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Restoration of the Central Slip in Congenital Form of Boutonniere Deformity: Case Report
SCIENTIFIC ARTICLE
Restoration of the Central Slip in Congenital Form of Boutonniere Deformity: Case Report Jong-Pil Kim, MD, Jai-Hyang Go, MD, Chang-Hwan Hwang, MD, Won-Jeong Shin, MS We present a case of a congenital form of a boutonniere deformity involving both little fingers with a poorly differentiated extensor mechanism and the absence of the tendinous attachment on the dorsal aspect of the middle phalanx. This complex deformity was evaluated histologically followed by successful reconstruction of the central slip. (J Hand Surg Am. 2014;39(10):1978e1981. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Key words Congenital deformity, boutonniere deformity, extensor mechanism, reconstruction.
B
OUTONNIERE DEFORMITY IS A RARE congenital disorder. It has been frequently confused with other flexion deformities such as congenital trigger digits or camptodactyly.1e3 Although the pathological features vary, attenuation of the central slip without disruption at its insertion has been noted.3,4 We present a case of a congenital boutonniere deformity in both little fingers with a poorly differentiated extensor mechanism and the absence of tendinous fixation of the central slip on the dorsal aspect of the middle phalanx. The proximal interphalangeal joint maintained a flexed position without volar subluxation of the lateral bands, which contradicted the usual chronic pathological condition. The rudimentary tissue of the central slip was examined histologically at its insertion, followed by successful reconstruction of the extensor mechanism. This was performed by dividing the conjoined tendon into
From the Department of Orthopedic Surgery, Department of Kinesiology and Medical Science, and Department of Pathology, Dankook University College of Medicine, Cheonan, Korea. Received for publication February 18, 2014; accepted in revised form May 22, 2014. The authors acknowledge Dr. Kyung Joon Lee for his effort in manuscript. Supported by the research fund of Dankook University in 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Jong-Pil Kim, MD, Department of Orthopedic Surgery, Dankook University College of Medicine, 359 Manghyangro, Dongnam-gu, Cheonan 330-715, Korea; e-mail: [email protected]. 0363-5023/14/3910-0013$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2014.05.030
1978
r
Ó 2014 ASSH
r
Published by Elsevier, Inc. All rights reserved.
3 slips and fixing the central slip to the base of the middle phalanx. The patient was informed that data from the case would be submitted for publication and gave consent. CASE REPORT A 26-year-old man presented with the inability to extend both little fingers, which was first noticed in early childhood. He denied any history of local trauma or a family history of a similar deformity. Systemic conditions possibly related to the deformity, including rheumatoid arthritis, neuromuscular disorders, connective tissue disease, or other skeletal deformities, were not noted. The patient had a 60 extension lag of the proximal interphalangeal joint and a 30 hyperextension of the distal interphalangeal joint on his left little finger during active finger extension. The little finger had full active flexion (Fig. 1). The same problem was noted in his right little finger in a milder form (30 extension lag of the proximal interphalangeal joint and 25 hyperextension of the distal interphalangeal joint). Digital neurovascular and radiographic examinations were normal. A diagnosis of bilateral congenital boutonniere deformity was made. At surgery, a curvilinear incision was made over the dorsum of the digit from the proximal phalanx to the middle phalanx on the left little finger. The extensor mechanism seemed to be constituted of one conjoined tendon without discrete separation into a central slip and 2 lateral bands over the proximal
CONGENITAL BOUTONNIERE DEFORMITY
1979
FIGURE 1: Preoperative photographs of the hands, showing boutonniere deformity in both little fingers.
FIGURE 3: Schematic illustrations of central slip reconstruction.
not noted. Splitting of the extensor tendon over the proximal interphalangeal joint revealed that rudimentary tissue was present at the dorsal aspect of the middle phalanx instead of a normal insertion of the central slip (Fig. 2). Lack of volar subluxation of the lateral bands without static contracture of the proximal interphalangeal joint suggested a loss of balance between the extensor and the flexors acting over the proximal interphalangeal joint during active finger extension on account of the extensor. The deformity was corrected by reconstructing the extensor mechanism, which was modified from techniques by Urbaniak and Hayes5 and Slesarenko et al.6 The central tendon flap was defined and elevated, dividing the conjoined tendon longitudinally into 3 slips. The central slip was advanced and sutured into the base of the middle phalanx using a suture anchor. The tendon slip was secured at the anatomical insertion of the central slip and was then additionally sutured to the elevated lateral slips with a nonabsorbable
FIGURE 2: Intraoperative photographs of the abnormal extensor mechanism over the proximal interphalangeal joint of the left little finger. A The extensor mechanism was composed of one conjoined tendon without development into 3 slips, which resulted in absence of the triangular ligament. B Splitting of the tendon demonstrated rudimentary insertion of central portion (asterisk).
