Influence of a mono-centric knee brace on the tension of the collateral ligaments in knee joints after sectioning of the anterior cruciate ligament--an in vitro study

Adaptation of Fibril-Reinforced Poroviscoelastic Properties in Rabbit Collateral Ligaments 8 Weeks After Anterior Cruciate Ligament Transection

Ligaments of the knee provide stability and prevent excessive motions of the joint. Rupture of the anterior cruciate ligament (ACL), a common sports injury, results in an altered loading environment for other tissues in the joint, likely leading to their mechanical adaptation. In the collateral ligaments, the patterns and mechanisms of biomechanical adaptation following ACL transection (ACLT) remain unknown. We aimed to characterize the adaptation of elastic and viscoelastic properties of the lateral and medial collateral ligaments eight weeks after ACLT. Unilateral ACLT was performed in six rabbits, and collateral ligaments were harvested from transected and contralateral knee joints after eight weeks, and from an intact control group (eight knees from four animals). The cross-sectional areas were measured with micro-computed tomography. Stepwise tensile stress-relaxation testing was conducted up to 6% final strain, and the elastic and viscoelastic properties were characterized with a fibril-reinforced poroviscoelastic material model. We found that the cross-sectional area of the collateral ligaments in the ACL transected knees increased, the nonlinear elastic collagen network modulus of the LCL decreased, and the amount of fast relaxation in the MCL decreased. Our results indicate that rupture of the ACL leads to an early adaptation of the elastic and viscoelastic properties of the collagen fibrillar network in the collateral ligaments. These adaptations may be important to consider when evaluating whole knee joint mechanics after ACL rupture, and the results aid in understanding the consequences of ACL rupture on other tissues.

Brace or no-brace after ACL graft? Four-year results of a prospective clinical trial

PURPOSE

A controversial discussion is held on using stabilizing knee braces after anterior cruciate ligament (ACL) surgery. The current study investigated the influence of a stabilizing knee brace on results after ACL reconstruction using patellar tendon autografts.

METHODS

A prospective randomized study was started including 64 patients divided into two equal groups and treated with or without a stabilizing knee brace for 6 weeks post-operatively. A follow-up examination 4 years after operation comprised IKDC 2000, KT1000 measurement, a visual analogue pain scale (VAS; scores 0-10) and radiographic evaluation. The t test for independent and paired samples and the Pearson's Chi-square test were used for statistical analysis (p < 0.05). The primary endpoint was the difference in IKDC classification.

RESULTS

Eighty-one per cent of the patients were examined 4 years post-operatively. IKDC 2000 subjective (brace group 90.5 ± 8.9, braceless group 93.2 ± 6.1) and objective results (brace A 30%, B 56%, C 16%; braceless A 32%, B 48%, C 20%) and instrumental measurement of anteroposterior laxity with KT1000 (brace 0.6 ± 2.4 mm, braceless 1.8 ± 3.4 mm) showed no significant differences. VAS pain results were significantly better in the braceless group at 1.0 ± 1.2 versus 1.9 ± 1.4 under sports activity or heavy physical work (p = 0.015). There were no radiographic differences concerning osteoarthritic findings and tunnel widening between the groups.

CONCLUSION

Post-operative treatment with a stabilizing knee brace after ACL replacement showed no advantage over treatment without a brace at 4-year follow-up. The use of a knee-stabilizing brace after isolated ACL reconstruction with autologous patellar tendon graft is not recommended.

LEVEL OF EVIDENCE

II.

Evaluation of the mechanical efficiency of knee braces based on computational modeling

Knee orthotic devices are commonly prescribed by physicians and medical practitioners for preventive or therapeutic purposes on account of their claimed effect: joint stabilisation and proprioceptive input. However, the force transfer mechanisms of these devices and their level of action remain controversial. The objectives of this work are to characterise the mechanical performance of conventional knee braces regarding their anti-drawer effect using a finite element model of a braced lower limb. A design of experiment approach was used to quantify meaningful mechanical parameters related to the efficiency and discomfort tolerance of braces. Results show that the best tradeoff between efficiency and discomfort tolerance is obtained by adjusting the brace length or the strap tightening. Thanks to this computational analysis, novel brace designs can be evaluated for an optimal mechanical efficiency and a better compliance of the patient with the treatment.

Current recommendations for anterior cruciate ligament bracing: when to use

Braces are often used during various stages of recovery from an anterior cruciate ligament tear despite there being sparse definitive research supporting their use. This article reviews the literature on brace use for patients with anterior cruciate ligament tears in order to provide a guide for clinicians. There is evidence to support immediate postoperative bracing, with the goals of maintaining full extension and decreasing effusion. There may be a psychological benefit for its use in return to sport; however, this should be weighed against decreased performance. In the context of modern graft-fixation techniques and early mobilization protocols, empiric functional brace prescription is not required for successful long-term clinical outcomes and return to sport.

Strategies to prevent injury in adolescent sport: a systematic review

This systematic review set out to identify randomised controlled trials and controlled intervention studies that evaluated the effectiveness of preventive strategies in adolescent sport and to draw conclusions on the strength of the evidence. A literature search in seven databases (Medline, SportDiscus, EMBASE, CINAHL, PEDro, Cochrane Review and DARE) was carried out using four keywords: adolescent, sport, injury and prevention (expanded to capture any relevant literature). Assessment of 154 papers found 12 studies eligible for inclusion. It can be concluded that injury prevention strategies that focus on preseason conditioning, functional training, education, balance and sport-specific skills, which should be continued throughout the sporting season, are effective. The evidence for the effectiveness of protective equipment in injury prevention is inconclusive and requires further assessment.