- among most frequent limb anomalies is partial or total absence of fibula;
- it is most common long bone deficiency and is the most common skeletal deformity in the leg;
- most often is unilateral;
- paraxial fibular hemimelia is the most common manifestation (only the postaxial portion of the limb is affected)
- commonly seen as complete terminal deficiency (lateral rays of the foot are affected as well);
- hemimelia can also be intercalary in which case the foot remain unaffected;
- it is prudent to remember that although congenital absence of fibula is evident, this condition is actually a total limb involvement;
- males are affected twice as often as females in most series;
- Clinical Presentation:
- involved limb is usually shortened, and the foot is in equinovalgus position;
- classically the skin has dimpling seen over the tibia;
- clinically, primary problems related to fibular hemimelia are limb length inequality and foot/ankle instability;
- Associated Anomalies:
- coxa vara
- proximal femoral focal deficiency
- associated femoral shortening adds to limb length discrepancy;
- at skeletal maturity, this averages about 5 in / 12 cm;
- ankle instability;
- equinovarus/valgus foot (+/- absent lateral rays)
- lateral column deficiency of the foot;
- ref: Fibular hypoplasia with absent lateral rays of the foot.
- tarsal coalition;
- ref: Talocalcaneal coalition in patients who have fibular hemimelia or proximal femoral focal deficiency. A comparison of the radiographic and pathological findings.
- anterior tibial bowing (vs. anterolateral bowing)
- abnormality of the distal tibial physis;
- deficiency in muscles on the peroneal side of the leg;
- treatment varies from a simple shoe lift, or bracing, or Syme amputation;
- Limb Lengthening:
- indicated only for less severe cases w/ a relatively normal foot and ankle;
- ref: Management of congential fibular deficiency by Ilizarov technique.
- Syme Amputation:
- preferred method of treatment is early ablation of foot by ankle disarticulation of Syme type, producing a sturdy end-bearing stump;
- amputation is usually done at about 10 months to two years of age;
- w/ extreme limb length inequality, or when gross instability at foot/ ankle is present, Syme amputation allows application of a
highly functional below-knee prosthesis;
- conversion to a long amputation stump addresses the leg length problem and avoids multiple procedures necessary to
maintain plantigrade foot and limb of equal length;
- in the study by McCarthy JJ, et al, the authors compared functional results between amputation vs tibial lengthening;
- authors specifically compared activity restrictions, pain, satisfaction, complications, number of procedures, and cost, in
children with fibular hemimelia;
- 30 limbs in 25 patients treated with either an amputation or a lengthening procedure and followed for at least two years - 15 patients underwent amputation, and ten patients underwent lengthening of the tibia;
- mean age was 1.2 years at the time of amputation and 9.7 years at the time of initial lengthening;
- patients who underwent amputation were able to perform more activities than those who had a lengthening (mean
activity score, 0 compared with 1.2 points; p < 0.05), and they had less pain (mean pain score, 0.2 compared with
1.2 points; p = 0.091), were more satisfied and had a lower complication rate (0.37 compared with 1.91; p < 0.05).
- patients who underwent amputation also had fewer procedures (1.9 compared with 7.0; p < 0.05), at a lower cost ($7016
compared with $26,900; p < 0.05), than those who had a lengthening.
- lengthening was successful in equalizing limb lengths; the mean limb-length discrepancy, assessed in nine of eleven
limbs, was 0.7 centimeter;
- ref: Congenital longitudinal deficiency of the fibula: follow-up of treatment by Syme amputation.
Congenital absence of the fibula. Treatment by Syme amputation: Indications and technique.
Syme amputation: An evaluation of the physical and psychological function in young patients.
Amputation and prosthesis as definitive treatment in congenital absence of the fibula.
Congenital longitudinal deficiency of the fibula (fibular hemimelia). Parental refusal of amputation.
Fibular hemimelia: comparison of outcome measurments after amputation and lengthening.
Vascular dysgenesis associated with skeletal dysplasia of the lower limb.