Citation Nr: 0203188 Decision Date: 04/08/02 Archive Date: 04/18/02 DOCKET NO. 99-16 695 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Detroit, Michigan THE ISSUES 1. Entitlement to service connection for shortening of the right leg. 2. Entitlement to service connection for a low back disorder, claimed as secondary to the shortening of the right leg. REPRESENTATION Appellant represented by: Disabled American Veterans WITNESS AT HEARINGS ON APPEAL Veteran ATTORNEY FOR THE BOARD N. W. Fabian, Counsel INTRODUCTION The veteran reportedly had active duty from October 1985 to February 1990 which has not been verified. These matters come to the Board of Veterans' Appeals (Board) from the timely appeal of a March 1999 rating decision of the Department of Veterans Affairs (VA) Regional Office (RO) at Detroit, in which the RO denied entitlement to service connection for shortening of the right leg and a low back disorder secondary to the leg shortening. FINDINGS OF FACT 1. The RO has notified the veteran of the evidence needed to substantiate his claim, obtained all relevant evidence designated by the veteran, provided him VA medical examinations, and an independent medical opinion has been obtained in order to assist him in substantiating his claim for VA compensation benefits. 2. The defect in the right lower extremity resulting in a leg length discrepancy existed prior to the veteran entering active service, and is not shown to have been aggravated by active service. 3. A chronic low back disorder was not shown during service, and is not shown to be related to an in-service disease or injury or a service-connected disorder. CONCLUSIONS OF LAW 1. Shortening of the right leg was not incurred in or aggravated by active service. 38 U.S.C.A. §§ 1111, 1131, 1137, 1153, 5107 (West 1991 & Supp. 2001); 38 C.F.R. §§ 3.303, 3.304, 3.306 (2001). 2. A low back disorder was not incurred in or aggravated by active service, and is not due to or the proximate result of a service-connected disability. 38 U.S.C.A. §§ 1131, 5107 (West 1991 & Supp. 2001); 38 C.F.R. §§ 3.303, 3.310 (2001). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS Factual Background Medical records from the Northern Michigan Hospital show that prior to entering service the veteran was examined and treated for congenital shortening and bowing of the right tibia. An X-ray study of both hips, both legs, and the right ankle for that stated purpose in August 1980 revealed an abnormality at the junction of the middle and distal thirds of the right tibia. The abnormality measured 2.7 by 2.5 by 1.5 centimeters in size. In September 1980 the veteran underwent the surgical removal of what was determined to be a bone cyst, resulting in the removal of a piece of bone that was three-eighths inch by three-eighths inch in size from the lateral aspect of the tibia. The contents of the cyst were removed from the cavity of the tibia, and the bone was then filled with bone chips. A December 1980 treatment record from the Burns Clinic Medical Center indicates that the veteran complained of problems with his right knee, which his physician assessed as tendonitis. He was doing some cross-country skiing, but had not yet returned to full activity. The treating physician recommended that the veteran perform exercises to stretch his hamstrings. An X-ray study then revealed that the lesion resulting from the surgery was about healed, and the veteran was released to resume full activity. An additional X-ray study was conducted in April 1981 due to a leg length discrepancy. The report of the X-ray study indicates that the leg length discrepancy on the right had been slightly over-corrected, with the right iliac crest being seven millimeters higher that the left. Measuring the lower extremities from the tip of the medial malleolus to the extreme upper cortex of the femoral heads showed the left leg to be four millimeters shorter than the right. An August 1983 summary from Good Samaritan Hospital shows that the veteran complained of severe left flank pain, which was initially attributed to renal colic. He was discharged from the hospital with diagnoses of hematuria, prostatitis, and back pain, cause undetermined. He was again hospitalized in November 1983 and June 1984 for renal colic. The service medical records indicate that on entering active duty the veteran reported having or having had swollen or painful joints, broken bones, and a cyst. In explaining those complaints the examining physician found that the veteran had Osgood-Schlatter's disease in the left knee, and that he had undergone the excision of a benign cyst from the lower left leg with a bone graft. On examination the physician documented full range of motion in both knees, and a scar on the right leg. An X-ray study of the lower right leg was requested in conjunction with the examination, but if it was performed a report of the study is not of record. In February 1986 the veteran complained of a throbbing pain in the lower right leg of two months in duration. The pain normally occurred after running or prolonged standing. Examination revealed tenderness to palpation in the right lower extremity, and his complaints were attributed to shin splints. He again complained in April 1986 of right lower leg pain, progressively worse since December 1985. He then reported having had surgery for a benign tumor in October 1980. A current