Limb Lengthening in Patients with Achondroplasia.

PURPOSE: Although bilateral lower-limb lengthening has been performed on patients with achondroplasia, the outcomes for the tibia and femur in terms of radiographic parameters, clinical results, and complications have not been compared with each other. We proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related to lengthening. MATERIALS AND METHODS: We retrospectively reviewed 28 patients (average age, 14 years 4 months) with achondroplasia who underwent bilateral limb lengthening between 2004 and 2012. All patients first underwent bilateral tibial lengthening, and at 9-48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. We analyzed the pixel value ratio (PVR) and characteristics of the callus of the lengthened area on serial radiographs. The external fixation index (EFI) and healing index (HI) were computed to compare tibial and femoral lengthening. The complications related to lengthening were assessed. RESULTS: The average gain in length was 8.4 cm for the femur and 9.8 cm for the tibia. The PVR, EFI, and HI of the tibia were significantly better than those of the femur. Fewer complications were found during the lengthening of the tibia than during the lengthening of the femur. CONCLUSION: Tibial lengthening had a significantly lower complication rate and a higher callus formation rate than femoral lengthening. Our findings suggest that bilateral limb lengthening (tibia, followed by femur) remains a reasonable option; however, we should be more cautious when performing femoral lengthening in selected patients.

Extent of physeal involvement in Legg-Calvé-Perthes disease.

PURPOSE: The growth plate involvement (GPI) index is reportedly a reliable predictor of final radiographic outcome in Legg-Calvé-Perthes disease (LCPD). We determined whether (1) the GPI index was associated with the lateral pillar classification, (2) the GPI index could predict the final radiographic outcome, and (3) the geometry of proximal femur was affected by presence of physeal involvement. METHODS: We reviewed 47 patients with unilateral LCPD who were treated conservatively. The mean duration of follow-up was 9.5 years (range, five to 13 years). The affected hips were categorized into those with and without physeal involvement. Herring classifications were determined and the GPI indices were estimated at the stage of maximum fragmentation. The Stulberg classification, leg length discrepancy (LLD), articulotrochanteric distance (ATD) index, neck-shaft angle (NSA), neck width and height were determined at skeletal maturity. RESULTS: The GPI indices were lower in Herring groups A and B (p < 0.001) and Stulberg classes I and II (p = 0.002), and these values were increased in the Herring group B/C and C and Stulberg classes III, IV and V. However, the age of onset, LLD and ATD index at skeletal maturity were not associated with the GPI index. The NSA of the affected hips with physeal involvement was significantly different compared to that of unaffected hips (p < 0.001). CONCLUSIONS: The GPI index could be used to determine the extent of physeal involvement in LCPD, and might be considered one of the prognostic values of radiographic development in patients with LCPD who are treated conservatively.