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Congenital radioulnar synostosis
THE JOURNAL OF
HAND SURGERY
NOVEMBER 1983 VOLUME 8,
NUMBER 6
Official journal AMERICAN SOCIETY FUR SURGERY OF THE HAND
ORIGINAL COMMUNICATIONS Congenital radioulnar synostosis Congenital radioulnar synostosis can be severely disabling, especially if it is bilateral or if severe hyperpronation exists. Functionally, patients with severe deformity have trouble getting a cup to the mouth, using eating utensils, or accepting objects in an open palm. Of 33 patients (17 bilateral and 7 unilateral) underwent derotational osteotomy, with the majority being performed through the synostosis held with, an intramedullary wire and secondary transfixing device. There were eight complications, four involving neurovascular compromise. In bilateral cases, the best end position appears to be 10% to 15% of pronation in the dominant extremity and neutral in the other. Eighty-two percent of the patients had good or excellent results. (J HAND SURG 9:829-38, 1983.)
Barry P. Simmons, M.D., William W. Southmayd, M.D., and Edward 1. Riseborough, M.D., Boston, Mass.
Congenital synostosis of the proximal radius and ulna is a rare malformation of the upper limb. The first anatomic description of this entity was given by Sandi fort in 1793. One hundred years later, Morrison described a clinical case and demonstrated the classical physical findings. 1 The use of x-rays since 1900 led to more individual case reports of this lesion. 2-14 Fahlstrom 'S15 exhaustive review in 1932 listed 195 patients. More recently, Green and MitaP6, 17 have reported fifteen cases. In all, there have been fewer than 250 cases reported to date. This study is based on an analysis of 33 patients with radioulnar synostosis treated at Children's Hospital Medical Center between the years 1949 and 1980. Any cases of proximal radioulnar crossed union following fracture were excluded from the series. IS From the Departments of Orthopedic Surgery, Harvard Medical School, Children's Hospital Medical Center, Brigham and Women's Hospital, Boston, Mass. Received for publication Feb. 18, 1982; accepted in revised form Nov. 9, 1982. Reprint requests to: Barry P. Simmons, M.D., Chief, Hand Surgery Service, Department of Orthopedic Surgery, Children's Hospital Medical Center, 300 Longwood Ave., Boston, MA 02115.
This paper compares the findings in our large series with those in the literature, examines the surgical alternatives and presents a long-term follow-up on selected operative cases.
Embryology During the embryonic period of fetal development the upper limb bud arises from the unsegmented body wall at 26 days of age. Growth and differentiation continue until 48 days, when all external characteristics of the adult limb are present. 19 The elbow is first discernible at 35 days. At this stage there are three connected cartilaginous anlage present destined to become the humerus, the radius, and the ulna. Soon thereafter longitudinal segmentation produces a separation of the distal radius and ulna, but for a time their proximal ends are united and share a common perichondrium. 20 Therefore, abnormal genetic or tetatogenic factors operating at this time would interrupt subsequent proximal radioulnar joint morphogenesis. Such interference with joint formation would allow for later ossification of the entire proximal cartilaginous model and produce complete bony synostosis. If joint development continued somewhat further before deve!THE JOURNAL OF HAND SURGERY
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Fig. 1. In bilateral cases with hyperpronation "backhanded" positioning is necessary to get objects to one's mouth.
opmental arrest occurred, this could logically lead to a smaller area of coalition and the presence of a rudimentary radial head. During this period of intrauterine development, the forearm is in a position midway between neutral and full pronation. Wilke surmised that "the position of pronation found in this deformity is therefore normal for the young embryo . "21 Hence, it would seem that failure of proximal radioulnar joint differentiation leaves the forearm forever in its fetal position. With the exception of one case,17 in all previous clinical cases the forearm has been fixed in this position.1 5. 21 Etiology. Although the etiology is unknown, there appears to be a genetic basis for this condition. Positive family histories have been reported ll • 12. 15,22 and it is seen in disorders such as acropolysyndactyly (Carpenter's syndrome), acrocephalosyndactyly (Apert's syndrome), arthrogryposis, and mandibulofacial dysostosisP More specific evidence for a genetic etiology is provided by noting its presence in nondysfunctional sex chromosomal abnormalities, especially Klinefelter's syndrome and its variants. 21, 26-28 Clinical factors Review of previous cases3, 13. 16, 17 produces a history and physical examination results consistent with our series as noted below. Radiologically findings in our patients' were simihr to those reported8 , 29 and are consistent with a spectn,m of length of the fusion mass as opposed to an attempt to differentiate "types" by Wilkie .21 Early surgical treatment was aimed at restoring mo-
tion to the affected forearm. This has included simple division of the bony bridge tl or resection of the synostotic proximal radius, saving the bicepital tuberosity with l • 4. :!1 and without 30 muscle interposition and with division of the interosseous membrane. 12 None of these procedures restored motion. Kelekian and Doumanian 2fi devised a metallic swivel to be put in the intramedullary canal of the radius between the supinator and pronator teres. This was used in conjunction with resection of the distal ulna and transfer of the flexor carpi ulnaris to the dorsum of the hand to help restore supination . They reported good results in posttraumatic , proximal radioulnar synostosis. Tachdjian, 32 however, reports its use in congenital radioulnar synostosis with disappointing results presumably due to contracture of the nonosseous forearm structures. As a result of these experiences, several authors concluded that there was no surgical treatment for this problem .4 . 6. 22. 2H A more practical solution to the problem was first offered by Sever at Children's Hospital in Boston in 1919. 33 He thought that the functionally deficient, pronated forearm should be fixed in a new, more useful position. He pointed out that one could pronate a forearm fixed neutrally or in supination by abduction and internal rotation of the shoulder. However, the chest wall and trunk block any attempt to use the shoulder to supinate a forearm fixed in pronation . His operative technique involved resection of a Y2-inch segment of the proximal radial shaft just distal to the synostosis. He then rotated the forearm around the ulna into supination and held this position in a cast . This apparently gave excellent functional results in a single patient. The usefulness of this concept was reinforced 4 years later by Gibson 34 who stated that' 'full supination is certainly not the optimum position; full pronation is not so good as the midposition. An osteotomy to bring about this change of position from full to semipronation is probably justified in some people." A subsequent report by Green and MitaP6. 17 included 15 patients with this disorder and they found that the grossly pronated forearm constituted a "severe functional and cosmetic handicap." They also recommended surgical de rotation of the forearm. Their goal in bilateral cases was to place one hand in 20° to 30° of supination and the other in 30° to 45° of pronation . The operative technique advocated was transverse osteotomy through the synostosis with the use of Kirschner wires for maintenance of position. Clinical series There were 33 patients with congenital radioulnar synostosis seen at Children's Hospital Medical Center during this 3 I-year time period. Charts and x-ray films
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Congenital radioliinar synostosis
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Fig. 2. Patients find (A) feeding themselves and (B) "accepting" objects such as coins awkward and difficult.
