Citation Nr: 21062688 Decision Date: 10/08/21 Archive Date: 10/08/21 DOCKET NO. 06-06 996 DATE: October 8, 2021 ORDER Entitlement to a disability rating in excess of 20 percent for left patellofemoral chondrosis (excluding periods of temporary 100 percent ratings under 38 C.F.R. § 4.30) is denied. From June 5, 2003, to December 17, 2007, entitlement to a separate disability rating of 10 percent, but no higher, based on painful motion of the left knee is granted. From December 17, 2007, entitlement to a disability rating of 30 percent, but no higher, for limited extension of the left knee is granted. From January 7, 2012, entitlement to a disability rating of 20 percent, but no higher, for limited flexion of the left knee is granted. REMANDED Entitlement to service connection for a left shoulder disability is remanded. Entitlement to service connection for diabetes mellitus, to include as secondary to a service-connected knee disability or post-traumatic stress disorder (PTSD) is remanded. FINDINGS OF FACT 1. Prior to January 7, 2012, the Veteran's recurrent subluxation or instability was manifested by moderate symptoms. 2. From June 5, 2003, to December 17, 2007, the Veteran's left knee disability was manifested by painful motion but not flexion limited to 45 degrees or extension limited to 10 degrees. 3. From December 17, 2007, the Veteran's left knee disability was manifested by extension limited to 20 degrees. 4. From January 7, 2012, the Veteran's left knee disability was manifested by flexion limited to 30 degrees. 5. Beginning on January 7, 2012, the combined disability rating for the Veteran's left knee is 60 percent. CONCLUSIONS OF LAW 1. The criteria for entitlement to a disability rating in excess of 20 percent for left patellofemoral chondrosis have not been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.20, 4.59, 4.71a, Diagnostic Code 5257. 2. From June 5, 2003, to December 17, 2007, the criteria for entitlement to disability rating of 10 percent, but no higher, for painful motion of the left knee are met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.20, 4.59, 4.71a, Diagnostic Codes 5260, 5261. 3. From December 17, 2007, entitlement to a disability rating of 30 percent, but no higher, for limited extension of the left knee have been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.20, 4.59, 4.71a, Diagnostic Codes 5010, 5261. 4. From January 7, 2012, the criteria for entitlement to a disability rating of 20 percent, but no higher, for limited flexion of the left knee have been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.20, 4.59, 4.71a, Diagnostic Codes 5010, 5260. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty in the United States Army from August 1988 to December 1989. This matter comes before the Board of Veterans' Appeals (Board) on appeal from rating decisions by a Department of Veterans Affairs (VA) Regional Office (RO). At the outset, the Board will provide a brief overview of this matter's extensive procedural history. These matters were first before the Board in 2011, when the Veteran testified before a now-retired Veterans Law Judge. In a November 2011 Board decision, the Board remanded the Veteran's claims to obtain outstanding treatment records, as well as to schedule VA examinations with respect to his left knee disability, left shoulder disability, and diabetes mellitus. With respect to the examinations for the left shoulder, the Board requested for a physician "knowledgeable in orthopedics" to perform the examination. Thereafter, the RO obtained new VA examinations and medical opinions, including an examination performed by a medical doctor whose specialty was not identified and an opinion on the left shoulder provided by a nurse practitioner. In a January 2013 Board decision, the Board once more remanded these matters for additional development. Pertinently, the Board asked for new VA examinations to be scheduled with respect to his left knee disability, left shoulder disability, and diabetes mellitus. The Board did not specify whether the examinations were to be done by specialists. Subsequently, the matter returned to the Board in 2016. In a November 2016 decision, the Board noted that the Veteran had been notified that the Veterans Law Judge who took testimony at the 2011 hearing was no longer employed at the Board but had not requested another hearing. In its remand directives, the Board requested for the RO to again schedule new VA examinations with respect to the left knee and obtain addendum medical opinions with respect to the left shoulder and diabetes mellitus. Without indicating its precise rationale for doing so, the Board specified in its remand directives that an orthopedic specialist should perform the examination and provide opinions for the left knee and left shoulder and that an endocrinologist should provide the opinion for diabetes mellitus. On remand, the RO obtained a series of opinions from a VA examiner who identified himself as an internist. The matters returned to the Board in December 2018, at which time the Board remanded the claims solely because the opinions had not been provided by an orthopedic specialist or endocrinologist. In its remand instructions, the Board directed the RO to obtain opinions and an examination from specialists. Subsequently, the RO provided the Veteran with new VA examinations performed by a nurse practitioner. The matters returned to the Board in July 2020, at which time the Board remanded the claims once again. In its decision, the Board noted that the nurse practitioner was not an endocrinologist or orthopedic specialist, and that remand is warranted to obtain VA examinations from these specialists. Notably, with respect to the left shoulder and left knee (but not diabetes mellitus), the Board stated in its remand directives that if a specialist was not available or not necessary, the report must contain reasoning for this. The remand decision also indicated that the examination reports