Shoulder Instability and Dislocation

Types of instability

Anterior instability is the most common pattern and usually occurs when the arm is forced away from the body and rotated outward. Posterior instability may follow trauma, repetitive loading, seizure, or electrocution. Multidirectional instability involves excessive translation in more than one direction and often occurs in patients with generalized laxity. A subluxation is a partial slipping event that may reduce on its own. A dislocation is complete separation of the joint surfaces and often requires urgent reduction.

Evaluation

The history identifies how the first event occurred, how many episodes have followed, whether the shoulder reduces on its own, and which positions create apprehension. The examination assesses direction of instability, ligament laxity, rotator cuff strength, motion, nerve function, and generalized hypermobility. X-rays evaluate fractures and bone defects. MRI or MR arthrogram assesses the labrum, capsule, rotator cuff, and cartilage. CT is particularly useful for measuring glenoid and humeral-head bone loss and planning bone-restoring surgery.

Nonsurgical treatment

Some first-time dislocations are initially treated with reduction, short-term protection, and rehabilitation. Therapy restores motion, rotator cuff strength, shoulder-blade control, and neuromuscular stability. Selected young contact or collision athletes and other high-risk patients may consider surgery after a first dislocation because the recurrence risk can be substantial. The decision should be individualized rather than based on a single age cutoff.

Surgical options

Arthroscopic Bankart repair reattaches the injured labrum and capsule to the glenoid. Capsular shift may be added when excessive capsular volume or laxity is present. Remplissage can address a clinically important Hill-Sachs defect by converting the defect into an extra-articular surface. When meaningful anterior glenoid bone loss is present, a Latarjet or another bone-restoring procedure may provide more reliable stability than soft-tissue repair alone. Posterior instability requires a different repair pattern and, in selected cases, bone reconstruction.

Recovery and return to sport

After surgery, the repaired structures are protected in a sling. Motion is restored gradually, followed by strengthening and sport-specific progression. Return to contact sports or throwing requires healing, appropriate motion, strength, stability, and confidence. Potential risks include recurrent instability, stiffness, loss of rotation, nerve injury, fracture, graft or hardware problems, arthritis, and additional surgery. The aim is to balance stability with the motion required for the patient's activities.

Selected References

1. Obana KK, Chen AZ, Rondon AJ, Wong TT, Jobin CM, Levine WN, Knudsen ML. Inter-rater reliability in calculating glenoid bone loss among orthopedic surgeons and musculoskeletal radiologists: how much do we agree? JSES Int. 2025;9(3):603-606.
2. Arenas-Miquelez A, Barco R, Cabo Cabo FJ, Hachem AI. Management of bone loss in anterior shoulder instability. Bone Joint J. 2024;106-B(10):1100-1110.
3. Itoi E. “On-track” and “off-track” shoulder lesions. EFORT Open Rev. 2017;2(8):343-351.
4. Shaha JS, et al. Redefining “Critical” Bone Loss in Shoulder Instability: Functional Outcomes Worsen With “Subcritical” Bone Loss. Am J Sports Med. 2015;43(7):1719-1725.

Request a Shoulder Instability Evaluation

Multiple locations across Westchester.