were reviewed on each child and physical examination was perfonned on the 24 patients available for followup. Of the 33 patients, 19 were boys and 14 were girls. Nineteen had bilateral involvement, with a sex ratio of II boys to 8 girls. Unilateral involvement occurred in 14 cases, with a sex ratio of 8 boys to 6 girls. Of these unilateral cases, 9 were the right ann and 5 were the left. There was a total of 52 affected foreanns in the 33 patients . The average age at which the affliction was noted by the parents was 21h years. The earliest recognition was at the first postnatal examination-the latest was in a unilateral case at the age of 10. Twelve cases were discovered before the age of I year. Functional complaints were specifically mentioned in the charts of 22 patients . They included: (1) difficulty in holding or using small objects such as spoons or pencils, (2) inability to dress themselves due to poor manipulative ability in dealing with belt buckles and buttons, (3) backhanded position in holding objects such as bottles or toys (Fig. I), (4) difficulty in feeding themselves (Fig. 2, A), (5) inability to accept small objects in their hands , (e.g., coins) (Fig. 2, B), and (6) difficulty competing in sports requiring upper extremity dexterity. These functional deficiencies were definitely more common in patients with bilateral involvement and in those with the more severe degrees of fixed
pronation. Cosmetic appearance was mentioned as a cause of concern, but usually only by the parents . Additional congenital anomalies were present in II of the 33 patients. The organ systems involved were the musculoskeletal, cardiovascular, thoracic, central nervous system, renal, and gastrointestinal. Specifically these included: Thumb . Aplasia (three cases), polydactyly, Streeter's dysplasia, hypoplasia Digits. Syndactyly (four cases) Carpus. Partial carpal coalition Cardiac . Tetralogy of Fallot, ventricular septal defect Thoracic. Hypoplasia of first and second ribs, hypoplasia of pectoral musculature Central nervous system . Microcephaly, hydrocephalus (two cases), encephalocele, mental retardation, slow developmental milestones, and right spastic hemiplegia Renal . Unilateral hypoplasia Gastrointestinal . Umbilical hernia A positive family history was present in only one instance. This was a male patient with bilateral involvement. His paternal grandmother and uncle both had similar afflictions. Two patients in the series with bilateral involvement each have children of their own, but none have synostosis. One child had chromosomal
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The Journal of HAND SURGERY
Fig. 3. Passive rotational hypermobility of the wrist was a universal finding . This is obviously an adaptive phenomenon to compensate for the absence of forearm rotation . analysis perfonned that revealed a nonnal female karyotype. Possible teratogenic factors included one case of first trimester rubella, which produced a severely defonned child who died within 1 year, and another case in which the mother used rectal suppositories containing cortisone in the first 6 weeks of pregnancy .
Physical examination Data on the carrying angle of the affected elbow was available in 22 patients. Assuming the nonnal carrying angle to be 15° to 20° of valgus, it was increased in 2 patients, nonnal in 5, and less than nonnal in 15. In those instances in which the extended elbow was in neutral or varus, there was no correlation with the presence or absence of a radial head .
Elbow extension was less than full in 22 of 30 patients on whom this infonnation was available. The average fixed flexion contracture was 16°, with a range from 5° to 30°. Six patients had full extension and two had hyperextension. Marked shortening of the fore ann occurred in four instances. Two had unilateral involvement with a length differential of 8 cm. The other two patients had bilateral involvement, but the shortening was readily apparent. In two of these patients the synostosis extended more than halfway down the foreann. In three other unilateral patients shortening was observed, but it did not exceed 2 cm. Rotational hypennobility of the wrist was unifonnly present in the affected extremities (Fig. 3). It was most prominent in children, but persisted into adulthood .
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Congenital radioulnar synostosis
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Fig. 4. Radiologically , a broad spectrum of synostosis is seen. A, Virtually total synostosis; B, shorter area of synostosis with radial head absent (most common); C, short synostosis with radial head present but subluxed; and D, deformed distal radioulnar and radiocarpal joints.
There was no increased mobility or instability in other planes of wrist motion . Atotal arc of rotation from 30° to 45° was the rule . Presumably this is due to ligamentous laxity secondary to continued rotational stress on the wrist in the absence of forearm rotation. None of the patients complained of wrist pain or stiffness. Positional data. Analysis of the fixed position of the forearms in these patients revealed 38% in less than 30° of pronation, 20% between 30° and 60°, and 42% fixed in more than 60° of pronation . Radiographic analysis Analysis of the x-ray films of these patients did not confirm the classical description of two distinct types of radioulnar synostosis as proposed by Wilkie. 2 Rather, there appears to be a spectrum of anatomic variation. This ranges from total synostosis (Fig. 4, A) with marked shortening of the entire forearm to progressively shorter areas of synostosis without the presence of a radial head (Fig . 4, B). Short synostosis often accompanies radial head presence (Fig . 4, C) , which finally gives way to synostotic absence and minor radial head deformity in a patient with a 45° arc of rotation on one side and synostosis with a radial head on the other. The longer synostotic areas showed continuity of can-
cellous bone throughout the coalition, while shorter synostoses had varying amounts of cortical bone centrally. The distal aspect of the synostosis was arcuate in shape. The presence of such a continuum of involvement- ranging from quite severe to almost normalconforms logically with the embryologic postulate of developmental arrest at varying stages of fetal maturation . Correlated with the physical examination results, the more extensive synostoses with radial head absence had a greater degree of fixed pronation . When present, the radial head is not always dislocated with respect to the capitellum . The proximal radial epiphysis appeared at the expected time and developed along a normal sequence. At the completion of growth, the radial heads had a normal concave configuration. When there was absence of the radial head, the capitellum seemed to have an abnormally globular appearance. Radial shaft bowing was common but varied in its severity. There was a uniform absence of proximal radial tapering at the level where the bicipital tuberosity is usually located. The distal radioulnar joint was clinically normal in most patients. In some there was mild hypoplasia of the distal ulna with subluxation radiologically. In two cases
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The Journal of HAND SURGERY
Fig. 5. Osteotomy through the synostosis held with an intramedullary pin was the most common, simplest procedure . A second "stabilizing" device may be used (crossed wire), but should be left accessible in case neurovascular compromise requires dederotation. In this patient a percutaneous pin was used through the distal fragment and secured in plaster.
the distal radius was grossly deranged with marked palmar and ulnar deviation of the articulating surface (Fig . 4,D) .
Indications for surgery The functional deficit associated with radioulnar synostosis is dependent on two main factors: (I) the obvious loss of forearm axial rotation, and (2) the position in which the forearm is fixed . With 60° or more of fixed pronation, the child has the serious function restrictions noted previously . Clearly, these patients benefit from having their forearms placed in a more functionally and cosmetically acceptable position. Logically , the dominant arm should be derotated first and we believe that it should be done before they start school to maximize their gain from surgery. Children whose forearms are fused in positions from neutral to 15° of pronation function very well; their only restrictions involve accepting objects in an open palm and performing very specific athletic activities such as pull-ups. Some have difficulty eating , but most are not markedly incapacitated by this degree of pronation. These children learn to function so well that surgery is unnecessary. For those patients that fall in between these clear extremes, one must carefully individualize the need for surgical intervention. Important factors in the decision are whether there is unilaterality or bilaterality of involvement and the results of careful history and physical examination that allow analysis of the child's functional capacity. If this capacity is severely limited , surgical correction should be advised .