X-ray study showed evidence of an old bony density and the prior surgery, but no acute changes. On evaluation by an orthopedist the pain was attributed to a questionable stress reaction. The veteran reported having pain, clicking, and giving way of the right knee in March 1987, and having had a tumor removed from the tibia in 1980. Examination then showed a one-fourth inch shortening of the right lower leg, and a 30 degree external rotation deformity of the right tibia and fibula. An arthrogram of the right knee was negative, and the symptoms were attributed to probable symptomatic mal- alignment of the lower leg with external rotation and a varus bow. Medication did not sufficiently alleviate the symptoms, and surgery was performed in May 1987. The records pertaining to the May 1987 surgery indicate that the veteran's history was pertinent for a prior curettage and bone graft of the distal right tibia due to a bone cyst, with resulting 60 degree external mal-rotation of the right lower leg in comparison to the orientation of the right knee, one- half inch shortening of the right lower leg, and medial right knee pain secondary to the deformity. Surgical correction of the deformity was performed, with a rotational osteotomy of the right tibia with fixation. According to the operative report, a transverse osteotomy was performed one centimeter distal to the post-operative changes to the tibia. The fibula was also incised. The external rotation deformity was corrected by rotating the distal fragment of the tibia, and the incision fixed with a steel plate. There were no complications from the surgery, and the post-surgical course was uneventful. The right lower extremity was placed in a short leg walking cast until October 1987. Multiple X-ray studies following the surgery showed the right tibia and fibula to be in good alignment and that the osteotomy was well healed. In September 1987 the veteran complained of increasing pain in the right leg, and was then walking with a cane and a slight limp. Examination revealed the wound to be well healed, and the alignment to be excellent. The physician then determined that the osteotomy needed additional time to heal. The veteran was still limping in December 1987, and examination then showed the leg lengths to be equal. The physician prescribed physical therapy, to include gait training, but the veteran did not appear for the appointments. The veteran did well until March 1988, when he sustained a contusion to the right leg at the site of the surgery in a fall off an embankment, and was then walking with a marked limp. He complained of pain in the right lower leg, which was attributed to bursitis resulting from the fixation screw. Surgery was performed to remove the screws and plate from the right tibia. Examination in May, August, and November 1988 disclosed the operation site to be well healed, and the veteran was asymptomatic in November 1988. Following the surgery he was given a limited profile through November 1988. The veteran injured his right knee in May 1989 when riding a motorcycle, with pain and locking of the knee. An X-ray study showed no abnormalities, and his symptoms were assessed as traumatic right patellofemoral pain. He was given exercises to perform and an additional limited profile. The right knee symptoms were found to be resolving in July 1989. In conjunction with his January 1990 separation examination the veteran again reported having or having had swollen or painful joints, broken bones, and a cyst. In commenting on those complaints the examiner indicated that the veteran had a history of post-surgical degenerative joint disease in the right knee, but physical examination revealed no abnormalities in the right lower extremity other than the surgical scars. The veteran submitted the report of a June 1987 X-ray study of the right tibia and fibula, which was conducted while he was on convalescent leave following the leg surgery. In comparison to the December 1980 study, the June 1987 X-ray study disclosed a recent interval osteotomy of the distal fibular and tibial diaphyses. A plate and six screws secured the tibial osteotomy, and the tibia and fibula were in anatomic alignment. The non-ossifying fibroma of the distal tibia had been removed. In an April 1996 report Joseph M. McGraw, M.D., stated that the veteran then complained of right leg pain, and reported a six-month history of low back and right hip pain. He also had a history of a tibial rotation osteotomy, and attributed a leg length discrepancy to the osteotomy. He had previously been given a lift to wear in his right shoe, but had not used it recently. On examination he walked with a short leg gait on the right. There was a 2.5 centimeter leg length discrepancy, right shorter than left. Dr. McGraw attributed the veteran's complaints to probable sacroiliitis, and stated that the leg length discrepancy was more than likely exacerbating his back complaints. A whole-body bone scan in April 1996 disclosed a single focus of abnormal activity in the proximal left fibula, but no other abnormalities. An April 1996 private treatment record from an unknown provider indicates that the veteran reported having had five surgeries on his right leg, resulting in shortening of the right leg. He complained of mid-back pain, and reported having injured his back in a fall several years previously. He asserted that