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Open excision of acromioclavicular joint (Mumford procedure)

    Overview

    Learn the Open excision of acromioclavicular joint (Mumford procedure) surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Open excision of acromioclavicular joint (Mumford procedure) surgical procedure.
    This is a useful technique to be able to offer to patients with a acromioclavicular joint pain secondary to degenerative change. Isolated acromioclavicular joint pain is quite common and can vary in severity, from being either a minor inconvenience to interfering significantly with work, sport and leisure activities and in particular sleep.
    The clavicle is one of the last bones to fully ossify in the human skeleton and almost as soon as it has done so there is propensity for it to degenerate at either the medial sternoclavicular joint or more commonly at the lateral acromioclavicular joint. The onset of pain in the acromioclavicular joint can be insidious or maybe as a result of minor trauma such as a grade 1 or a grade 2 sprain, which comes about as a fall directly on to the point of the shoulder or a direct blow to the acromioclavicular joint.
    It has been documented that approximately 30% of the population have an intra-articular disc of soft tissue similar to a knee meniscal cartilage within the acromioclavicular joint. If this were to be damaged, then that can also be a cause of persistent pain and disability.
    Once a diagnosis of acromioclavicular joint pain has been established then simple conservative measures should be recommended in the first instance. If non-operative measures have been exhausted and the patient has persistent pain, then consideration should be given to excision arthroplasty of the acromioclavicular joint with removal of the joint contents and resection of the distal clavicle articular facet. This is also known as the Mumford procedure after an early description published in 1941. The cavity then fills with scar tissue and generally the patient’s symptoms are greatly improved quite quickly. The open technique described here is relatively quick, straightforward and successful.

