Unstable Kneecap Treatment

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Dr Poh Seng Yew



MMED (Ortho)



What is Kneecap Instability?

Kneecap instability refers to a condition where the patella, commonly known as the kneecap, moves out of its normal position within the knee joint. The patella, a small bone located at the front of the knee, acts as a fulcrum for thigh muscles to extend the leg. Instability can occur when the patella does not track properly within its groove on the femur during knee movement.

This condition often leads to discomfort and impaired mobility. It can affect individuals of all ages but is more prevalent in younger, physically active populations.

Causes of Kneecap Instability

Kneecap instability arises from a combination of factors that disrupt the normal alignment and movement of the patella.

  • Anatomical Variations
    Individuals may have congenital differences in the structure of their knee joint which predispose them to instability.
  • Muscular Imbalances
    Weakness or imbalance in the muscles around the knee, particularly the quadriceps, can lead to improper patellar tracking.
  • Ligamentous Laxity
    Some people have more flexible ligaments, which can result in a higher likelihood of patellar dislocation.
  • Trauma and Injury
    Acute injuries, such as a blow to the knee or a severe twisting movement, can disrupt the patella’s alignment.
  • Repetitive Stress
    Athletes or individuals engaging in high-impact or repetitive knee activities are at an increased risk due to the strain placed on the patellofemoral joint.

Symptoms and Signs

The symptoms and signs of kneecap instability can vary based on the severity and frequency of the instability episodes.

  • Recurrent Dislocation: The kneecap may visibly move out of place, as it dislocates from the groove. Often the kneecap realigns to its correct position autonomously, but in some cases, medical intervention may be required.
  • Subluxation: This refers to the partial dislocation of the kneecap, where it partially comes out of its normal position in the knee joint. This can cause sudden pain and a feeling of the knee being unstable or about to give way.
  • Pain: This is often experienced around the knee, and may worsen during activities such as running, squatting, or climbing stairs.
  • Swelling: The knee may swell following a dislocation episode or due to chronic instability.
  • Difficulty in Straightening the Knee: This can occur particularly after a dislocation when the kneecap may not return to its normal position.


Diagnosing kneecap instability involves a combination of clinical evaluation and imaging studies.

  • Clinical Examination
    The knee’s range of motion, stability, alignment, and strength will be assessed. The examination may include specific manoeuvres to elicit symptoms of patellar instability.
  • Medical History
    A detailed history, focusing on previous knee injuries, episodes of instability, and any familial history of similar issues, is reviewed.
  • Imaging Tests
    X-rays can reveal the alignment of the patella and detect any bone abnormalities. An MRI provides detailed images of the soft tissues, including ligaments and cartilage, to assess damage or congenital abnormalities contributing to instability. Occasionally, a CT scan is also used to evaluate the alignment of the knee joint and patella more precisely.

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Non-Surgical Treatment Options

Non-surgical methods are often used in instances of mild to moderate kneecap instability. They focus on relieving symptoms and strengthening the knee to prevent future episodes.

RICE Method

This stands for Rest, Ice, Compression, and Elevation. It involves resting the affected knee, applying ice to reduce swelling, using compression bandages to support the knee, and elevating the leg to decrease swelling.

Bracing and Taping

Knee braces or patellar taping methods are employed to provide external support to the knee, ensuring the kneecap remains aligned within its groove during physical activities.

Pain Management Strategies

Over-the-counter pain medications and anti-inflammatory drugs can be used to manage pain and reduce inflammation in the knee.

Targeted Physiotherapy

After a period of rest, personalised exercise programs can be used to strengthen the quadriceps, hamstrings, and hip abductor muscles. This aims to improve the stability and alignment of the patella during movement.

Surgical Treatment Options

In cases where non-surgical treatments do not yield the desired results, or when the instability is severe or recurrent, surgical intervention may be considered.

