BACKGROUND: The hemiepiphyseal stapling has both positive and negative effects on effective leg length. The purpose of this study was to analyze change in effective leg length after angular correction by hemiepiphyseal stapling, and to validate in clinical cases. METHODS: Mathematical analysis of a hemiepiphyseal stapling model was conducted. The induced formula was validated in 6 cases fulfilling the assumptions of the model. Anatomical parameters involved in this formula were measured in additional 21 cases undergoing hemiepiphyseal stapling or hemiepiphysiodesis. RESULTS: Effective leg length increased or decreased according to three parameters in this model: 1) limb length distal to the operated physis (L), 2) width of the operated physis (d), and 3) the amount of angular deformity to be corrected (theta). Actual change in effective leg length of 6 cases similar to this model coincided with the predicted change at least in its direction. L/d ratio was 4.82 +/- 0.51. CONCLUSIONS: Considering the narrow range of the L/d ratio, hemiepiphyseal stapling is likely to decrease effective leg length if the amount of angular correction is less than 10degrees, whereas to increase it if the amount of angular correction is larger than 16degrees. This should be taken into consideration when selecting the surgical method for angular deformity correction in skeletally immature patients.
Adolescent ; Child ; Epiphyses/growth & development/*surgery ; Female ; Genu Valgum/*surgery ; Genu Varum/*surgery ; Humans ; Leg Length Inequality/diagnosis/*etiology ; Male ; *Surgical Stapling/adverse effects

OBJECTIVE: To explore the efficacy and experience of callus distraction technique with the external fixator for valgus deformity of the knee companied with leg shortening in young patients and to provide evidence for selecting reasonable therapy. METHODS: From January 2002 to January 2009, the clinical data of 28 young patients (17 males and 11 females, aged 8 to 14, mean age 11.9 years) treated with callus distraction, who had valgus deformity of the knee, companied with leg shortening, were analyzed retrospectively. Three had bilateral total valgus deformity of the knee, with a total of 31 knees. Before the operation, the abnormal limbs shortened from 3 to 7 cm (average 4.1 cm) companied with the normal one. The tibiofemoral angle ranged from 138° to 160° (mean angle 148°) and the Condyle interval from 5 to 33 cm (mean interval 15.2 cm). RESULTS: The 28 patients were followed up for 35 to 84 ( mean 62 ) months. The extent length ranged from 4.5 to 10.1 cm (average 6.8 cm). The tibiofemoral angle ranged from 169° to 175° (mean 173°) after the union. The patients resumed the normal length of limbs, and the severe valgus deformity of the knee was corrected. CONCLUSION Callus distraction with external fixator is effective for serious valgus deformity of the knee companied with leg shortening.
Adolescent ; Child ; External Fixators ; Female ; Genu Valgum ; complications ; surgery ; Humans ; Ilizarov Technique ; Leg Length Inequality ; complications ; surgery ; Male ; Osteogenesis, Distraction ; methods