The 7 most common causes of cruciate ligament reconstruction failure

The causes for an unsatisfactory result after cruciate ligament reconstruction can be complex and multifactorial, we have summarized the 7 most common causes for the failure of cruciate ligament reconstruction.

1. new trauma

Traumatic ACL reconstruction failure can be divided into early failure - before graft healing and postoperative rehabilitation is complete, and late failure - after resumption of daily activities and sports. The causes are usually too aggressive, stressful rehabilitation, too early resumption of sports activities and insufficient neuromuscular control, especially before complete graft healing. Late ligamentoplasty failure can occur at any time even with a perfect surgical result due to adequate trauma. A rerupture rate of 5-10% is assumed for an athletically active patient population.

2. accompanying instabilities

ACL ruptures often occur in combination with additional injuries to other structures of the knee joint (medial ligament, ALL complex, etc.). Since the medial ligament, for example, has a very good healing tendency, medial ligament injuries in combination with anterior cruciate ligament ruptures usually heal without complications. However, especially medial ligament injuries with a lower leg tear (Stener-like lesion) and upper leg grade II and III injuries should be treated surgically; conservative healing is often insufficient for these injuries. However, injuries to the anterior cruciate ligament with the ALL complex (anterolateral ligament) are often overlooked. These combined knee instabilities may be a reason for failure after cruciate ligament reconstruction.

3. biological failure

In patients without evidence of surgical error or retrauma, "biological failure" may be the reason for failed ACL reconstruction. By the term "biological failure" we understand e.g. graft-inherent causes, such as insufficient healing or insufficient remodeling process of the tendon graft. Various biological and biomechanical factors in the course of this remodeling process and the healing phase can lead to the failure to create a functional new ACL. Reasons for a delayed healing phase are e.g. a disturbed revascularization with reduced cell infiltration into the graft, the associated reduced supply of growth factors delays or prevents the remodeling and healing process of the graft and thus increases the susceptibility to graft failure.

4. rehabilitation error

Anterior cruciate ligament reconstruction (ACL plastic) is an established treatment after an anterior cruciate ligament injury. In addition to its mechanical function in maintaining knee stability, the anterior cruciate ligament contains so-called mechanoreceptors and therefore directly affects the neuromuscular control of the knee joint. The changes in the motor control level may therefore be accompanied by loss of coordination, postural control (trunk stability), muscle strength and movement patterns. Therefore, the training concept should include criterion-guided rehabilitation in addition to temporal guidelines. This makes anterior cruciate ligament rehab more individualized than conventional physical therapy programs. Especially in adolescent athletes, who often re-enter sport-specific loading too early, this approach is crucial to avoid re-rupture of the plastic.

"An ACL injury can therefore be considered a neurophysiologic dysfunction rather than a simple ligamentous injury"

5. tunnel widening

In orthopedic surgery, "tunnel widening" refers to a phenomenon that can lead to instability of the knee joint after reconstruction of a torn cruciate ligament (cruciate ligament tear). "Tunnel widening" causes a widening of the drill channel in which the cruciate ligamentoplasty graft is located. Bore channel widening can have multiple mechanical but also biological causes. A clear separation is difficult, since mechanical stimuli always lead to biological changes and vice versa. Relative movements between the graft and the drill channel in which the graft is located can lead to widening of the drill channel, e.g. the use of a bioabsorbable screw is associated with greater widening of the lower leg tunnel than the surgical technique (all-inside) with button fixation.

6. leg axis error/ slope value

In revision surgery of failed anterior cruciate ligament recon struction, leg axis determination with evaluation of the sagittal inclination of the lower leg (slope) has considerable clinical relevance for the stability of the knee joint. In case of clinical suspicion of a malposition of the leg axis ("bow-leg-x-leg"), radiographic whole-leg stance imaging with evaluation of the slope value is also essential in our diagnostic concept before revision with cruciate ligament replacement.

"An increased slope (' 12mm ) of the lower leg may be the cause of recurrent instability".

7. drilling channel localization

The anatomical drill channel placement is probably the most significant factor for a satisfactory result after anterior cruciate ligament replacement. The goal of drill canal placement is primarily to restore stability of the knee joint with unrestricted mobility of the operated knee joint in reference to the healthy knee joint. Three examples will be used to demonstrate the most common non-anatomic drill channel placements and their effect on mobility and stability after cruciate ligament surgery:

More info: Drill channel positions of cruciate ligamentoplasty