Characterisation of in-vivo mechanical action of knee braces regarding their anti-drawer effect

Effect of Different Knee Braces in ACL-Deficient Patients

Knee braces are often used during rehabilitation after ACL injury. There are two main concepts, rigid and soft braces, but studies comparing the two show conflicting results. Most studies used movement tasks with low translational or rotational loads and did not provide joint kinematics. Therefore, the purpose of this study was to investigate the influence of two different knee braces (rigid vs. soft) on knee joint kinematics in ACL-deficient patients compared to an unbraced control condition using two tasks (walking and 180° cutting) provoking knee movements in the frontal and transverse planes. 17 subjects with ACL-deficient knees participated in this study. 3D knee joint kinematics were recorded. To provoke frontal plane knee joint motion a laterally tilting plate was applied during a walking task. Both braces reduced the maximum valgus angle compared to the unbraced condition, stabilizing the knee joint against excessive valgus motion. Yet, no differences in peak abduction angle between the two braces were found. However, a significant extension deficit was observed with the rigid brace. Moreover, both braces increased transverse plane RoM and peak internal rotation angle, with the effects being significantly larger with the rigid brace. These effects have been associated with decreased knee stability and unphysiological cartilage loading. Therefore, the soft brace seems to be able to limit peak abduction with a lesser impact on physiological gait compared to the rigid brace. The cutting task was selected to provoke transverse plane knee movement and large external knee rotation was expected. However, none of the braces was able to reduce peak external knee rotation. Again, an increase in transverse plane RoM was observed with both braces. Based on these results, no brace outmatched the other in the second task. This study was the first attempt to clarify the effect of brace design for the stabilization of the knee joint during movements with frontal and transverse plane loading. However, to provide physicians and patients with a comprehensive guideline for brace usage, future studies will have to extent these findings to other daily or sportive movement tasks.

Custom-made hinged knee braces with extension support can improve dynamic balance

Background/Objective: We investigated whether custom-made hinged knee braces can facilitate knee extensor and flexor strength and influence functional performance as compared with other knee braces.

Methods

We enrolled 28 healthy young participants with no history of physical activity or brace use. The participants executed functional performance tests under the following 5 conditions: 1) without a knee brace, 2) wearing a knee sleeve, 3) wearing a hinged knee brace without assistance, 4) wearing a knee brace with extension support (KBE), and 5) wearing a knee brace with flexion support (KBF). The KBE and KBF were custom-made hinged knee braces equipped with rubber tubes. The functional performance tests performed assessed maximal isokinetic strength, single-leg jumping height/distance, anterior and posterior reach distance on a single leg, and dynamic balance ability.

Results

The benefit of the custom-made hinged knee brace was observed only during the anterior reach distance on a single leg. The KBE allowed a significantly greater single-leg anterior reach distance when compared to that in the no brace condition. There was a significant relationship between the improvement in the single leg anterior reach distance with KBE and the changes in isokinetic knee extension with KBE compared to the no brace condition. With regard to other parameters, there were no differences compared with the use of other knee braces and thus no apparent benefit.

Conclusion

Our findings suggest that using a KBE enhances performance during dynamic balance activity in individuals who benefit from improved knee extension strength.

Prospective comparative study of knee laxity with four different methods in anterior cruciate ligament tears

BACKGROUND AND PURPOSE

Anterior knee laxity can be evaluated using different devices, the most commonly used being the Telos®, KT1000®, Rolimeter®, and GNRB®. However, the laxity values obtained with these devices have never been compared to one another. As such, the outcomes of studies using these different knee laxity measurement devices may not be comparable. The primary purpose of this study was to determine the side-to-side laxity difference in patients with one ACL-injured knee, using each of these devices, and to compare the values obtained from each. We hypothesized that the measurements of laxity would vary depending on the device used.

METHODS

This was a prospective study. All patients with an ACL injury, in which surgical reconstruction was planned, underwent pre-operative knee laxity measurements using four different devices. The concordance correlation coefficient (CCC) of the results was compared between the four devices.

RESULTS

The study enrolled 52 patients. With regard to the values of the side-to-side differences, the KT1000® and the GNRB® obtained the most similar values (CCC = 0.51, 95% CI 0.37-0.63). The two devices with the lowest correlation were the Telos® and the Rolimeter® (CCC = 0.04, 95% CI - 0.14-0.23). The comparability was considered average for the KT1000® and GNRB® and poor for the other devices.

CONCLUSIONS

The knee laxity devices used in regular practice are not comparable to one another. As a result, caution must be taken when comparing results from studies using these different devices.

Anterior cruciate ligament reconstruction, rehabilitation, and return to play: 2015 update

Anatomical discoveries and a growing appreciation of the knee as a complex organ are driving innovations in patient care decision-making following anterior cruciate ligament (ACL) injury. Surgeons are increasing their efforts to restore combined mechanical-neurosensory ACL function and placing more consideration on when to reconstruct versus repair native anatomical structures. Surgical options now include primary repair with or without reinforcing the injured ACL with suture-based internal bracing, and growing evidence supports biological augmentation using platelet-rich plasma and mesenchymal stem cells to enhance tissue healing. Physical therapists and athletic trainers are increasing their efforts to facilitate greater athlete cognitive engagement during therapeutic exercise performance to better restore nonimpaired neuromuscular control activation amplitude and timing. Knee brace design and use needs to evolve to better match these innovations and their influence on the rehabilitation plan timetable. There is a growing appreciation for the multifaceted characteristics of the rehabilitation process and how they influence neuromuscular, educational, and psychobehavioral treatment goal achievement. Multiple sources may influence the athlete during the return to sports process and clinical outcome measures need to be refined to better evaluate these influences. This update summarizes contemporary ACL surgical, medical, and rehabilitation interventions and future trends.