Clinicians › Shoulder

Subacromial Decompression

Arthroscopic subacromial decompression for impingement and bursitis — operation and recovery.

78 citationsUpdated Sep 2026

For patients: a plain-language version of this topic is available. See the patient guide.

Overview

Subacromial decompression is a surgical intervention for shoulder impingement syndrome, indicated when mechanical impingement is present and pain persists despite nonsurgical measures [2]. Proper patient selection is critical, as appropriate indications result in excellent outcomes [3]. The procedure is effective in 70% to 75% of cases [5], leading to significant improvements in function and quality of life in a cost-effective manner [11]. Patients improve regardless of underlying depression or depressive symptoms [10], and the treatment remains a valid option for those selected according to national guidelines [20]. However, the evidence base is contested; while some argue that high-quality randomized placebo-controlled studies do not meet objective quality criteria [18], other data show that arthroscopic subacromial decompression provides no benefit over diagnostic arthroscopy or exercise therapy regarding return to work [19].

The clinical utility of subacromial decompression remains controversial, with conservative management serving as the initial mainstay and surgery reserved for failures [9]. Nonoperative treatment is appropriate as initial therapy, while operative management is considered when nonoperative measures fail [15]. A strong guideline recommendation exists against subacromial decompression surgery for adults with subacromial pain syndrome [8], as the procedure provided no important benefit compared with placebo surgery or exercise therapy and carries a small risk of serious harms [6]. Consequently, there is no current strong evidence to support either subacromial decompression or nonoperative treatment exclusively, requiring surgeons to rely on clinical judgment and careful patient selection [7]. Arthroscopic treatment should no longer be offered to people with subacromial impingement as surgery offers no discernible benefits but may result in harm, with the weight of evidence supporting nonoperative management or no treatment [30].

In the context of rotator cuff pathology, isolated subacromial decompression did not provide any clinical or structurally substantial benefit for the treatment of subacromial pain syndrome or the surgical repair of rotator cuff tears [1]. Five randomized trials found that formal subacromial decompression does not result in improved clinical outcomes up to 2 years after rotator cuff repair [14], and at short-term follow-up, it did not seem to significantly affect the outcome of arthroscopic rotator cuff repair [22]. Long-term clinical outcomes were significantly higher in patients treated only with rotator cuff repair compared to those who underwent repair with subacromial decompression [12]. Furthermore, both arthroscopic subacromial decompression and diagnostic arthroscopy resulted in significant improvements in pain and functional outcomes with no difference in the incidence of adverse events [4]. Patients with partial rotator cuff tears found coincidentally at surgery may not need to be addressed if consented for a subacromial decompression alone, as both groups had a similar final outcome [13]. This study may aid in improving patient outcome and especially patient selection for subacromial decompression [17].

Anatomy & Pathophysiology

Bony Anatomy

The scapula is a triangular bone attached to the axial skeleton via the clavicle at the acromioclavicular and sternoclavicular joints [57]. It spans the second through seventh ribs and serves as an attachment site for 17 muscles [69]. The basic part of the scapula is the body, which is triangular when viewed anteroposteriorly with its base situated superiorly and its apex inferiorly [57]. The glenoid is connected to the flat body of the scapula by the scapular neck [57]. The hook-shaped coracoid process curves forwards from the superior surface of the scapular neck [57]. On the posterior surface of the scapular body, the scapular spine arises and ends in a flattened bony process, the acromion, which curves forwards [57]. The highest concentration of bony mass in the scapula is found in the glenoid, the scapular neck (including the base of the coracoid process), and the lateral border of the scapular body [57]. Two bony pillars extend between the glenoid and the scapular body to transmit compressive forces from the glenoid fossa [57]. The lateral pillar connects the inferior border of the glenoid with the inferior angle, while the spinal pillar arises from the central part of the glenoid and continues medially to become part of the base of the scapular spine [57]. The weakest bone in the scapula is located primarily in the central part of the biomechanical body, specifically in the infraspinous fossa [57]. The weakest area of the circumference of the biomechanical body of the scapula is the connection of the scapular spine and the medial border of the scapula, known as the spinomedial angle [57].

The acromion has three ossification centers: the metacromion (base), the mesoacromion (middle), and the preacromion (tip) [58]. Failure of fusion of the acromial ossification centers results in os acromiale [58]. Os acromiale is incomplete fusion of secondary ossification centers, most commonly between the mesoacromion and meta-acromion [69]. The acromion has enlarged over evolutionary time to reflect the increasing role of the deltoid muscle in shoulder function [65]. The broader attachment of the deltoid on the acromion and its more distal insertion on the humerus have increased its mechanical advantage in shoulder motion [65]. The coracoid process has undergone an increase in size over evolutionary time [65]. With the shoulder in 90 degrees of abduction, the coracoid extension over the glenohumeral joint can mechanically limit anterior translation of the humerus relative to the glenoid [65].

The glenoid is a convex structure of shallow depth shaped like an inverted pear [55]. The glenoid cavity is a shallow socket, approximately one third the size of the humeral head [56]. The glenoid averages 5° of retroversion in relation to the axis of the scapular body [58]. The glenoid is retroverted approximately 5 degrees relative to the scapular body [69]. The humeral head averages 19° of retroversion and 41° of inclination (neck-shaft angle) [58]. The neck-shaft angle measures an average of 135 degrees, and the humeral head is retroverted an average of 30 degrees [56]. The humeral head is retroverted 30 degrees relative to the transepicondylar axis of the humerus [69]. The articular head of the humerus is spherical and has a diameter of 37 to 57 mm [55]. The most superior portion of the articular surface of the humeral head averages 8 mm above the greater tuberosity [55]. The humeral version averages 29.8 degrees, with a range of 10 to 55 degrees [55]. The head is inclined approximately 130 degrees with respect to the humeral shaft [55]. The head height is approximately 5.6 cm above the superior border of the pectoralis major tendon [69].

