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The management of trigger thumb in children
The management of trigger thumb in children Trigger thumb in children is an uncommon condition. We reviewed 41 patients with 53 trigger thumbs. Although the current accepted approach to the treatment of congenital trigger thumbs is a prolonged period of observation, our findings indicate that all of our patients eventually required surgic al release of the flexor pollicis longus tendon. Waiting 3 years before a surgical release was done did not affect the surgical result. (J IIAr-;n SURG 1991;16A:944-7.)
Errol Ger, MD, Paul Kupcha, MD, Wilmington, Del., and Dana Ger, Durham, N.C .
Trigger thumb in children is a relatively uncommon condition. The incidence has not been previously reported in the English-language literature and little information has been published on this condition during the past 10 years. The diagnosis of trigger thumb in the newborn infant may be delayed becaus e of the characteristic flexion attitud e of the thumb. This flexion posturing is normal until the age of 3 months when the child begin s to hold the thumb out of the palm . The frequent omission of routine thumb examination in the neonate may delay detection of this deform ity. In addition the demands placed on an infant's thumb arc minor, thus the functional abnormalities may go unnoticed. When grasping activities do occur in the child with a trigger thumb, disability may be minimal becau se of metacarpophalangeal and carpometacarpal joint compensation. The differential diagnosis of trigger thumb in childhood may include congenital clasped thumb, spastic thumb in palm , arthrogryposis, and other clutched thumb abnormalities. I, 2 . The usual position is one of interphalangeal joint flexion , although locked extension has been reported.' Physical examination with close observation of active and passive range of motion, along with the presence of a palpable nodule over the metacarpophalangeal joint,
From the Department of Orthopaedic Surgery, A. I. duPont Institute, Wilmington, Del. Received for publication May 3, 1990; accepted in revised form Jan. is, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Errol Ger, MD, A. I. duPont Institute, Rockland Rd. , P.O. Box 269, Wilmington, DE 19899.
3/1128370
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TilE JOURNAL OF HAND SURGERY
supports the diagnosis. The nodule, usually located over the metacarpophalangeal joint, may be tender.' Pathologic changes in the flexor pollicis longus tendon as the primary lesion were reported by Fahey and Bollinger.' Histologically they found collagenous degeneration and synovial proliferation disrupting normal gliding of the tendon through the A-I pulley. Others have reported A-I pulley changes as the primary pathology of this condition.?" Some trigger thumbs have resolved spont aneously. In their classic paper on trigger thumbs in children , Dinham and Meggitt? recommend the following: (1) observational management for 12 months in those patients diagnosed at birth. Spontaneous resolution was noted to occur in 30% of these patients on a retrospective review; (2) 6 month s' observation for patients with a diagnosis between ages 6 month s and 30 month s; and (3) surgical release for children with a diagnosis at age 3 years or more . ' In contrast, most earlier reports did not recommend a trial of observation and/or splinting. Jahss? concluded that the only treatment is surgical. He believed that stretching and splinting were prone to cause pathologic metacarpophalangeal joint hyperextension. Likewise, in 1942 Zadek" agreed that the only treatment was operative. In a review of 12 patients evaluated by Sprecher," all had surgery. Fahey and Bollinger' and White and Jenson' also echo this approach. The purpose of this retrospective review was to evaluate the prognosis for spontaneous resolution of trigger thumb s in children.
Materials and methods Between 1959 and 1989,41 patients with 53 thumbs involved were identified with trigger thumb of childhood . The diagnosis was made at the initial outpatient visit. Twelve cases were bilateral and 29 were unilateral. The right thumb was singly involved in 31 % and
Vol. 1M, No.5 September 1991
Trigger thumb ill children
945
-c.
Fig. 2. The A I pulley is incised after the digital nerves are identified. The flexor tendon is freed.
