Causes of secondary deformity after surgery to correct Wassel type IV-D thumb duplication

Secondary complications in Wassel II & IV thumb duplication: a comprehensive review of preventive measures

OBJECTIVES

Thumb duplication is one of the most challenging pediatric reconstructive hand surgeries. Wassel types II and IV are the most frequent, but also the most complex reconstructions as the duplication arises at the joint level. Ablation and reconstruction, the most widely used technique, aims at achieving a stable, well-aligned, mobile and esthetically acceptable thumb. The paucity of reliable surgical guidelines leads to high rates of suboptimal surgical outcomes. This review evaluated the various reconstruction techniques detailed in the literature and highlighted useful methods to prevent common secondary complications.

METHODS

A comprehensive PubMed and Embase literature search was made. Inclusion criteria were Wassel type II and/or IV, pediatric patients, and primary or secondary surgeries. Exclusion criteria were Bilhaut-Cloquet reconstruction and its modifications. Techniques were screened, collected and analyzed for the following secondary complications: instability, axial deformity, and contour deformity.

RESULTS

Thirty-two articles met the inclusion criteria and were reviewed. Postoperative instability was prevented by tightening the joint capsule by plication, advancement of the volar plate, or reconstruction of the collateral ligaments using a periosteal flap or the double-breasting technique. Axial deformity was prevented by arthroplasty, shaving a triangular portion of the metacarpal head, centralization of eccentric tendons, pulley reconstruction using flexor pollicis longus, or corrective osteotomies of the phalangeal or metacarpal bones using the wedge or oblique techniques. Limited range of motion was prevented by first webspace Z-plasty, and soft-tissue contouring was addressed by planned skin incisions and soft-tissue augmentation. Preoperative, perioperative and postoperative considerations, including splinting, imaging and immobilization, were also described.

CONCLUSION

Despite the ongoing advances and abundant knowledge in reconstructive strategies for thumb duplication, there are few studies that reviewed and analyzed the various reported options. This review provides physicians and trainees with guidance in surgical planning to prevent common secondary complications. Further research should focus on the development of standardized assessment tools, enabling reliable prospective comparative studies on thumb duplication reconstruction.

LEVEL OF EVIDENCE

IV.

Classification of radial polydactyly based on physical characteristics

BACKGROUND

Previous classifications in polydactyly of the thumb were by the level of duplication on radiography. This study aimed to develop a practical algorithm based on physical characteristics for treatment guidelines.

METHODS

The polydactylies were stratified using four physical characteristics: floating, symmetry, dominant side, and joint angulation/nail size. The algorithm identified the hypoplastic type and then stratified the polydactylies as symmetric and asymmetric. The asymmetric type was divided into ulnar dominant and radial dominant. The symmetric type was divided into adequate type and inadequate type. The prediction of treatments was studied retrospectively by the distribution of surgical procedures in 500 patients with 545 affected thumbs, by the new classification and the Wassel-Flatt classification.

RESULTS

Of the 545 polydactylies, 78 (14.5%) were categorized as the hypoplastic type, 369 (67.5%) as the ulnar-dominant type, 8 (1.5%) as the radial-dominant type, 70 (12.8%) as the symmetric adequate nail type, and 20 (3.7%) as the symmetric inadequate type. Treatments were excision and reconstruction in 403 polydactylies (73.9%), simple excision in 135 polydactylies (24.8%), and the Bilhaut-Cloquet procedure, ray amputation, and on-top plasty procedures were only performed in 7 polydactylies (1.3%). The distribution of surgical procedures was distinct among the new classification types and was similar among the Wassel-Flatt types.

CONCLUSIONS

The new classification stratified polydactylies by physical findings in a stepwise manner. Though surgical technical details are not included, this simple classification is useful for paediatricians and parents to understand how a surgical decision is made.

LEVEL OF EVIDENCE

Diagnostic Level IV.

Revision of residual deformities after primary surgery for Wassel-Flatt IV-D thumb duplication using a microsurgical free lateral great toe flap

We report the application and results of skin defect coverage using the free lateral great toe flap in revision surgery for residual postoperative deformities in Wassel-Flatt type IV-D thumb duplications. This retrospective study included five patients treated between June 2020 and September 2021 to correct angular deformity and repair the secondary skin defect. All the flaps survived. The patients were followed up for 8-12 months and all the reconstructed thumbs had a satisfactory appearance. The results of the Japanese Society for Surgery of the Hand scoring system were excellent in one patient, good in three patients and fair in one patient. The results of the Alignment, Ulnar and Radial stability, Range of motion and Aesthetical aspects (ALURRA) scoring system were good in four patients and moderate in one patient.Level of evidence: IV.