The anatomic neck of the proximal humerus is located at the junction of the articular surface and the tuberosities [55]. The surgical neck represents an indistinct region below the tuberosities but above the humeral shaft [55]. The greater tuberosity serves as the attachment site for the supraspinatus, infraspinatus, and teres minor tendons [55]. The lesser tuberosity serves as the attachment site for the subscapularis tendon [55]. The bicipital groove lies between the greater and lesser tuberosities and serves as a pathway for the long head of the biceps [55]. The distal aspect of the bicipital groove is internally rotated with respect to the proximal portion [55].

Soft Tissue Anatomy

The rotator cuff is a sheet of conjoined tendons closely applied over the shoulder capsule and inserting mainly into the greater tuberosity of the humerus [63]. The rotator cuff consists of four muscles: the subscapularis, supraspinatus, infraspinatus, and teres minor muscles [56]. The teres major is not a rotator cuff muscle [56]. The rotator cuff is made up of subscapularis in front, supraspinatus above, and infraspinatus and teres minor behind [63]. The subscapularis is inserted into the lesser tuberosity [63]. The cuff muscles serve as depressors of the humeral head to allow the deltoid to efficiently abduct the humerus [56]. The infraspinatus and teres minor are external rotators, while the subscapularis is an internal rotator of the humerus [56]. The rotator cuff has an important function in stabilizing the head of the humerus by pulling it firmly into the glenoid whenever the deltoid lifts the arm forwards or sideways [63]. The rotator cuff stabilizes the glenohumeral joint via joint compression [58].

The coracoacromial arch is a fibro-osseous canopy formed by the acromion process posterosuperiorly, the coracoid process anteriorly, and the coracoacromial ligament joining them [63]. The acromion, the coracoacromial ligament, and the coracoid process form the coracoacromial arch, a rigid bony-ligamentous structure that imparts stability to the shoulder girdle [55]. The subacromial bursa separates the tendons from the coracoacromial arch and allows them to glide [63]. The rotator cuff, subacromial bursa, and subdeltoid bursa pass underneath the coracoacromial arch [55]. The subscapular bursa lies between the subscapularis tendon and the neck of the scapula [59]. The subscapular bursa communicates with the joint cavity between the superior and middle glenohumeral ligaments [59]. The subscapular bursa protects the tendon of the subscapularis at the point where it passes under the base of the coracoid process and over the neck of the scapula [59]. The subscapular bursa is linked to the coracoid process by a suspensory ligament [59]. In 28% of specimens dissected by Colas and colleagues, the subscapular bursae merged with the subcoracoid bursae, forming a unique wide bursa in this region [59]. The subscapular bursa often houses loose bodies in the shoulder [59]. The subscapular bursa is a region in which synovitis of the shoulder may be most intense, where small fringes or villi can project into the joint cavity [59].

The rotator interval is defined as the region between the superior border of the subscapularis and the anterior border of the supraspinatus [59]. The rotator interval is defined medially by the base of the coracoid, superiorly by the supraspinatus tendon, and inferiorly by the subscapularis tendon [58]. The rotator interval includes the region of the superior glenohumeral ligament and coracohumeral ligament, in addition to the middle glenohumeral ligament [59]. The rotator interval contains the coracohumeral ligament, the superior glenohumeral ligament, and the intra-articular portion of the long head of the biceps tendon [58]. Plancher and colleagues found the average area of the rotator interval to be 20.96 mm [59]. Dynamic testing has shown that the subscapularis and supraspinatus dimensions as well as the total area of the rotator interval decrease significantly with internal rotation and open with external rotation [59]. Laxity of the rotator interval results in inferior laxity (the sulcus sign), and contracture of the interval is seen with adhesive capsulitis [58].

The tendons of the infraspinatus and supraspinatus muscles join approximately 15 mm proximal to their insertion [68]. The supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove [68]. The roof of the biceps sheath consists of a portion of the supraspinatus tendon, and a sheet of the subscapularis tendon forms the floor [68]. The coracohumeral ligament is a thick band of fibrous tissue extending from the coracoid process along the surface of the capsule to the tuberosities between the supraspinatus and subscapularis tendons [68]. The coracohumeral ligament is deep to the tendinous insertion of the cuff and blends with the capsule and supraspinatus tendon to form part of the roof of the biceps sheath [68]. The coracoacromial ligament contributes to anterosuperior stability in rotator cuff deficiency [69]. The coracoacromial ligament is the arthroscopic landmark for a complete release of the rotator interval for adhesive capsulitis [69].

The humeroscapular motion interface lies between the inner structures of the proximal humerus, rotator cuff, coracohumeral ligament, and biceps tendon sheath and the superficial layer of the acromion, deltoid, coracoacromial ligament, coracoid process, and the conjoined tendon [61]. Smooth, unrestricted motion at the humeroscapular motion interface is vital to shoulder mobility [61]. The axillary nerve has an intimate relationship within the humeroscapular motion interface [61]. The axillary nerve is a terminal branch coming off the posterior cord of the brachial plexus just proximal to the coracoid process [61]. The axillary nerve passes beneath the conjoined tendon anterior to the subscapularis 3 to 5 mm medial to the musculotendinous junction and then adjacent to the inferior capsule before entering the quadrilateral space posteriorly [61]. The axillary nerve splits into the anterior and posterior branches within the quadrangular space [61]. The anterior and middle deltoid muscle receives sole innervation from the anterior branch of the axillary nerve [61]. Posterior deltoid muscle innervation varies, with supply only from the anterior branch in 2.3% of cases, from the posterior branch in 8.5%, and from both branches in 89.1% [61]. The posterior branch of the axillary nerve branches to supply the teres minor muscle and then terminates as the superior lateral brachial cutaneous nerve [61]. In the anterolateral deltoid splitting approach, the axillary nerve crosses approximately 5 cm inferior to the anterolateral acromial corner [61]. In the posterior deltoid splitting approach, the axillary nerve is approximately 7 cm from the posterior acromial corner [61].