Results Fig. 1. The longitudinal incision is placed across the metacarpophalangeal crease of the thumb.
the left thumb was singly involved in 38% of patients. Only two patients could be identified who had a sibling or first-degree relative with a trigger thumb. The age range at diagnosis was birth to 12 years. Thirteen patients, or 30%, had diagnosis before 6 months of age, II of these at birth. Twenty-eight patients, or 70%, had diagnosis after 6 months of age. Associated diagnoses observed in 24% of the patients included femoral neck anteversion, scoliosis, genu varurn, internal tibial torsion, congenital vertical talus, metatarsus adductus, and Blount's disease of the tibia. All operations were done with the patient under general anesthesia except for one under local anesthesia at the parents' request. An above elbow tourniquet was used in all patients . In this study, sex distribution was 20 females and 21 males, not significantly different from previous reports. 6
We separated our patients into two groups. Group I patients were those patients with a diagnosis before 6 months. Group II patients had diagnosis after 6 months of age. Group I. This group consisted of 13 patients. Ten were male and 3 were female. Six of these 13 had bilateral trigger thumbs. The period of observation before surgical release averaged 44 months, a range from 9 to 139 months. Only one patient with diagnosis at birth had surgery performed before the 12-month period of observation as recommended by Dinham. Another patient in this group, with diagnosis at 5 months, also had surgery before the 12-months observation. None of these thumbs had resolution without surgery. All patients had A-I pulley division in the involved thumb(s). Group II. Group II consisted of28 patients in whom a diagnosis was made after 6 months of age. The average age at diagnosis was 42 months. The age range was 10 to 148 months. Eleven were male and 17 were female. Six (21%) had bilateral involvement. No patients in this group had spontaneous resolution.
946
Ger et al.
Operative treatment A longitudinal incision has been used exclusively since 1979. The incision is placed at 90 degrees to the palmar metacarpophalangeal joint crease of the thumb (Fig. 1). Before 1979 a transverse incision had been used. We recommend this longitudinal incision because it is the safest with regard to potential digital ner ve injury . The inherent safety afforded by this incision, which parallels the general course of the digital nerve , is obvious. The superficial position of these digital nerves make digital nerve transection a potential complication. Postoperative scarring or contracture has not been a problem. Only the skin is incised with the knife and then the subcutaneous tissue is bluntly dissected. The digital nerves are identified and retracted clear of the A-I pulIey. The pulley is then released (Fig. 2). The flexor polIicis longus is delivered out of the wound, over a hemostat, and alIowed to retract. A fulI range of passive motion is then verified at the interphalangeal joint. The incision is closed with interrupted absorbable sutures. A soft dressing is employed until the patient returns for foIlow-up 3 days later. Discussion A. I. duPont Institute is a major regional referral center for pediatric orthopedics. During the years of this study, approximately 90,000 patients were seen at our hosp ital. The incidence of trigger thumb at our hospital would, therefore, be approximately 1 in 2,000. Although this is not a random sample of patients, this certainly speaks for the rarity of this condition. Flatt' reported an incidence of 2.2% for this condition in a survey of 2159 patients with congenital hand deformities . The current accepted approach to trigger thumb of childhood is an initial period of observation. The guidelines established by Dinham and Meggitt? are the most widely accepted. In their classic paper, they note a 30% chanc e of spontaneous resolution of the trigger thumb in the patient with diagnosis at birth if the child is observed for 12 months . They also contend that in approximately 7% of those patients who had diagnosis some time later than birth, but before the age of 3 years, the condition will resolve spontaneously if watched for 6 months or more . This incidence of spontaneous correction contrasts sharply with our findings in both groups . We found that none of our II patients (17 thumbs) with diagnosis before 6 months of age resol ved without surgery despite our average of 40 months of conservative therapy
The Journal of HAND SURGERY
(range,3 to 151 months). We are unable to explain the difference between the results in the article by Dinham and Meggitt and this review. Instead, our findings confirm the earlier observations of others." 5 . 7-9 Of the 29 thumbs in 24 patients diagnosed some time after birth , there was no spontaneous resolution of the trigger thumb deformity. Nine had been watched for the recommended 6 months as suggested by Dinham and Meggitt. None of our patients who had surgery showed any residual flexion contracture of the thumb when examined I year later. However, those children who had surgery after the age of 3 years took many months to correct the contracture. Physical therapy was not used. Although observation may playa benign role in the management of patients less than 3 years old, based on our results we cannot recommend a trial period of observation. The patient's care provider should be educated as to the poor prognosis for spontaneous resolution and suggest operative treatment. Obviously this is an elective procedure and can be done when the child is weIl and thriving and the anesthesiologist believes that it is safe to proceed with surgery. As noted in other reports on trigger thumb of childhood, we found a disproportionate increa se of this deformity being bilateral when diagnosed at birth. Fiftyfour percent of the patients had bilateral involvement at birth compared with 20% of alI others. This is similar to Dinham and Meggitt's findings of 58% and 28%, respectively. It is uncertain if this increased frequency reflects an actual increa sed incidence or merely represents an observational bias. Perhaps the condition is more readily recognized at an earlier age simply becau se the child has two deformities instead of one. In this series, we were able to identify 10 patients (24%) who had an apparently unassociated diagnosis. No patient had an associated congenital hand anomaly. AIl 10 patients had an associated lower extremity or spine diagnosis. To our knowledge, this association with lower extremity abnormalities has not been previously reported. It is quite possible that this finding reflects the skewed patient population that is treated at a tertiary referral center such as the A. I. duPont Institute. This high association of disorders should, howe ver, comp el the examining physician to rule out addition al pathology when evaluating the patient with trigger thumb, with special attention being directed to detailed examination of the lower extremities.
