SURGICAL TREATMENT OF THE THUMB IN THE RUBINSTEIN-TAYBI SYNDROME

V. E. Wuod and J. H. Rubinstein

From the Loma Linda University School of Medicine and the University of Cincinnati College of Medicine.

In a review of 530 individuals with Ruhinstein-Taybi syndrome, 182 (34%) were found to have thumbs in severe radial angulation (“hitch-hiker thumbs”), which prevented opposition and functional gripping strength. Surgery has been performed on 35 thumbs (from 20 patients), usually to correct a delta phalanx deformity. The preferred approach was a closing wedge osteotomy, with a Z-plasty on the concave side to straighten the thumb. In eight and possibly 11 of the 35 thumbs, the angulation deformity or stiffness recurred, emphasizing the importance of proper and careful surgery. We conclude that surgical correction of the deformity is best done before the age of two, so that the thumb is functional during the initial development of hand-eye coordination. Deviation persisting at the age of ten can be corrected by fusing the metacarpo- phalangeal joint.

What would eventually be called the Rubinstein-Taybi syndrome was first described in a single case report by Michail et al. in 1957. The syndrome, however, remained obscure until 1963, when Rubinstein and Taybi reported on seven children with broad thumbs and toes, facial abnormalities, and mental retardation. From that date on, the syndrome has become readily identified as an important disorder of early childhood. One of the authors (JHR) has continued to try to cbllect reports on all the individuals with the syndrome; some 530 cases worldwide have been brought to our attention to date, and these form the basis of the present study.

involves both soft tissues and bone (McArthur, 1967). These anomalous thumbs have been described as a murderer’s thumb (Stecher, 1957), talpism (Coffin, 1964), spatulate, short, stubby, flat, wide, or clubbed (Rubinstein and Taybi, 1963). The nail can also be flat and short. The thumb may be hyperextensible. Usually, the range, of motion and opposition is limited.

Roentgenograms with the thumbs pressed flat show the distal phalanx to be short and wide. The deformity almost appears to be an attempt at duplication. At birth

Patients with the Rubinstein-Taybi syndrome are usually short. The characteristic facies consists of a beaked nose (Figure l), slightly malformed ears, a highly arched palate, an antimongoloid slant of the palpebral fissures, clinical hypertelorism, and heavy or highly arched eyebrows (Johnson, 1966). These children can have ocular problems such as strabismus, cataracts, glaucoma, colobomata, and refractive errors (Roy et al. 1968). In the hands and feet, in addition to the broad thumbs (Figure 2) and great toes (Figure 3), there can be clinodactyly of the fourth toe and the fourth and fifth fingers, flattening of the fingernails and hypoplasia of the toenails. The major impairment is mental retardation: these patients frequently have IQ’s below 50 (Padfield et al. 1968). There are associated cardiac anomalies, including patent ductus arteriosis, septal defects and more complex malformations (Sinette and Odeku, 1968). Reports of vertebral abnormalities, delayed descent of the testes, gastroesophageal reflux and kidney abnormalities are frequent.

The broadness of the thumbs appears to be mainly localised to the distal phalanx (Berg et al. 1966) and Received for pubbcation 20th August. 1986. Virchel E. Wood. M.D., Chief Hand Surgery Serwce Professor, Orthopedic Surgery. Loma Linda University, School of Medicine, - MC. Jack H. Rubinrtein, M.D., Professor of Pediatrics, University of Cincinnatt College of Medicine. Director, Umversity Affiliated Cincinnau Center for Develoomental Disorders.

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Fig. 1 The beaked nose is a common characteristic of the Rubinstein-Taybi syndrome. (Courtesy of Professor Dieter Buck-Gramcko).

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About 40% of the patients have a delta phalanx in the proximal phalanx of the thumb which causes the deviation of the distal phalanx; hence the term “hitch- hiker thumb” (Figure 4). This is a specific abnormality and is found in only a few syndromes. These include Apert syndrome (Figure 5), diastrophic dwarfism, the Rubinstein-Taybi syndrome, Pfeiffer syndrome (Pfeiffer, 1969) and Trisomy-D or Patau syndrome (Garcia et al. 1975). When a child is seen to have broad thumbs, broad toes, and a beaked nose, Rubinstein- Taybi syndrome should be considered.

