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Achilles Tendon Lengthening for Equinus Foot with Miyoshi Myopathy: A Case Report
The Journal of Foot & Ankle Surgery xxx (2014) 1–4
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Case Reports and Series
Achilles Tendon Lengthening for Equinus Foot with Miyoshi Myopathy: A Case Report Kazuya Ikoma, MD, PhD, Masahiro Maki, MD, PhD, Masamitsu Kido, MD, PhD, Yuji Arai, MD, PhD, Hiroyoshi Fujiwara, MD, PhD, Toshikazu Kubo, MD, PhD Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 4
A 17-year-old male presented with reduced muscle strength in both lower limbs and demonstrated equinus foot (ankle equinus) in the right lower limb. Using dysferlin immunostaining, the patient was diagnosed with Miyoshi myopathy by the neurologist. Achilles tendon lengthening was performed, and a plantigrade foot without ankle equinus was achieved. Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved.
Keywords: ankle equinus dysferlin gastrosoleus equinus muscular dystrophy surgery triceps surae
Miyoshi myopathy is a hereditary muscle disorder that affects the distal limb muscles (1,2). It is inherited as an autosomal recessive trait (3); however, its epidemiology remains unclear. In particular, the initial lesions usually occur in the triceps surae muscle, and the progression is typically slow. However, weakness can also affect the anterior muscles of the legs. Patients will mainly present with difficulties climbing and descending stairs and walking on tiptoe (4). As far as we know, however, to date, no reports have been published of surgical treatment of this condition when symptomatic equinus foot (ankle equinus) inhibits ambulation. In the present report, we describe the case of a young male patient in whom we performed Achilles tendon lengthening for the treatment of Miyoshi myopathy in which the initial lesions were noted in the gastrocnemius muscle and for whom a plantigrade gait had become impossible owing to the occurrence of an equinus foot. Case Report A 17-year-old male presented with complaints mainly of reduced muscle strength in both lower limbs and demonstrated equinus foot in the right lower limb. From around the age of 15 years, he had, for no particular reason, found it difficult to walk on tiptoe. He was also Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Kazuya Ikoma, MD, PhD, Department of Orthopaedics, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kawaramachi- Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan. E-mail address: [email protected] (K. Ikoma).
aware of a lack of strength in both lower limbs with other activity, including ascending and descending stairs. Subsequently, he had experienced restricted dorsiflexion strength in the muscles of both legs and had gradually begun to have difficulty placing his right heel on the ground while walking. He had consulted another doctor when he experienced back pain and was referred to our hospital for a detailed examination. The local findings included a straight leg raise test that revealed 60 on the right and 70 on the left, indicative of tight hamstrings. Also, his deep tendon reflexes tested normally for both the left and the right patellar and Achilles tendon reflexes. No impairment of sensory perception was noted in either lower limb, and the Daniels and Worthingham manual muscle (strength) testing showed his muscle strength to be level 4 (good, but not normal) bilaterally in the triceps surae muscle group (5). The degree of dorsiflexion in the ankle joints was 20 on the right and 0 on the left, and the degree of plantar flexion was 45 for the left and right sides. On standing, the patient found it impossible to connect his right heel to the ground, secondary to contracture of his triceps surae and Achilles tendon (Fig. 1). The circumference below the knee was 30 cm on both the left and right at 10 cm distal to the tibial tuberosity. Plain radiographs showed inversion deformity of the right hindfoot and a flatfoot deformity in the left foot (Fig. 2). Lumbar magnetic resonance imaging scans did not indicate any particular abnormalities, and no evidence was found of lumbar disc herniation or lumbar canal stenosis. The blood and laboratory test results revealed the lactase dehydrogenase level to be 535 IU/L, creatine kinase of 7545 IU/L, consistent with the elevation of these myogenic enzymes. A myogenic condition was suspected, and the patient was referred for neurologic consultation. The neurologic examination confirmed the presence of
1067-2516/$ - see front matter Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.01.007
2
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
Fig. 1. A photograph from the dorsal side before surgery showing a marked wasting of the gastrocnemius musculature.
