Yusuke Kohno1, Yasuharu Nakashima2, Toshio Kitano3, Taichi Irie4, Atsushi Kita5, Tomoyuki Nakamura6, Hirosuke Endo7, Yosuke Fujii7, Takayuki Kuroda8, Shigeru Mitani8, Hiroshi Kitoh9, Masaki Matsushita9, Tadashi Hattori10, Koji Iwata10, Yukihide Iwamoto1. 1. Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. 2. Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: yasunaka@ortho.med.kyushu-u.ac.jp. 3. Department of Pediatric Orthopaedic Surgery, Osaka City General Hospital, Osaka, Japan. 4. Department of Orthopaedic Surgery, Sendai City Hospital, Sendai, Japan. 5. Department of Orthopaedic Surgery, Japanese Red Cross Sendai Hospital, Sendai, Japan. 6. Department of Orthopaedic Surgery, Fukuoka Children's Hospital, Fukuoka, Japan. 7. Department of Orthopaedic Surgery, Okayama University, Okayama, Japan. 8. Department of Bone and Joint Surgery, Kawasaki Medical School, Kurashiki, Japan. 9. Department of Orthopaedic Surgery, Nagoya University, Nagoya, Japan. 10. Department of Orthopaedic Surgery, Aichi Children's Health and Medical Center, Obu, Japan.
Abstract
BACKGROUND: An unstable slipped capital femoral epiphysis (SCFE) is associated with a high rate of avascular necrosis (AVN). The etiology of AVN seems to be multifactorial, although it is not thoroughly known. The aims of our study were to determine the rate of AVN after an unstable SCFE and to investigate the risk factors for AVN, specifically evaluating the notion of an "unsafe window", during which medical interventions would increase the risk for AVN. METHODS: This retrospective multicenter study included 60 patients with an unstable SCFE diagnosed between 1985 and 2014. Timing of surgery was evaluated for three time periods, from acute onset of symptoms to surgery: period I, <24 h; period II, between 24 h and 7 days; and period III, >7 days. Multivariate logistic regression analysis was used to identify risk factors for AVN. RESULTS: Closed reduction and pinning was performed in 43 patients and in situ pinning in 17. Among these cases, 16 patients (27%) developed AVN. The rate of AVN was significantly higher in patients treated by closed reduction and pinning (15/43, 35%) than in those treated by in situ pinning (1/17, 5.9%) (p = 0.022). In patients treated by closed reduction and pinning, the incidence of AVN was 2/11 (18%) in period I, 10/13 (77%) in period II and 3/15 (20%) in period III, showing the significantly higher rate in period II (p = 0.002). The surgery provided in period II was identified as an independent risk factor for the development of AVN. CONCLUSIONS: Our rate of AVN was 27% using two classical treatment methods. Time-to-surgery, between 24 h and 7 days, was independently associated with AVN, supporting the possible existence of an "unsafe window" in patients with unstable SCFE treated by closed reduction and pinning.
BACKGROUND: An unstable slipped capital femoral epiphysis (SCFE) is associated with a high rate of avascular necrosis (AVN). The etiology of AVN seems to be multifactorial, although it is not thoroughly known. The aims of our study were to determine the rate of AVN after an unstable SCFE and to investigate the risk factors for AVN, specifically evaluating the notion of an "unsafe window", during which medical interventions would increase the risk for AVN. METHODS: This retrospective multicenter study included 60 patients with an unstable SCFE diagnosed between 1985 and 2014. Timing of surgery was evaluated for three time periods, from acute onset of symptoms to surgery: period I, <24 h; period II, between 24 h and 7 days; and period III, >7 days. Multivariate logistic regression analysis was used to identify risk factors for AVN. RESULTS: Closed reduction and pinning was performed in 43 patients and in situ pinning in 17. Among these cases, 16 patients (27%) developed AVN. The rate of AVN was significantly higher in patients treated by closed reduction and pinning (15/43, 35%) than in those treated by in situ pinning (1/17, 5.9%) (p = 0.022). In patients treated by closed reduction and pinning, the incidence of AVN was 2/11 (18%) in period I, 10/13 (77%) in period II and 3/15 (20%) in period III, showing the significantly higher rate in period II (p = 0.002). The surgery provided in period II was identified as an independent risk factor for the development of AVN. CONCLUSIONS: Our rate of AVN was 27% using two classical treatment methods. Time-to-surgery, between 24 h and 7 days, was independently associated with AVN, supporting the possible existence of an "unsafe window" in patients with unstable SCFE treated by closed reduction and pinning.
Authors: Daniel C Perry; Barbara Arch; Duncan Appelbe; Priya Francis; Joanna Craven; Fergal P Monsell; Paula Williamson; Marian Knight Journal: Bone Joint J Date: 2022-04 Impact factor: 5.385