Vascular & Neural Anatomy

The proximal humerus receives its blood supply from the anterior and posterior humeral circumflex branches from the third division of the axillary artery [55]. The anterior humeral circumflex artery provides vascular inflow to the humeral head by way of its terminal anterolateral branch known as the artery of Laing or arcuate artery [55]. The major blood supply to the humeral head is through the ascending branch of the anterior humeral circumflex artery, which penetrates the head at the bicipital groove and becomes the arcuate artery [56]. The ascending branch of the anterior humeral circumflex artery courses parallel to the lateral aspect of the long head biceps tendon and enters the humeral head at the interface of the bicipital groove and greater tuberosity [55]. The acromial branch of the thoracoacromial artery runs on the medial aspect of the coracoacromial ligament [69].

The suprascapular artery passes superior to the superior transverse scapular ligament and the suprascapular nerve passes inferior to the ligament through the suprascapular notch [69]. The superior transverse scapular ligament arises from the medial base of the coracoid overlying the suprascapular notch [58]. The suprascapular artery runs superior to the superior transverse scapular ligament, and the nerve runs deep to the ligament [58]. Entrapment of the suprascapular nerve at the superior transverse scapular ligament causes denervation of both the supraspinatus and the infraspinatus [58]. At the spinoglenoid notch, both the artery and nerve are inferior to the inferior transverse scapular ligament [69]. The spinoglenoid ligament overlies the suprascapular nerve at the spinoglenoid notch [58]. Entrapment, traction, or compression of the suprascapular nerve at the spinoglenoid notch causes denervation of the infraspinatus [58].

Ligamentous Anatomy & Stability

The glenohumeral joint is composed of four articulations: sternoclavicular, acromioclavicular, glenohumeral, and scapulothoracic [68]. The glenoid labrum increases the depth of the socket by 50% around the humeral head [68]. The glenoid labrum provides concavity and up to 50% of marginal glenoid socket depth [58]. The glenoid articular surface and the labrum combine to create a socket that is approximately 9 mm deep in the superoinferior direction and 5 mm deep in the anteroposterior direction [68]. Adding the glenoid labrum increases the glenoid surface to 75% of the humeral head vertically and 57% horizontally [68]. The subchondral bone of the glenoid is relatively flat, and the articular concavity is augmented by cartilage and a circumferential labrum [58].

The superior shoulder suspensory complex provides a stable connection between the scapula and the axial skeleton [58]. The superior shoulder suspensory complex is composed of the glenoid, the coracoid process, the coracoclavicular ligaments, the distal clavicle, the acromioclavicular joint, and the acromion [58]. The superior strut of the superior shoulder suspensory complex comprises the middle clavicle [58]. The inferior strut of the superior shoulder suspensory complex comprises the lateral scapular border/spine of the scapula [58].

The coracohumeral ligament restricts external rotation in adduction, and it is a static restraint to inferior and posterior translation in adduction and external rotation [58]. The superior glenohumeral ligament is a primary static restraint against anterior translation with the arm at the side [58]. With the coracohumeral ligament, the superior glenohumeral ligament forms a pulley that provides restraint against medial subluxation of the long head of the biceps tendon [58]. The middle glenohumeral ligament is a primary static restraint against anterior translation with the arm in external rotation and 45° of abduction [58]. The anterior band of the inferior glenohumeral ligament is a primary static restraint against anterior-inferior dislocation of the glenohumeral joint in 90° of abduction and external rotation [58]. The posterior band of the inferior glenohumeral ligament is a primary static restraint against posterior-inferior translation in internal rotation and adduction [58]. The transverse humeral ligament is an important stabilizer of the biceps tendon [69].

Kinematics & Positioning

The scapula is anteverted on the chest wall approximately 30 degrees relative to the body [69]. The coracoid process has attachments to the coracoacromial ligament, coracoclavicular ligaments (conoid and trapezoid), conjoined tendon (coracobrachialis and short head of biceps), and pectoralis minor [69].

Classification

Copeland-Levy: This classification is suggested to standardize terminology for the arthroscopic evaluation of subacromial impingement lesions [99].

Acromial Morphology: The acromial morphology classification system is an unreliable method to assess the acromion [45]. Furthermore, the acromial index shows no association with the presence of rotator cuff disease [45].

Ellman: In a systematic review of partial-thickness rotator cuff tears, 587 articular-sided tears were classified as Ellman IA in 106 cases, IIA in 135 cases, and IIIA in 193 cases [31]. Among bursal-sided tears, there were 6 Ellman IB tears, 21 IIB tears, and 0 IIIB tears [31].

Snyder: Two studies within a systematic review of partial-thickness rotator cuff tears used the Snyder classification, describing 20 A2 tears, 29 A3 tears, and 19 A4 tears [31]. Additionally, two shoulders with isolated bursal-sided tears were classified as Snyder B1, three as B2, and ten as B3 [31].

Boileau: In a study of irreparable rotator cuff tears, the extent of the tear and tendon retraction were measured intra-operatively in both the coronal and sagittal planes according to the classification system described by Boileau et al. [140].

Samilson-Prieto: In a study of reversed arthroscopic subacromial decompression for symptomatic irreparable rotator cuff tears, there was an average increase of 1 grade in the scoring for osteoarthritis according to the Samilson-Prieto classification [141].

Clinical Presentation

Subacromial impingement syndrome is characterized by a history of subacromial pain associated with specific activities or motions [83]. Patients typically present with a normal range of motion of the shoulder [83]. Clinical criteria for subacromial shoulder pain include a painful arc between 40° to 120° in abduction and flexion, as well as pain with active arm elevation [37]. Tenderness to palpation of rotator cuff tendons is also a recognized clinical criterion [37].

Special Tests: * Impingement Signs: A typical positive impingement sign involves pain elicited when the examiner prevents scapular rotation and raises the patient's arm in forced elevation, causing the greater tuberosity to press the rotator cuff against the acromion [83]. A second positive impingement sign is the elicitation of pain on simultaneous forward flexion of the humerus to 90 degrees [83]. * Specific Maneuvers: Clinical criteria include positive tests by Neer, Hawkins-Kennedy, Speed, or Jobe [37]. A positive empty can test is also indicative of subacromial pathology [37]. * Resisted Motion: Criteria include resisted painful or weak shoulder abduction, as well as resisted or weak shoulder external rotation [37]. * Diagnostic Confirmation: A diagnosis may be based on Cyriax criteria, such as a painful arc or painful resisted abduction test [37]. Additionally, a positive impingement test with lidocaine serves as a clinical criterion [37].

