Image 1
X ray of knee joint in a 79 year old female patient demonstrates some classic radiolgical features of Osteoarthritis: The medial and patellofemoral compartment show a marked loss of joint space with osteophyte formation. An osteophyte is a bony projection that is associated with the degeneration of cartilage at joints. Also evident are subchondral cysts which are due to the subchondral (or underlying) bone hardening and thickening (known as sclerosis), as the cartilage tries to repair itself. Another feature of this x-ray is the vaccum phenomenon; this is when the joint has degenerated and as the cartillage erodes, gas (or air) enters  the joint.   Due to the degenerative changes there is also ‘genu varum’ (bow-leggedness).   Findings: Advanced Osteoarthrits.

What is the ‘Vaccum Phenomenon’

I think it could refer to the once yearly event when Hector actually gets the vaccum out!

Yeah, but vaccums suck, right?

Image 1 demonstrates very nicely the three classic radiological signs of Osteoarthritis which are, narrowing of the joint space, sclerosis (a hardening or thickening of the underlying bone) and osteophytosis which is a bony projection. Osteoarthritis is a degenerating joint disease that mainly affects the cartilage. Cartilage is a firm, elastic, connective tissue that covers the ends of bones and allows two bones to glide smoothly over one another. In Osteoarthritis the top layer of cartilage breaks down and the bones can rub together causing pain, inflammation and reduced mobility in the affected joint. The symptoms of Osteoarthritis vary greatly depending on the severity of the disease and the joint (or joints affected). The most commonly affected joints are the knees, hips, hands, and spine.⁽¹⁾ Less frequently affected locations are the elbow, shoulder and foot.

Image 2
  X-Ray of the right hip that illustrates the radiological features of advanced Osteoarthritis.  Clearly evident is complete loss of joint space with sclerosis, subchondral cysts and osteophyte formation.  Findings:  End Stage (Stage 4) Osteoarthritis.

 
Ostoearthritis of the hip is divided into 4 stages or grades ranked from 0-4, with grade 0 being a normal joint and grade 4 the most advanced or severe signs and symptoms of degneration caused by Osteorthritis⁽²⁾. Image 2 illustrates grade 4 because the joint space between the bones is severley reduced and the cartilage has almost completely gone. As well as the evident sclerosis and subchondral cysts, there is usually deformity of the femoral head and the socket of the hip joint. The synovial fluid is decreased and so there is little ‘cushioning’ of the joint which will be extremely painful and stiff at this stage, making walking or any movement extremely difficult. Osteorthritis is further classified into primary and secondary types, secondary arthritis is caused by other factors or diseases but the signs and symptoms remain the same.

Uncle Moose went to an ice cream parlour he slowly and painfully got up on to the stool and ordered a banana split, “Crushed nuts?” the waitress asked, “No, arthritis” he replied

Osteoarthritis is a very common disease and the leading cause of chronic disability in the United States. Worldwide it is estimated that around 250 million people have Osteoarthritis of the knee, which accounts for 3.6% of the total population.⁽³⁾ In the United States 27 million people are living with Ostoearthritis and 8 million people in the UK.⁽⁴⁾ Most adults over 55 years of age will have Osteoarthritis of some degree that is evident on radiography even if they are not symptomatic. The causes of Osteoarthritis are not exactly determined although genetics, gender, age, weight and ethnicity may all play a role. There is higher prevalence of osteoarthritis with advancing age and women are more likely than men to be affected.⁽⁵⁾

Footnotes

1. Pérez Martín Á. ‘Symptoms. Localizations: knee, hip, hands, spine, other localizations’ Aten Primaria. 2014 Jan;46 Suppl 1:11-7. doi: 10.1016/S0212-6567(14)70038-1.
2. Li KC, Higgs J, Aisen AM et-al. MRI in osteoarthritis of the hip: gradations of severity. Magn Reson Imaging. 6 (3): 229-36. – Pubmed citation
3. Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, Ezzati M, et al. (December 2012). “Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010”. Lancet380 (9859): 2163–96
4. Elsternwick (2013). “A problem worth solving.”. Arthritis and Osteoporosis Victoria
5. D’Ambrosia RD. ‘Epidemiology of osteoarthritis’. Orthopedics. 2005 Feb;28(2 Suppl):s201-5.

Sources

http://www.mypacs.net/cases/CLASSIC-OSTEOARTHRITIS-OF-THE-KNEE-WITH-MRI-COMPARISON-8425531.html
http://www.healio.com/~/media/Journals/ORTHO/2013/2_February/10_3928_01477447_20130122_04/fig1.jpg