Septic Arthritis About the Shoulder: Glenohumeral, Acromioclavicular, and Sternoclavicular Joints

The Problem

Septic arthritis of the native shoulder is an uncommon orthopaedic infection, yet prompt diagnosis and treatment is essential for prevention of potential long-term morbidity. The glenohumeral (GH), acromioclavicular (AC), and sternoclavicular (SC) joints are all subject to septic arthritis and each must be treated quickly to preserve the function of the shoulder girdle and prevent spread of infection. Furthermore, the joints of the shoulder girdle are sometimes subject to atypical bacterial infections that are commonly missed.

As with any other septic joint, targeted antibiotic coverage based on aspirate cultures is essential, and treatment routinely requires thorough irrigation and debridement. Without proper treatment, joint destruction and loss of function is common. Despite adequate surgical treatment and appropriate antibiotic coverage, a relatively high rate of reoperation, morbidity, and mortality has been associated with septic arthritis of the shoulder. It is therefore incumbent on the surgeon to make an accurate diagnosis and quickly treat joint infections about the shoulder.

Clinical Presentation

In general, septic arthritis of the GH joint is more common in the elderly and immune compromised, while AC and SC joint infections can be seen in younger populations, often those with a history of intravenous drug use (IVDU). Patients with involvement of any of the joints about the shoulder may present with diffuse pain of the shoulder or chest that localizes to the affected joint without antecedent trauma.

The presence of pain or effusion may limit range of motion, and palpation may elicit tenderness. Patients may note swelling, redness, and warmth over the affected joint as well. Constitutional symptoms are present in many patients. Fever (> 38° C) was present in 65 percent of patients with an SC joint infection as reported in one study. The duration of symptoms varies, but most patients present in the acute or sub-acute phase. Symptoms may be present for up to a month prior to initial presentation.

Whether due to malignancy, human immunodeficiency virus (HIV), IVDU, end stage renal disease (ESRD), chronic medication use (i.e. chemotherapy) or diabetes, a majority of patients with septic arthritis of the shoulder are either immunocompromised or have chronic medical comorbidities. In addition, many patients may report a history of injections, either of corticosteroid, needle acupuncture, or local anesthesia. Some patients may describe a prior illness, recent intravenous drug use, preceding therapeutic injection, or demonstrate a history of recently positive blood cultures as well.

Septic arthritis of the SC joint may be more difficult to diagnose as the onset may be more insidious and symptoms may be more non-specific. Therefore, a relatively high index of suspicion should be key in patients presenting with risk factors for these infections. In addition, all patients being assessed for SC joint infection should also be assessed for empyema, mediastinitis, osteomyelitis, or possible chest wall compressive abscesses or phlegmon.

On physical exam, patients typically guard the affected shoulder. AC and SC joints may demonstrate an effusion or local swelling with associated erythema, though this may vary with body habitus. The GH joint may have a subtle effusion, but due to the overlying soft tissue bulk, local swelling and erythema will likely be less obvious than those infections involving the AC or SC joints. Palpation may elicit pain. Local warmth may also be present. Active and passive range of motion may be limited by pain in all three joints, although we find shoulder motion to be more preserved with AC or SC joint infections. Provocative testing, such as cross-arm abduction, may exacerbate pain in the AC or SC joints.

Diagnostic Workup

Diagnostic workup begins with a high index of suspicion, and should include standard and advanced imaging techniques, laboratory studies, and diagnostic aspirations. In the acute phase, changes on routine radiographs will likely not be present but should still be obtained to assess for possible bony destruction and for comparison to future films. For the GH joint, standard anteroposterior (AP), axillary, and scapular-Y views are sufficient. Additional views including the Zanca view (10-15 degree cephalic tilt) and the Serendipity view (40 degrees cephalic tilt) help visualize the AC and SC joints, respectively.

While acute radiographic changes are rare, advanced septic arthritis may demonstrate cartilage destruction, indicated by joint-space narrowing, marginal erosions, and periostitis if osteomyelitis is present (Figure 1). Ultrasound can reveal the presence of an effusion or synovial hypertrophy, and it may be used during joint aspiration to increase the accuracy of the technique. Magnetic resonance imaging (MRI) (Figure 2) can be useful in cases where the clinical presentation is unclear. Joint effusions, soft tissue changes, abscesses, and bone involvement are all visualized on MRI and can help guide decision-making, though its use may be limited when implants are present.