Vol. 16A, No.5 September 1991
Trigger thumb ill children
REFERENCES I. Flatt AE. The care of congenital hand anomalies. SI. Louis : CV Mosby, 1977:59-60. 2. Kelikian H. Congenital deformities of the hand and forearm . Philadelphia: WB Saunders, 1974:558-63. 3. Fahey 11, Bollinger JA. Trigger fingers in adult s and children . J Bone Joint Surg 1954;36A:1200-18. 4 . Grob M, Stockman M. Stenosing tenov aginosis: a typical affection in early childhood. Helv Paedi atr Acta 1951; 6:112-8.
5. White AW, Jenson WE. Trigger thumb in infants. J Dis Children 1953;85:141-5. 6. Dinham JM, Meggitt BF. Trigger thumb s in children. J Bone Joint Surg 1974;56B :153-5 . 7. Jahss SA. Trigger finger in children. JAMA 1936; 107:1463-4. 8. Zadek I. Stenosing tenovaginitis of the thumb in infants . J Bone Joint Surg 1942;24:326-8. 9. Sprecher EE . Trigger thumb in infants . J Bone Joint Surg 1949;31A:672.
Correction of constriction rings A refinement in the correction of deep and shallow constriction rings, in which subcutaneous fat and fascial flaps are advanced into the defect to prevent recurrent contour deformities, is presented. A straight-line dorsal closure is preferred, with Z-plasties placed along the side of the digits, forearm, or arm. Long-term follow-up is presented in 58 patients with 116constriction rings corrected by either traditional serial Z.plasties of skin (n 61 rings) or this new method of contour correction (II 55 rings). Specific correction of soft tissue is recommended when tissue is available. (J HA1'iD SURG 1991;I6A:947-53.)
=
=
Joseph Upton, MD, and Cissy Tan, MD, Boston, Mass .
The constriction ring syndrome and its etiology have been an intriguing medical problem that has aroused the curiosity and imagination of many investigators. The speculative literature on the etiology of these rings and associated limb and craniofacial anomalies far exceeds information describing methods of correction of the deep annular bands, distal lymphedema, and the wide variety of digital malformations.!"
From the Division of Plastic and Reconstructive Surgery, Department of Surgery, Harvard Medical School, Children's Hospital and Beth Israel Hospital. Boston, Mass. Presented at the American Society for Surgery of the Hand, Seplember 15, 1988, Baltimore, Md. Received for publication March 2, 1989; accepted in revised form Jan . 15, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article . Reprint requests: Joseph Upton, MD, 830 Boylston St., Suite 212 , Chestnut Hill. MA 02167 .
3/1/2906t
The morphologic configurations of the limb anomalies vary tremendously. No two hands are alike. The anatomic presentation may involve congenital amputations, constriction rings, all degrees of hypoplasia, and distal coalescence of digits (acrosyndactyly). In his classic description, Patterson" wrote that to be included in this syndrome a patient must have two of the following anomalies: (I) a simple con striction ring. (2) a constriction ring with distal deformity with or without lymphedema, (3) a ring constriction with fusion of distal parts (acrosyndactyly), or (4) an intrauterine amputation . Any digit or extremity can be involved, and asymmetrical involvement is the rule. The rings may be deep or shallow and extend completely or incompletely around the circumference of a limb or digit. Strands of amnion can occasionally be seen within the ring at birth (Fig. 1). The most severe manifestation of a deep ring is a congenital amputation. Correction of these rings, which create a soft tissue deformity, is the subject of this brief report. It is based on long-term observations of the contour deformities that result from simple Z-plasty correctlon.r"
THE JOURNAL OF HAND SURGERY
947
Errol Ger, MD, Paul Kupcha, MD, Wilmington, Del., and Dana Ger, Durham, N.C .
