Surgery is only the first step

In orthopedics, cruciate ligament ruptures and ligament reconstructions are part of everyday clinical routine. This is usually followed by an intensive rehabilitation phase to prevent functional impairment and to decrease risk of osteoarthritis of the knee. Here, the GenuTrain support belongs in the toolbox for clinicians and physical therapists. Its acute and medium-term effects on patients have now been investigated in a current study. Bauerfeind life talked to the study director, Professor Dr. Gisela Sole, and Professor Dr. Niels Hammer, an expert in anatomy and co-author of the study.

“Rugby is very popular here in New Zealand,” explains Professor Dr. Gisela Sole from the University of Otago, Dunedin, “it’s a very physical sport, involving abrupt changes of direction. I’m sure this sport contributes to the high number of cruciate ligament ruptures in men and women, and in netball [editors’ note: a variant of basketball].” With an incidence of 58 per 100,000 inhabitants, New Zealand also ranks among the top when comparing worldwide numbers of ACL repairs. The population’s sporty lifestyle is a blessing and a curse. “In fact, the age range in which people are affected by torn cruciate ligaments is decreasing. We’re now seeing patients as young as 12 or 13 years of age,” reports Professor Dr. Gisela Sole, who is associate professor for physiotherapy and a well-known researcher for rehabilitation and outcomes of knee injuries. But anterior cruciate ligament tears are also very common in the northern hemisphere as well. They are rarely caused by wear and tear, but most often by trauma, for example, during team sports or skiing. This, in turn, leads to high numbers in cruciate ligament reconstruction surgery.

For the subsequent physiotherapeutic treatment, every measure that safely restores the patient’s knee-related performance is of value after a cruciate ligament tear to ensure they can return to everyday activities and sports as soon as possible. A knee support like the GenuTrain can be used as adjunct to rehabilitative exercises, based on its stabilizing and pain-relieving effects, way beyond its post-operative application. But can we actually measure the effect of supports? This question was addressed by the study director, Professor Dr. Gisela Sole, and Professor Dr. Niels Hammer (see below) in a Bauerfeind-sponsored studies at the Centre for Health, Activity and Rehabilitation Research at the University of Otago’s School of Physiotherapy.

Proof of significant effects

The research project investigated the immediate and six-week effect of wearing the GenuTrain support in patients with chronic instability following cruciate ligament surgery. The patients (who had undergone surgery at least six months ago, but not longer than five years ago) were examined in a randomized cross-over laboratory trial to measure the acute effect. For the evaluation of the six-week effect, the patients were allocated either to an intervention group (support wearing time of at least one hour daily) or a control group (no support). The first test already showed a significant effect of the GenuTrain. In the horizontal single-leg hop, the distance improved by five centimeters (3.6 percent) in the full set of patients who wore a support. This also proved to be a sustained effect: the “supports group” was able to maintain this improved outcome after six weeks. The subjects were also assessed using the IKDC-SKF (International Knee Documentation Committee/Subjective Knee Form) questionnaire. This self-rated questionnaire comprises 18 questions related to knee symptoms and function on a scale from 1 to 100 (higher scores indicate lower levels of symptoms and higher levels of function). The analysis of these questionnaires demonstrated that patients who wore a support were noticeably less likely to experience knee dysfunction like “locking” or “catching.” These results have already been published. Further publications by Gisela Sole and Niels Hammer that investigate the biomechanics of the surgically treated knee using a step-down hop are about to follow and will be available online soon.

Professor Dr. Gisela Sole explains why the findings are relevant for working with patients: “We conclude that it may be appropriate to recommend the use of knee supports in physiotherapeutic practice for patients who undergo training including horizontal jumps or similar exercises. We know that the most important part of recovery is training – and the fact that this may be promoted by a support speaks in favor of the device.” And when asked about the mechanisms behind this effect, she replied: “We cannot say for sure. But it’s very likely that the feeling on the skin and the gentle compression around the knee increase the patient’s perception of their knee. This perception makes patients feel secure, which, in turn, probably makes them achieve a slightly greater jumping distance. What I found interesting was that the subjects in our study who wore a support also showed higher overall levels of physical activity compared to the control group. It could mean that the support encouraged them to be more confident, without the constant fear of re-rupturing.”

Securing the treatment outcome over the long-term

The burden imposed by cruciate ligament ruptures and relevant treatment regimes is not insignificant – neither for the individual patient nor for the healthcare system as a whole. “ACL tears might be less common than injuries to the Achilles tendon, but the cost is higher since it involves higher levels of disability and more expensive rehabilitation measures and potential surgery.” When evaluating the success of treatment, however, medium and long-term assessments are crucial. After all, both instability and functional impairment of the knee as well as gonarthrosis potentially developing over time should be the focus of any treatment regimen following ligament reconstruction. “There is no evidence indicating reconstruction reduces the risk of developing osteoarthritis, and osteoarthritis is one of the most concerning risks for the following ten to 15 years. That is the reason why really anything is of value that can secure the outcome,” Professor Dr. Gisela Sole emphasizes.