his back problems were made worse by a chiropractor two years previously. Examination revealed moderate spasm in the mid-dorsum area. Examination four days later showed a significant (greater than one inch) shortening of the right leg. The veteran complained of low back and right hip pain in December 1996 after having lifted a snowmobile. In March 1997 he reported that his back pain was worse. The veteran initially claimed entitlement to compensation benefits in November 1998, at which time he asserted that the shortening of the right leg was caused by the in-service surgery, and that his low back and right hip problems were due to the shortening of the right leg. In conjunction with a March 1999 VA examination, the veteran again said that the one inch shortening of the right leg was due to the in-service osteotomy. He started having pain in the low back and right hip in 1996, with shortening of the right leg. The examiner found that the right leg was one inch shorter than the left, and that the veteran walked with a limp on the right when not using a shoe lift. Examination of the low back and right hip, including X-ray studies, showed no abnormalities. The examiner assessed the complaints and findings as lower back pain and right hip pain as secondary to ligamentous strain. The examiner found that the ligamentous strain was due to the in-service surgery, which resulted in shortening of the right leg. In an April 1999 statement, his June 1999 notice of disagreement, and his July 1999 substantive appeal, the veteran reported that following the osteotomy in service his right knee pain went away. He started to have hip and back pain in 1995, at which time he found out that his right leg was one inch shorter than the left. He asserted that the shortening of his right leg was caused by the surgery in service. He attributed his back and hip pain to not having been given a shoe lift following the in-service surgery. The RO provided the veteran an additional VA examination in September 1999. He again complained of right lower back and right hip pain. He reported having had a bone cyst removed from the right tibia at the age of 14 years, following which he had no problems and played sports in school. He developed pain in the right knee after having been in service a couple of years, when he was advised of a deformity in the right leg. He had an osteotomy performed in 1987, after which his right leg was casted for 18-19 months. In 1995 he again experienced pain in the right leg, when he was notified of the shortening of the right leg. Examination revealed a five-eighths inch shortening of the right leg with shortening of the femoral bone, but not the tibia. There was also a varus deformity of the right leg. An X-ray study of the right leg disclosed the healed osteotomy of the distal tibia, which was in normal alignment, and no abnormalities pertaining to the right knee. The long X-ray film for leg length measurement showed moderate pelvic tilt, with the right femur being two centimeters shorter than the left, resulting in a two-centimeter shortening of the right leg. The examiner provided diagnoses of chronic low back and right hip pain, with no objective evidence of orthopedic pathology, and five-eighths inch shortening of the right femoral bone. Based on review of the evidence in the claims file, the examiner found that the shortening of the right lower extremity was due to a developmental defect that pre-existed service, that the in-service corrective surgery did not result in any residual disability or cause any ambulatory symptoms, and concluded that the pre-existing developmental abnormality had not been aggravated during service. The examiner also found that the shortening of the right lower extremity was due to shortening of the femur and not the tibia, where the surgery had been performed. The examiner further found that the bone graft site in the right iliac crest did not result in any ambulatory symptoms. The veteran presented testimony at a hearing before an RO Hearing Officer in January 2000. He denied having had any problems with his right leg between the surgery in 1980 and his entrance on active duty, or any problems during basic training. He denied that the in-service surgery alleviated any of the pain he was having in the right knee. He was having pain in his low back and right hip in 1996, when the shortening of the right leg was initially found. He was then prescribed shoe lifts to alleviate his limp. He stated that he had walked with a limp on the right leg since the in- service surgery, which he had previously attributed to having worn a cast for so long, but that he did not develop any pain in the leg, hip, or back until four years later. He denied having any limp when he entered service, because it would have been found during his entrance examination or during basic training. The veteran presented the report of an April 2000 computerized tomography (CT) scan of the right lower extremity that was conducted to investigate a leg length discrepancy. That study showed the length of the left femur to be 47.9 centimeters in length, while the right femur was 47.2 centimeters in length. The left tibia was 36.8 centimeters, and the right tibia was 36.2 centimeters. The overall length of the left lower extremity was 84.7 centimeters, compared to 83.4 centimeters on the right, resulting in the right lower extremity