Disclosure(s): No financial relationships to disclose
Disclosure(s):
Maximilian M. Mueller, MD: No financial relationships to disclose
Objectives: To evaluate the risk for complications and functional improvement following perioperative knee aspiration for the treatment of AMI, pain reduction and improvement of range of motion (ROM) in the setting of anterior cruciate ligament (ACL) injury. Methods: All patients who underwent perioperative knee aspiration before or after ACL surgery, including ACL reconstruction, ACL primary repair (ACLPR), and Bridge-enhanced ACL Restoration (BEAR), between 2016 and 2025 were retrospectively included. A minimum follow-up of 4 weeks was required for inclusion.A subset of patients underwent bilateral, superficial electromyography (EMG) evaluation of the quadriceps muscle before (T0) and after aspiration (1-min: T1; 10min: T2) to assess reduction of AMI. Functional improvement after aspiration including reduction of level of pain (VAS), SANE, and ROM were recorded. Results: Among a total of 1,099 ACL-injured patients, 929 patients comprised 1,239 perioperative knee aspirations (preoperative: n=209; 1st postoperative week: n=870; 4-weeks postoperative: n=160), with a aspirated volume of 35+-19ml. No patient (0.0%) was lost to follow-up. Four (0.43%) perioperative complications were recorded (2 culture-positive infections). Logistic regression demonstrated that preoperative aspiration was not significantly associated with aspiration in the 1st(OR 1.24, 95% CI (0.82-1.85); p=0.307) or 4th week postoperatively (OR 1.28, 95% CI (0.84-1.90); p=0.248). Patients who underwent perioperative knee aspiration had a significantly lower rate of reoperations for arthrofibrosis (n=7; 0.8%) compared with those without aspiration (n=6; 3.5%); (p=0.019).Specific functional outcome was available in 27 patients. Patients reported an immidiate (T2), significant reduction in VAS (-1.0+-1.8; p=0.002), improvement of SANE (+1.7+-1.4; p<0.001) and ROM (flexion, +16.9°+-11.6°; p<0.001). In 15 patients (55.6%), a significant reduction in AMI was observed between T0, T1, and T2 (vastus medialis: p=0.038; vastus lateralis: p=0.030; rectus femoris: p=0.344). The type of surgical procedure was a significant predictor for improvement of AMI (p<0.001), while patient age, sex, aspiration volume, VAS, and SANE score were not significantly correlated (p>0.1). Conclusions: Perioperative knee aspiration following ACL injury did not significantly increase complication risk compared to rates reported in the literature, while majority of patients experienced an immediate, significant improvement of knee function including a reduction of pain, increase of ROM, and reduction of AMI. The findings suggest a potential protective effect of perioperative knee aspiration against development of arthrofibrosis; however, future studies are needed to confirm this association and clarify its clinical relevance.