atrophy of both gastrocnemius muscles, and this was further documented from magnetic resonance imaging scans of the legs (Fig. 3). Biopsy and hematoxylin and eosin staining of the gastrocnemius musculature revealed inconsistent muscle cell sizes and interstitial fibrosis (Fig. 4). Immunostaining revealed the uneven, sporadic presence of the membrane protein dysferlin (Fig. 5). From these findings, the patient was diagnosed with Miyoshi myopathy by the neurologist, and, after discussions with the patient and preparation in
our orthopedics department, the patient’s equinus foot was treated using a brace. However, this led to pain in the anterior leg and additional difficulty in walking. Moreover, his activities of daily living (ADLs) became progressively more difficult to perform, and his Japanese Society for Surgery of the Foot score (6,7) was 78 points, consistent with difficulty performing his ADLs. Therefore, we recommended, and the patient agreed to, lengthening of the Achilles tendon on his right leg. Under general anesthesia, with the patient in the prone position, a curvilinear incision was made medial to the posterior midline of the leg, and the dissection was carried though the paratenon to expose the Achilles tendon, after which axial incisions were made across half of the Achilles tendon, posteromedially at approximately 1 cm from the area at which the Achilles tendon inserts into the calcaneus and externally at approximately 8 cm proximal to that point. Thereafter, a 4-cm slide lengthening of the Achilles tendon was achieved by dorsiflexing the ankle with the knee extended. A sterile bandage was applied after layered wound closure, and the patient’s right ankle was immobilized for 3 weeks in a below-theknee plaster cast. Subsequent to its removal, he was fitted with an articulated foot orthosis that restricted ankle dorsiflexion for an additional 4 weeks. After removal of the cast, the patient was permitted to place his full weight on his foot to walk, subject to pain limitations. He was able to walk with full weightbearing on the foot 2 weeks later. His postoperative course progressed uneventfully. On examination 2 years after the surgery, we found no difference between his left and right ankles in terms of the lower leg circumference, dorsiflexion had improved to 0 , and his right foot remained plantigrade (Fig. 6). Walking could be maintained; however, owing to the Miyoshi myopathy, performing the single heel rise test was impossible for both legs. The circumference of his calf at 10 cm distal to the tibial tuberosity was 30 cm bilaterally. Furthermore, the patient’s Japanese Society for Surgery of the Foot score had improved to 92 points. Because he was able to maintain the plantigrade position of his foot and a neutral ankle, his ability to walk had improved, and the patient was satisfied with his treatment results. Discussion Miyoshi myopathy (1,2) is a hereditary muscle disorder (inherited as an autosomal recessive trait) (3) that occurs mainly in the distal limb muscles of young people. It is caused by a deficiency in the
Fig. 2. Preoperative radiographs of (A) right and (B) left ankles showing a marked equines foot.
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
3
Fig. 3. Axial spectral presaturation with inversion recovery magnetic resonance image of both legs of the patient demonstrating the atrophy of the gastrocnemius muscle.
membrane protein dysferlin within muscle tissue. The condition occurs as a result of mutation of the dysferlin gene (8). It occurs in those aged 15 to 30 years, and the initial symptoms tend to be difficulty in climbing and descending stairs and being unable to perform a plantigrade gait (4). Irregularly high levels of creatine kinase, found by blood and laboratory testing, are characteristic (9). If the posterior muscles in the lower leg, mainly the gastrocnemius and soleus muscles, are confirmed to be atrophied, the condition is considered to be advanced. As this disease progresses, the lower leg anterior muscles and lower limb proximal muscles will also demonstrate lesions, and such patients will experience difficulty in walking. A confirmed diagnosis requires a muscle biopsy, in which dysferlin immunostaining will confirm the presence of this deficiency. No treatment has yet been established. In the present patient, along with atrophy of the gastrocnemius muscle, the patient had restricted dorsal flexion in the ankle joint. His foot had developed an equinus foot, making the plantigrade position difficult. His muscle strength remained, but the equinus foot was causing disability in regard to walking, and he was treated with braces. On the other side, lesions in the gastrocnemius muscle were noted, resulting from Miyoshi myopathy, and his muscle strength was reduced; however, flatfoot deformity had occurred, and a plantigrade gait was possible. The differences in the deformation between the right and left legs, however, meant that the length of his lower limbs was different. Also, because the brace treatment did not appear to have improved his walking difficulties, Achilles tendon lengthening was implemented to improve his walking ability. To the best of our knowledge, no reports have been published of treatment of Miyoshi myopathy using orthopedic surgery. It has been thought that the effects on the lower leg posterior muscles in the early
Fig. 4. Hematoxylin and eosin staining of gastrocnemius muscle (total magnification 100).
