Monobloc implants in cementless total hip arthroplasty in patients with Legg-Calve-Perthes disease: a long-term follow-up

Luo et al. BMC Musculoskeletal Disorders (2017) 18:386 DOI 10.1186/s12891-017-1748-1 RESEARCH ARTICLE Open Access Monobloc implants in cementless total hip arthroplasty in patients with Legg-CalvePerthes disease: a long-term follow-up Ze-Yu Luo1, Hao-Yang Wang1, Duan Wang1, Hui Pan2, Fu-Xing Pei1 and Zong-Ke Zhou1* Abstract Background: The purpose of this study was to evaluate 10-year outcomes in cementless monobloc total hip arthroplasty (THA) in a group of hips with Legg-Calve-Perthes disease (LCPD). Methods: We reviewed 71 patients (88 hips) who underwent cementless THA with a diagnosis of LCPD from 2003 to 2009. From the total of 71 patients, 34 men and 37 women with an average age of 49.94 years were included. The mean follow-up period was 10 years. Results: The mean Harris Hip Score improved significantly from 46.42 to 89.70. Similarly, the postoperative range of motion, hip dysfunction and osteoarthritis outcome score and SF-12 score also significantly improved. The mean leg lengthening was 22.1 mm. During the follow-up, eight complications were noted, including two cases of intraoperative femoral fractures, two cases of sciatic nerve paralysis, two cases of heterotrophic ossifications, one case of thigh pain and one case of dislocation. One revision was conducted for a periprosthetic fracture, and the survivorship at 10 years was 98.3%. Conclusions: These data suggest that the monobloc stem can lead to satisfactory outcomes for clinical function, radiological evaluation, restoration of the normal limb lengths, complications, and survivorship among LCPD patients undergoing total hip arthroplasty. Keywords: Legg-calve-Perthes disease, Monobloc stem, Hip, Arthroplasty Background Legg-Calve-Perthes disease(LCPD) is characterized by osteonecrosis of the femoral head during childhood [1, 2]. Similar to other childhood hip disorders, LCPD has the development of degenerative coxarthrosis as its natural history [3]. Total hip arthroplasty (THA) is recommended for patients with end-stage hip disease [4]. Nevertheless, there are limited data available in the literature regarding the characteristics and complications of THA in patients with a history of LCPD [5–13]. THA for patients with LCPD is known to be technically demanding because of the flattens and widens of the femoral head, excessive anteversion of the femoral neck, a straight and narrow medullary canal of the femur, a * Correspondence: 1 Department of Orthopedics, West China Hospital/West China School of Medicine, Sichuan University, 37# Wuhou Guoxue Road, Chengdu 610041, People’s Republic of China Full list of author information is available at the end of the article shallow and retroverted acetabulum, and the abnormality caused by previous operations [5]. Coxa breva, a typical residual deformity of LCPD, consists of a short femoral neck, a large oval-shaped femoral head, a relatively overgrown greater trochanter, and a decreased femoral neckshaft angle [3]. The acetabulum is also deformed, becomes flat, and loses its concavity to accommodate the deformed femoral head. Frequently, the femoral head is subluxated laterally and incompletely covered by the acetabulum [3]. In 1984, the S-ROM system (DePuy, Warsaw, IN) was developed as a stem for patients with these various types of anatomic deformities. This stem has a modular mechanism with a high degree of freedom. It consists of two parts, the sleeve and stem body. In addition, the stem and sleeve have various combinations, and independent reaming in the proximal metaphyseal region of the femur and the diaphyseal region enables robust fixation with respect to various intramedullary canal shapes. Using the S-ROM © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Luo et al. BMC Musculoskeletal Disorders (2017) 18:386 prosthesis to treat LCPD has been reported to provide excellent results [8]. However, in with respect to modular femoral components, some risk factors need to be considered, such as fretting, corrosion, and mechanical failure, which may affect the stability of the stem and result in osteolysis and loosening. A recent series has documented the eight-year outcomes of 68 THAs with the use of a monobloc stem for LCPD [5]. However, monobloc cementless stems for patients with a history of Perthes’ disease raises several concerns: an increased risk of intraoperative femoral fracture, excessive anteversion of the femoral stem, malposition of the acetabular component, an increased risk of dislocation, unsatisfactory clinical and radiological results, and poor survivorship [5]. To address these concerns, we conducted this study to evaluate the 10-year outcomes of cementless monobloc THAs in a group of consecutive hips with LCPD. Methods This was a retrospective study conducted at West China Hospital, Sichuan University, which serves as a tertiary level center in China. The retrospective study protocol was approved by the Institutional Review Board of West China Hospital, and informed consent was obtained from all of the patients. Between June 2003 and December 2009, a total of 82 consecutive patients who underwent THA with a diagnosis of LCPD were included in our study. Eleven patients were excluded from the study for different reasons. Six patients were lost to follow-up after surgery and could not be contacted due to incorrect telephone numbers and addresses. Three patients with incomplete chart records were excluded. Two patients died of chronic medical problems which were unrelated to the THA. Therefore, 71 patients (88 hips) were included. The clinical data of our patients were evaluated retrospectively after receiving approval from the Institutional Review Board of West China Hospital. Clinical data There were 34 men and 37 women with an average age of 49.94 years (range, 25–73), and the average bodymass index (BMI) was 23.64 kg/m2 (range, 15.8–30.9). At our institution, patients undergoing arthroplasty are followed-up prospectively at regular intervals (at 3 weeks, 6 weeks, 12 weeks, and 6 months after surgery and annually thereafter). The time to follow-up is calculated as the time from surgery to the most recent visit. A clinical evaluation was conducted by two independent observers (ZY-L and HY-W) with the use of the Harris Hip Score (HHS), hip dysfunction and osteoarthritis outcome score (covering pain, symptoms, daily living, sports and recreational activities, and quality of life) and the (...truncated)