being 1.3 centimeters shorter than the left. The veteran also presented testimony before the undersigned in November 2000. In addition to the information previously provided, he stated that he did not have an abnormal gait while in basic training because it would have been discovered by his drill instructor. He denied having had any surgical procedures performed on the right femur, or thigh bone. In view of the conflicting evidence concerning whether the veteran's leg length discrepancy was aggravated by service, the Board requested an independent medical opinion. In an August 2001 report Richard M. Terek, M.D., an orthopedic surgeon, stated that he had reviewed the veteran's claims file, in which the August 1980 X-ray request documented that the veteran had a congenital shortening and bowing of the right tibia prior to entering service. He also referenced the April 1981 X-ray study that showed that the leg length discrepancy had been over-corrected, again indicating that a leg length discrepancy existed prior to the veteran entering service. The hospital summary pertaining to the in-service osteotomy showed that the veteran's right leg was one-half inch shorter than the left prior to the surgery. That degree of shortening was also reflected in the April 2000 CT scan because the 1.3 centimeters shown in the CT scan was approximately the same as one-half inch. Six millimeters of that discrepancy was due to shortening of the right tibia, and the remainder was due to shortening of the femur. Dr. Terek noted that although the April 1981 X-ray study disclosed that the right lower extremity was four millimeters shorter than the left, the evidence did not indicate whether the veteran had then reached skeletal maturity (he was then almost 16 years of age). He found that the osteotomy performed in service would not have resulted in significant shortening of the leg, in that the only shortening that would occur was due to the width of the saw blade. He described that shortening as trivial, and stated that it would not contribute significantly to the pre-existing leg length discrepancy. He found, with a reasonable degree of medical certainty, that it is not at least as likely that the veteran's current leg length discrepancy is due to the corrective orthopedic surgery performed while he was in service or was otherwise related to service. In response to Dr. Terek's opinion, the veteran's representative provided a medical opinion from Craig N. Bash, M.D., a neuroradiologist. Dr. Bash also reviewed the claims file, and determined that the veteran had entered service with the right leg being one-fourth inch shorter than the left, as shown in the March 1987 service medical records. Measurements taken before the May 1987 osteotomy showed the right leg to be one-fourth to one-half inch shorter than the left. Measurements taken after his separation from service showed the right leg to be 1.3 centimeters to one inch shorter than the left. Based on that evidence Dr. Bash stated that, to a reasonable degree of medical certainty, the veteran acquired additional shortening of the right leg during service. He also stated that the leg length discrepancy caused the veteran's current right knee, right hip, and back problems due to an abnormal gait. Duty to Assist The regulation pertaining to VA's duty to inform the veteran of the evidence needed to substantiate his claim and to assist him in developing the relevant evidence was recently revised. Duty to Assist, 66 Fed. Reg. 45,620 (Aug. 29, 2001) (to be codified at 38 C.F.R. § 3.159). The changes in the regulation are effective November 9, 2000, with the enactment of the Veterans Claims Assistance Act of 2000 (VCAA), Pub. L. No. 106-475, 114 Stat. 2096 (2000), and apply to all claims filed on or after November 9, 2000, or filed previously but not yet final as of that date. Holliday v. Principi, 14 Vet. App. 282-83 (2001), mot. for recons. denied, 14 Vet. App. 327 (2001) (per curiam), motion for review en banc denied, No. 99-1788 (U.S. Vet. App. May 24, 2001) (per curiam) (en banc); VAOPGCPREC 11-00. Because the veteran had appealed the March 1999 denial of service connection, that decision was not final on November 9, 2000, and the provisions of the VCAA apply to his claim. According to the revised regulation, on receipt of a claim for benefits VA will notify the veteran of the evidence that is necessary to substantiate the claim. VA will also inform the veteran which information and evidence, if any, he is to provide and which information and evidence, if any, VA will attempt to obtain on his behalf. VA will also request that the veteran provide any evidence in his possession that pertains to the claim. VA will also make reasonable efforts to help the veteran obtain evidence necessary to substantiate the claim, including making efforts to obtain his service medical records, if relevant to the claim; other relevant records pertaining to service; VA medical records; and any other relevant records held by any Federal department or agency, State or local government, private medical care provider, current or former employer, or other non-Federal governmental source. In a claim for disability compensation, VA will provide a medical examination which includes a review of the evidence of record if VA determines it is necessary to decide the claim. Duty to Assist, 66 Fed. Reg. 45,630 (Aug. 29, 2001) (to be codified at 38 C.F.R. § 3.159). In this case, the RO informed the veteran of the evidence needed to substantiate his claim in March 1999, February 2000, and March 2000. The RO provided the veteran a statement of the case and supplemental statements of the case in July 1999, October 1999, February 2000, April 2000, and May 2000. In those documents the RO informed the veteran of the regulatory requirements for establishing service connection, and provided him the rationale for not awarding service connection. The veteran's representative has been provided the claims file for review on multiple occasions, and submitted additional evidence in support of the appeal with a waiver of consideration of that evidence by the RO in the first instance. 