Trigger thumb in children is a relatively uncommon condition. The incidence has not been previously reported in the English-language literature and little information has been published on this condition during the past 10 years. The diagnosis of trigger thumb in the newborn infant may be delayed becaus e of the characteristic flexion attitud e of the thumb. This flexion posturing is normal until the age of 3 months when the child begin s to hold the thumb out of the palm . The frequent omission of routine thumb examination in the neonate may delay detection of this deform ity. In addition the demands placed on an infant's thumb arc minor, thus the functional abnormalities may go unnoticed. When grasping activities do occur in the child with a trigger thumb, disability may be minimal becau se of metacarpophalangeal and carpometacarpal joint compensation. The differential diagnosis of trigger thumb in childhood may include congenital clasped thumb, spastic thumb in palm , arthrogryposis, and other clutched thumb abnormalities. I, 2 . The usual position is one of interphalangeal joint flexion , although locked extension has been reported.' Physical examination with close observation of active and passive range of motion, along with the presence of a palpable nodule over the metacarpophalangeal joint,
From the Department of Orthopaedic Surgery, A. I. duPont Institute, Wilmington, Del. Received for publication May 3, 1990; accepted in revised form Jan. is, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Errol Ger, MD, A. I. duPont Institute, Rockland Rd. , P.O. Box 269, Wilmington, DE 19899.
3/1128370
944
TilE JOURNAL OF HAND SURGERY
supports the diagnosis. The nodule, usually located over the metacarpophalangeal joint, may be tender.' Pathologic changes in the flexor pollicis longus tendon as the primary lesion were reported by Fahey and Bollinger.' Histologically they found collagenous degeneration and synovial proliferation disrupting normal gliding of the tendon through the A-I pulley. Others have reported A-I pulley changes as the primary pathology of this condition.?" Some trigger thumbs have resolved spont aneously. In their classic paper on trigger thumbs in children , Dinham and Meggitt? recommend the following: (1) observational management for 12 months in those patients diagnosed at birth. Spontaneous resolution was noted to occur in 30% of these patients on a retrospective review; (2) 6 month s' observation for patients with a diagnosis between ages 6 month s and 30 month s; and (3) surgical release for children with a diagnosis at age 3 years or more . ' In contrast, most earlier reports did not recommend a trial of observation and/or splinting. Jahss? concluded that the only treatment is surgical. He believed that stretching and splinting were prone to cause pathologic metacarpophalangeal joint hyperextension. Likewise, in 1942 Zadek" agreed that the only treatment was operative. In a review of 12 patients evaluated by Sprecher," all had surgery. Fahey and Bollinger' and White and Jenson' also echo this approach. The purpose of this retrospective review was to evaluate the prognosis for spontaneous resolution of trigger thumb s in children.
Materials and methods Between 1959 and 1989,41 patients with 53 thumbs involved were identified with trigger thumb of childhood . The diagnosis was made at the initial outpatient visit. Twelve cases were bilateral and 29 were unilateral. The right thumb was singly involved in 31 % and
Vol. 1M, No.5 September 1991
Trigger thumb ill children
945
-c.
Fig. 2. The A I pulley is incised after the digital nerves are identified. The flexor tendon is freed.
Results Fig. 1. The longitudinal incision is placed across the metacarpophalangeal crease of the thumb.
