ 4.71a, DCs 5003, 5260, 5261. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran had active duty service from July 1980 to July 1983. This appeal comes to the Board of Veterans’ Appeals (Board) from a rating decision dated November 2013 issued by a Department of Veterans Affairs (VA) Regional Office (RO). This decision granted service connection for a left knee disability effective November 26, 2012, assigning two initial ratings: 20 percent for instability under DC 5257, and 10 percent for osteoarthritis under DC 5003-5260. The Veteran timely appealed. The Veteran’s appeal has previously been before the Board. In July 2018, the Board remanded the Veteran’s left knee disability claims to the AOJ for additional development. On October 1, 2020, the Veteran underwent a total left knee replacement. In a rating decision dated January 2021, the RO recharacterized the disability to reflect the knee replacement. The left knee instability rating was recharacterized as “evaluation of status post left total knee replacement,” changed the DC from 5257 to 5055, and increased the rating from 20 percent disabling to 100 percent effective October 1, 2020. The 10 percent rating under DC 5003-5260 for osteoarthritis was discontinued effective October 1, 2020. As the 100 percent rating is maximum schedular benefit available, the Board will only discuss the appeal period from November 26, 2012 to September 30, 2020. Increased Ratings Disability ratings are determined by applying the criteria set forth in the VA Schedule for Rating Disabilities (rating schedule), found in 38 C.F.R. Part 4. Disability ratings are intended to compensate impairment in earning capacity due to a service-connected disorder. 38 U.S.C. § 1155. If there is a question as to which evaluation to apply to the Veteran’s disability, the higher evaluation will be assigned if the disability picture more nearly approximates the criteria for that rating. Otherwise, the lower rating will be assigned. 38 C.F.R. § 4.7. When reasonable doubt arises as to the degree of disability, such doubt will be resolved in the Veteran’s favor. 38 C.F.R. § 4.3. Pertinent regulations do not require that all cases show all findings specified by the Rating Schedule, but that findings sufficiently characteristic to identify the disease and the resulting disability and coordination of rating with impairment of function. 38 C.F.R. § 4.21. Therefore, the Board has considered the potential application of various other provisions of the regulations governing VA benefits, whether or not they were raised by the Veteran, as well as the entire history of his disability in reaching its decision. Schafrath v. Derwinski, 1 Vet. App. 589, 595 (1991). Neither the Veteran nor the record raise the applicability of DCs other than those discussed herein. Evidence In a statement in support of claim dated December 2012, the Veteran wrote, Over the course of years after military service these conditions always had an effect on me. Suffering from severe pain, swelling, fluid built up, slow circulation, and difficulty walking. At times my left knee would slip but through it all I know as I get older it’s going to get worse! The pain is constantly there. Objective evidence shows that during the November 2013 VA examination, the examiner noted that the Veteran’s diagnoses included left knee osteoarthritis and moderate medial instability of the left knee. The Veteran noted that as the years passed by, he always had problems in the left knee, pain with ambulation, stiffness, and slipping. He used a brace. Pain on an average day was noted as eight out of 10 and on a rainy or cold day nine to 10 out of 10. The Veteran reported that flare-ups impacted the function of the knee and/or lower leg which he described as “it swells more and it stiffens up.” Flexion of the left knee was recorded as 120 degrees. Extension in the left knee showed no objective evidence of painful motion. The Veteran had functional loss, functional impairment or additional limitation of range of motion of the knee after repetitive use. Contributing factors of the disability were noted as less movement than normal, weakened movement, excess fatigability, incoordination, impaired ability to execute skilled movements smoothly, pain on movement, swelling, deformity, instability of station, disturbance of locomotion, and interference with sitting, standing, and weight-bearing. Joint stability tests for anterior instability and posterior instability were recorded as normal. Medial-lateral instability in the left knee was recorded as 2+. An April 2014 medical treatment record recorded that the Veteran’s left knee pain had become worse over the past year. The pain was rated as nine out of 10 and was felt mostly in the front and lateral aspect of the knee, which was aggravated by walking and stairs. He was able to walk three blocks without a cane. Left knee range of motion was noted as 0 to 100 degrees. There was good AP stability. He also had an injection in his left knee with a corticosteroid. In a Notice of Disagreement (NOD) dated April 2014, the Veteran wrote, Due to new evidence of damage in my left knee. As my orthopedic doctor discovered, the cushion in my left knee is wearing down, soon it will be bone rubbing bone, which will lead to a knee replacement. I am experiencing severe pain as I continue to walk on