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Congenital anomalies of the little finger
Congenital Anomalies of the Little Finger MIURA and SHUHEI TORI1 From Nagoya University, Japan.
TAKAYUKI
Clinical features of congenital hypoplastic and extension contractures of the little finger were studied. There are eight groups. Characteristic features of each group are described. Each type has distinguishable clinical features in typical cases, but in some cases the condition of shortening of the phalanges and narrowing of the joint space is not clear.
patients with hypoplasia or had thirty-eight extension contractures of the little finger other than those of camptodactyly, Kirner’s deformity, and hypoplastic little finger accompanied by major anomalies. These patients can be divided into eight groups according to the characteristic features of the little finger. We
Type I: The shortened middle phalanx is shaped like a delta phalanx. Type 2: The middle phalanx is shortened with a narrowed space at the proximal interphalangeal joint. Type 3: The middle phalanx is shortened with a narrow space at the distal interphalngeal joint. Type 4: The middle phalanx is not shortened and the round surface of the proximal phalangeal head is transformed and flattened. Type 5: Typical symphalangism. Type 6: The flexor tendon of the little finger is absent or hypoplastic. Type 7: The interdigital space between the ring and little fingers is deep like a split hand, and the little finger is hypoplastic.
Except for those anomalies whose clinical features were already known, thirty-eight patients complained of hypoplasia and/or extension contractures of the interphalangeal joint in the little finger. There have been few reports of hypoplasia and/or contracture of the little finger, because these anomalies are rare, and the disability caused by these anomalies is relatively slight. Kelikian (1974) considers these anomalies, where extension contracture is found in the little finger only, may be included under symphalangism. However, we thought there were several differences between symphalangism and extension contracture of the little finger. In this series we would like to clarify the clinical features of these anomalies and divide them into several groups according to the characteristic features of the little finger. There are eight distinguishable clinical types of anomalies. Type 1 (Figure I) The shortened triangular middle phalanx has an epiphysis running along the shortened side of the phalanx in a proximal to distal direction, delta phalanx. It may be only one type of brachymesophalangy 5, but it has such clearly distinguishable features that we would like to classify it as a separate group. However, we have not been able to distinguish delta phalanx from triangular shortened phalanges before the epiphyseal line appears and after the epiphyseal arrest. Some of the clinodactyly of the little finger may be of this type.
Type 8: The distal phalanges lack the crescent-shaped cap and blunt Y-shaped bony projection. Nail formation is found in the ectopic palmar area. Brachymesophalangy of the little finger is a common congenital anomaly in Japanese. Sugiura (1976) reported that the incidence of brachymesophalangy 5 in Japanese males was 14.7% and in females 23.4%. Camptodactyly, flexion contracture of proximal interphalangeal joint, and Kirner’s deformity, of the distal phalanges, are familiar congenital anomalies found in the little finger. Hypoplasia and extension contracture of the interphalangeal joint in the little finger are also accompanied by so-called atypical split hand and symbrachydactyly. Received for publication August 1984. Dr. Takayuki Miura, M.D. Nagoya University, 466.
VOL.
10-B No.
2 JUNE
1985
65 Tsummacho,
Showaku,
Nagoya,
Japan
Fig. 1
Group 1.
245
TAKAYUKI
MIURA AND SHUHEI TORI1
Fig. 3
Group 3.
Type 4 (Figure 4) There is no shortening of the middle phalanges and the proximal interphalangeal joint space is relatively wide. However, the round surface of the proximal phalangeal head is transformed and flattened. Active and passive flexion at the proximal interphalangeal joint is restricted. There were seven patients, five males and two females, four bilateral and three unilateral. One of the seven patients had the same anomaly in the ring finger proximal interphalangeal joint. It is difficult to distinguish some patients of this type from type 2 or type 5.
Fig. 2
Group 2.
