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While the occasional knuckle crack is unlikely to harm joints or lead to arthritis, excessive or forceful cracking could potentially contribute to joint stress over time.
Experts agree that as long as there’s no associated pain, swelling, or discomfort, cracking joints is generally safe. However, forceful manipulation, particularly by untrained individuals, carries the risk of injury
The satisfying pop of cracking knuckles, backs, or ankles is a familiar sensation to many. Whether it’s a post-workout stretch, a nervous habit, or just a way to relieve tension, joint cracking has been a subject of curiosity and concern. But does this habit actually cause arthritis? Experts in orthopedics and sports medicine clarify the science behind joint cracking and its effects on long-term joint health.
What Causes the Popping Sound?
The distinctive popping sound when cracking knuckles comes from the joints. Dr. Prakash Ayyadurai, Senior Consultant in Arthroscopy & Sports Medicine, Rela Hospital, Chennai, explains that the joints are surrounded by synovial fluid, which acts as a lubricant. “When a joint is pulled or flexed, pressure changes in the synovial fluid cause the formation of gas bubbles, which then burst, producing the characteristic ‘pop.’ It takes about 20 minutes for these gases—oxygen, carbon dioxide, and nitrogen—to reabsorb, which is why the same joint cannot be cracked again immediately.”
Dr. Shriram Krishnamoorthy, Orthopedic Surgeon, MGM Healthcare Malar, Chennai, adds that some people are also able to crack their joints at will due to snapping tendons and ligaments. While this is usually harmless, it can sometimes lead to mild discomfort.
Does Joint Cracking Lead to Arthritis?
A long-standing concern is whether cracking knuckles contributes to arthritis. Scientific research has largely debunked this myth. Dr. Ayyadurai refers to the famous study by Dr. Donald Unger, who cracked the knuckles of only one hand for 50 years without developing arthritis in either hand. “While this study is not definitive, it strongly suggests that habitual joint cracking does not directly cause arthritis,” he explains.
Dr. V. Sudhir, Senior Consultant, SRM Global Hospitals, Chennai, concurs, stating that “knuckle cracking does not cause arthritis. However, excessive twisting or pulling beyond a joint’s capacity can cause sprains and even fractures, which can be harmful.” He points out that in India, knuckle cracking is often a social habit, particularly among women in group settings and men who do it as a nervous tic. While mostly harmless, any cracking that results in pain, swelling, or numbness should be immediately discontinued.
Dr. Krishnamoorthy reinforces this perspective, noting that while cracking joints doesn’t inherently lead to arthritis, excessive force could gradually wear down the cartilage. “Cartilage acts as a cushion between bones, and repeated strain over time could contribute to joint problems. While there’s no strong evidence linking cracking knuckles to arthritis, chronic overuse and forceful cracking might contribute to joint wear and tear.”
When Is Cracking Joints a Cause for Concern?
Though cracking knuckles is generally harmless, there are certain instances where it may signal an underlying issue. According to Dr. Ayyadurai, viral videos showcasing extreme joint manipulations can be concerning. “While self-induced cracking is usually safe, attempting to crack someone else’s joints or performing forceful manipulations without proper knowledge can lead to soft tissue contusions, ligament injuries, sprains, strains, and even fractures.”
Dr. Sudhir also warns that any joint cracking accompanied by pain, swelling, or stiffness should not be ignored. “If someone experiences discomfort after cracking their knuckles, they should stop immediately and consult a doctor if symptoms persist.”
While the occasional knuckle crack is unlikely to harm joints or lead to arthritis, excessive or forceful cracking could potentially contribute to joint stress over time. Experts agree that as long as there’s no associated pain, swelling, or discomfort, cracking joints is generally safe. However, forceful manipulation, particularly by untrained individuals, carries the risk of injury.
As Dr. Ayyadurai aptly puts it, “Protecting joint health means understanding the mechanics of the body and avoiding harmful practices. While an occasional pop might be satisfying, it’s best to avoid forceful or excessive joint cracking.”