the left knee the pressure is so intense it’s now causing me to shift more on the right foot…Some days it’s hard to walk or stand on both legs. At the present time, my orthopedic doctor is giving me cortisone shots to help ease the intense pain. The Veteran underwent another VA examination in May 2014 for his knees. During the examination, he complained of worsening pain. He received an injection on April 16, which only helped temporarily. His pain level on an average was a seven out of 10 and was described as burning or sharp, and it flared to a 10 out of 10. There was no clicking, but he had swelling, buckling, and stiffness. He reported that flare-ups impacted the function of the knee and/or lower leg which were described as “I have to take some pain medication. I elevate it and I put ice on it.” Left knee flexion was noted as 60 degrees and objective evidence of painful motion began at 10 degrees. Left knee extension ended at 10 degrees and painful motion on extension began at 10 degrees. Contributing factors of the disability were noted as less movement than normal, weakened movement, incoordination, impaired ability to execute skilled movements smoothly, pain on movement, swelling, deformity, instability of station, disturbance of locomotion, and interference with sitting. Joint stability tests for anterior instability and posterior instability were recorded as normal. Medial-lateral instability in the left knee was recorded as 2+. Functional limitations were described as ambulation two blocks, no running, kneeling, jumping, squatting, stooping, or stairs. A September 2014 medical treatment record documented range of motion in the left knee was 0 to 100 degrees with good AP stability. Medical treatment records ranging throughout the entirety of the appeal period record pain in the left knee and note injections into the left knee for treatment. In a statement in support of claim dated January 2015, the Veteran provided, “It was determined that I will need left knee surgery due to deteriorating of the knee and other complications even after treatment – in which I would be out of work for three months to recover. The surgery date is scheduled to be on June 15, 2015.” A treatment record dated December 2015 noted left knee range of motion was 0 to 100 degrees, and noted the left knee was very painful at extremes. In January 2016, a private physician provided, This is to certify that [the Veteran] is now scheduled for left knee osteotomy for deformity corrections followed by total knee replacement approximately six to 12 months later. First operation is planned for February 2016. Each operation may have three to six month recovery period where patient may not be able to work. The Veteran underwent an osteotomy of the left distal femur in February 2016. Medical treatment records following the Veteran’s February 2016 surgery noted that the Veteran was healing well from his surgery. A February 2016 treatment record noted that he reported pain in his left knee as a nine out of 10. He was able to walk two blocks and endorsed a significant limp. Another February 2016 treatment record documented pain in the left knee was an eight out of 10. The quality of pain was throbbing and was relieved by medications and position. A February 2016 treatment record recorded that left knee pain was rated as seven out of 10 and knee range of motion was 10 to 70 degrees. A March 2016 treatment record noted left knee range of motion was 5 to 85 degrees. The Veteran was also fitted for knee orthosis. In June 2016, knee range of motion was noted as 0 to 100 degrees. In October 2016, knee range of motion was recorded as 0 to 125 degrees. A March 2018 treatment record provided, “lacks 5 degrees extension and 95 degrees flexion in left knee.” In July 2018, the Board remanded the Veteran’s left knee disability claims for another examination as he had undergone an osteotomy of the left distal femur. In November 2018, active range of motion of the left knee was recorded as 3 to 70 degrees. In the January 2019 VA examination, the Veteran reported that his left knee pain was a six to seven out of 10 at the time of the examination. He noted that he experienced constant pain in his left knee, which was aggravated by prolonged walking and standing. He had left femur surgery on February 1, 2016, but still had constant left knee pain. He received injections to the left knee which helped temporarily. He also took medication as needed for the pain. He used a straight cane. He was able to walk two blocks but was unable to run. He also had to change positions from sitting to standing as needed. He did not report flare-ups. He reported functional loss or functional impairment described as not being able to run and ability to only walk two blocks at a time. Flexion in the left knee was recorded as 10 to 60 degrees. Extension of the left knee was noted as 60 to 10 degrees. Additional contributing factors of the disability included recurrent swelling, valgus deformity, and antalgic gait with straight cane. There was no history of recurrent subluxation or lateral instability in the left knee. Joint stability testing showed anterior, posterior, and lateral instability were normal. Medial instability was recorded as 2+. Residuals from the Veteran’s left distal femur lateral opening wedge corrective osteotomy in February 2016 