interphalangeal joint (Fig. 2). This abnormal configuration of the extensor mechanism continued to its insertion, which may have led to failure of triangular ligament development. Furthermore, actual contracture of the transverse retinacular ligament was J Hand Surg Am.
r
Vol. 39, October 2014
1980
CONGENITAL BOUTONNIERE DEFORMITY
4-0 suture after the proximal interphalangeal joint was temporarily fixed in full extension using a Kirschner wire across the joint (Fig. 3). The same procedure was applied to the right little finger because it displayed the same findings intraoperatively. The fingers were immobilized with orthoses for 4 weeks, followed by a rehabilitation program after removal of the Kirschner wires. At the 22-month follow-up, the patient showed excellent finger motion with no residual deformity in his left hand and minimal extension lag at the proximal interphalangeal joint in his right hand. The histopathological assessment revealed myxoid degeneration with chondroid metaplasia of the rudimentary tissue at distal insertion of the central slip.
hood formed by the interosseous tendon and the lumbrical tendon, which transmit their force via the lateral bands to the distal phalanx, were not verified in this case. Furthermore, the lateral bands did not slip anterior to the axis of rotation of the proximal interphalangeal joint because they formed one conjoined tendon without developing into separate slips over the joint. Therefore, we speculate that hyperextension of the distal interphalangeal joint during extension was mainly caused by pull of the long extensor tendon rather than by pull of the intrinsic muscles or contracture of the oblique retinacular ligament. The flexion deformity of the proximal interphalangeal joint was created by the relatively stronger flexor digitorum superficialis, which becomes the dominant muscle in cases of a disrupted central slip.8 Histological changes in the remnant tissue at the tendon insertion site might be explained by the concept that histological characteristics can present in various forms on the gliding tendon, which usually indicates long tendons wrapped by a bony or fibrous pulley warping their straight direction.9 In our view, chondroid metaplasia of the remnant tissue underneath the conjoined tendon might occur due to gradient forces of the conjoined tendon, which is consistent with a previous report that the side of the tendon facing the source of compression is usually fibrocartilaginous.10 Various surgical procedures, including reattachment or reconstruction of the central slip, distal extensor tenotomy, tendon graft, and reconstruction of the transverse retinacular ligament, have been suggested for treating a chronic boutonniere deformity. Considering that passive extension of the proximal interphalangeal joint was not affected despite this unusual congenital deformity, the present case was treated by reconstructing the central slip, which was modified from techniques described by previous investigators.5,6 Our procedure consisted of elevating the central portion from the conjoined tendon, which may represent the central slip in a normal extensor mechanism, and securing it into the anatomic insertion of the central slip without additional reconstruction or release of the coordinating structures. Although this case does not represent a classic form, it extends our understanding of congenital boutonniere deformity and suggests a reliable surgical option.
DISCUSSION A chronic boutonniere deformity is characterized by flexion of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint, which result from imbalance between the long extensor-intrinsic complex acting over the dorsal aspect of the proximal interphalangeal joint and the flexor tendon volarly, contributing to increased tension in the lateral bands as they slip volarward.5,7,8 Carneiro and Lauderdale3 reported 5 congenital boutonniere deformities caused by attenuation of the central slip. They speculated that the attenuation was caused by an accident rather than a formation disorder occurring during embryogenesis. Lin et al4 reported a bilateral congenital boutonniere deformity with laxity of the central slip and believed that attenuation of the central slip occurred due to a developmental error in formation of the tendon and was aggravated by relatively powerful flexor tendons. Our case revealed a trifurcation failure of the extensor tendon over the proximal interphalangeal joint, which represented formation of one conjoined tendon without separation into one central slip and 2 lateral bands. A failure to develop bilateral lateral bands affects proper function of the transverse and oblique retinacular ligament, which control movement of the lateral bands either in flexion or extension of the proximal interphalangeal joint.7 Consequently, considering that deficiency of the structures coordinating extension of the finger mainly contributed to formation of the deformity in the present case, we postulate that a congenital form of boutonniere deformity represents various embryonic developmental failures. In contrast to a chronic traumatic boutonniere deformity, the thickened free margins of the extensor J Hand Surg Am.
