Ankle Reconstruction in Fibular Hemimelia: New Approach

Abstract

Background: Fibular hemimelia is a congenital disorder that is characterized by the absence of the fibula that could be either partial or complete. Successful management aims to restore normal weight bearing and normal limb length. The introduction of the Ilizarov method of limb lengthening has provided an attractive alternative to amputation. During lengthening, the tight posterolateral soft-tissue structures, the thick fibrous fibular band, and the shortened Achilles tendon become tighter and transfer a valgus force to the talus and calcaneus, further aggravating the deformity.

Questions/purposes: We have developed a strategy to address this in patients with Paley type III fibular hemimelia via ankle reconstruction that provides posterolateral stability and buttressing of the ankle and hind foot by reconstructing the lateral buttress. This is achieved through excision of the fibrous fibular anlage, centralization of the ankle, restoring talocalcaneal coronal alignment, and reconstruction of the lateral malleolus by transplanting the cartilaginous remnant of the lateral malleolus or by crafting a bone block autograft taken from the iliac crest or tibia.

Methods: A prospective non-randomized clinical trial included ten ankles in eight patients with fibular hemimelia Paley type III (two patients had bilateral deformity). The patients' ages ranged from 7 to 36 months.

Results: After a follow-up ranging from 48 to 96 months, a stable plantigrade foot was achieved in nine ankles; one ankle had residual equinus, five ankles had residual valgus heel, and eight ankles had complete range of motion of the ankle, whereas one patient lost 5° of dorsiflexion. One ankle had equinus deformity.

Conclusions: To achieve satisfactory results, a stable plantigrade foot and ankle is necessary in patients with fibular hemimelia before attempting to equalize limb length discrepancy. It is important to reconstruct the ankle through an extra-articular soft tissue release, anlage resection, osteotomies, and restoring the abnormal talocalcaneal relationship before any attempt to equalize LLD.

Keywords: ankle reconstruction; fibular hemimelia.

Fig. 1

Preoperative AP weight-bearing hip-to-ankle radiographs of a 3-year-old female child with fibular hemimelia of the right leg, demonstrating complete absence of the fibula, genu valgum, hypoplastic lateral femoral condyle, and limb length discrepancy of 7 cm (5.5 cm tibial, 1.5 cm femoral).

Fig. 2

T1-weighted coronal magnetic resonance image through the ankle demonstrates talocalcaneal coalition (arrow) and lateral translation of the calcaneus in relation to the talus.

Fig. 3

Intraoperative image depicts exposure of the lateral side of the leg and exposure of the whole fibular anlage (forceps) and dissection of the superficial peroneal nerve free of it (arrow).

Fig. 4

Intraoperative image demonstrating excision of the fibrous fibular anlage and bulbous cartilaginous lateral malleolus.

Fig. 5

Intraoperative image depicting the lateral side of the right leg after complete excision of the fibular anlage and bulbous cartilaginous lateral malleolus; it also shows continuity of the superficial peroneal nerve at the proximal part of the wound.

Fig. 6

Intraoperative image demonstrating talocalcaneal coalition breakage by sharp osteotome passing from superolateral to inferomedial.

Fig. 7

Lateral view obtained intraoperatively with image intensifier depicting calcaneo-tibial transfixing K-wires, which were also advanced proximally intramedullary fixing the tibial corrective osteotomy.

Fig. 8

Schematic diagram explaining operative steps of ankle reconstruction. a Excision of the fibrous anlage and bulbous cartilaginous lateral malleolus (dotted lines). b Talocalcaneal breakage (red line) from a superolateral to inferomedial direction. c Talocalcaneal realignment and fixation by calcaneo-tibial wires; it also shows reimplantation of bulbous cartilaginous lateral malleolus at a more distal level (arrow).

Fig. 9

Image shows excised fibrous fibular anlage with bulbous cartilaginous later malleolus (arrow).

Fig. 10

Intraoperative image showing suturing (arrow) of the cartilaginous lateral malleolus onto the posterolateral aspect of the distal tibia after talocalcaneal realignment and fixation.

Fig. 11

Lateral radiographs of the leg in a cast taken immediate postoperatively, demonstrating realignment of the calcaneus beneath the talus and corrective of tibial osteotomy and securing positions with calcaneo-tibial intramedullary wires.

Fig. 12

Coronal T1-weighted magnetic resonance image through the ankle at 2-year follow up, demonstrating good talocalcaneal coronal alignment (arrow).

Fig. 13

Clinical photograph at 2 years follow up, depicts proper alignment of the right heel on weight bearing.

Fig. 14

Clinical photograph of the lateral side right leg, demonstrating neutral position of the ankle; it also shows the scar of a zigzag incision with no tethering effect of scar tissue.