Due to a scarcity of bony restraints and minimal articular contact the shoulder joint has the greatest range of motion of any joint in the body. It relies on soft-tissue restraints for stability, including the capsule, musculature and ligaments. Because of this, the shoulder joint is at high risk for dislocation. There are many shoulder dislocation reduction techniques. Many of these have been described in the literature, however, there is lack of comparative studies on the various techniques. It is essential that there be thorough understanding of anatomy, classification of the dislocation, type of reduction maneuver and different anesthetic technique for successful management of this injury.
The shoulder joint is held in a reduced position through both static and dynamic stabilizers. Static stabilizers include the glenoid fossa, labrum, capsule and glenohumeral ligaments. They work by maintaining the continuity of the joint through reinforcing support at end ranges of motion. For example, the labrum increases shoulder stability by contributing 50 per cent of the glenoid cavity depth and increasing the total surface area. The glenohumeral ligaments resist translation. Dynamic stabilizers include the deltoid, biceps, rotator cuff and scapular stabilizing muscles. They function via the neuromuscular system by actively stabilizing the moving joint at mid ranges of motion. For example, the rotator cuff provides a dynamic compression of the humeral head into the fossa of the shoulder joint. The trapezius, rhomboids, latissimus dorsi, serratus anterior and levator scapulae muscles actively stabilize the scapula to allow for increased stability. Shoulder dislocations are classified as either traumatic or atraumatic. They are further classified by the direction of dislocation either anterior, posterior or inferior. Anterior shoulder dislocation is the most common at ninety seven percent.
Despite that there are multiple reduction maneuvers available some general principles apply to acute management of shoulder dislocations. A dislocation should be reduced as quickly as possible to avoid muscular spasms and neurovascular compromise and it’s important that all of this should be done in a gentle and technically sound closed reduction process. If the reduction is tended to quickly before muscular spasm sets in, often it can be done without local pain medication. Anesthesia may be required and it is recommended that intra-articular block be used first, while reserving sedation for the more difficult cases. Like mentioned previously, multiple reduction techniques exist. For anterior dislocations popular reduction methods include: Hippocrates, Traction-countertraction, Chair, Kocher, Stimpson, Milch, External Rotation, Spaso, Eskimo, Scapular Manipulation and FARES (Fast, Reliable and Safe). Posterior dislocations are less common occurring only three percent of the time and are often more difficult to diagnose. Closed reductions are often difficult and may require at least two operators and sedation. Inferior shoulder dislocations are even more rare, occurring less than one percent of all dislocations. Two different reduction methods are used in inferior dislocation management known as Traction-Countertraction and Two-step.
Only a few studies have looked at and compared different methods of closed reduction. In a study of 111 patients, the Milch and Kocher techniques were compared. They found no difference between the two in success rate but the Milch technique was found to be more successful in patients over forty years of age when performed within a timeframe of four hours of dislocation. In a randomized study with patients who suffered anterior dislocation were treated with either the Stimson or Milch technique. With the Milch technique success rate was 82 per cent on first reduction compared to only 28 per cent for the Stimson technique. Another randomized control trial of 154 patients with anterior dislocation demonstrated that the FARES method was more successful, quicker and less painful than the Kocher and Hippocrates techniques. After successful reduction, rehabilitation usually occurs to maximize range of motion and to regain stability. There is usually a minimum period of immobilization lasting three to four weeks. Gradual return to activity will be achieved after this.
The authors of this review conclude that while there are many methods for management of acute dislocation, the orthopedic surgeon must be well versed in different techniques to best decide the appropriate approach for each individual patient.