Treatment of The Posterior Unstable Shoulder

Abstract

Background: It is estimated that approximately 5% of glenohumeral instabilities are posterior. There are a number of controversies regarding therapeutic approaches for these patients.

Methods: We analyse the main surgery alternatives for the treatment of the posterior shoulder instability. We did a research of the publications related with posterior glenohumeral instability.

Results: There are conservative and surgical treatment options. Conservative treatment has positive results in most patients, with around 65 to 80% of cases showing recurrent posterior dislocation. There are multiple surgical techniques, both open and arthroscopic, for the treatment of posterior glenohumeral instability. There are procedures that aim to repair bone defects and others that aim to repair soft tissues and capsulolabral injuries. The treatment should be planned according to each case on an individual basis according to the patient characteristics and the injury type. Surgical treatment is indicated in patients with functional limitations arising from instability and/or pain that have not improved with rehabilitation treatment. The indications for arthroscopic treatment are recurrent posterior subluxation caused by injury of the labrum or the capsulolabral complex; recurrent posterior subluxation caused by capsuloligamentous laxity or capsular redundancy; and multidirectional instability with posterior instability as a primary component. Arthroscopic assessment will help identify potential injuries associated with posterior instability such as bone lesions or defects and lesions or defects of soft tissues. The main indications for open surgery would be in cases of Hill Sachs lesions or broad reverse Bankart lesions not accessible by arthroscopy. We indicated non-anatomical techniques (McLaughlin or its modifications) for reverse Hill-Sachs lesions with impairment of the articular surface between 20% and 50%. Disimpaction of the fracture and placement of bone graft (allograft or autograft) is a suitable treatment for acute lesions that do not exceed 50% of the articular surface and with articular cartilage in good condition. Reconstruction with allograft may be useful in lesions affecting up to 50% of the humeral surface and should be considered when there is a situation of non-viable cartilage at the fracture site. For defects greater than 50% of the articular surface or in the case of dislocations over 6 months in duration where there is poor bone quality, some authors advocate substitution techniques as a treatment of choice. The main techniques for treating glenoid bone defects are posterior bone block and posterior opening osteotomy of the glenoid.

Conclusions: The treatment of the posterior glenohumeral instability has to be individualized based on the patient´s injuries, medical history, clinical exam and goals. The most important complications in the treatment of posterior glenohumeral instability are recurrent instability, avascular necrosis and osteoarthritis.

Keywords: Glenohumeral instability; Instability; Posterior instability; Shoulder; Shoulder arthroscopic; Shoulder surgery.

Fig. (1)

Reverse Hill-Sachs lesions.

Fig. (2)

The transfer of the subscapularis tendon insertion and its suturing at the site of the reverse Hill-Sachs lesion.

Fig. (3)

The transfer of the subscapularis tendon with the lesser tuberosity.

Fig. (4)

Reconstruction with allograft.

Fig. (5)

Posterior bone block. The autograft is obtained from the iliac crest.

Fig. (6)

The arm is placed in a traction device at 45° abduction and 20° shoulder flexion.

Fig. (7)

Posterosuperior portal and the portal 7.

Fig. (8)

The choice of one or another portal is defined according to the best direction obtained with the spinal needle for subsequent implant placement.

Fig. (9A,B)

Kim lesion, lesion of the posteroinferior labrum.

Fig. (10A,B)

The bone bed must be decorticated with manual scraping or with an arthroscopic shaver.

Fig. (11A,B)

The drill guide of the implant of the first anchor is placed at approximately 7 o’clock.

Fig. (12A,B)

The guide and the implant-inserting device are removed, and the implant is sutured in place.

Fig. (13A,B)

Recover of the suture for other posterior cannulated.

Fig. (14)

We set the stitch at approximately 6 o’clock whith 45° ACCU-PASS type clamps and we recover the carrier thread of the suture through the other portal.

Fig. (15)

The two threads of the anchors are left in the same cannula.

Fig. (16A,B)

The first suture is knotted.

Fig. (17A,B)

We usually use four anchors placed at approximately 6:30, 7:30, 8:30, and 9:30.

Fig. (18A,B)

We perform plication stitches by combining the use of anchors (hypoplastic or damaged labrum) with sutures without anchors when there is a labrum that has good morphological consistency.