Aetiology and Inheritance Most cases in the literature have been sporadic (Poznanski, 1984); however, autosomal recessive inheritance has been suggested (Der Kaloustian, 1972). The cause in unknown. A small chromosomal aberration seems to be the most likely cause (Temtamy and McKusick, 1978); however, no consistent cytogenetic abnormality has been demonstrated.

phalanx and involves born sort ussws anu Professor Dieter Buck-Gramcko).

the appearance may be more marked. Yet, as the child matures, there is often a hole or distal notch remaining in the distal phalanx. Although duplication has been seen frequently in the proximal and distal phalanges of the toes, we have never seen a true polydactyly of the thumb. Only one case had an associated polydactyly of the little finger.

Fig. 4 The clinical and roentgenographic finding of a child with a a & b hitch-hiker thumb. The proximal phalanx is a delta phalanx

and causes radial deviation.

about 24% of individuals has -_ 1-.___1 (Courtesy c

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Fig. 5 This child with Apert syndrome demonstrates a “hitch-hiker thumb”. (Courtesy of Dr. Adrian E. Flatt).

Only 14 black individuals have been reported to have the Rubinstein Taybi syndrome. Of these, nine had a delta phalanx in the thumb or great toe and duplication in the great toe, or both. Eight had all four extremities involved.

Associated problems The surgeon should be aware of several other unique problems of the Rubinstein-Taybi syndrome. Arrhythmias have been reported in one patient during anaesthesia (Stirt, 1981). It has been suggested that succinylcholine, with its propensity for altering cardiac rate and rhythm, might cause arrhythmias in these patients. Caution is advised when using relaxants and reversing agents. Children with Rubinstein-Taybi syndrome should also be considered to be at a high risk for aspiration during anaesthesic induction and emergence, and they should always have an endotracheal tube inserted for general anaesthesia.

The individual with the Rubinstein-Taybi syndrome may have an increased susceptibility to dermatophyte infections (Selmanowitz and Stiller, 1981) as well as to chronic paronychia of the fingernails and toenails (Der Kaloustian et al, 1972; Padfield et al, 1968).

Another important consideration is that these individ- uals have a tendency to keloid formation (Goodfellow et al. 1980; Kurwa, 1978; Rohlfing et al. 1971). This should always be considered when surgery is undertaken.

Clinical Material We reviewed the clinical descriptions, X-rays (when available), and follow-up letters related to the 530 cases reported in the literature. We also attempted to contact

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the operating surgeon of each surgical procedure performed on a thumb. In addition, a large amount of information about the Rubinstein-Taybi syndrome itself (Rubinstein, 1969) has been gleaned from this series.

Of the 530 cases, 245 (46%) were female and 285 (54%) were male. The sex difference was not significant. By an arbitrary definition of the syndrome, all of the children had broad thumbs. Some thumbs were broader than others, but size was not necessarily related to the degree of impairment. However, the degree of radial angulation determined whether these children had good functional opposition of their thumbs. In 182 patients, one or both thumbs angulated radially, with the distal phalanx falling off into the so-called “hitch-hiker position” (Figure 4a). An additional 222 individuals had no angu- lation, and in 126 cases we had inadequate information to determine whether the thumb was angulated or not. Of the cases in which the data were adequate, 45% had angulation of the thumbs. Thus, an estimated 34% to 45% of the entire series had severe radial angulation.

By far the most common finding was bilateral angulation (141 cases) (Figure 4b). Of the 41 cases of unilateral angulation, the right side was involved 30 times and the left side, 11. In this series, males with radial deviation predominated 110 to 72.

The angulated thumb has been described by names such as the hammerhead thumb, the hitch-hiker thumb and the viper-type proximal phalanx. The cause is a delta phalanx deformity of the proximal phalanx of the thumb (Figure 4b). No thumb showed ulnar deviation, and there were no thumbs with an associated complete polydactyly.

Among the cases for which information was available, 48 had a delta phalanx in the first toe ray, and of these, 33 were bilateral. The delta phalanx deformity in the foot was associated with bones other than the proximal phalanx: 35 cases had a delta deformity in the proximal phalanx, and 22 were bilateral. Four cases had a delta deformity in the distal phalanx, and three were bilateral. Eight of nine cases with a metatarsal delta bone were bilateral. About 24% of the children with broad toes with or without a delta phalanx had an angular deformity either in the medial or lateral direction.

