Why Does My Joint Hurt?

joint replacementAny event, continued malalignment or disease process (i.e. inflammation) that injures the cartilage may cause joint damage or arthritis. A small cartilage injury may become larger and lead to widespread cartilage loss or degenerative joint disease over time. A variety of events can damage cartilage, including trauma (injury), infection, inflammation or a joint that is not properly aligned. A traumatic injury can cause an isolated defect, while malalignment tends to cause widespread damage to both sides of the joint. This is very similar to the way a car tire loses its tread when the wheels are not properly aligned.

Typically, as the “wear and tear” on the shoulder joint progresses, there are bone spurs or osteophytes that form on top of the bones. These bone spurs (osteophytes) can cause shoulder pain when the joint moves and can limit the motion of the joint. With time, the spurs become larger, the cartilage starts to wear away and the shoulder joint becomes stiff. In the shoulder, this condition is called Degenerative Joint Disease (DJD).

Osteonecrosis (AVN)

This condition is translated as “bone death” (osteo=bone, necrosis=death). Also known as avascular necrosis or AVN (avascular = loss of blood supply). Osteonecrosis is caused by lack of blood supply to the bone, resulting in the deterioration of bone tissue and the collapse of the bone. It can be triggered by a variety of factors including trauma, alcohol abuse, genetic abnormalities, pregnancy, systemic disease or corticosteroids use from receiving medical treatment (e.g., cancer treatments and organ transplantation). However, in approximately 25% of patients the cause is still unknown.

Traumatic Lesions

shoulder implant surgeryDamage to your shoulder can be caused by trauma, injury or previously failed surgeries. The most common type of traumatic injury is what is known as a “Hillsachs Lesion.” This type of lesion can occur when you have a shoulder dislocation. This is a very common injury that can occur from a force pushing your arm behind you, causing the head of the humerus to dislocate from the front of the shoulder. When this happens, the humeral head turns inside its socket until the back of the head meets the front of the glenoid. This occurrence causes the head to chip off bone and can even break a piece of bone from the front edge of the glenoid. The bone chipping can result in a lesion on the back of the head and it usually causes a tear of the labrum (soft tissue bumper) on the front edge of the glenoid. The labrum is usually repaired arthroscopically. The surgeon reattaches the torn soft tissue (labrum) using suture and anchors. When 30% or more of the head is chipped off, the Hillsachs lesion is sufficiently large enough to engage or catch on the front of the glenoid.

While not all Hillsachs lesions are painful, this catching can result in a sore shoulder and severely limit your motion. Over time, the repetitive catching can re-tear the labrum that was previously fixed. To stop this from happening again, the surgeon needs to fill the defect on the back of the head so that it stops catching. This can be accomplished by placing a HemiCAP® implant into the defect, restoring the shape of the humeral head and allowing it to articulate again without catching.

Another type of traumatic lesion can occur when the anchors used to fix soft tissue damage in your shoulder (i.e. rotator cuff repair) loosen and rub against the humeral head. This windshield wiper effect tears the surface cartilage, resulting in exposed bone and a painful lesion. A HemiCAP®, also known as a partial resurfacing, can be placed into the damaged area, covering the defect. This seals off the exposed bone to create a new smooth surface.