were inadequate in various respects. Thereafter, the RO attempted on various occasions to request for new VA examinations to be scheduled by a contractor with the specific specialists listed in the Board's prior remand. As indicated in various examination requests, however, the contractor's agreement with VA did not require for specialists to perform orthopedic or diabetes mellitus examinations, and no specialists were available to perform the examinations at that time. As a result, a doctor specializing in occupational medicine performed the VA examinations on remand. The matter now returns to the Board. A remand by the Board confers a right to compliance with the directives of that remand. Stegall v. West, 11 Vet. App. 268 (1998). The Board notes, however, that while substantial compliance with remand directives is required, strict compliance is not. D'Aries v. Peake, 22 Vet. App. 97, 105 (2008) (finding there was no error where VA obtained a medical opinion from a neurologist, rather than an internal medicine specialist, as specified in a Board order). Contrary to the Board's previous remand orders, the performance of an examination by a non-specialist alone is insufficient to show that there has not been substantial compliance with a previous remand order. See Hansen v. Shinseki, 2012 U.S. App. Vet. Claims LEXIS 1505. Here, the RO has attempted to schedule examinations with specialists but was unable to do so because specialists were unavailable. Nonetheless, the examiners who were available performed the requested examinations and provided the requested opinions. See Dyment v. West, 13 Vet. App. 141, 146-47 (1999) (holding that there was no Stegall violation where an examiner made the ultimate determination required by the Board's remand). Moreover, there is no indication that the various examiners who have performed the VA examinations or provided VA opinions to date are not competent to provide these specific medical opinions regarding the etiology of diabetes mellitus or a left shoulder disability, or to perform an examination regarding the severity of left knee symptoms. Indeed, the Board is entitled to assume the competence of VA examiners. See Cox v. Nicholson, 20 Vet. App. 563, 569 (2007). The Veteran has not challenged, and the record does not indicate that there is any deficiency in, the credentials of these examiners. Ultimately, the Board finds that, to the extent that the VA examinations obtained were performed by medical professionals who were not orthopedic specialists or endocrinologists, there has been substantial compliance with the Board's previous remand directives. The Board also notes that the record indicates that the Veteran stopped working in approximately 2015 due to pain in his knees and difficulty walking or bending. It is the established VA policy that all veterans who are unable to secure and follow a substantially gainful occupation by reason of service-connected disability or disabilities shall be rated totally disabled. 38 C.F.R. § 4.16. A finding of total disability is appropriate "when there is present any impairment of mind or body which is sufficient to render it impossible for the average person to follow a substantially gainful occupation." See 38 C.F.R. §§ 3.340(a)(1), 4.15. In addition, VA's duty to maximize a claimant's benefits requires consideration of whether his disabilities establish entitlement to an even higher rate of compensation called "special monthly compensation" (SMC) under 38 U.S.C. § 1114. SMC(s) is available to veterans who have a single disability rated as total, and a separate disability(ies) that amounts to 60 percent. 38 U.S.C. § 1114(s). Here, however, the Veteran has been awarded a rating of 100 percent, effective June 22, 2011, for PTSD, as well as SMC at the (s) rate from that date. Given that the Veteran already has a disability rated at 100 percent disabling, the issue of TDIU is only considered to not be moot when it can assist in obtaining SMC(s). See Buie v. Shinseki, 24 Vet. App. 242 (2010); Bradley v. Peake, 24 Vet. App. 242 (2010). As set forth above, however, the Veteran is already receiving SMC(s) from June 22, 2011. This combination of a 100 percent schedular rating and SMC(s) renders moot the issue of TDIU from June 22, 2011. Moreover, the record indicates that prior to June 22, 2011, the Veteran was employed by the United States Postal Service. As such, the issue of TDIU is not reasonably raised by the record prior to June 22, 2011. As a final matter, the Board notes that this matter has been advanced on the Board's docket pursuant to 38 C.F.R. § 20.800(c). Increased Rating The Veteran was initially awarded service connection for patellofemoral chondrosis in the left knee, effective February 15, 1991, which was rated at 20 percent disabling under diagnostic code 5257. In June 2003, he filed a claim for an increased disability rating for his left knee disability. During the pendency of his appeal, the RO awarded a separate 10 percent rating under diagnostic code 5010-5260 based on arthritis with noncompensable limitation of motion from September 4, 2004. Then, in an October 2010 rating decision, the RO switched the applicable diagnostic code to 5010-5261 and increased the separate rating to 20 percent from October 17, 2010, based on limitation of extension of the left knee. In a subsequent June 2014 rating decision, the RO awarded another separate 20 percent rating under diagnostic code 5010-5260 from June 3, 2013, for limitation of flexion of the left knee. As these actions did not constitute a full grant of the benefits sought on appeal, the Veteran's claim remains on appeal before the Board. AB v. Brown, 6 Vet. App. 35 (1993). Disability ratings are determined by evaluating the extent to which a veteran's service-connected disability adversely affects his or her ability to function under the ordinary conditions of daily life, including employment, by comparing his or her symptomatology with the criteria set forth in the Schedule for Rating Disabilities. The percentage ratings represent as far as can practicably be determined the average impairment in earning capacity resulting from such diseases and injuries and the residual conditions in civilian occupations. Generally, the degree of disabilities specified are considered adequate to compensate for considerable loss of working time from exacerbation or illness proportionate to the severity of the several grades of disability. 