Different bone bruise patterns observed on magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) rupture and lateral patellar dislocation may indicate different injury mechanism of knee. In order to investigate the typical bone bruising patterns after ACL rupture and patellar dislocation. In this study, 77 ACL rupture and 77 patellar dislocation patients’ knee MR images with bone bruises between August 2020 and March 2022at our institution were selected and analyzed, respectively. Sagittal and transverse planes images were used to determine the bone bruise location in the lateral-medial and superior-inferior directions of the MR images. The presence, location, and intensity of the bone bruises within specific compartments of the femur and tibial after ACL rupture and patellar dislocation were recorded. Relative bone bruise patterns of the ACL rupture and patellar dislocation were classified and analyzed. Results showed that there were 4 kinds of bone bruise (1-,2-,3-,4- bone bruises) patterns after ACL rupture. The most common two patterns after ACL rupture were 3- bone bruises (including lateral side of femur and both lateral and medial side of tibia, LF+BT; both lateral and medial side of femur and lateral side of tibia, BF+LT, medial side of femur and both lateral and medial side of tibia, MF+BT) followed by 4- bone bruises (both lateral and medial side of femur and tibia, BF+BT), 2- bone bruises (LF+LT, lateral side of femur and tibia; MF+LT, medial side of femur and lateral side of tibia; LF+MT, lateral side of femur and medial side of tibia; MF+MT, medial side of femur and tibia; 0+BT, both lateral and medial side of tibia;), and 1- bone bruise (0+LT, only lateral side of tibia). There was only 1 pattern bone bruise (latera femur and medial patella bone bruise) of patellar dislocation, the most common pattern of patellar dislocation was in the inferior medial patella and lateral anterior inferior femur. The results suggest that the pattern of bone bruise after ACL rupture and patellar dislocation is completely different. There were 4 kinds of bone bruise patterns after non-contact ACL rupture while there was only 1 kind of bone bruise pattern after patellar dislocation bone bruise patients which was in the inferior medial patella and lateral anterior inferior femur.

Different bone bruise patterns observed using magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) rupture and lateral patellar dislocation may indicate different knee injury mechanisms. In this study, 77 ACL ruptures and 77 patellar dislocations in knee MR images taken from patients with bone bruises at our institution between August 2020 and March 2022 were selected and analyzed. In order to determine typical bone bruising patterns following by ACL rupture and patellar dislocation, sagittal- and transverse-plane images were used to determine bone bruise locations in the directions of medial-lateral and superior-inferior with MR images. The presence, intensity, and location of the bone bruises in specific areas of the femur and tibial after ACL rupture and patellar dislocation were recorded. Relative bone bruise patterns after ACL rupture and patellar dislocation were classified. The results showed that there were four kinds of bone bruise patterns (1-, 2-, 3-, and 4- bone bruises) after ACL rupture. The most common two patterns after ACL rupture were 3- bone bruises (including the lateral femoral condyle and both the lateral-medial tibial plateau, LF + BT; both the lateral-medial femoral condyle and the lateral tibial plateau, BF + LT; and the medial femoral condyle and both the medial and lateral tibial plateau, MF + BT) followed by 4- bone bruises (both the lateral-medial femoral condyle and the tibial plateau, BF + BT), 2- bone bruises (the lateral femoral condyle and tibial plateau, LF + LT; the medial femoral condyle and the lateral tibial plateau, MF + LT; the lateral femoral condyle and the medial tibial plateau, LF + MT; the medial femoral condyle and the tibial plateau, MF + MT; both the lateral-medial tibial plateau, 0 + BT), and 1- bone bruise (only the lateral tibial plateau, 0 + LT). There was only a 1- bone bruise (the latera femoral condyle and medial patella bone bruise) for patellar dislocation, and the most common pattern of patellar dislocation was in the inferior medial patella and the lateral anterior inferior femur. The results suggested that bone bruise patterns after ACL rupture and patellar dislocation are completely different. There were four kinds of bone bruise patterns after non-contact ACL rupture, while there was only one kind of bone bruise pattern after patellar dislocation in patients, which was in the inferior medial patella and lateral anterior inferior femur.

Anterior cruciate ligament (ACL) rupture and patellar dislocation (PD) are common knee injuries. Dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) are widely used clinical diagnostic tools. The aim was to investigate the characteristics of knee bone mineral density (BMD) in patients with ACL rupture and PD and to explore the relationship between BMD and Hounsfield unit (HU) values. This prospective cross-sectional study included 32 ACL rupture and 32 PD patients assessed via DXA and CT. BMD and CT measurements were taken from regions of interest in the femoral and tibial condyles. Statistical analyses included t-tests and mixed-effects models. The results showed that BMD in the PD group was significantly lower than in the ACL group (p < 0.05). The HU values of cortical bone in the femur and tibia differed significantly between the ACL group and the PD group (p < 0.05). The BMD of the femur and tibia showed significant correlations with the HU values of cancellous bone and cortical bone (p < 0.05). The conclusion was that PD patients had lower BMD and HU values in the femur and tibia compared to patients with ACL ruptures, particularly in the cortical bone of the tibia, and there was a strong correlation between HU value and BMD.

In the present study, 24 rabbits were firstly used to evaluate the apoptosis index and matrix degeneration after untreated adult meniscal tears. Vertical tears (0.25 cm in length) were prepared in the avascular zone of the anterior horn. Specimens were harvested at 1, 3, 6, 12 weeks postoperatively. The apoptosis index around tear sites stayed at a high level throughout the whole follow-up period. The depletion of glycosaminoglycans (GAG) and aggrecan at the tear site was observed, while the deposition of COL I and COL II was not affected, even at the last follow-up of 12 weeks after operation. The expression of SOX9 decreased significantly; no cellularity was observed at the wound interface at all timepoints. Secondly, another 20 rabbits were included to evaluate the effects of anti-apoptosis therapy on rescuing meniscal cells and enhancing meniscus repair. Longitudinal vertical tears (0.5 cm in length) were made in the meniscal avascular body. Tears were repaired by the inside-out suture technique, or repaired with sutures in addition to fibrin gel and blank silica nanoparticles, or silica nanoparticles encapsulating apoptosis inhibitors (z-vad-fmk). Samples were harvested at 12 months postoperatively. We found the locally administered z-vad-fmk agent at the wound interface significantly alleviated meniscal cell apoptosis and matrix degradation, and enhanced meniscal repair in the avascular zone at 12 months after operation. Thus, local administration of caspase inhibitors (z-vad-fmk) is a promising therapeutic strategy for alleviating meniscal cell loss and enhancing meniscal repair after adult meniscal tears in the avascular zone.