Swelling and Knee Function


The most read post on this blog deals with “Swelling, Effusion, Edema and Bruising – What’s the difference?”.  I will take the concept one step further and discuss how knee swelling or joint effusions impact your ability to control your knee extension when you walk.

So, you injure your knee and develop swelling inside the joint.  You may notice your knee giving way.  That means when you transfer weight onto your injured leg the knee buckles.  This is due to the quadriceps (front of your thigh) not contracting efficiently and hence not controlling the knee in extension.  Knee extension is vital in walking because it stabilizes the leg to accept the transferred weight from the opposite leg when you are in stance phase of gait.  If the knee is unable to go fully straight while stepping onto it you have difficulty swinging the other leg through to take another step.

This happens because of the swelling (and possibly pain too) within the joint.  A neural reflex is set up by distension of the joint structures.  It passes through the spinal cord and back to inhibit the quadriceps.  It is then difficult to contract them at the right time and with sufficient speed during the gait cycle.  Hence, unsafe walking and difficulty going up and down stairs, for example.  You may notice immediate deterioration of your ability to contract the quadriceps following injury with a joint effusion.

To regain quadriceps function and hence to restore normal and safe walking you must control the swelling (see earlier post on this topic), avoid increasing it by careful activity modification and do specific exercises to regain normal quadriceps function.  Physical therapists will instruct you in specific neuromuscular reeducation exercises to restore the quadriceps recruitment pattern.  Such exercises may include seated quad sets, straight leg raises or short arc quad recruitment.  These may be done with neuromuscular electrical stimulation (not TENS – that’s for pain and totally different type of current form) to facilitate recruitment of the muscle.  In addition, you will be given terminal knee extension exercises in standing such as straightening the knee against a wall with a towel roll behind your knee against the wall or fully extending your knee against tension created by an elastic sports cord.

So, controlling swelling in a joint is necessary to regain function of the muscles moving that joint.  This process is used in all knee injuries that result in joint effusions as well as in all postoperative rehabilitation, for example, following ACL reconstruction, meniscus repairs and debridement as well as total knee replacements.

What have you found helpful in the past?

What worked for you?  What didn’t?

Post your comments here so other people can learn from your experiences.  We would love to here from you.

Swelling, Edema, Effusion, Echymosis, Bruising: What’s the difference?


If you sprain your ankle severely you may hear your doctor and physical therapist mention the words swelling, edema, effusion or bruising. If you have surgery on your knee for a meniscus tear or a ligament reconstruction you will hear similar terms (and see them too!). What is that bruising and swollen area in the muscles in front of your shin (tibia) when you ding your lower leg on the corner of a coffee table?

The Definitions (Dorland’s Medical Dictionary):

Swelling is defined as “a transient abnormal enlargement or increase in volume of a body part or area not caused by proliferation of cells.” The good thing is that it is transient so, as we have all experienced, swelling subsides over time (see below for hints on treatment).  It is due to some form of trauma to the body such as an ankle sprain (the ankle looks bigger) or a muscle tear (larger girth of your thigh with a hamstring tear) or a surgery (which is really a trauma to the tissue). Fluid accumulates – the enlargement is not a consequence of cell division (proliferation) such as may occur with an enlargement due to cancer in a tissue or the enlargement seen in a bone from a healed fracture.
Edema is “the presence of abnormally large amounts of fluid in the intercellular tissue spaces of the body.”  Here fluid accumulates between the cells (intercellular). This may be a consequence of tissue trauma, poor circulation resulting in lower leg edema, heart failure, blood clots, lymph node resection as happens with breast cancer, renal failure,  pregnancy and cirrhosis to mention a few causes.  In outpatient musculoskeletal physical therapy we mostly see patients who have edema due to surgeries (e.g. knee replacements) or an injury causing tissue trauma.  We may treat someone who has a comorbidity (co-existing condition) which has resulted in edema but if caused by a particular medical condition your doctor will be treating it, not us.
An effusion is “the escape of fluid into a part or tissue, as an exudation or a transudation.”  An exudation is “the escape of fluid, cells, or cellular debris, from the blood vessels and their deposition in or on the tissues, usually due to inflammation.”  Inflammation may occur due to trauma or surgery.  Blood vessel walls become more permeable or may be compromised. Fluid and cells can thus escape from the artery or vein into the surrounding area. Transudation refers to the passage of fluid across a membrane or tissue surface (e.g. the synovial lining of the knee joint), which may or may not be due to inflammation. In physical therapy, we commonly see a joint effusion where fluid has accumulated in the joint.  This may follow a knee or shoulder surgery or an ankle sprain, for example.
Ecchymosis refers to “a small hemorrhagic spot in skin or mucous membrane, forming a nonelevated, rounded or irregular, blue or purplish patch.” This is a medical term for  bruising which is defined as “a superficial injury produced by impact without laceration.” Both describe blood leaking into the surrounding tissue. You know this one!  Remember biting your cheek when you were chewing gum?  Your mucous membrane inside your mouth went blue.  Next time you do it tell who you are with that you have just created some ecchymosis in the mucous membrane of your cheek!