Fig. 5. Immunohistochemical staining of gastrocnemius muscle (total magnification 100).
stages of the condition will lead to an equinus foot in many cases; however, to date, it has been thought that conservative treatment should be performed using an orthosis. Achilles tendon lengthening reduces the muscle strength and could be thought to potentially worsen the difficulties in walking. However, it can be considered appropriate to implement Achilles tendon lengthening to improve existing ADLs for patients with difficulties walking using a brace and disease progression. In the present case, we performed sliding tendon lengthening during surgery. Sliding tendon lengthening did not cause any difference in the circumference of the below the knee
Fig. 6. Photograph from the dorsal side after surgery showing the patient standing with a plantigrade position.
4
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
circumference between the left and right legs, and the patient was satisfied with the results. We believe that performing Achilles tendon lengthening, using sliding tendon lengthening, to facilitate early improvements in plantigrade gait disorder caused by Miyoshi myopathy can allow the expectation of improvements in ADLs. In conclusion, we implemented Achilles tendon lengthening to treat a case of equinus foot caused by Miyoshi myopathy. As a result, a plantigrade gait became possible, and the patient was satisfied. We believe that the implementation of Achilles tendon lengthening to treat equinus foot caused by Miyoshi myopathy can contribute to improvements in the patient’s ADLs. References 1. Barohn RJ, Miller RG, Griggs RC. Autosomal recessive distal dystrophy. Neurology 41:1365–1370, 1991. 2. Miyoshi K, Kawai H, Iwasa M, Kusaka K, Nishino H. Autosomal recessive distal muscular dystrophy as a new type of progressive muscular dystrophy: seventeen cases in eight families including an autopsied case. Brain 109:31–54, 1986.
3. Bejaoui K, Hirabayashi K, Hentati F, Haines JL, Ben Hamida C, Belal S, Miller RG, McKenna-Yasek D, Weissenbach J, Rowland LP, Griggs RC, Munsat TL, Ben Hamida M, Arahata K, Brown RH Jr. Linkage of Miyoshi myopathy (distal autosomal recessive muscular dystrophy) locus to chromosome 2p12-14. Neurology 45:768–772, 1995. 4. Barthelemy F, Wein N, Krahn M, Levy N, Bartoli M. Translational research and therapeutic perspectives in dysferlinopathies. Mol Med 17:875–882, 2011. 5. Hislop HJ, Avers D, Brown M. Testing the muscles of the lower extremity. In: Daniels and Worthingham’s Muscle Testing: Techniques of Manual Examination and Performance Testinged 9, Elsevier, Philadelphia, PA, 2013, pp. 203–275. 6. Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y, Takao M, Tanaka Y. Development of the patient-based outcome instrument for the foot and ankle. Part 1: project description and evaluation of the Outcome Instrument version 1. J Orthop Sci 16:536–554, 2011. 7. Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y, Takao M, Tanaka Y. Development of the patient-based outcome instrument for foot and ankle: part 2: results from the second field survey: validity of the Outcome Instrument for the foot and ankle version 2. J Orthop Sci 16:556–564, 2011. 8. Liu J, Aoki M, Illa I, Wu C, Fardeau M, Angelini C, Serrano C, Urtizberea JA, Hentati F, Hamida MB, Bohlega S, Culper EJ, Amato AA, Bossie K, Oeltjen J, Bejaoui K, McKenna-Yasek D, Hosler BA, Schurr E, Arahata K, de Jong PJ, Brown RH Jr. Dysferlin, a novel skeletal muscle gene, is mutated in Miyoshi myopathy and limb girdle muscular dystrophy. Nat Genet 20:31–36, 1998. 9. Illa I. Distal myopathies. J Neurol 247:169–174, 2000.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Case Reports and Series
Achilles Tendon Lengthening for Equinus Foot with Miyoshi Myopathy: A Case Report Kazuya Ikoma, MD, PhD, Masahiro Maki, MD, PhD, Masamitsu Kido, MD, PhD, Yuji Arai, MD, PhD, Hiroyoshi Fujiwara, MD, PhD, Toshikazu Kubo, MD, PhD Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 4
A 17-year-old male presented with reduced muscle strength in both lower limbs and demonstrated equinus foot (ankle equinus) in the right lower limb. Using dysferlin immunostaining, the patient was diagnosed with Miyoshi myopathy by the neurologist. Achilles tendon lengthening was performed, and a plantigrade foot without ankle equinus was achieved. Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved.
