Joint examination and evaluation is one of the three systems that must be evaluated prior to treatment. This article is a continuation of my previous article on muscle palpations. I briefly mentioned how important it was to be aware of the patient's history of headaches and joint problems. It's very important to establish the baseline pain issues your patient has by asking them about medications they take, what they do to cause any pain, and how they make it better or worse.
As you examine the joint during the evaluation, you'll go through three different components to effectively examine your patient.
1. First component
Capsule and lateral ligament. I like to begin my evaluation with palpation over the lateral pole of the condyle, by placing my finger there and having the patient open and close. While placing your fingertip there, you'll be able to feel any clicking or popping if it exists. You'll also want to add slight pressure on the capsule and lateral ligament to test for any tenderness from inflammation. If there is any tenderness, the odds of inflammation are very high.
Retrodiscal tissue. The retrodiscal tissue is highly vascular, innervated tissue, which extends from the posterior portion of the disc to the posterior fossa. Normally this tissue is not under compression unless the disc migrates anteriorly, pulling the retrodiscal tissue across the head of the condyle and potentially producing compression and pain. In addition, if this tissue is compressed from trauma to the mandible it may begin to swell and exude pain, also.
This is often accompanied by the lateral pterygoid muscle contracting to try and remove the compression from the swollen the retrodiscal tissue, which moves the mandible forward resulting in the patient not being able to touch their posterior teeth. There are a couple of ways to palpate this tissue: laterally, by rolling your fingertip from the posterior portion of the condyle into the space behind the condyle, or by putting your finger in the external auditory meatus and pushing very lightly down and forward.
Ligament laxity. If you're checking the retrodiscal tissue via the external auditory meatus, you can evaluate for ligament laxity. For a disc to be displaced anteriorly, the ligament that attaches the disc to the condyle has to be elongated or torn. Physically, you can check this by inserting your fingertip in the external auditory meatus and pushing forward with minimal pressure. While doing this ask the patient to open and close. A patient who has a disc in a normal position but has ligament laxity will feel a pop when opening and closing when you are pushing forward, but not when you remove the pressure.
2. Second component
Range of motion. You can check how far the patient can move left, right, and the amount they protrude. In addition, measure the amount they can open. All of these movements are measured to evaluate the joint's ability to translate. Any limitations of movement may be signs of an abnormal disc condyle relationship. You should also check to see if the patient has any deviations from side to side upon opening, which are signs of one joint translating faster then the other, another potential indication of an intracapsular problem. If the patient has any discomfort during the movements it may also be a potential sign of a joint problem, but it also could be muscle and may require appliance therapy to make a final diagnosis.
3. Third component
Load test. Load testing is the final phase of the joint evaluation, and can be completed by using bilateral manipulation or an anterior deprogrammer. In this step you will place a superior load on the condyle to determine if the condyle can be compressed comfortably.
Load testing really evaluates three things: the joint, the lateral pterygoid muscle, and if there is edema in the retrodiscal tissue. If the patient has pain on loading, otherwise known as a positive load test, the pain is most likely stemming from the lateral pterygoid muscle being stretched as the condyle is trying to seat superiorly, but may be from an anteriorly displaced disc allowing the condyle to compress the retrodiscal tissue, or a disc in a normal position with inflamed and edematous retrodiscal tissue.
Any positive load test is followed by chairside deprogramming with devices such as a Lucia jig to evalauate if the discomfort becomes greater or subsides. If the discomfort reduces or disappears after 10 to 20 on a Lucia jig, the problem is most the likely lateral pterygoid muscle. If it doesn't, it will require appliance therapy to aid in the diagnosis.
These three phases of joint evaluation may seem like they will take up a lot of time, but the reality is that it only takes about five minutes to perform in a normal asymptomatic patient. However, it will take longer if you have a patient that has symptoms; but at least now both you and your patient are aware that an issue exists and can begin corrective treatment.