Acromiaclavicular (AC) Joint Injuries

Acromioclavicular joint (ACJ) injuries commonly result from a direct force, generally occurring from a fall onto the tip of the shoulder with the arm adducted.  They comprise 3% to 5% of all shoulder injuries.  Disruption of the acromioclavicular ligaments alone after such trauma may result in inferior subluxation of the ACJ.  Larger forces can lead further to rupture of the coracoclavicular ligaments, resulting in the complete dislocation of the ACJ, with potential long term pain and functional disability.

The treatment for Acromioclavicular joint (ACJ) disruption varies according to the grade of injury. In general, there is a consensus that Types I and II (mild to moderate sprains of the joint) are treated conservatively with analgesia, a short period of support in a sling, followed by early mobilisation.  However, the evidence suggests that Types IV, V and VI where the end of the clavicle is completely dislocated comprise injuries that may have a poorer outcome if conservatively managed and operative intervention may be required.

The ideal treatment of the Type III (where the end of the collarbone sits up significantly) injury remains controversial and practice varies between centres and individuals.  Most Type III injuries are currently treated conservatively.  A series of retrospective studies showed no outcome differences between operative and non-operative groups. Furthermore, the patients treated non-operatively returned to full activity sooner than surgically treated groups.  Exceptions to this include those individuals who perform repetitive or heavy lifting, those who work with their arms overhead, and thin patients who have a prominent ACJ. These patients may benefit from early surgical repair. Surgical repair in my practice involves coracoclavicular ligament reconstruction using a nylon prosthetic ligament called a Surging. In my practice I usually suggest waiting for three months before deciding to operate on grade III injuries as in many instances the pain will have settled by that stage and normal function of the arm returned. If after three months from injury the ACJ dislocation is still troublesome then surgery may be considered.

Operative technique

Under general anaesthesia with the patient in the beach chair position, a vertical skin incision is made from above the clavicle just medial to the ACJ to the level of the coracoid process over the front of the shoulder. The deltoid muscle is split in line with its fibres and the lateral clavicle is exposed.  The outer 5mm to 10mm of clavicle is excised. The base of the coracoid is identified and a curved guide instrument was carefully slid adjacent to and around the bone from medial to lateral to allow the Surgilig to be seated close to the coracoid.  The instrument is then used to feed the Surgilig Length Gauge around the coracoid.  This measuring tape is then looped around the coracoid in the same manner as the proposed ligament, and passed up and behind the lateral end of the clavicle.  The clavicle is reduced to its normal alignment and position and the appropriate length of the Surgilig is measured.

The Surgilig is then ‘daisy chained’ to the Surgilig Length Gauge and passed around the base of the coracoid.  The Surgilig is tensioned to the coracoid using a Loop Tensioner and the free end passed inferiorly around the bulk aspect of the clavicle.  This was then fixed to the front surface of the clavicle with a 3.5mm screw and accompanying washer.  Postoperatively, the arm is supported in a sling for 4 weeks and then mobilised with supervised physiotherapy.

ACJ dislocation is a common injury and, given the number of different surgical procedures that have been described for its treatment, no single technique has been demonstrated to be ideally suited. Although there appears to be consensus that Type IV to VI injuries should be surgically managed, the management of Type III injuries still causes debate, with some centres advocating immediate surgery, whereas others suggest a conservative approach and intervention at a later date should the patient remain symptomatic.  Many surgeons such as myself suggest waiting for a period of three months in the case of a Grade III injury before offering surgery.

The overall success rate in ACJ reconstruction surgery is approximately 90%, as reported in various studies.  In the case of late reconstruction, the success rate has been reported at approximately 78%. The use of the Surgilig in ACJ disruptions has yielded comparable, if not better, overall results compared to the other techniques of early and/or late reconstructions reported in the literature, with comparatively less adverse effects.

AC joint dislocation and disruption of coracoclavicular ligaments

AC joint following surgilig reconstruction

Some patients elect to have the screw removed at least 9 months after surgery as a result of irritation or prominence beneath the skin.

There have been no cases of postoperative infection or re-operations as a result of impingement of the lateral end of the clavicle on the acromion.  None of my patients have reported any untoward reactions to the synthetic materials used for reconstruction.

I have been successful in treating both acute and chronic injuries using the Surgilig, with high patient satisfaction and excellent functional results. So far, there has been sparse evidence on the use and longer-term outcomes of this implant for treatment of ACJ injuries. I have not had any significant complications or adverse reactions outlined in previous studies.  The implant appears inherently strong and allows preservation of the coracoacromial ligament. I conclude that this technique is a safe, simple and reproducible method of reducing and stabilising the acromioclavicular joint.

AC joint dislocation

Reconstructed AC joint