Comparison of Limb Loading Characteristics and Subjective Functional Outcomes Between Sexes After Anterior Cruciate Ligament Reconstruction.

CONTEXT

Anterior cruciate ligament reconstruction (ACLR) patients commonly adopt poor movement patterns that potentially place them at an increased risk for reinjury if untreated. Limb loading characteristics during functional tasks can highlight movement compensations.

OBJECTIVE

To examine loading symmetry during a bilateral bodyweight squatting task between sexes, compare loading metrics between limbs and sexes, and describe the relationship between loading metrics and patient-reported outcomes (PROs) after ACLR.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

One hundred forty-two patients (71 male, 71 female, age = 24.4 ± 11.10 years) with a primary, unilateral, uncomplicated ACLR completed a squatting assessment and PRO measures at approximately 5.2 months post-ACLR.

MAIN OUTCOME MEASURE(S): Normalized limb loading peak force (N/kg) and unilateral cumulative load (%) were collected bilaterally during the squatting task. Limb symmetry index (%) was calculated for normalized peak force. First, we compared limb loading symmetry (%) between sexes using an independent-samples t test. Second, we assessed differences in limb loading metrics between limbs and sexes via an analysis of covariance. Third, we used Spearman ρ correlations to determine the relationship between limb loading metrics and PROs.

RESULTS

The majority of individuals (91 of 142, 64.1%) offloaded their ACLR limb (ACLR = 6.6 ± 1.56 N/kg, contralateral = 7.3 ± 1.61 N/kg, P < .001). Females significantly offloaded their ACLR limb (ACLR = 6.3 ± 1.38 N/kg, contralateral = 7.2 ± 1.62 N/kg, P < .001) whereas males did not significantly offload their ACLR limb (ACLR = 6.98 ± 1.65 N/kg, contralateral = 7.4 ± 1.60 N/kg, P = .07). Weak relationships were observed (Ρ value range: -.23 to .19) across limb loading metrics and PROs.

CONCLUSIONS

Individuals approximately 5 months after ACLR, on average, offloaded their ACLR limb compared with the contralateral limb. Patients' tendency to offload their weight during a squat was influenced by sex. Relationships between limb loading metrics and PROs indicate patients who load their limbs disproportionately have a lower perception of their capability to complete activities of daily living and lower subjective knee function.