38 C.F.R. § 20.1304. The RO notified the veteran that his case was being sent to the Board, and informed him that any additional evidence that he had should be submitted to the Board. The Board finds, therefore, that VA has fulfilled its obligation to inform the veteran of the evidence needed to substantiate his claim. The RO has obtained the veteran's service medical records and the relevant private treatment records designated by the veteran, and provided him VA examinations in March 1999 and September 1999. The veteran presented testimony before the RO Hearing Officer in January 2000, and before the undersigned in November 2000. The Board has obtained an independent medical opinion to assist the veteran in substantiating his claim for compensation benefits. The veteran has not indicated the existence of any other evidence that is relevant to his appeal. The Board concludes that all relevant information has been obtained for determining the merits of the veteran's claim and that VA has fulfilled its obligation to assist him in substantiating his claim for VA benefits. Laws and Regulations Service connection may be established for a disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C.A. § 1131. For the showing of chronic disease in service there is required a combination of manifestations sufficient to identify the disease entity, and sufficient observation to establish chronicity at the time. If chronicity in service is not established, a showing of continuity of symptoms after discharge is required to support the claim. Service connection may be granted for any disease diagnosed after discharge, when all of the evidence establishes that the disease was incurred in service. 38 C.F.R. § 3.303. Service connection may also be granted for a disability which is proximately due to or the result of a service connected disease or injury. 38 C.F.R. § 3.310(a). In order to establish service connection for the claimed disorder, there must be (1) medical evidence of a current disability; (2) medical, or in certain circumstances, lay evidence of in-service incurrence or aggravation of a disease or injury; and (3) medical evidence of a nexus between the claimed in-service disease or injury and the current disability. Hickson v. West, 12 Vet. App. 247, 253 (1999). A veteran is presumed to have been in sound condition when enrolled for service, except for any disease or injury noted at the time of enrollment. Only such conditions as are recorded in examination reports are to be considered as noted. The veteran's reported history of the pre-service existence of a disease or injury does not constitute notation of such disease or injury, but is considered with all other evidence in determining if the disease or injury pre-existed service. The presumption of soundness can be rebutted if clear and unmistakable evidence demonstrates that the disease or injury existed prior to enrollment and was not aggravated by such service. 38 U.S.C.A. §§ 1111, 1137; 38 C.F.R. § 3.304(b). A pre-existing injury or disease will be considered to have been aggravated by active service where there is an increase in disability during such service, unless clear and unmistakable evidence shows that the increase in disability is due to the natural progress of the disease. 38 U.S.C.A. § 1153; 38 C.F.R. § 3.306. For compensation purposes, the term "aggravation" has specific meaning, based on the controlling statute and regulation and judicial interpretation of the relevant law. A pre-existing disease or injury will be presumed to have been aggravated by service only if the evidence shows that the underlying disability underwent an increase in severity. Townsend v. Derwinski, 1 Vet. App. 408 (1991); 38 C.F.R. § 3.306(a). A flare-up of symptoms, in the absence of an increase in the underlying severity, does not constitute aggravation of the disability. Hunt v. Derwinski, 1 Vet. App. 292, 296-97 (1991). Evidence of the veteran being asymptomatic on entry into service, with an exacerbation of symptoms during service, does not constitute evidence of aggravation. Green v. Derwinski, 1 Vet. App. 320, 323 (1991). If the disorder becomes worse during service and then improves due to in-service treatment to the point that it was no more disabling than it was at entrance into service, the disorder is not presumed to have been aggravated by service. Verdon v. Brown, 8 Vet. App. 529 (1996). The determination as to whether the requirements for service connection are met is based on an analysis of all the evidence of record and the evaluation of its credibility and probative value. Baldwin v. West, 13 Vet. App. 1 (1999); 38 C.F.R. § 3.303(a). Once the evidence is assembled, the Board is responsible for determining whether the preponderance of the evidence is against the claim. If so, the claim is denied; if the evidence is in support of the claim or is in equal balance, the claim is allowed. 