An Individualized Approach to Surgical Reconstruction for Lateral Polydactyly of the Foot with an Emphasis on Collateral Ligament Reconstruction:

Novel Finding of an Excess Bone in Postaxial Polydactyly of the Foot

Background

Postaxial polydactyly is a common congenital foot anomaly. However, the severity of the anomaly varies from simple cases with only soft tissue duplication to complex cases with bone and joint disorders. In our clinical practice, we found a new morphological anomaly of postaxial polydactyly. We encountered several cases of postaxial polydactyly with bone fragments located between the fourth and fifth toes. The bone fragments were independent of the joint cavity. The mechanisms underlying its development remain unknown because it is a novel disorder. In the present study, we investigated the characteristics of the excess bone to formulate an embryological hypothesis.

Methods

We examined the frequency and trends in the occurrence of excess bone using data from photographs and radiographs of these cases. An example of a disorder similar to excess bone is mosaic-like alignment, as reported by Iba et al. We also compared the characteristics of the mosaic-like alignment with those of the excess bone. Based on these data and existing embryological knowledge, we hypothesized the origin of the excess bone.

Results

Excess bone and mosaic-like alignments showed different characteristics. Therefore, both were considered completely different disorders. We hypothesized that excess bone was caused by damage to the interdigital ectoderm immediately before interdigital programmed cell death.

Conclusions

We encountered a new form of postaxial polydactyly. This can be a factor influencing the treatment strategy because it can affect alignment and stability.

Morphologic Changes in Postaxial Polydactyly of the Foot: A Standardized Quantitative Analysis Using the Watanabe-Fujita Classification

BACKGROUND

Postaxial polydactyly of the foot is one of the most common congenital abnormalities. A wide forefoot, short toe, and lateral joint deviation are associated with aesthetic and functional outcomes. This study used the Watanabe-Fujita classification to characterize the preoperative and postoperative skeletal morphology of postaxial polydactyly of the foot.

METHODS

This retrospective study included 42 patients (51 feet) with postaxial polydactyly treated at age 1 year. Radiographs taken at ages 0 and 3 to 4 years were used for morphologic analysis. The length of the reconstructed toe, the distance between the fourth and fifth metatarsals, and joint deviation angles were measured. The length measures were standardized using the length of the third metatarsal. Morphologic characteristics were compared based on the Watanabe-Fujita classification at ages 0 and 3 to 4 years. Long-term outcomes were also evaluated in patients followed up for longer than 6 years.

RESULTS

The fifth-ray proximal phalangeal subtype had the shortest toe length both at ages 0 and 3 to 4 years. Proximal phalangeal joint lateral deviation improved postoperatively in 78% of patients with the fifth-ray middle phalangeal subtype, regardless of reconstruction type. There was no significant change in proximal phalangeal joint deviation between ages 3 to 4 years and 7 years or older. A residual metatarsal was associated with lateral metatarsophalangeal joint deviation and a wide intermetatarsal distance, and required revision surgery.

CONCLUSIONS

Morphologic changes of postaxial polydactyly of the foot were successfully characterized using the Watanabe-Fujita classification. This classification could be useful for planning surgical strategies and anticipating morphologic outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Reconstruction of polysyndactyly of the fused fifth toe with the fourth toe

Polysyndactyly of the fused fifth toe with the fourth toe is a common subtype of postaxial polydactyly. The aim of the study was to present an operative technique for cosmetic improvement and reconstruction of polysyndactyly of the fused fifth toe with the fourth toe. We retrospectively reviewed the details of 22 patients with postaxial polydactyly treated from January 2018 to May 2021. The operation involved medial toe excision and web space reconstruction using a dorsal rectangular flap without skin grafting and simultaneous correction of a valgus deformity by chondroplasty and soft tissue balancing without an osteotomy. The web shape, scar, and aesthetic outcomes were evaluated on the criteria of the D'Arcangelo, Vancouver Scar Scale score, and satisfactory questionnaire, respectively. The patients were followed up for 7-43 months. At the last follow-up, valgus deformity was completely corrected without recurrence. On the basis of the criterion of D'Arcangelo, the height and width of the webs were good in 24 of the feet, fair in four of the feet, and poor in none of the feet. The mean Vancouver Scar Scale score was 1.55. All parents and patients were satisfied with the appearance and function. The described medial toe excision technique and reconstruction of the web space without a skin graft corrected the valgus deformity and were able to satisfy functional and cosmetic requirements.

Congenital Lower Extremity Anomaly Pathology and Reconstruction: A Review of the Literature

SUMMARY

With the advent of the subspecialty of orthoplastic surgery, there has been a greater involvement of plastic surgeons in limb reconstruction, congenital anomalies, and salvage procedures. Understanding embryology helps plastic surgeons better understand how to reconstruct lower extremity congenital defects and how development of the lower limb affects what can be done to reconstruct the adult lower limb. There is significant discussion in the literature regarding embryology and development of craniofacial structures and the upper extremity; however, the development of the lower limb remains largely unexplored. This review aims to elucidate the embryologic development of the lower limb, congenital anomalies that may present to the plastic surgeon, and reconstructive options.