Type 2 (Figure 2) The middle phalanges are shortened with narrowed joint space in the proximal interphalangeal joint, which may be fused between the proximal and middle phalanges. Flexion at the distal interphalangeal joint is not restricted. Although in some patients restricted flexion at the proximal interphalangeal joint, may be found, most patients cannot flex the affected proximal interphalangeal joint. There were eleven patients, seven males and four females, ten bilateral and one unilateral. Hereditary anomaly was seen in only one out of the eleven patients, his father, grandmother and other members of the family complained of the same anomalies. Fig. 4
Type 3 (Figure 3) The middle phalanges are shortened with a narrow joint space in the distal interphalangeal joint, which may be fused between the middle and distal phalanges. There were only three patients with this anomaly, all female. One of the three patients had complications of postaxial polydactyly and another one had shortening of the middle phalanges of the ring finger. 246
Group 4.
Type 5 (Figure 5) Type 5 is a typical symphalangism. There were three families with symphalangism. It was inherited according to the Mendelian autosomal dominant trait. Shortening of the middle phalanges was clear in some patients but in others it was uncertain, because the fusion between proximal and middle phalanges was complete. In all THE JOURNAL
OF HAND
SURGERY
CONGENITAL
Fig. 5
Group
5 (a) Mother
ANOMALIES
OF THE LITTLE FINGER
(b) son. Fig. 6
Group
6.
++
Fig. 7
Group
7.
-
Type 8 (Figure 8) Narrowing of the joint space is not remarkable, but there is hypoplasia of the affected fingers to some degree. Active and passive flexion of the interphalangeal joint is restricted. The distal phalanges of the affected finger lack the crescent-shaped cap and have a blunt Y-shaped bony projection. Nail formation is found in the ectopic palmar area (Miura, 1978). There were two families of this type consisting of four patients and three sporadic patients, five males and two females.
patients but one the fusion of the phalangeal bone was not limited to the little finger. Differentiation between isolated cases and type 2 anomaly may be difficult. Each type from 2 to 5 has distinguishable clinical features in typical cases, but in some cases, especially in early life, the shortening of the phalanges and narrowing of the joint spaces are not clear. Therefore, we must be careful in diagnosing symphalangism if the patients complaints are sporadic and limited to the little finger only (Table 1). TABLE 1 Characteristic feature (Type ~-TYD~ 5) brachymesophalangy TYPO 2 Type 3 TYPO 4 Type 5
mm0 wing of PIP joint
hypoplasia of distal phalanx
+
+ - ++ -
+
+ ++
+ + * -
+ -
++
narrowing of DIP joint
Type 6 (Figure 6) The interphalangeal joint is able to flex passively but cannot flex actively, because the flexor tendons or muscles of the little finger are congenitally absent or hypoplastic. The little finger is hypoplastic but shows no remarkable changes of the phalanges and joint space. There were two male patients of this type. The flexor digitorum superficialis tendon of the ring finger was transferred in one patient to restore the flexion, but only a limited flexion, about forty degrees, was obtained. Type 7 (Figure 7) The interphalangeal space between the ring and little fingers is deep like a split hand, and the little finger is hypoplastic to some degree. There were two male patients of this type. Web-formation between middle and ring fingers was seen in one patient. VOL. 10-B No. 2 JUNE 1985
In two patients typical anomalies are found more in the ring finger than in the little finger. In one patient, the skin on the palmar aspect was similar to dorsal skin in colour and character. Extensor hood tenolysis was performed in one patient, but without improvement. In such cases resection of the nail on the ectopic area may be recommended but real indication for operation is rare, because the mobility of the affected finger is limited and precision handling cannot be expected whether the nail is resected or not. 247
TAKAYUKI MIURA AND SHUHEI TORI1
References KELIKIAN, H. Congenital Deformities of the Hand and Forearm. Philadelphia London Toronto. W. B. Saunders Company (1974). MIURA. T. (19781. Two families with congenital nail anomalies: Nail formation- in ectopic areas. The Journal of Hand Surgery 3: 348-351. SUGIURA, Y. and NAKAZAWA, 0. Bone Age-Roentgen Diagnosis of Skeletal Development. 3rd Edition Tokyo Chugaiigaku Company (1976).