“In terms of rehabilitation, it is neuromuscular control that needs to be improved, because cruciate ligament reconstruction does not repair the ligament’s neurophysiology, meaning proprioception. That is why rehabilitation is crucial for securing the surgical outcome long-term.” The GenuTrain is a support that stimulates proprioception, thus supporting the link between anatomy and function. “We need strategies to maintain long-term physical activity and muscle strength. After all, I’m sure about one thing,” Professor Dr. Gisela Sole warns, “and that is that people who had cruciate ligament reconstruction will definitely need rehabilitative maintenance strategies – for the rest of their lives.”

Overview of the study

Part 1: Acute effect > randomized cross-design
Part 2: Six-week effect > controlled clinical study with a supports group and a control group

Sample size: 34 subjects (18 males, 16 females)
Inclusion criteria: Previous cruciate ligament reconstruction surgery within 6 months to 5 years, presenting with functional deficits in the knee (between 40 and 80 of a max. of 100 points on the IKDC-SKF score)

Test method and measurements: Horizontal hop, single-leg jump from standing on one leg and landing on one leg, average of three attempts, injured side without and with the support; LSI (Lateral Symmetry Index); IKDC-SKF score

Study results were published open access in the peer reviewed journals BMC Musculoskeletal Disorders und PLOS One: 

Sole, G., Lamb, P., Pataky, T. et al. Immediate and 6-week effects of wearing a knee sleeve following anterior cruciate ligament reconstruction: a cross-over laboratory and randomised clinical trial. BMC Musculoskelet Disord 22, 655 (2021). https://doi.org/10.1186/s12891-021-04540-x

Sole, G., Lamb, P., Pataky, T. et al. Immediate and six-week effects of wearing a knee sleeve following anterior cruciate ligament reconstruction on knee kinematics and kinetics: a cross-over laboratory and randomised clinical trial. BMC Musculoskelet Disord 23, 560 (2022). https://doi.org/10.1186/s12891-022-05488-2

Sole G., Pataky T., Hammer N., Lamb P. Can a knee sleeve influence ground reaction forces and knee joint power during a step-down hop in participants following anterior cruciate ligament reconstruction? A secondary analysis. PLOS ONE 17(12) (2022): e0272677. https://doi.org/10.1371/journal.pone.0272677

Find out more: The three hierarchical levels of functional recovery

Professor Dr. Niels Hammer is professor and chair of the Division of Macroscopic and Clinical Anatomy at the Medical University of Graz, Austria, since October 2019. Between 2015 and 2019, he was professor for Clinical Anatomy at the University of Otago, where he set up the first integrated laboratory for anatomy and biomechanics in Australasia. He has collaborated with Professor Dr. Gisela Sole in the study investigating the effectiveness of knee supports and other projects in musculoskeletal research.

life: As an expert in anatomy, you have a keen eye for the interrelations that can be found in the knee. What happens during recovery over time?

Prof. Dr. Niels Hammer: There appears to be a hierarchy of healing, so to speak, consisting of three levels to restore function. When somebody tears an anterior cruciate ligament, the first level is about restoring the anatomical structures. This is followed by regaining muscle strength. The third level is neuromuscular control – an aspect that has a lot to do with proprioception.

Does a stabilizing support act as an overarching aid that can help during the entire process?

Prof. Dr. Niels Hammer: There is no conclusive evidence proving that knee sleeves influence muscle strength or anatomical alignment. But there seems to be a clear link between the topmost level I mentioned, comprising neuromuscular control and how it is integrated into anatomical and muscular conditions. What matters most for patients is that they may use the reconstructed knee with confidence and with less concern about repeated injuries at that stage of their rehabilitation process.

Are there any differences when treating cruciate ligament ruptures between New Zealand and German-speaking countries?

Prof. Dr. Niels Hammer: Yes, actually, there is marked difference. In New Zealand, a relatively high number of surgical repairs is performed when compared to the German-­speaking countries. Also the underlying surgical treatment differs. In Europe, surgeons often only choose from two or three options, mainly in terms of the material used as an implant. New Zealand has greater variety for this procedure and less strict guidelines for selecting the type of surgical reconstruction.

GenuTrain: Stabilization and pain reduction

Activity promotes recovery: The GenuTrain knee support exerts compression, thus reducing knee pain in cases of post-traumatic or post-operative irritation, arthritis, osteoarthritic changes and tendomyopathy. Thanks to the highly textured knitted fabric and viscoelastic pad, the textile’s intermittent compression massage promotes circulation during movement and helps activate the stabilizing joint muscles. The support features an integrated Omega+ Pad to protect the kneecap and reinforce proprioceptive stimulation based on pressure points and massage nubs made of firmer material. The knitted fabric is slightly softer and more breathable at the back of the knee for enhanced wearing comfort during everyday activities.

Get the white paper

Selected results of the study are summarized in the white paper “Effectiveness and Long-Term Effect of a Knee Support in Patients with Chronic Instability Following ACL Recon­struction”. This paper is available as a PDF file in English or German. To get a free copy simply send a brief email to medical.affairs@bauerfeind.com.

Images: istockphoto.com/Anut21ng, University of Otago, Bauerfeind, privat