Skyrmion Collapse Rate Computation via Forward Flux Sampling and Comparison with Langer’s Theory

Objectives Using a simple classification method, we aimed to estimate the collapse rate due to osteonecrosis of the femoral head (ONFH) in order to develop treatment guidelines for joint-preserving surgeries. Methods We retrospectively analyzed 505 hips from 310 patients (141 men, 169 women; mean age 45.5 years (sd 14.9; 15 to 86)) diagnosed with ONFH and classified them using the Japanese Investigation Committee (JIC) classification. The JIC system includes four visualized types based on the location and size of osteonecrotic lesions on weightbearing surfaces (types A, B, C1, and C2) and the stage of ONFH. The collapse rate due to ONFH was calculated using Kaplan–Meier survival analysis, with radiological collapse/arthroplasty as endpoints. Results Bilateral cases accounted for 390 hips, while unilateral cases accounted for 115. According to the JIC types, 21 hips were type A, 34 were type B, 173 were type C1, and 277 were type C2. At initial diagnosis, 238/505 hips (47.0%) had already collapsed. Further, the cumulative survival rate was analyzed in 212 precollapsed hips, and the two-year and five-year collapse rates were found to be 0% and 0%, 7.9% and 7.9%, 23.2% and 36.6%, and 57.8% and 84.8% for types A, B, C1, and C2, respectively. Conclusion Type A ONFH needs no further treatment, but precollapse type C2 ONFH warrants immediate treatment with joint-preserving surgery. Considering the high collapse rate, our study results justify the importance of early diagnosis and intervention in asymptomatic patients with type C2 ONFH. Cite this article: Y. Kuroda, T. Tanaka, T. Miyagawa, T. Kawai, K. Goto, S. Tanaka, S. Matsuda, H. Akiyama. Classification of osteonecrosis of the femoral head: Who should have surgery?. Bone Joint Res 2019;8:451–458. DOI: 10.1302/2046-3758.810.BJR-2019-0022.R1.

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Anterolateral Necrotic Lesion Serves as an Early Warning Sign of Developing Collapse in Osteonecrosis of the Femoral Head

10.21203/rs.3.rs-676727/v1 ◽

2021 ◽

Author(s):

Qiu-Shi Wei ◽

Min-Cong He ◽

Xiao-Ming He ◽

Tian-Ye Lin ◽

Peng Yang ◽

...

Keyword(s):

Femoral Head ◽

Bone Structure ◽

Weight Bearing ◽

Type A ◽

Necrotic Lesion ◽

Initial Time ◽

Type B ◽

Joint Preserving Surgery ◽

Collapse Rate

Abstract Objective: Load bearing capacity of the bone structure of anterolateral weight-bearing area plays an important role in the progressive collapse in osteonecrosis of the femoral head (ONFH). The purpose of this study is to assess the efficacy of combined evaluation of anteroposterior (AP) and frog-leg lateral (FLL) view to diagnose collapse.Methods: Between December 2016 to August 2018, a total of 478 hips from 372 patients with ONFH (268 men, 104 women; mean age 37.9±11.4 years) were retrospectively evaluated. All patients received standard AP and FLL views of hip joints. Japanese Investigation Committee (JIC) classification system was used to classified necrotic lesion in AP view. Anterior necrotic lesion was evaluated by FLL view. All patients with precollapse ONFH underwent non-operative hip preserving therapy. The collapse rate was calculated and compared with Kaplan–Meier survival analysis with radiological collapse as endpoints.Results: Forty-four (44/478, 9.2%) hips were classified as type A, 65 (65/478, 13.6%) as type B, 232 (232/478, 48.5%) as type C1, and 137 (137/478, 28.7%) as type C2. Three hundred cases (300/478, 62.5%) were collapsed at the initial time point. Two hundred and twenty six (226/300, 75.3%) hips and 298 (298/300, 99.3%) hips collapse were identified with AP view and FLL view, respectively. An average follow-up of 37.0±32.0 months was conducted to evaluate the occurence of collapse in 178 precollapse hips. During follow-up period, collapse occurred in 89 hips (50.0%). Seventy-seven (77/89, 86.5%) hips was determined with AP view alone and 85 (85/89, 95.5%) hips were determined with combination of AP and FLL views. The collapse rate at five years were reported as 0% and 0%, 16.2% and 24.3%, 58.3% and 68.1%, and 100% and 100% according to combination of AP and FLL views or AP view alone for types A, B, C1, and C2, respectively.Conclusion: The collapse can be diagnosed more accurately by combination of AP and FLL views. Besides, JIC type A and type B ONFH can be treated with conservative hip preservation, but precollapse type C2 ONFH should be treated with joint-preserving surgery. Type C1 needs further study to determine which subtype has potential risk of collapse.

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Family-size variability grows with collapse rate in a birth-death-catastrophe model

Physical Review E ◽

10.1103/physreve.98.012416 ◽

2018 ◽

Vol 98 (1) ◽

Author(s):

N. Dori ◽

H. Behar ◽

H. Brot ◽

Y. Louzoun

Keyword(s):

Family Size ◽

Catastrophe Model ◽

Size Variability ◽

Collapse Rate ◽

Birth Death

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Foam Collapse Rate

ASBC Methods of Analysis ◽

10.1094/asbcmoa-beer-22 ◽

2011 ◽

Author(s):

ASBC Technical Committe

Keyword(s):

Collapse Rate

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A historical supernova's lower limit to the galactic stellar collapse rate

Astrophysics and Space Science ◽

10.1007/bf00642970 ◽

1991 ◽

Vol 184 (2) ◽

pp. 221-225

Author(s):

Lizhi Fang ◽

Jiasheng Huang ◽

Jean-Marc Bonnet-Bidaud

Keyword(s):

Lower Limit ◽

Stellar Collapse ◽

Collapse Rate

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300 mm Wafer Development for Pattern Collapse Evaluations

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.282.207 ◽

2018 ◽

Vol 282 ◽

pp. 207-210

Author(s):

Xiu Mei Xu ◽

Tao Zheng ◽

Mohamed Saib ◽

Farid Sebaai ◽

Jeroen van de Kerkhove ◽

...

Keyword(s):

Mechanical Property ◽

Quantitative Analysis ◽

Aspect Ratio ◽

Analysis Techniques ◽

The Past ◽

Drying Techniques ◽

Wet Processing ◽

Different Dimensions ◽

Wafer Test ◽

Collapse Rate

Over the past decade, many advanced drying techniques have been developed to reduce and prevent pattern collapse of high aspect ratio (HAR) structures after wet processing. However, different dimensions, profiles and materials of HAR structures used in literature make it difficult to compare the efficiency of different drying processes. In this work, standard 300 mm wafer test structures, characterization and analysis techniques have been developed for quantitative analysis of pattern collapse rate as a function of the intrinsic mechanical property of HAR structures. Such standardized single wafer evaluations are important for benchmarking different drying techniques.

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