Analysis of operative series There were 29 operations performed on 20 patients, eight of whom had unilateral involvement and 12 had
bilateral deformity . Of the surgical procedures performed , 22 involved derotation of the forearm; two were to correct ulnar deviation of the wrist and five were hand operations. Only one patient underwent derotation of both forearms. No effort to create motion was attempted in this series. Various techniques were used to achieve derotation of the forearm. In four patients, only the radius was osteotomized, with rotation of the distal radial segment around the ulna through the distal radioulnar joint. The shafts of the radius and ulna were osteotomized in two patients. In 16 forearms the osteotomy was created through the synostosis, with subsequent derotation of the distal forearm-hand unit. Seven of 14 patients with unilateral involvement underwent derotation as did 10 of 19 with bilateral affliction. The average age at the first osteotomy was 8 years, with a range from 21/2 to 171/2 years. The average initial position in the surgical patients was 82° of pronation, with a range from 45° to 120° of pronation. Only one forearm fixed in less than 60° of pronation had surgery . The average de rotation achieved with a single osteotomy was 67°, the least being 25° and the most 90°. Two children required two-stage de rotation and one had three operations on a single forearm moving from 120° of pronation to neutral. One patient had surgery on both forearms. The final position averaged 8° of pronation. Three patients were moved to a position of fixed supination: two of 15° and one of 20°. Of these, one patient had bilateral synostoses and two were unilateral. In this series internal fixation was achieved either by Kirschner wires, Steinmann pins, or Blount staples. In three cases no internal fixation was used. All patients subsequently spent from 6 to 24 weeks in a long arm cast. In every case but one the fixation devices were removed later.
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Operative procedure The most commonly performed procedure was, as suggested by Dr. William T. Green,16 an osteotomy through the synostosis (Fig. 5). The skin incision is placed along the subcutaneous border of the ulna. Deep fascia is opened longitudinally along the anconeus and the extensor carpi ulnaris. The synostosis is exposed by subperiosteal elevation dorsally and palmarly. The midportion of the synostosis is identified and osteotomized. A Steinmann pin is then placed down the intermedullary canal of the ulna across the osteotomy site to maintain axial alignment and the derotation is performed about this pivot point. Soft tissue resistance limits the degree to which the forearm may be derotated. The final position may be maintained with a second wire and/or a staple. The tourniquet is then deflated and careful inspection of the vascular status is carried out. Closure is routine and a posterior splint is applied over a sterile dressing. Hand surgical procedures included: bilateral thumb metacarpophalangeal joint capsulorrhaphies, syndactyly release, opponens transfer, and resection of a Streeter's band and distal skin remnant. Complications. There were eight significant complications recorded in the 22 derotational osteotomies, producing an overall complication rate of 36%. There was one wound infection, which responded to drainage and appropriate antibiotic administration. The osteotomy in three forearms slipped from the original position of correction. The magnitude of loss was 60°,50°, and 20°, respectively. Two of these patients, one corrected at the synostosis and one by distal radius and ulnar osteotomies, had no internal fixation and the third lost the fixation provided by a Blount staple due to wound sepsis. There were four instances of postoperative circulatory compromise, three in patients with synostosis osteotomies, and one in a distal radius and ulna osteotomy. In one patient a palmar fasciotomy was performed on the seventh postoperative day. In another the cast was removed three successive times and remanipulation was necessary on the thirteenth day after surgery. In the third patient mild tightness of her digital flexors was noted several weeks after surgery when passive extension was attempted. No specific therapy was instituted. In all three of the four instances the initial correction was in excess of 85° of rotation. In none of these patients did permanent disability result. In a fourth patient an impending Volkman's ischemia was noted on the second postoperative day and it failed to clear with continued elevation and dressing removal. The patient was taken back to the operating room and compartment pressure readings both on the
Congenital radioulnar synostosis
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Table I. Results Poor
Unilateral involvement Bilateral involvement Total
7
6
0
10
6
2
17
12
2
0
2
Of the 17 patients undergoing derotation osteotomies 82% had good or excellent results.
flexor and extensor side confirmed the clinical impression and the forearm was rotated back to its preoperative position. The pressures then fell to normal. Thus, no fasciotomies were necessary. The patient underwent subsequent "rederotation" without further circulatory compromise. After that procedure the patient was noted to have a posterior interosseous nerve syndrome that cleared spontaneously in 6 weeks time. Unlike the other three patients with neurovascular complications, his forearm was derotated only 40°. However, like the others, he had an excellent result.
Surgical results The usual problem in establishing objective criteria for measuring results was present. This was complicated by the fact that even the best results did not yield a normal forearm as the synostosis persisted. The following rating systems seemed appropriate: Excellent. Correction of the anatomic deformity radiographically and clinical examination with minimal functional restriction remaining. Good. Correction of the anatomic deformity radiographically and clinical examination with troublesome residual functional restriction. Fair. Loss of correction and troublesome residual functional restriction, but further surgery not performed. Poor. Loss of correction requiring additional surgery, major neurovascular complication with residual deficit. Seventeen patients underwent derotational osteotomies and 15 of the 17 were interviewed and examined. Information on the others was obtained by chart review. The average time of follow-up was 12V2 years, with a range from 1 to 26 years. Five were seen more than 15 years after surgery. Using the criteria listed above, the results are noted in Table I. Eighty-two percent had good or excellent results. Both patients graded with good results had bilateral involvement and had derotation of their nondominant forearm. This left them with considerable functional impairment. Fair results were produced by failure to
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Fig. 6. Fixation in supination is undesirable cosmetically and functionally. This position requires shoulder hyperabduction to do daily activities such as eating.
maintain the position of correction following osteotomy. In one case, no internal fixation was used. Thirty degrees of positional correction was lost and the osteotomy angulated into 25° of valgus. In the other instance, a wound infection was followed by displacement of the fixation staple. This synostosis osteotomy healed in 30° of varus and 20° of rotational correction was lost. Neither patient required additional surgery. The poor result occurred when loss of position after shaft osteotomies left the foreann essentiallly uncorrected. No internal fixation was used and the cast failed to maintain correction. Eight years later, at age 14, the patient had a second osteotomy and it was successful. Distal radial osteotomy was successful in two patients. In both instances union was achieved without difficulty after derotation of 85° and 90°, respectively. Follow-up of 7 and 20 years, respectively, revealed satisfactory alignment of the foreann and wrist without recurrent angulation. Should the forearm be left in some degree of pronation or put into supination? In the report by Green and Mital,16. 17 it was suggested that one forearm be put in supination of 20° to 300 in patients with bilateral radioulnar synostosis, as Dr. Green felt that this would allow a more complete spectrum of function. Ten of the
15 patients in that report had bilateral involvement and
five of these had one forearm placed in supination. In our series, two of the patients having a forearm placed in supination had only unilateral involvement and one had bilateral involvement. These patients report that fixation in this position is awkward socially and not pleasing cosmetically. More important, however, is the fact that it is undesirable functionally (Fig. 6). Fixed supination of the forearm requires extreme positions of shoulder abduction and internal rotation to bring the foreann into pronation. Activities such as typing, writing, or piano playing demand prolonged maintenance of this position, which is awkward and extremely fatiguing. The advantage of "receiving coins gracefully"17 was not felt to be a worthwhile trade-off. Our series suggests that in unilateral cases the forearm should not be put in supination, but is best placed in about 15° of pronation. In bilateral cases knowing the planned career of the patient would help in making the decision; this is clearly impossible in the very young and is uncertain in the older child. If one chooses to perform surgery before these decisions can be made, then the dominant extremity should be put in 10° to 20° of pronation and the other in neutral. Wrist hypermobility allows some supination and pronation.
Vol. 8 , No.6 November 1983
Supination of 20° to 30°16. most cases .
