Deformity Reconstruction Surgery for Tibial Hemimelia

Tibial hemimelia is a rare congenital deficiency with a wide spectrum of pathology and deformity. This paper aims to give a comprehensive review of tibial hemimelia, with a concise summary of the history, pathology, and clinical findings of tibial hemimelia, while providing treatment recommendations and a review of the current literature. Classifications and surgical treatments are discussed, including amputation, limb reconstruction, and lengthening. Type-specific treatments are also discussed, including staged distraction correction of joint contractures of knee and ankle, Weber patelloplasty, fibular centralization, knee and ankle arthrodesis, implantable articulated distractors, and the role of femoral shortening. Amputation is a simpler and easier solution for many patients; however, reconstruction options continue to evolve, improve, and provide better functional outcomes in many cases. Factors favoring surgical reconstruction include the presence of a knee joint/proximal tibia, and the presence of a patella and quadriceps mechanism.

Usual Presentation Has Odds: Unilateral Tibial Hemimelia in One of Dizygotic Twins

Tibial hemimelia is a relatively rare congenital tibial longitudinal deficiency (approximately 1 per 1 million live births), unilateral or bilateral, with a relatively intact fibula. Hemimelia results from a disruption of the lower limb developmental field during embryogenesis due to slow or even abort of chondrification process, which results in leg length discrepancy. Affected leg commonly appears short and deformed with knee, ankle, and foot involvement. It may present with a variety of associated anomalies. Surgical treatment varies according to the type and degree of deformity, and reconstructive interventions are still limited. Reported cases of tibial hemimelia are very infrequent, especially tibial hemimelia in twins. Usually, the cases were in single embryo or less frequently in one of the monozygotic twins, but no reported cases regarding tibial hemimelia in one of the dizygotic twins as this article reports.

Asymmetric limb lengthening in the treatment of tibial hemimelia caused by osteomyelitis: A case report

RATIONALE

Tibial hemimelia is known as a rare congenital lower limb deficiency. It has been classified into different types based on Jones classification, and the traditional treatment of tibial hemimelia is amputation. Here we present a variant and unclassified case of tibial hemimelia, which was caused by osteomyelitis. And the lower limb with tibial hemimelia was salvaged by asymmetric limb lengthening.

PATIENT CONCERNS

19-year-old girl had the shortened and curved left lower extremity with walking abnormalities.

DIAGNOSIS

The patient's deformity was caused by osteomyelitis of tibia occurred when she was 18 month old. The tibial shaft was absent, while the proximal and distal tibia was present but was hypoplastic with radiographic analysis. The fibula was hypertrophied and curved like the capital letter C. The leg length discrepancy (LLD), mostly coming from the left lower leg, was 22 cm.

INTERVENTIONS

We were able to salvage the limb successfully by 5 operations, including releasing soft tissue, fusing the proximal tibiofibular joint, fibular osteotomy, femur lengthening, and fibular lengthening.

OUTCOMES

The whole treatment time for the patient was 3 years and 2 months, and she was followed up for 5 years afterward. The length of femur lengthening and fibula lengthening during the reconstruction were 7.8 cm and 11 cm, respectively. Most of the deformities were corrected, except that the left lower limb was still 2 cm shorter than the contralateral limb, and the 34 mm of mechanical axis deviation (MAD) of left lower limb remained. The reason why the patient's lower limbs were asymmetric was that the femur and fibular lengthening were performed within the affected limb only. Overall, the patient was very satisfied with her asymmetric limbs and its function after surgeries.

LESSONS

The LLD in this case mainly came from tibial hemimelia. However, the fibula was unable to be lengthened to 22 cm during the lower leg distraction process because of blood flow disturbance. We could only lengthen the femur to salvage the limb in this situation. Even though the patient still had a few residual deformities and a pair of asymmetric lower limbs, she was satisfied with the function and appearance of the reconstructed limb. Therefore, the lower limb with tibial hemimelia can be salvaged by asymmetric limb lengthening in special cases.

A novel mutation (g.106737G>T) in zone of polarizing activity regulatory sequence (ZRS) causes variable limb phenotypes in Werner mesomelia

Werner mesomelia is characterized by a sequence variation in the specific region (position 404) of the enhancer ZRS of SHH. The phenotype comprises variable mesomelia, abnormalities of the thumb and great toe and supernumerary digits. We describe extensive variation in limb phenotype in a large family and report on a novel sequence variation NG_009240.1: g.106737G>T (traditional nomenclature: ZRS404G>T) in the ZRS within the LMBR1 gene. The newly recognized clinical features in this family include small thenar eminence, sandal gap, broad first metatarsals, mesoaxial polydactyly, and postaxial polydactyly. We provide information on 12 affected family members. We review the literature on how a sequence variation in ZRS may cause such diverse phenotypes.

Pre-axial mirror polydactyly associated with tibial deficiency: a study of the patterns of skeletal anomalies of the foot and leg

PURPOSE

The study was undertaken to identify the patterns and spectrum of aberrant development of the skeletal elements of the leg and foot in children with pre-axial mirror polydactyly of the foot.

METHODS

Case records and radiographs of eight children (ten feet) with pre-axial mirror polydactyly were studied. Four feet were seen in association with fibular dimelia, three feet with dysplastic trapezoid shaped tibia, two with tibial aplasia and one with tibial hypoplasia.

RESULTS

Distinct patterns of anomalies of the hindfoot, midfoot and forefoot were noted, with different patterns of leg malformation. Fibular dimelia was associated with duplication of the calcaneum, cuboid and the lateral cuneiform. Talar duplication occurred in children with a trapezoidal tibia. No duplication of tarsal bones was seen in association with tibial aplasia or hypoplasia. The first metatarsal was hypoplastic wherever the tibia failed to develop. Mere resection of the supernumerary rays resulted in a near normal looking foot in feet without calcaneal duplication. The cosmetic appearance of the foot was poorest in children with fibular dimelia.