Reduction osteotomy for triphalangeal thumb: an 11-year review

Surgical Reconstruction for the Triphalangeal Thumb

The triphalangeal thumb poses a complex reconstructive challenge to the congenital hand surgeon due to its rarity and variable anatomy. We discuss the available evidence, reporting clinical characteristics and outcomes of surgical reconstructive procedures of triphalangeal thumb alongside a representative case. The congenital hand surgeon must approach each patient with triphalangeal thumb individually to optimize the use of available tissues to maximize functional and aesthetic outcomes.

Triphalangeal Thumb Reduction Osteotomy Through a Versatile Spiral Approach

Triphalangeal thumb (TPT) is a congenital condition characterized by the presence of an additional phalanx. Variable degrees of thumb deformity, malalignment, and excessive length are common features. Impairment of hand function has been reported with TPT probably secondary to anomalistic long thumb incompatible with fine hand skills. Abnormal thumb appearance moreover represents a major psychological concern from patient's perspective. Both removal of the extra phalanx and phalangeal reduction osteotomy with resection of the unhealthy extra interphalangeal joint are established methods for correction of the associated excessive thumb length. In our experience, however, previous surgical approaches have not been able to sufficiently reduce the skin and soft tissue surplus, which exists after reduction osteotomy through classic circular incisions. We thus feel that conduction of TPT reconstruction through a spiral incision provides a safe and generous anatomic exposure required for simultaneous reduction of skeletal and soft tissue components.

Outcome of two types of surgical correction of the extra phalanx in triphalangeal thumb: is there a difference?

The surgical strategy of treatment of the opposable triphalangeal thumb is correction of the radio-ulnar deviation, reduction of the additional length and joint stabilization. The commonest procedures are: (1) removal of the extra phalanx and stabilization of the remaining joint; and (2) a combined reduction osteotomy with resection of the distal joint followed by arthrodesis. We treated 20 patients (33 hands). In 17 hands the extra phalanx was removed, and in 16 hands we used the combined osteotomy procedure of distal joint removal and arthrodesis. None of the patients in either group had an unstable interphalangeal joint. The mean radial or ulnar deviation in the interphalangeal joint was 5° degrees and 9°, respectively. Mean active flexion in the interphalangeal joint was 35° and 46°, respectively, in the two groups. Results for both procedures are similar, for both objective measures and self-rated function and activities of daily living. Either surgical approach seems reliable.Therapeutic, Level of evidence: Level III.

Results of Treatment of Delta Triphalangeal Thumbs by Excision of the Extra Phalanx

BACKGROUND

We examined the long-term results of treatment of delta triphalangeal thumbs by excision of the delta ossicle alone with respect to range of motion (ROM), pain, and angulation at the interphalangeal (IP) joint.

METHODS

We retrospectively reviewed charts to identify patients who had Woods type I delta triphalangeal thumbs and underwent treatment by excision of the extra ossicle. Patients with >2 years' follow-up were then brought in for examination and radiographs.

RESULTS

We identified 21 thumbs in 14 patients. All patients with bilateral thumb involvement, except 1, had them treated at the same surgery. The average age at surgery was 22 months (range, 5 to 69 mo). Preoperatively, 2 patients had tip radial angulation, averaging 53 degrees. The other 19 thumbs were deviated tip ulnarly with an average preoperative angulation of 40 degrees (range, 20 to 85 degrees). All patients had pinning of the IP joint for an average of 4.5 weeks (range, 3 to 9 wk), and 14 thumbs had collateral ligament repair. We obtained follow-up data >2 years on 14 thumbs in 10 patients. The average follow-up was 6.7 years (range, 2 to 17 y). Average ROM at final follow-up was <-4-degree extension (range, -20 to 0 degrees) to 56-degree flexion (range, 30 to 82 degrees). Average clinical angulation was <1 degree (range, 0 to 10 degrees) and the average radiographic angulation was 7 degrees (range, 0 to 25 degrees). No degenerative changes were noted. There were no complaints of pain and 1 patient had persistent IP instability. No other surgeries had been performed on the affected thumbs and there were no other complications.

CONCLUSIONS

Delta triphalangeal thumbs treated by excision of the extra ossicle can be expected to yield good long-lasting results with acceptable thumb IP ROM and no pain. Clinical appearance of the thumb with regard to angulation tends to be superior to radiographic findings. We prefer this method in treating Woods type I delta triphalangeal thumbs.

LEVEL OF EVIDENCE

IV.

Evaluation of function and appearance of adults with untreated triphalangeal thumbs

PURPOSE

Triphalangeal thumb is a congenital malformation characterized by an additional phalanx of the thumb. Although surgical treatment of this condition is common practice, in the past this was not generally advised. Therefore, a population with an untreated triphalangeal thumb is still present. The purpose of this study is to compare function and appearance of adults with an untreated triphalangeal thumb to a normal population.

METHODS

Twelve adults with 23 hands with an untreated triphalangeal thumb, unilateral or bilateral, were examined using objective measurements (thumb movement, joint instability, pain, and strength) and subjective measurements (visual analog scale; Disabilities of the Arm, Shoulder, and Hand questionnaire; and Short Form 36 health survey).

RESULTS

Objective measurements showed no limitations in range of motion or in grip and pinch strength. No joint instability was found in the interphalangeal joints. Five thumbs had instability in the metacarpophalangeal joint. Strength of the thumb in anteposition was diminished to 64% compared to a normal population. Opposition was diminished to 62%, and metacarpophalangeal joint flexion strength was diminished to 61%. The patients scored lower compared to a normal population for the domain of social functioning in the Medical Outcome Study 36-item short form health survey; the Disabilities of the Arm, Shoulder, and Hand questionnaire showed no differences. Visual analog scale scores for appearance of the thumb were scored low (2.2 of 10) by the adults, in contrast to visual analog scale scores for function (7.7).

