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Loading Patterns of the Posterior Cruciate Ligament in the Healthy Knee: A Systematic Review

View Article: PubMed Central - PubMed

ABSTRACT

Background: The posterior cruciate ligament (PCL) is the strongest ligament of the knee, serving as one of the major passive stabilizers of the tibio-femoral joint. However, despite a number of experimental and modelling approaches to understand the kinematics and kinetics of the ligament, the normal loading conditions of the PCL and its functional bundles are still controversially discussed.

Objectives: This study aimed to generate science-based evidence for understanding the functional loading of the PCL, including the anterolateral and posteromedial bundles, in the healthy knee joint through systematic review and statistical analysis of the literature.

Data sources: MEDLINE, EMBASE and CENTRAL

Eligibility criteria for selecting studies: Databases were searched for articles containing any numerical strain or force data on the healthy PCL and its functional bundles. Studied activities were as follows: passive flexion, flexion under 100N and 134N posterior tibial load, walking, stair ascent and descent, body-weight squatting and forward lunge.

Method: Statistical analysis was performed on the reported load data, which was weighted according to the number of knees tested to extract average strain and force trends of the PCL and identify deviations from the norms.

Results: From the 3577 articles retrieved by the initial electronic search, only 66 met all inclusion criteria. The results obtained by aggregating data reported in the eligible studies indicate that the loading patterns of the PCL vary with activity type, knee flexion angle, but importantly also the technique used for assessment. Moreover, different fibres of the PCL exhibit different strain patterns during knee flexion, with higher strain magnitudes reported in the anterolateral bundle. While during passive flexion the posteromedial bundle is either lax or very slightly elongated, it experiences higher strain levels during forward lunge and has a synergetic relationship with the anterolateral bundle. The strain patterns obtained for virtual fibres that connect the origin and insertion of the bundles in a straight line show similar trends to those of the real bundles but with different magnitudes.

Conclusion: This review represents what is now the best available understanding of the biomechanics of the PCL, and may help to improve programs for injury prevention, diagnosis methods as well as reconstruction and rehabilitation techniques.

No MeSH data available.


Average force patterns of the PCL during knee flexion with and without Posterior Tibial Load (PTL).Included articles in this graph: in vitro force in passive flexion [12, 13, 20, 62, 63, 86–89, 91], in situ force in passive flexion [9], modelling force in passive flexion [36, 75, 84], in vitro force with 100 N PTL [12, 13, 20, 86–88, 96, 97], in situ force with 100 N PTL [17] and in situ force with 134 N PTL [8, 15, 16, 18, 93–95, 98, 105].
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pone.0167106.g005: Average force patterns of the PCL during knee flexion with and without Posterior Tibial Load (PTL).Included articles in this graph: in vitro force in passive flexion [12, 13, 20, 62, 63, 86–89, 91], in situ force in passive flexion [9], modelling force in passive flexion [36, 75, 84], in vitro force with 100 N PTL [12, 13, 20, 86–88, 96, 97], in situ force with 100 N PTL [17] and in situ force with 134 N PTL [8, 15, 16, 18, 93–95, 98, 105].

Mentions: The majority of force data reported for the PCL during passive flexion has been acquired by the same research group using cadaveric knees and attaching a load cell to the isolated femoral attachment site of the ligament [12, 13, 20, 62, 63, 86–89]. In these studies, the knees were mounted in multi-degree of freedom jigs and manually moved through knee flexion. Based on their measurements, the PCL was found to be under low tension throughout flexion. The average tension in the PCL at full extension, 30° and 120° of flexion was approximately 15 (3), 4 (1) and 19 (5)N respectively (Fig 5). Smaller forces were reported by Wang and co-workers [91] who used a similar assessment technique, and were in a general agreement with a study using buckle force transducers implanted on the PM bundle [63]. Miyasaka and co-workers [62] detached the PCL from its femoral attachment site and reattached it to its anatomical position using a metal plate instrumented with 12 strain gauges. They reported only small forces in the PCL throughout the range of passive flexion with a maximum of 4 (1)N at 90°. In another study, a robotic manipulator together with a universal force sensor (UFS) was used to measure the in situ force of the PCL in nine cadaveric knees during passive flexion [9]. Except for 90° flexion, the force patterns of the PCL were close to the average force trend extracted from the data measured in vitro.


