The inside region of the shoulder has various structures that provide stability to the shoulder. These structures include the tendon attachment of the subscapularis muscle, the medial glenohumeral ligament, and the joint capsule. One or all of these three structures can be affected during an injury to the medial shoulder, either acutely or chronically. Chronic injuries can occur from repetitive quick turns, cutting, and overall overuse. Acute injuries can occur from slipping out in the front limbs on ice or hardwood floors or slipping while making a quick turn.
MSI is similar to a rotator cuff injury in a human. Medial shoulder injuries typically present with pain and lameness in a front limb. The pet may exhibit pain when the front limb is pulled away from the center of their body. They may also have excessive range of motion of the shoulder on special tests performed by our team or by an orthopedic specialist. It is not recommended that these tests be tried by pet owners at home as this could further damage the structures of the shoulder.
Medial shoulder instability is primarily diagnosed by a hands-on examination of the medial glenohumeral ligament, the subscapularis muscle, and joint capsule testing. Radiographs are often performed to rule out any bony involvement including fractures or bone spurs. A musculoskeletal ultrasound can also assess these soft tissue structures, but is often not definitive for determining the degree of injury to these structures. At Walking Paws Rehab, we commonly diagnose MSI injuries through our exam, radiographs, and ultrasound. To assess the degree of injury, arthroscopy may be recommended.
Treatment of medial shoulder instability is dependent on the degree of injury. Surgery may be performed in more severe cases. For instance, if the ligaments, tendon, or capsule is completely torn, surgery may be the best route to bring the ligament or tendon back together. In mild or moderate cases, rehab alone is often sufficient. We also may recommend the use of hobbles, which is a vest that is worn to protect the front limbs from excessive motion and to decrease the risk of re-injury. Hobbles need to be measured prior to ordering so that they fit your pet appropriately. Average wear time depends on the severity of injury, but pets generally wear these for at least 7-8 weeks, sometimes up to 12-16 weeks in more severe cases.
In physical therapy, our initial goals are to decrease inflammation and increase blood flow to the affected area. As your pet is healing, their body will begin to lay down scar tissue. Initially scar tissue is weak and disorganized, and over time the body remodels that scar tissue into healthier stronger tissue. Many of our early therapies in rehab are focused on helping this process. Modalities like laser, ultrasound, and shockwave can be helpful for the formation of healthy, strong scar tissue. When appropriate, we start simple exercises. Our initial exercises are focused on helping your pet hold static positions, then we gradually progress to more dynamic exercises. Eventually we work toward exercises that match the demand that will be placed on the shoulder as your pet goes back to their normal activity. At each phase, we make sure your pet can tolerate the load without experiencing increased lameness before progressing to more difficult exercises. Regenerative medicine can also be helpful for these injuries to promote the remodeling process.