Differential Diagnosis: Coracoid impingement should be included in the differential diagnosis when evaluating a patient with activity-related anterior shoulder pain [96]. Pigmented villonodular synovitis (PVNS) may present with sub-acromial erosion of the shoulder and should be considered in the differential diagnosis of patients presenting with shoulder pain [44].

Investigations

Imaging is an essential tool for evaluating shoulder pain, serving to establish the diagnosis, determine the severity of pathoanatomy, assist in surgical planning, and illustrate the condition to the patient [43]. Standardized plain films are almost always sufficient to garner the necessary information for shoulder evaluation [34]. Surgeons must resist the temptation to "overimage," obtaining only the scans or reconstructions necessary for patient care [34, 74]. Proper radiographic technique is as important as proper surgical technique to achieve the desired outcome [34].

Plain radiography: The standard shoulder radiographic series should include a true AP view in the scapular plane, an AP view, an axillary view, and a scapular Y view [79]. At minimum, two views are required: an anteroposterior projection in the plane of the glenoid and an axillary projection with the arm in abduction [72]. The first key view is the AP in the plane of the scapula, taken so the x-ray beam passes through the glenohumeral joint [34]. This view demonstrates the superoinferior position of the humeral head relative to the glenoid, the presence of osteophytes, joint space narrowing, and the degree of medial displacement of the humerus [34]. The true AP view in the scapular plane visualizes the anterior greater tuberosity in profile and can reveal proximal humeral migration [79].

The second key view is the axillary view, taken with the arm in the functional position of elevation in the plane of the scapula [34]. Referred to as the "truth view," it demonstrates glenohumeral relationships in the functional position of elevation [34]. This view is necessary for evaluating glenohumeral joint instability and determining the humeral head position in the glenoid fossa [79]. It enables the measurement of posterior subluxation or "functional decentering" that is not evident in images taken with the arm at the side [34]. The degree of posterior subluxation can be measured by the position of the center of the humeral head in relation to the plane of the scapula, the position of the center of the humeral head in relation to the glenoid face, or the point of contact of the humeral articular surface on the glenoid articular surface [34]. The point of contact reflects the degree of centering of the net humeral joint reaction force on the glenoid [34]. Malcentering of this force leads to posterior instability, posterior glenoid wear, and "rocking horse" loosening of prosthetic glenoid components [34].

The scapular Y view provides visualization of the coracoacromial arch and can reveal coracoacromial spurs associated with rotator cuff pathology [79]. The acromiohumeral distance is normally 7 to 14 mm [79]. The width of the glenohumeral joint space should be symmetric superiorly and inferiorly [79]. Neer classified acromial morphology as type I (flat), type II (curved), and type III (hooked) [79]. Type III acromial morphology has a correlation with the presence of rotator cuff disease, although no direct causal relationship has been demonstrated [79]. The Neer classification has shown relatively poor interobserver reliability [79].

MRI: MRI is the modality of choice for evaluating the rotator cuff, biceps, and subacromial/subdeltoid bursa [78]. T2-weighted MRI provides better visualization of full-thickness rotator cuff tears [78]. MRI is useful to identify osteonecrosis of the humeral head, bone tumours, labral tears, and rotator cuff tears [72]. The accuracy of MRI for identifying labral tears and rotator cuff tears is enhanced by combining the scan with arthrography [72]. MR arthrography is considered the benchmark for evaluation of labral tears and is rarely indicated for evaluation of rotator cuff pathology [78].

For the detection of full-thickness rotator cuff tears, MRI has a sensitivity of 100%, a specificity of 68%, a positive predictive value of 85%, a negative predictive value of 100%, and an accuracy of 89% [79]. Younger age, lower BMI, more functional capacity, a shorter symptomatic period, reversible changes on MRI, and higher Constant and ASES scores at the first evaluation were good prognostic factors for the natural course of subacromial impingement syndrome [146].

CT: CT is helpful for planning fracture surgery and shoulder joint replacement [72]. CT arthrography is indicated when MRI or MR arthrography is contraindicated, such as in patients with pacemakers or vascular clips [78]. CT scans have the disadvantage of being taken with the arm in the adducted position, unlike the axillary truth view [34]. Preoperative imaging with 3D CT may assist surgeons in performing arthroscopic suprascapular notch decompression [143].

Ultrasonography: Ultrasonography is a low-cost alternative to MRI and arthrography for evaluating both skeletal and soft-tissue structures of the shoulder [78]. It is a simple and accurate test for identifying rotator cuff tears and calcific tendinitis [72]. Ultrasonography can provide immediate, real-time visualization of the rotator cuff, biceps tendon, and calcific deposits [78]. It can be used to measure the subacromial space and detect atrophy of rotator cuff muscles [78]. Ultrasound can be useful in guiding injections or barbotage, such as aspirating calcific deposits in the rotator cuff [72].

For the detection of full-thickness rotator cuff tears, ultrasonography has a sensitivity of 98%, a specificity of 80%, a positive predictive value of 90%, a negative predictive value of 95%, and an accuracy of 94% [79]. Ultrasonography is highly operator-dependent and is not as useful for evaluating labral tears or rotator cuff tears that are very small or larger than 3 cm [78]. Bilateral ultrasonographic findings question ultrasonography's ability to discriminate between shoulders with and without subacromial pain syndrome based on measurements of subacromial structures alone [50]. Rotator cuff and subacromial bursa pathology were the most common findings on ultrasound and MRA in a prospective study of shoulder pain in primary care [134].

Arthroscopy: Arthroscopy is useful for diagnosing and treating subacromial impingement, intra-articular lesions, detachment of the glenoid labrum, and rotator cuff tears [72]. With the advent of arthroscopy for subacromial decompression, intra-articular pathology not previously visualized at the time of open decompression can now be assessed and used as a tool with which to predict clinical outcomes [26]. Arthroscopic subacromial decompression is a tool that has been validated with symptomatic and functional improvement in both short- and long-term studies for patients with isolated subacromial impingement [26].