were described as pain and reduced range of motion. In the November 2019 VA examination, the Veteran reported knee pain as a six on a 0 to 10 scale. He was in constant pain, which was aggravated by prolonged walking and standing. He took Tylenol and Naproxen for his knee pain. There were no recent knee injections. He was able to walk two blocks but was unable to run. He did not report flare-ups of the left knee. The Veteran reported functional loss or functional impairment described as avoiding prolonged walking and standing. Flexion in the left knee was 10 to 60 degrees and extension was 60 to 10 degrees. Pain was noted on exam but did not result in or cause functional loss. There was no history of recurrent subluxation or lateral instability in the left knee. Joint stability testing was performed. Anterior, posterior, and lateral instability were all normal. Medial instability was noted as 2+. He used a brace occasionally and a cane regularly. In a NOD dated June 2020, the Veteran wrote, I have a handicap because I have no lifting ability of my left leg to wash my feet on my own. My wife has to assist me in washing my left feet. I’m very much off balance. Sometimes I stumble into things. My pain level has gotten worse at a ten. [I am] taking different types of pain medication to assist in the agony of my situation. [My] left lower leg continue[s] to swell. I have a titanium plate that is attached to my left femur all the way down to my left knee that has about six screws embedded into my left knee in which [have] been set up for knee replacement attachment…Getting dressed for me is not as easy when putting on my pants, I have to drop it on the floor to put my foot in the pant. In a lay statement dated June 2020, the Veteran’s wife provided, I’m writing on my husband’s behalf as a witness to his pain and lack of movement in his left knee that the titanium has been placed. [He] struggles very hard just to walk to the subway for work. I…have to help him dress every day and undress every night. When he showers, I have to wash his lower legs and feet of [the] left knee because [he] is unable to do this function now. [He] cannot lift the left knee and leg with the titanium at all now by himself, when bathing or dressing without tremendous pain. [His] pain levels since his left knee went out on him is always a 10. He aches all the time especially when he has to walk or climb stairs. [He] is unable to run, jump or walk fast now. [His] pain is very real and uncomfortable for him on every level. 1. Entitlement to an initial evaluation for left knee instability in excess of 20 percent disabling prior to October 1, 2020 The Veteran generally asserts that the assigned 20 percent rating under DC 5257 does not adequately reflect the severity of his left knee instability prior to October 1, 2020. The period on appeal begins on November 26, 2012, the effective date for the award of service connection for the Veteran’s left knee instability. The Veteran’s left knee instability is rated under 38 C.F.R. § 4.71a, DC 5257, for other impairment of the knee. Under DC 5257, a 10 percent rating is warranted for slight recurrent subluxation or lateral instability. A 20 percent rating is warranted for moderate recurrent subluxation or lateral instability. A 30 percent rating is warranted for severe recurrent subluxation or lateral instability. 38 C.F.R. § 4.71a, DC 5257. According to MERRIAM WEBSTER’S COLLEGIATE DICTIONARY 999 (11th Ed. 2007), “slight” means small in amount. “Moderate” means limited in scope or effect. “Severe” means very painful or harmful or of a great degree. Objective medical evidence is not required to establish lateral knee instability under DC 5257, so objective medical evidence cannot be categorically found more probative than lay evidence with respect to this DC. See English v. Wilkie, 30 Vet. App. 347, 352-53 (2018). The Board finds that the preponderance of the evidence is against a rating in excess of 20 percent for left knee instability prior to October 1, 2020. The Board has carefully considered the Veteran’s reports about his knee being in constant pain and the limitations that it causes him. However, overall, the lay and medical evidence indicates that the left knee instability symptoms have varied and do not suggest the presence of symptoms more nearly approximating severe recurrent subluxation or lateral instability. Every stability test performed upon examination, to include Lachman’s (anterior instability), drawer (posterior instability), and varus pressure (lateral instability) confirmed normal left knee stability in all four of his VA examinations. In all four of his VA examinations, the Veteran’s valgus pressure (medial instability) was noted as 2 plus, with the scale ranging from normal to 3 plus. As the medial instability was not a 3 plus, this test shows a moderate rather than severe disability. As the record does not show any evidence of severe recurrent subluxation or lateral instability, consideration of assignment of a higher evaluation based either on recurrent subluxation or lateral instability is not warranted. On the contrary, all four VA examiners found that there was no history of recurrent subluxation or lateral instability in the left knee. In this case, the lay and medical evidence show some instability but not severe instability. Accordingly, as the record does not show a severe level of lateral instability or subluxation of the left knee, the criteria for a rating in excess of 20 percent under DC 5257 are not met at any time during the course of the appeal. In summary, an initial rating greater than 20 percent is not warranted for instability of the left knee prior to October 1, 2020. 