Congenital radioulnar sYllostosis
17
is probably undesirable in
Conclusions
E.
1. Congenital radioulnar synostosis is a rare anom-
aly that occurs with greater frequency in patients with sex chromosome abnormalities. The final outcome appears to be failure of proximal radioulnar joint morphogenesis in the embryo . 2. Associated congenital anomalies occur in one third of patients and can involve most other major organ systems. 3. Males are affected only slightly more often than females. This is at variance with the usual 2 : I male to female ratio previously reported . 4. Sixty percent of patients have bilateral involvement. Bilateral synostosis and/or a high degree of fixed pronation produce severe functional deficiencies. 5 . There is a continuum of anatomic variation in these patients involving varying lengths of synostosis and the presence or absence of a radial head. This spectrum conforms logically to current embryologic concepts. This disputes the classical concept of the existence of two distinct types of radioulnar synostosis . 6. Rotational hypermobility of the wrist is uniformly present and is of great functional value. It appears to persist into adulthood. 7. Twenty of 33 patients in our study underwent surgery. Three types of operations were performed: derotational osteotomy, osteotomy to correct wrist angulation, and hand surgical procedures. From analysis of the derotational osteotomies, we conclude that: A. Derotation is desirable on any forearm fixed in more than 60° of pronation . B. The dominant hand should be given preference in bilateral cases. C. It is best to carry out the operation before the child begins school. D. Osteotomy through the synostosis is technically easier than other methods and gives reliable results. Internal fixation by an intramedullary wire should be used and is best removed in growing children. Osteotomies through the distal radius and ulna are more difficult and carry similar potential complications . Only two osteotomies through the radius alone were performed-both without complications. This may be an alternative site for osteotomy and may carry less threat of
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complication; our series is too small to be certain. Special attention must be given to the vascular status of the extremity in the operating room and in the early postoperative period . Internalized transfixing devices (crossed Kirschner wires, staples) are to be used with caution if a great deal of derotation is accomplished. They prevent rotation to the preoperative position if neurovascular problems arise. If neurovascular compromise occurs, the extremity should be dederotated and compartment pressures should be rechecked before doing fasciotomies. Derotation can be accomplished subsequently on the ward under parenteral analgesia. This allows for gradual rederotation and observation of the circulatory status. Any derotation requiring a change of greater than 85° should be accomplished in two stages . The ideal final position for the forearm in unilateral cases is from neutral to 20° of pronation. In our series, fixed supination in the unilateral cases was functionally and cosmetically undesirable. The ideal final position for the forearm in bilateral cases is less clear. A sense of the patient's career plans may help. Without that information, it would appear to be best if the dominant extremity was put in 10° to 20° of pronation and the other in neutral. Good to excellent results were achieved in 82% of patients undergoing this operation. The surgical pessimism expressed in the literature is misleading. Careful patient selection and surgical technique yield a high degree of success. Therefore, to withhold surgery from a severely affected individual seems unreasonable.
REFERENCES I. Morrison J: Congenital radio-ulnar synostosis. Br Med J 2:1337,1892 2. Bootdyrin DE: Bilateral congenital radio-ulnar synostosis. Am J Surg 32:221-3, 1918 3. Cohn BNE: Congenital bilateral radio-ulnar synostosis . J Bone Joint Surg 14:404-5, 1932 4. Cross AR: Congenital bilateral radioulnar synostosis . Am J Dis Child 58: 1259-60, 1939
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5. Lunn JR: Congenital synostosis of radio-ulnar articulations. Br Med J 1 :4 99 , 1906 6. Kopelowitz JC: A case of congenital radio-ulnar synostosis. JAMA 72:21, 1919 7. Painter CF: Congenital pronation of the foreanns. Am J Orthop Surg 7:529-32, 1910 8. Blodgett WE: Congenital luxation of the head of the radius. Report of two cases. Analysis of fifty-one cases. Summary . Certain other considerations. Conclusions. Am J Orthop Surg 3: 25 3-70, 1905- 1906 9. Adams JE: Congenital coalescence of radius and ulna child. Proc Royal Soc Med London 6: 136-7, 1912-1913 10. Blaine ES: Congenital radio-ulnar synostosis, with report of a case. Am J Surg 7:429-34, 1930 II . Davenport CB, Taylor HL, Nelson LA: Radio-ulnar synostosis. Arch Surg 8:705-62, 1924 12. Dawson HGW: A congenital deformity of the forearm and its operative treatment. Br Med J 2: 833-5, 1912 13. Thomas GF: Congenital radio-ulnar synostosis. Am J Roentgenol 4:571-3, 1917 14. Clarke JJ: Congenital fusion of the upper end of the radius to the ulna. Proc R Soc Med London 7:120-212, 1913-1914 15 . Fahlstrom S: Radio-ulnar synostosis. J Bone Joint Surg 14:395-403, 1932 16. Green WT, Mital M: Congenital radio-ulnar synostosis: Its surgical treatment. J Bone Joint Surg [Am] 51:1042, 1969 17. Green WT, Mital M: Congenital radio-ulnar synostosis: Surgical treatment. J Bone Joint Surg [Am] 61 :738, 1979 18. Fielding JW: Radio-ulnar crossed union following displacement of the proximal radial epiphysis. J Bone Joint Surg [Am] 46:1277-8,1964 19. Sledge CB: Some morphologic and experimental aspects of limb development. Clin Orthop 44:241-64, 1966 20. Lewis WH: The development of the arm in man. Am J Anat 1: 169-83, 1901 21. Wilkie DPD: Congenital radio-ulnar synostosis. Br J Surg 1:366-75, 1914
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22. Hansen HO, Andersen ON: Congenital radio-ulnar synostosis. Acta Orthop Scand 41:225-30 , 1970 23. Wynn-Davies R: Heritable disorders in orthopedic practice. Oxford, 1973, Blackwell Scientific Publications , p 175 24. Cleveland WW, Arias D, Smith GF: Radio-ulnar synostosis, behavioral disturbance and XXY chromosomes. J Pediatr 74: 103-6, 1969 25. Zeleski WA, Houson CS, Pozsonyi J, Ying KL: The XXXY Chromosome anomaly: Report of three new cases and review of 30 cases from the literature . Can Med Assoc J 94: 1143-54, 1966 26. Kelekian H, Doumanian A: Swivel for proximal radioulnar synostosis. J Bone Joint Surg [Am] 39:945-52, 1957 27. Fergeson-Smith EA, Johnston A W, Handmaker SO: Primary amentia and micro-orchidism associated with an XXYY sex chromosome constitution. Lancet 2: 184-7, 1960 28. Robinson GC, Miller JR, Dill FJ, Kamburoff TD: Kline-Felter 's syndrome with the SSYY sex chromosome complex. J Pediatr 65 :226-32, 1964 29. Feidt WW: Congenital radio-ulnar synostosis. Surg Gynecol Obstet 24:696-700, 1917 30. Stretton JL: Congenital synostosis of radio-ulnar articulations . Br Med J 2:1519, 1905 31. Roth PB: Case of congenital radio-ulnar synostosis after operation in a boy , aged 10. Proc R Soc Med London [Surg] 15:4, 1921-1922 32. Tachdjian MO: Pediatric orthopedics. Philadelphia , 1972, WB Saunders Co , p 105 33. Sever JW: Congenital radio-ulnar synostosis. Surg Gynecol Obstet 24: 203-4, 1919 34. Gibson A: A critical consideration of congenital radioulnar synostosis with special reference to treatment. J Bone Joint Surg 5:303 , 1923
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HAND SURGERY
NOVEMBER 1983 VOLUME 8,
NUMBER 6
Official journal AMERICAN SOCIETY FUR SURGERY OF THE HAND
ORIGINAL COMMUNICATIONS Congenital radioulnar synostosis Congenital radioulnar synostosis can be severely disabling, especially if it is bilateral or if severe hyperpronation exists. Functionally, patients with severe deformity have trouble getting a cup to the mouth, using eating utensils, or accepting objects in an open palm. Of 33 patients (17 bilateral and 7 unilateral) underwent derotational osteotomy, with the majority being performed through the synostosis held with, an intramedullary wire and secondary transfixing device. There were eight complications, four involving neurovascular compromise. In bilateral cases, the best end position appears to be 10% to 15% of pronation in the dominant extremity and neutral in the other. Eighty-two percent of the patients had good or excellent results. (J HAND SURG 9:829-38, 1983.)
