Summary

Age above 38 years and 9 months from complete rupture of the ACL cause lower blood supply and lower bone quality of subchondral bone.

Abstract

Anterior cruciate ligament injury is one of the most common knee injuries occurring in both professional athletes and amateurs. The actual knowledge does not take under the consideration the effects on the femoral bone after the rupture. Therefore, a group of researchers from Medical University of Lódz decided to perform the research. The aim of the study was to assess bone quality and the degree of blood supply to the femoral attachment of the anterior cruciate ligament on the femur.
The study involved mature patients diagnosed with ACL rupture. Before the procedure, the researchers obtained data from the patients regarding: gender, age, time from injury to surgery, smoking cigarettes and the level of the patient's activity after injury. During the cruciate ligament reconstruction surgery in patients, before drilling the femoral canal, a 4.5 mm bone block with a diameter of 3.5 mm and a length of 2 cm on average was collected using Synthes® Hollow Reamer. A block meeting the test criteria was collected in 50 patients. The block was subjected to decalcification, then it was divided into 3 equal blocks. A cross-section was made of each block, which was fixed in hematoxylin and eosin, as well as an immunohistochemical test for cells with the presence of CD34. The number of blood vessels and clusters of positive cells for CD34 per mm2 was counted using ImageJ ™. Bone tissue quality was also analyzed by counting the average and total number of tissue windows left by osteocytes. Finally the statistical analysis was performed.
The median waiting time for surgery was 9.5 months. Patients who had undergone surgery before 9 months showed an average number of 5 blood vessels per mm2 cross-section, while in patients who waited longer for the procedure the number was 2 vessels, a statistically significant difference (p <0.01). Similar statistical significance was observed when examining the number of clusters of cells stained with CD34 marker, on average 5 clusters in the group up to 9 months after injury, less than 3 in the group waiting longer for surgery. Bone quality deterioration is also reflected in the time of waiting for surgery - the first group average osteocyte density per mm2 is 74, the second group 54 (p <0.01). A statistically significant interaction was also observed between age and time from injury - where, firstly, there was a negative correlation of time from injury to vessel density, and secondly, the relationship would be stronger among people up to 38 years of age. than in people over 38 years (r = -0.659; p <0.001; over 38 years r = -0.523; p = 0.018) (Figure 2). The analyzes did not reveal the interactive relationship between sex and time from injury.
In summary, the waiting time for surgery has a significant impact on the blood supply and bone quality of the ACL attachment site. Age above 38 years and 9 months from complete rupture of the ligament may cause a longer healing period of the graft.