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Imaging findings explained

Imaging explained

Whether it’s x-ray, ultrasound or MRI, the report seems to always contain some scary looking stuff. But here’s the thing – many changes are simply age-related and very normal. Others are transient and will go away in time. So here’s the low down on the most common ones. 


Osteophytes

Osteophytes are bone formations in response to load. They are often referred to as “bone spurs”.

Osteophytes primarily form due to compressive bony pressure, such as spinal osteophytes or tibial osteophytes, or due to abnormal pulling load from soft tissues, such as Calcaneal osteophytes (aka. heel spurs).

Osteophytes are only painful while they are forming, due to the process of bony irritation. Once they are no longer under load and reactive, they have no ongoing symptoms or complications in the majority of cases.


Baker’s cyst

A Baker’s cyst is a pocket of fluid that bulges thru the back of the knee joint. It occurs after significant or prolonged swelling from another pathology and can come and go based on the amount of knee fluid present. 

Symptoms of a Baker’s cyst include a loss of knee range due to pressure or pain in the back of the knee and a constant ache in the area. A ruptured Baker’s cyst causes sudden calf pain and tightness and is often mistaken for a strained calf muscle. Otherwise the ruptured cyst is harmless and doesn’t damage the integrity of the knee joint. 

The best solution for a Baker’s cyst is to reduce the amount of fluid in the knee with anti inflammatory meds and strength work and avoid aggravating positions such as crouching, twisting and jumping. 


Bone edema/oedema

Bone oedema is a painful but temporary reaction in the bone which is most commonly caused by impact.

The bone shows increased signal inside the bone on MRI and bone scan. This bruised area is painful to load, causing a deep aching feeling during and after activity. 

Bone oedema will feel better with ice, heat or medication but these won’t shorten the duration of the episode. 


Osteochondral defect or lesion

This refers to damage to the hard joint cartilage that lines the end of the bone. It can occur as a result of a single incident, such as a sprained ankle, or due to gradual wear, such as in osteoarthritis. 

Lesions or defects can be isolated, with a single “chunk” missing, or widespread, with an area of wear of differing depths. The depth of the lesions are graded from 1-4, with grade 4 being full depth lesions thru to the underlying bone. 

Although osteochondral cartilage doesn’t repair, it’s no longer symptomatic once the load applied to it is controlled and not excessive. Strength work and weight loss are the most effective approaches.


Subchondral cysts

This refers to small pockets fluid under the cartilage (surface) of the joint. 

They form when the cartilage is disrupted due to wear or an injury, leaving a gap for the joint fluid to press in to, causing a hole or “cyst” in the bone underneath the cartilage. 

These cysts can become painful when the knee has an excess of fluid in it, often due to another pathology in the knee, which increases the pressure on the cysts and causes the surrounding bone to ache. 


Synovitis

This is an inflammatory reaction of synovium, the sensitive lining on the inside of joint capsules and tendon sheaths. 

This reaction occurs when excessive load is applied to the synovium, either via sudden stretch (eg. rolled ankle) or prolonged pressure (eg. joint swelling). In most cases the affected area is painful to touch or stretch. 

The most effective treatment combines ice or anti-inflammatory meds and protection from further stretching (eg. taping or bracing).