Injuries usually derive from what happened. This is about instability, the consequences of an ankle joint dislocation, SLAP cracks and the wrong joint.

Shoulder Instability (Dislocation, Partial Dislocation)

Dislocation or partial dislocation (subluxation) occurs most frequently in the shoulder joint compared to any other joint. This is due to its unique structure: The almost spherical joint head, located at the upper end of the humerus, meets a small, relatively flat depression on the shoulder blade serving as the joint socket. In the case of subluxation, the humerus head shifts within the shoulder but does not fully dislocate.

Dislocation can occur, for example, from falling onto an outstretched arm, causing the humerus head to pop out of the socket. Individuals engaged in physical activities face a relatively high risk of recurrent incidents after the initial dislocation. Concurrent injuries to the cartilage or bone edge of the joint socket, such as a Bankart lesion in the lower area, can result in persistent shoulder instability if the damage does not heal properly. Additionally, the bump on the humerus head, an important tendon attachment point, can tear off. Nerve or vessel injuries are also possible. A significant tear in the rotator cuff tendon, leading to impaired muscle function, can also result in excessive shoulder immobility.

Dislocations or partial dislocations (unstable shoulder, subluxation) can also occur due to structural deviations, such as a too-wide joint capsule or a too-small joint socket. Sometimes, inadequate development of capsule and ligament tissue or muscles due to inherent factors contributes to this.

Symptoms:

Dislocation causes painful arm positioning depending on the type of dislocation. For instance, the arm is often held close to the body or at an angle. Passive movement is also painful. Swelling may occur if ligaments are strained or bruised. Nerve injuries may cause reduced sensation in the shoulder, less commonly in the arm, and possibly muscle paralysis, such as in the deltoid muscle. Particularly with accompanying joint socket injuries, the shoulder may dislocate again when the arm is raised and rotated outward.

A “snap” sensation in the shoulder is also possible. An unstable (subluxated) shoulder without other injuries manifests with vague symptoms, such as a sensation of the arm being too loose and easily movable. Habitual “dislocations,” i.e., very lax shoulders, are not painful and differ from instability, which is a pathological condition but should still be prevented.

SLAP Tears

SLAP stands for “superior labrum anterior to posterior,” referring to the upper lip-shaped reinforcement of the joint socket consisting of cartilage and connective tissue. It assists in stabilizing the humerus head position and serves as the attachment point for ligaments and the biceps tendon. SLAP tears, which may occur after previous dislocations (as mentioned above) or other shoulder injuries like biceps tendon tears, primarily affect overhead athletes, workers, and throwing athletes.

Symptoms include shoulder pain in the front area, weakness, or limited shoulder movement, but no pain when lying on the shoulder (nocturnal pain) and no audible joint “locks.” A characteristic sign of a biceps tendon tear is the “Popeye deformity,” where two muscle bulges are visible on the bent upper arm: the ball-like shortened biceps and the deltoid muscle. SLAP tears have different forms.

Diagnosis

Dislocation: Diagnosis is based on arm positioning, injury description, and functional testing. The doctor may feel and observe the humerus head slipping (dent). Evaluation of blood flow, sensation, and muscle function (for possible nerve damage) is standard in any shoulder-arm injury. X-rays reveal the empty socket, while suspected accompanying injuries can be identified through magnetic resonance tomography.

For SLAP injuries and unstable shoulder conditions, x-rays are typically normal. Diagnosis relies on clinical movement tests, medical history, and ultrasound scans. Magnetic resonance tomography (MRT) or, in rare cases, computed tomography (CT) with arthrography may be necessary, alongside arthroscopy.

Therapy

Dislocation: Treatment involves repositioning under local or general anesthesia, potentially followed by operative stabilization (arthroscopic or open) and treatment of accompanying injuries. Surgically addressing a predisposed dislocating shoulder is also common. The repositioned shoulder is temporarily immobilized with a bandage, followed by physiotherapy to restore full shoulder functionality and potentially resume sports activities.

Unstable Shoulder: Physiotherapy-based rehabilitation program, with stabilizing interventions for persistent symptoms, such as arthroscopy if needed.

SLAP Tear: Conservative treatment is preferred, focusing on pain management and exercise therapy, with surgery reserved for specific cases like competitive athletes and highly specialized workers.

Split Shoulder Joint, False Joint, and Other Consequences of Injuries

A completely torn ligament is typically the precursor to a split shoulder joint, more prevalent in younger, physically active individuals. Joint wear and tear (osteoarthritis) may ensue from uneven healing, leading to conditions like acromioclavicular joint osteoarthritis, the most common form of shoulder osteoarthritis. Unstable fractures in the humerus may result in painful pseudarthrosis, where the fracture fails to heal, forming a false joint. Treatment depends on the specific cause and often involves surgery.

A newer treatment are PRP injections into the joint. These seem to be successful for various joint injuries and are performed by a variety of doctors.