Changes in local bone mineral density can guide the treatment plan for patients with rupture of the anterior cruciate ligament.

Background: Many factors affect the outcomes of anterior cruciate ligament (ACL) reconstruction surgery. However, few studies have examined the effects of local bone conditions on the reconstruction of the ACL. This study investigated the changes in the local bone mineral density (BMD) of the knee after rupture of the ACL with the view of using this information to guide treatment options.

Methods: Patients with ACL rupture treated in our department from January 2017 to April 2019 were enrolled in this study. Prior to surgery, local BMD measurements were obtained from all patients and used to determine the appropriate method of ligament fixation. If the local BMD of the affected knee was not significantly lower than that of the healthy side, extrusion fixation was conducted. If the BMD was significantly lower than that of the healthy knee, suspension fixation was applied. The conditions of tunnel cutting or screw splitting, and tunnel enlargement or screw pull-out were observed during the surgery. The post-surgical function of the knee joint was evaluated regularly by physical examination, imaging data, the IKDC scale score, and the Lysholm score.

Results: A total of 80 patients with unilateral ACL rupture were included. There were 64 males and 16 females. Decreased BMD was observed in the affected knee compared to the healthy knee for 68 patients. Patients with an ACL history of more than 3 months had lower BMD compared to 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. The fixation mode was adjusted in real-time during the surgery for 3 patients. All patients were followed up for at least 12 months (mean 20.65±5.12 months). The IKDC score increased from 43.07±2.66 pre-surgery to 89.17±3.28 at the final follow-up, and similarly, the Lysholm score increased from 43.49±2.38 pre-surgery to 89.67±2.97 post-surgery.

Conclusions: The measurement of local BMD before surgery may play a significant role in guiding the type of graft fixation. It is recommended that patients undergo surgical reconstruction within 3 months after injury.