Keywords: ankle equinus dysferlin gastrosoleus equinus muscular dystrophy surgery triceps surae
Miyoshi myopathy is a hereditary muscle disorder that affects the distal limb muscles (1,2). It is inherited as an autosomal recessive trait (3); however, its epidemiology remains unclear. In particular, the initial lesions usually occur in the triceps surae muscle, and the progression is typically slow. However, weakness can also affect the anterior muscles of the legs. Patients will mainly present with difficulties climbing and descending stairs and walking on tiptoe (4). As far as we know, however, to date, no reports have been published of surgical treatment of this condition when symptomatic equinus foot (ankle equinus) inhibits ambulation. In the present report, we describe the case of a young male patient in whom we performed Achilles tendon lengthening for the treatment of Miyoshi myopathy in which the initial lesions were noted in the gastrocnemius muscle and for whom a plantigrade gait had become impossible owing to the occurrence of an equinus foot. Case Report A 17-year-old male presented with complaints mainly of reduced muscle strength in both lower limbs and demonstrated equinus foot in the right lower limb. From around the age of 15 years, he had, for no particular reason, found it difficult to walk on tiptoe. He was also Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Kazuya Ikoma, MD, PhD, Department of Orthopaedics, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kawaramachi- Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan. E-mail address: [email protected] (K. Ikoma).
aware of a lack of strength in both lower limbs with other activity, including ascending and descending stairs. Subsequently, he had experienced restricted dorsiflexion strength in the muscles of both legs and had gradually begun to have difficulty placing his right heel on the ground while walking. He had consulted another doctor when he experienced back pain and was referred to our hospital for a detailed examination. The local findings included a straight leg raise test that revealed 60 on the right and 70 on the left, indicative of tight hamstrings. Also, his deep tendon reflexes tested normally for both the left and the right patellar and Achilles tendon reflexes. No impairment of sensory perception was noted in either lower limb, and the Daniels and Worthingham manual muscle (strength) testing showed his muscle strength to be level 4 (good, but not normal) bilaterally in the triceps surae muscle group (5). The degree of dorsiflexion in the ankle joints was 20 on the right and 0 on the left, and the degree of plantar flexion was 45 for the left and right sides. On standing, the patient found it impossible to connect his right heel to the ground, secondary to contracture of his triceps surae and Achilles tendon (Fig. 1). The circumference below the knee was 30 cm on both the left and right at 10 cm distal to the tibial tuberosity. Plain radiographs showed inversion deformity of the right hindfoot and a flatfoot deformity in the left foot (Fig. 2). Lumbar magnetic resonance imaging scans did not indicate any particular abnormalities, and no evidence was found of lumbar disc herniation or lumbar canal stenosis. The blood and laboratory test results revealed the lactase dehydrogenase level to be 535 IU/L, creatine kinase of 7545 IU/L, consistent with the elevation of these myogenic enzymes. A myogenic condition was suspected, and the patient was referred for neurologic consultation. The neurologic examination confirmed the presence of
1067-2516/$ - see front matter Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.01.007
2
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
Fig. 1. A photograph from the dorsal side before surgery showing a marked wasting of the gastrocnemius musculature.