Modified Wassel-Flatt Type III Radial Polydactyly: Subtypes and Their Outcomes

PURPOSE

We aimed to subdivide modified type III radial polydactyly and evaluate the applied surgical procedures and outcomes according to the subtypes.

METHODS

This study included 32 thumbs of 32 patients treated for modified Wassel-Flatt type III radial polydactyly from March 2008 to December 2018. Each patient was subclassified into parallel, divergent, and convergent types according to the alignment of the duplicated digit. The parallel type was further divided according to the treatment method applied. The parallel A group comprised patients treated with reconstructing the radial collateral ligament of the interphalangeal (IP) joint after removing only the distal phalanx and preserving the proximal phalanx of the extra digit, and the parallel B group comprised patients treated with excision of the extra digit at the bifurcation site of the proximal phalanx. We evaluated the Japanese Society for Surgery of the Hand scores and radiographic angulation of the IP and metacarpophalangeal joints at a mean follow-up of 38 months.

RESULTS

Fourteen cases were parallel type (6 and 8 in the parallel A and B groups, respectively), 14 were divergent type, and 4 were convergent type. Patients in the parallel A group had significantly better IP and metacarpophalangeal joint angulation and Japanese Society for Surgery of the Hand scores than those in the parallel B group. Patients in the parallel A group had significantly better Japanese Society for Surgery of the Hand scores than those in the divergent and convergent groups.

CONCLUSIONS

Reconstructing the radial collateral ligament of the IP joint after removing only the distal phalanx and preserving the proximal phalanx of the extra digit was associated with better outcomes than the excision of the extra digit at the bifurcation site in the parallel type cases. The parallel type treated with proximal phalanx preservation and ligament reconstruction had better clinical outcomes than other types of modified Wassel-Flatt type III radial polydactyly.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Prediction of Surgical Outcomes of Radial Polydactyly From the Wassel-Flatt Type and Symmetry of Duplication

BACKGROUND

The Wassel classification is commonly used for cases of radial polydactyly but has not been used to predict surgical outcomes. This study aimed to investigate the predictive factors of surgical outcomes using the Wassel type and symmetry of duplication.

METHODS

Forty-five patients with 47 radial polydactylies were reviewed using the Japanese Society for Surgery of the Hand (JSSH) scores 4.6 years after minor thumb excision and reconstructive surgery. The symmetry index was defined as the metaphyseal width ratio of the minor thumb to the dominant thumb. The relationships between the JSSH scores and operation age, sex, side, follow-up duration, Wassel type, symmetric index, divergent angle, and joint angulation were analyzed by linear regression.

RESULTS

The mean JSSH score of the 47 thumbs was 18.3 points (range, 15-20). Five thumbs had fair or poor outcomes (scores <17), all of which were Wassel type IV. The hypoplastic type had a better JSSH score (19.4) than other Wassel types. The symmetric index had a negative relationship with JSSH scores, especially for Wassel type IV (r=-0.68, P =0.001). Linear regression revealed that the symmetric index was the only independent factor significantly associated with JSSH scores among Wassel type IV polydactylies ( P <0.05). The receiver operating characteristic curve suggested a symmetric index <0.74 could predict good or excellent outcomes.

CONCLUSION

The symmetry of the 2 duplicated thumbs is an important factor for surgical outcomes. The Wassel type IV polydactylies with a symmetric index >0.74 are at greater risk of fair or poor outcomes after excision and reconstruction, and further studies are warranted to confirm whether the Bilhaut-Cloquet procedure is a good choice.

LEVEL OF EVIDENCE

Level IV-Case-control study.