Figure 1.

Figure 2.

Laboratory testing and synovial fluid analysis are essential to establishing a diagnosis of septic arthritis. Complete blood count (CBC), comprehensive metabolic panel (CMP), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) should all be drawn. Blood cultures and gram stain should also be sent to assess for bacteremia. Leukocytosis may or may not be present, and is likely to be affected by the immune status of the host and the patient’s ability to mount a response. A CMP is useful to assess renal and hepatic function with respect to overall health and future antibiotic administration.

While basic bloodwork are important diagnostic tools, joint aspiration with subsequent synovial fluid analysis is of the utmost importance. The results of the aspiration will ultimately assist in guiding treatment and aid in antibiotic selection. Many patients with pyogenic arthritis will have over 100,000 white blood cells when analysis of joint fluid is performed.

In a series of 46 patients with GH septic arthritis, Abdel et al. reported an average cell count of 110,998 and a mean differential of 87% polymorphonuclear cells, but only 16% of gram stains identified an organism. Of note, one patient’s mean cell count was 572, but he was severely immunocompromised and was presumed incapable of mounting an immune response. Therefore, while the mean cell count and differential are on par with numbers expected of a native septic joint, aspiration results in immunocompromised individuals must be taken in the context of the clinical presentation.

Pre-operative and intra-operative cultures provide vital information for future long-term antibiotic management. Unfortunately, these cultures do not always yield information, as some studies have shown that pre-operative aspirate cultures and intra-operative cultures identify a causative organism only 77% and 82% of the time, respectively. In these cases, empiric treatment is necessary and consultation with an infectious disease specialist is recommended.

Non–Operative Management

In our experience, all cases of septic arthritis warrant an infectious disease consultation to assist with antibiotic selection and duration of treatment. Unlike the emergent operative interventions required to adequately treat septic arthritis of the native knee or hip, septic arthritis of the shoulder joints has, in some reports, been effectively treated conservatively with long-term intravenous and oral antibiotics alone. Other reports have also indicated acceptable results with serial joint aspirations in concert with antibiotics.

Non-operative treatments have been successfully attempted with the SC and AC joints, while surgical management is typically the standard for GH joint infections. Withholding antibiotics prior to aspiration will help maximize culture results, thereby providing the necessary information for tailored antibiotic therapy. Proper culture data will maximize conservative treatment. Therefore, if adequate cultures are obtained and noticeable clinical improvement is demonstrated on initial broad-spectrum antibiotics, conservative treatment may be indicated for septic arthritis of the SC or AC joints.

Conversely, conservative treatment of a septic GH joint appears to be less effective. As a larger joint with greater intra-capsular volume, antibiotic therapy with or without serial aspirations is less effective as bacterial load and antibiotic penetration are too great and too little, respectively. While scant literature exists to prove superiority of operative treatment over conservative, one study indicated that parenteral antibiotics alone resulted in recurrent infection by the same pathogen in one patient.

Empiric antibiotics should target Staphylococcus aureus, including methicillin-resistant strains, as it is the most common causative agent. Escherichia coli, Pseudomonas aeruginosa (especially in those with IVDU), Salmonella spp., Streptococcus spp., and Gram-negative bacilli (Klebsiella pneumonia, Proteus mirabilis and non-enterococcal bacilli) have also been implicated in septic arthritis of the shoulder and should be covered with empiric therapy as well.

Indications for Surgery

In our experience, operative management is indicated when the GH joint is involved. Operative management of the AC or SC joint is indicated if non-operative management fails to provide rapid clinical improvement. In addition, patients that present with advanced disease, such as those with associated mediastinitis, empyema, or abscess formation are best managed via an operative, multidisciplinary approach, making sure a thoracic surgeon is available.

Surgical Technique

Operative treatment of septic arthritis of the shoulder can be performed open or arthroscopically, though typically the latter is performed only for GH or AC involvement. For either method, similar equipment should be on hand for a formal irrigation and debridement. At least nine liters of sterile saline, sterile culture swabs, and specimen containers and a basic orthopaedic tray with self-retainers, curettes, and rongeurs should be available. When performing arthroscopic irrigation and debridement, an arthroscopic shaver, burr, and electrocautery unit should be available as well.