Other Considerations: A robust approach to imaging the shoulder needs to recognize that the shoulder is a three-dimensional structure that cannot be represented by a single planar view [74]. Critical relationships, such as the degree of centering of the humeral head, change with the position of the arm [74]. Shoulder pathology may be found in a large number of different bones and soft tissues [74]. Overlying and superimposed structures as well as metallic implants may complicate imaging the structures of interest [74]. PVNS may present with sub-acromial erosion of the shoulder and should be considered in the differential diagnosis of patients presenting with shoulder pain [44]. In a cohort of patients with subacromial impingement and glenohumeral arthritis, preoperative radiographs and arthroscopic inspection were examined as prognosticators for long-term symptoms and functional outcomes [26]. Radiographs obtained in studies of subacromial impingement and glenohumeral arthritis are examined for features consistent with osteoarthritis and are subsequently staged 0 to 3, from none to severe [26]. The gold standard for preoperative evaluation of glenohumeral arthritis is direct visualization of the articular surface intraoperatively [26]. Arthroscopy for lavage and debridement of osteoarthritic lesions of the glenohumeral joint has provided inconsistent relief without enduring results [26]. The significance of arthroscopic subacromial decompression in the presence of glenohumeral degenerative joint disease to postoperative outcome remains unclear [26].

Treatment

Non-Operative

Subacromial decompression with bursectomy and acromioplasty is the standard of care for refractory subacromial impingement [29]. Acromioplasty may be an effective treatment option for subacromial impingement refractory to conservative therapy [39].

Operative

Indications: Arthroscopic subacromial decompression is presented as an alternative to open anterior acromioplasty in advanced stage II and selected cases of stage III impingement syndrome [21]. The procedure is indicated for refractory subacromial bursitis and subacromial impingement [53]. It is also a routine portion of rotator cuff repair exposure [53].

Surgical Approach / Technique: The procedure aims to remove the subacromial bursa, which can serve as a pain generator, as well as any osteophytes on the undersurface of the acromion, which can lead to impingement and, in some circumstances, bursal-sided rotator cuff tears [53]. Multiple randomized clinical trials have demonstrated no benefit for this procedure as an initial treatment in patients with subacromial bursitis [53]. In patients with symptoms consistent with shoulder impingement syndrome, arthroscopic subacromial decompression did not differ from diagnostic arthroscopy (placebo control) for shoulder pain at 24 months [25]. Surgical groups had better outcomes for shoulder pain and function compared with no treatment but this difference was not clinically important [49].

The modification of the traditional Neer acromioplasty (the two-step process) is performed with the patient in a semi-seated position, with the affected shoulder at the corner of the operating table and the upper limb draped free [46]. The incision is made along the lateral border of the acromion in the lines of Langer [46]. The incision extends from the mid-lateral aspect to the anterior surface of the acromion, approximately seven to eight centimeters [46]. The skin and subcutaneous fat down to the fascia overlying the deltoid muscle are undermined medially as far as the acromioclavicular joint and four centimeters laterally beyond the lateral edge of the acromion [46]. The demarcation between the anterior and lateral components of the deltoid muscle is palpable as a slight depression at the anterolateral corner of the acromion and is generally identified by a fibrous raphe between the two heads of the muscle [46]. The raphe is split with a small periosteal elevator from the anterolateral corner of the acromion distally in the line of the fibers, for a distance of three to four centimeters [46]. A periosteal elevator is used to free the adhesions between the anterior and lateral fibers of the deltoid from the roof of the bursa [46]. It is common to penetrate the roof of the bursa inadvertently during this maneuver, but this is of little consequence, as the hypertrophic bursa is usually excised [46].

Arthroscopic steps include (1) placement of the arthroscope in the subacromial space and establishment of a lateral working portal, (2) performance of a thorough subacromial bursectomy, (3) achievement of hemostasis and subperiosteal exposure of the undersurface of the acromion, and (4) smoothing of the undersurface of the acromion and removal of any anterolateral osteophytes [53]. After general anesthesia combined with brachial plexus block, the patient is placed in the lateral decubitus position with the arm in 30° abduction and with 10 pounds of traction [138]. The bony landmarks are identified and marked, together with anterior, posterior, and lateral portals [138]. After the posterior and anterior portals are created, a routine diagnostic arthroscopy is performed in the articular cavity [138]. Any intra-articular pathology is assessed and addressed appropriately if necessary, including articular cartilage, glenoid labrum, glenohumeral ligament, biceps, and subscapularis [138]. The 30 arthroscope is then inserted into the subacromial space, and a lateral portal is established to assess the reparability of the RCT based on tear location, size, degree of retraction, tension, tissue quality, and other variables [138].

Multiple arthroscopic techniques using different portals have been described, with accompanying possible injuries to the surrounding neurovascular and musculotendinous structures [135]. With the described technique, multiple shoulder pathologies can be treated arthroscopically using a single working portal, aiming to decrease morbidity and allow early mobilization and rehabilitation, decreasing postoperative analgesia and opioid use, with better cost-effectiveness [135]. In terms of subjective improvement, overall satisfaction, UCLA score, and shoulder strength, the two techniques were equivalent [32].

Adjuncts: A modified Neer acromioplasty, subacromial decompression, and débridement of massive, irreparable lesions of the supraspinatus and infraspinatus tendons was performed in fifty-seven patients [41]. The results of the present study suggest that, with proper rehabilitation, adequate decompression of the subacromial space, anterior acromioplasty, and débridement of massive tears of the rotator cuff can lead to the relief of pain and the restoration of shoulder function [41]. Subacromial decompression via open acromioplasty and tuberoplasty, combined with glenosphere exchange, successfully resolved symptomatic subacromial impingement and restored function in a patient with acromion fracture nonunion following reverse shoulder arthroplasty [54]. This report describes a simplified subacromial arthroscopic technique for decompression of the suprascapular nerve at the suprascapular notch and spinoglenoid notch while providing the surgeon with a facile, effective method to concomitantly evaluate and treat comorbid shoulder pathology [94]. Four portals were used in line with the scapular spine (S1, S2, S3, S4) [139]. The suprascapular pedicle was visualized passing under the supraspinatus muscle [139]. No injury to the nerve was identified after performing the technique [139]. Decompression was complete in 18 of 20 cases at the suprascapular notch and in all cases at the spinoglenoid notch [139]. With this technique, arthroscopic decompression of the nerve at the suprascapular and spinoglenoid notches is anatomically possible [139].

