Evaluation of lower limb kinetics during gait, sprint and hop tests before and after anterior cruciate ligament reconstruction

Abstract

Background: The purpose of this study was to evaluate the functional status prior to and at different times after anterior cruciate ligament reconstruction (ACLR), and to analyze the changes in the kinetic patterns of the involved and uninvolved lower limb during gait, sprint and three hop tests.

Materials and methods: Seventy-four male patients with an ACL injury were included in the study. All patients performed a standardized kinetic protocol including gait, sprint and three hop tests (single-leg hop, drop vertical jump and vertical jump tests), preoperatively and at 3, 6, and 12 months after ACLR with a semitendinosus gracilis tendon autograft. Measurements were performed with two force plates. The lower limb symmetry index (LSI) was calculated to determine whether a side-to-side leg difference was classified as normal (LSI >90%) or abnormal (LSI <90%).

Results: The LSI presented high values (>90%) at almost all times before and after ACLR in gait, sprint and single-leg hop tests (p < 0.005), with a tendency to increase postoperatively. A lower LSI was observed (<90%) in tests where both extremities were tested simultaneously, such as the drop vertical jump and vertical hop tests (p < 0.05).

Conclusion: We observed a tendency to increase symmetry restoration in the kinetics of the involved and uninvolved limb up to twelve months after ACLR, especially in those tests, in which, both limbs were tested individually (gait analysis, sprint and single-leg hop tests). Therefore, the isolation of the involved and uninvolved limb seems to be a critical component in the functional rehabilitation and evaluation of patients before and after ACLR.

Level of evidence: level III.

Keywords: ACL deficiency; ACL reconstruction; Hop tests; Knee kinetics; Semitendinosus gracilis autograft.

Fig. 1

a Gait test and kinetics graph. Subjects walked along a 5-m wooden walkway in which one of the force plates was embedded. Subjects were told to walk at a self-selected comfortable pace. b Sprint test and kinetics graph. The sprint test was performed with the patient standing on both platforms. After an initial trial, they were instructed to sprint as fast as possible for 5 s (CF control foot, IKF injured-knee foot, Max maximum, AP anterior-posterior)

Fig. 2

a Single-leg hop test and kinetics graph. The single-leg hop test for distance was performed as previously described [18]. Patients were instructed to stand on one leg and to position their toes against a mark on the floor. They were then instructed to hop forward as far as possible and to land on the same leg. b Drop vertical jump and kinetics graph. Subjects were instructed to drop off a 30-cm box and perform a maximum jump after landing. The box distance was adjusted so that the patient could land with one foot on each platform. c Vertical hop test and kinetics graph. Vertical hop test was performed (Fig. 2c) with the patient standing on both platforms and being instructed to hop using his arms as countermovement. Max maximum

Fig. 3

Gait kinetics, a contact time, b single-leg stance vertical force, c maximum anterior and posterior forces, d anterior posterior shifting point. IKN injured-knee foot, CF control foot, Pre-op preoperatively

Fig. 4

a Sprint kinetics, b single-leg hop test kinetics, c drop vertical jump kinetics, d vertical hop test kinetics. IKF injured-knee foot, CF control foot, Pre-op preoperatively