the left thumb was singly involved in 38% of patients. Only two patients could be identified who had a sibling or first-degree relative with a trigger thumb. The age range at diagnosis was birth to 12 years. Thirteen patients, or 30%, had diagnosis before 6 months of age, II of these at birth. Twenty-eight patients, or 70%, had diagnosis after 6 months of age. Associated diagnoses observed in 24% of the patients included femoral neck anteversion, scoliosis, genu varurn, internal tibial torsion, congenital vertical talus, metatarsus adductus, and Blount's disease of the tibia. All operations were done with the patient under general anesthesia except for one under local anesthesia at the parents' request. An above elbow tourniquet was used in all patients . In this study, sex distribution was 20 females and 21 males, not significantly different from previous reports. 6
We separated our patients into two groups. Group I patients were those patients with a diagnosis before 6 months. Group II patients had diagnosis after 6 months of age. Group I. This group consisted of 13 patients. Ten were male and 3 were female. Six of these 13 had bilateral trigger thumbs. The period of observation before surgical release averaged 44 months, a range from 9 to 139 months. Only one patient with diagnosis at birth had surgery performed before the 12-month period of observation as recommended by Dinham. Another patient in this group, with diagnosis at 5 months, also had surgery before the 12-months observation. None of these thumbs had resolution without surgery. All patients had A-I pulley division in the involved thumb(s). Group II. Group II consisted of28 patients in whom a diagnosis was made after 6 months of age. The average age at diagnosis was 42 months. The age range was 10 to 148 months. Eleven were male and 17 were female. Six (21%) had bilateral involvement. No patients in this group had spontaneous resolution.
946
Ger et al.
Operative treatment A longitudinal incision has been used exclusively since 1979. The incision is placed at 90 degrees to the palmar metacarpophalangeal joint crease of the thumb (Fig. 1). Before 1979 a transverse incision had been used. We recommend this longitudinal incision because it is the safest with regard to potential digital ner ve injury . The inherent safety afforded by this incision, which parallels the general course of the digital nerve , is obvious. The superficial position of these digital nerves make digital nerve transection a potential complication. Postoperative scarring or contracture has not been a problem. Only the skin is incised with the knife and then the subcutaneous tissue is bluntly dissected. The digital nerves are identified and retracted clear of the A-I pulIey. The pulley is then released (Fig. 2). The flexor polIicis longus is delivered out of the wound, over a hemostat, and alIowed to retract. A fulI range of passive motion is then verified at the interphalangeal joint. The incision is closed with interrupted absorbable sutures. A soft dressing is employed until the patient returns for foIlow-up 3 days later. Discussion A. I. duPont Institute is a major regional referral center for pediatric orthopedics. During the years of this study, approximately 90,000 patients were seen at our hosp ital. The incidence of trigger thumb at our hospital would, therefore, be approximately 1 in 2,000. Although this is not a random sample of patients, this certainly speaks for the rarity of this condition. Flatt' reported an incidence of 2.2% for this condition in a survey of 2159 patients with congenital hand deformities . The current accepted approach to trigger thumb of childhood is an initial period of observation. The guidelines established by Dinham and Meggitt? are the most widely accepted. In their classic paper, they note a 30% chanc e of spontaneous resolution of the trigger thumb in the patient with diagnosis at birth if the child is observed for 12 months . They also contend that in approximately 7% of those patients who had diagnosis some time later than birth, but before the age of 3 years, the condition will resolve spontaneously if watched for 6 months or more . This incidence of spontaneous correction contrasts sharply with our findings in both groups . We found that none of our II patients (17 thumbs) with diagnosis before 6 months of age resol ved without surgery despite our average of 40 months of conservative therapy
The Journal of HAND SURGERY
(range,3 to 151 months). We are unable to explain the difference between the results in the article by Dinham and Meggitt and this review. Instead, our findings confirm the earlier observations of others." 5 . 7-9 Of the 29 thumbs in 24 patients diagnosed some time after birth , there was no spontaneous resolution of the trigger thumb deformity. Nine had been watched for the recommended 6 months as suggested by Dinham and Meggitt. None of our patients who had surgery showed any residual flexion contracture of the thumb when examined I year later. However, those children who had surgery after the age of 3 years took many months to correct the contracture. Physical therapy was not used. Although observation may playa benign role in the management of patients less than 3 years old, based on our results we cannot recommend a trial period of observation. The patient's care provider should be educated as to the poor prognosis for spontaneous resolution and suggest operative treatment. Obviously this is an elective procedure and can be done when the child is weIl and thriving and the anesthesiologist believes that it is safe to proceed with surgery. As noted in other reports on trigger thumb of childhood, we found a disproportionate increa se of this deformity being bilateral when diagnosed at birth. Fiftyfour percent of the patients had bilateral involvement at birth compared with 20% of alI others. This is similar to Dinham and Meggitt's findings of 58% and 28%, respectively. It is uncertain if this increased frequency reflects an actual increa sed incidence or merely represents an observational bias. Perhaps the condition is more readily recognized at an earlier age simply becau se the child has two deformities instead of one. In this series, we were able to identify 10 patients (24%) who had an apparently unassociated diagnosis. No patient had an associated congenital hand anomaly. AIl 10 patients had an associated lower extremity or spine diagnosis. To our knowledge, this association with lower extremity abnormalities has not been previously reported. It is quite possible that this finding reflects the skewed patient population that is treated at a tertiary referral center such as the A. I. duPont Institute. This high association of disorders should, howe ver, comp el the examining physician to rule out addition al pathology when evaluating the patient with trigger thumb, with special attention being directed to detailed examination of the lower extremities.