Pain Management: According to this study, the use of a pain pump after arthroscopic subacromial decompression did not have any long-term effects on the patients' recovery, return to work, or final result at the minimum 2-year follow-up [27]. Compared with placebo, SABER-Bupivacaine reduced pain and opioid analgesic consumption over 72 hours after arthroscopic subacromial decompression and prolonged the time to first use of opioid rescue analgesia [103]. Patients treated with SSN blocks had less pain overall, which led to a decreased need for analgesics in comparison to the subacromial infiltration and placebo groups [108]. Continuous subacromial infiltration of 0.25% bupivacaine at a rate of 6 mL/h is clinically safe but ineffective for postoperative pain relief after open acromioplasty and rotator cuff repair, as it had no effect on pain perception or morphine requirements [136]. Although interscalene block remains the gold standard, subacromial bursa block provides effective, safe, and easily administered postoperative analgesia in patients with an intact rotator cuff undergoing arthroscopic subacromial decompression [137].

Other Considerations: Patients treated by debridement of the calcific deposit and concomitant subacromial decompression required a longer time to return to unrestricted activity without pain [16]. The utility of acromioplasty at the time of rotator cuff repair has come into question, with new studies showing no significant benefit [39]. There is no need to perform subacromial decompression in partial bursal-sided rotator cuff repairs to obtain a good result [92]. Shoulder arthroscopy is becoming the standard of care for most shoulder pathologies, owing to fewer complications, minimal invasiveness, faster functional recovery, and less postoperative pain [135]. Requirement of high surgical skills and technically demanding [135]. Need for more specialized curved instruments important, an early return to activities, decreased postoperative analgesia requirements, less scarring, and deltoid sparing [135].

Complications

Thromboembolism: Pulmonary embolism secondary to subclavian venous thrombosis has been reported following rotator cuff tendon repair [149].

Other Considerations: Prior subacromial decompression serves as an independent risk factor for acromial stress fracture after reverse total shoulder arthroplasty, conferring a 26% higher risk [150]. The procedure probably carries a small risk of serious harms [6]. The use of a pain pump after arthroscopic subacromial decompression did not have any long-term effects on patients' recovery, return to work, or final result at the minimum 2-year follow-up [27].

Recovery

Light activity (weeks): More than 90% of patients manage to return to driving within 4 weeks following arthroscopic subacromial decompression and acromioclavicular joint excision [90].

Full activity (months): More than 90% of patients manage to return to work within 6 weeks following arthroscopic subacromial decompression and acromioclavicular joint excision [90].

Functional milestones: Voluntary activation of the infraspinatus is impaired in patients with subacromial pain syndrome and improves immediately following pain relief from injection and after a 6-week exercise program [102].

Other Considerations: Recovery of subjective shoulder function required almost 3 months on average for patients undergoing arthroscopic removal of chronic symptomatic calcifications of the supraspinatus tendon without acromioplasty [48]. Results were much slower and overall poorer in patients with whiplash injury compared to controls after arthroscopic subacromial decompression [126]. The use of a pain pump after arthroscopic subacromial decompression did not have any long-term effects on the patients' recovery, return to work, or final result at the minimum 2-year follow-up [27].

