Sports Medicine Research: In the Lab & In the Field: Knee Injuries and Knee Osteoarthritis: A Meta-analysis (Sports Med Res)
Tuesday, October 18, 2011

Knee Injuries and Knee Osteoarthritis: A Meta-analysis

History of knee injuries and knee osteoarthritis: a meta-analysis of observational studies

Muthuri SG, McWilliams DF, Doherty M, Zhang W. OA Cartilage. 2011. 19(11):1286-93.

It has been suggested for years that knee injuries are a risk factor for developing knee osteoarthritis (OA). Unfortunately, most studies are inconsistent in how previous knee injuries are defined (e.g., type of injury, severity of injury) and this has made it challenging to accurately determine the true risk of developing knee OA after sustaining an injury. Therefore, Muthuri et al performed a meta-analysis of 24 observational studies to quantify the association between knee OA and history of knee injury. Unfortunately, 14 (58%) of the studies did not provide a detailed definition of knee injuries. Most studies relied on participants reporting a history of injury but 3 studies verified a knee injury with magnetic resonance (MR) imaging or hospital records. Overall, participants with a history of knee injury were 4.2 times more likely to have knee OA. Men and women with a history of knee injuries were 5.8 and 2.6 times more likely to have knee OA, respectively, than members of the same sex with no history of knee injury. Furthermore, the odds for knee OA among males with a history of knee injury (compared to those without a history of knee injury) were higher than the odds among females with a history of knee injuries (compared to those without a history of knee injury). Unfortunately, not enough studies specified the site or severity of injury to determine how these variables influence the odds of developing OA. There is some evidence that the type and severity of injury may be important. For example, four studies that defined injuries based on MR imaging of meniscal damage or self-reported meniscectomy showed a high risk of developing OA (odds ratio = 6.9; significantly above the overall odds for knee OA reported earlier).

This study is significant because it verifies that knee injuries are a risk factor for developing knee OA and it highlights some key questions that need to be answered. Interestingly, gender may be an influential factor in predicting the risk of knee OA among individuals with a history of knee injury but is unclear if it is a factor causing the greater risk among males or an indirect assessment of other physical or psychosocial variables. Future research will need to determine if injury type and severity as well as gender are key determinates for the risk of developing knee OA. Furthermore, it is important to clarify if injuries early in life increase the risk of developing knee OA more than injuries later in life. It would also be interesting to see how follow-up time influenced the results because longer follow-up after injuries may provide more time for OA to be detected. Ideally, some of these questions should be addressed in prospective studies that would allow us to accurately record the type and severity of injury, confirm that absence of OA at the time of injury, and the time it takes for OA to be detected. Several studies are currently monitoring patients with anterior cruciate ligament injuries but it will also be important to monitor healthy athletic controls change over time. In the meantime, this study demonstrates that a history of knee injury is a strong risk factor for the development of knee OA and as the authors note “knee injuries may be prevented…which implies that more initiatives aimed at reducing injuries…could be beneficial in reducing the risk of future knee OA.” This study highlights the need for more research from the sports medicine community as well as the importance for us to further develop and implement injury prevention programs. Has your clinical site started to use injury prevention programs?

Written by: Jeffrey Driban
Reviewed by: Stephen Thomas

Related Posts:

Muthuri SG, McWilliams DF, Doherty M, & Zhang W (2011). History of knee injuries and knee osteoarthritis: a meta-analysis of observational studies. Osteoarthritis and Cartilage, 19 (11), 1286-93 PMID: 21884811


Timothy said...

During my internship, a football athlete suffered a tibial plateau fracture with PCL tear. As a result of this, the 20 year old athlete developed OA by the 6 month mark.

Jeffrey B. Driban, PhD, ATC, CSCS said...

