Original Article DOI 10.3349/ymj.2011.52.4.655 pISSN: 0513-5796, eISSN: 1976-2437 Yonsei Med J 52(4):655-660, 2011 Total Hip Arthroplasty Using S-ROM Prosthesis for Dysplastic Hip Joon Soon Kang, Kyoung Ho Moon, Ryuh Sup Kim, Seung Rim Park, Jung Sun Lee, and Sang Hyun Shin Department of Orthopaedic Surgery, Inha University College of Medicine, Incheon, Korea. Received: July 7, 2010 Revised: December 17, 2010 Accepted: December 21, 2010 Corresponding author: Dr. Joon Soon Kang, Department of Orthopaedic Surgery, Inha University College of Medicine, 7-206 Sinheung-dong 3-ga, Jung-gu, Incheon 400-711, Korea. Tel: 82-32-89-2380, Fax: 82-32-890-2387 E-mail: kangjoon@inha.ac.kr ∙ The authors have no financial conflicts of interest. © Copyright: Yonsei University College of Medicine 2011 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/ licenses/by-nc/3.0) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose: The purpose of this study was to evaluate the clinical and radiological results of total hip arthroplasty using a proximal modular femoral stem in patients who had secondary coxarthrosis associated with a dysplastic hip. Materials and Methods: Forty-two patients (45 hips) with secondary coxarthrosis were evaluat- ed after undergoing primary total hip arthroplasty using an S-ROM proximal mod- ular femoral stem. The average follow-up was 80 months (range: 60 to 96 months). Clinical and radiological assessments were performed based on the Harris hip score and the radiological changes around the prosthesis. Results: The average Harris hip score improved from 52.2 points to 88.5 points. All femoral stems showed stable fixation; there were 37 cases by bony ingrowth and 8 cases by sta- ble fibrous ingrowth. Neither osteolysis nor progressive radiolucent lines around the femoral stem were found at the last follow-up. Forty-one hips (91.9%) revealed excellent or good clinical results at the most recent follow-up. Conclusion: For advanced secondary coxarthrosis, total hip arthroplasty with the use of the proxi- mal modular femoral stem yielded good mid-term results with respect to the clini- cal and radiological criteria. Key Words: Dysplastic hip, secondary coxarthrosis, total hip arthoplasty, S-ROM prosthesis INTRODUCTION The causative factors of secondary coxarthrosis include the sequelae of pediatric hip joint lesions such as the developmental dysplastic hip, Legg-Calve-Perthes (LCP) disease and a slipped capital femoral epiphysis, and also include inflamma- tory arthritis of the hip, infection, trauma and osteonecrosis of the femoral head.1 Hip joint diseases that develop in children lead to apoplasia. The surgery that is done for cases with mild deformation is virtually no different from the typical sur- gery that is done for standard primary total hip replacement. At the other extreme, the problems presented by severe forms of acetabular hypoplasia, femoral under- development and gross anatomic anomalies, including increased femoral antever- sion, a narrow femoral canal, leg length discrepancy and high riding great trochanter, Yonsei Med J http://www.eymj.org Volume 52 Number 4 July 2011 655