Barry P. Simmons, M.D., William W. Southmayd, M.D., and Edward 1. Riseborough, M.D., Boston, Mass.
Congenital synostosis of the proximal radius and ulna is a rare malformation of the upper limb. The first anatomic description of this entity was given by Sandi fort in 1793. One hundred years later, Morrison described a clinical case and demonstrated the classical physical findings. 1 The use of x-rays since 1900 led to more individual case reports of this lesion. 2-14 Fahlstrom 'S15 exhaustive review in 1932 listed 195 patients. More recently, Green and MitaP6, 17 have reported fifteen cases. In all, there have been fewer than 250 cases reported to date. This study is based on an analysis of 33 patients with radioulnar synostosis treated at Children's Hospital Medical Center between the years 1949 and 1980. Any cases of proximal radioulnar crossed union following fracture were excluded from the series. IS From the Departments of Orthopedic Surgery, Harvard Medical School, Children's Hospital Medical Center, Brigham and Women's Hospital, Boston, Mass. Received for publication Feb. 18, 1982; accepted in revised form Nov. 9, 1982. Reprint requests to: Barry P. Simmons, M.D., Chief, Hand Surgery Service, Department of Orthopedic Surgery, Children's Hospital Medical Center, 300 Longwood Ave., Boston, MA 02115.
This paper compares the findings in our large series with those in the literature, examines the surgical alternatives and presents a long-term follow-up on selected operative cases.
Embryology During the embryonic period of fetal development the upper limb bud arises from the unsegmented body wall at 26 days of age. Growth and differentiation continue until 48 days, when all external characteristics of the adult limb are present. 19 The elbow is first discernible at 35 days. At this stage there are three connected cartilaginous anlage present destined to become the humerus, the radius, and the ulna. Soon thereafter longitudinal segmentation produces a separation of the distal radius and ulna, but for a time their proximal ends are united and share a common perichondrium. 20 Therefore, abnormal genetic or tetatogenic factors operating at this time would interrupt subsequent proximal radioulnar joint morphogenesis. Such interference with joint formation would allow for later ossification of the entire proximal cartilaginous model and produce complete bony synostosis. If joint development continued somewhat further before deve!THE JOURNAL OF HAND SURGERY
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Fig. 1. In bilateral cases with hyperpronation "backhanded" positioning is necessary to get objects to one's mouth.
opmental arrest occurred, this could logically lead to a smaller area of coalition and the presence of a rudimentary radial head. During this period of intrauterine development, the forearm is in a position midway between neutral and full pronation. Wilke surmised that "the position of pronation found in this deformity is therefore normal for the young embryo . "21 Hence, it would seem that failure of proximal radioulnar joint differentiation leaves the forearm forever in its fetal position. With the exception of one case,17 in all previous clinical cases the forearm has been fixed in this position.1 5. 21 Etiology. Although the etiology is unknown, there appears to be a genetic basis for this condition. Positive family histories have been reported ll • 12. 15,22 and it is seen in disorders such as acropolysyndactyly (Carpenter's syndrome), acrocephalosyndactyly (Apert's syndrome), arthrogryposis, and mandibulofacial dysostosisP More specific evidence for a genetic etiology is provided by noting its presence in nondysfunctional sex chromosomal abnormalities, especially Klinefelter's syndrome and its variants. 21, 26-28 Clinical factors Review of previous cases3, 13. 16, 17 produces a history and physical examination results consistent with our series as noted below. Radiologically findings in our patients' were simihr to those reported8 , 29 and are consistent with a spectn,m of length of the fusion mass as opposed to an attempt to differentiate "types" by Wilkie .21 Early surgical treatment was aimed at restoring mo-
tion to the affected forearm. This has included simple division of the bony bridge tl or resection of the synostotic proximal radius, saving the bicepital tuberosity with l • 4. :!1 and without 30 muscle interposition and with division of the interosseous membrane. 12 None of these procedures restored motion. Kelekian and Doumanian 2fi devised a metallic swivel to be put in the intramedullary canal of the radius between the supinator and pronator teres. This was used in conjunction with resection of the distal ulna and transfer of the flexor carpi ulnaris to the dorsum of the hand to help restore supination . They reported good results in posttraumatic , proximal radioulnar synostosis. Tachdjian, 32 however, reports its use in congenital radioulnar synostosis with disappointing results presumably due to contracture of the nonosseous forearm structures. As a result of these experiences, several authors concluded that there was no surgical treatment for this problem .4 . 6. 22. 2H A more practical solution to the problem was first offered by Sever at Children's Hospital in Boston in 1919. 33 He thought that the functionally deficient, pronated forearm should be fixed in a new, more useful position. He pointed out that one could pronate a forearm fixed neutrally or in supination by abduction and internal rotation of the shoulder. However, the chest wall and trunk block any attempt to use the shoulder to supinate a forearm fixed in pronation . His operative technique involved resection of a Y2-inch segment of the proximal radial shaft just distal to the synostosis. He then rotated the forearm around the ulna into supination and held this position in a cast . This apparently gave excellent functional results in a single patient. The usefulness of this concept was reinforced 4 years later by Gibson 34 who stated that' 'full supination is certainly not the optimum position; full pronation is not so good as the midposition. An osteotomy to bring about this change of position from full to semipronation is probably justified in some people." A subsequent report by Green and MitaP6. 17 included 15 patients with this disorder and they found that the grossly pronated forearm constituted a "severe functional and cosmetic handicap." They also recommended surgical de rotation of the forearm. Their goal in bilateral cases was to place one hand in 20° to 30° of supination and the other in 30° to 45° of pronation . The operative technique advocated was transverse osteotomy through the synostosis with the use of Kirschner wires for maintenance of position. Clinical series There were 33 patients with congenital radioulnar synostosis seen at Children's Hospital Medical Center during this 3 I-year time period. Charts and x-ray films
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Fig. 2. Patients find (A) feeding themselves and (B) "accepting" objects such as coins awkward and difficult.
