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Nicola Relph and Lee Herrington

Context: Clinicians require portable, valid, and cost-effective methods to monitor knee joint-position-sense (JPS) ability. Objective: To examine the criterion-related validity of image-capture JPS measures against an isokinetic-dynamometer (IKD) procedure. Design: Random crossover design providing a comparison of knee JPS measures from image capture and IKD procedures. Participants: 10 healthy participants, 5 female, age 28.0 ± 13.29 y, mass 60.3 ± 9.02 kg, height 1.65 ± 0.07 m, and 5 male, 29.6 ± 10.74 y, mass 73.6 ± 5.86 kg, height 1.75 ± 0.07 m. Main Outcome Measures: The dependent variables were absolute error scores (AES) provided by 2 knee directions (flexion and extension). The independent variables were the method (image capture and IKD). Results: There was no significant difference between clinical and IKD AED into knee-extension data (P = .263, r = 0.55). There was a significant difference between clinical and IKD AES into knee-flexion data (P = .016, r =.70). Conclusions: Analysis of photographic images to assess JPS measurements using knee flexion is valid against IKD techniques. However, photo-analysis measurements provided a lower error score using knee-extension data and thus may provide an optimal environment to produce maximal knee JPS acuity. Therefore, clinicians do not need expensive equipment to collect representative JPS ability.

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Lee Herrington

Context:

Authors have investigated knee joint-position sense (JPS) in non-weight-bearing open kinetic chain (OKC) manner, but few have investigated JPS during closed kinetic chain (CKC) weight-bearing activities or the relationship between these two.

Objective:

To investigate the relationship between knee JPS during OKC and CKC maneuvers.

Design:

2-group (men and women) repeated-measures.

Setting:

Biomechanics laboratory.

Participants:

80 asymptomatic subjects.

Interventions:

None.

Main Outcome Measure:

Absolute error score of knee JPS during 2 conditions, a CKC squat or OKC knee-flexion maneuver.

Results:

Statistical analysis by 2-way ANOVA showed sex not to have a significant effect on error score (P = .475), but statistically significant differences between error scores occurred during the 2 tests (P = .0001), the CKC test producing lower error scores (group mean absolute error score OKC [5.6° ± 4.3°] and CKC [2.8° ± 2.4°]), with the absence of a correlation between scores of each test (r = .1).

Conclusion:

Testing JPS in a CKC scenario would seem appropriate—the ability is greatest (least errors), and conversely any deficits might be most obvious.

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Sivan Almosnino, David Kingston and Ryan B. Graham

The purpose of this investigation was to assess the effects of stance width and foot rotation angle on three-dimensional knee joint moments during bodyweight squat performance. Twenty-eight participants performed 8 repetitions in 4 conditions differing in stance or foot rotation positions. Knee joint moment waveforms were subjected to principal component analysis. Results indicated that increasing stance width resulted in a larger knee flexion moment magnitude, as well as larger and phase-shifted adduction moment waveforms. The knee’s internal rotation moment magnitude was significantly reduced with external foot rotation only under the wide stance condition. Moreover, squat performance with a wide stance and externally rotated feet resulted in a flattening of the internal rotation moment waveform during the middle portion of the movement. However, i is speculated that the differences observed across conditions are not of clinical relevance for young, healthy participants.

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Robert L. Barrack, Peter J. Lund and Harry B. Skinner

Extensive histological studies have now confirmed a definite link between the anterior cruciate ligament (ACL) and the central nervous system. Preliminary histological evidence indicates that this neurological connection may be restored following reconstruction utilizing a free graft. In spite of this apparent graft reinnervation, clinical studies indicate that proprioception in the reconstructed knee probably remains inferior to that of the contralateral normal knee. A number of abnormalities of gait, reflexes, and muscle firing patterns have been discovered following an ACL tear. The degree to which a successful repair or reconstruction corrects these abnormalities remains uncertain, but again it appears that some abnormalities remain even during normal walking. Increased activity of the hamstrings as well as of the vastus lateralis, tibialis anterior, and medial gastrocnemius seems to be an adaptive mechanism to stabilize the knee after ACL injury. These muscle firing patterns seem to be trainable to some degree and should be incorporated into postinjury and postsurgical rehabilitation protocols.

