Histomorphological Investigation of Microfracture Location in a Rabbit Osteochondral Defect Model.

BACKGROUND: Microfracture is the most common treatment for cartilage defects of the knee. In microfracture surgery, holes are randomly drilled into the subchondral bone. The effect of the hole's location on its interaction with the cartilage defect site and its influence on the healing process is currently uncertain. PURPOSE: To investigate the effects of different microfracture locations on healing in a rabbit knee osteochondral defect model. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 29 adult New Zealand White rabbits were divided into 5 groups. In the healthy cartilage control group (n = 5), no surgical procedure was performed. Cylindrical full-thickness cartilage defects (5 × 3 mm) were created in the patellar groove of the remaining 24 rabbits. In the defect control group (n = 6), only the defect was created. A microfracture was performed at the 12-o'clock position (group peripheral single; n = 6), centrally (group central; n = 6), and at the 12- and 6-o'clock positions (group peripheral double; n = 6) of the defect. The animals were sacrificed after 8 weeks. Cartilage healing was evaluated by International Cartilage Regeneration & Joint Preservation Society (ICRS) score, modified O'Driscoll score, immunohistochemical analysis (type 1 collagen, type 2 collagen, and aggrecan), and scanning electron microscopy analysis. RESULTS: In group peripheral double, better cartilage healing was observed in all parameters compared with the other groups (P < .05). Group peripheral double had the greatest amount of filling, with 79% of the defect area filled with fibrocartilage repair tissue. Group peripheral single demonstrated filling of 73% of the defect area, group central 56%, and the defect control group 45%. The ICRS score was significantly higher in group peripheral single compared with group central and the defect control group. Type 2 collagen and aggrecan immunoreactivity were significantly stronger in group central than group peripheral single and the defect control group (P < .05). CONCLUSION: Microfracture performed at the peripheral margin of the defect had better filling characteristics in a rabbit model. This study suggests that interaction of pluripotent cells released from the microfracture site with the intact cartilage may enhance the quality of the repair tissue. CLINICAL RELEVANCE: The location of microfracture holes in relation to the peripheral border of the osteochondral defect (to the intact cartilage) is important in both the quality and the quantity of the newly formed repair tissue.

Accuracy of point-of-care ultrasound for determining the adequacy of pediatric forearm fracture reductions.

BACKGROUND: The objective of the present study was to the determine the accuracy of point-of-care ultrasound (POCUS) in assessing closed reduction (CR) of pediatric forearm fractures in a pediatric emergency setting. METHODS: After determination of the need for CR using X-ray images by an orthopedic consultant, POCUS examinations were performed just before and after the reduction attempt. The transducer was positioned longitudinally over the dorsal, volar, and lateral surfaces of the radius and ulna to view the fracture site. The presence of angulation, displacement, or bayonetting of the fracture fragments was recorded. The adequacy of realignment according to the POCUS and the orthopedic consultant's final determination were recorded. RESULTS: Sixty-two patients were enrolled in the study and 96 bones were evaluated. The sensitivity and specificity of POCUS for adequacy of CR were 95.8% [95% confidence interval (CI): 88.3-99.1)] and 95.8% (95% CI: 78.8-99.8), the positive predictive value was 98.5% (95% CI: 91.0-99.7), and the negative predictive value was 88.4% (95% CI: 71.6-95.8). The corresponding positive and negative likelihood ratios were 23 (3.37-156.77) and 0.04 (0.01-0.12). There was high agreement between POCUS and X-ray images for predicting adequacy of CR [κ: 0.892 (±0.053)]. There was also a significant correlation between POCUS and X-ray measurements of angulation and displacement performed before and after CR, respectively (p < 0.001). CONCLUSION: Our study has reported the successful use of POCUS for the management of pediatric forearm fractures in a pediatric emergency department. Point-of-care ultrasound can minimize radiation exposure and appears to be an alternative and accurate tool for reduction attempts.