were reviewed on each child and physical examination was perfonned on the 24 patients available for followup. Of the 33 patients, 19 were boys and 14 were girls. Nineteen had bilateral involvement, with a sex ratio of II boys to 8 girls. Unilateral involvement occurred in 14 cases, with a sex ratio of 8 boys to 6 girls. Of these unilateral cases, 9 were the right ann and 5 were the left. There was a total of 52 affected foreanns in the 33 patients . The average age at which the affliction was noted by the parents was 21h years. The earliest recognition was at the first postnatal examination-the latest was in a unilateral case at the age of 10. Twelve cases were discovered before the age of I year. Functional complaints were specifically mentioned in the charts of 22 patients . They included: (1) difficulty in holding or using small objects such as spoons or pencils, (2) inability to dress themselves due to poor manipulative ability in dealing with belt buckles and buttons, (3) backhanded position in holding objects such as bottles or toys (Fig. I), (4) difficulty in feeding themselves (Fig. 2, A), (5) inability to accept small objects in their hands , (e.g., coins) (Fig. 2, B), and (6) difficulty competing in sports requiring upper extremity dexterity. These functional deficiencies were definitely more common in patients with bilateral involvement and in those with the more severe degrees of fixed
pronation. Cosmetic appearance was mentioned as a cause of concern, but usually only by the parents . Additional congenital anomalies were present in II of the 33 patients. The organ systems involved were the musculoskeletal, cardiovascular, thoracic, central nervous system, renal, and gastrointestinal. Specifically these included: Thumb . Aplasia (three cases), polydactyly, Streeter's dysplasia, hypoplasia Digits. Syndactyly (four cases) Carpus. Partial carpal coalition Cardiac . Tetralogy of Fallot, ventricular septal defect Thoracic. Hypoplasia of first and second ribs, hypoplasia of pectoral musculature Central nervous system . Microcephaly, hydrocephalus (two cases), encephalocele, mental retardation, slow developmental milestones, and right spastic hemiplegia Renal . Unilateral hypoplasia Gastrointestinal . Umbilical hernia A positive family history was present in only one instance. This was a male patient with bilateral involvement. His paternal grandmother and uncle both had similar afflictions. Two patients in the series with bilateral involvement each have children of their own, but none have synostosis. One child had chromosomal
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Fig. 3. Passive rotational hypermobility of the wrist was a universal finding . This is obviously an adaptive phenomenon to compensate for the absence of forearm rotation . analysis perfonned that revealed a nonnal female karyotype. Possible teratogenic factors included one case of first trimester rubella, which produced a severely defonned child who died within 1 year, and another case in which the mother used rectal suppositories containing cortisone in the first 6 weeks of pregnancy .
Physical examination Data on the carrying angle of the affected elbow was available in 22 patients. Assuming the nonnal carrying angle to be 15° to 20° of valgus, it was increased in 2 patients, nonnal in 5, and less than nonnal in 15. In those instances in which the extended elbow was in neutral or varus, there was no correlation with the presence or absence of a radial head .
Elbow extension was less than full in 22 of 30 patients on whom this infonnation was available. The average fixed flexion contracture was 16°, with a range from 5° to 30°. Six patients had full extension and two had hyperextension. Marked shortening of the fore ann occurred in four instances. Two had unilateral involvement with a length differential of 8 cm. The other two patients had bilateral involvement, but the shortening was readily apparent. In two of these patients the synostosis extended more than halfway down the foreann. In three other unilateral patients shortening was observed, but it did not exceed 2 cm. Rotational hypennobility of the wrist was unifonnly present in the affected extremities (Fig. 3). It was most prominent in children, but persisted into adulthood .
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Fig. 4. Radiologically , a broad spectrum of synostosis is seen. A, Virtually total synostosis; B, shorter area of synostosis with radial head absent (most common); C, short synostosis with radial head present but subluxed; and D, deformed distal radioulnar and radiocarpal joints.
There was no increased mobility or instability in other planes of wrist motion . Atotal arc of rotation from 30° to 45° was the rule . Presumably this is due to ligamentous laxity secondary to continued rotational stress on the wrist in the absence of forearm rotation. None of the patients complained of wrist pain or stiffness. Positional data. Analysis of the fixed position of the forearms in these patients revealed 38% in less than 30° of pronation, 20% between 30° and 60°, and 42% fixed in more than 60° of pronation . Radiographic analysis Analysis of the x-ray films of these patients did not confirm the classical description of two distinct types of radioulnar synostosis as proposed by Wilkie. 2 Rather, there appears to be a spectrum of anatomic variation. This ranges from total synostosis (Fig. 4, A) with marked shortening of the entire forearm to progressively shorter areas of synostosis without the presence of a radial head (Fig . 4, B). Short synostosis often accompanies radial head presence (Fig . 4, C) , which finally gives way to synostotic absence and minor radial head deformity in a patient with a 45° arc of rotation on one side and synostosis with a radial head on the other. The longer synostotic areas showed continuity of can-
cellous bone throughout the coalition, while shorter synostoses had varying amounts of cortical bone centrally. The distal aspect of the synostosis was arcuate in shape. The presence of such a continuum of involvement- ranging from quite severe to almost normalconforms logically with the embryologic postulate of developmental arrest at varying stages of fetal maturation . Correlated with the physical examination results, the more extensive synostoses with radial head absence had a greater degree of fixed pronation . When present, the radial head is not always dislocated with respect to the capitellum . The proximal radial epiphysis appeared at the expected time and developed along a normal sequence. At the completion of growth, the radial heads had a normal concave configuration. When there was absence of the radial head, the capitellum seemed to have an abnormally globular appearance. Radial shaft bowing was common but varied in its severity. There was a uniform absence of proximal radial tapering at the level where the bicipital tuberosity is usually located. The distal radioulnar joint was clinically normal in most patients. In some there was mild hypoplasia of the distal ulna with subluxation radiologically. In two cases
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Fig. 5. Osteotomy through the synostosis held with an intramedullary pin was the most common, simplest procedure . A second "stabilizing" device may be used (crossed wire), but should be left accessible in case neurovascular compromise requires dederotation. In this patient a percutaneous pin was used through the distal fragment and secured in plaster.
the distal radius was grossly deranged with marked palmar and ulnar deviation of the articulating surface (Fig . 4,D) .
Indications for surgery The functional deficit associated with radioulnar synostosis is dependent on two main factors: (I) the obvious loss of forearm axial rotation, and (2) the position in which the forearm is fixed . With 60° or more of fixed pronation, the child has the serious function restrictions noted previously . Clearly, these patients benefit from having their forearms placed in a more functionally and cosmetically acceptable position. Logically , the dominant arm should be derotated first and we believe that it should be done before they start school to maximize their gain from surgery. Children whose forearms are fused in positions from neutral to 15° of pronation function very well; their only restrictions involve accepting objects in an open palm and performing very specific athletic activities such as pull-ups. Some have difficulty eating , but most are not markedly incapacitated by this degree of pronation. These children learn to function so well that surgery is unnecessary. For those patients that fall in between these clear extremes, one must carefully individualize the need for surgical intervention. Important factors in the decision are whether there is unilaterality or bilaterality of involvement and the results of careful history and physical examination that allow analysis of the child's functional capacity. If this capacity is severely limited , surgical correction should be advised .