2. Entitlement to an initial evaluation for left knee osteoarthritis based on limitation of flexion under DC 5003-5260 in excess of 10 percent from November 26, 2012 to May 13, 2014 3. Entitlement to an initial evaluation of 10 percent for left knee osteoarthritis based on limitation of extension under DC 5261 from May 14, 2014 to September 30, 2020 4. Entitlement to an initial noncompensable evaluation for left knee osteoarthritis based on limitation of flexion from May 14, 2014 to September 30, 2020 The Veteran generally asserts that the assigned 10 percent rating under DCs 5003-5260 does not adequately reflect the severity of his left knee osteoarthritis. The period on appeal begins on November 26, 2012, the effective date for the award of service connection for the Veteran’s left knee osteoarthritis. Traumatic arthritis, substantiated by X-ray findings, is rated as degenerative arthritis. 38 C.F.R. § 4.71a, DC 5010. Degenerative arthritis established by X-ray findings will be rated based on limitation of motion under the appropriate DC for the specific joint or joints involved. When, however, the limitation of motion of the specific joint or joints involved is noncompensable under the appropriate DCs, a rating of 10 percent is for application for each such major joint or group of minor joints affected by limitation of motion, to be combined, not added under DC 5003. Limitation of motion must be objectively confirmed by findings such as swelling, muscle spasm, or satisfactory evidence of painful motion. 38 C.F.R. § 4.71a, DC 5003. Limitation of flexion of the leg is evaluated as follows: a noncompensable rating is warranted for flexion limited to 60 degrees. A 10 percent rating is warranted for flexion limited to 45 degrees. A 20 percent rating is warranted for flexion limited to 30 degrees. A 30 percent rating is warranted for flexion limited to 15 degrees. 38 C.F.R. § 4.71a, DC 5260. Limitation of extension of the leg is evaluated as follows: extension limited to 45 degrees (50 percent); extension limited to 30 degrees (40 percent); extension limited to 20 degrees (30 percent); extension limited to 15 degrees (20 percent); extension limited to 10 degrees (10 percent); and extension limited to 5 degrees (0 percent). 38 C.F.R. § 4.71a, DC 5261. Separate ratings under DCs 5260 and 5261 may be assigned for disability of the same joint, if none of the symptomatology on which each rating is based is duplicative or overlapping. VAOPGCPREC 9-04; 69 Fed. Reg. 59990 (2004); 38 C.F.R. § 4.14. VA regulations set forth at 38 C.F.R. §§ 4.40, 4.45, 4.59 provide for consideration of functional impairment due to pain on motion when evaluating the severity of a musculoskeletal disability. The Court has held that a higher rating can be based on “greater limitation of motion due to pain on use.” DeLuca v. Brown, 8 Vet. App. 202, 206 (1995). Any such functional loss must be “supported by adequate pathology and evidenced by the visible behavior of the claimant.” See 38 C.F.R. § 4.40. The assignment of a particular DC is “completely dependent on the facts of a particular case.” See Butts v. Brown, 5 Vet. App. 532, 538 (1993). One DC may be more appropriate than another based on such factors as the Veteran’s relevant medical history, his current diagnosis, and demonstrated symptomatology. Any change in DC by a VA adjudicator must be specifically explained. See Pernorio v. Derwinski, 2 Vet. App. 625, 629 (1992). November 26, 2012 to May 13, 2014 During this stage, the Veteran is currently rated as 10 percent disabling under 5003-5260 for left knee osteoarthritis based on limitation of flexion. The Board finds this is appropriate to compensate painful but noncompensable limitation of motion of flexion of the knee. The evidence shows that prior to May 14, 2014, neither the Veteran’s limitation of flexion nor extension met the criteria for even a zero percent rating. That is, from November 26, 2012 to May 13, 2014 his flexion was not limited to 60 degrees or less, and his extension was normal. At most, the knee was limited to 100 degrees of flexion. See November 2013 VA examination report; April 2014 medical treatment record. However, the Veteran’s lay reports make it clear that he experienced painful motion of the knee, and the November 2013 VA examiner noted no pain in extension, but pain during flexion. Therefore, it is appropriate for the 10 percent rating to be assigned under DC 5003-5260 for painful but noncompensable flexion. The Veteran is competent to report his perceived level of pain and functional impairment and his complaints are acknowledged. On review, the Board does not find adequate pathology to support a higher rating based on functional impairment due to pain on motion or other factors. Considering the duration and severity of the vast majority of reported flare-ups between November 26, 2012 and May 13, 2014, along with the examination findings during the November 2013 examination, the disability picture does not more nearly approximate flexion