• Skip to main content
  • Skip to primary sidebar
  • Skip to footer
  • General Ortho
  • Procedures
  • Spine
  • Upper Limb
  • Lower Limb
  • Pain
  • Trauma
  • Tumors
  • Newsletter/Updates

Bone and Spine

Orthopedic health, conditions and treatment

Recurrent Dislocation of Patella

By Dr Arun Pal Singh

In this article
    • Causes of  Recurrent Dislocation of Patella
      • Ligaments Laxity
      • Lateral Soft Tissue Contracture
      • Muscular Imbalance
      • Malalignment of the Lower Limb
      • Patella Alta
      • Injury
    • Presentation of Recurrent Lateral Dislocation and Subluxation
      • Apprehension test
      • Imaging
    • Treatment of Recurrent Dislocation of Patella
      • Congenital Dislocation of the Patella
      • Chronic Developmental Subluxation or Dislocation of Patella
      • Post-Traumatic Recurrent Lateral Subluxation or Dislocation
      • Patellar Subluxation with Lateral Pressure Syndrome

Recurrent dislocation of the patella is not a common entity. It may be congenital, developmental, or post-traumatic.

In contrast, recurrent subluxation of the patella is quite common. It is more common in females.

Causes of  Recurrent Dislocation of Patella

Ligaments Laxity

In children with diseases that cause ligamentous laxity (e.g. osteogenesis imperfecta, arachnodactyly, or the Ehlers-Danlos syndrome), lateral dislocation of the patella is more common.

Lateral Soft Tissue Contracture

Taut lateral patellar retinaculum and patellofemoral ligament contracted and hypertrophied vastus lateralis and tight iliotibial tract may contribute to dislocation of the patella.

Muscular Imbalance

Atrophy, weakness, or a high oblique insertion of the vastus medialis is a factor in most patients. The vastus medialis is a dynamic medial stabilizer of the patella.

Malalignment of the Lower Limb

Lateral tibiofibular torsion and genu valgum will displace the insertion of the patellar ligament laterally and cause valgus position of the quadriceps mechanism.

Q angle is the angle formed between the patellar tendon with a vertical line extended distally from the center of the inferior pole of the patella. Its value can provide a guide to the rotatory-angular forces.

Patella Alta

This is a high riding patella. In this, the normal buttressing effect of the lateral femoral condyle, which serves to check the tendency to lateral patellar displacement, will be lost.

Injury

A traumatic lateral dislocation inadequately treated will result in stretching and weakening of the medial capsule of the knee and insufficiency of the vastus medialis, predisposing to recurrent lateral subluxation.

Presentation of Recurrent Lateral Dislocation and Subluxation

The typical patient is a teenage girl who becomes physically active in exercises or sports. The presenting complaint is a pain in the knee in around or behind the patella, especially on flexion.

There may be symptoms of giving a way of knee and a swelling might be present in the knee.  Locking and popping of the knee may also be present.

The dislocation is precipitated by a sudden contraction of the quadriceps muscle when the tibia is in lateral rotation and the knee is in extension or slight flexion.

A dislocated patella is obvious on examination but the patient of recurrent dislocation is usually seen between the episodes.

In these patients apprehension test is quite confirmatory.

Apprehension test

While attempting to displace the patella laterally with the knee flexed 30 degrees and the quadriceps relaxed, exert laterally directed pressure with both thumbs pressing on the medial side of the patella.

The patient becomes fearful and uncomfortable when the patella reaches the point of maximum displacement and will resist and seize the examiner’s hand and straighten her knee to replace the patella in its relatively normal position.

This is referred to as Fairbank’s apprehension test.

With knee extended, the sense of apprehension is not elicited. This happens because the patella moves readily on the flat condylar and supracondylar surface of the femur and not across the highest point of the lateral condyle.

Another finding that may be noted during the examination is a limited excursion of the patella medially with the knee in extension. The lateral soft tissue might be taut.

Tenderness may be elicited on compression of the patella and palpation over the medial retinaculum.

Knee deformities like genu valgum and lateral torsional deformity of the tibia are usually present.

The patellar tendon may insert laterally with an abnormal increase of the Q angle.

In case of high riding patella, the tendon may be elongated with a high-riding patella.  Hamstring spasm and knee swelling may be present

Imaging

In between the episodes, x-rays may entirely be normal. Patella alta [high riding patella] and osteochondral fractures should be looked for.

