Change in effective leg length after angular deformity correction by hemiepiphyseal stapling.
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 10 degrees , whereas to increase it if the amount of angular correction is larger than 16 degrees . This should be taken into consideration when selecting the surgical method for angular deformity correction in skeletally immature patients.
Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul, Korea.
Ho-Joong
HJ
Jung
Tae-Joon
TJ
Cho
In Ho
IH
Choi
Chin Youb
CY
Chung
Won Joon
WJ
Yoo
Moon Seok
MS
Park
Jung Yun
JY
Bae
D000293:Adolescent; D002648:Child; D004838:Epiphyses / Q000254:growth & development / Q000601:surgery*; D005260:Female; D056304:Genu Valgum / Q000601:surgery*; D056305:Genu Varum / Q000601:surgery*; D006801:Humans; D007870:Leg Length Inequality / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D017792:Surgical Stapling / Q000009:adverse effects