atrophy of both gastrocnemius muscles, and this was further documented from magnetic resonance imaging scans of the legs (Fig. 3). Biopsy and hematoxylin and eosin staining of the gastrocnemius musculature revealed inconsistent muscle cell sizes and interstitial fibrosis (Fig. 4). Immunostaining revealed the uneven, sporadic presence of the membrane protein dysferlin (Fig. 5). From these findings, the patient was diagnosed with Miyoshi myopathy by the neurologist, and, after discussions with the patient and preparation in
our orthopedics department, the patient’s equinus foot was treated using a brace. However, this led to pain in the anterior leg and additional difficulty in walking. Moreover, his activities of daily living (ADLs) became progressively more difficult to perform, and his Japanese Society for Surgery of the Foot score (6,7) was 78 points, consistent with difficulty performing his ADLs. Therefore, we recommended, and the patient agreed to, lengthening of the Achilles tendon on his right leg. Under general anesthesia, with the patient in the prone position, a curvilinear incision was made medial to the posterior midline of the leg, and the dissection was carried though the paratenon to expose the Achilles tendon, after which axial incisions were made across half of the Achilles tendon, posteromedially at approximately 1 cm from the area at which the Achilles tendon inserts into the calcaneus and externally at approximately 8 cm proximal to that point. Thereafter, a 4-cm slide lengthening of the Achilles tendon was achieved by dorsiflexing the ankle with the knee extended. A sterile bandage was applied after layered wound closure, and the patient’s right ankle was immobilized for 3 weeks in a below-theknee plaster cast. Subsequent to its removal, he was fitted with an articulated foot orthosis that restricted ankle dorsiflexion for an additional 4 weeks. After removal of the cast, the patient was permitted to place his full weight on his foot to walk, subject to pain limitations. He was able to walk with full weightbearing on the foot 2 weeks later. His postoperative course progressed uneventfully. On examination 2 years after the surgery, we found no difference between his left and right ankles in terms of the lower leg circumference, dorsiflexion had improved to 0 , and his right foot remained plantigrade (Fig. 6). Walking could be maintained; however, owing to the Miyoshi myopathy, performing the single heel rise test was impossible for both legs. The circumference of his calf at 10 cm distal to the tibial tuberosity was 30 cm bilaterally. Furthermore, the patient’s Japanese Society for Surgery of the Foot score had improved to 92 points. Because he was able to maintain the plantigrade position of his foot and a neutral ankle, his ability to walk had improved, and the patient was satisfied with his treatment results. Discussion Miyoshi myopathy (1,2) is a hereditary muscle disorder (inherited as an autosomal recessive trait) (3) that occurs mainly in the distal limb muscles of young people. It is caused by a deficiency in the
Fig. 2. Preoperative radiographs of (A) right and (B) left ankles showing a marked equines foot.
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
3
Fig. 3. Axial spectral presaturation with inversion recovery magnetic resonance image of both legs of the patient demonstrating the atrophy of the gastrocnemius muscle.
membrane protein dysferlin within muscle tissue. The condition occurs as a result of mutation of the dysferlin gene (8). It occurs in those aged 15 to 30 years, and the initial symptoms tend to be difficulty in climbing and descending stairs and being unable to perform a plantigrade gait (4). Irregularly high levels of creatine kinase, found by blood and laboratory testing, are characteristic (9). If the posterior muscles in the lower leg, mainly the gastrocnemius and soleus muscles, are confirmed to be atrophied, the condition is considered to be advanced. As this disease progresses, the lower leg anterior muscles and lower limb proximal muscles will also demonstrate lesions, and such patients will experience difficulty in walking. A confirmed diagnosis requires a muscle biopsy, in which dysferlin immunostaining will confirm the presence of this deficiency. No treatment has yet been established. In the present patient, along with atrophy of the gastrocnemius muscle, the patient had restricted dorsal flexion in the ankle joint. His foot had developed an equinus foot, making the plantigrade position difficult. His muscle strength remained, but the equinus foot was causing disability in regard to walking, and he was treated with braces. On the other side, lesions in the gastrocnemius muscle were noted, resulting from Miyoshi myopathy, and his muscle strength was reduced; however, flatfoot deformity had occurred, and a plantigrade gait was possible. The differences in the deformation between the right and left legs, however, meant that the length of his lower limbs was different. Also, because the brace treatment did not appear to have improved his walking difficulties, Achilles tendon lengthening was implemented to improve his walking ability. To the best of our knowledge, no reports have been published of treatment of Miyoshi myopathy using orthopedic surgery. It has been thought that the effects on the lower leg posterior muscles in the early
Fig. 4. Hematoxylin and eosin staining of gastrocnemius muscle (total magnification 100).
