Controlled fracture of the medial wall versus structural autograft with bulk femoral head to increase cup coverage by host bone for total hip arthroplasty in osteoarthritis secondary to developmental dysplasia of the hip: a retrospective cohort study

Background Many methods have been proposed to increase cup coverage by host bone during primary total hip arthroplasty (THA) in hip osteoarthritis secondary to developmental dysplasia of the hip (DDH). However, there was no study comparing the results of controlled fracture of the medial wall with a structural autograft with a bulk femoral head. Methods Sixty-seven hips classified as Crowe II/III were retrospectively included in this cohort study, which consisted of 33 controlled fractures (group A) and 34 structural autografts (group B). The Harris Hip Scores (HHS) were recorded. The radiological assessments were analyzed. Also, complications are assessed. The paired-sample t test was used for data analysis before and after the operation, while the independent sample T test was used for the comparison between the two groups. The Pearson chi-square test or the Fisher exact test was used to analyze the qualitative comparative parameters. Kaplan-Meier was utilized in the analysis of survivorship with the end points as a revision for any component. Results All patients were reconstructed acetabulum at the anatomical location. HHS increased greatly for both groups (p = 0.18). No statistic difference was observed for the two groups in postoperative leg-length discrepancy (0.51 ± 0.29 cm for group A and 0.46 ± 0.39 cm for group B, p = 0.64 ), postoperative height of the hip center (2.25 ± 0.42 cm for group A and 2.09 ± 0.31 cm for group B, p = 0.13), and inclination of the cup (39 ± 4° for group A and 38 ± 3° for group B, p = 0.65 ). The rate of cup coverage for group B (94 ± 2%) was better than for group A (91 ± 5%), (p = .009). The rate of cup protrusio was 48 ± 4% for group A. For both groups, no statistical difference was observed in the cup diameter (p > .05), while group A showed less operation time than group B (p < .001). No complications were observed at the latest follow-up. Conclusion Controlled fracture of the medial wall to increase cup coverage by host bone at the anatomical location can act as an alternative technique for DDH Crowe II/III with the advantage of shorter operation time and less technically demanding.

Controlled fracture of medial wall versus structural autograft with bulk femoral head to increase cup coverage by host bone for total hip arthroplasty in osteoarthritis secondary to developmental dysplasia of hip: a retrospective cohort study

Background: Many methods have been proposed to increase cup coverage by host bone during primary total hip arthroplasty (THA) in hip osteoarthritis secondary to developmental dysplasia of hip (DDH). However, there was no study comparing results of controlled fracture of medial wall with structural autograft with bulk femoral head. Methods: 67 hips classified as Crowe II/III were retrospectively included in this cohort study, which consisted of 33 controlled fracture (group A) and 34 structural autograft (group B). The Harris Hip Scores (HHS) was recorded. The radiological assessments were analyzed. Also, complications are assessed. The paired sample t test was used for data analysis before and after operation, while independent sample T test was used for the comparison between the two groups. The Pearson chi-square test or Fisher exact test was used to analyze the qualitative comparative parameters. Kaplan-Meier was utilized in the analysis of survivorship with the end points as a revision for any component.Results: All patients were reconstructed acetabulum at anatomical location. HHS increased greatly for both groups (P=0.18). No statistic difference was observed for two groups in postoperative leg-length discrepancy ((0.51±0.29) cm for group A and (0.46±0.39) cm for group B, P=0.64 ), postoperative height of hip center ((2.25±0.42) cm for group A and (2.09±0.31) cm for group B, P=0.13), inclination of cup ((39±4)°for group A and (38±3)°for group B, P=0.65 ). The rate of cup coverage for group B ((94±2)% ) was better than group A ((91±5)%), ( P=.009). Rate of cup protrusio was (48±4)% for group A. For both groups, No statistic difference was observed in cup diameter (P＞.05), while group A showed less operation time than group B (P＜.001). No complications were observed at the latest follow-up. Conclusion: Controlled fracture of medial wall to increase cup coverage by host bone at anatomical location can act as an alternative technique for DDH Crowe II/III with advantage of shorter operation time and less technically demanding.

Controlled Fracture of Medial Wall Versus Structural Autograft With Bulk Femoral Head to Increase Cup Coverage by Host Bone for Total Hip Arthroplasty in Osteoarthritis Secondary to Developmental Dysplasia of Hip: a Retrospective Cohort Study

Background: Many methods have been proposed to increase cup coverage by host bone during primary total hip arthroplasty (THA) in hip osteoarthritis secondary to developmental dysplasia of hip (DDH). However, there was no study comparing results of controlled fracture of medial wall with structural autograft with bulk femoral head. Methods: 67 hips classified as Crowe II/III were retrospectively included in this cohort study, which consisted of 33 controlled fracture (group A) and 34 structural autograft (group B). The Harris Hip Scores (HHS) was recorded. The radiological assessments were analyzed. Also, complications are assessed. The paired sample t test was used for data analysis before and after operation, while independent sample T test was used for the comparison between the two groups.Results: All patients were reconstructed acetabulum at anatomical location. HHS increased greatly for both groups (P=0.18). No statistic difference was observed for two groups in postoperative leg-length discrepancy ((0.51±0.29) cm for group A and (0.46±0.39) cm for group B, P=0.64 ), postoperative height of hip center ((2.25±0.42) cm for group A and (2.09±0.31) cm for group B, P=0.13), inclination of cup ((39±4)°for group A and (38±3)°for group B, P=0.65 ). The rate of cup coverage for group B ((94±2)% ) was better than group A ((91±5)%), ( P=.009). Rate of cup protrusio was (48±4)% for group A. For both two groups, no complications were observed at the latest follow-up. Conclusion: Controlled fracture of medial wall to increase cup coverage by host bone at anatomical location can act as an alternative technique for DDH Crowe II/III with advantage of shorter operation time and less technically demanding.

Regional Variability in Lithic Miniaturization and the Organization of Technology in Late Glacial Southern Africa (~18-11 kcal BP)

Miniaturized stone tools made by controlled fracture are reported from nearly every continent where archaeologists have systematically looked for them. While similarities in technology are acknowledged between regions, few detailed inter-regional comparative studies have been conducted. Our paper addresses this gap, presenting results of a comparative lithic technological study between Klipfonteinrand and Sehonghong – two large rock shelters in southern Africa. Both sites contain Late Glacial (~18-11 kcal BP) lithic assemblages, though they are located in regions with different geologies, climates and environments. Results demonstrate that lithic miniaturization manifests differently in these different regions. Both assemblages provide evidence for small blade production, though key differences exist in terms of the specific technological composition of this evidence, the raw materials selected, the role played by bipolar reduction and the manner in which lithic reduction was organized. Patterned variability of this nature demonstrates that humans deployed miniaturized technologies strategically in relation to local conditions.

Mechanism of irregular crack-propagation in thermal controlled fracture of ceramics induced by microwave

Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.

The role of temperature in the rigidity-controlled fracture of elastic networks

Thermal fluctuations have a rigidity-dependent effect on the failure response of central-force spring networks, promoting diffuse damage via the delocalization of stress.