38 U.S.C.A. § 5107 (West Supp. 2001); Ortiz v. Principi, 274 F.3d 1361, 1365-66 (Fed. Cir. 2001); 38 C.F.R. § 3.102 (as amended by 66 Fed. Reg. 45,620 (Aug. 29, 2001)). Analysis The medical evidence indicates that the veteran's right leg is 1.3 centimeters to one inch shorter than his left leg. His claim for service connection is, therefore, supported by medical evidence of a current diagnosis of disability. For the reasons that will be explained below, however, the Board finds that the defect of the right lower extremity existed prior to the veteran's entry on active duty and was not aggravated during service. His claim is not, therefore, supported by probative evidence of in-service aggravation of a disease or injury, or medical evidence of a nexus between the aggravation of a disease or injury and the current disability. Hickson, 12 Vet. App. at 253. Although the veteran reported on entering service that he had undergone the excision of a benign cyst from the lower [left] leg prior to service, no abnormalities pertaining to the lower extremities were noted as the result of the physical examination. The veteran is, therefore, entitled to the presumption of soundness on entering service. The pre- service medical records show, however, that he underwent surgery for a defect in the right leg, specifically congenital shortening and bowing of the right tibia, in 1980. A one-third to one-half inch shortening of the right lower extremity was found prior to the May 1987 osteotomy, and the physician providing the treatment determined that the shortening and mal-alignment of the right leg was caused by the pre-service surgery. Although the examiner in March 1999 found that the shortening of the right leg resulted from the in-service surgery, that assessment was based on the veteran's report of having undergone the osteotomy in May 1987, without any reference to the pre-existing abnormality or surgical treatment. The finding is not, therefore, probative of whether the disorder pre-existed service. See Godfrey v. Brown, 8 Vet. App. 113, 121 (1995) (an opinion that is based on the veteran's reported history is not probative). The examiner in September 1999 determined that the defect in the right lower extremity was developmental, in that it affected the femur that was not altered by the osteotomy, as well as the tibia. Dr. Terek also found that the veteran had a congenital defect in the right lower extremity that pre-existed his entry into service. Although Dr. Terek incorrectly referenced the April 1981 X-ray study as showing that the right leg was four millimeters shorter than the left, he also noted that that X- ray study indicated that the previous shortening of the right leg had been over-corrected. He relied on the X-ray study as evidence of a leg length discrepancy, and not a specific finding that the right leg was then shorter than the left. He also noted that the leg length discrepancy shown in April 1981 did not reflect whether the veteran had reached skeletal maturity, or was still growing. In addition, Dr. Bash acknowledged that a leg length discrepancy pre-existed the veteran's entry on active duty. He found that it was clear from review of the medical evidence that the veteran entered service with a leg length discrepancy, as shown in the medical records pre-dating the May 1987 osteotomy. In determining whether a disorder pre-existed service all medically accepted evidence can be considered, and the determination is not limited to contemporaneous evidence documenting the existence of the disorder. Harris v. West, 11 Vet. App. 456 (1998), aff'd 203 F.3d 1347 (Fed. Cir. 2000). The veteran has denied having a leg length discrepancy from August 1980 until he entered service. As a lay person the veteran is competent to provide evidence of observable symptoms, but he is not competent to provide evidence that requires specialized medical knowledge or diagnostic skills, such as determining a leg length discrepancy. Espiritu v. Derwinski, 2 Vet. App. 492, 494 (1992). He also testified that he was not aware that he had a leg length discrepancy until he sought treatment for back pain in 1995. The Board finds, therefore, that his assertions are not probative of whether the lower extremity defect pre-existed service. Although the April 1981 X-ray study indicates that the right leg was then four millimeters longer than the left, that finding was made more than four years prior to when the veteran entered service, did not indicate whether he had reached skeletal maturity, and does not refute the finding that he had a defect in the right lower extremity prior to entering service that affected the length of the lower extremity. The Board finds, therefore, that the April 1981 X-ray study is not probative of whether there was a congenital or developmental defect in the veteran's right lower extremity prior to entering service. See Vanerson v. West, 12 Vet. App. 254 (1999) (evidence indicating that a disorder did not pre-exist service does not preclude a finding that it did, if the contrary evidence is not probative). For these reasons the Board finds that clear and unmistakable evidence demonstrates that the defect in the right lower extremity resulting in a leg length discrepancy existed prior to the veteran's entry on active duty, and that the presumption of soundness has been successfully rebutted. 