Analysis of operative series There were 29 operations performed on 20 patients, eight of whom had unilateral involvement and 12 had
bilateral deformity . Of the surgical procedures performed , 22 involved derotation of the forearm; two were to correct ulnar deviation of the wrist and five were hand operations. Only one patient underwent derotation of both forearms. No effort to create motion was attempted in this series. Various techniques were used to achieve derotation of the forearm. In four patients, only the radius was osteotomized, with rotation of the distal radial segment around the ulna through the distal radioulnar joint. The shafts of the radius and ulna were osteotomized in two patients. In 16 forearms the osteotomy was created through the synostosis, with subsequent derotation of the distal forearm-hand unit. Seven of 14 patients with unilateral involvement underwent derotation as did 10 of 19 with bilateral affliction. The average age at the first osteotomy was 8 years, with a range from 21/2 to 171/2 years. The average initial position in the surgical patients was 82° of pronation, with a range from 45° to 120° of pronation. Only one forearm fixed in less than 60° of pronation had surgery . The average de rotation achieved with a single osteotomy was 67°, the least being 25° and the most 90°. Two children required two-stage de rotation and one had three operations on a single forearm moving from 120° of pronation to neutral. One patient had surgery on both forearms. The final position averaged 8° of pronation. Three patients were moved to a position of fixed supination: two of 15° and one of 20°. Of these, one patient had bilateral synostoses and two were unilateral. In this series internal fixation was achieved either by Kirschner wires, Steinmann pins, or Blount staples. In three cases no internal fixation was used. All patients subsequently spent from 6 to 24 weeks in a long arm cast. In every case but one the fixation devices were removed later.
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Operative procedure The most commonly performed procedure was, as suggested by Dr. William T. Green,16 an osteotomy through the synostosis (Fig. 5). The skin incision is placed along the subcutaneous border of the ulna. Deep fascia is opened longitudinally along the anconeus and the extensor carpi ulnaris. The synostosis is exposed by subperiosteal elevation dorsally and palmarly. The midportion of the synostosis is identified and osteotomized. A Steinmann pin is then placed down the intermedullary canal of the ulna across the osteotomy site to maintain axial alignment and the derotation is performed about this pivot point. Soft tissue resistance limits the degree to which the forearm may be derotated. The final position may be maintained with a second wire and/or a staple. The tourniquet is then deflated and careful inspection of the vascular status is carried out. Closure is routine and a posterior splint is applied over a sterile dressing. Hand surgical procedures included: bilateral thumb metacarpophalangeal joint capsulorrhaphies, syndactyly release, opponens transfer, and resection of a Streeter's band and distal skin remnant. Complications. There were eight significant complications recorded in the 22 derotational osteotomies, producing an overall complication rate of 36%. There was one wound infection, which responded to drainage and appropriate antibiotic administration. The osteotomy in three forearms slipped from the original position of correction. The magnitude of loss was 60°,50°, and 20°, respectively. Two of these patients, one corrected at the synostosis and one by distal radius and ulnar osteotomies, had no internal fixation and the third lost the fixation provided by a Blount staple due to wound sepsis. There were four instances of postoperative circulatory compromise, three in patients with synostosis osteotomies, and one in a distal radius and ulna osteotomy. In one patient a palmar fasciotomy was performed on the seventh postoperative day. In another the cast was removed three successive times and remanipulation was necessary on the thirteenth day after surgery. In the third patient mild tightness of her digital flexors was noted several weeks after surgery when passive extension was attempted. No specific therapy was instituted. In all three of the four instances the initial correction was in excess of 85° of rotation. In none of these patients did permanent disability result. In a fourth patient an impending Volkman's ischemia was noted on the second postoperative day and it failed to clear with continued elevation and dressing removal. The patient was taken back to the operating room and compartment pressure readings both on the
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Table I. Results Poor
Unilateral involvement Bilateral involvement Total
7
6
0
10
6
2
17
12
2
0
2
Of the 17 patients undergoing derotation osteotomies 82% had good or excellent results.
flexor and extensor side confirmed the clinical impression and the forearm was rotated back to its preoperative position. The pressures then fell to normal. Thus, no fasciotomies were necessary. The patient underwent subsequent "rederotation" without further circulatory compromise. After that procedure the patient was noted to have a posterior interosseous nerve syndrome that cleared spontaneously in 6 weeks time. Unlike the other three patients with neurovascular complications, his forearm was derotated only 40°. However, like the others, he had an excellent result.
Surgical results The usual problem in establishing objective criteria for measuring results was present. This was complicated by the fact that even the best results did not yield a normal forearm as the synostosis persisted. The following rating systems seemed appropriate: Excellent. Correction of the anatomic deformity radiographically and clinical examination with minimal functional restriction remaining. Good. Correction of the anatomic deformity radiographically and clinical examination with troublesome residual functional restriction. Fair. Loss of correction and troublesome residual functional restriction, but further surgery not performed. Poor. Loss of correction requiring additional surgery, major neurovascular complication with residual deficit. Seventeen patients underwent derotational osteotomies and 15 of the 17 were interviewed and examined. Information on the others was obtained by chart review. The average time of follow-up was 12V2 years, with a range from 1 to 26 years. Five were seen more than 15 years after surgery. Using the criteria listed above, the results are noted in Table I. Eighty-two percent had good or excellent results. Both patients graded with good results had bilateral involvement and had derotation of their nondominant forearm. This left them with considerable functional impairment. Fair results were produced by failure to
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Fig. 6. Fixation in supination is undesirable cosmetically and functionally. This position requires shoulder hyperabduction to do daily activities such as eating.
maintain the position of correction following osteotomy. In one case, no internal fixation was used. Thirty degrees of positional correction was lost and the osteotomy angulated into 25° of valgus. In the other instance, a wound infection was followed by displacement of the fixation staple. This synostosis osteotomy healed in 30° of varus and 20° of rotational correction was lost. Neither patient required additional surgery. The poor result occurred when loss of position after shaft osteotomies left the foreann essentiallly uncorrected. No internal fixation was used and the cast failed to maintain correction. Eight years later, at age 14, the patient had a second osteotomy and it was successful. Distal radial osteotomy was successful in two patients. In both instances union was achieved without difficulty after derotation of 85° and 90°, respectively. Follow-up of 7 and 20 years, respectively, revealed satisfactory alignment of the foreann and wrist without recurrent angulation. Should the forearm be left in some degree of pronation or put into supination? In the report by Green and Mital,16. 17 it was suggested that one forearm be put in supination of 20° to 300 in patients with bilateral radioulnar synostosis, as Dr. Green felt that this would allow a more complete spectrum of function. Ten of the
15 patients in that report had bilateral involvement and
five of these had one forearm placed in supination. In our series, two of the patients having a forearm placed in supination had only unilateral involvement and one had bilateral involvement. These patients report that fixation in this position is awkward socially and not pleasing cosmetically. More important, however, is the fact that it is undesirable functionally (Fig. 6). Fixed supination of the forearm requires extreme positions of shoulder abduction and internal rotation to bring the foreann into pronation. Activities such as typing, writing, or piano playing demand prolonged maintenance of this position, which is awkward and extremely fatiguing. The advantage of "receiving coins gracefully"17 was not felt to be a worthwhile trade-off. Our series suggests that in unilateral cases the forearm should not be put in supination, but is best placed in about 15° of pronation. In bilateral cases knowing the planned career of the patient would help in making the decision; this is clearly impossible in the very young and is uncertain in the older child. If one chooses to perform surgery before these decisions can be made, then the dominant extremity should be put in 10° to 20° of pronation and the other in neutral. Wrist hypermobility allows some supination and pronation.
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Supination of 20° to 30°16. most cases .
Congenital radioulnar sYllostosis
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is probably undesirable in
Conclusions
E.