38 U.S.C. § 1155; 38 C.F.R. § 4.1. Separate diagnostic codes identify the various disabilities and the criteria for specific ratings. If two disability evaluations are potentially applicable, the higher evaluation will be assigned to the disability picture that more nearly approximates the criteria required for that rating. Otherwise, the lower rating will be assigned. 38 C.F.R. § 4.7. Any reasonable doubt regarding the degree of disability will be resolved in favor of the Veteran. 38 C.F.R. § 4.3. However, the evaluation of the same disability under various diagnoses, known as pyramiding, is to be avoided. 38 C.F.R. § 4.14. Where, as here, entitlement to service connection has already been established and an increase in the disability rating is at issue, it is the present level of disability that is of primary concern. Francisco v. Brown, 7 Vet. App. 55, 58 (1994). However, staged ratings are appropriate for an increased rating claim if the factual findings show distinct time periods where the service-connected disability exhibited symptoms that would warrant different ratings. See Hart v. Mansfield, 21 Vet. App. 505 (2007). In deciding claims, it is the Board's responsibility to evaluate the entire record on appeal. See 38 U.S.C. § 7104(a). Although the Board has an obligation to provide reasons and bases supporting this decision, there is no need to discuss each piece of evidence submitted by the appellant or on his behalf. See Gonzales v. West, 218 F.3d 1378 (Fed. Cir. 2000). Rather, the Board's analysis below will focus specifically on what evidence is needed to substantiate the claim and what the evidence in the claims file shows, or fails to show, with respect to the claim. See Timberlake v. Gober, 14 Vet. App. 122, 128-30 (2000). Disability of the musculoskeletal system is primarily the inability, due to damage or inflammation in parts of the system, to perform normal working movements of the body with normal excursion, strength, speed, coordination and endurance. Functional loss may be due to pain supported by adequate pathology and evidenced by visible behavior of the claimant undertaking the motion. See 38 C.F.R. § 4.40. The factors of disability affecting joints are reduction of normal excursion of movements in different planes, weakened movement, excess fatigability, swelling and pain on movement. See 38 C.F.R. § 4.45. When evaluating disabilities of the joints, the Rating Schedule provides for consideration of additional functional impairment due to pain, weakness, fatigue, incoordination, and lack of endurance when assigning evaluations. See 38 C.F.R. §§ 4.40, 4.45, 4.59. Effective February 7, 2021, VA amended portions of its regulations governing musculoskeletal disabilities. The Board may not apply a current regulation prior to its effective date unless explicitly provided for. Nonetheless, the Board may apply prior versions of the applicable diagnostic code to the period on or after the effective date of the new diagnostic code if the prior versions were in effect during the pendency of the appeal, like here. As such, the Board is permitted to evaluate the Veteran's left knee disability under both earlier and current diagnostic codes, as of their effective dates, to determine which version would warrant the highest rating. As set forth in more detail below, however, it is unnecessary to evaluate his left knee disability using the current, amended diagnostic codes, because the Veteran's combined rating for his left knee reached 60 percent prior to February 7, 2021, and a combined rating in excess of 60 percent is not permitted. See 38 C.F.R. § 4.68 (noting the combined rating for a disability shall not exceed the rating for amputation at the elective level of the extremity were amputation to be performed). As relevant here, amputation of the leg at the knee warrants a 60 percent rating under diagnostic code 5162. 38 C.F.R. § 4.71a. Normal range of motion of the knee is 0 degrees of extension and 140 degrees of flexion. 38 C.F.R. § 4.71a, Plate II. The relevant rating criteria include diagnostic code 5260, which governs limitation of flexion of the leg. A noncompensable rating is warranted for flexion limited to 60 degrees, while a 10 percent rating is available for flexion limited to 45 degrees, a 20 percent rating for flexion limited to 30 degrees, and a 30 percent rating for flexion limited to 15 degrees. See 38 C.F.R. § 4.71a, Diagnostic Code 5260. The rating criteria also include diagnostic code 5261, which discusses limitation of extension of the leg. A noncompensable rating is warranted for extension limited to 5 degrees, while a 10 percent rating is available for extension limited to 10 percent, a 20 percent rating for extension limited to 15 degrees, a 30 percent rating for extension limited to 20 degrees, a 40 percent rating for extension limited to 30 degrees, and a 50 percent rating for extension limited to 45 degrees. See 38 C.F.R. § 4.71a, Diagnostic Code 5261. Under the version of diagnostic code applicable prior to February 7, 2021, a 10 percent rating is also available for slight recurrent subluxation or lateral instability of the knee, while a 20 percent rating is available for moderate recurrent subluxation or lateral instability, and a 30 percent rating for severe recurrent subluxation or lateral instability. 