Changes in Local Bone Mineral Density in Patients With Rupture of the Anterior Cruciate Ligament and Its Guiding Significance for Treatment

Background:It is recognized that there are many factors that affect the outcomes of anterior cruciate ligament(ACL) reconstruction. However, there were few studies on the effect of local bone conditions on the reconstruction of the ACL. This study aimed to summarize the changes in local bone mineral density (BMD) of the knee after rupture of the ACL and to guide the treatment. Methods: Eighty patients with ACL rupture treated in our department from January 2017 to April 2019 were routinely measured for local bone mineral density before surgery, and according to the bone mineral density, the appropriate method of ligament reconstruction and fixation under arthroscopy was selected: if the local bone mineral density of the affected knee was not significantly lower than that of the healthy side, squeeze fixation was used, and suspension fixation was used when the local bone mineral density of the affected knee was lower than that of the healthy knee. The conditions of tunnel cutting or screw splitting and tunnel enlargement or screw pull-out were observed during the operation, and the fixation mode was adjusted in time according to the situation. The function of the knee joint was evaluated regularly by physical examination, imaging data, the IKDC scale and the Lysholm score table after the operation. Results:A total of 80 patients with unilateral ACL rupture were included in this group. There were 44 males and 36 females. Sixty-eight patients had decreased bone mineral density in the affected knee. The bone mineral density of patients with a history of more than 3 months was lower than that of patients with a history of less than 3 months. Tunnel enlargement and screw pull-out occurred in 2 patients, screw splitting occurred in 1 patient, and no adverse conditions occurred in the rest of the patients. In 3 patients, the fixation mode was adjusted in time during the operation. The patients were followed for 12 months (mean 20.65±5.12 months). The IKDC score increased from 43.07±2.66 before the operation to 89.17±3.28 at the final follow-up, and the Lysholm score increased from 43.49±2.38 to 89.67±2.97. Conclusions:The measurement of local bone mineral density before surgery is of guiding significance for the selection of reconstruction and fixation of the ACL. It is recommended that patients undergo surgical reconstruction within 3 months after injury. When the bone mineral density of the affected knee decreases significantly to at least 70% lower than that of the healthy side, suspension fixation is recommended and the brace fixation time is prolonged.