Statistics on Knee Pain by Age Group

July 4, 2024

Decoding statistics on knee pain by age group: explore causes, treatments, and the impact on quality of life.

Here are the top 10 statistics on knee pain by age group:

Approximately 18% of people aged 18-44 experience knee pain.
The prevalence of knee pain increases to 23% for those aged 45-64.
Among adults 65 and older, nearly 37% report experiencing knee pain.
Knee pain is more common in women than men, with a prevalence of 23% compared to 18%.
The lifetime risk of developing symptomatic knee osteoarthritis is about 45%, with the risk increasing with age.
Around 80% of people with osteoarthritis have some degree of movement limitation due to knee pain.
Knee pain is a leading cause of disability among older adults, affecting more than 25% of those over 55.
The prevalence of knee pain has increased by approximately 65% over the past 20 years, largely due to an aging population and rising obesity rates.
Nearly half of all adults will develop symptomatic knee osteoarthritis by age 85.
Knee pain accounts for approximately one-third of all doctor visits for muscle and bone pain in the U.S.

Prevalence of Knee Pain

Knee pain is a common health complaint that affects individuals of all ages. Various factors contribute to the prevalence of knee pain, including age, weight, and underlying medical conditions.

Incidence by Age Group

The incidence of knee pain increases with age, with about 25% of individuals over 55 experiencing knee pain during a year. Aging is a significant risk factor for most common causes of knee pain, largely due to the natural wear and tear on the knee joints over time. The table below outlines the prevalence of knee pain by age group:

Age Group	Prevalence of Knee Pain
Under 55	Less than 25%
Over 55	25%

Factors Contributing to Knee Pain

Several factors contribute to the development of knee pain. Extra weight, for instance, often leads to knee pain as it places additional stress on the knees, which aren't designed to handle excessive weight [1].

Underlying medical conditions such as arthritis, gout, and infections can also result in knee pain. More than 100 different types of arthritis exist, with some varieties being more likely to affect the knee, contributing to knee pain across different age groups.

Injuries are another common cause of knee pain. Sports injuries, accidents, and falls can result in damage to the knee structure, leading to pain and discomfort.

Understanding the different factors contributing to knee pain is crucial for prevention and management. By managing modifiable risk factors such as weight and engaging in regular physical activity, individuals can reduce their risk of knee pain and improve their overall knee health.

Common Causes of Knee Pain

Knee pain is a common ailment that can affect individuals of all ages. There are numerous factors contributing to knee pain, with some being more prevalent than others. In this section, we'll delve into the most common cause of knee pain, osteoarthritis, and the risk factors that contribute to its development.

Osteoarthritis Overview

Osteoarthritis is the most common cause of knee pain and the most common reason for knee replacement surgery. This condition is characterized by the destruction of cartilage, thickening of the bone, and new bone formation. More than 100 different types of arthritis exist, with some varieties more likely to affect the knee, according to Mayo Clinic.

In a prospective study conducted between 1996 and 2008, the prevalence of moderate-to-severe knee osteoarthritis changed from 3.7% at the baseline assessment to 26.7% in the follow-up visit eleven years later. Middle-aged women had a high prevalence of moderate-to-severe knee osteoarthritis.

Risk Factors for Knee Pain

Various factors can increase the risk of developing knee pain, including age, obesity, high physical activity levels, and mental distress.

Obesity is consistently the main factor associated with knee osteoarthritis, with an odds ratio of 2.63. Obesity is also associated with hip and hand osteoarthritis, indicating that excess adipose tissue alters articular cartilage metabolism [3].

Interestingly, the prevalence of knee problems among young adults aged 18-39 was high at 31.8% among 314 participants, with knee pain being the most common dominant symptom (65%). Only high physical activity levels (OR 2.6 [95% CI 1.4–4.9]) and mental distress (OR 2.3 [95% CI 1.2–4.6]) were independent risk factors for knee problems.