38 C.F.R. § 4.71a, Diagnostic Code 5257 (prior to February 7, 2021). As set forth in English v. Wilkie, 30 Vet. App. 347 (2018), objective evidence is not necessary to establish entitlement to a rating under diagnostic code 5257. Although the evaluation of the same disability under various diagnoses, known as pyramiding, is to be avoided, separate ratings are available for distinct symptoms that do not overlap. Pertinently, separate evaluations may be assigned for the same knee without violating the rules against pyramiding in 38 C.F.R. § 4.14. For instance, separate ratings are permissible for limitation of flexion and limitation of extension in the same knee. Notably, functional loss due to painful motion is to be rated to at least the minimum compensable rating for a particular joint. 38 C.F.R. § 4.59. As such, functional loss due to painful motion of the knee joint always warrants a 10 percent rating (that is, the minimum compensable rating). However, separate ratings are not available for painful extension and painful flexion without compensable limitation of motion. Additionally, the pre-February 7, 2021, version of diagnostic code 5010 stated that traumatic arthritis was to be rated as degenerative arthritis under diagnostic code 5003, which in turn provided that the severity of degenerative arthritis, when established by x-ray findings, would be rated on the basis of limitation of motion under the appropriate diagnostic codes for the joint or joints involved. When limitation of motion of the specific joint involved was noncompensable under the appropriate diagnostic codes, a 10 percent rating was available. However, a rating pursuant to diagnostic code 5010 could not be combined with a rating based on limitation of motion of the same joint. 38 C.F.R. § 4.71a, Diagnostic Code 5003. Effective February 7, 2021, these rating criteria have been amended, but, as set forth above, these amendments are not relevant to the Board's analysis here. Overview of Evidence Although the Board's focus is on evidence from up to one year prior to the receipt of the Veteran's claim for an increased rating, the Board has also reviewed the record as a whole to understand the history of the Veteran's left knee condition. The record reflects that, more than one year before his increased rating was received, he had complained of painful motion of his left knee. See, e.g., June 2001 VA Examination (noting "pain all the time" in the left knee and that he could walk but with pain). Evidence from the period up to one year prior to the receipt of his increased rating claim also indicates that the Veteran consistently complained of painful motion in his left knee. For instance, a December 2002 VA treatment record reflects that movement of the left knee was painful without swelling, while May 2003 VA treatment records also indicate that he had knee pain. In an October 2003 VA examination, the VA examiner noted decreased range of motion in the Veteran's left knee, with pain that he rated at a 7 out of 10. He also endorsed weakness, occasional swelling, stiffness, and "locking at times." He reported that he was using Lortab with flare-ups that would last up to 24 hours three times a week, particularly after walking for long periods or climbing stairs. He was using a left knee brace and felt like the knee "subluxes at times." He walked with a noticeable limp and with slight unsteadiness. Range of motion testing revealed motion from 0 to 110 degrees, with pain on flexion. Lachman's test and posterior cruciate ligament (PCL) testing were negative, but there was some slight laxity to the lateral joint line. In a September 2004 VA treatment records, the Veteran complained of left knee pain and swelling and popping. He reported that he treated this pain with NSAIDs, Lortab, muscle relaxants, and immobilization, but that he continued to have pain and swelling despite these treatments. He walked with a cane and had "reduced" range of motion in the left knee, although specific measurements were not reported. In an August 2006 treatment record, his range of motion was limited to 90 degrees of flexion. At a December 2007 VA examination, the Veteran reported that his left knee pain was constant and rated it a 9 out of 10. He also endorsed weakness, stiffness, swelling, instability, and fatigability, as well as locking in his left knee. Although he was using Tramadol, he reported that it had not decreased the severity of his symptoms. On range of motion testing, flexion was to 90 degrees and flexion was to -15 degrees. He also reported flare-ups that lasted up to 24 hours two to three times a week. Precipitating factors included climbing stairs or walking for extended periods of time, while an alleviating factor was rest. He estimated that he had additional limitation of motion of 10 to 25 percent during flare-ups. He used a left knee brace and cane and indicated that at times his knee would sublux. He walked with a noticeable limp and was unable to walk on his heels and toes due to unsteadiness. Stability testing was negative, although some testing could not be performed due to diminished range of motion in the knees. In a July 2009 VA treatment record, the Veteran endorsed knee pain and indicated that pain medications were ineffective. In a September 2009 VA treatment record, he stated that he could hardly stand up or walk and explained that he was in constant pain. In November 2009, he reported that he had pain constantly and during movement, which he rated as a 10 out of 10. He described the pain as shooting, stabbing, sharp, aching, burning, throbbing, and radiating, and exacerbated by movement, activities of daily living, and stress. He reported that nothing alleviated his pain, which affected general activities and other aspects of his life. In a November 2009 physical medicine rehabilitation consultation, however, he reported that relieving factors included medications, TENS and heat modalities. He had an abnormal but stable gait but walked with a cane and an elastic brace. His range of motion was limited with crepitus and pain. At a March 2010 VA examination, the Veteran reported that he was on Lortab for multiple complaints and