38 C.F.R. § 3.304(b). The essential question remains as to whether the shortening of the right leg underwent an increase in severity during service, due to the May 1987 surgery or any other disease or injury. The veteran began experiencing symptoms in the right lower leg in December 1985, about five months after he entered service. Examination in March 1987 showed one-fourth inch shortening of the right lower extremity, in comparison to the left, and examination in May 1987 disclosed one-half inch shortening. The right leg was, therefore, shorter than the left prior to any surgery being performed on the leg during service. Examination in December 1987 showed the leg lengths to be equal, and no abnormalities were found on examination when the veteran separated from service. There is no further documentation of the comparable lengths of the lower extremities until April 1996, six years after the veteran separated from service, at which time Dr. McGraw determined that the right leg was 2.5 centimeters, or one inch, shorter than the left. The veteran did not report having any symptoms attributable to a leg length discrepancy, including pain in the leg, back, or hip, until 1995. Although Dr. McGraw documented the shortening of the right leg, he did not provide any cause or etiology for the abnormality. The examiner in March 1999 found that the shortening of the right leg was due to the in-service surgery, but that opinion was based on the veteran's report that the right leg was one inch shorter than the left following the surgery, and without consideration of the pre- service medical records. As previously stated that opinion, which was based on the veteran's reported history and not supported by the contemporaneous evidence, is of no probative value in finding whether the pre-existing disorder was aggravated during service. Godfrey, 8 Vet. App. at 121. The examiner in September 1999 found that the leg length discrepancy had not been aggravated during service, because the shortening of the right leg documented in September 1999 X-rays showed the shortening to be in the femur, not the lower leg where the osteotomy was performed. The examiner also found that the in-service surgery had not resulted in any residual disability. Because that opinion was based on review of the evidence in the claims file, and not the veteran's reported history, it is highly probative. Owens v. Brown, 7 Vet. App. 429, 433 (1995). Based on review of the evidence in the claims file, Dr. Terek found that the in-service rotational re-alignment of the tibia and fibula could not have resulted in any additional shortening of the right leg, other than the trivial amount due to the thickness of the saw blade used to cut the bone. He also noted that the April 2000 CT scan reflected the same leg length discrepancy found prior to the surgery in May 1987, that being one-half inch or 1.3 centimeters. Because that opinion was provided by an orthopedic surgeon, was based on review of the medical evidence of record, and was supported by logical reasoning, it is highly probative. Dr. Bash found that the pre-existing leg length discrepancy was aggravated by service. He based that opinion, however, on the conclusion that the veteran had entered service with one-fourth inch shortening of the right leg, and that while in service he developed a limp, degenerative joint disease of the right knee, and right knee pain. Although the veteran demonstrated a limp following the May 1987 surgery, no gait abnormalities were documented after the hardware was removed from the leg in March 1988. The veteran testified that he had a limp since the May 1987 surgery, but that assertion is not supported by the contemporaneous records, which show no abnormalities after March 1988. In addition, evidence of the veteran having been asymptomatic on entering service, and later developing symptoms of the pre-existing disorder, does not constitute aggravation in the absence of evidence of an increase in the underlying disorder. Davis v. Principi, 276 F.3d 1341, 1345 (Fed. Cir. 2002). The reference to degenerative joint disease of the right knee during the separation examination was apparently based on the veteran's subjective complaint, in that the X-ray study in May 1989 did not show any degenerative changes in the right knee. No additional X-rays were conducted during the separation examination. The examiner in September 1999 expressly found no evidence of arthritis in the knee, and none of the remaining medical records documents such a finding. The right knee pain that the veteran experienced in service was alleviated by the May 1987 surgery, based on his own report, and cannot be considered in finding whether the pre-existing disorder was aggravated during service. Verdon, 8 Vet. App. at 529. Dr. Bash also based his opinion on the finding that prior to the May 1987 osteotomy the right leg was one-fourth to one- half inch shorter than the left, but that in April 1996 the right leg was found to be one-half inch (1.3 centimeters) to one inch shorter. Although he stated that "to a reasonable degree of medical certainty" the increase in the leg length discrepancy