Acromiocavicular Injuries

Acromio-clavicular injuries commonly result from a fall onto the point of the shoulder which produces a downward force on the acromion and comprise 3-5% of all shoulder girdle injuries (1).
Such trauma may tear the acromio-clavicular ligaments as well as result in apparent superior subluxation of the clavicle (in-fact downwards displacement of the acromion).
The forces from the fall can lead to rupture of the coracoclavicular ligaments leading to complete dislocation of the joint. The latter injuries may be classified by severity with a view to guiding treatment, both operative and non-operative.
The original classification of ACJ injury severity proposed by Tossy et al(3) comprised grades I-III, determined by the individual structures damaged; Rockwood expanded on the latter by further sub-classifying Grade III injuries into types III-VI(2).
This classification can be applied to both acute dislocations and old and chronically unreduced ruptures.

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There is no doubt that the vast majority of patients do extremely well with non-operative treatment, this is particularly true for the common type I & II injuries.
In the simpler displaced ruptures (type II & III) treated conservatively, the subject is left with a visible cosmetic deformity of a prominent lateral clavicle & the shoulder hangs slightly lower than the other side, but in most cases, shoulder function after full recovery is very good.
For some however, shoulder function can be severely affected. The unstable joint produces symptoms of pain, fatigue and the inability to lift heavier objects with that limb. Neck pain can develop. Occasionally traction on the brachial plexus causes neuralgic arm pain as well.
Treatment of Rockwood Type III ACJ injuries has been a contentious issue and practice varies between different centres and individuals.
A common practice has been for type III injuries to be treated conservatively in the first instance with late reconstruction if required (3).
Conversely, there is a general consensus that acute type IV-VI injuries have a poor outcome if managed conservatively and open reduction and internal fixation are required.
For these and those with significant symptoms following failed conservative treatment of type III injuries, a number of surgical solutions have been proposed.

Operative repair of the disrupted ACJ alone, appears to give little benefit when compared to conservative treatment.

However, various methods of stabilising the clavicle by repairing or reconstructing the strong ruptured Coraco-Clavicular ligaments connecting the clavicle to the Coracoid process, and often combined with excision of the lateral end of the clavicle, have been described over very many years, although complications of implant breakage or loosening, bone fracture, graft failure or need to remove the implant meant that surgery did not always provide a reliable solution.

  • separation. J Bone

    Examples of operative techniques for ACJ reduction and fixation:

  • Internal fixation with Kirschner-wiresACJ reduction, fixation achieved by drilling steel Kirshner wires across the acromion, the AC Joint and into the lateral end of the clavicle.

    Unfortunately the reduction of the ACJ is often lost soon after the wires are removed 6-8 weeks post-operatively

    Worse this carries the risk of wire loosening and migration, this can be very dangerous.

  • Bosworth screw fixation(3)ACJ reduction, fixation achieved by drilling a Bosworth screw through the clavicle, then inferiorly into base of the coracoid process, followed by coraco-clavicular ligament repair with sutures. Aftercare includes gentle mobilisation after 1 week and delaying more forceful mobilisation and lifting until after screw removal at 8 weeks.

    Again there is risk of migration of the screw, and frequent loosening of the screw with erosion of bone around the implant.

    This has also led to further fracture of the clavicle at the position of the screw.

    There is the necessity for a second procedure to remove the screw.

  • Mumford- Distal clavicular excisionIndicated for chronic, symptomatic, type II subluxations. The acromion is sutured to raw end of the clavicle followed by prompt mobilisation after 1 week.

    Variable results and does not address symptoms arising from clavicular instability

  • Weaver-Dunn -Distal clavicular excision with coraco-clavicular ligament reconstruction(4)
    Coraco-acromial ligament is freed from the acromion and sutured to the remaining end of the clavicle through its intramedullary canal to achieve reduction. Patients may mobilise gently after one week in a sling, but delay more forceful mobilisation and lifting until after 6-8 weeks.This procedure relies on a viable coraco-acromial ligament and can fail to stabilise the clavicle sufficiently, especially for the higher grade injuries (for these it is best combined with some form of coraco-clavicular ligament reconstruction or fixation).

    Unavoidably disrupts the coraco-acromial arch.

  • Coraco-clavicular ligament reconstruction using various soft tissue autografts or allografts
    free tendon grafts, e.g. fascial grafts; long head of biceps tendon, etcThese can require harvesting of either local or separate area tissue and the consequent loss of that tissue and either a bigger or a second operation site & wound.
  • Coraco-clavicular ligament reconstruction with prosthetic ligamentThe Nottingham Surgilig:

    The implant is made from polyester with braiding technology originally developed to produce the ABC, the ARD and the Soffix ligaments, which have been extensively used in the knee over many years.

    Loops are woven into each end of the grafts, which come in a range of lengths. The prosthetic ligament is looped around the base of the coracoid process, then threaded through itself to provide a broad based fixation which will not erode or cut through the bone. A firm, smaller loop, at the clavicular end allowing secure screw fixation to the clavicle. The graft is threaded posteriorly around the circumference of the clavicle, thus allowing the natural rotation (45?) of the clavicle to occur without risk of erosion or fracture (as can occur with many other implants).

    Over a period of time, fibrous ingrowth occurs, establishing the formation of a “neo-ligament” with host tissue, but retaining the excellent implant strength.

    The strength of the construct exceeds that of the natural ligaments thus allowing very early mobilisation, and early return to sporting and strenuous activities.

    For those patients who have persistent symptoms following conservative treatment for AC dislocations types I –III, early operative intervention is advocated by many surgeons, especially for manual workers and athletes.

    Results of early repair have been reported to be superior to those carried out late 10.

    Drawbacks of earlier techniques such as the Weaver-Dunn (otherwise successful for relatively stable injuries) include the delay in recovery to full function and performing resistive shoulder exercises until soft tissue healing is sufficiently advanced at 10-12 weeks; as well as the need for further fixation with higher grade injuries.

    Conversely, using an implant such as the Nottingham Surgilig, patients are able to resume normal activities from 2 weeks without the need for medium term protection.

    References

    1. Rockwood Jr CA, Young DC. Disorders of the Acromioclavicular Joint. In Rockwood Jr CA, Matsen III FA (eds). The Shoulder. Philadelphia: WB Saunders, 1990: 413-468

    2. Rockwood Jr CA. Injuries to the Acromioclavicular Joint. In Rockwood Jr CA, Green DP (eds). Fractures in Adults. Philadelphia: JB Lippincott, 1984: 860-910

    3. Tossy JD, Mead NC, Sigmond HM. Acromio-claviculare separations: useful and practical classification for treatment. Clinical Orthopaedics and Related Research 1963; 28: 111

    4. Weaver JK, Dunn HK. Treatment of acromioclavicular injuries, especially complete acromioclavicular

  • Joint Surg Am. 1972 ; 54A:1187-94