When the proximal phalanx or the metatarsal had a delta deformity, there was often polydactyly in the ray. Polydactyly of the metatarsal occurred in only one case; of the proximal phalanx, 29 cases with 20 bilateral; of the distal phalanx, 41 cases with 24 bilateral; and of both the proximal and distal phalanges 20 cases with 13 bilateral. A polydactyly of the fifth toe was reported in 22 cases.

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Fig. 6 These delta phalanges of the proximal phalanx are approximated into what we term a “kissing delta phalanx”.

We found that if the delta phalanx involves the proximal phalanx of the great toe, and if there is duplication, the other phalanx is delta-shaped and the apices appear to be approximated into what we termed a “kissing delta phalanx” as shown in Figure 6.

Treatment for the hitch-hiker thumb Children with the hitch-hiker thumb are limited in their functional capabilities. They function with thumbs that appear to be shortened by the length of a phalanx (Figure 7). Opposition and grasp continue to be diminished in adults, but they can function in the everyday activities of life. Individuals with the Rubinstein-Taybi syndrome have been reported to live beyond the age of 60.

In our 530 cases, we found only one thumb that appeared to straighten as growth continued. It would seem that the hitch-hiker thumb is not going to correct itself in most cases, it does limit grasp, and it is a detriment to opposition.

The treatment of the hitch-hiker thumb is similar to the treatment for the defta phalanx (Wood and Flatt, 1977). The delta phalanx is so named because it is triangular or delta-shaped. The problem is however, that the epiphysis runs longitudinally instead of transversely. The abnormal epiptiysis surrounds the diaphysis of the phalanx like a staple (Carstam and Theander, 1975; Ogden et al. 1981). It has been labelled “longitudinally bracketed diaphysis” and “longitudinal epiphyseal bracket”. On a roentgenogram, the phalanx may appear like a circle or the letter D. This arrangement may cause the radial deviation to become progressively worse as growth continues.

Fig. 7 Individuals with a hitch-hikers thumb have a weak pinch. The thumb is effectively shortened the length of the distal phalanx.

In our review, we found 20 patients who had undergone some 53 surgical procedures for their thumbs (Table 1). One individual with Rubinstein-Taybi had undergone three operations to release the syndactyly in both hands. The age at operation ranged from 4 months to 11 years: the majority of cases were treated between the ages of two and four. Preoperative casting was used in at least three of the cases. Several operations produced no improvement and are not recommended: These were simple pinning, primary fusion, and simple capsulotomy.

TABLE 1

Surgery donefor thumb

Total number of Operations Total number of Patients Total number of Thumbs

Treatment of Delta Phalanx

53 20 35

Closing Wedge Osteotomy Opening Wedge Osteotomy Reverse Wedge Osteotomy Simple Pinning Arthrodesis IP Joint Resect Bracket & Fat Graft Revise Osteotomy

Treatment of Soft Tissue

Z-Plasty Capsulectomy Distal Based Skin Flap

14 9 4 4 2 1 1

15 2 1

Most of the surgical procedures were aimed at treating the delta phalanx. A closing wedge osteotomy was used in 14 cases, an opening wedge in nine, and a reverse wedge in four. One case had a fat graft applied after the bracket was released. Several soft tissue procedures were done: two capsulectomies, 15 Z-p&ties, and one distally-based flap.

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Opening Wedge

Fig. 8 An opening wedge osteotomy has been most often used for the treatment of the delta phalanx.

The recommended procedure for a delta phalanx has been an opening wedge osteotomy (Jones, 1964). Bone, usually from the iliac crest, is packed into the opening of the wedge and held with a K-wire (Figure 8). A Z-plasty usually becomes necessary because of the tightness of the contracted side, and sometimes a skin graft is needed to cover the open area.

A reverse wedge osteotomy has been described by Carstam (1975). In this procedure, the thumb is approached through a dorsal curved incision. A wedge of bone is excised, then reversed and put back in the place from which it came (Figure 9).

The third technique is simply to resect the bracket (Figure 10). Vickers (1984) suggests that one should then replace the isthmus with a fat graft.

The ideal solution would be simply to cut the bracket at an early age and let the thumb correct itself, but our experience with this syndrome is too limited to feel comfortable with such a simple procedure.

