Link between sporting knee injuries and total knee replacements
Currently there is a well-established association between knee injuries and the development of knee osteoarthritis (1). Although knee osteoarthritis and knee replacements are not the same thing – the two are heavily linked. For more information, have a read of my previous “Knee Osteoarthritis” blog which you can find HERE>>>. From this concept, it can be argued that if you were to have a knee injury, or multiple knee injuries – then you are more likely to develop osteoarthritis in the joint resulting in a requirement to have a knee replacement in the future (1).
What does the research say?
To investigate the legitimacy of this argument, researchers undertook a population-level study aimed to determine whether acquiring a knee injury would have health costs after 10-15 years (1). This study showed that if you were to suffer a knee injury from sport, than the likelihood of you having a knee replacement in the next 10-15 years doubles (1).
Similarly, a 2019 study looked at the relationship between specific knee injuries and the development of future knee osteoarthritis. These injuries were ACL tears, meniscal tears and a combination of the two (2). Interestingly, the study found that a meniscal tear, by itself or with an ACL injury is more of a risk factor than having an isolated ACL tear and reconstruction. However, the average age of ACL injuries in the study was 28-31 years old with the meniscal injury average age of 38. It is also important to note, that a degenerative tear of the meniscus (typically older populations) is more likely to develop OA post injury than a tear that is a result of trauma (typically younger populations)(2). The study concluded that if you were to injure your meniscus whether the ACL was affected or not, you are six times more likely to develop osteoarthritis in that knee compared to the uninjured knee (2). It also concluded that if you were to injure your ACL in isolation, than that knee is four times more likely to develop OA than your uninjured leg (2). These findings show that the function of your menisci play a significant role in the development, delay or prevention of knee osteoarthritis. They also highlight the importance of knee injury prevention programs and post-knee injury rehabilitation.
So what knee injury prevention program is best?
There is a significant amount of research that investigates what prevention programs are most effective at alleviating or reducing the risk of attaining a knee injury, particularly ACL injuries, during a sporting season. Most studies involve young female athletes in non-contact sports. Research shows that ideal prevention programs emphasise plyometric training (jumping/power drills), neuromuscular training and strength training with feedback on body biomechanics and landing technique (7). The literature recommends that the injury prevention program should last for 15-20 minutes in duration, completed 3 times a week and for a minimum of 6 weeks at the start of a season, or to be consistently used all season and perhaps replace the traditional warm-up (7). The core concepts of an effective knee injury prevention program are as follows:
1. Education and Feedback
Educational videos that address both safe and unsafe landing techniques should be used in conjunction with feedback regarding the individual’s landing technique. Time should also be delegated for the correction/practice of the correct biomechanics. Preventing the knee “falling in” (valgus) is critical, as well as “landing softly” with more weight on the forefoot (7). Use of mirrors and or video footage is useful.
2. Strength training
Strength training is crucial in the prevention of knee injuries. However, for efficiency, exercises should be body weight rather than requiring the whole team to use equipment or weights. I’ve included two example body weight exercises that target specific muscle groups that will help prevent a knee injury. Having strong hip abductors (gluteal muscles) may help reduce knee valgus, and hamstring strength is crucial to prevent quad-dominance (risk factor for ACL injuries). Single leg bridges are a great way to work on strengthening the posterior chain. If these are too difficult then the single leg bridge holds may be more effective.
Core strengthening is also recommended to stabilise trunk motion (another risk factor for knee injuries). The side plank is a great body weight exercise to address the core, and is recommended to be included in a knee injury prevention program.
High intensity agility drill involving both footwork and quick explosive movements. This allows power and speed with proper muscle recruitment. Some examples are cutting, jumping, lateral movements and “perturbations” such as cones or distractions in an attempt to resemble an in-game scenario (7).
Prevent Injury and Enhance Performance Program (PEP)
One example prevention program is the “Prevent Injury and Enhance Performance Program” or PEP. In a 2005 study, this program was implemented to 1041 female athletes playing club soccer, with 1905 athletes not using the program for comparison (7). Over the course of two seasons, only 6 athletes that were using the PEP suffered an ACL injury compared to 67 of those who weren’t using this program (7). Although the control group had twice as many athletes – the PEP had an 88% overall reduction in ACL injuries (7). This is consistent with another study that claimed prevention programs such as the PEP may significantly reduce the incidence of severe ACL injuries in female soccer players (3) Another study found that ACL/knee injury prevention programs were proven to reduce the amount of overall knee injuries; the studies involved in their meta-analysis did not find a significant reduction in ACL injuries specifically (3). This shows programs that may be implemented to prevent ACL injuries can also be effective at reducing the amount of other knee injuries such as a meniscal tear (2, 5).
As touched on in this blog, there are numerous events that are required to establish a link between sport and total knee replacements. Essentially it can be summarised as the following:
- Start a sport
- DON’T utilise a knee injury prevention program such as the PEP
- Gain a knee injury
- Develop osteoarthritis
- Get a knee replacement
From the steps above, and if we look at what the research tells us, it is clear that the most effective way to avoid a knee replacement that was initially caused by a sporting knee injury is to consistently complete a knee injury prevention program. The PEP has proved to be effective at this, however if the program used satisfies the correct criteria and is being completed at the recommended frequency – knee injuries (and ultimately knee replacements) can be avoided.
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- Ackerman, I. N., Bohensky, M. A., Kemp, J. L., & de Steiger, R. (2019). Likelihood of knee replacement surgery up to 15 years after sports injury: A population-level data linkage study.Journal of Science and Medicine in Sport, 22(6), 629-634. doi:10.1016/j.jsams.2018.12.010
- Grimm, N. L., Jacobs, J. C., Kim, J., Denney, B. S., & Shea, K. G. (2015). Anterior cruciate ligament and knee injury prevention programs for soccer players: A systematic review and meta-analysis. The American Journal of Sports Medicine, 43(8), 2049-2056. doi:10.1177/0363546514556737
- Mandelbaum, B. R., Silvers, H. J., Watanabe, D. S., Knarr, J. F., Thomas, S. D., Griffin, L. Y., . . . Garrett, W. (2005). Effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. The American Journal of Sports Medicine, 33(7), 1003-1010. doi:10.1177/0363546504272261
- Meyer, S. E., Yamato, T. P., & Saragiotto, B. T. (2017). Knee injury and ACL tear prevention programmes (PEDro synthesis). British Journal of Sports Medicine, 51(15), 1161-1162. doi:10.1136/bjsports-2016-097232
- Petersen, W., Stoffels, T., & Achtnich, A. (2018). Prevention of knee injuries and ACL ruptures systematic review and recommendations of the German knee society (DKG): The stop-X program. Orthopaedic Journal of Sports Medicine, 6(4), n.d. doi:10.1177/2325967118S00018
- Poulsen, E., Goncalves, G. H., Bricca, A., Roos, E. M., Thorlund, J. B., & Juhl, C. B. (2019). Knee osteoarthritis risk is increased 4-6 fold after knee injury – a systematic review and meta-analysis. British Journal of Sports Medicine, n.d. doi:10.1136/bjsports-2018-100022
- Voskanian, N. (2013). ACL injury prevention in female athletes: Review of the literature and practical considerations in implementing an ACL prevention program. Current Reviews in Musculoskeletal Medicine, 6(2), 158-163. doi:10.1007/s12178-013-9158-y