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Komeil Dashti Rostami, Aynollah Naderi and Abbey Thomas

motion. 20 – 22 Weakness in the GMED alters the forces acting on the knee joint and leads to aberrant biomechanics, such as a dynamic knee valgus position. 23 – 25 Despite numerous reports that diminished hip strength influences abnormal movements at the trunk, hip, and knee, 19 , 26 – 30 other

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Nicola Relph and Lee Herrington

Context: Knee joint-position sense (JPS) plays a critical role in controlled and stable joint movement. Poor ability to sense position of the knee can therefore increase risk of injury. There is no agreed consensus on JPS measurement techniques and a lack of reliability statistics on methods. Objective: To identify the most reliable knee JPS measurement technique using image capture. Design: Interexaminer, intraexaminer, and test-retest reliability of knee JPS measurements. Setting: Biomechanics laboratory. Participants: 10 asymptomatic participants. Interventions: None. Main Outcome Measures: Relative and absolute error scores of knee JPS in 3 conditions (sitting, prone, active) through 3 ranges of movement (10-30°, 30-60°, 60-90°), into 2 directions (flexion and extension) using both legs (dominant and nondominant) collected during 15 trials and repeated 7 d after the first data collection. Results: Statistical analysis by intraclass correlations revealed excellent interexaminer reliability between researchers (.98) and intraexaminer reliability within 1 researcher (.96). Test-retest reliability was highest in the sitting condition from a starting angle of 0°, target angle through 60-90° of flexion, using the dominant leg and absolute-error-score variables (ICC = .92). However, it was noted smallest detectable differences were a high percentage of mean values for all measures. Conclusions: The most reliable JPS measurement for asymptomatic participants has been identified. Practitioners should use this protocol when collecting JPS data during prescreening sessions. However, generalizability of findings to a class/group of clients exhibiting knee pathologies should be done with caution.

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Natalia Romero-Franco, Juan Antonio Montaño-Munuera and Pedro Jiménez-Reyes

Context: Knee joint-position sense (JPS) is a key parameter for optimum performance in many sports but is frequently negatively affected by injuries and/or fatigue during training sessions. Although evaluation of JPS may provide key information to reduce the risk of injury, it often requires expensive and/or complex tools that make monitoring proprioceptive deterioration difficult. Objective: To analyze the validity and reliability of a digital inclinometer to measure knee JPS in a closed kinetic chain (CKC). Design: The validity and intertester and intratester reliability of a digital inclinometer for measuring knee JPS were assessed. Setting: Biomechanics laboratory. Participants: 10 athletes (5 men and 5 women; 26.2 ± 1.3 y, 71.7 ± 12.4 kg; 1.75 ± 0.09 m; 23.5 ± 3.9 kg/m2). Intervention: Knee JPS was measured in a CKC. Main Outcome Measures: Absolute angular error (AAE) of knee JPS in a CKC. Results: Intraclass correlation coefficient (ICC) and standard error of the mean (SEM) were calculated to determine the validity and reliability of the inclinometer. Data showed that the inclinometer had a high level of validity compared with an isokinetic dynamometer (ICC = 1.0, SEM = 1.39, P < .001), and there was very good intra- and intertester reliability for reading the inclinometer (ICC = 1.0, SEM = 0.85, P < .001). Compared with AutoCAD video analysis, inclinometer validity was very high (ICC = 0.980, SEM = 3.46, P < .001) for measuring AAE during knee JPS in a CKC. In addition, the intertester reliability of the inclinometer for obtaining AAE was very high (ICC = .994, SEM = 1.67, P < .001). Conclusion: The inclinometer provides a valid and reliable method for assessing knee JPS in a CKC. Health and sports professionals could take advantage of this tool to monitor proprioceptive deterioration in athletes.

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Rosa M. Rodriguez, Ashley Marroquin and Nicole Cosby

and hearing a pop, resulting in progressive knee swelling and difficulty ambulating. The ACL is one of the major ligaments that provides stability to the knee joint by preventing anterior translation of the femur in the closed kinetic chain. 5 Therefore, most of the time, a ruptured ACL results in

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Akihiro Tamura, Kiyokazu Akasaka and Takahiro Otsudo

landing may cause ACL injuries. 9 Loads on knee joints during landings can be decreased by employing strategies to absorb landing stresses throughout the lower-extremities. Some researchers have measured the relative contributions of the lower-extremity joints for energy absorption during landing. 10

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Daniel J. Petit, John D. Willson and Joaquin A. Barrios

Efforts to compare different surface marker configurations in 3-dimensional motion analysis are warranted as more complex and custom marker sets become more common. At the knee, different markers can been used to represent the proximal shank. Often, two anatomical markers are placed over the femoral condyles, with their midpoint defining both the distal thigh and proximal shank segment ends. However, two additional markers placed over the tibial plateaus have been used to define the proximal shank end. For this experiment, simultaneous data for both proximal shank configurations were independently collected at two separate laboratories by different investigators, with one laboratory capturing a walking population and the other a running population. Common discrete knee joint variables were then compared between marker sets in each population. Using the augmented marker set, peak knee flexion after weight acceptance was less (1.2−1.7°, P < .02) and peak knee adduction was greater (0.7−1.4°, P < .001) in both data sets. Similarly, the calculated peak knee flexion moment was less by 15–20% and internal rotation moment was greater by 11–18% (P < .001). These results suggest that the calculation of knee joint mechanics are influenced by the proximal shank’s segment endpoint definition, independent of dynamic task, investigator, laboratory environment, and population in this study.