Xray of Dislocation of Patella
Xray of Dislocation of Patella, Image Credit: Wikipedia

CT scanning should be done in the cases where plain radiographs are indeterminate. It may show may reveal occult osteochondral fractures and may reproduce patellofemoral relationships.

MRI may show bone bruises in the medial aspect of the patella and the lateral aspect of the lateral femoral condyle.

Treatment of Recurrent Dislocation of Patella

The treatment of patellofemoral joint subluxation depends on the following factors.

  • Degree of lateral displacement of the patella
  • Mechanism or type of subluxation or dislocation-whether it is due to
    • Malalignment of the quadriceps mechanism with contracture of the lateral patellar retinaculum and iliotibial band.
    • Muscle imbalance between a weak and high oblique vastus medialis and a hypertrophied, low, and transverse vastus lateralis
    • Extreme ligamentous hyperlaxity
    • Trauma resulting weakening of the vastus medialis.
    • Malposition of the patella
    • Angular or rotational deformity of the knee and leg
    • Presence or absence of bony hypoplasia of the lateral femoral condyle.
  • Presence or absence of chondromalacia of the patella.
  • Age
  • Psychological aspects

A rough guide to the management of this condition is as follow

Congenital Dislocation of the Patella

  • Marked soft-tissue contracture of the lateral side of the knee
  • Malalignment and contracture of the quadriceps mechanism
  • Secondary developmental structural changes
    • Shallow femoral sulcus
    • Hypoplasia of the patella.

Treatment

  • Surgical replacement of the patella in the femoral sulcus by
    • Release and lengthening of all lateral contracted soft-tissue structures
    • Tautening of the medial capsule and retinaculum
    • Distal and lateral advancement of the vastus medialis
    • Tenodesis of the semitendinosus to the patella
    • Shortening of the patellar tendon by distal-medial transfer.

Chronic Developmental Subluxation or Dislocation of Patella

These are  associated with

  • Severe ligamentous hyeprlaxity
  • Genu valgum
  • Hypoplasia of the lateral femoral condyle.
  • Patella alta may be present
  • Contracture and malalignment of the vastus lateralis
  • High insertion and hypoplasia of the vastus medialis.

Treatment

  • Surgical relocation of the patella
  • Realignment of the quadriceps muscle
  • Tenodesis of the semitendinosus tendon to the patella if Patella Alta is there.

Post-Traumatic Recurrent Lateral Subluxation or Dislocation

The great majority of acute patellar dislocations are lateral. Occasionally, however, they may be medial, intra-articular, or superior.

Acute dislocations associated with osteochondral fracture require surgical treatment. The fragment is removed or reattached along with soft tissue repair.

Nonoperative management is followed if examination of the aspirated blood from the knee does not show fat droplets and there is no evidence of osteochondral fracture.

In doubt, the diagnostic arthroscopic examination may be conducted

Nonoperative treatment

  • Immobilization of the knee in an above-knee cylinder cast for three to four weeks
  • Rehabilitation exercises for the quadriceps and hamstrings after that.

Recurrent post-traumatic dislocations require surgical intervention.

Recurrent post-traumatic subluxations an initial period of conservative management should always be tried. If it fails, operative treatment is indicated

  • Release of the lateral patellar retinaculum and vastus lateralis
  • Tautening of the medial capsule and medial patellar retinaculum
  • Distal lateral transfer of the vastus medialis.

Patellar Subluxation with Lateral Pressure Syndrome

The initial treatment should be nonsurgical, particularly when the associated chondromalacia is not severe. The nonoperative treatment includes

  • Exercises restore the motor strength of the quadriceps femoris, and especially vastus medialis.

The exercises should be isometric. Isotonic exercises should not be performed, as they markedly increase the patello-femoral load.

  • Hamstrings exercise
  • Descending and climbing stairs, bicycle riding, contact sports, and other strenuous physical activities are curtailed.
  • Analgesics and anti-inflammatory drugs

Operative measures are carried out when conservative management fails to relieve.