Loading Patterns of the Posterior Cruciate Ligament in the Healthy Knee: A Systematic Review
Average force patterns of the PCL during knee flexion with and without Posterior Tibial Load (PTL).Included articles in this graph: in vitro force in passive flexion [12, 13, 20, 62, 63, 86–89, 91], in situ force in passive flexion [9], modelling force in passive flexion [36, 75, 84], in vitro force with 100 N PTL [12, 13, 20, 86–88, 96, 97], in situ force with 100 N PTL [17] and in situ force with 134 N PTL [8, 15, 16, 18, 93–95, 98, 105].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120848&req=5

pone.0167106.g005: Average force patterns of the PCL during knee flexion with and without Posterior Tibial Load (PTL).Included articles in this graph: in vitro force in passive flexion [12, 13, 20, 62, 63, 86–89, 91], in situ force in passive flexion [9], modelling force in passive flexion [36, 75, 84], in vitro force with 100 N PTL [12, 13, 20, 86–88, 96, 97], in situ force with 100 N PTL [17] and in situ force with 134 N PTL [8, 15, 16, 18, 93–95, 98, 105].
Mentions: The majority of force data reported for the PCL during passive flexion has been acquired by the same research group using cadaveric knees and attaching a load cell to the isolated femoral attachment site of the ligament [12, 13, 20, 62, 63, 86–89]. In these studies, the knees were mounted in multi-degree of freedom jigs and manually moved through knee flexion. Based on their measurements, the PCL was found to be under low tension throughout flexion. The average tension in the PCL at full extension, 30° and 120° of flexion was approximately 15 (3), 4 (1) and 19 (5)N respectively (Fig 5). Smaller forces were reported by Wang and co-workers [91] who used a similar assessment technique, and were in a general agreement with a study using buckle force transducers implanted on the PM bundle [63]. Miyasaka and co-workers [62] detached the PCL from its femoral attachment site and reattached it to its anatomical position using a metal plate instrumented with 12 strain gauges. They reported only small forces in the PCL throughout the range of passive flexion with a maximum of 4 (1)N at 90°. In another study, a robotic manipulator together with a universal force sensor (UFS) was used to measure the in situ force of the PCL in nine cadaveric knees during passive flexion [9]. Except for 90° flexion, the force patterns of the PCL were close to the average force trend extracted from the data measured in vitro.

View Article: PubMed Central - PubMed

ABSTRACT

Background: The posterior cruciate ligament (PCL) is the strongest ligament of the knee, serving as one of the major passive stabilizers of the tibio-femoral joint. However, despite a number of experimental and modelling approaches to understand the kinematics and kinetics of the ligament, the normal loading conditions of the PCL and its functional bundles are still controversially discussed.

Objectives: This study aimed to generate science-based evidence for understanding the functional loading of the PCL, including the anterolateral and posteromedial bundles, in the healthy knee joint through systematic review and statistical analysis of the literature.

Data sources: MEDLINE, EMBASE and CENTRAL

Eligibility criteria for selecting studies: Databases were searched for articles containing any numerical strain or force data on the healthy PCL and its functional bundles. Studied activities were as follows: passive flexion, flexion under 100N and 134N posterior tibial load, walking, stair ascent and descent, body-weight squatting and forward lunge.

Method: Statistical analysis was performed on the reported load data, which was weighted according to the number of knees tested to extract average strain and force trends of the PCL and identify deviations from the norms.

Results: From the 3577 articles retrieved by the initial electronic search, only 66 met all inclusion criteria. The results obtained by aggregating data reported in the eligible studies indicate that the loading patterns of the PCL vary with activity type, knee flexion angle, but importantly also the technique used for assessment. Moreover, different fibres of the PCL exhibit different strain patterns during knee flexion, with higher strain magnitudes reported in the anterolateral bundle. While during passive flexion the posteromedial bundle is either lax or very slightly elongated, it experiences higher strain levels during forward lunge and has a synergetic relationship with the anterolateral bundle. The strain patterns obtained for virtual fibres that connect the origin and insertion of the bundles in a straight line show similar trends to those of the real bundles but with different magnitudes.

Conclusion: This review represents what is now the best available understanding of the biomechanics of the PCL, and may help to improve programs for injury prevention, diagnosis methods as well as reconstruction and rehabilitation techniques.

No MeSH data available.