We typically place patients in the beach chair position as it allows easy conversion from arthroscopic to open debridement. For arthroscopic treatment, we typically place the positioner in a more vertical orientation, as opposed to approximately 30 degrees of bed flexion used for open techniques.

Alternatively, the patient may be positioned supine with two folded towels or a sandbag placed between the scapulae. Supine positioning may allow for better exposure of the SC joint. Draping techniques should provide generous exposure to all joints of the shoulder girdle. Pre-operative antibiotics are held until adequate cultures and synovial samples are obtained, and we always begin by performing an arthrocentesis, if possible, to obtain fluid samples.

If cultures cannot be obtained before making an incision, antibiotics should be held until the joint is entered and cultures can be obtained. At the end of the case, we recommend placement of a small drain connected to self-suction and typically leaving this in place for 24-48 hours for adequate post-operative drainage.

We prefer arthroscopic treatment as the treatment of choice in those patients with GH pyogenic arthritis as it is minimally invasive, allows a thorough examination of the joint, and unlimited range of motion post-operatively.

The procedure begins with proper identification of bony landmarks, including the posterolateral and anterolateral corners of the acromion, the clavicle and AC joints, and the coracoid process. We do not distend the joint as an effusion typically gives adequate distention. The standard posterior portal is made approximately two fingerbreadths distal and one medial to the posterolateral corner of the acromion. The arthroscope is then introduced into the GH joint. Using a spinal needle for localization, an anterior portal is then created high in the rotator interval and a diagnostic arthroscopy is begun taking care to critically examine the joint.

We feel that arthroscopic management allows for a more thorough examination of the glenoid and humeral articular surfaces and allows a complete assessment of the articular side of the rotator cuff. Any fibrinous debris or necrotic or inflamed tissue is debrided gently with a 4.5mm arthroscopic shaver. Synovial samples can be taken and sent for appropriate studies. We then place the arthroscope into the subacromial space through the posterior portal. A standard lateral portal is then made after needle localization. Any patient with a full thickness rotator cuff tear in the setting of pyogenic arthritis demands a formal debridement and bursectomy of the subacromial space as well. Otherwise, we feel that a simple irrigation of the subacromial space is adequate in the setting of a patient with an intact rotator cuff.

Open surgical treatment of the GH joint can be accomplished through one of several approaches, though the deltopectoral or lateral approaches are the most common and useful. The deltopectoral approach is our approach of choice, and begins with a vertical incision along the axillary fold. The deltopectoral interval is established by defining and retracting the cephalic vein, which runs between the medial border of the anterior deltoid and the lateral border of the pectoralis major. We prefer to take the vein laterally to preserve feeding branches to the deltoid. The clavipectoral fascia is then exposed, with the conjoined tendon medially and the subscapularis muscle overlying the anterior capsule. A small arthrotomy can be made superior to the rolled edge of the subscapularis, which may need to be partially released superiorly, to improve access to the joint.

Alternatively, a lateral approach can be used. A vertical incision is made over the lateral deltoid, no further than 5-7 cm distal to the tip of the acromion to protect the axillary nerve. The deltoid is split in line with its fibers to expose the underlying bursa and rotator cuff. Access to the joint must go through the rotator cuff, which requires repair after debridement. Considering the population in question, a majority of elderly patients have pre-existing asymptomatic rotator cuff tears, which would aid in access to the joint and may benefit from gentle debridement. Non-braided, monofilament sutures should be used for deep closure and nylon sutures are recommended for the skin. An intra-articular drain may be placed to remove excess fluid, though there is no known evidence in the literature to support or contradict its use.

The AC joint can be approached either open or arthroscopically. For an open approach, a 2-4 cm vertical skin incision is centered over and parallel to the AC joint. The capsule is essentially subcutaneous, with muscular insertions from the deltoid, pectoralis major, and trapezius surrounding the joint. We then incise the capsule in line with the skin incision and debride and excise the fibrocartilagenous disk and any non-viable or infected tissue. A distal clavicle resection is then performed using either an oscillating saw or osteotome, taking care not to violate the posterior capsule. The AC joint can also be approached via the subacromial space arthroscopically, but given the ease of the open approach, this is not recommended unless the infection is suspected in the surrounding soft tissues as well.