Fig. 8
248
Group
8.
THE JOURNAL OF HAND SURGERY
TAKAYUKI
Clinical features of congenital hypoplastic and extension contractures of the little finger were studied. There are eight groups. Characteristic features of each group are described. Each type has distinguishable clinical features in typical cases, but in some cases the condition of shortening of the phalanges and narrowing of the joint space is not clear.
patients with hypoplasia or had thirty-eight extension contractures of the little finger other than those of camptodactyly, Kirner’s deformity, and hypoplastic little finger accompanied by major anomalies. These patients can be divided into eight groups according to the characteristic features of the little finger. We
Type I: The shortened middle phalanx is shaped like a delta phalanx. Type 2: The middle phalanx is shortened with a narrowed space at the proximal interphalangeal joint. Type 3: The middle phalanx is shortened with a narrow space at the distal interphalngeal joint. Type 4: The middle phalanx is not shortened and the round surface of the proximal phalangeal head is transformed and flattened. Type 5: Typical symphalangism. Type 6: The flexor tendon of the little finger is absent or hypoplastic. Type 7: The interdigital space between the ring and little fingers is deep like a split hand, and the little finger is hypoplastic.
Except for those anomalies whose clinical features were already known, thirty-eight patients complained of hypoplasia and/or extension contractures of the interphalangeal joint in the little finger. There have been few reports of hypoplasia and/or contracture of the little finger, because these anomalies are rare, and the disability caused by these anomalies is relatively slight. Kelikian (1974) considers these anomalies, where extension contracture is found in the little finger only, may be included under symphalangism. However, we thought there were several differences between symphalangism and extension contracture of the little finger. In this series we would like to clarify the clinical features of these anomalies and divide them into several groups according to the characteristic features of the little finger. There are eight distinguishable clinical types of anomalies. Type 1 (Figure I) The shortened triangular middle phalanx has an epiphysis running along the shortened side of the phalanx in a proximal to distal direction, delta phalanx. It may be only one type of brachymesophalangy 5, but it has such clearly distinguishable features that we would like to classify it as a separate group. However, we have not been able to distinguish delta phalanx from triangular shortened phalanges before the epiphyseal line appears and after the epiphyseal arrest. Some of the clinodactyly of the little finger may be of this type.
Type 8: The distal phalanges lack the crescent-shaped cap and blunt Y-shaped bony projection. Nail formation is found in the ectopic palmar area. Brachymesophalangy of the little finger is a common congenital anomaly in Japanese. Sugiura (1976) reported that the incidence of brachymesophalangy 5 in Japanese males was 14.7% and in females 23.4%. Camptodactyly, flexion contracture of proximal interphalangeal joint, and Kirner’s deformity, of the distal phalanges, are familiar congenital anomalies found in the little finger. Hypoplasia and extension contracture of the interphalangeal joint in the little finger are also accompanied by so-called atypical split hand and symbrachydactyly. Received for publication August 1984. Dr. Takayuki Miura, M.D. Nagoya University, 466.
VOL.
10-B No.
2 JUNE
1985
65 Tsummacho,
Showaku,
Nagoya,
Japan
Fig. 1
Group 1.
245
TAKAYUKI
MIURA AND SHUHEI TORI1
Fig. 3
Group 3.
Type 4 (Figure 4) There is no shortening of the middle phalanges and the proximal interphalangeal joint space is relatively wide. However, the round surface of the proximal phalangeal head is transformed and flattened. Active and passive flexion at the proximal interphalangeal joint is restricted. There were seven patients, five males and two females, four bilateral and three unilateral. One of the seven patients had the same anomaly in the ring finger proximal interphalangeal joint. It is difficult to distinguish some patients of this type from type 2 or type 5.
Fig. 2
Group 2.