Save

Spread the Knowledge
  • 8
    Shares
  •  
    8
    Shares
  • 7
  •  
  • 1
  •  

Filed Under: Knee

ebook on fracture care

About Dr Arun Pal Singh

Arun Pal Singh is an orthopedic and trauma surgeon, founder and chief editor of this website. He works in Kanwar Bone and Spine Clinic, Dasuya, Hoshiarpur, Punjab.

This website is an effort to educate and support people and medical personnel on orthopedic issues and musculoskeletal health.

You can follow him on Facebook, Linkedin and Twitter

Reader Interactions

Comments

  1. Chanel says

    September 16, 2012 at 11:34 am

    I had dislocated my patella in fourth grade, I am now in 11 grade and having patella sublaxtions at least twice a week. Before I use to have them once I a blue moon and at random. I just thought It was strange tht it began to pick up during field hokey when before I had ran many races and marathons and I had no pain. I want to know if there is a way that I can get this fixed so that I can continue to play sports and not have to worry about always falling and dealing with a wry painful situation

  2. Dr Arun Pal Singh says

    October 19, 2012 at 9:33 pm

    Reecurrent dislocation of patella can be corrected surgically. But first we need to be sure of the diagnosis. Please see a doctor in person who would diagnose and guide you through the process.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Primary Sidebar

undifferentiated spondyloarthropathy image

Undifferentiated Spondyloarthropathy

Undifferentiated Spondyloarthropathy is a term used to describe the condition where presentation does not meet the criteria for a definitive diagnosis of ankylosing spondylitis or related disease. Undifferentiated spondyloarthropathy may represent an early phase or incomplete form of ankylosing spondylitis or another spondyloarthropathy. However, more recent data suggest that these patients may represent a distinct […]

hip osteoarthritis and normal hip

Hip Osteoarthritis – Causes, Symptoms and Treatment

This article focuses on hip osteoarthritis. For details on Osteoarthritis, read Osteoarthritis Symptoms, Diagnosis and Treatment Hip osteoarthritis is common and can result in severe pain and disability. It can make it hard to do everyday activities like bending over to tie a shoe, rising from a chair, or taking a short walk. It is […]

Enneking staging system for benign tumors

Enneking Staging System and TGNM Staging System for Musculoskeletal Tumors

Enneking Staging System and TGNM staging system are two main staging systems used for staging for benign and malignant tumors of the musculoskeletal system Many factors are involved in choosing the proper therapy for the patients. They include the stage of the disease, the expected functional result after surgery, the age of the patient, the […]

electron microscopy structure of osteon

Osteon or Haversian System and Its Significance

The osteon is the basic building block and fundamental functional unit of compact bone. It is also called a Haversian system, named after Clopton Havers, an English physician who worked extensively on the microstructure of the bone. Structurally, osteons are roughly cylindrical structures which are several millimeters long and around 0.2 mm in diameter. Structure […]

Fracture of Medial Condyle of Tibia

Knee Injuries Xrays and Clinical Photographs

knee injuries occur following trauma or fall. The knee is a major weight-bearing joint and the knee injuries require proper management with appropriate treatment. Following are few x-rays of knee injuries and other conditions of the knee. Image 1 – Knee Xray Showing Fracture Patella The image in the view shows a lateral view of the […]

Shin Splints are Common in Runners

Shin Splints or Medial tibial stress syndrome

Shin splints or Medial tibial stress syndrome is an overuse injury or repetitive stress injury of the shin area [tibial bone]. These affect persons who engage in running and jumping. It affects about 15% of all running-related injuries. It is most often found in runners, and persons playing other sports like football, basketball, soccer, and […]

Babygram or skeletal survey in congenital rubella syndrome

Skeletal Survey or Bone Survey – Indications and Uses

A skeletal survey is a series of x-rays which are done to view the entire skeleton, performed systematically to cover the entire skeleton or the anatomic regions as per clinical indications. Different clinical indications may demand a different set of x-rays. In the case of child abuse, which is a common indication, the local health […]

Browse Articles

Footer

Pages

  • About
    • Privacy Policy
    • Disclaimer
    • Contact

Featured Article

Congenital Pseudoarthrosis Of Clavicle

Congenital pseudoarthrosis of the clavicle is a rare anomaly and was first described by Fitzwilliams in 1910.Congenital pseudoarthrosis of … [Read More...] about Congenital Pseudoarthrosis Of Clavicle

Search Articles

© Copyright: BoneAndSpine.com