REFERENCES 1. Koman LA, Toby EB, Poehling GG. Congenital flexion deformities of the proximal interphalangeal joint in children: a subgroup of camptodactyly. J Hand Surg Am. 1990;15(4):582e586.
r
Vol. 39, October 2014
CONGENITAL BOUTONNIERE DEFORMITY
2. Tsuge K. Congenital aplasia or hypoplasia of the finger extensors. Hand. 1975;7(1):15e21. 3. Carneiro RS. Congenital attenuation of the extensor tendon central slip. J Hand Surg Am. 1993;18(6):1004e1007. 4. Lin SC, Chiu HY. A nonexcision plication method for treatment of bilateral congenital boutonniere deformity: a preoperative biomechanical calculation. Plast Reconstr Surg. 2004;113(6): 1742e1745. 5. Urbaniak JR, Hayes MG. Chronic boutonniere deformity—an anatomic reconstruction. J Hand Surg Am. 1981;6(4): 379e383.
J Hand Surg Am.
1981
6. Slesarenko YA, Hurst LC, Mai K. Suture anchor technique for anatomic reconstruction in chronic boutonniere deformity. Tech Hand Up Extrem Surg. 2005;9(3):172e174. 7. Souter WA. The problem of boutonniere deformity. Clin Orthop Relat Res. 1974;104:116e133. 8. To P, Watson JT. Boutonniere deformity. J Hand Surg Am. 2011;36(1):139e142. 9. Benjamin M, Kaiser E, Milz S. Structure-function relationships in tendons: a review. J Anat. 2008;212(3):211e228. 10. Benjamin M, Ralphs JR. Fibrocartilage in tendons and ligaments—an adaptation to compressive load. J Anat. 1998;193(Pt 4):481e494.
r
Vol. 39, October 2014
Restoration of the Central Slip in Congenital Form of Boutonniere Deformity: Case Report Jong-Pil Kim, MD, Jai-Hyang Go, MD, Chang-Hwan Hwang, MD, Won-Jeong Shin, MS We present a case of a congenital form of a boutonniere deformity involving both little fingers with a poorly differentiated extensor mechanism and the absence of the tendinous attachment on the dorsal aspect of the middle phalanx. This complex deformity was evaluated histologically followed by successful reconstruction of the central slip. (J Hand Surg Am. 2014;39(10):1978e1981. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Key words Congenital deformity, boutonniere deformity, extensor mechanism, reconstruction.
B
OUTONNIERE DEFORMITY IS A RARE congenital disorder. It has been frequently confused with other flexion deformities such as congenital trigger digits or camptodactyly.1e3 Although the pathological features vary, attenuation of the central slip without disruption at its insertion has been noted.3,4 We present a case of a congenital boutonniere deformity in both little fingers with a poorly differentiated extensor mechanism and the absence of tendinous fixation of the central slip on the dorsal aspect of the middle phalanx. The proximal interphalangeal joint maintained a flexed position without volar subluxation of the lateral bands, which contradicted the usual chronic pathological condition. The rudimentary tissue of the central slip was examined histologically at its insertion, followed by successful reconstruction of the extensor mechanism. This was performed by dividing the conjoined tendon into
From the Department of Orthopedic Surgery, Department of Kinesiology and Medical Science, and Department of Pathology, Dankook University College of Medicine, Cheonan, Korea. Received for publication February 18, 2014; accepted in revised form May 22, 2014. The authors acknowledge Dr. Kyung Joon Lee for his effort in manuscript. Supported by the research fund of Dankook University in 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Jong-Pil Kim, MD, Department of Orthopedic Surgery, Dankook University College of Medicine, 359 Manghyangro, Dongnam-gu, Cheonan 330-715, Korea; e-mail: [email protected]. 0363-5023/14/3910-0013$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2014.05.030
1978
r
Ó 2014 ASSH
r
Published by Elsevier, Inc. All rights reserved.