Use of the duplication range concept for understanding morphology and predicting prognosis in thumb polydactyly

This study systematically and comprehensively analysed 129 thumb polydactylies in 122 patients using a duplicating range concept based on the level of skin and skeletal bifurcation. Numerical levels were defined along the longitudinal axis of the ulnar thumb duplicate from distal to proximal: level 0 (thumb tip) to level 6 (carpometacarpal joint). The relationships between duplication range and morphological parameters were evaluated. Nail asymmetry was associated with skin bifurcation levels 0 to 2. Proximal phalangeal asymmetry and interphalangeal joint deviation, associated with skin bifurcation levels were assigned scores of 1 to 2.5 and 1 to 2, respectively. Metacarpophalangeal joint deviation had a bimodal distribution, at levels 1.5 and 4 of the longitudinal axes. Morphological similarity was found in patients with the same duplication range. The duplication range concept could potentially improve our understanding of morphology variation and predicting prognoses in thumb polydactyly.Level of evidence: III.

When Is Primary Metacarpal Corrective Osteotomy Recommended in Patients with Flatt Type IV Radial Polydactyly?

BACKGROUND

The aim of this study was to determine when primary metacarpal corrective osteotomy is recommended in patients with Flatt type IV radial polydactyly.

METHODS

A total of 78 patients with Flatt type IV radial polydactyly were included. The authors performed metacarpal osteotomy if the angulation of the metacarpophalangeal joint was not correctable by the intraoperative radial stress test. The authors measured the metacarpal deviation angle of the thumb in simple posteroanterior radiographs. The clinical outcomes were assessed using Japanese Society for Surgery of the Hand evaluation total score and the metacarpal deviation angle correction angle. These outcomes were compared between the patients who underwent metacarpal osteotomy and those who did not. Of the patients who did not undergo metacarpal osteotomy, the relationships between preoperative metacarpal deviation angle and the metacarpal deviation angle correction angle were formulated using segmented linear regression analysis.

RESULTS

There were no significant differences in the demographic features and the value of preoperative metacarpal deviation angle between the two groups. However, the metacarpal deviation angle correction angle and Japanese Society for Surgery of the Hand evaluation total score were significantly higher in the patients who underwent metacarpal osteotomy. The segmented linear regression analysis demonstrated a breakpoint, indicating that the soft-tissue procedure alone does not sufficiently correct the metacarpal deviation angle. For the postoperative metacarpal deviation angle to be 5 degrees, the preoperative metacarpal deviation angle was calculated as 10.8 degrees.

CONCLUSION

If the preoperative metacarpal deviation angle is greater than 10.8 degrees, metacarpal osteotomy can be considered even in patients with correctable metacarpophalangeal joint by intraoperative radial stress test.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Soft tissue abnormalities in Wassel Type VI radial polydactyly: a detailed anatomical study

Wassel VI radial polydactyly is associated with metacarpal adduction and radial deviation of the metacarpophalangeal joint of the ulnar duplicate. The soft tissue abnormalities responsible for these deformities were characterized using preoperative multi-planar three-dimensional ultrasound and intraoperative observation in four patients. In all patients, the abductor pollicis brevis and superficial head of the flexor pollicis brevis inserted into the radial first metacarpal, whereas the adductor pollicis and deep head of the flexor pollicis brevis inserted into the ulnar thumb. Aberrant location of the flexor pollicis longus and absence of the A1 pulley system was associated with severe radial deviation. An additional superficial thenar muscle along the ulnar metacarpal was associated with minimal metacarpal adduction. Uneven forces on the ulnar duplicate could be associated with these characteristic deformities and joint instability. Knowledge of these abnormalities allows better planning of surgery and further insight into this rare radial polydactyly configuration.Level of evidence: II.

Modified method for reconstruction of thumb abduction function in children undergoing surgical treatment of thumb duplication

PURPOSE

This study was performed to evaluate a modified method of reconstructing the thumb abduction function in children undergoing surgical treatment of thumb duplication.

METHODS

This retrospective study included 33 children (38 thumbs) with Wassel type III to VII thumb duplication who underwent excision of the polydactylism and osteotomy of the preserved thumb. Among them, 16 children (19 thumbs) underwent reconstruction of the attachment of the articular capsule and collateral ligament of the metacarpophalangeal joint, abductor pollicis brevis and flexor pollicis brevis by the anchor technique (Group A), while 17 children (19 thumbs) underwent suturing the attachment of the above-mentioned soft tissues to the periosteum (Group B). All children were followed up for six years after surgery. The appearance, function and joint stability of the preserved thumb were compared between the two groups; the bone alignment and development were observed.