CONCLUSIONS

The examined group of adults with an untreated triphalangeal thumb had adequate thumb movement. Thumb strength was diminished for all specific thumb functions (anteposition, opposition, and thumb flexion), as low as 55%, compared to normal controls. Self-rated scores indicate that patients perceived their functionality as good. The appearance, however, was rated much lower, implying a dislike of the thumb by the patients. This indicates that the main impact of an untreated triphalangeal thumb in daily functioning might not be the diminished function but rather the dissimilar appearance.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The effect of the epiphyseal growth plate on the length of the first metacarpal in triphalangeal thumb

PURPOSE

Triphalangeal thumb is characterized as a congenital difference of the thumb with an extra phalanx. Additional thumb length is attributed mostly to the extra phalanx. The influence of the epiphyseal plate positions on growth in congenital hand anomalies is unclear. The purpose of this article was to compare the length of the first metacarpal in triphalangeal thumbs with the length of the same bone in normal thumbs and to investigate the influence of the often aberrant metacarpal epiphyseal plates on the length of the triphalangeal thumb metacarpal during growth.

METHODS

The positions of the epiphyseal plate and the relative length of the first metacarpal were examined retrospectively in 37 patients with triphalangeal thumb. Ratios of the measurements were calculated (metacarpal II/metacarpal I) and compared with a normal population. Subjects were divided into 3 groups based on the position of the epiphyseal plate (double, proximal, distal).

RESULTS

The distally placed growth plate was the most common variety, present in 22 of patients, followed by the proximal position in 14, and double epiphyseal plates in 6. All ratios of patients with triphalangeal thumb were significantly smaller than those of a normal population, indicating a longer first metacarpal in this condition. First metacarpals in triphalangeal thumb with double epiphyses grew disproportionately more than those of a normal population, whereas those with distal epiphyses grew disproportionately less than normal. First metacarpals with proximal epiphyses grew at the same rate as normal first metacarpals.

CONCLUSIONS

In this study population the most common growth plate location was distal whereas the most common location in the normal population is proximal. The different positions of the epiphyseal plates correlate with growth differences in patients with triphalangeal thumb.

Abnormal triangular epiphysis causing angular deformity of the thumb

PURPOSE

To present a triangular-shaped abnormal secondary ossification center of the distal phalanx causing angular deformity of the thumb and the surgical outcome of corrective closing-wedge osteotomy for this deformity.

METHODS

We treated 6 patients with abnormal triangular epiphysis in the distal phalanx of the thumb, including 3 bilateral cases. The average age was 43 months and there were 2 boys and 4 girls. Of the 9 thumbs intraepiphyseal closing-wedge osteotomy was performed in 5 and proximal phalangeal closing-wedge osteotomy was performed in 4. We measured the deformities in degrees of angulation and the range of motion of the interphalangeal (IP) joint. The average duration of the follow-up period was 27 months after the surgery.

RESULTS

Preoperative angular deformity of ulnar deviation averaged 30 degrees , which was reduced to an average of 12 degrees after osteotomy at the last follow-up assessment. All osteotomies healed and there was no evidence of physeal or articular damage. Interphalangeal joint range of motion did not decrease after surgery in all cases. Patients and parents were satisfied with the results of the surgery, although mild deformity persisted in the interphalangeal joint when in the flexed position after proximal phalangeal osteotomy.

CONCLUSIONS

Abnormal triangular epiphysis causing angled thumb is different from delta bone and can be treated with either intraepiphyseal or proximal phalangeal closing-wedge osteotomy. The intraepiphyseal procedure, however, could achieve better deformity correction regardless of the interphalangeal joint position.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level IV.

Triphalangeal thumb without associated abnormalities: clinical characteristics and surgical outcomes

Thirty-four triphalangeal thumbs of 23 patients, who had no associated anomaly in their ipsilateral hand, were reviewed to clarify the characteristics of an isolated triphalangeal thumb and its surgical outcome. There were 13 type 1 thumbs, 21 type 2 thumbs, and no type 3 thumbs. The existence of an accessory phalanx caused ulnar bending at the interphalangeal joint. Thirteen type 1 thumbs were operated on by excising an accessory phalanx. Corrective osteotomy at the epiphysis was performed on four type 2 thumbs, and partial excision of the epiphysis was performed on 11 type 2 thumbs. At follow-up examination, the average interphalangeal joint motion was 54 degrees in type 1 thumbs and 53 degrees in type 2 thumbs. More than 10 degrees of lateral bending remained in one type 1 thumb and six type 2 thumbs. Good results were observed when an early excision of the accessory phalanx with a securing collateral ligament was performed on type 1 thumbs. For type 2 thumbs, partial excision of the epiphysis provided relatively better correction than osteotomy. For good adaptation of interphalangeal joints, surgery should be performed when the patient is between the ages of 1 and 2, when the epiphysis is visible on x-rays.

Opposable triphalangeal thumb: clinical features and results of treatment

The clinical features of opposable triphalangeal thumb were examined in 15 patients (23 hands). Triphalangeal thumb appeared as an isolated anomaly in 16 hands and in combination with cleft hand in 7 hands. Polydactylous changes in the distal phalanx were frequently observed in these hands and in the opposite thumbs in unilaterally affected cases. Opposable triphalangeal thumb seemed to have formed as a result of incomplete fusion of the duplicated distal phalanges or fusion of the thumb and index finger. Twelve hands in ten patients were treated surgically and followed for an average of 6.5 year. Nine hands were treated by removal of the accessory phalanx, and good results were obtained in all except one. Removal of the accessory phalanx seems to be a simple and reliable treatment for opposable triphalangeal thumb in young children.