An open approach is favored in cases of SC joint septic arthritis. The patient is placed supine on the operating table with 2-4 towels placed between the scapulae. A 3-4 cm skin incision following Langer’s lines (a necklace pattern) centered over the SC joint will expose the underlying platysma muscle. The platysma is incised in line with the skin incision to expose the joint capsule and sternal head of the sternocleidomastoid muscle. The capsule is incised vertically, taking care to preserve the sternal attachment of the sternocleidomastoid. Any infected tissue, including the fibrocartilaginous disk is thoroughly debrided and excised.

If there is concomitant medial clavicle osteomyelitis, we favor a resection arthroplasty of the SC joint over simple irrigation and debridement. A similar incision is utilized and the clavicular head of the sternocleidomastoid and medial clavicular origin of the pectoralis major are subperiosteally dissected. To prevent recurrent instability, the medial clavicle should be resected up to 1.5 cms and this should be done obliquely from superolateral to inferomedial, preserving the costoclavicular ligament. Preserving this ligament is critical, as it is a very important secondary restraint to translation when the SC capsule is disrupted.

The osteotomy may be done with an oscillating saw, but extreme care is needed not to violate the posterior capsule during sawing or removal of the medial piece. After the osteotomy is performed, if needed, the remnant SC ligament can be re-attached, similar to the method described by Chun, et al. The ligament is passed through the medullary canal of the remaining clavicle using non-braided sutures passed through two drill holes, approximately 1 cm lateral to the resected medial clavicle. We strongly recommend having a cardiothoracic surgeon available if bony resection of the medial clavicle is planned.

Pearls and Pitfalls of Technique

Pearls

• Obtain sterile intra-operative cultures prior to irrigation and debridement and antibiotic administration (all techniques).

• If choosing an arthroscopic form of debridement, a thorough assessment should be performed and any necrotic tissue should be removed.

• Open treatment of AC or SC joint provides optimal exposure however great care should be taken to preserve capsular attachments and prevent iatrogenic instability.

• Try to preserve the sternal attachment of the SC ligament for reattachment during a SC joint resection.

• Have a cardiothoracic surgeon available for any open SC joint debridement.

Pitfalls

• Incomplete excision all infected or non-viable tissue or bone (all techniques).

• Failure to appropriately debride the subacromial space in patients with GH septic arthritis and concomitant rotator cuff tear.

• Resection of posterior capsule of the AC joint during debridement or distal clavicle excision.

• Failure to recognize proximity of vital structures during approach to the SC joint.

Potential Complications

There are several potential complications that may develop as a result of septic arthritis of the shoulder. Joint stiffness is the most common complication, but chondrolysis, osteomyelitis, mediastinitis, empyema, phlegmon, avascular necrosis, secondary osteoarthritis, and ankylosis are also potential points of concern, especially given the proximity of the SC joint to vital structures. Furthermore, as many as one in three patients may require repeat operations for recalcitrant infections. Most of the reported complications of septic arthritis of the shoulder are case reports, and there is scant literature describing the incidence of complications after such an infection.

Post–operative Rehabilitation

Excluding open approaches to the GH joint or reconstruction of the SC joint, prolonged immobilization of the shoulder is not indicated. Early range of motion is recommended given the concern for post-operative arthrofibrosis. A sling may be provided for comfort in the initial post-operative period, but should be quickly discarded.

For open approaches, range of motion limitations will include those that may compromise any repair performed during the surgery. If the subscapularis was released during a deltopectoral approach, limitations in external rotation, extension, and active internal rotation should be undertaken to preserve the integrity of the subscapularis repair and these limitations should be set forth depending on intra-operative assessment of repair stability.

No restrictions are needed for any AC or SC joint debridements or excisions unless there is a ligamentous concern addressed intra-operatively. If the ligament is reattached during an SC joint resection, we recommend placing the patient in a sling for 2-3 weeks with pendulum exercises daily. We begin active-assist range of motion exercises after about 3-4 weeks and begin a strengthening program after approximately 3 months.

