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Kneecap Instability; Causes, Symptoms, Treatment

Last updated: February 7, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 2 min read

The knee joint is one of the largest in the body, comprising of three bones – femur, tibia and the kneecap (patella). The kneecap fits into a groove like cavity in front of the femur called the trochlea. All these bones have a protective tissue lining around their surface to reduce friction between them. The quadriceps tendon that lies near the patella connects the quadriceps muscle to the tibia. In normal joints, the patella is placed in the center of the trochlea but in some people it is pulled to one side of the groove and does not slide within the cavity as the leg moves. This is known as Patellar Subluxation or Kneecap Instability. The condition is caused due to the following reasons:

  • The trochlea groove is inherently narrow or shallow and the kneecap bone is unable to fit into it
  • The pelvis is broader than normal
  • Abnormal gait stresses the knee joint and the patella tends to shift from its normal position
  • A fall on the knee may damage the knee cap alignment
  • A direct hit to the joint
  • Vehicular accidents

Symptoms

  • Discomfort while moving the joint
  • Patellofemoral Pain Syndrome- pain on the sides of the knee during movement
  • Inability to bear body weight
  • The knee buckles when the patient tries to move or stand
  • A feeling of locking or catching
  • Stiffness
  • A popping or cracking sound is heard or felt when the knee moves
  • Inflammation around the joint

Diagnosis

  • Thorough clinical examination of the affected joint to assess the severity of the condition
  • X-ray imaging to check if the patella has been dislocated
  • Analysis of the patient’s symptoms, medical history, gait etc.
  • MRI or CT scan to check for tendon or cartilage damage

Treatment

  • The orthopedic doctor may suggest certain exercises to strengthen the quadriceps, hip abductors and hamstring muscles
  • Bracing may be used to keep the joint stable and provide relief from the symptoms
  • Taping may provide support to the joint while moving
  • The patient may be recommended to wear special footwear that supports the legs and improve the gait
  • Manual reduction of the patella may be done
  • Recurrent incidences of dislocations need to be treated with arthroscopic surgery
  • Physical therapy may be recommended to improve functionality and enable the person to return back to his/her normal activities
  • Surgery may help to release the pressure from the tight tendons or ligaments that may be pulling the kneecap out of its place

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

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Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.