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Mason D. Smith and David R. Bell

Context:

Anterior cruciate ligament (ACL) reconstruction is the standard of care for individuals with ACL rupture. Balance deficits have been observed in patients with ACL reconstruction (ACLR) using advanced posturography, which is the current gold standard. It is unclear if postural-control deficits exist when assessed by the Balance Error Scoring System (BESS), which is a clinical assessment of balance.

Objective:

The purpose of this study is to determine if postural-control deficits are present in individuals with ACLR as measured by the BESS.

Participants:

Thirty participants were included in this study. Fifteen had a history of unilateral ACLR and were compared with 15 matched controls.

Interventions:

The BESS consists of 3 stances (double-limb, single-limb, and tandem) on 2 surfaces (firm and foam). Participants begin in each stance with hands on their hips and eyes closed while trying to stand as still as possible for 20 s.

Main Outcome Measures:

Each participant performed 3 trials of each stance (18 total), and errors were assessed during each trial and summed to create a total score.

Results:

We observed a significant group × stance interaction (P = .004) and a significant main effect for stance (P < .001). Post hoc analysis revealed that the ACLR group had worse balance on the single-leg foam stance than did controls. Finally, the reconstructed group had more errors when total BESS score was examined (P = .02).

Conclusions:

Balance deficits exist in individuals with ACLR as measured by the BESS. Total BESS score was different between groups. The only condition that differed between groups was the single-leg stance on the unstable foam surface.

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Lindsey K. Lepley, Abbey C. Thomas, Scott G. McLean and Riann M. Palmieri-Smith

Context:

As individuals returning to activity after anterior cruciate ligament reconstruction (ACLr) likely experience fatigue, understanding how fatigue affects knee-muscle activation patterns during sport-like maneuvers is of clinical importance. Fatigue has been suggested to impair neuromuscular control strategies. As a result, fatigue may place ACLr patients at increased risk of developing posttraumatic osteoarthritis (OA).

Objective:

To determine the effects of fatigue on knee-muscle activity post-ACLr.

Design:

Case control.

Setting:

University laboratory.

Participants:

12 individuals 7–10 mo post-ACLr (7 male, 5 female; age 22.1 ± 4.7 y; 1.8 ± 0.1 m; mass 77.7 ± 11.9 kg) and 13 controls (4 male, 9 female; age 22.9 ± 4.3 y; 1.7 ± 0.1 m; mass 66.9 ± 9.8 kg).

Interventions:

Fatigue was induced via repetitive sets of double-leg squats (n = 8), which were interspersed with sets of single-leg landings (n = 3), until squats were no longer possible.

Main Outcome Measures:

2 × 2 repeated-measures ANOVA was used to detect the main effects of group (ACLr, control) and fatigue state (prefatigue, postfatigue) on quadriceps:hamstring cocontraction index (Q:H CCI).

Results:

All subjects demonstrated higher Q:H CCI at prefatigue compared with postfatigue (F 1,23 = 66.949, P ≤ .001). Q:H CCI did not differ between groups (F 1,23 = 0.599, P = .447).

Conclusions:

The results indicate that regardless of fatigue state, ACLr individuals are capable of restoring muscle-activation patterns similar to those in healthy subjects. As a result, excessive muscle cocontraction, which has been hypothesized as a potential mechanism of posttraumatic OA, may not contribute to joint degeneration after ACLr.

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Jesse C. Christensen, Laura R. Goldfine and Hugh S. West

Study Design:

Prospective randomized clinical trial.

Methods and Measures:

Thirty-six patients who had a primary anterior cruciate ligament reconstruction (ACL-R) with a semitendinosus-gracilis (STG) autograft from a single orthopedic surgeon were prospectively randomized into 2 groups. Nineteen patients were randomized to the aggressive group (53% male, mean age 30.1 + 10.5 y) and 17 to the nonaggressive group (88% male, mean age 33.1 + 10.9 y). Impairment measures of anteroposterior (A-P) knee laxity, range of motion (ROM), and peak isometric force (PIF) values were obtained 12 wk postoperatively. Subjective response to the International Knee Documentation Committee knee form (IKDC) was collected 1, 12, and 24 wk postoperatively. One-way ANOVA was used to analyze differences between groups at 12 wk for A-P knee laxity, ROM, and PIF. Differences between the groups for the IKDC scores were determined using 1-way ANOVA with repeated measures 1, 12, and 24 wk postoperatively. Bonferroni adjustment was used for multiple comparisons.

Results:

There were no differences between the groups for the baseline characteristics (P > .05). There was no difference found between the groups in respect to A-P knee laxity, ROM, or PIF at 12 wk (P > .05). Further analysis also showed no significant differences in the IKDC scores between groups at 12 or 24 wk (P > .05).

Conclusions:

No differences were found between early aggressive and nonaggressive rehabilitation after an isolated ACL-R using STG autografts for the primary outcomes of A-P knee laxity and subjective IKDC score. In addition, no differences were observed for secondary outcomes between groups for differences in ROM and PIF values.

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Rod A. Harter, Louis R. Osternig and Kenneth M. Singer

This study evaluated knee joint position sense in the ACL-reconstructed and contralateral normal knees of 48 male and female subjects (M age 27.6 ± 6.9 yrs). Subjects were blindfolded and tested on their ability to actively reproduce five passively placed knee positions at 5° intervals between 35 and 15° of knee flexion. Mean algebraic target angle error and mean absolute error values were measured in degrees. The grand mean absolute error for the postsurgical knees at all positions was 5.4 ± 3.2°, compared with 5.2 ± 2.7° for the normal contralateral knees. There were no significant differences in knee joint position sense between the postsurgical and normal contralateral limbs at any of the five positions tested. Pivot shift, anterolateral rotatory instability, and Lachman test results were poorly correlated with knee joint position sense. The results suggest that if knee joint position sense was indeed disrupted by ACL injury and reconstructive surgery, related sensory mechanisms compensated for any proprioceptive loss prior to the minimum 2-yr postsurgical follow-up period employed in our study.

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Jatin P. Ambegaonkar, Sandra J. Shultz, David H. Perrin and Mark R. Schulz

Edited by Mary Barnum

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Kevin E. Wilk, Naiquan Zheng, Glenn S. Fleisig, James R. Andrews and William G. Clancy

Closed kinetic chain exercise has become popular in rehabilitation of the ACL patient. While many clinicians agree on the benefits of closed kinetic chain exercise, there is great discrepancy as to which exercises fit this category. This discrepancy stems from the fact that the kinetic chain concept was originally developed using mechanical engineering concepts and not human kinesiology. In this paper, the kinetic chain concept is redefined in a continuum of lower extremity exercises from closed kinetic chain to open kinetic chain. The placement of an exercise in this continuum is based upon joint kinematics, quadriceps and hamstring muscle activity, cruciate ligament stress, and joint weight-bearing load. An understanding of these factors can help the clinician design a comprehensive and effective rehabilitation program for the ACL patient.

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Brian Powell, Wendy Hurd and Lynn Snyder-Mackler

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Gregory D. Myer, Kevin R. Ford and Timothy E. Hewett

Edited by Tricia J. Hubbard