If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Fibular hemimelia is a rare congenital disorder of unknown etiology characterized by fibular hypoplasia, dysplasia, or complete aplasia. The pathologic process is occasionally associated with other femoral, tibial and/or foot deformities. As these deformities can alter the mechanical axis of the lower extremity, abnormal joint mechanics predisposes those with fibular hemimelia to degenerative joint disease of the ankle joints, knee, and hip. Many reports have demonstrated surgical correction for complex tibial and fibular deformity in patients with fibular hemimelia; however, there is a general lack of documentation for surgical correction of ankle-driven deformity and pathology in patients with this congenital disorder. We present a case of Type 1A fibular hemimelia treated with total ankle replacement, with successful results recorded with over 12 years of follow-up.
Introduction
Fibular hemimelia is a devastating congenital deformity occurring in roughly 1/50,000 live births.
Although originally described as complete or partial absence of the fibula, further investigation of lower extremity hemimelia has identified deformities occurring in the tibia, foot, and occasionally the femur in conjunction with fibular deficiency. This deformity is frequently unilateral in presentation, with a higher prevalence in the right lower extremity and males relative to females.
Cardiac and renal anomalies have been rarely identified to have correlation with fibular hemimelia, and the pathological process most often occurs in isolation without supplemental systemic comorbidities. Despite extensive research, the exact cause for fibular deficiency remains unknown.
Similar to other deformities of the lower leg, fibular hemimelia can alter the mechanical axis of the lower extremity leading to abnormal joint mechanics and ultimately end stage osteoarthritis of the knee, hip, and ankle joints. While several case studies and reports have demonstrated complex and successful surgical correction of the fibula and tibia, there is lack of documentation supporting the use of ankle arthroplasty in deformity-driven ankle arthritis secondary to fibular deficiency.
With the increasing technology and biomechanical advancements in ankle joint arthroplasty in the last 20 years, modular stemmed implants have demonstrated exceptional longevity and success.
In this report we present a case of Type IA fibular hypoplasia treated with total ankle replacement arthroplasty and successful results recorded with over 12 years of follow-up after implantation.
Case report
A 60-year-old female with a history of congenital lower extremity deformity presented for surgical consultation following multiple years of failed conservative therapies for a chronically painfully arthritic ankle joint secondary to hypoplasia of the fibula. By this time, the discomfort and stiffness were functionally limiting, and the patient had failed nearly 10 years of conservative therapies. Clinical evaluation and diagnostic injection localized most of the pain to the ankle joint, with pronounced subfibular pain along the lateral ankle. Plain radiographs showed Achterman and Kalamchi Type 1A fibular hypoplasia, associated ball and socket talocrural joint and degenerative arthritic changes (Fig. 1a–c). These radiographs also exhibited moderate subtalar joint valgus with arthritic degeneration. Advanced imaging was obtained in the form of magnetic resonance imaging, which demonstrated significant loss of cartilage and associated deformity of the ankle joint. Lengthy and thorough discussions between surgeon and patient concluded that ankle arthroplasty was a more reasonable approach versus arthrodesis due to the comorbid hindfoot deformities. Expected outcomes were fully explained to the patient's understanding. The surgical plan consisted of right total ankle replacement with INBONE™ prosthesis (Wright Medical Technology, Arlington, TN), right percutaneous Achilles tendon lengthening and right subtalar joint arthrodesis.
Fig. 1a–c: Preoperative AP, Lateral, and Oblique Ankle Radiographs of Type 1A Fibular Hemimelia with Ball and Socket Ankle Joint.
The patient was brought into the operative theatre and placed on the table in the supine position. Attention was first directed to the lateral hindfoot where a subtalar joint incision was made. Once the articular surfaces of the subtalar joint were exposed, they were prepared for arthrodesis. Prior to fixation of the subtalar joint, we performed our anterior ankle joint dissection via a standard anterior ankle approach. Once this dissection was carried to a subperiosteal level, the ball and socket ankle joint was appreciated to be grossly deformed and arthritic throughout. Laterally, the ankle was unstable and full soft tissue releases were performed to realign the ankle joint. At this point, it was noted that the ankle was unable to reach dorsiflexion. A Hoke triple hemi section Tendo-Achilles lengthening was performed through three stab incisions; after which, an increase in ankle dorsiflexion was appreciated.