Outcomes/Evidence in the Literature

Abdel, M.P.. “Arthroscopic management of native shoulder septic arthritis”. J Shoulder Elbow Surg. vol. 22. 2013. pp. 418-21. (In a retrospective review of 50 patients with septic arthritis of the GH joint treated with arthroscopic irrigation and debridement, the authors found that 16 patients (32%) required repeat operations, two of whom required multiple operations to adequately treat the infection. This high rate of repeat operations is consistent with other reported series. One patient developed bilateral avascular necrosis of both humeral heads. Overall, five patients (17%) died within the first post-operative year, though no death was related to the surgical procedure.)

Lossos, I.S.. “Septic arthritis of the glenohumeral joint. A report of 11 cases and review of the literature”. Medicine (Baltimore). vol. 77. 1998. pp. 177-87. (Six cases of septic arthritis of the GH joint treated with a combination of serial shoulder aspirations or open irrigation and debridement and prolonged parenteral antibiotics. They found that, of the four patients with appropriate follow up, the only patient who was not treated with serial aspiration or open drainage (parenteral antibiosis alone) developed a recurrent GH infection of the same pathogen. Adequate range of motion was reported for those who were treated with serial aspiration (1) and open drainage (2). No deaths or serious morbidity were noted.)

Duncan, S.F., Sperling, J.W.. “Treatment of primary isolated shoulder sepsis in the adult patient”. Clin Orthop Relat Res. vol. 466. 2008. pp. 1392-6. (Nineteen patients over a 10-year period with isolated septic arthritis of the GH joint were reviewed. All patients were treated surgically – Nine with open irrigation and debridement and 10 arthroscopically. Intra-operatively, 12 patients exhibited cartilaginous erosions and 12 had irreparable rotator cuff repairs, which were debrided. All of these patients’ motion was restricted to less than 60 degrees of forward elevation and 30 degrees of external rotation. Overall, three patients died. One died of multisystem organ failure and was excluded from review, and two others died prior to the study commencement. On final follow-up, only three patients were pain free; three had mild pain, 10 had moderate pain with activity and two had constant pain. One patient underwent a hemiarthroplasty after a humeral head resection was performed to contain the infection.)

Cleeman, E.. “Septic arthritis of the glenohumeral joint: a review of 23 cases”. J Surg Orthop Adv. vol. 14. 2005. pp. 102-7. (Twenty-three cases of GH septic arthritis over a 14-year period at one hospital were reviewed and it was found that 87% of patients had, at least, one major medical co-morbidity, with an average of two. Staphylococcus aureus was identified in 70% of positive cultures, with 17% being Methicillin-resistant (MRSA). Patients were treated with either serial aspiration or surgery (arthroscopy, arthrotomy, or both), and all patients received parenteral antibiotics. The authors noted a trend towards a shorter hospital stay for those treated surgically, but this was not significant. Post-operative follow-up was poor, with only 23% of patients available for final follow up. At an average of five years post-infection, 80% (4/5) of patients reported no shoulder pain with the arm at their side, but the same number also reported difficulty sleeping comfortably and a limited ability to lift or carry items because of the shoulder.)

Leslie, B.M.. “Septic arthritis of the shoulder in adults”. J Bone Joint Surg. vol. 71. 1989. pp. 1516-22. (Retrospective findings from a cohort of 18 patients with septic arthritis of the GH joint. Results were quite poor. 18 patients’ records with GH arthritis were evaluated, and all but one patient had a serious medical co-morbidity. Intravenous drug users and post-operative infections were excluded. They reported that eight patients had an antecedent shoulder aspiration on the affected side. Patients were treated with serial joint aspirations or surgery, but the authors noted that 7 out of 10 patients treated with repeat aspiration went on to surgical treatment. The other eight patients had prompt surgical treatment. Average follow-up was 2.6 years (range 1-10). Of the three patients treated with aspiration only, one died of cardiac arrest, one had no motion of the GH joint and one had no active motion, but had passive flexion and abduction of 90 degrees. One of the seven treated with initial aspiration and subsequent arthrotomy died, three had flexion to 90 degrees or greater, one had flexion of less than 45 degrees and the remaining two had no active GH motion. Of those treated with prompt surgical management, two had flexion of 90 degrees of more, two had flexion of less than 45 degrees and four had no motion of the GH joint.)