Vol. 16A, No.5 September 1991
Trigger thumb ill children
REFERENCES I. Flatt AE. The care of congenital hand anomalies. SI. Louis : CV Mosby, 1977:59-60. 2. Kelikian H. Congenital deformities of the hand and forearm . Philadelphia: WB Saunders, 1974:558-63. 3. Fahey 11, Bollinger JA. Trigger fingers in adult s and children . J Bone Joint Surg 1954;36A:1200-18. 4 . Grob M, Stockman M. Stenosing tenov aginosis: a typical affection in early childhood. Helv Paedi atr Acta 1951; 6:112-8.
5. White AW, Jenson WE. Trigger thumb in infants. J Dis Children 1953;85:141-5. 6. Dinham JM, Meggitt BF. Trigger thumb s in children. J Bone Joint Surg 1974;56B :153-5 . 7. Jahss SA. Trigger finger in children. JAMA 1936; 107:1463-4. 8. Zadek I. Stenosing tenovaginitis of the thumb in infants . J Bone Joint Surg 1942;24:326-8. 9. Sprecher EE . Trigger thumb in infants . J Bone Joint Surg 1949;31A:672.
Correction of constriction rings A refinement in the correction of deep and shallow constriction rings, in which subcutaneous fat and fascial flaps are advanced into the defect to prevent recurrent contour deformities, is presented. A straight-line dorsal closure is preferred, with Z-plasties placed along the side of the digits, forearm, or arm. Long-term follow-up is presented in 58 patients with 116constriction rings corrected by either traditional serial Z.plasties of skin (n 61 rings) or this new method of contour correction (II 55 rings). Specific correction of soft tissue is recommended when tissue is available. (J HA1'iD SURG 1991;I6A:947-53.)
=
=
Joseph Upton, MD, and Cissy Tan, MD, Boston, Mass .
The constriction ring syndrome and its etiology have been an intriguing medical problem that has aroused the curiosity and imagination of many investigators. The speculative literature on the etiology of these rings and associated limb and craniofacial anomalies far exceeds information describing methods of correction of the deep annular bands, distal lymphedema, and the wide variety of digital malformations.!"
From the Division of Plastic and Reconstructive Surgery, Department of Surgery, Harvard Medical School, Children's Hospital and Beth Israel Hospital. Boston, Mass. Presented at the American Society for Surgery of the Hand, Seplember 15, 1988, Baltimore, Md. Received for publication March 2, 1989; accepted in revised form Jan . 15, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article . Reprint requests: Joseph Upton, MD, 830 Boylston St., Suite 212 , Chestnut Hill. MA 02167 .
3/1/2906t
The morphologic configurations of the limb anomalies vary tremendously. No two hands are alike. The anatomic presentation may involve congenital amputations, constriction rings, all degrees of hypoplasia, and distal coalescence of digits (acrosyndactyly). In his classic description, Patterson" wrote that to be included in this syndrome a patient must have two of the following anomalies: (I) a simple con striction ring. (2) a constriction ring with distal deformity with or without lymphedema, (3) a ring constriction with fusion of distal parts (acrosyndactyly), or (4) an intrauterine amputation . Any digit or extremity can be involved, and asymmetrical involvement is the rule. The rings may be deep or shallow and extend completely or incompletely around the circumference of a limb or digit. Strands of amnion can occasionally be seen within the ring at birth (Fig. 1). The most severe manifestation of a deep ring is a congenital amputation. Correction of these rings, which create a soft tissue deformity, is the subject of this brief report. It is based on long-term observations of the contour deformities that result from simple Z-plasty correctlon.r"
THE JOURNAL OF HAND SURGERY
947