Risk Factor	Odds Ratio
Obesity	2.63
High Physical Activity Level	2.6
Mental Distress	2.3

Understanding the common causes of knee pain and the associated risk factors is crucial for prevention and treatment. As the statistics on knee pain by age group show, both young and older individuals can experience knee pain, emphasizing the importance of early intervention and management strategies to mitigate the impact of this condition.

Knee Pain Statistics by Gender

When examining the statistics on knee pain by age group, it's also important to consider the disparities that occur based on gender. Understanding these differences can provide valuable insights into the prevalence, causes, and impacts of knee pain among different population groups.

Gender Disparities in Knee Pain

Research shows that there is a notable difference in the prevalence of knee pain between males and females. Females accounted for 55% of all patellofemoral pain cases compared to males, with 1,211,665 cases in females and 977,088 cases in males. Females also presented with patellofemoral pain more frequently than males in most age groups.

Furthermore, a study conducted on the elderly community population in Korea revealed that the prevalence of knee pain was 46.2%, with 32.2% in men and 58.0% in women. Women had significantly higher odds ratios for knee pain compared to men [6].

Gender	Prevalence of Knee Pain
Men	32.2%
Women	58.0%

Prevalence Across Age Groups

The prevalence of knee pain increases with age, particularly in women. However, regardless of age, the presence of knee osteoarthritis (OA) was significantly associated with knee pain in both genders. Interestingly, women had significantly higher odds ratios for knee pain compared to men among subjects both with and without knee osteoarthritis (OA). However, the presence of knee OA posed comparable risk for knee pain in both genders.

Furthermore, knee pain was correlated with a substantial reduction of physical function and quality of life (QOL) in both genders. Women with knee pain had significantly worse Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form 12 (SF-12) scores compared to men.

These findings highlight the importance of early detection and treatment of knee pain, particularly among women and older individuals. Through a combination of lifestyle modifications, physical therapy, and, if necessary, surgical interventions, individuals with knee pain can improve their quality of life and physical function.

Impact of Knee Pain

Knee pain, regardless of the age group, can significantly impact a person's daily life, from physical functioning to overall quality of life. The effects tend to vary based on factors like the severity of the pain, underlying causes, and the individual's overall health status. In this section, we delve into the specific impacts of knee pain.

Effects on Physical Function

Knee pain can severely affect physical function. According to a study cited by PubMed Central, subjects with knee pain had significantly worse scores on all Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscales, which measure pain, stiffness, and physical function in patients with hip and/or knee osteoarthritis. This was consistent even after adjusting for age, sex, and the presence of osteoarthritis.

Moreover, physical performance scores were worse among subjects with knee pain as opposed to those without it, particularly in females. It can be inferred from these statistics that knee pain can lead to a decrease in mobility, making it harder to perform common tasks that involve knee movement.

Quality of Life Implications

Beyond physical function, knee pain also has a substantial impact on an individual's quality of life. This was reflected in the findings of the same PubMed Central study, where knee pain subjects had significantly worse scores on almost all physical and mental domains of the Short Form 12 (SF-12) Health Survey compared to those without knee pain. The SF-12 is a measure of health status and outcomes from the patient's perspective.

Interestingly, the study also found gender disparities in these outcomes. Women with knee pain had worse WOMAC and SF-12 scores than men, indicating that knee pain might have more severe implications for women's quality of life.

The cumulative impact of these findings emphasizes the importance of managing knee pain effectively to preserve physical function and quality of life. These statistics on knee pain by age group underscore the need for increased awareness, early intervention, and comprehensive treatment strategies.

Treatment and Management

Dealing with knee pain involves a wide range of treatment and management strategies. These can be broadly classified into non-surgical and surgical procedures, depending on the severity and cause of the discomfort.

