Lower Limb Stability With ACL Impairment

Abstract

Study Design: Repeated measures (3 separate day sessions) to determine test reliability; single-session repeated measures to compare stability between limbs. Objectives: To develop a functional test measuring dynamic stability that is capable of differentiating between the injured and uninjured lower limb in 2 populations: (1) people with anterior cruciate ligament deficiency (ACLd) and (2) people with anterior cruciate ligament reconstruction (ACLr), and to establish the reliability of this test. Background: Many functional tests of the lower limb used by clinicians, such as the 1-legged hop for distance, the 1-legged hop for time, the vertical jump, the triple hop for distance, shuttle run, and single-limb standing, do not allow the clinician to discern differences between function in the injured and uninjured limbs. Methods and Measures: Twenty-five nonimpaired subjects (14 men, 11 women, aged 31.2 2 9.1 years), 11 subjects with ACLr (9 men, 2 women, aged 26.3 2 10.4 years), and 13 subjects with ACLd (5 men, 8 women, aged 40.4 2 12.6 years) were tested. Twelve nonimpaired subjects participated in 3 testing sessions to determine the reliability of the force plate measures. Ground reaction forces (vertical, medial-lateral, and anterior-posterior) were measured while the subjects performed 1-legged hop and stepdown tests onto a force plate. Stability was defined as the ability to transfer the vertical projection of the center of gravity to the supporting base and keep the knee still. A repeated-measures analysis of variance (2-factor; limbs by trials) was used to compare the stability between limbs. Resulb: The majority of the measures used to calculate dynamic stability were reliable. Moreover, the data provide normal standards of functional knee stability for stepdown and hop tests. In the step-down test, changes in vertical force did identify dysfunction in the injured limb (stabilization time = 1527 2 216 rns) compared to the uninjured limb (stabilization time = 892 2 498 ms) for subjects with ACLr. Conclusions: The normal standards may serve as a reference for comparing functional differences in ACLr or ACLd populations. The vertical force parameter during a step-down may be useful as an outcome measure to monitor progress during rehabilitation. ) Orfhop Sports Phys Ther l999;29:444-454.

Time series of ground reaction forces following a single leg drop jump landing in elite youth soccer players consist of four distinct phases

“…Since impact forces are high, DPSI emphasizes more the landing rather than the stabilizing phase [13]. Both TTS and DPSI have shown higher outcome values for subjects with chronic ankle instability [14][15][16], or with ACL reconstruction [17,18], compared to healthy controls. However, their applicability with regard to injury risk and monitoring of rehabilitation still needs to be elucidated [6,13,19,20].…”

Time to Stabilization of Anterior Cruciate Ligament–Reconstructed Versus Healthy Knees in National Collegiate Athletic Association Division I Female Athletes

“…Ten trials were completed on each limb. 24 Although these athletes were exposed regularly to strenuous activity, including jumping, a 1-minute rest was given between trials to avoid fatigue.…”

“…The time-to-stabilization (TTS) measurement technique is used to assess the time that participants take to attain a stable position after a jump-landing task, giving an indication of dynamic postural stability. Colby et al, 24 who were the first to study this technique, compared the stabilization times of unilateral ACL-deficient and ACLR knees with the contralateral healthy knees in recreationally active patients. They found that TTS was a reliable means for identifying a deficit in dynamic postural stability in those with ACL injury while performing a step-down task.…”

“…Often, neuromuscular deficits of the lower extremity are measured using static single-leg-stance positions. [17][18][19][20][21][22][23] Colby et al 24 suggested that a static position does not sufficiently challenge the neuromuscular system in recreating athletic activity or even activities of daily living. More dynamic types of activities, such as jump-landing tasks, might be a more accurate tool for assessment of the lower extremity neuromuscular system during single-limb activities.…”

Análise da simetria em tarefas motoras em sujeitos submetidos à reconstrução do ligamento cruzado anterior

“…Há, na literatura, uma série de trabalhos que têm investigado a simetria em tarefas unipedais, em sujeitos submetidos à reconstrução cirúrgica do LCA (Novak, Bach et al, 1996;Bach, Trdonsky et al, 1998;Colby, Hintermeister et al, 1999;Hoffman, Schrader et al, 1999;Rudroff, T., 2003;Gustavsson, Neeter et al, 2006). Em tarefas como o apoio unipedal, como o salto vertical unipedal, esses sujeitos tendem a apresentar déficits no membro operado em relação ao membro sadio.…”