Key Evidence

• [L1] Subacromial decompression did not provide any clinical or structurally substantial benefit for the treatment of subacromial pain syndrome or the surgical repair of rotator cuff tears. [1] (10.2106/jbjs.rvw.19.00045)
• [L5] The panel agreed that subacromial decompression is a good choice for shoulder impingement if there is evidence of mechanical impingement with pain not responding to nonsurgical measures. [2] (10.1016/j.arthro.2021.09.031)
• [L5] Proper indications for shoulder subacromial decompression result in excellent outcomes. [3] (10.1016/j.arthro.2021.04.023)
• [L1] Both arthroscopic subacromial decompression and diagnostic arthroscopy resulted in significant improvements in pain and functional outcomes with no difference in the incidence of adverse events. [4] (10.1136/bmj.k2860)
• [L4] Isolated arthroscopic subacromial decompression is effective in 70% to 75% of cases. [5] (10.1016/j.otsr.2014.09.006)
• [L1] Subacromial decompression surgery provided no important benefit compared with placebo surgery or exercise therapy, and probably carries a small risk of serious harms. [6] (10.1136/bjsports-2018-100486)
• [L5] There is no current and strong evidence to either support subacromial decompression or nonoperative treatment, requiring surgeons to rely on clinical judgment and careful patient selection. [7] (10.1016/j.arthro.2020.03.024)
• [L1] The guideline panel makes a strong recommendation against subacromial decompression surgery for adults with subacromial pain syndrome. [8] (10.1136/bmj.l294)
• [L5] The treatment of subacromial impingement syndrome remains controversial, with conservative management being the initial mainstay and surgery reserved for failures. [9] (10.1111/j.1758-5740.2012.00205.x)
• [L3] Patients improved after undergoing subacromial decompression regardless of underlying depression or depressive symptoms. [10] (10.1016/j.jseint.2023.11.012)
• [L4] Subacromial decompression leads to significant improvement in function and quality of life in a cost effective manner. [11] (10.1308/003588414x14055925061478)
• [L3] The long term clinical outcomes resulted significantly higher in patients treated only with RCR respect the ones in patients underwent to RCR with subacromial decompression. [12] (10.1186/s12891-019-3032-z)
• [L4] Both groups had a similar final outcome revealing that a partial rotator cuff tear may not need to be addressed if found coincidentally at surgery, particularly if consented for a subacromial decompression alone. [13] (10.4103/0973-6042.102558)
• [L1] Five randomized trials found that formal subacromial decompression does not result in improved clinical outcomes up to 2 years after rotator cuff repair. [14] (10.1016/j.arthro.2012.06.003)
• [L5] Nonoperative treatment is appropriate as initial therapy, while operative management including arthroscopic subacromial decompression, debridement, or repair is considered when nonoperative treatment fails. [15] (10.5435/00124635-199901000-00004)
• [L3] Patients treated by debridement of the calcific deposit and concomitant subacromial decompression required a longer time to return to unrestricted activity without pain. [16] (10.1016/j.jse.2010.10.038)
• [L2] This study may aid in improving patient outcome and especially patient selection for subacromial decompression. [17] (10.1007/s00167-013-2386-2)
• [Letter] The authors argue that the referenced high-quality randomized placebo-controlled studies do not fulfill the criteria of high quality when evaluated objectively, despite the debate surrounding subacromial decompression. [18] (10.1016/j.arthro.2022.06.011)
• [L1] Arthroscopic subacromial decompression provided no benefit over diagnostic arthroscopy or exercise therapy on return to work in patients with shoulder impingement syndrome. [19] (10.1186/s12891-021-04768-7)
• [L4] Arthroscopic subacromial decompression is a valid treatment, reducing pain and improving quality of life for patients selected for surgery according to the Danish national guidelines. [20] (10.1016/j.jse.2017.03.028)
• [L4] Arthroscopic subacromial decompression is presented as an alternative to open anterior acromioplasty in advanced stage II and selected cases of stage III impingement syndrome. [21] (10.1016/j.arthro.2009.10.003)
• [L1] At short-term follow-up, subacromial decompression did not seem to significantly affect the outcome of arthroscopic rotator cuff repair. [22] (10.1016/j.arthro.2006.10.011)
• [L1] In patients with symptoms consistent with shoulder impingement syndrome, arthroscopic subacromial decompression did not differ from diagnostic arthroscopy (placebo control) for shoulder pain at 24 months. [25] (10.2106/jbjs.18.01342)
• [L4] [26] (10.1067/mse.2002.124427)
• [L2] According to this study, the use of a pain pump after arthroscopic subacromial decompression did not have any long-term effects on the patients' recovery, return to work, or final result at the minimum 2-year follow-up. [27] (10.1016/j.arthro.2008.07.013)
• [L5] Subacromial decompression with bursectomy and acromioplasty is the standard of care for refractory subacromial impingement. [29] (10.1016/j.eats.2023.04.012)
• [L5] Arthroscopic treatment should no longer be offered to people with subacromial impingement as surgery offers no discernible benefits but may result in harm, and the weight of evidence supports nonoperative management or no treatment. [30] (10.1016/j.arthro.2022.03.017)
• [L4] [31] (10.1016/j.arthro.2010.09.019)
• [L1] In terms of subjective improvement, overall satisfaction, UCLA score, and shoulder strength, the two techniques were equivalent. [32] (10.1067/mse.2002.120915)
• [L1] [37] (10.1136/bjsports-2016-096515)
• [Paper] [39] (10.1016/j.ocl.2013.12.003)
• [L4] [41] (10.2106/00004623-199506000-00006)
• [L4] Imaging is an essential tool for evaluation of patients with shoulder pain; understanding the extent of an injury with imaging is key to successful management. [43] (10.1016/j.csm.2013.03.009)
• [L4] PVNS may present with sub-acromial erosion of the shoulder and should be considered in the differential diagnosis of patients presenting with shoulder pain. [44] (10.1007/s00167-009-0752-x)
• [L3] The acromial morphology classification system is an unreliable method to assess the acromion, and the acromial index shows no association with the presence of rotator cuff disease. [45] (10.1016/j.jse.2011.09.028)
• [L4] However, recovery of subjective shoulder function required almost 3 months on average. [48] (10.1177/2325967114533646)
• [L1] Surgical groups had better outcomes for shoulder pain and function compared with no treatment but this difference was not clinically important. [49] (10.1016/s0140-6736(17)32457-1)
• [L3] These findings question ultrasonography's ability to discriminate between shoulders with and without SAPS based on measurements of subacromial structures alone. [50] (10.1016/j.jse.2025.02.020)
• [Paper] [53] (10.2106/jbjs.st.o.00011)
• [L4] Subacromial decompression via open acromioplasty and tuberoplasty, combined with glenosphere exchange, successfully resolved symptomatic subacromial impingement and restored function in a patient with acromion fracture nonunion following reverse shoulder arthroplasty. [54] (10.1016/j.xrrt.2024.11.003)
• [L4] [83] (10.2106/00004623-199072020-00003)
• [L3] The results obtained in the present study suggest that more than 90% of the patients manage to return to driving within 4 weeks and to work within 6 weeks following arthroscopic subacromial decompression and acromio-clavicular joint excision. [90] (10.1111/j.1758-5740.2010.00048.x)
• [L5] There is no need to perform subacromial decompression in partial bursal-sided rotator cuff repairs to obtain a good result. [92] (10.1016/j.arthro.2017.02.015)
• [L4] This report describes a simplified subacromial arthroscopic technique for decompression of the suprascapular nerve at the suprascapular notch and spinoglenoid notch while providing the surgeon with a facile, effective method to concomitantly evaluate and treat comorbid shoulder pathology. [94] (10.1016/j.arthro.2008.10.024)
• [L4] Coracoid impingement should be included in the differential diagnosis when evaluating a patient with activity-related anterior shoulder pain. [96] (10.1177/03635465000280010501)
• [L4] Hence, we suggest the Copeland-Levy classification be used to standardize terminology of the subacromial impingement lesion. [99] (10.1016/j.jse.2017.07.018)
• [L2] Voluntary activation of the infraspinatus is impaired in patients with subacromial pain syndrome and improves immediately following pain relief from injection and after a 6-week exercise program. [102] (10.1016/j.jse.2025.01.020)
• [L1] Compared with placebo, SABER-Bupivacaine reduced pain and opioid analgesic consumption over 72 hours after arthroscopic subacromial decompression and prolonged the time to first use of opioid rescue analgesia. [103] (10.5435/jaaosglobal-d-21-00287)
• [L1] Patients treated with SSN blocks had less pain overall, which led to a decreased need for analgesics in comparison to the subacromial infiltration and placebo groups. [108] (10.1016/j.arthro.2011.05.016)
• [L3] Although there was an improvement in shoulder scores after Arthroscopic Subacromial decompression, results were much slower and overall poorer in patients with whiplash injury compared to controls. [126] (10.1111/j.1758-5740.2012.00199.x)
• [L2] Rotator cuff and subacromial bursa pathology were the most common findings on ultrasound and MRA. [134] (10.1186/1471-2474-12-119)
• [Paper] [135] (10.1016/j.eats.2021.01.005)
• [L1] Continuous subacromial infiltration of 0.25% bupivacaine at a rate of 6 mL/h is clinically safe but ineffective for postoperative pain relief after open acromioplasty and rotator cuff repair, as it had no effect on pain perception or morphine requirements. [136] (10.1016/j.jse.2004.04.005)
• [L2] Although interscalene block remains the gold standard, subacromial bursa block provides effective, safe, and easily administered postoperative analgesia in patients with an intact rotator cuff undergoing arthroscopic subacromial decompression. [137] (10.1016/j.jse.2007.05.014)
• [L5] [138] (10.1016/j.eats.2022.06.026)
• [L5] [139] (10.1016/j.jse.2007.10.002)
• [L3] [140] (10.1007/s00167-012-2317-7)
• [L4] [141] (10.1016/j.jse.2009.10.001)
• [L5] Preoperative imaging with 3D CT may assist surgeons in performing arthroscopic SSN decompression. [143] (10.1016/j.jse.2014.07.018)
• [L2] Younger age, lower BMI, more functional capacity, a shorter symptomatic period, reversible changes on MRI, and higher Constant and ASES scores at the first evaluation were good prognostic factors for the natural course of subacromial impingement syndrome. [146] (10.1016/j.jse.2015.06.007)
• [L4] This is the first reported case of pulmonary embolism due to subclavian venous thrombosis following rotator cuff tendon repair. [149] (10.1016/j.jse.2008.02.001)
• [L3] Prior subacromial decompression is an independent risk factor for acromial stress fracture after reverse total shoulder arthroplasty, conferring a 26% higher risk. [150] (10.1016/j.jseint.2025.05.014)