Non-Surgical Interventions

Non-surgical interventions are the initial course of action for managing knee pain. They are aimed at reducing pain, improving function, and delaying the need for surgery. According to MUSC Health, only about 2% of the 25% of people with knee pain will require a surgical procedure, underscoring the importance and effectiveness of these non-invasive interventions.

One common non-surgical intervention for knee pain, particularly for osteoarthritis - the most common cause of knee pain - is the use of intra-articular corticosteroid injections. These injections have been shown to reduce pain and improve function more effectively than control interventions for patients with knee osteoarthritis. However, their efficacy beyond 6 weeks post-injection remains uncertain due to the poor quality and variability in the studies [7].

Another non-surgical intervention involves the use of opioid medications for pain management. However, their efficacy is questionable, with only about 35% of patients who take opioids for osteoarthritis reporting pain improvement, compared to 31% of patients given a placebo for similar pain.

Surgical Procedures

When non-surgical interventions do not provide sufficient relief, surgical procedures may be considered. The most common surgical procedure for knee pain is knee replacement surgery, often necessitated by the destruction of cartilage, bone thickening, and new bone formation characteristic of severe osteoarthritis.

In the U.S., the rate of knee replacements among individuals aged ≥ 65 years increased about eight-fold from 1979 (10 per 10,000 population) to 2002 (80 per 10,000 population). By 2006, the rate increased further to 87 per 10,000 population in this age group.

Year	Knee replacements rate (per 10,000 population)
1979	10
2002	80
2006	87

Surgical procedures for knee pain, while more invasive, can provide significant relief for those suffering from severe discomfort and mobility issues. However, they should be considered as a last resort and are typically recommended when other treatment options have been exhausted.

Understanding these treatment and management strategies is crucial for those seeking relief from knee pain. It's important to consult with a healthcare provider to determine the best course of action based on individual needs and circumstances. As with any health condition, early detection and proactive management can significantly improve outcomes and enhance quality of life.

Future Trends in Knee Pain

As we investigate the future trends in knee pain, there are a couple of areas of focus: emerging research findings and potential public health implications. Both areas are critical to improving our understanding of knee pain and developing better strategies for managing it.

Emerging Research Findings

One of the emerging findings in the field of knee pain research pertains to knee osteoarthritis. This condition is globally prevalent with an incidence rate of 203 per 10,000 person-years in individuals aged 20 and over. Additionally, post-surgical pain is a significant concern, with around 20% of patients who undergo total knee arthroplasties experiencing chronic pain after the procedure. Moreover, the incidence of neuropathic post-surgical pain, concerning complex regional pain syndrome (CRPS), can be as high as 34% among post-arthroplasty patients [7].

An interesting revelation in terms of treatment is the use of opioids for knee pain and osteoarthritis. From 2004 to 2014, 16% of patients presenting with knee pain and osteoarthritis were prescribed opioid medications. However, the effectiveness of these medications for chronic use lacks empirical support. In fact, only about 35% of patients who take opioids for osteoarthritis report pain improvement, compared to 31% of patients who were given a placebo [7].

Another promising treatment method for knee osteoarthritis is intra-articular corticosteroid injections. These injections have been shown to reduce pain and improve function more effectively than control interventions. However, the efficacy of these injections beyond 6 weeks post-injection remains uncertain due to the poor quality and variability in the studies.

Potential Public Health Implications

Given the prevalence and disabling nature of knee pain, particularly due to osteoarthritis, it poses significant public health implications. Knee osteoarthritis affects 40 to 50 million Americans, with approximately 10–30% of those individuals experiencing significant pain, impaired function, and decreased quality of life.

Moreover, the financial burden of knee pain is enormous. The average cost of total knee arthroplasty (TKA) in 2015 was approximately $16,000 per discharge, totaling almost $10 billion in inpatient costs alone [7].

As the incidence of knee pain continues to rise, so will its impact on public health. It underlines the need for better prevention strategies, more effective treatments, and robust research to understand the complexities of knee pain and its consequences.