that he could walk for two blocks. He was using a TENS unit and a cane. He endorsed constant sharp, burning, aching, throbbing pain in both knees. Additionally, he reported that he had flare-ups every day and that changes in the weather, walking, and running caused him to have more pain. He wore bilateral knee braces. His left knee was able to fully extend to 0 degrees and flex to 70 degrees, with no objective evidence of instability. At an October 2010 VA examination, he stated that he was unhappy with the outcome of the March 2010 VA examination. He reported that he had left knee pain, as well as weakness, stiffness, instability, locking up, a lack of endurance, and swelling. The pain was rated as an 8 but escalated to greater than a 10 at least three times a week and lasted all day. Flare-ups were precipitated by walking, stairs, prolonged drives, transferring, weather, and routine daily and job-related activities. He treated the pain with heat, ice, his knee brace, a TENS unit, elevation, and prescription medication. He was able to stand to for 30 minutes and walk 30 yards but stumbled and had falls. He used a knee brace and a cane to walk. At the examination, he presented with a slightly flexed posture and an antalgic gait. There was no objective evidence of instability after testing, but there was crepitus and grinding throughout range of motion testing. Flexion was to 95 degrees with pain throughout and extension was to 15 degrees with pain at 15 degrees. At the Veteran's January 2012 VA examination, he reported that he was taking various pain medications and that he could not walk more than a few yards. He was wearing knee braces and rated his pain at 10 out of 10. The pain was constant. On examination, left knee flexion was limited to 40 degrees with severe spasm noted, while extension was from 0 to 40 degrees, with severe spasm noted throughout. He could not do repetitive use testing due to pain. Instability and Subluxation As set forth above, the RO assigned a 20 percent rating under diagnostic code 5257 from January 1, 2001. The Board has carefully considered the subjective and objective evidence regarding instability and subluxation throughout the period on appeal. Nonetheless, the Board finds that a higher rating under this diagnostic code is not warranted during this timeframe. To that end, the October 2003 VA examination report reflects subjective complaints of occasional subluxation and locking at times, as well as objective evidence of slight unsteadiness when walking and some slight laxity to the lateral joint line. However, Lachman's test, PCL testing, and the bounce test were negative, and McMurray's test could not be performed. Similarly, at his December 2007 VA examination he reported instability and locking in the left knee, as well as subluxation. On examination, he walked with a noticeable limp and was unable to walk on his heels or toes due to unsteadiness. Stability testing, however, was negative. Likewise, July 2009 VA treatment records reflect an abnormal but stable gait, while his March 2010 VA examination report indicates no objective evidence of instability. The Veteran once more endorsed a history of instability and locking during his October 2010 VA examination, but there was no objective evidence of instability on physical examination. Last, the January 2012 VA examination report reflects that he used knee braces and had poor mobility but does not contain specific findings related to instability or subluxation. The Board has carefully considered the relevant evidence. Although the Veteran has repeatedly endorsed instability and locking, the objective medical evidence of record has been somewhat inconsistent with respect to whether instability and subluxation are present. The Board is also cognizant that the terms "slight," "moderate," and "severe" are not defined in the diagnostic code and that an examiner's use of these terms is not dispositive. As such, the Board has taken into account both the favorable objective evidence of slight instability and subluxation, as well as the subjective evidence of more severe instability and subluxation. Resolving all reasonable doubt in the Veteran's favor, the Board finds that a 20 percent rating is warranted for moderate symptoms under diagnostic code 5257 throughout the period on appeal, but no higher. Limitation of Extension The Board finds that a separate 10 percent rating is available from June 5, 2003, to December 17, 2007, for painful motion to a noncompensable degree under 38 C.F.R. § 4.59. To that end, the Board notes that the Veteran had reported painful motion with movement since more than a year prior to filing his claim for an increased rating. Although range of motion testing revealed decreased flexion at his October 2003 VA examination and in other VA treatment records, this flexion was not to a compensable degree. Even accounting for the ameliorative effects of pain medications that could have resulted in increased range of motion, the Veteran's range of motion would most likely not have been so limited that 10 percent ratings based on limitation of motion would have been warranted during this period. Beginning December 17, 2007, the Board finds that a 30 percent rating, but no higher, is warranted under diagnostic code 5010-5261 based on compensable limitation of extension. To that end, the record indicates that the Veteran had extension limited to 15 degrees on examination. As indicated in the examination report, he was taking pain medication at the time, but the pain medication had reportedly not decreased the severity of his symptoms. During flare-ups, however, he reported that his range of motion was reduced by another 10 to 25 percent. By the Board's calculations, this would mean that extension would be limited to approximately 20 degrees, which corresponds to a 30 percent rating under diagnostic code 5261. Although VA examination results from March 2010 and January 2012 indicate improved range of motion