Published in:
01-11-2020 | Hip Dysplasia
Letter to the Editor on “Outcomes of computer-assisted peri-acetabular osteotomy compared with conventional osteotomy in hip dysplasia”
Published in: International Orthopaedics | Issue 11/2020
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We read with great interest the article titled “Outcomes of computer-assisted peri-acetabular osteotomy compared with conventional osteotomy in hip dysplasia” by Imai et al. and would like to congratulate the authors for their study [1]. Although they have touched a highly pertinent topic in a scientific manner, the study has brought several questions to our minds that we would like to communicate with the authors.
1.
A vertical axis-centre of the femoral head, anterior extremity of the acetabular roof (VCA) angle [2] is one of a reference of anterior coverage of the hip joint. In the study, the authors set the target zone of the VCA angle after eccentric rotational acetabular osteotomy (ERAO) for between 20 and 60°. However, the authors have previously reported that the VCA angle after ERAO ≥ 46° is a probable risk factor for pincer femoroacetabular impingement (FAI) [3]. Why didn’t the authors set target zone of the VCA angle to avoid FAI?
2.
The authors stated that the angle and direction of the osteotomy in conventional ERAO were determined by intra-operative X-ray. Certainly, the VCA angle was difficult to be evaluated by the false profiler view intra-operatively. However, the acetabular head index (AHI) was not difficult to be evaluated by intra-operative X-ray. Why did the results show that difference in the AHI between computer-assisted and conventional ERAO? Inaba et al. also compared computer-navigated and non-navigated RAO, and reported that no significant difference was observed in the AHI after surgery between computer-navigated and non-navigated groups [4].