Fig. 5. Immunohistochemical staining of gastrocnemius muscle (total magnification 100).
stages of the condition will lead to an equinus foot in many cases; however, to date, it has been thought that conservative treatment should be performed using an orthosis. Achilles tendon lengthening reduces the muscle strength and could be thought to potentially worsen the difficulties in walking. However, it can be considered appropriate to implement Achilles tendon lengthening to improve existing ADLs for patients with difficulties walking using a brace and disease progression. In the present case, we performed sliding tendon lengthening during surgery. Sliding tendon lengthening did not cause any difference in the circumference of the below the knee
Fig. 6. Photograph from the dorsal side after surgery showing the patient standing with a plantigrade position.
4
K. Ikoma et al. / The Journal of Foot & Ankle Surgery xxx (2014) 1–4
circumference between the left and right legs, and the patient was satisfied with the results. We believe that performing Achilles tendon lengthening, using sliding tendon lengthening, to facilitate early improvements in plantigrade gait disorder caused by Miyoshi myopathy can allow the expectation of improvements in ADLs. In conclusion, we implemented Achilles tendon lengthening to treat a case of equinus foot caused by Miyoshi myopathy. As a result, a plantigrade gait became possible, and the patient was satisfied. We believe that the implementation of Achilles tendon lengthening to treat equinus foot caused by Miyoshi myopathy can contribute to improvements in the patient’s ADLs. References 1. Barohn RJ, Miller RG, Griggs RC. Autosomal recessive distal dystrophy. Neurology 41:1365–1370, 1991. 2. Miyoshi K, Kawai H, Iwasa M, Kusaka K, Nishino H. Autosomal recessive distal muscular dystrophy as a new type of progressive muscular dystrophy: seventeen cases in eight families including an autopsied case. Brain 109:31–54, 1986.
3. Bejaoui K, Hirabayashi K, Hentati F, Haines JL, Ben Hamida C, Belal S, Miller RG, McKenna-Yasek D, Weissenbach J, Rowland LP, Griggs RC, Munsat TL, Ben Hamida M, Arahata K, Brown RH Jr. Linkage of Miyoshi myopathy (distal autosomal recessive muscular dystrophy) locus to chromosome 2p12-14. Neurology 45:768–772, 1995. 4. Barthelemy F, Wein N, Krahn M, Levy N, Bartoli M. Translational research and therapeutic perspectives in dysferlinopathies. Mol Med 17:875–882, 2011. 5. Hislop HJ, Avers D, Brown M. Testing the muscles of the lower extremity. In: Daniels and Worthingham’s Muscle Testing: Techniques of Manual Examination and Performance Testinged 9, Elsevier, Philadelphia, PA, 2013, pp. 203–275. 6. Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y, Takao M, Tanaka Y. Development of the patient-based outcome instrument for the foot and ankle. Part 1: project description and evaluation of the Outcome Instrument version 1. J Orthop Sci 16:536–554, 2011. 7. Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y, Takao M, Tanaka Y. Development of the patient-based outcome instrument for foot and ankle: part 2: results from the second field survey: validity of the Outcome Instrument for the foot and ankle version 2. J Orthop Sci 16:556–564, 2011. 8. Liu J, Aoki M, Illa I, Wu C, Fardeau M, Angelini C, Serrano C, Urtizberea JA, Hentati F, Hamida MB, Bohlega S, Culper EJ, Amato AA, Bossie K, Oeltjen J, Bejaoui K, McKenna-Yasek D, Hosler BA, Schurr E, Arahata K, de Jong PJ, Brown RH Jr. Dysferlin, a novel skeletal muscle gene, is mutated in Miyoshi myopathy and limb girdle muscular dystrophy. Nat Genet 20:31–36, 1998. 9. Illa I. Distal myopathies. J Neurol 247:169–174, 2000.