After full ankle alignment was obtained, the foot was loaded into the jig for the INBONE™ total ankle replacement implant. Proper alignment was then confirmed via multiple fluoroscopic views, and the standard surgical technique was then performed using a size 3 INBONE™ total ankle tibia implant and four segmental tibial stem components. The subtalar joint fusion was then completed utilizing the Wright Medical Endo-fuse® intraosseous fusion rods. Two of these triangular rods were placed across the subtalar joint, one anterior and one posterior along the tibial intertalar stump. The polyethylene component was inserted, and final fluoroscopic images were obtained, with excellent stability and placement of hardware re-confirmed.
A well-padded plaster splint was then applied with the foot held in rectus position, and the patient was instructed to be nonweightbearing in the immediate postoperative period.
Follow up
At most recent follow-up, the patient presented over 12 years status post ankle arthroplasty. The patient self-reported satisfaction with functionality of the right ankle, noting that she is able to golf, climb and perform all desired activities. She described occasional lateral-sided discomfort, but that never lingers. Physical examination showed appropriate sagittal plane range of motion. There was minimal side-to-side translation, but this was not manifested clinically nor via radiographs. Plain film radiographs showed a well-positioned, well-fixed modular stemmed ankle implant with fusion rods supporting the subtalar joint (Fig. 2a–c). There was no evidence of any wear or subsidence. Minimal talonavicular joint arthritis was noted. The patient is satisfied with her long-term surgical outcomes and will continue to follow-up every few years with updated radiographs.
Fig. 2a–c: Postoperative AP, Lateral, and Oblique Ankle Radiographs of Type 1A Fibular Hemimelia with Stable Implant Taken Over 12 Years Postoperatively.
Fibular hemimelia (FH) is a congenital deficiency characterized by fibular anomalies ranging from fibular hypoplasia to dysplasia and even complete aplasia. This deficiency can also be associated with a hypoplastic or dysplastic tibia and other developmental abnormalities of the foot and more proximal lower extremity structures.
Though rare, FH can have significant pathologic impact contributing to limb length discrepancy, foot and ankle deformities and deficiencies, tibial deformity, genu valgum and knee instability.
Foot and ankle deformities related to FH can be challenging and disabling. With the distal tibial physis commonly affected, the tibial articular surface is often concave in the frontal plane as part of a ball and socket joint. The talus ranges in shape, but often presents convex in the frontal plane. This deformity affects the functionality of the ankle joint and can be debilitating to the surrounding joints. Additionally, the deficient fibula is unable to provide adequate stabilization to the lateral ankle, allowing the ankle and/or subtalar joint to subluxate or roll into valgus.
Multiple reports have shown successful deformity-correcting surgical procedures for various pathologies associated with FH. The SUPERankle procedure, Systematic Utilitarian Procedure for Extremity Reconstruction, first described by Paley, has shown reproducible results with good clinical and radiographic outcomes for rigid and severe FH deformity.
Moreover, indications for total ankle arthroplasty continue to expand, with the ability to correct large deformity through implantation, or with ancillary procedures performed in conjunction with implantation.
Effects of patient-specific instrumentation and ancillary surgery performed in conjunction with total ankle implant arthroplasty: postoperative radiographic findings.
With improved technology and biomechanical advancements in total ankle joint arthroplasty, this procedure can be an efficous in the treatment of ankle-driven deformity and arthritis even in the setting of FH, with fibular, distal tibial and foot deformities.
We present a unique case with long-term follow-up of chronic ankle pain secondary to congenital unilateral lower extremity deformity with a ball and socket ankle joint, hypoplastic fibula, hindfoot valgus and equinus contracture. Total ankle arthroplasty with concomitant subtalar joint fusion and Tendo-Achilles lengthening was performed. At most recent follow-up, the patient is still doing well and able to functionally perform all desired activities, with no evidence of implant wear or subsidence. While further research is necessary to investigate its success in the given situation, total ankle arthroplasty proved to be a viable option for treatment of ankle-driven deformity in the presented case with complex ankle and fibula deformity.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Dr. Berlet is a consultant and on the design team for Wright Medical Technology and their total ankle replacement products.
Informed patient consent
Complete informed consent was obtained from the patient for the publication of this study and accompanying images.
Effects of patient-specific instrumentation and ancillary surgery performed in conjunction with total ankle implant arthroplasty: postoperative radiographic findings.
00091-X&id=gr1.jpg){kind=link}
00091-X&id=gr2.jpg){kind=link}