  • Medial Patellofemoral Ligament Repair
    This procedure treats chronic patellar instability. It involves strengthening and repairing the ligaments that keep the kneecap in place, specifically the medial patellofemoral ligament. This surgery aims to restore the stability of the patella, thereby reducing the risk of dislocation and improving knee function.
  • Ligament Reconstruction
    This involves replacing a damaged knee ligament with a graft. The graft may be sourced from a donor or another part of the patient’s body.
  • Knee Osteotomy
    This surgical procedure realigns the thigh bone, shin bone, kneecap, and surrounding tissues. It helps correct bone alignment issues contributing to instability.
  • Knee Replacement
    In extremely severe cases, where other treatments fail to relieve pain and restore function, a knee replacement may be the best option. This involves replacing parts of the knee joint with artificial components.

Prevention Strategies

Preventing kneecap instability involves measures aimed at minimising the risk factors and strengthening the knee joint.

  • Strengthening Exercises: Regular exercises that focus on strengthening the quadriceps, hamstrings, and hip muscles can help maintain proper patellar alignment.
  • Proper Technique in Sports: Athletes should be trained in techniques that reduce stress on the knees, such as proper jumping and landing methods.
  • Appropriate Footwear: Wearing shoes that provide good support can help maintain proper leg alignment and reduce stress on the knees.
  • Maintaining a Healthy Weight: Excess weight can increase the strain on knee joints, so managing body weight is beneficial.
  • Warm-Up and Stretching: Before engaging in physical activity, a proper warm-up and stretching routine can help prevent injuries.
  • Avoiding Overuse: Limiting activities that put excessive stress on the knees, especially if symptoms of discomfort or instability are present.

Dr Poh Seng Yew



MMED (Ortho)


With over 20 years of experience, Dr Poh Seng Yew is an orthopaedic surgeon specialising in hip, knee, shoulder and elbow surgery, sports medicine, and trauma surgery.

  • Former Director of Sports Service, Department of Orthopaedic Surgery, Singapore General Hospital
  • Clinical Hip and Sports Medicine Fellow, Orthopädische Chirurgie München (OCM), Germany
  • Fellow, Royal College of Surgeons of Edinburgh, FRCSEd (Orthopaedic Surgery)
  • Master of Medicine (Orthopaedic Surgery), National University of Singapore
  • Member, Royal College of Surgeons of Edinburgh (MRCSEd)
  • Bachelor of Medicine, Bachelor of Surgery (MBBS), National University of Singapore



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Mount Elizabeth Novena Specialist Centre
38 Irrawaddy Road, #08-62/63
Singapore 329563

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    Mount Elizabeth Novena Specialist Centre
    38 Irrawaddy Road, #08-62/63
    Singapore 329563

    Frequently Asked Questions (FAQ)

    Can kneecap instability be treated without surgery?

    Yes, many cases of kneecap instability can be effectively managed with non-surgical treatments such as physiotherapy, bracing, activity modification, pain management, and ice therapy.

    Are there specific exercises to prevent kneecap instability?

    Yes, exercises focusing on strengthening the quadriceps, hamstrings, and hip muscles can help prevent kneecap instability.

    When is surgery considered for kneecap instability?

    Surgery is considered when non-surgical treatments are not effective or in cases of severe or recurrent instability. The type of surgery depends on the individual’s specific condition.

    Can kneecap instability recur after treatment?

    There is a possibility of recurrence, especially if preventative measures are not maintained. Adhering to a rehabilitation program and lifestyle modifications can reduce this risk.

    How long does it take to recover from kneecap instability?

    Recovery time varies depending on the severity of the condition and the treatment approach. Non-surgical recovery may take a few weeks to several months, while surgical recovery can take longer.

    What are the long-term complications of untreated kneecap instability?

    If kneecap instability is not treated, it can lead to chronic pain and discomfort. Repeated dislocations or chronic instability can cause damage to the cartilage and soft tissues in the knee, potentially leading to early-onset arthritis.