    Indications

    Indications
    The indication for an open excision of the acromioclavicular joint and distal clavicle is primarily pain. The majority of such patients have degenerative arthritis within this joint but this is also a very common finding in patients who are asymptomatic. It is worth reflecting that the majority of patients over the age of 40 years old will have some radiographic evidence of degeneration of the acromioclavicular joint with joint space narrowing, sclerosis and cyst formation.
    The treating surgeon therefore must be convinced that the acromioclavicular joint is the site of the patient’s symptoms and this is ascertained with careful history, examination and investigation as follows. As always conservative non-operative measures must have been exhausted prior to considering surgical intervention.
    Symptoms & Examination
    Symptoms
    Patients classically present complaining of persistent shoulder pain aggravated by activities. Direct enquiry as to the patient’s occupation and sports and leisure activities is important in helping to understand their requirements and expectations. It should be ascertained as to whether there has been any specific injury to the shoulder resulting in the symptoms with which they present. They will describe pain at the top of the shoulder and may point directly to the distal clavicle and acromioclavicular joint. Activities above head height or across the midline of the body and particularly those requiring repetition are particularly painful. The patient will perhaps describe an increase in discomfort lying directly on that shoulder or loading the acromioclavicular joint in any way.
    Examination
    On clinical examination it is important to assess for symmetry compared to the opposite shoulder. There may be some hypertrophic changes with osteophyte formation at the distal clavicle or even on the superior aspect of the acromial facet of the ACJ. Palpation is important and almost certainly the patient will have pain on palpation over the acromioclavicular joint. Shoulder movements should be assessed with all movements compared with the opposite side. I routinely check passive and active movements of external rotation, forward elevation, abduction and lateral elevation and internal rotation. Assessment of rotator cuff strength should be performed and also assessment of whether the patient has signs of subacromial impingement. Assessing all these movements and clinical signs may well reproduce pain at the top of the shoulder around the acromioclavicular joint. The clinician should then move on to performing specific acromioclavicular joint provocation tests. These tests simply load the acromioclavicular joint and must reproduce the pain at the top of the shoulder to be positive. Such tests include the scarf test with reproduction of pain with simple horizonal adduction of the arm across the patient’s midline mimicking throwing a scarf over the opposite shoulder. This can be performed with the elbow straight. Once this has been performed the thumb can be turned to the floor with further pronation of the forearm and keeping the extended arm across the patient’s midline, then resisted elevation of the hand towards the ceiling can reproduce acromioclavicular joint pain. The is the so called O’Brien’s test for which the differential diagnosis is pathology from the long head of biceps tendon. Acromioclavicular joint pain is classically reproduced with high elevation, the so called high arc and this would be with patient’s elevating in the plane of the scapular, above the horizontal or shoulder height. I will often ask a patient to touch the opposite ear with their arm against the ipsilateral ear and this also should reproduce the pain from the acromioclavicular joint. The ACJ is further loaded with pushing the extended arm into internal rotation around the patient’s back. The final acromioclavicular joint test is distraction by grasping the fingers of each hand in front of the chest and pulling the shoulder blades together. This will further load the acromioclavicular joint and if this is the source, pain will be reproduced. It is important to assess whether there is any instability in the acromioclavicular joint or distal clavicle, as well as assessing the neurovascular status of the upper limb.
    Investigation
    3 view plain x-rays of the shoulder are highly recommended. I ask for a true anterior to posterior (AP) x-ray of the shoulder, as well as lateral outlet view of the subacromial space and an axillary view to further assess the articulation of the distal clavicle with the acromion and importantly to look at whether there is an os acromiale. Whilst varying degrees of degenerative change are commonly seen on plain radiographs, particularly in those patients over the age of 40, it maybe that the acromio-clavicular joint looks entirely normal. This maybe because pain is emanating from a soft tissue injury within the joint or around the capsule and in this case further imaging with ultrasound scan or MRI scan might be useful. CT scan can be useful in looking for occult fractures, not seen on plain radiographs. Ultrasound scanning is useful and this can be used to accurately guide the placement of an intra-articular injection of steroid and local anaesthetic as part of diagnostic and therapeutic treatment of the shoulder pain.
    Alternative Operative Treatment
    Whilst the technique described here is for open surgery, the alternative would be to perform the same procedure as an arthroscopic technique, often combined with subacromial decompression. Arthroscopically the acromioclavicular joint can be accessed from the inferior aspect via the subacromial space to remove the degenerate contents and resect both the articular facets of clavicle and acromion. In younger patients with isolated AC pain, some surgeons advocate isolated arthroscopy of the joint alone without breaching the subacromial space.
    Non-Operative Management
    Once diagnosis has been made of acromioclavicular joint pain then the patient should be counselled as to the pathophysiology. They will have almost certainly ascertained for themselves that certain activity modification is beneficial to their symptoms. Simple measures such as oral analgesic tablets or anti-inflammatory medications taken either as tablet or as a topical application of a gel or cream is very useful and should be tried for several weeks. Avoidance of aggravating activities and alteration of sleep position or sporting activities can also be tried but is often impractical.
    Physiotherapy techniques can be useful but often the patient’s have a full range of motion and good strength and for isolated acromioclavicular joint pain our physiotherapy colleagues often feel they have little further to offer.
    Steroid and local anaesthetic infiltration of the acromioclavicular joint is very useful, not only for therapeutic benefit but also confirming a diagnosis. Injection of local anaesthetic alone can be used for diagnostic purposes and this can be either performed as a blind technique using anatomical landmarks or with guidance from an ultrasound or a fluoroscopy machine. As the acromioclavicular joint is small of low volume, I will tend to use only a maximum 2mls of a mixture of 2% lignocaine and 40mg of steroid, usually depomedrone. If such a local and steroid anaesthetic injection is transiently beneficial then it can be discussed with the patient whether they would consider repeat injection. Often repeat injection does not have a cumulative benefit but if they were given several months of pain relief this maybe worthwhile. With all acromioclavicular joint injections, the patient must be counselled as to the small risk of infection and side effects such as skin blanching or fat necrosis. Skin blanching can be a very real problem for patient’s of pigmented darker skins but can also present as thinned skin with a noticeable dimple in caucasian patients.
    Contraindications
    The patient’s general medical state should be assessed as to whether they are fit enough to undergo general anaesthetic. Patients must be able to comply with a simply post-operative regime and understand that it may take several weeks for them to gain full benefit from surgical intervention. Be careful to assess the skin is in good condition overlying the surgical site prior to embarking on open surgery.

    Setup

    In the semi-sitting or beach chair position the patient is secured with their head on the head-ring of a shoulder specific table attachment. In the absence of implants for this operation intravenous antibiotics are not specifically required. Thromboembolic prophylaxis is provided with intermittent calf compression for the time of the procedure. The operated arm rests at the side of the patient and is held in place with a J-board. As it is not necessary to move the operated arm during the procedure then the shoulder alone can be painted with skin preparation and the shoulder ‘squared off’ with drapes.

    Operation – 1

    AP radiograph showing humeral head (HH), acromion (A) and clavicle (C). The acromioclavicular joint between the acromion and the clavicle shows some narrowing and some superior osteophytes on the distal clavicle. The overall joint space looks reasonably well preserved.