limited to 30 degrees, even with pain and on flare-ups, and a rating greater than 10 percent is not warranted during this period. The Veteran underwent one VA examination during the period from November 26, 2012 to May 13, 2014. Range of motion testing during this stage has consistently shown active left knee flexion as 100 degrees or greater. There is no indication that his flexion is limited to 30 degrees or less during flare-ups. Additionally, range of motion testing consistently shows full extension during this period. The Veteran’s range of motion must be limited to 30 degrees flexion, or 15 degrees extension, to warrant a rating higher than 10 percent; there is no evidence that these criteria are met for a higher rating under DCs 5260 or 5261 for this stage. The Board does not disturb the current 10 percent rating under DC 5003-5260 for this stage and denies a rating in excess of 10 percent. May 14, 2014 to September 30, 2020 The May 14, 2014 VA examination reveals the first compensable limitation of motion. Specifically, the Veteran’s extension was limited to 10 degrees, warranting a 10 percent disability rating under DC 5261 for limitation of extension. As explained below, throughout the appeal period the Veteran meets the criteria for a compensable rating only under DC 5261 for limitation of extension. Once the Veteran’s disability reached a compensable limitation of motion, the rating under DC 5003-5260 for noncompensable painful limitation of motion was no longer appropriate. For this reason, the Board changes the DC for the 10 percent rating for this stage from DC 5003-5260 to DC 5261, effective May 14, 2014. Concerning limitation of flexion, the May 2014 VA examination showed left knee flexion limited to 60 degrees. This is the first measurement of flexion that meets the schedular criteria for assignment of a separate rating under DC 5260. Thus, the Board also grants a 0 percent rating under DC 5260 from May 14, 2014 to September 30, 2020. In order for the next higher ratings to be warranted under either of these DCs, extension must be limited to 15 degrees, and flexion must be limited to 45 degrees. The evidence does not reflect this limitation, even with flare-ups. In making this determination the Veteran’s complaints of pain and functional impairment are acknowledged. The record does not contain adequate pathology to support a higher rating based on limitation of motion due to pain on motion or other factors. As noted above, during his May 2014 VA examination, left knee extension ended at 10 degrees and painful motion on extension began at 10 degrees. Flexion was limited to 60 degrees. While pain on flexion was noted at 10 degrees, the examination shows that the Veteran was still able to flex to 60 degrees, including on repetition. The functional loss reported for the knee included needing to elevate and ice and limited ambulation, but there were no reports of additional limitation of motion during flare-ups or due to pain. Private treatment records reflect the following: A February 2016 treatment record recorded knee range of motion as 10 to 70 degrees. A March 2016 treatment record noted left knee range of motion was 5 to 85 degrees. In June 2016, knee range of motion was noted as 0 to 100 degrees. In October 2016, knee range of motion was recorded as 0 to 125 degrees. In a March 2018 treatment record, the Veteran lacked 5 degrees extension. In November 2018, active range of motion of the left knee was recorded as 3 to 70 degrees. In both the January 2019 and November 2019 VA examinations, extension in the left knee was consistently limited to 10 degrees. In both the January 2019 and November 2019 VA examinations, flexion in the left knee was recorded as 10 to 60 degrees. On review, from May 14, 2014 to September 30, 2020 range of motion testing has consistently shown left knee flexion as 60 degrees or greater, and extension to 10 degrees or less. Thus, a higher rating is not warranted under either DC. In making this determination the Veteran’s competent complaints of pain and functional impairment are acknowledged. The record does not contain adequate pathology to support a higher rating based on functional impairment due to pain on motion or other factors. Mitchell, DeLuca, and 38 C.F.R. §§ 4.40 and 4.45 do not require the assignment of a higher schedular disability rating where the functional limitation due to pain does not result in limitation of motion sufficient to meet the requirements of the next higher disability rating. See Thompson v. McDonald, 815 F.3d 781, 785-86 (Fed. Cir. 2016) (holding that §§ 4.40 and 4.45 do not supersede the requirements for a higher disability rating specified in § 4.71a). Summary The initial 10 percent rating for noncompensable painful motion from November 26, 2012 to May 13, 2014 is undisturbed. The initial 10 percent rating for osteoarthritis of the left knee from May 14, 2014 to September 30, 2020 is changed from DC 5003-5260 to DC 5261. A separate noncompensable rating for limitation of flexion is granted under DC 5260 effective May 14, 2014 to September 30, 2020. (Continued on the next page)   An initial evaluation in excess of 10 percent for left knee osteoarthritis is denied. LAURA E. COLLINS Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board K. Bristor 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.