Changes in proprioception at different time points following anterior cruciate ligament injury or reconstruction

PURPOSE: To investigate the changes in 30° and 60° position sense in patients with anterior cruciate ligament (ACL) injury at different time points after injury and reconstruction. METHODS: Patients were divided into six groups according to time after ACL injury and reconstruction: group A (ACL injury 1.5–6 months), group B (ACL injury 6–12 months), group C (ACL injury > 12 months), group D (postoperative ACL reconstruction 1–6 months), group E (postoperative ACL reconstruction > 6 months), and group F consisting of 14 healthy adults (control group). The ability of the affected leg to reproduce the same joint position during knee flexion was tested using active joint position sense assays to assess proprioception in both the lower extremities of the patient or between groups. RESULTS: Proprioception decreased rapidly during the early stages of ACL injury. Significant difference in the affected side at 30° compared to the healthy side (Group A: 4.70 (4.78, 9.00) vs 4.15 (3.35, 6.13), P = 0.03; Group B: 2.90 (0.48, 4.56) vs 8.30 (4.18, 10.43), P = 0.001; Group E: 6.25 (2.55, 11.60) vs 9.60 (3.90, 12.73), P = 0.009). However, no significant differences were detected for a double lower limb contrast of 60° (Group A: 5.1 (1.00, 8.00) vs 3.00 (0.75, 3.55), P = 0.044). Finally, the affected side of patients in groups C, D and E had significant differences in position perception at 30° compared with healthy subjects (P < 0.01), and the affected side of patients in groups C and E had significant differences in position sense at 60° compared with healthy subjects (P < 0.01). CONCLUSION: ACL injury had a greater impact on the patient's 30° position sense, with only a small impact for 60°. Further, the early and middle proprioception recovery stages after ACL injury were the best before surgery. Finally, proprioception recovery training should be performed soon after injury.