testing, results from another examination in October 2010 are consistent with the results from the December 2007 VA examination. Resolving reasonable doubt in the Veteran's favor, the Board will assume that the extension in his left knee consistent with the symptomatology associated with a 30 percent rating, similar to the limitation of extension displayed on the December 2007 VA examination. Affording him the benefit of the doubt, a 30 percent rating is warranted under diagnostic code 5261 for limitation of extension beginning on December 17, 2007. Even accounting for the effect of flare-ups, however, the evidence does not indicate that extension was limited to more than 20 degrees. As such, a rating in excess of 30 percent for limitation of extension is not available. Limitation of Flexion The Board has also considered whether a separate rating is available under diagnostic code 5010-5260 for limitation of flexion. Based on the evidence of record, however, a separate rating for limitation of flexion was not available until January 7, 2012. Prior to that point, flexion was not reduced to a compensable degree. For instance, the Veteran's October 2003 VA examination results reflect flexion to 110 degrees. Although pain was noted on flexion, it is unclear at what point this pain would begin. Additionally, the Veteran did not show compensable limitation of flexion during his December 2007 VA examination. The Veteran reported similar symptoms and information regarding flare-ups during both examinations. The Board will assume that range of motion testing during these examinations would not have been impacted by the use of pain medications, as the Veteran had told the December 2007 VA examiner that pain medications had not been able to decrease the severity of his symptoms. Nonetheless, the Board must also consider the impact of flare-ups on range of motion. However, even assuming that the Veteran's flexion was 10 to 25 percent more limited during flare-ups, his flexion would have been limited to approximately 80 degrees based on October 2003 VA examination results and 70 degrees based on December 2007 VA examination results. This degree of limitation of flexion still would not have been compensable. The same can be said for his March 2010 VA examination, which reflected flexion to 70 degrees, and the October 2010 VA examination, which reflected flexion to 95 degrees. Like at his previous VA examinations, the Veteran described the severity of his symptoms and his flare-ups in similar terms. Even accounting for a 10 to 25 percent reduction in range of motion testing on flexion during flare-ups, a separate rating based on compensable limitation of flexion would not have been available based on the results of his March 2010 and October 2010. However, the evidence suggests that a 20 percent rating is warranted for compensable limitation of flexion beginning January 7, 2012. In this regard, his January 2012 VA examination indicates that flexion was limited to 40 degrees on range of motion testing and that repetitive use testing could not be performed due to pain. Accounting for the additional limitation of motion caused by pain, as well as a 10 to 25 percent reduction in range of motion on flare-ups, the Board finds that these results are consistent with a 20 percent rating for limitation of flexion, but no higher. Additional Considerations As set forth above, 38 C.F.R. § 4.68 provides that the combined rating for disabilities of an extremity (in this case, the left knee) shall not exceed the rating for the amputation at the elective level if an amputation were to be performed. Here, this means that combined evaluations for disabilities of one knee cannot exceed 60 percent (i.e., the rating available under diagnostic code 5162 for an amputation at the knee). In this case, the Veteran's combined ratings for his left knee disability equal 60 percent beginning on January 7, 2012, based on his 20 percent rating under diagnostic code 5257, his 30 percent rating under diagnostic code 5010-5261, and his 20 percent rating under diagnostic code 5010-5260. As such, whether he is entitled to higher ratings for these disabilities after January 7, 2012, is not for consideration, as the maximum combined rating for the left knee has already been awarded from that point. For the period prior to January 7, 2012, the Board has considered whether separate ratings are warranted under other diagnostic codes, including diagnostic codes 5256 (ankylosis of the knee), 5258 (dislocated semilunar cartilage with frequent episodes of locking, pain, and effusion into the joint), 5259 (symptomatic removal of the semilunar cartilage), 5262 (impairment of the tibia and fibula), 5263 (genu recurvatum), and 5055 (knee replacement). With respect to diagnostic codes 5262, 5263, and 5055, these conditions are not present and thus separate ratings based on these diagnostic codes are not warranted. With respect to diagnostic code 5256, the Board notes that a minimum rating of 30 percent is available for ankylosis at a favorable angle in full extension or in slight flexion between 0 and 10 degrees. In this case, however, the evidence from this portion of the period on appeal does not reflect ankylosis or its functional equivalent. As such, a separate rating is not available under diagnostic code 5256. With respect to diagnostic codes 5258 and 5259, the Board notes that the evidence suggests either dislocated semilunar cartilage or symptomatic removal of the semilunar cartilage throughout the period on appeal. However, separate ratings under diagnostic codes 5258 and 5259 cannot be assigned in conjunction with ratings based on painful motion that have already been assigned. See Lyles v. Shulkin, 29 Vet. App. 107 (2017). Here, the Veteran was assigned a 10 percent rating under 38 C.F.R. § 4.59 for painful motion of the left knee from June 5, 2003, to December 17, 2007. As such, separate ratings under either diagnostic code 5258 or 5259 are unavailable during this