Preoperative Loss of Knee Extension Affects Knee Extension Deficit in Patients After Anterior Cruciate Ligament...

Loss of knee extension (LOE) after anterior cruciate ligament reconstruction (ACLR) is associated with limited knee joint function and increased risk for knee osteoarthritis.

Preoperative LOE will affect postoperative LOE for up to 12 months after ACLR.

Cohort study; Level of evidence, 2.

Included were patients who underwent anatomic ACLR between June 2014 and December 2018. In all patients, the postoperative rehabilitation protocol was the same. A heel height difference (HHD) ≥2 cm between the affected and the contralateral leg was used as a measure of LOE. Based on preoperative HHD, patients were divided into LOE and no-LOE groups. The HHD was reevaluated at 1, 3, 4, 6, 9, and 12 months postoperatively. Proportional hazards analysis was used, with the dependent variable being whether a postoperative HHD <2 cm was achieved; the independent variables being the presence or absence of preoperative LOE; and the adjusted variables being age, sex, time to surgery, and presence of meniscal sutures.

A total of 389 patients (208 female, 181 male; median age, 21.0 years) were included in the study. There were 55 patients in the LOE group and 334 patients in the no-LOE group. The incidence of LOE at 12 months after ACLR was 13.8% in the no-LOE group and 38.2% in the LOE group (P < .001), with an absolute risk difference of 24.4%. The hazard ratio for achieving postoperative HHD <2 cm was 2.79 for the LOE group versus the no-LOE group (P < .001).

Patients with preoperative LOE were nearly 3 times more likely than those without LOE to have LOE at 12 months after ACLR.