Surgical Procedures Based on the Arthrographic Findings of the Fifth MTP Joint With Proximal Phalanx Duplication in Postaxial Polydactyly of the Foot

Radiographic findings in several atypical cases of postaxial polydactyly of the foot do not provide sufficient information to assess the cartilaginous structures or duplicated digit connections at the MTP joint. The purpose of this study was to demonstrate the surgical procedures using arthrography for the cartilaginous structures of the MTP joint in postaxial polydactyly of the foot. We performed arthrography in 7 feet of 7 patients with postaxial polydactyly of the foot in which duplication of the proximal phalanx was observed at the fifth MTP joint on the basis of radiographic evaluation. The average age at surgery was 13.5 months and average duration of postsurgical follow-up was 36 months. Individual surgical procedures were confirmed or modified during the operation by reference to the arthrographic findings. Radiographic and arthrographic findings were assessed in relation to the findings from direct observation of the cartilaginous structures at surgery. Postoperative malalignment, functional disturbance and pain in the reconstructed toe were evaluated. The arthrographic findings provided different forms of cartilaginous structures that could be categorized in 4 types, and reflected the cartilaginous connection visualized at surgery that could not be detected on radiographs in each case. No cases revealed any deformities, functional disturbance, or pain in the reconstructed toe after surgery. The parents' evaluation in each case was "very satisfied" or "satisfied." The arthrographic findings provided additional information regarding variations in the cartilaginous structures of the fifth MTP joint and for determining individual surgical procedure for postaxial polydactyly of the foot.

Surgical Outcomes and Predictive Factors of Medial Toe Excision for Polysyndactyly of the Fifth Toe

BACKGROUND

We aimed to report surgical outcomes and analyze prognostic factors of medial toe excision for polysyndactyly of the fifth toe.

METHODS

We reviewed the details of 139 consecutive patients who underwent surgery for postaxial polydactyly of the foot from 2009 to 2018. Among these, 83 patients (90 feet) with polysyndactyly of the fifth toe, treated by medial toe excision (between the duplicated toes) and reconstruction of the fourth web space using a dorsal rectangular flap, were included. The toe alignment and stability were restored by chondroplasty and soft tissue balancing without an osteotomy. A full-thickness skin graft was performed in 52 feet. The mean age at surgery was 27.1 ± 17.5 months and the mean duration of follow-up was 42.8 ± 24.9 months.

RESULTS

At the last follow-up, a relatively small size of the reconstructed toe was observed in 19 feet (19/90, 21.1%). Proximal duplication level (metatarsal or proximal phalanx type) and preoperative hypoplasia of the remaining toe were related to the small postoperative size. Valgus deformity of the remaining toe was observed in 2 feet (2/90, 2.2%). We observed 17 cases with delayed healing or early postoperative wound infection. Among these, 7 cases (7/90, 7.8%) showed postoperative thickening or advancement of the web, which was not observed in cases without wound problems. No cases had functional disturbance or pain.

CONCLUSION

The overall surgical outcomes were satisfactory without an osteotomy. Patients with a proximal duplication level or preoperative hypoplasia of the remaining toe should be informed of its possible small size postoperatively.

LEVELS OF EVIDENCE

Level IV, retrospective case series.

Lower extremity postaxial polydactyly: Current literature status and future avenues

BACKGROUND

Despite lower extremity polydactyly (LEP) representing the most common congenital foot anomaly with functional and psychosocial implications, the literature is devoid of comprehensive, synthesizing reviews. The purpose of the current review is to identify an evidence-based approach to guide clinical management and shed light on reported functional and esthetic outcomes for postaxial polydactyly.

METHODS

A scoping systematic review of primary clinical studies was performed. Baseline patient characteristics, diagnostic, and surgical approaches were recorded. Main outcomes included immediate postoperative pain, infections, callouses, scar cosmesis, residual deformities, and difficulty with shoe-wear or mobility. A qualitative synthesis of outcomes was performed, and a therapeutic algorithm was developed.

RESULTS

Nine primary studies were identified representing 375 cases of LEP; mean age was 28.8 months (range: 20-40.6 months), and mean follow-up: 42.7 months (range: 1 month-41 years). Ray dominance and the presence of syndactyly were identified as the most important factors for surgical planning; age at surgery was insignificant. A lateral incision approach was used in 78% of cases. Postoperative callouses occurred in 22.1% of cases, infections in 2.5%, and intermittent pain in 11.9%. Significant issues with shoe-wear or mobilization and esthetic residual deformities were reported for 0.78% and 41.2% of cases, respectively. The incidence of residual valgus was 10.6%.