occurred during service, he did not (1) provide any medical analysis of the surgical procedures performed during service; (2) account for the difference in the lengths of the femurs, which were not operated on in service; (3) consider whether the veteran had reached mature skeletal growth when he entered service; (4) account for the absence of any leg length discrepancy in December 1987; (5) articulate any reason why the increase occurred during rather than after service; or otherwise provide any rationale for his conclusion. In addition, it is not clear what medical expertise a specialist in neuroradiology would have in assessing the affect of a skeletal surgical procedure, in that neuroradiology pertains to diagnostic radiology of diseases of the nervous system. Stedman's Medical Dictionary 1205 (26th Ed.). The Board finds, therefore, that Dr. Bash's opinion is of low probative value in determining whether the defect in the right lower extremity was aggravated during service. Hernandez-Toyens v. West, 11 Vet. App. 379, 382 (1998) (the failure of the physician to provide a basis for his or her opinion goes to the weight or credibility of the evidence). Dr. Bash found Dr. Terek's opinion deficient because Dr. Terek did not address the limp that the veteran demonstrated in service. As previously stated, no abnormalities were shown following the March 1988 removal of the hardware, and the development of symptoms does not constitute aggravation. Davis, 276 F.3d at 1345. He also interpreted Dr. Terek's reference to a "trivial" increase in the shortening of the leg as referring to the 2.5 centimeter discrepancy shown in April 1996, or the 1.3 centimeter discrepancy shown in April 2000. Dr. Terek was not referring to the additional shortening of the leg documented after the veteran's separation from service; Dr. Terek described as "trivial" any shortening of the bone due to the osteotomy, which was limited to the width of the bone saw. Dr. Bash also relied on the veteran having had documented back pain during service. In summarizing the evidence, however, the only documented back pain referenced by Dr. Bash occurred in 1984, prior to the veteran's entry on active duty. The Board finds no contemporaneous evidence of any complaints or clinical findings pertaining to a low back disorder during service. The veteran has claimed entitlement to service connection for the low back as secondary to the shortening of the right leg. Dr. Terek was not required to provide an opinion on the etiology of the low back complaints documented in 1996, because he did not find that shortening of the right leg had been aggravated by service. For the reasons discussed, the Board finds that the opinions of the examiner in September 1999 and Dr. Terek are more probative than the opinions of the examiner in March 1999 and Dr. Bash, and that there was no increase in the underlying defect resulting in shortening of the right leg during active service. See Wensch v. Principi, 15 Vet. App. 362, 368 (2001) (it is not error for the Board to favor the opinion of one competent medical expert over that of another when the Board gives an adequate statement of reasons and bases for doing so). The presumption of aggravation does not, therefore, apply. Because the defect resulting in shortening of the right leg was not aggravated during service, the preponderance of the evidence is against the claim of entitlement to service connection for shortening of the right leg. The veteran has also claimed entitlement to service connection for a low back disorder. As previously stated, the service medical records are silent for any complaints or clinical findings related to a back disorder, and the veteran does not claim otherwise. He asserts that his low back symptoms are secondary to the shortening of the right leg. Because the Board has determined that service connection for shortening of the right leg is not warranted, there is no basis for awarding service connection for a low back disorder. The Board has also determined, therefore, that the preponderance of the evidence is against the claim of entitlement to service connection for a low back disorder. ORDER The claim of entitlement to service connection for shortening of the right leg is denied. The claim of entitlement to service connection for a low back disorder is denied. Charles E. Hogeboom Member, Board of Veterans' Appeals IMPORTANT NOTICE: We have attached a VA Form 4597 that tells you what steps you can take if you disagree with our decision. We are in the process of updating the form to reflect changes in the law effective on December 27, 2001. See the Veterans Education and Benefits Expansion Act of 2001, Pub. L. No. 107-103, 115 Stat. 976 (2001). In the meanwhile, please note these important corrections to the advice in the form: ? These changes apply to the section entitled "Appeal to the United States Court of Appeals for Veterans Claims." (1) A "Notice of Disagreement filed on or after November 18, 1988" is no longer required to appeal to the Court. (2) You are no longer required to file a copy of your Notice of Appeal with VA's General Counsel. ? In the section entitled "Representation before VA," filing a "Notice of Disagreement with respect to the claim on or after November 18, 1988" is no longer a condition for an attorney-at-law or a VA accredited agent to charge you a fee for representing you.