Type 2 (Figure 2) The middle phalanges are shortened with narrowed joint space in the proximal interphalangeal joint, which may be fused between the proximal and middle phalanges. Flexion at the distal interphalangeal joint is not restricted. Although in some patients restricted flexion at the proximal interphalangeal joint, may be found, most patients cannot flex the affected proximal interphalangeal joint. There were eleven patients, seven males and four females, ten bilateral and one unilateral. Hereditary anomaly was seen in only one out of the eleven patients, his father, grandmother and other members of the family complained of the same anomalies. Fig. 4
Type 3 (Figure 3) The middle phalanges are shortened with a narrow joint space in the distal interphalangeal joint, which may be fused between the middle and distal phalanges. There were only three patients with this anomaly, all female. One of the three patients had complications of postaxial polydactyly and another one had shortening of the middle phalanges of the ring finger. 246
Group 4.
Type 5 (Figure 5) Type 5 is a typical symphalangism. There were three families with symphalangism. It was inherited according to the Mendelian autosomal dominant trait. Shortening of the middle phalanges was clear in some patients but in others it was uncertain, because the fusion between proximal and middle phalanges was complete. In all THE JOURNAL
OF HAND
SURGERY
CONGENITAL
Fig. 5
Group
5 (a) Mother
ANOMALIES
OF THE LITTLE FINGER
(b) son. Fig. 6
Group
6.
++
Fig. 7
Group
7.
-
Type 8 (Figure 8) Narrowing of the joint space is not remarkable, but there is hypoplasia of the affected fingers to some degree. Active and passive flexion of the interphalangeal joint is restricted. The distal phalanges of the affected finger lack the crescent-shaped cap and have a blunt Y-shaped bony projection. Nail formation is found in the ectopic palmar area (Miura, 1978). There were two families of this type consisting of four patients and three sporadic patients, five males and two females.
patients but one the fusion of the phalangeal bone was not limited to the little finger. Differentiation between isolated cases and type 2 anomaly may be difficult. Each type from 2 to 5 has distinguishable clinical features in typical cases, but in some cases, especially in early life, the shortening of the phalanges and narrowing of the joint spaces are not clear. Therefore, we must be careful in diagnosing symphalangism if the patients complaints are sporadic and limited to the little finger only (Table 1). TABLE 1 Characteristic feature (Type ~-TYD~ 5) brachymesophalangy TYPO 2 Type 3 TYPO 4 Type 5
mm0 wing of PIP joint
hypoplasia of distal phalanx
+
+ - ++ -
+
+ ++
+ + * -
+ -
++
narrowing of DIP joint
Type 6 (Figure 6) The interphalangeal joint is able to flex passively but cannot flex actively, because the flexor tendons or muscles of the little finger are congenitally absent or hypoplastic. The little finger is hypoplastic but shows no remarkable changes of the phalanges and joint space. There were two male patients of this type. The flexor digitorum superficialis tendon of the ring finger was transferred in one patient to restore the flexion, but only a limited flexion, about forty degrees, was obtained. Type 7 (Figure 7) The interphalangeal space between the ring and little fingers is deep like a split hand, and the little finger is hypoplastic to some degree. There were two male patients of this type. Web-formation between middle and ring fingers was seen in one patient. VOL. 10-B No. 2 JUNE 1985
In two patients typical anomalies are found more in the ring finger than in the little finger. In one patient, the skin on the palmar aspect was similar to dorsal skin in colour and character. Extensor hood tenolysis was performed in one patient, but without improvement. In such cases resection of the nail on the ectopic area may be recommended but real indication for operation is rare, because the mobility of the affected finger is limited and precision handling cannot be expected whether the nail is resected or not. 247
TAKAYUKI MIURA AND SHUHEI TORI1
References KELIKIAN, H. Congenital Deformities of the Hand and Forearm. Philadelphia London Toronto. W. B. Saunders Company (1974). MIURA. T. (19781. Two families with congenital nail anomalies: Nail formation- in ectopic areas. The Journal of Hand Surgery 3: 348-351. SUGIURA, Y. and NAKAZAWA, 0. Bone Age-Roentgen Diagnosis of Skeletal Development. 3rd Edition Tokyo Chugaiigaku Company (1976).
Fig. 8
248
Group
8.
THE JOURNAL OF HAND SURGERY