Fibular Graft: An Alternative Option in Calcaneal Lateral Column Lengthening

Abstract

Background

Evan opening wedge osteotomy is a gold-standard option for lateral column lengthening in skeletally immature patients. Various types of grafts are used to support lengthening, including autografts, allografts, xenografts and specialised plate systems. Each of them has its advantages and disadvantages. Iliac crest autograft is the most commonly utilised graft with excellent results. However, it has complications related to donor site morbidity and persistent iliac pain. The study aims to display the clinical and radiological outcomes of mid-fibular autograft used for Evans calcaneal lengthening osteotomy in skeletally immature patients with symptomatic flexible pes planovalgus.

Patients and methods

This prospective single-centre case series included 29 teenagers who had symptomatic pes planovalgus and were included in the study from January 2018 to July 2024, with an average age of 10.9 years. Thirteen patients (44.8%) were operated on the right side and sixteen patients (55.2%) on the left side. Worth's classification was used to evaluate the incorporation of the graft from the 6th to 8th week.

Results

The graft size taken in the study was 11.9 mm. Full union of the graft was noticed in all patients within 7.2 weeks. Significant improvement was noticed in calcaneal inclination and lateral talus-first metatarsal angle. Significant improvements in the AOFAS ankle-foot scale from 67 preoperatively to 98.2 postoperatively. The graft incorporation was in the third degree in seven patients (24.1%) and the fourth degree in 22 patients (75.9%). Regeneration of the donor site occurred in all cases within 10 months.

Conclusion

Fibular autograft demonstrated satisfactory clinical and radiographic outcomes with successful graft incorporation in this cohort. These findings suggest that fibular autograft is a feasible option for Evans calcaneal lengthening osteotomy.

Introduction

Pes planovalgus is a complex three-dimensional deformity that involves loss of the longitudinal arch height of the foot with a frequent association of hindfoot valgus and forefoot abduction.¹ This deformity is commonly seen in childhood as a mobile, asymptomatic, self-limiting flat foot but can progressively worsen, causing pain and affecting daily activities.^2,3

Both surgical and nonsurgical treatments aim to relieve patients' symptoms by correcting the elements of foot deformity. In childhood and adolescence, any management options must respect the growing physis and joints.^2–4

Lateral column lengthening, as described by Evans, is still the most attractive choice in skeletally immature patients, as it corrects the deformity, permitting further growth of the physis without affecting joint development. This procedure involves embedding a structural bone graft into an open wedge osteotomy at the anterior process of the calcaneus. For this procedure, tricortical iliac crest autografts, as initially reported by Mosca, are the most widely used due to their rapid incorporation, favourable osteoinductive and osteoconductive properties, and adequate biomechanical resistance. However, potential complications such as donor site morbidity and persistent iliac pain remain concerns.^4–8

Cadaveric allograft, xenograft, and artificial implant may be used to achieve the same goal of lateral column lengthening, with each method having specific advantages and disadvantages depending on clinical needs.⁹

This study aimed to evaluate the feasibility, graft incorporation, and clinical and radiographic outcomes of fibular autograft in Evans calcaneal lengthening osteotomy. Given the limited literature describing fibular autograft use for this indication in skeletally immature patients, this study seeks to contribute additional outcome data regarding this technique.

Patients and Methods

This was a prospective single-centre case series performed on 29 teenagers (20 boys and nine girls) with flexible pes planovalgus from Jan 2018 to July 2024. Ethical approval was obtained from the Hospitals and Educational Institutes Authority Review Board. Inclusion criteria were symptomatic flexible pes planovalgus deformity after conservative treatment failure in skeletally immature patients. Rigid pes planovalgus, cerebral palsy and skeletally mature patients were excluded from the study. The mean follow-up was 21.4 months, ranging from 16 to 36 months. The patients' average age during surgery was 10.9 years, with a range of 7–16 years. Thirteen patients, accounting for 44.8%, underwent surgery on the right side, while 16 patients, representing 55.2%, had surgery on the left side.

Preoperatively, anteroposterior (AP) and lateral weight-bearing radiographs were acquired for both feet and ankles. Radiological assessment included lateral talus-first metatarsal angles, anteroposterior talus-first metatarsal angle and calcaneal inclination angle. Normal values of these angles are in this manner: the calcaneal inclination angle ranges from 15° to 30°, the AP talus first metatarsal angle ranges from 10° to 20° and the lateral talus first metatarsal angle ranges from 7° to 20°.

