Complications of Ilizarov leg lengthening: a comparative study between patients with leg length discrepancy and short stature.

The Ilizarov technique has been used to treat severe limb length discrepancy and short stature. However, complications of this treatment are frequent. Between 1984 and 2001, 57 patients (94 tibias) had an Ilizarov procedure for limb lengthening. Twenty patients had limb discrepancy and 37 had short stature. Their mean age was 20.2 years (range 15-34). The average limb lengthening was 8.37 cm (range 3.2-14.7), which was equivalent to 26% (range 9.2-60%) average tibial lengthening. A total of 90 complications were observed. Thirty-three unplanned procedures were required during the lengthening programme. Two patients stopped the lengthening programme. There was no difference in the complications in leg lengthening using Ilizarov technique between the group of patients with leg length discrepancy and the group with short stature. A good knowledge of the Ilizarov technique is necessary to perform a lengthening programme with a low rate of complications.

Contribution of the advanced glycation end product pentosidine and of maturation of type I collagen to compressive biomechanical properties of human lumbar vertebrae.

Collagen characteristics contribute to bone biomechanical properties. Yet, few studies have analyzed the independent contributions of bone mineral density (BMD) and post-translational modifications of type I collagen to whole bone strength. Thus, the aim of this study was to determine the relative contributions of BMD and both enzymatic and non-enzymatic collagen crosslink concentration to the biomechanical properties of human vertebrae. Nineteen L3 vertebrae were collected after necropsy (age 26-93; 10 males, 9 females). BMD of the vertebral body was measured by DXA, and the vertebrae were compressed to failure to assess the stiffness, failure load and work to fracture. After mechanical testing, the concentration of both enzymatic crosslinks pyridinoline (PYD), and deoxypyridinoline (DPD) as well as, and the non-enzymatic crosslinks pentosidine (PEN) were analyzed in trabecular and cortical bone by reversed-phase HPLC. The extent of aspartic acid isomerization of type I collagen C telopeptide (CTX) was evaluated by ELISA of native (alpha CTX) and isomerized (beta CTX) forms. BMD was significantly positively related with stiffness (R(2) = 0.74; P < 0.0001), failure load (R(2) = 0.69; P < 0.0001) and work to fracture (R(2) = 0.44; P = 0.002). Bivariate regression analysis showed no association between collagen traits and biomechanical properties. However, in a multiple regression model, BMD and trabecular PEN were both significantly associated with failure load and work to fracture (multiple R(2) = 0.83, P = 0.001 and R(2) = 0.67, P = 0.001, respectively). Similarly, BMD and trabecular alpha/beta CTX ratio were both associated with stiffness (multiple R(2) = 0.83, P = 0.015). These findings indicate that post-translational modifications of type I collagen have an impact on skeletal fragility.