Hi Timothy: That's a good point that intra-articular fractures seem to be strong risk factors for OA. This meta-analysis found it challenging to determine the true risk associated with specific injuries. Bruce Beynnon presented a few years ago at the NATA Annual Meeting that the severity of the initial injury may be an important factor influencing the risk of developing OA. The greater injury severity may be related to greater inflammation and biomechanical changes to the joint. There is some good animal evidence to suggest that the greater the injury severity the quicker the joint reaches end-stage OA. Intra-articular fractures would definitely represent a severe injury especially since it disrupts homeostasis in various tissues in the joint and can dramatically influence joint loading. Thanks for the comment!

Greg said...

I have an athlete that I have been working with for nearly 4 months now. She has a history of 2 lateral meniscectomy's and most recently a lateral meniscus repair, 6 months ago. When the doc went in to preform her surgery he noted the the development of OA and degeneration already present throughout her knee.
She participates fully in her sport but has lingering swelling and lacks full extension. Treatments primarily focus on the swelling and ROM right now to control her symptoms during her intense, short season. There are certainly aspects of her biomechanics that can be improved upon but it is difficult to rationalize increasing demands on an already swollen knee in the middle of the season. Our plan is during the off-season to focus on regaining full ROM and improving her biomechanics. Part of me wonders though if lacking full extension could be a protective? Extension and rotation has been the mechanism of injury each time. She has 2 more years of collegiate participation and is a high level athlete. Are there any suggestions that you have to prevent further injury?
It would be interesting to see if individuals with damage to the lateral meniscus are as likely to develop OA as those with medial meniscus injuries. Also, for those individuals who have been diagnosed with a meniscus tear who have very minor symptoms is it appropriate to operate on them (regardless of the chance of healing)? Would those individuals show the same amount of degeneration as those who had undergone a meniscectomy or meniscus repair?

Jeffrey B. Driban, PhD, ATC, CSCS said...

Hi Greg: Interesting case and some very good questions. I'll try to address what I can and hopefully others will chime in.

You bring up a good point about the interconnection between meniscal pathology, knee extension (or knee kinematics in general), and effusion (and I would add inflammation).

There have been studies, for example Frank Roemer et al (2009;, that demonstrated that knees without OA but with meniscal pathology (medial or lateral) are more likely to have effusion. Furthermore, the effusion can lead to arthrogenic muscle inhibition of the quadriceps (for example, see Riann Palmieri-Smith et al, 2007, Palmieri-Smith et al demonstrated that a simulated effusion may lead to quadriceps muscle inhibition and increase loading to the knee…potentially exposing the joint a higher risk of injury or at least greater risk for developing joint degeneration. The lack of extension I believe can also increase the loading on the patellofemoral joint and alter the loading to the tibiofemoral joint which could probably lead to effusion and overloading to regions not used to those higher loads. You can see how the initial meniscal tear started (or further propagated) the knee on a vicious cycle. Ideally we would like to stop that cycle or slow it down.

Regarding lateral meniscal tears:
Martin Englund et al (2010; and Grace Lo et al ( ) showed that in knees with osteoarthritis medial and lateral meniscal tears are associated with lesions in the bone that are common in osteoarthritis. These lesions have been associated with symptoms and further joint degeneration. Another article by Englund et al suggested that medial and lateral meniscectomy had similar associations on osteoarthritis radiographic and symptoms outcomes (

23% of people 50 to 90 years of age with no evidence of radiographic OA and no knee symptoms have at least one meniscal tear. Among people with no knee symptoms but have radiographic signs of joint degeneration ~60% of them will have some meniscal pathology (Englund et al So there are definitely a good number of people walking around with meniscal tears and no symptoms. Some have hypothesized that meniscal pathology, even when asymptomatic, may be one of the first degenerative changes towards osteoarthritis (it seems to be a strong risk factor for osteoarthritis). There have also been some studies that suggest that the type of meniscal tear might be an important factor influencing joint loads (see Muriuki et al (2011; as an example). These findings may help clarify which types of tears should be repaired and which tears can remain as is (maybe). We actually need a lot more data to determine if meniscal repairs are protecting the joint over time.

