Return to sports after ACL reconstruction: a new functional test protocol

Abstract

Background: In literature, there are lack of studies proposing clear and rationally designed test battery to be performed after an ACL reconstruction.

Methods: From 2006 to 2015, 80 football players were subjected, after ACL reconstruction, to a newly conceived test battery analyzing: Isometric and isokinetic force productionThe different phases during the jumpThe correct control of the landing phase after jumpThe control of valgus during landing after jump and cutting movements.

Results: The isokinetic and isometric test do not show any significant relationship with the another test. The laboratory test as well the field test showed them a significant correlation.

Conclusions: The results showed that a normal force production during the laboratory does not guarantee an equally satisfactory production of force during the field test.

Study design: Case series (Level III).

Keywords: ACL; arthroscopic reconstruction; football; functional evaluation; rehabilitation.

Figure 1

During the IYYT the subject is bound to the equipment via the yo-yo cable which offers a supramaximal resistance making isometric the push movement. Two synchronized force platforms (Thesis System, Globus Italy. Reliability of the measure: 0.5 Kg; error of device: <1%; sample rate 1000 Hz; sample depth 140 bit) record the isometric strength value during the push performed by the subject.

Figure 2

The SPT protocol provides that the subject performs a CMJ (90° knee flexion angle) and stops the landing phase with a knee angle another time equal to 90°. Two synchronized force platforms (Thesis System, Globus Italy. Reliability of the measure: 0.5 Kg; error of device: <1%; sample rate 1000 Hz; sample depth 140 bit) record the force signal during the jump movement.

Figure 3

The negative acceleration peak (MA_neg) represents the overstretching capabilities of the extensor muscles. (^_ uninjured limb ^_ injured limb).

Figure 4

The maximum force applied during the negative phase (MF_ecc) represents the maximum negative strength expressed by the extensor muscles immediately before the inversion of the movement (i.e immediately before the positive phase) (^_ uninjured limb ^_ injured limb).

Figure 5

The MF_con value represents the capacity of storage and reuse of elastic energy by the extensors muscle-tendon unit (^_ uninjured limb ^_ injured limb).

Figure 6

The maximum impact force value during the landing phase (MFimp) highlights the protective mechanisms used by the subject (^_ uninjured limb ^_ injured limb).

Figure 7

Dynamic Q-angle measurement during MTLJT.

Figure 8

Dynamic Q-angle measurement during MSSCT.

Figure 9

IAT and IATm scheme. The test length – i.e the distance between the start point and the stop point – is, in both cases, 10 meters, while the width of the test area is 5 meters.