CONCLUSION

LEP is most commonly managed with excision of the non-dominant ray and carries excellent long-term functional outcomes, as presented herein. Numerous techniques are discussed to minimize the risk of esthetic sequalae, although the presence of residual valgus remains a concern. A therapeutic algorithm is proposed for the optimal management of LEP.

Case-control study of the treatment of postaxial polysyndactyly of the foot: Comparison of surgical results after removal of the fifth or sixth toe

Background

In postaxial polysyndactyly of the foot, the choice of which toe to excise is controversial. It is often treated by resection of the fifth toe to save the lateral neurovascular bundles of the sixth toe. However, the sixth toe is often short and laterally deviated, which may require wedge osteotomy, potentially shortening the phalanx and compromising circulation. This study outlines an individualized method to spare the length and axis of the fifth toe in polysyndactyly with a short and deviated sixth toe.

Methods

We retrospectively analyzed 38 patients who underwent surgery between 2006 and 2019. The fifth toe was spared in 18 cases, and the sixth toe in 20 cases. The ratios of the forefoot width, angle difference, and toe length were compared between the affected and unaffected sides postoperatively. Complications and subjective judgments on cosmetic results were recorded and compared.

Results

No significant between-group differences were observed for sex, age at surgery, or the follow-up period. The forefoot width ratio did not significantly differ between the groups. However, the angle difference and toe length ratios showed significantly better results in the fifth toe-spared group than in the sixth toe-spared group (P<0.05 and P<0.01, respectively). There were no cases of impaired circulation, and subjective evaluations revealed satisfactory results in the fifth toe-spared group.

Conclusions

In cases with short and deviated sixth toes, sparing the fifth toe is an effective method of cosmetic treatment. The surgical results were satisfactory, with an improved appearance and no residual deformities.

Midterm and Long-term Follow-up After Surgical Reconstruction for Lateral Polydactyly of the Foot With Mosaic-like Alignment of the Phalanx Bones

BACKGROUND

The phalanx bones in several cases of lateral polydactyly of foot revealed complicated alignment with radiographic findings revealing medial-protrusion and lateral deviation of the middle phalanx. We previously defined such cases as showing "mosaic-like alignment" and demonstrated favorable postoperative outcomes using our surgical procedure. The aim of this study was to evaluate the midterm and long-term postoperative outcomes in such cases.

METHODS

The study included 17 feet from 16 patients; 5 male and 11 female, with one bilateral case. The radiographic findings in all cases revealed a mosaic-like alignment of phalanges. Average age of the patients at the initial surgery was 12 months and average duration of post-operative follow-up was 89 months (60 to 132 mo). The surgical procedures were focused on the alignment between the distal and proximal phalanges independent of the middle phalanx alignment. Ligamentous joint stability was restored using collateral ligament reconstruction. We retrospectively evaluated post-operative outcomes, and subjective evaluation by the patients and parents was carried out.

RESULTS

No cases revealed either varus or valgus deformities, pigmentation of the grafted skin, or functional disturbance. As for postoperative complications, we observed visible thickening in 7 toes, 3 of which further underwent partial resection of the middle phalanx. Subjective evaluation of the postoperative results by the patients and parents was "very satisfied" or "satisfied" in 15 of 16 cases.

CONCLUSION

On the basis of our midterm to long-term postoperative outcomes, we believe that our method of surgical reconstruction provides a new option for the treatment of lateral polydactyly of the foot with mosaic-like alignment of the phalanx bones.

LEVEL OF EVIDENCE

Level IV-therapeutic studies.

Primary On-top Plasty for Treatment of Short-type Postaxial Polydactyly of the Foot

BACKGROUND

Postaxial polydactyly of the foot is typically treated with medial or lateral toe ray resection. However, simple ray resection does not always give a natural postoperative appearance, especially for short-type polydactyly. The purpose of this article was to describe our primary operation with on-top plasty for lengthening of short-type postaxial polydactyly.

METHODS

Four patients (mean age, 11.3 months) underwent this procedure. Ray transfer was performed at the proximal phalangeal level. Lateral distal and middle phalanges were resected and the medial ray was transferred on top of the remaining lateral proximal phalanx. Preoperative and postoperative toe lengths and complications were evaluated by comparison with the contralateral side on x-ray.

RESULTS

All toes were lengthened by a mean of 115.1% from the tip of the distal phalanx to the bottom of the proximal phalanx relative to contralateral side. Appearances were very natural without valgus deformity and hypertrophic scar. And there was no remaining dysfunction in walking after a mean of 21.5 months follow-up.

CONCLUSIONS

This on-top procedure is useful for improving toe lengthening and bone alignment correction with minimal functional disturbance.