I hope this helps with some of your questions I hope that we hear from some of the other people on the site that might have some insights.

Nicole Cattano said...

Similar to the others that have posted. I have had quite a few athletes that have suffered from early onset OA after meniscus injury. In the last 5 years, that has been 3 people. For 2 of them, the physician has prescribed and fitted the athletes with a ROM restriction brace. One was restricted from the last 7 degrees of extension, and the other was restricted to not passing 100 degrees of flexion. One successfully completed the remaining 2 years of their college basketball career. The other is 2 years into trying to successfully complete the remaining 3 years of their collegiate basketball career. (SO I can let you know after this year how successful it is).

Greg-maybe you could talk to your team physician about the possibility of a ROM restricting brace for your athlete? You may be right that the lack of full extension could be protective in nature. The medial vs. lateral meniscus is interesting too. And I am not sure of the answer. However, anecdotally I have had 5 lateral and 3 medial in the last 10 years that have resulted in early onset OA-not sure if that means anything!

Mark A. Rice said...

I wonder if there is any benefit to wearing an unloader brace post meniscal injury/surgery in effort to stay ahead of OA/DJD. They're typically ordered for people with more advanced DJD, but it might not be a bad option for a younger patient especially if OA is clearly an issue.

Jeffrey B. Driban, PhD, ATC, CSCS said...

Mark that makes sense. Those braces are notoriously hard to wear properly but several companies are exploring newer versions that stay in place better and are more comfortable.

Nicole Cattano said...

Mark-that would be a great idea. There is a ton of literature to support a softening of the articular cartilage post-injury, that once a compressive/shear load is added can negatively affect the cartilage or accelerate what is already degrading there. I would be interested to see the results of that! It may give the injured cartilage time to recover prior to loading again.

Eunwook said...

I think once joint started to degenerate for any reason, it is not easy to stop and to delay the onset of osteoarthritis. Bring the knee function back to previous injured level would be the most significant to prevent further knee joint injury. Restore full range of motion, full quadriceps and hamstring strengthening, and no compensating lower extremity biomechanics would be involved in the normal knee function. One of the important things in order to reduce further joint damage is to reduce compressive load on the joint surface. I usually focus on maintaining optimal body weight after lower extremity injury because to gain weight after injury would affect negatively on the knee joint and it increases joint compressive loading. Sometimes changing life style (changing types of exercise) would be the prevention strategy to prevent further joint damage.

Jeffrey B. Driban, PhD, ATC, CSCS said...

Eunwook: You bring up a great point. Once a person injures their joint and increases their risk of OA it is critical for them to maintain a healthy lifestyle. They should properly rehab, exercise, and maintain a healthy body weight. It will be interesting to see research to verify if this strategy will truly reduce the risk later in life.

Nicole Cattano said...

Jeff and Eunwook bring up great points. I wonder if outcomes would be different if the focus was shifted to restoring normal biomechanics/strength as opposed to return to activity beng our main goal? The struggle remains with the identity of our role as our role to returns athletes to sport, or to return normal function and promote long-term health? I think oftentimes it is easy to become near-sighted and focus on the short-term goal of returning to sport, without regard to long-term health consequences.

Jeffrey B. Driban, PhD, ATC, CSCS said...

Nicole: I think one of the main questions that came out of the NATA Free Communication Session in June regarding post-traumatic changes is whether or not the joint ever returns to normal biomechanics, strength, and biochemistry. We need more research in that area. We need to have a better understanding of how these things are changing over time after an injury. That may then help us figure out when is the optimal time for return to play and what can we do to ameliorate the risk to the joint.

I agree we, clinicians in sports med, can often become near-sighted. We need to be the voice of reason sometimes about balancing short-term gains and long-term health. In sports medicine, we often specialize in prevention but we need to remember prevention includes acute and chronic conditions.

DePuy Pinnacle Lawsuit said...

True, several studies has shown that hip and knee injury may cause hip pains that may lead to osteoarthritis and there is a need to see a doctor on this.

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