timeframe. Additionally, beginning December 17, 2007, the Veteran is entitled to a 30 percent rating for limitation of extension. Pertinently, the Veteran's range of motion testing results from his December 2007 VA examination were commensurate with a rating lower than 30 percent, but the Board elevated the rating to 30 percent based in part on painful motion during flare-ups. As such, a separate rating under either diagnostic code 5258 or 5259 is unavailable throughout this portion of the appeal period, because the Veteran has already been assigned a rating based in part on painful motion. Furthermore, the Board has considered whether the VA examinations from October 2003, December 2007, March 2010, October 2010, and January 2012 comply with the holdings in Correia v. McDonald, 28 Vet. App. 158 (2016), and Sharp v. Shulkin, 29 Vet. App. 26 (2017). Pursuant to the holding in Correia, the final sentence of 38 C.F.R. § 4.59 requires that VA examinations include joint testing for pain on both active and passive motion, in weightbearing and non-weightbearing, and, if possible, with range of motion measurements of the opposite, undamaged joint. The holding in Sharp dictates that examiners must determine, where possible, the degree of additional range of motion that is lost due to pain on use or during flare-ups. If a veteran is not experiencing a flare-up during an examination, the examiner must instead elicit information from the veteran regarding the severity, frequency, duration, or functional loss manifestations of the flare-ups, or indicate whether such information could be gleaned from medical records or other sources available. Here, the evidence of record indicates that the Veteran's right knee joint is also damaged. Additionally, prior examiners have addressed pain in weight-bearing status and repetitive use testing (to the extent it could be performed). Although the examination reports do not contain separate findings on active and passive motion, the examiners indicated that the Veteran was able to move on his own free will, indicating that pain in active motion has been considered. It follows that an assessment of passive motion would yield the same result. With respect to flare-ups, it does not appear that any of the Veteran's VA examinations during the relevant timeframe were conducted during a flare-up of his left knee disabilities. Nonetheless, the Board notes that the October 2003, December 2007, March 2010, and October 2010 VA examiners took detailed notes regarding the Veteran's flare-ups, including their frequency, duration, severity, and precipitating and alleviating factors, as well as the functional limitations caused by such flare-ups. The Board acknowledges that none of the examiners except for the December 2007 VA examiner attempted to estimate the degree of loss of range of motion caused by flare-ups. However, the Veteran's descriptions of his flare-ups are highly similar in each of his VA examinations. As such, the Board finds that the December 2007 VA examination is adequate with respect to flare-ups, and that the information gleaned from this examination can be applied to other VA examinations in the record. Consequently, additional remand is not necessary to obtain additional information regarding flare-ups to satisfy the holding in Sharp. As such, although not all of the VA examiners solicited information to sufficiently describe the Veteran's flare-ups or their impact on his functional ability in terms of degrees of motion, the Board finds that the evidence was at least in relative equipoise to grant a higher rating for limitation of extension from December 17, 2007, and a separate rating for limitation of flexion from January 7, 2012, based on functional loss during flare-ups, beyond that reflected in available range of motion measures. See DeLuca v. Brown, 8 Vet. App. 202 (1995); see also 38 C.F.R. §§ 4.40, 4.45. Accordingly, the Board finds that VA's duty to assist with respect to obtaining VA examinations has been met. 38 C.F.R. § 3.159(c)(4); Sickels v. Shinseki, 643 F.3d 1362 (Fed. Cir. 2011). As a final matter, the Board has also considered whether referral of this matter for an extraschedular rating is appropriate. However, the Veteran has not contended, and the evidence does not reflect, that he has experienced symptoms outside of those contemplated by the rating criteria. In this regard, the Board is not obligated to analyze whether remand for referral for extraschedular consideration is warranted of 38 C.F.R. § 3.221(b)(1) is neither specifically sought by the claimant nor reasonably raised by the facts found by the Board. See Doucette v. Shulkin, 28 Vet. App. 366, 369-70 (2017) (quoting Dingess v. Nicholson, 19 Vet. App. 473, 499 (2006)). As such, referral for extraschedular consideration is not warranted. REASONS FOR REMAND 1. Left shoulder The Veteran contends that he has a current left shoulder disability stemming from a Humvee crash that occurred in the line of duty in 1989. For instance, he testified at his 2011 hearing that about two years after his accident, he got an MRI that showed that his rotator cuff had been torn for "a while" and that a doctor had told him it was probably related to his accident. He has also reported to various VA examiners and treatment providers that the pain in his left shoulder began following the Humvee crash. See, e.g., February 2021 VA Examination; September 2017 VA Examination; September 2012 VA Examination; March 2012 VA Treatment Record; January 2012 VA Examination. Most recently, the Board remanded this claim to obtain a new VA examination and opinion regarding the nature and etiology of the left shoulder disability. In February 2021, he reported to a VA examiner that he was in a motor vehicle accident in 1989. During the accident, his vehicle flipped and rolled over, causing him to lose consciousness. He reported that his shoulders were injured during this accident and that he has had shoulder pain since that time. The