3 slips and fixing the central slip to the base of the middle phalanx. The patient was informed that data from the case would be submitted for publication and gave consent. CASE REPORT A 26-year-old man presented with the inability to extend both little fingers, which was first noticed in early childhood. He denied any history of local trauma or a family history of a similar deformity. Systemic conditions possibly related to the deformity, including rheumatoid arthritis, neuromuscular disorders, connective tissue disease, or other skeletal deformities, were not noted. The patient had a 60 extension lag of the proximal interphalangeal joint and a 30 hyperextension of the distal interphalangeal joint on his left little finger during active finger extension. The little finger had full active flexion (Fig. 1). The same problem was noted in his right little finger in a milder form (30 extension lag of the proximal interphalangeal joint and 25 hyperextension of the distal interphalangeal joint). Digital neurovascular and radiographic examinations were normal. A diagnosis of bilateral congenital boutonniere deformity was made. At surgery, a curvilinear incision was made over the dorsum of the digit from the proximal phalanx to the middle phalanx on the left little finger. The extensor mechanism seemed to be constituted of one conjoined tendon without discrete separation into a central slip and 2 lateral bands over the proximal
CONGENITAL BOUTONNIERE DEFORMITY
1979
FIGURE 1: Preoperative photographs of the hands, showing boutonniere deformity in both little fingers.
FIGURE 3: Schematic illustrations of central slip reconstruction.
not noted. Splitting of the extensor tendon over the proximal interphalangeal joint revealed that rudimentary tissue was present at the dorsal aspect of the middle phalanx instead of a normal insertion of the central slip (Fig. 2). Lack of volar subluxation of the lateral bands without static contracture of the proximal interphalangeal joint suggested a loss of balance between the extensor and the flexors acting over the proximal interphalangeal joint during active finger extension on account of the extensor. The deformity was corrected by reconstructing the extensor mechanism, which was modified from techniques by Urbaniak and Hayes5 and Slesarenko et al.6 The central tendon flap was defined and elevated, dividing the conjoined tendon longitudinally into 3 slips. The central slip was advanced and sutured into the base of the middle phalanx using a suture anchor. The tendon slip was secured at the anatomical insertion of the central slip and was then additionally sutured to the elevated lateral slips with a nonabsorbable
FIGURE 2: Intraoperative photographs of the abnormal extensor mechanism over the proximal interphalangeal joint of the left little finger. A The extensor mechanism was composed of one conjoined tendon without development into 3 slips, which resulted in absence of the triangular ligament. B Splitting of the tendon demonstrated rudimentary insertion of central portion (asterisk).
interphalangeal joint (Fig. 2). This abnormal configuration of the extensor mechanism continued to its insertion, which may have led to failure of triangular ligament development. Furthermore, actual contracture of the transverse retinacular ligament was J Hand Surg Am.
r
Vol. 39, October 2014
1980
CONGENITAL BOUTONNIERE DEFORMITY
4-0 suture after the proximal interphalangeal joint was temporarily fixed in full extension using a Kirschner wire across the joint (Fig. 3). The same procedure was applied to the right little finger because it displayed the same findings intraoperatively. The fingers were immobilized with orthoses for 4 weeks, followed by a rehabilitation program after removal of the Kirschner wires. At the 22-month follow-up, the patient showed excellent finger motion with no residual deformity in his left hand and minimal extension lag at the proximal interphalangeal joint in his right hand. The histopathological assessment revealed myxoid degeneration with chondroid metaplasia of the rudimentary tissue at distal insertion of the central slip.
