Return to Play After an Anterior Cruciate Ligament Injury: Prioritizing Neurological and Psychological Factors of the Decision-Making Algorithm

CENTRAL NERVOUS SYSTEM TREATMENT TECHNIQUES FOR THE SOCCER PLAYER

The ultimate goal is to create a foundational movement pattern that optimizes leverage and is protective of the ACL during decelerating, pivoting, and landing in a unipedal stance from a jump. The composite segments that are necessary to achieve this include local core stability to create lumbopelvic stiffness, and global core activation to enhance posterior chain stability. This should enable the player to feel more balanced when placing the pelvis in a more posterior and inferior position while still maintaining the trunk in a position that is parallel with the tibia, as the knee is flexed to an approximate 60° angle (Figure 1). From a frontal plane perspective, the acetabulum should bisect the malleoli of the stance leg, with a neutral tibiofemoral joint alignment (Figure 1).

The neuromotor training for the composite segments of this movement can begin in the “acute postoperative phase” (Table 1).   Because the surgical repair will limit the player’s capabilities in this stage, this is a good time to break down the foundational movement pattern into its component parts and ensure that the CNS receives a high number of quality repetitions of parts. In this phase, the player may begin an isolated training for the transversus abdominis, multifidus, and pubococcygeus. This can start in a supine position using biofeedback with an isometric contraction, progress to a standing position, and incorporate deep core activation with stance-phase gait training, mini squats, and lunge variations. This phase will require an abundance of visual and verbal feedback with an internal focus of control as the player gets used to activating the deep core and quad/hip synergy during functional lower extremity movements. Even in this early phase, the player should look to minimize anterior and/or posterior pelvic tilting and maintain a stiff thoracolumbar segment that remains parallel with the tibia during all functional movements.

Table 1. Adjunct CNS Treatment Principles for ACL Reconstruction in Soccer Athletes

Abbreviations: ACL, anterior cruciate ligament; CNS, central nervous system; CIMT, constraint-induced movement therapy.

As the player moves into the “subacute postoperative phase” (Table 1).   He or she will continue to use an internal focus of control to activate the local/global core synergy with functional movements progressing from double-leg, to single-leg positions. Partial practice, instead of whole practice, is still the predominant theme of the neural training process. In this phase, the knee and hip flexion angles can increase, and the player’s trunk and pelvic position should be critiqued in a single-leg position so that the trunk remains parallel with the tibia in the sagittal plane with a slight forward hip hinge. The pelvis should remain level throughout single-leg stance to ensure adequate activation of the lateral hip stabilizers. This is the stage where the player can learn to isolate closed kinetic chain hip rotation for pivoting, and so, single-leg hip internal and external rotation drills are useful, both with and without resistance. Skill acquisition is crucial in this phase because the patterns that the CNS adopts will form the foundation for more dynamic patterns that will occur in the later soccer-specific stages. Higher levels of cortical planning are still needed in this phase. For this reason, it is important that poor quality repetitions are recognized by the player and clinician so that he or she can learn to perform them correctly, albeit still with an internal focus of control. This is also a good time to begin to employ constraint-induced movement therapy as the player is able to replicate the desired pattern with more precision. For example, by eliminating the use of the upper extremities as a source of balance, the CNS is forced to program alternate synergies such as the lumbopelvic, and foot and ankle segments to maintain the desired alignment.

The “lower quarter static stability phase” (Table 1) marks a point where it may be useful to use direct strategies that have the capability to change CNS efferent owutput from a primary reliance on the visual processing areas in the posterior-inferior temporal gyrus back to the somatosensory area. It is critical that the player is able to make this transition in cortical reorganization and control, because ACL-injured subjects have been shown to have balance scores similar to healthy controls when they are able to use their vision, but this is reduced when vision is taken away.^99-105  Their balance will diminish even further if vision is modulated during more complex landing and pivoting maneuvers.^99-105 This may certainly explain why defending is a riskier task for ACL-injured players⁸⁹ as their visual system is focused more on tracking a player than attending to precision with movement planning.

To enhance this cortical reorganization within the context of soccer-specific movements, it is useful to start from a foundational single-leg position, with the knee approximating 60° of flexion and the trunk parallel to the tibia. In the frontal plane, the pelvis should be level, the trunk vertical, and the acetabulum bisecting the malleoli of the stance leg (Figure 1).   The player may initially work on getting into this foundational position with vision either partially obstructed using stroboscopic eyewear or completely obstructed if this equipment is unavailable.^106-108 The pattern can be progressed by constraining the upper extremities to force reliance on the lumbopelvic and foot/ankle strategies for balance. Head and/or trunk turns can be added to simulate the external focus of control that is required with movement in soccer. These should progress from slow to fast and anticipated to unanticipated as the player demonstrates competence in maintaining stability at each segment within the foundational stance position. Once this is in play, a ball should be introduced into the drills. As the player maintains the foundational position with vision diminished and upper extremities constrained, they should attempt to reach for or trap a ball from this position. If vision is completely obstructed, then the player can be instructed to open his/her eyes just as the ball arrives to induce a reactive response. Again, quality repetitions are essential for learning to occur, and subsequent skill acquisition to take place in the CNS; thus, close scrutiny should be paid to the qualitative essence of the movement patterns to ensure pristine biomechanics during this phase.

The “lower quarter dynamic stability phase” (Table 1) should continue with the same neuromotor training principles employed in the previous phase, except that the drills will now involve plyometrics. The player should ultimately progress from double-leg, to single-leg jumps and then linear to diagonal. Vision should still be obstructed and upper extremities constrained to channel the lumbopelvic region for force production and balance. Movement quality in the foundational position remains paramount with these drills to ensure that skill acquisition is occurring and injury risk is being mitigated. An external focus of control can be introduced by applying an unanticipated perturbation during a jump. Additional learning opportunities should include unanticipated head and trunk turns while landing in a unipedal stance from a jump. The task can be made more specific by having the player trap a pass while doing linear or diagonal single-leg hop progressions. In this manner, the player’s CNS can become reorganized to program the requisite synergies to maintain a protective foundational position on the stance leg, as the contralateral limb is required to perform work that is far outside the player’s base of support.

Continue to: The final segment of the CNS neuromotor rehabilitation program...