    This coronal section MRI scan shows a high signal within the degenerate acromioclavicular joint (ACJ). The rotator cuff appears intact and certainly the muscle of supraspinatus (SSp) is good. There is an incidental bone island within the humeral head (B). The high signal within the acromioclavicular joint indicates activity within the bone and inflammation which would result in pain.

    This sagittal section MRI scan shows the acromioclavicular articulation with high signal, expanded capsule and irregularity both within the intra-articular soft tissues and on the articular facets of both clavicle (C) and acromion (A). In this section previously noted a bone cyst is not seen within the humeral head (HH).

    This transverse section MRI scan shows a cross-section between the acromion (A) and clavicle (C). Within the acromioclavicular joint there is a high signal further indicating inflammation. On this view it can be seen that the plane of the joint is straight and this will aid with surgical planning

    The patient is positioned in the beach chair position on operating table.This shows the positioning of the patient in the beach chair position. Under general anaesthetic the patient is placed in this position with the head resting on the head-ring of the table (HR). A small sandbag (S) is placed beneath the shoulder blade bringing the shoulder forward. The arm is placed by the side of the patient and held in place using a J-board (J).

    The skin is marked to show the anatomical landmarks of the coracoid process (Co) anteriorly, the clavicle (Cl) and the acromion (A). The proposed surgical incision is seen with the hashed line over the distal clavicle parallel with the acromioclavicular joint.

    The entire shoulder area is prepared with red-staining chlorhexidine solution.

    The superior shoulder area is then ‘squared off’ with appropriate adhesive disposable sterile surgical drapes.

    The surgical site is then injected with local anaesthetic with adrenaline. I use 10mls 0.5% bupivacaine with adrenalin. I instil the acromioclavicular joint cavity and then within the subcutaneous tissues beneath the marked surgical incision. The vasoconstrictor action of the adrenaline helps with intraoperative haemostasis.

    The skin incision (3-4cm) is made over the distal clavicle parallel with the acromioclavicular joint.Either monopolar or bipolar diathermy is used for haemostasis in the cutaneous and subcutaneous tissues.

    Fat and areolar tissue are swept away once through the skin to expose the superior capsule of the acromioclavicular joint. Insertion of a small West’s self-retaining retractor (W) exposes the superior capsule of the ACJ and the joint can be palpated.

    The acromioclavicular joint can be identified by piercing the superior capsule with a hypodermic needle.This is important to identify the joint. The base of the coracoid process is deep to this and medial to that is the brachial plexus and large vessels.

    Using cutting diathermy the superior AC joint capsule is incised across the joint perpendicular to the skin incision.
    This subperiosteal plane is then extended medially across the distal clavicle in the line of the bone.

    Using either a cutting diathermy probe or a no 15 scalpel blade, the AC joint capsule and confluent clavicular periosteum are elevated as two thick flaps of tissue both anteriorly and posteriorly.
    In this image the anterior joint capsule is being held in the forceps as it is elevated away from the acromion and distal clavicle. Reflect just enough to expose the front edge of the clavicle.

    Mobilisation of posterior capsuleHere the posterior flap of capsule and periosteum is being grasped with the forceps. Again just peel back enough periosteum to expose the posterior surface of the clavicle. Insertion of a second West’s self-retaining retractor is useful at this stage.

    Once the acromioclavicular joint cavity is exposed then degenerate or torn fibrotic soft tissue can be identified within the joint.

    Using sharp dissection the degenerate soft tissue content of the acromioclavicular joint is removed.

    Once the joint cavity is cleared of soft tissue, a small Homan retractor (H) is placed over the front of the distal clavicle. Do not dive the retractor too deep anteriorly as the brachial plexus and large vessels run medially beneath the coracoid process.

    Place a small Homan’s retractor to expose the anterior distal clavicle.

    A second small Homan retractor can is placed in behind the distal clavicle retracting the posterior flap of periosteum and joint capsule. This further exposes the extent of the distal clavicle articular facet.

    With both small Homan retractors in position a periosteal elevator (P) is used to further expose the superior aspect of the clavicle.

    Once the lateral 1cm of the clavicle is exposed take an oscillating saw with blade 1-2 cms wide for excision of the joint.

    Use the oscillating saw to resect between 0.5 and 1 cm of distal clavicle.
    Soft tissues are protected using the self-retaining and the small Homan retractors. Take care when approaching the second and deep cortex. Plunging the saw deep into the wound threatens the coracoid process and the important neurovascular structures of the brachial plexus and subclavian vessels.

    The periosteal elevator is used to mobilise the resected distal clavicle which is then removed with a bone nibbler.

    A bone nibbler (N) is used to remove the resected bone fragment of the distal clavicle.

