- BTS leader RM suffered an accessory navicular sprain and talus contusion during rehearsals.
- The injury involves a rare extra bone in the foot present in 4-21% of the global population.
- Symptoms include a bony bump, swelling, throbbing pain, and possible flatfoot issues.
The global K-pop community was left in shock on March 20, 2026, when BigHit Music confirmed that BTS's leader RM (Kim Nam-joon) sustained a significant ankle injury. This happened during rehearsals for the group's highly anticipated 'ARIRANG' comeback concert. According to an official statement from the label, medical examinations revealed that a sprain of the accessory navicular, a partial ligament tear, and a talus contusion (bone bruising) were the cause of the injury that occurred on March 19th, 2026, during dance rehearsals. While the rapper has expressed a firm desire to perform at the Gwanghwamun Square event on March 21, he will do so with limited choreography and a leg cast.
According to a meta-analysis published in the journal Surgical and Radiologic Anatomy, accessory navicular sprain is a painful condition that happens due to the navicular bone becoming bruised. But what exactly is an accessory navicular sprain, and what are the key details about it?
What Is An Accessory Navicular Bone?
For most people, the foot is a complex structure of 26 bones. However, about 4% to 21% of the global population is born with an ‘extra' bone called the accessory navicular. This is a present-at-birth or congenital condition where a small piece of cartilage or bone develops into a secondary ossification centre on the inner side of the foot, just above the arch.
In India, a 2025 study published in the Journal of Orthopaedic Case Reports found that nearly 24.5% of the Indian population may actually have this extra bone, often without even knowing it.
The Anatomy Of A Sprain
An accessory navicular sprain occurs when the bridge (either cartilage or fibrous tissue) that connects this extra bone to the main navicular bone is injured. Because the posterior tibial tendon, which is one of the most important tendons for supporting your foot arch, attaches right at this spot, any injury here can be incredibly painful.
In this particular case, when RM rehearses high-intensity choreography, the repeated stress can cause 'micro-trauma'. A sudden twist or impact can then lead to a full-blown sprain, inflammation, and the ‘talus contusion' as mentioned by his medical team.
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Symptoms To Look Out For
If you have a persistent ache in your midfoot, you might be dealing with more than just a regular ankle sprain. Key symptoms of accessory navicular sprain include:
- Visible bony bump, which is a swelling on the inner side of the foot, just above the arch.
- Vague throbbing where the pain worsens after physical activity or standing for long periods.
- Redness and swelling due to localised inflammation over the bony prominence.
- Flatfoot issues may happen because of the tendon being compromised; the arch may appear to fall or flatten.
Why Indians Should Care
If you are wondering why you must know about this condition, you should know that it goes well beyond RM's injury. In India, many cases of accessory navicular syndrome go misdiagnosed as simple flat feet or general ankle weakness. Given Indians' need for traditional footwear that may lack proper arch support, especially while performing high-impact activities like dancing and sports, the prevalence of symptomatic cases (about 10.4% in symptomatic Indian patients) is a health factor that shouldn't be ignored.
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Treatment And Recovery For An Accessory Navicular Sprain
BigHit Music noted that RM has been advised to wear a cast and minimise movement for at least two weeks. Here is how this condition is typically managed:
- Immobilisation by using a cast or walking boot to allow the bridge between the bones to heal.
- Physical therapy involves strengthening the posterior tibial tendon to take the pressure off the extra bone.
- Orthotics, such as custom insoles, support the arch and prevent the bone from rubbing against shoes.
- Surgery (The Kidner Procedure) can be performed for chronic cases where conservative treatment fails. Surgeons may remove the extra bone entirely and reattach the tendon.
While RM's injury is not career-threatening, as confirmed by the artist himself in a recent livestream, it serves as a reminder that extra doesn't always mean better when it comes to anatomy. If you find yourself reaching for painkillers after a long walk or noticing a new bump on your foot, it might be time to consult an orthopaedic specialist.
Disclaimer: This content, including advice, provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.