Surgical planning considered the equinus deformity and Achilles tendon tightness. Therefore, percutaneous lengthening was performed before the calcaneal osteotomy if indicated.

Operative Technique

For Evan's calcaneal lengthening osteotomy, an incision was made across the anterior process paralleling the peroneal tendons. A transverse osteotomy was performed 1.2 cm from the calcaneocuboid joint. A lamina spreader was utilised to open the osteotomy (Fig. 1).

Figs 1A and B.

(A) Osteotomy site 1.2 cm from the calcaneocuboid joint; (B) Lamina spreader to open the osteotomy

For the graft, a 4-cm skin incision was used over the middle part of the lateral ipsilateral leg. The mid-third fibula was exposed by splitting the deep fascia across the posterior inter-muscular septum to avert injury to the superficial peroneal nerve. After periosteal dissection, the fibula was exposed, and a mid-third fibular bone graft was harvested using a saw. The graft was trapezoidal in shape and had a length compatible with the osteotomy requirement (Fig. 2).

Fig. 2.

Lateral mid-leg incision with splitting of the deep fascia exposing the mid-fibula along the posterior inter-muscular septum

The graft was compressed into the osteotomy site with its long border facing outward. Supplemental K-wire fixation for stability was inserted from distal to proximal into the body of the calcaneus (Fig. 3).

Fig. 3.

Fibular bone graft impacted into the osteotomy site with K-wire fixation used for stability

Postoperatively, the foot was immobilised in a short leg cast for 6 weeks. After 6 weeks, the K-wire was detached, whereas full weight bearing was permitted in the cast for an additional 2 weeks. No anticoagulant was prescribed. From the 6th to 8th week, Worth's classification was used to evaluate the incorporation of the graft and the AOFAS score was employed to assess the clinical outcomes (Table 1).¹⁰

Table 1.

Worth's classification system for radiographic evaluation of bone graft incorporation

Grade	Description
G1	Lucent graft site indicating graft failure
G2	Obvious lytic line at the interface of the graft to the surrounding host bone or a partially lytic graft site
G3	No lytic line is present, but an obvious graft/host interface is still to be remodelled
G4	Difficulty in discerning the graft site because of successful remodelling of graft trabeculae into those of the host bone

Results

The average graft size taken in the study was 11.9 mm, with a range from 8 to 15 mm. Full graft union was observed in 100% of patients within 7.2 weeks, ranging from 5 to 10 weeks. Cast immobilisation lasted for an average of 9.2 weeks, ranging from 7 to 12 weeks. Graft incorporation was classified as third degree in seven patients, accounting for 24.1% and fourth degree in 22 patients, representing 75.9% (Fig. 4). Donor site regeneration occurred in all cases within 10 months (Fig. 5).

Fig. 4.

Adequate incorporation of fibular graft in the osteotomy site 10 weeks postoperatively

Fig. 5.

Regeneration of the donor site occurred 10 months postoperatively

Significant improvements were observed in the calcaneal inclination, the lateral talus-first metatarsal angle and the AP talus-first metatarsal angles at 8 months postoperatively. The calcaneal inclination angle improved from a mean of 5.9° preoperatively to an average of 18.9° postoperatively. The lateral talus-first metatarsal angle ameliorated from an average 19.8° preoperatively to an average 6.5° postoperatively. The anteroposterior talus-first metatarsal angle ameliorated from an average 14.7° preoperatively to an average 5.1° postoperatively (Fig. 6).

Figs 6A and B.

Lateral foot view showing postoperative correction. (A) Calcaneal inclination angle increased to 14°; (B) Lateral talus-first metatarsal angle improved to 2°

The AOFAS ankle-foot scale for the clinical outcomes showed a significant improvement, with the score increasing from 67 preoperatively to 98.2 postoperatively.

No donor-site complications, wound problems, neurovascular injuries, or graft failures were identified during the follow-up period.

Discussion

Lateral column lengthening for pes planovalgus deformity in skeletally immature patients yields good clinical and radiological findings, with great patient satisfaction and appropriate complication rates.²

Graft selection embraces autologous iliac bone grafts, allografts, xenografts and artificial grafts.