    Operation – 2

    The irregular articular surface of the articular facet of the distal clavicle of the acromioclavicular joint can be seen.

    It can be seen that the width of resected bone from the distal clavicle is less than 1cm. It is not necessary to excise more than 1cm to gain good clearance for the resected ACJ. The strong coracoclavicular ligaments (conoid & trapezoid) attach to the inferior surface of the distal clavicle and care must be taken not to damage them. Fortunately they insert at least 2 cm medial to the clavicle articular facet.

    Using an index finger the extent of the clearance of the excision arthroplasty can be assessed by palpation within the joint cavity.

    Sharp edges of the distal clavicle at the site of the resection should be smoothed off by chamfering the bone using a bone nibbler.

    The joint cavity is irrigated with saline lavage.

    Once it is confirmed that a clear excision arthroplasty has been achieved then identify the anterior and posterior periosteal and capsule flaps of soft tissue to be repaired.

    The anterior and posterior periosteal and joint capsule flaps are then repaired with interrupted no. 1 vicryl stitches.

    Interrupted stitches are used to repair the superior joint capsule and clavicle periosteum.

    Closure of fascia and fat, followed by skinThe superficial fascia and fat are closed with continuous 2/0 vicryl suture.

    At this stage the excision arthroplasty joint cavity is instilled with further local anaesthetic for post-operative analgesia. Here, using a hypodermic syringe and needle the joint cavity is injected with 10ml 0.5% plain levobupivacaine.

    The skin is then closed using a running subcuticular monocryl suture.

    Final view of closed surgical wound.

    The repaired skin is further protected using paper steri-strips.

    A simple adhesive waterproof dressing is then applied to cover the surgical site.

    Post Operative

    This operation does not require immobilisation in a sling. Occasionally the patient has pain which requires a sling application simply for analgesia. Once the patient is awake and mobilised, they can be discharged home as a day case procedure. They are encouraged to mobilise elbow, wrist and hand and are allowed underarm hygiene. The adhesive dressing should be left in place until review at two weeks. Shoulder movements are allowed within the limits of comfort, limiting excessive movement above shoulder height or across the midline. Once the wound has been reviewed at two weeks and steri strips removed with trimming of the ends of the absorbable sutures, then physiotherapy rehabilitation can start to regain active full movement. Once full movement has been regained then strengthening exercises can begin at approximately four weeks.

    Recommended Reading

    Acromioclavicular dislocation. A new operative treatment.
    EB Mumford. J Bone Joint Surg [Am] 1941;23(4):799-801
    The author has ended up with his name attached to the excision arthroplasty operation widely used for arthritic conditions when actually his original description concerned dislocations
    The treatment of complete dislocation of the outer end of the clavicle: A hitherto undescribed operation.
    FB Gurd. Ann Surg 1941; 113:1094-1097

    Osteoarthritis of the acromioclavicular joint.
    JN Worcester, DP Green. Clin Orthopaedic 1968;58:69-73

    The degeneration of the acromioclavicular joint. Treatment by resection of the distal clavicle.
    DW Grimes, RW Garner. Orthop Rev 1980;9:41-44
    Early reports of success with excision arthroplasty
    Lateral clavicular resection in painful acromioclavicular joint conditions.
    J Sterup, HC Thyregod, JS Jensen. Adv Orthop Surg 1988:218-220

    Arthroscopic acromioclavicular joint debridement and distal clavicle resection.
    EL Flatow, LU Bigliani. Tech Orthop 1991;1:240-247
    The advent of shoulder arthroscopy led to reports of the minimally invasive technique
    Arthroscopic versus open distal clavicle excision: comparative results at six months and one year from a randomized prospective clinical trial.
    BA Freedman, MA Javernick, FP O’Brien, AE Ross, WC Doukas. J Shoulder and Elbow Surgery. Volume 16, 4, July-Aug 2007:413-418
    “Arthroscopic and open distal clavicle excisions both provide significant pain reduction at 1 year. Both are effective surgeries for the treatment of refractory acromioclavicular joint pain. The ability to diagnose and treat subtle concomitant shoulder pathology is a unique advantage of the arthroscopic approach”
    Managing Acromio-Clavicular joint pain: a scoping review.
    S Chaudary, L Bavan, N Rupani, K Mouyis, R Kulkarni, A Rangan, J Rees. Shoulder & Elbow 2018;10(1):4-14
    Comprehensive review in British journal reporting the published literature on ACJ pain with interesting conclusions …

    Reference

    • orthoracle.com

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