1. Congenital radioulnar synostosis is a rare anom-
aly that occurs with greater frequency in patients with sex chromosome abnormalities. The final outcome appears to be failure of proximal radioulnar joint morphogenesis in the embryo . 2. Associated congenital anomalies occur in one third of patients and can involve most other major organ systems. 3. Males are affected only slightly more often than females. This is at variance with the usual 2 : I male to female ratio previously reported . 4. Sixty percent of patients have bilateral involvement. Bilateral synostosis and/or a high degree of fixed pronation produce severe functional deficiencies. 5 . There is a continuum of anatomic variation in these patients involving varying lengths of synostosis and the presence or absence of a radial head. This spectrum conforms logically to current embryologic concepts. This disputes the classical concept of the existence of two distinct types of radioulnar synostosis . 6. Rotational hypermobility of the wrist is uniformly present and is of great functional value. It appears to persist into adulthood. 7. Twenty of 33 patients in our study underwent surgery. Three types of operations were performed: derotational osteotomy, osteotomy to correct wrist angulation, and hand surgical procedures. From analysis of the derotational osteotomies, we conclude that: A. Derotation is desirable on any forearm fixed in more than 60° of pronation . B. The dominant hand should be given preference in bilateral cases. C. It is best to carry out the operation before the child begins school. D. Osteotomy through the synostosis is technically easier than other methods and gives reliable results. Internal fixation by an intramedullary wire should be used and is best removed in growing children. Osteotomies through the distal radius and ulna are more difficult and carry similar potential complications . Only two osteotomies through the radius alone were performed-both without complications. This may be an alternative site for osteotomy and may carry less threat of
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complication; our series is too small to be certain. Special attention must be given to the vascular status of the extremity in the operating room and in the early postoperative period . Internalized transfixing devices (crossed Kirschner wires, staples) are to be used with caution if a great deal of derotation is accomplished. They prevent rotation to the preoperative position if neurovascular problems arise. If neurovascular compromise occurs, the extremity should be dederotated and compartment pressures should be rechecked before doing fasciotomies. Derotation can be accomplished subsequently on the ward under parenteral analgesia. This allows for gradual rederotation and observation of the circulatory status. Any derotation requiring a change of greater than 85° should be accomplished in two stages . The ideal final position for the forearm in unilateral cases is from neutral to 20° of pronation. In our series, fixed supination in the unilateral cases was functionally and cosmetically undesirable. The ideal final position for the forearm in bilateral cases is less clear. A sense of the patient's career plans may help. Without that information, it would appear to be best if the dominant extremity was put in 10° to 20° of pronation and the other in neutral. Good to excellent results were achieved in 82% of patients undergoing this operation. The surgical pessimism expressed in the literature is misleading. Careful patient selection and surgical technique yield a high degree of success. Therefore, to withhold surgery from a severely affected individual seems unreasonable.
REFERENCES I. Morrison J: Congenital radio-ulnar synostosis. Br Med J 2:1337,1892 2. Bootdyrin DE: Bilateral congenital radio-ulnar synostosis. Am J Surg 32:221-3, 1918 3. Cohn BNE: Congenital bilateral radio-ulnar synostosis . J Bone Joint Surg 14:404-5, 1932 4. Cross AR: Congenital bilateral radioulnar synostosis . Am J Dis Child 58: 1259-60, 1939
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5. Lunn JR: Congenital synostosis of radio-ulnar articulations. Br Med J 1 :4 99 , 1906 6. Kopelowitz JC: A case of congenital radio-ulnar synostosis. JAMA 72:21, 1919 7. Painter CF: Congenital pronation of the foreanns. Am J Orthop Surg 7:529-32, 1910 8. Blodgett WE: Congenital luxation of the head of the radius. Report of two cases. Analysis of fifty-one cases. Summary . Certain other considerations. Conclusions. Am J Orthop Surg 3: 25 3-70, 1905- 1906 9. Adams JE: Congenital coalescence of radius and ulna child. Proc Royal Soc Med London 6: 136-7, 1912-1913 10. Blaine ES: Congenital radio-ulnar synostosis, with report of a case. Am J Surg 7:429-34, 1930 II . Davenport CB, Taylor HL, Nelson LA: Radio-ulnar synostosis. Arch Surg 8:705-62, 1924 12. Dawson HGW: A congenital deformity of the forearm and its operative treatment. Br Med J 2: 833-5, 1912 13. Thomas GF: Congenital radio-ulnar synostosis. Am J Roentgenol 4:571-3, 1917 14. Clarke JJ: Congenital fusion of the upper end of the radius to the ulna. Proc R Soc Med London 7:120-212, 1913-1914 15 . Fahlstrom S: Radio-ulnar synostosis. J Bone Joint Surg 14:395-403, 1932 16. Green WT, Mital M: Congenital radio-ulnar synostosis: Its surgical treatment. J Bone Joint Surg [Am] 51:1042, 1969 17. Green WT, Mital M: Congenital radio-ulnar synostosis: Surgical treatment. J Bone Joint Surg [Am] 61 :738, 1979 18. Fielding JW: Radio-ulnar crossed union following displacement of the proximal radial epiphysis. J Bone Joint Surg [Am] 46:1277-8,1964 19. Sledge CB: Some morphologic and experimental aspects of limb development. Clin Orthop 44:241-64, 1966 20. Lewis WH: The development of the arm in man. Am J Anat 1: 169-83, 1901 21. Wilkie DPD: Congenital radio-ulnar synostosis. Br J Surg 1:366-75, 1914
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22. Hansen HO, Andersen ON: Congenital radio-ulnar synostosis. Acta Orthop Scand 41:225-30 , 1970 23. Wynn-Davies R: Heritable disorders in orthopedic practice. Oxford, 1973, Blackwell Scientific Publications , p 175 24. Cleveland WW, Arias D, Smith GF: Radio-ulnar synostosis, behavioral disturbance and XXY chromosomes. J Pediatr 74: 103-6, 1969 25. Zeleski WA, Houson CS, Pozsonyi J, Ying KL: The XXXY Chromosome anomaly: Report of three new cases and review of 30 cases from the literature . Can Med Assoc J 94: 1143-54, 1966 26. Kelekian H, Doumanian A: Swivel for proximal radioulnar synostosis. J Bone Joint Surg [Am] 39:945-52, 1957 27. Fergeson-Smith EA, Johnston A W, Handmaker SO: Primary amentia and micro-orchidism associated with an XXYY sex chromosome constitution. Lancet 2: 184-7, 1960 28. Robinson GC, Miller JR, Dill FJ, Kamburoff TD: Kline-Felter 's syndrome with the SSYY sex chromosome complex. J Pediatr 65 :226-32, 1964 29. Feidt WW: Congenital radio-ulnar synostosis. Surg Gynecol Obstet 24:696-700, 1917 30. Stretton JL: Congenital synostosis of radio-ulnar articulations . Br Med J 2:1519, 1905 31. Roth PB: Case of congenital radio-ulnar synostosis after operation in a boy , aged 10. Proc R Soc Med London [Surg] 15:4, 1921-1922 32. Tachdjian MO: Pediatric orthopedics. Philadelphia , 1972, WB Saunders Co , p 105 33. Sever JW: Congenital radio-ulnar synostosis. Surg Gynecol Obstet 24: 203-4, 1919 34. Gibson A: A critical consideration of congenital radioulnar synostosis with special reference to treatment. J Bone Joint Surg 5:303 , 1923
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