hood formed by the interosseous tendon and the lumbrical tendon, which transmit their force via the lateral bands to the distal phalanx, were not verified in this case. Furthermore, the lateral bands did not slip anterior to the axis of rotation of the proximal interphalangeal joint because they formed one conjoined tendon without developing into separate slips over the joint. Therefore, we speculate that hyperextension of the distal interphalangeal joint during extension was mainly caused by pull of the long extensor tendon rather than by pull of the intrinsic muscles or contracture of the oblique retinacular ligament. The flexion deformity of the proximal interphalangeal joint was created by the relatively stronger flexor digitorum superficialis, which becomes the dominant muscle in cases of a disrupted central slip.8 Histological changes in the remnant tissue at the tendon insertion site might be explained by the concept that histological characteristics can present in various forms on the gliding tendon, which usually indicates long tendons wrapped by a bony or fibrous pulley warping their straight direction.9 In our view, chondroid metaplasia of the remnant tissue underneath the conjoined tendon might occur due to gradient forces of the conjoined tendon, which is consistent with a previous report that the side of the tendon facing the source of compression is usually fibrocartilaginous.10 Various surgical procedures, including reattachment or reconstruction of the central slip, distal extensor tenotomy, tendon graft, and reconstruction of the transverse retinacular ligament, have been suggested for treating a chronic boutonniere deformity. Considering that passive extension of the proximal interphalangeal joint was not affected despite this unusual congenital deformity, the present case was treated by reconstructing the central slip, which was modified from techniques described by previous investigators.5,6 Our procedure consisted of elevating the central portion from the conjoined tendon, which may represent the central slip in a normal extensor mechanism, and securing it into the anatomic insertion of the central slip without additional reconstruction or release of the coordinating structures. Although this case does not represent a classic form, it extends our understanding of congenital boutonniere deformity and suggests a reliable surgical option.
DISCUSSION A chronic boutonniere deformity is characterized by flexion of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint, which result from imbalance between the long extensor-intrinsic complex acting over the dorsal aspect of the proximal interphalangeal joint and the flexor tendon volarly, contributing to increased tension in the lateral bands as they slip volarward.5,7,8 Carneiro and Lauderdale3 reported 5 congenital boutonniere deformities caused by attenuation of the central slip. They speculated that the attenuation was caused by an accident rather than a formation disorder occurring during embryogenesis. Lin et al4 reported a bilateral congenital boutonniere deformity with laxity of the central slip and believed that attenuation of the central slip occurred due to a developmental error in formation of the tendon and was aggravated by relatively powerful flexor tendons. Our case revealed a trifurcation failure of the extensor tendon over the proximal interphalangeal joint, which represented formation of one conjoined tendon without separation into one central slip and 2 lateral bands. A failure to develop bilateral lateral bands affects proper function of the transverse and oblique retinacular ligament, which control movement of the lateral bands either in flexion or extension of the proximal interphalangeal joint.7 Consequently, considering that deficiency of the structures coordinating extension of the finger mainly contributed to formation of the deformity in the present case, we postulate that a congenital form of boutonniere deformity represents various embryonic developmental failures. In contrast to a chronic traumatic boutonniere deformity, the thickened free margins of the extensor J Hand Surg Am.
REFERENCES 1. Koman LA, Toby EB, Poehling GG. Congenital flexion deformities of the proximal interphalangeal joint in children: a subgroup of camptodactyly. J Hand Surg Am. 1990;15(4):582e586.
r
Vol. 39, October 2014
CONGENITAL BOUTONNIERE DEFORMITY
2. Tsuge K. Congenital aplasia or hypoplasia of the finger extensors. Hand. 1975;7(1):15e21. 3. Carneiro RS. Congenital attenuation of the extensor tendon central slip. J Hand Surg Am. 1993;18(6):1004e1007. 4. Lin SC, Chiu HY. A nonexcision plication method for treatment of bilateral congenital boutonniere deformity: a preoperative biomechanical calculation. Plast Reconstr Surg. 2004;113(6): 1742e1745. 5. Urbaniak JR, Hayes MG. Chronic boutonniere deformity—an anatomic reconstruction. J Hand Surg Am. 1981;6(4): 379e383.
J Hand Surg Am.
1981
6. Slesarenko YA, Hurst LC, Mai K. Suture anchor technique for anatomic reconstruction in chronic boutonniere deformity. Tech Hand Up Extrem Surg. 2005;9(3):172e174. 7. Souter WA. The problem of boutonniere deformity. Clin Orthop Relat Res. 1974;104:116e133. 8. To P, Watson JT. Boutonniere deformity. J Hand Surg Am. 2011;36(1):139e142. 9. Benjamin M, Kaiser E, Milz S. Structure-function relationships in tendons: a review. J Anat. 2008;212(3):211e228. 10. Benjamin M, Ralphs JR. Fibrocartilage in tendons and ligaments—an adaptation to compressive load. J Anat. 1998;193(Pt 4):481e494.
r
Vol. 39, October 2014