VA examiner, however, rendered a negative nexus opinion. In this regard, the VA examiner acknowledged that the Veteran was clearly in a motor vehicle accident in March 1989. However, the VA examiner also stated that his service treatment records were silent for left shoulder complaints and that a medical evaluation board summary from October 1989 did not discuss a shoulder injury, pain, or abnormalities. Confusingly, the VA examiner went on to state that a "labral tear could occur from a fall, particularly if the hand was outstretched," but also that the Veteran's shoulder condition was more likely a result of his shoulder anatomy, which "may predispose subacromial impingement." At this juncture, the Board finds that remand is warranted to obtain an addendum VA medical opinion regarding the etiology of the Veteran's left shoulder disability. To that end, the VA examiner's opinion does not adequately address the Veteran's lay statements regarding the onset of his shoulder condition, including his testimony that he received treatment shortly after service for shoulder pain. An opinion is inadequate if it does not consider all relevant evidence of record, including lay evidence. Nieves-Rodriguez v. Peake, 22 Vet. App. 295 (2008). Moreover, the VA examiner seemed to acknowledge that the Veteran could have been injured during his motor vehicle accident, but also that his shoulder anatomy may have predisposed him to subacromial impingement. These findings are couched in equivocal terms (e.g., "may," "could") and thus are entitled to little, if any, probative value. See Tirpak v. Derwinski, 2 Vet. App. 609, 611 (1992). In the interest of obtaining clear and reliable findings, the Board finds that remand is warranted to obtain a more definitive medical opinion. 2. Diabetes mellitus The Veteran has argued that he is entitled to service connection for diabetes mellitus because it is secondary to the treatments he is receiving for service-connected musculoskeletal disabilities and PTSD. To that end, he has argued that due to the medications that he takes, he has been told that his pancreas cannot produce the proper amount of insulin, which caused him to develop diabetes. Pursuant to the Board's most recent remand directives, the RO obtained a new VA medical opinion regarding the etiology of his diabetes in February 2021. The VA examiner stated that there was no evidence in the medical records to substantiate that the Veteran's diabetes mellitus was caused by medications taken for his service-connected knee or psychiatric disabilities. In the same opinion, however, the VA examiner stated that there were reports that typical anti-psychotic medications, such as quetiapine (which was in the Veteran's medication history) could cause hyperglycemia and diabetes, but that his diagnosis of diabetes preceded the quetiapine use. Moreover, he stated, without providing any explanation, that there was no good baseline measurement to state that diabetes had been aggravated by this medication. The Board finds that remand is necessary to obtain another addendum medical opinion with respect to diabetes. In this regard, an adequate medical opinion regarding secondary service connection must address causation and aggravation separately. See El Amin v. Shinseki, 26 Vet. App. 136, 140 (2013) (indicating that findings of "not due to," "not caused by," and "not related to" a service-connected disability are insufficient to address the question of aggravation under 38 C.F.R. § 3.310(b)). Here, however, the February 2021 VA examiner did not sufficiently address either causation or aggravation. To that end, the VA opined that there was "no evidence in the medical records" that his medications caused his diabetes to develop without citing any evidence to support this opinion. Moreover, he stated, without explaining why, diabetes had not been aggravated by his medications. An opinion that is conclusory or that does not provide a sufficiently detailed rationale is inadequate. Stefl v. Nicholson, 23 Vet. App. 320 (2007). As such, remand is warranted to obtain another medical opinion regarding the etiology of his diabetes. Accordingly, the matters are REMANDED for the following action: Obtain supplemental medical opinions from an appropriate clinician(s) regarding the nature and etiology of the Veteran's left shoulder disability and diabetes mellitus. The examiner(s) must review the entire claims file, including a copy of this Remand, and acknowledge such review in the examination reports. After reviewing the claims file in its entirety, the examiner(s) is asked to do the following: (a.) With respect to the left shoulder disability, opine as to whether it is at least as likely as not (approximately 50 percent or greater probability) that the Veteran's left shoulder disability had its onset during, or is otherwise related to, his military service, to include a 1989 motor vehicle accident. (b.) With respect to diabetes mellitus, opine as to whether it is at least as likely as not (approximately 50 percent or greater probability) that the Veteran's diabetes mellitus was (1) caused, or (2) aggravated by a service-connected musculoskeletal disability or PTSD, including the medications used to treat these disabilities. The examiner is reminded that "causation" and "aggravation" are distinct legal concepts that must be separately addressed. A sufficiently detailed rationale for any opinion offered should be provided, citing to supporting clinical data, medical literature, and other evidence from the record. In doing so, the examiner is reminded to consider all relevant evidence, such as the Veteran's service treatment records, which indicate he was in a motor vehicle accident in 1989, as well as his VA treatment records, 2011 hearing testimony, and other lay statements made throughout the record. M. Tenner Veterans Law Judge Board of Veterans' Appeals Attorney for the Board E. Rademacher, Associate 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.