Another technique that has worked well is to remove a wedge of the bone and close the osteotomy. This works well if it is carefully done and if the bone is held properly closed with a K-wire (Figure 11). In our review of 14 such operations, 12 showed good results at follow-up ranging from 1 to 21 years. In six of these children, surgical treatment had spanned nine years.

Reverse Wedge

Fig. 9 Drawing and X-ray to illustrate the concept of a reverse a&b wedge osteotomy. (Courtesy of Dr. Graham Baker).

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The treatment of the soft tissues is important. The concave side of the hitch-hiker thumb is tightly contracted. The ligaments and soft tissues must be lengthened for the thumb to be straightened into proper position. The capsule, as well as the other soft tissues, may have to be released. Most often a Z-plasty will satisfactorily release the thumb, particularly when accompanying a closing wedge osteotomy; however, for an opening wedge osteotomy, it may be necessary to add a skin graft to cover the bone.

We reviewed the histories of 19 of the 20 patients who had had surgery of the thumb. Many had satisfactory cosmetic and functional results. The corrected thumbs had better opposition and a stronger grasp than did the thumbs on the other hand. In eight and possibly 11 of the 35 thumbs of these 19 patients, the deformity recurred. (In one case, the deformity was not fully corrected at the time of surgery. Further surgery should improve the results in this case).

Because the limited experience of any one hand surgeon is insufficient to evaluate the diversity of operations and the diversity of opinion regarding the Rubinstein-Taybi syndrome and the hitch-hiker’s thumb deformity, we propose a surgical programme that we believe to be the best. We recommend operating at the age of about one year, although anywhere up to the age of four seems satisfactory.

The increased likelihood of keloid formation and the possible increased risk of anaesthesia should be reviewed with the family. Pre-operative splinting and other non-

Fig. 10 The simplest treatment is to cut the bracket (This illustration was used in Green, D., ed, Operative Hand Surgery, 1st edition, Churchill Livingstone, 1982, for another purpose).

surgical methods are seldom useful in the treatment of this syndrome.

First, we treat the delta phalanx by a simple closing wedge osteotomy. We remove a small wedge, bring the bone together, and hold it with a K-wire. With this procedure, we have had to do a Z-plasty on the concave side to straighten the thumb. A skin graft to get closure has not been necessary. We have no objection to an opening wedge osteotomy, or to cutting the bracket and filling the area with fat. We also do not object to doing a reverse wedge osteotomy; however, all of these techniques entail more surgery and are technically more difficult. With the anaesthetic and infection risks in these children, the simplest procedure is the best.

If the thumb does not completely straighten after the first operation, we consider fusing the metacarpophal- angeal joint at about the age of ten. Even if the thumb shortens from the fusion, it is not a serious disability: any loss of function will be minimal,

If desired by the family, cosmetic improvement in the persisting soft tissue and bone enlargement should be considered when the patient is about ten years old. The epiphyseal growth potential can be destroyed, and the soft tissues can be debulked. Bone from the radial side may have to be removed, and the collateral ligament may have to be reconstructed. These procedures leave the important ulnar sensory side of the thumb intact. If the soft tissues are bulky, removing a wedge of skin and soft tissue from both sides of the phalanx can make the thumb thinner and smaller. If fusion is also necessary, it can be done at the same time.

Closing Wedge

Fig. 11 A closing wedge osteotomy appears to work best for the hitch-hiker thumb in the Rubinstein Taybi syndrome.

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Acknowledgments We would like to express our appreciation to the surgeons who were so kind to let us glean the information about their patients. Each surgeon was very helpful with operative reports, progress notes, pictures and X-rays. We wish to thank: Richard Goldburg, John Boswick, Ray Ashworth, James Richards, James Doyle, Graham Baker, Dieter Buck-Gramcko, R. W. Bright, Charles Price, Donald S. Blackwell, John Bolger, Harold Kleinert, Royce Lewis, Thomas Ferlic, Timothy O’Connel, Joseph Posch, Seymour Ziibler, J. Willis. We also wish to acknowledge all of the individuals who assisted in gathering and analyzing this information, translating articles, reviewing roentgenograms, and especially all of the families and professionals without whose co-operation this series could not have been possible.

This project was supported in part by Grant No. MCJ-tklO-912-20-1, awarded by the Bureau of He&b Care Delivew and Assitance. Maternal and Child Health. Public Health Service, DHHS and Grant No. ‘OODL70269/04, awarded by Administration On Developmental Disabilities, OHDS, DHHS.

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