Chirag, A.S.. “Septic arthritis of the acromioclavicular joint – a report of four cases”. Bull NYU Hosp Jt Dis. vol. 65. 2007. pp. 308-11. (Four cases of AC joint septic arthritis were described. One patient had a history of multiple myeloma and developed septic arthritis of the left AC joint, which was treated surgically and with long-term antibiotics. Ten months later his contralateral AC joint became infected and was treated in the same fashion. Both shoulders went on to heal without complications or recurrent infection. The two other patients were treated with AC joint aspiration and needle irrigation along with parenteral antibiotics. Both patients healed uneventfully and without complications or recurrence.)

Noh, K.C.. “Arthroscopic treatment of septic arthritis of acromioclavicular joint”. Clin Orthop Surg. vol. 2. 2010. pp. 186-90. (A case report of a septic AC joint in a 63-year old diabetic. The patient was treated surgically with an arthroscopic irrigation and debridement of the subacromial space along with a distal clavicle resection. Six weeks of parenteral antibiotics completed his treatment, and his two-year post-op Constant-Murley shoulder score was excellent.)

Ross, J.J., Shamsuddin, H.. “Sternoclavicular septic arthritis: review of 180 cases”. Medicine (Baltimore). vol. 83. 2004. pp. 139-48. (A review of 180 evaluated cases dating back to the 1970’s. While surgery was performed in only 58% of patients, 11 of 72 (16%) patients treated conservatively eventually required operative treatment. Furthermore, they demonstrated that a limited debridement, without resection of the SC joint, often required a more extensive debridement, as was seen in 13 of the 54 patients who underwent SC resections.)

Chun, J.M.. “Resection arthroplasty for septic arthritis of the sternoclavicular joint”. J Shoulder Elbow Surg. vol. 21. 2012. pp. 361-6. (A retrospective review of patients who underwent SC joint resection arthroplasty for septic arthritis of the SC joint. Ten patients evaluated between 1996 and 2008 were followed after surgery for a mean of 35.4 months. Seven of ten patients had pre-existing conditions. Four of ten patients received antibiotics prior to surgery, three as an alternative to surgery and one who was misdiagnosed with cellulitis. All patients underwent SC joint resection with intramedullary ligament reconstruction and received 4 to 8 weeks of parenteral antibiotics. Post-operatively, all infections were controlled, and only one patient’s treatment was complicated by sepsis and pneumonia. At final follow-up the mean ranges of motion were 146 degrees of forward flexion (135°-155°), 48 degrees of external rotation (40°-55°) and internal rotation ranged from T5 to L3. The mean pain score was 1.4. Radiographically, they noted a mean superior clavicular translation of 1.4 mm.)

Rockwood, CA. “Resection arthroplasty of the sternoclavicular joint”. J Bone Joint Surg Am. vol. 79-A. 1997. pp. 387-93. (This study highlights the importance of preserving the costoclavicular (rhomboid) ligament when performing SC joint resection. Eight patients who had a primary resection arthroplasty with the costoclavicular ligament left intact were compared with seven patients who underwent revision surgery with reconstruction of the costoclavicular ligament. All patients in the intact group had excellent outcomes, compared to only three patients in the reconstruction group.)

Summary

Septic arthritis of the native shoulder joints is an uncommon orthopaedic infection. GH and AC septic arthritis typically affects the elderly, the immunocompromised, and those with one or several systemic comorbidities. While septic arthritis of the SC joint also affects those with medical comorbidities, it is more frequently seen in intravenous drug users in a younger patient population. Prompt diagnosis is essential for proper treatment, and blood work, imaging, and arthrocentesis are paramount to establishing the diagnosis and formulating the treatment plan. Arthroscopic irrigation and debridement is our recommendation for treatment of GH septic arthritis, though good results have been shown with open approaches as well. Chondral erosion and irreparable rotator cuff tears portend poor post-operative function and range of motion.

AC and SC joint sepsis may be treated conservatively with arthrocentesis and needle irrigation and parenteral antibiotics. When clinical improvement does not manifest with conservative treatment, open irrigation and debridement with respective distal or medial clavicle excision is indicated. We recommend consultation with a cardiothoracic surgeon if any medial clavicle bony excision is required. Broad-spectrum antibiotics should be started immediately after obtaining joint aspirate cultures, and organism-specific parenteral antibiotics should be continued with the guidance of an infectious disease specialist. Rapid therapy and functional range of motion is recommended to maximize results after treatment.

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