RESULTS

The deformity rate of preserved thumbs and the positive rate of lateral stress test were significantly lower in Group A than B (p < 0.05). The modified Tada score and the distance of first web were significantly higher in Group A than B (p < 0.05). Flexion, extension, adduction, abduction and palmar movement of the thumbs were good; bone alignment and development were good and no osteophyte or anchor shadow was left in the preserved thumbs in Group A.

CONCLUSION

Reconstruction of the abduction function using the anchor technique is effective in children undergoing surgical treatment for Wassel type III to VII thumb duplication and it may be superior to the conventional technique.

LEVEL OF EVIDENCE

III.

What's New in Congenital Hand Surgery

BACKGROUND

Congenital conditions of the hand and upper extremity are a frequent source of consultation among pediatric orthopaedists and hand surgeons. Advances in the fields of molecular biology and genetics have helped to better understand some of these conditions and redefine previous classification systems. New outcome measurement tools have been used to assess surgical results and have brought into focus a different aspect of the patients' experience.

METHODS

We searched PubMed database for papers related to the treatment of congenital hand anomalies published from January 1, 2015 to October 31, 2018. The search was limited to English articles yielding 207 papers. Three pediatric hand surgeons selected the articles based upon the criteria that the topic was germane, the article fell under the subheadings within the manuscript, and the conclusions were meaningful.

RESULTS

A total of 40 papers were selected for review, based upon their quality and new findings. Research articles with significant findings were included for syndactyly, symbrachydactyly, cleft hand, polydactyly, radial longitudinal deficiency, congenital radio-ulnar synostosis, and macrodactyly.

CONCLUSIONS

Our knowledge of the embryology and pathophysiology of congenital upper extremity conditions continues to evolve. Functional assessments combined with patient and parent-reported outcomes have our understanding of the results following surgical procedures. Further research and standardization of our scientific data will provide better answers and higher quality of evidence.

LEVEL OF EVIDENCE

Level V-literature review and expert opinion.

[Recent progress in research of congenital polydactyly]

Surgery is still the main treatment for congenital polydactyly, and the aim of surgical reconstruction is to obtain a thumb with excellent function and appearance. A systematic assessment of polydactyly is required prior to surgery, including bone stress lines, joint deviation, joint activity and joint instability, size and development of finger and nail. Bone shape, joint incongruency, and abnormal tendon insertions must be corrected completely, in order to obtain good function and to avoide secondary surgery. Bilhault-Cloquet procedure can reconstruct the size of the finger and nails. Fine manipulation can improve the postoperative nail deformity, so that the reconstructed nail reaches a satisfactory aesthetic score.

POSTOPERATIVE RETROSPECTIVE ANALYSIS OF THE TREATMENT OF DUPLICATED THUMB

OBJECTIVE

To evaluate postoperative epidemiological and functional factors in patients operated to treat duplicate thumb.

METHODS

This retrospective case series evaluated 20 patients (23 thumbs) treated from January 2012 to December 2016 at our service. Epidemiological and clinical factors were studied, including Tada score.

RESULTS

Of the 34 children who were treated surgically, only 20 appeared for the functional evaluation and were included in the study. Of the operated cases, 60% were Wassel type 4. All evaluated cases had good functional results (Tada score ≥5, mean score: 6.65). The most frequently used surgical technique was resection of the radial thumb with reconstruction of the radial collateral ligament (47.8% of cases).

CONCLUSION

Surgical correction of duplicated thumb yields good results, as long as attention is paid to abnormalities in bones, ligaments, and tendons. Level of Evidence IV; Case series.

The anatomy of Wassel type IV-D thumb duplication

We describe Wassel type IV-D thumb duplication anatomy after surgery on 11 affected children (12 hands, seven boys (eight hands) and four girls). We studied the structure and course of the flexor pollicis longus tendon and its action at the joint. Four patients had secondary deformity associated with an absent A2 pulley and a tendon that clung to the radial side of a small thumb. In patients with primary deformity, the flexor tendon sheath became membranous in the A2 area and attached to neighbouring sites on the opposite side of the proximal phalanx. In the proximal A2 area, the tendon divided - one division attached on the ulnar side of the distal phalanx base; the other, the base of the radial side. There was slight ulnar angulation of the distal phalanx on the radial portion of the duplication and slight ulnar angulation on the radial portion.

LEVEL OF EVIDENCE

V.