In summary, based on the above definitions, you can safely say that swelling refers to the enlargement of the body part involved and the swelling is due to fluid accumulation (edema, effusion) or blood accumulation (ecchymosis, bruising).

How do we treat swelling, edema, effusion, ecchymosis and/or bruising?

  1. Rest, Ice, Compression, Elevation:  “RICE” is what we know it as.  Rest refers to the need to limit activity so as not to create further trauma.  However, rest is relative.  That means you should move the affected area or tissue gently to keep it mobile and prevent stiffness during this phase but not so much that you increase the pain and swelling associated there with. There are times when movement is contraindicated … think broken bones! Ice for the first 48 to 72 hours after an injury with resultant swelling. The goal is to limit fluid accumulation in the injured area by reducing blood flow to the area. Cold temperatures result in blood vessel vasoconstriction reducing blood flow to the area which decreases the inflammatory exudate (see ‘exudation” described above) or bleeding into the involved tissue or joint. Remember this: ICE IS NICE! Compression refers to the use of an elastic wrap to compress the injured area and thereby limit swelling. The amount of compression should not be so much that blood supply is cut off or pain is increased. Elevation serves to decrease the hydrostatic pressure in the affected body part by raising it above heart level. The reduced pressure decreases the exudate and increases fluid removal from the area.  Add in gentle motion and you have a complete package.
  2. Heat: Use heat after 72 hours with the purpose of increasing blood flow to the injured area to flush out the accumulated fluid and inflammatory by-products. Heat also improves tissue flexibility thus making movement easier which is another method employed to reduce fluid accumulation in a joint or tissue.
  3. Movement? Yes, you should keep the injured area moving gently unless you have been told not to by your doctor or physical therapist. Movement of the injured joint (e.g. ankle sprain) or tissue (contracting the injured muscle) promotes pumping of the blood from the site as well as limits stiffness.  As mentioned above, movement may be contraindicated … think broken bones!
  4. Limit aggravating activities. After the initial shock of the injury due to pain, swelling and the limited function often associated with it, you may feel ready to increase your activity level. This is fine but must be closely monitored so as not to increase the already present fluid accumulation and pain. Limiting aggravating activities but still moving as normally as possible promotes healing of the injured tissue. For example, if you sprain your ankle and it is swollen and bruised but you can tolerate walking on it without limping for 10 minutes on level surfaces without increasing your pain and fluid accumulation then do so but stop before your symptoms are aggravated. Or, if you strain your hamstrings you may be able to walk with a normal gait pattern on level ground but not negotiate stairs without increasing the pain and worsening the gait pattern. Therefore, limit the use of stairs. Recall, we want normal movement early on following the injury to promote tissue healing.
  5. Lymphatic drainage. This is a manual technique used by physical therapists who have additional training specifically in lymphedema management. It involves very gentle massage techniques in specific areas of the body in a particular order to stimulate lymph drainage.  It is particularly effective for edema control. In addition to the massage techniques used, you are taught how to wrap the affected limb to promote drainage between massage sessions. You may also be taught how to massage yourself as a home program. If you need this type of treatment, make sure you ask the clinician you schedule with if they have specific training in this area. You can also look for a physical therapist who has this training via the National Lymphedema Network at http://lymphnet.org/.

In summary, swelling may encompass the terms of edema, effusion, ecchymosis and bruising as long as there is an increase in volume (size) of a body part or tissue due to fluid accumulation. RICE is the treatment of choice immediately after an injury/surgery but heat and controlled movement should not be avoided. If you have lymphedema you should consult with a physical therapist with specialty training in lymphedema management.

YOU CALL TO ACTION!

  1. What have you found most helpful in addressing the above symptoms?  Post your ideas on this blog for others to read.
  2. Invite a friend who has recently had an injury or surgery to read this and post their experiences.
  3. Call us at any of our three clinics if you have any questions regarding the specific application techniques to avoid ice or heat burns:

Sparks location: 775-331-1199

South Reno location: 775-853-9966

Northwest location: 775-746-9222