Autografts can be harvested from many sites. Tricortical iliac crest autografts are commonly used due to their high union rates. Anterior iliac autograft harvest can cause complications such as iliac wing fractures, postoperative hematomas, sensory disturbances and hernia. The posterior iliac autograft is linked to extra postoperative pain over the anterior approach, which may be more than that from the procedure itself.^11–14

Local calcaneal grafts reduce postoperative pain by limiting incisions to one surgical site, but they may result in longer scars, increased swelling and wound complications.¹⁵

Comparisons between autografts and allografts show no significant differences in union rates or loss of correction. However, allografts pose risks of immunogenicity and disease transmission.¹⁶ Storage requirements and limited availability may also restrict their use.^17,18

The use of xenogeneic bone grafts in foot surgeries has been widely debated. Although the physical characteristics of xenogeneic grafts suggest favourable surgical outcomes, numerous studies have shown that the incorporation rates of these grafts in reconstructive foot surgery take longer than expected.^9,19,20

Artificial support techniques, such as interposition plating, have shown high success rates, with a 92.3% union rate in Foster et al.'s¹¹ 2017 study and a 96.5% success rate in Gross et al.'s study.²¹ However, drawbacks include higher costs, hardware pain, scar neuritis, and potential second surgeries for hardware removal after union.^22–24

In the present study, union was achieved in all patients. Previous reports of iliac crest autografts and allografts have demonstrated union rates ranging from 92 to 100%. The findings of the current study, therefore, fall within the range of outcomes reported in the literature.

Fibular graft sites regenerated well due to mid-third fibular harvesting with preserved periosteum. This is consistent with Güven et al.'s²⁵ study on partial fibular grafts in subtalar arthrodesis for cerebral palsy patients.

In the present series, fibular autograft demonstrated complete graft union and satisfactory radiographic correction. The observed outcomes were comparable to union rates reported for iliac crest autografts, allografts and implant-supported techniques in previous studies. However, the absence of a comparison group prevents definitive conclusions regarding superiority or comparative effectiveness.

The rationale for using fibular autograft in our institution was to provide a structural autologous graft while avoiding some of the concerns associated with iliac crest harvesting. Nevertheless, the current study was not designed to compare donor-site morbidity between graft types.

Limitations

This study has several limitations. First, it was a single-centre case series without a comparator group, limiting the ability to determine whether fibular autograft offers advantages over other graft options. Second, the sample size was relatively small, which may limit the detection of uncommon complications. Finally, although follow-up was sufficient to assess graft incorporation and early outcomes, longer-term follow-up is necessary to evaluate durability of correction, donor-site remodelling and late complications.

Conclusion

Fibular autograft demonstrated successful incorporation and satisfactory clinical and radiographic outcomes in this single-centre case series of skeletally immature patients undergoing Evans calcaneal lengthening osteotomy. These findings support the feasibility of this technique. However, given the absence of a comparator group, no conclusions regarding superiority over other graft options can be made.

Clinical Significance

• Fibular autograft showed successful graft incorporation with satisfactory clinical and radiographic outcomes following Evans calcaneal lengthening osteotomy in skeletally immature patients.

• The findings support the feasibility of using fibular autograft for this procedure.

• Due to the lack of a comparator group, superiority over alternative graft options cannot be determined.

Ethical Approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of the General Organisation of Teaching Hospitals and Institutes, Cairo, Egypt. Approval Number is HB000118.

Artificial Intelligence (AI) Disclosure

The authors used an AI-assisted language tool (ChatGPT, OpenAI) solely to improve grammar, spelling, and language clarity during manuscript preparation. All scientific content, study design, data analysis, interpretation of results, and final manuscript approval were performed by the authors. The authors take full responsibility for the accuracy and integrity of the manuscript.

Acknowledgements

The authors would like to express their gratitude to the Orthopedic resident teams in our institutes for their cooperation throughout the completion of the project.

Authors' Contributions

Mohamed AE Hussein: Conceived the study, performed all surgical procedures and clinical assessments, wrote the initial draft, corrected and revised the manuscript. Fahad Hayyawi: Writing initial draft, review of literature, correction and revision of manuscript, data collection. Mohamed El-Hariry: Review of literature, correction and revision of manuscript, data collection. Hussein A Hussein: Review of literature, correction and revision of manuscript, data collection. Mostafa I Awad: Assisted in all surgical procedures and clinical assessment, writing the initial draft, review of literature, correction and revision of the manuscript and data collection.

Orcid

Fahad A Hayyawi https://orcid.org/0000-0003-1149-6913

Data Availability

The datasets analysed during the current study are available from the corresponding author upon reasonable request.