See Also

• Rotator Cuff
• Rotator cuff repair
• Os Acromiale
• Calcific Tendinitis
• Reverse Shoulder Arthroplasty
• Shoulder Arthroscopy
• Total shoulder arthroplasty

References

[1] Subacromial Decompression Is Not Beneficial for the Management of Rotator Cuff Disease. JBJS Reviews. 2020. DOI: 10.2106/jbjs.rvw.19.00045

[2] Subacromial Decompression in Patients With Shoulder Impingement With an Intact Rotator Cuff: An Expert Consensus Statement Using the Modified Delphi Technique Comparing North American to European Shoulder Surgeons. Arthroscopy. 2021. DOI: 10.1016/j.arthro.2021.09.031

[3] Proper Indications for Shoulder Subacromial Decompression Result in Excellent Outcomes. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.04.023

[4] Subacromial decompression versus diagnostic arthroscopy for shoulder impingement: randomised, placebo surgery controlled clinical trial. BMJ. 2018. DOI: 10.1136/bmj.k2860

[5] Failed subacromial decompression. Risk factors. Orthopaedics & Traumatology: Surgery & Research. 2014. DOI: 10.1016/j.otsr.2014.09.006

[6] Subacromial decompression surgery for adults with shoulder pain: a systematic review with meta-analysis. British Journal of Sports Medicine. 2019. DOI: 10.1136/bjsports-2018-100486

[7] No Indications for Subacromial Decompression in Rotator Cuff Tendinopathy: A Level I Evidence Clinical Guideline. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2020. DOI: 10.1016/j.arthro.2020.03.024

[8] Subacromial decompression surgery for adults with shoulder pain: a clinical practice guideline. BMJ. 2019. DOI: 10.1136/bmj.l294

[9] Current Concepts in Subacromial Impingement and the Role of Acromioplasty. Shoulder & Elbow. 2012. DOI: 10.1111/j.1758-5740.2012.00205.x

[10] Arthroscopic subacromial decompression improved outcomes in situationally depressed patients compared to clinically depressed or nondepressed patients. JSES International. 2024. DOI: 10.1016/j.jseint.2023.11.012

[11] Does arthroscopic subacromial decompression improve quality of life. The Annals of The Royal College of Surgeons of England. 2015. DOI: 10.1308/003588414x14055925061478

[12] Arthroscopic rotator cuff repair with and without subacromial decompression is safe and effective: a clinical study. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-019-3032-z

[13] Mid-term results of arthroscopic subacromial decompression in patients with or without partial thickness rotator cuff tears. International Journal of Shoulder Surgery. 2012. DOI: 10.4103/0973-6042.102558

[14] The Changing Role of Acromioplasty. Arthroscopy. 2012. DOI: 10.1016/j.arthro.2012.06.003

[15] Partial-Thickness Tears of the Rotator Cuff: Evaluation and Management. Journal of the American Academy of Orthopaedic Surgeons. 1999. DOI: 10.5435/00124635-199901000-00004

[16] Calcific tendonitis of the shoulder: is subacromial decompression in combination with removal of the calcific deposit beneficial?. Journal of Shoulder and Elbow Surgery. 2011. DOI: 10.1016/j.jse.2010.10.038

[17] Predictive value of preoperative clinical examination for subacromial decompression in impingement syndrome. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2386-2

[18] Regarding “Subacromial Decompression in Patients With Shoulder Impingement With an Intact Rotator Cuff: An Expert Consensus Statement Using the Modified Delphi Technique Comparing North American to European Shoulder Surgeons”. Arthroscopy. 2022. DOI: 10.1016/j.arthro.2022.06.011

[19] Return to work after subacromial decompression, diagnostic arthroscopy, or exercise therapy for shoulder impingement: a randomised, placebo-surgery controlled FIMPACT clinical trial with five-year follow-up. BMC Musculoskeletal Disorders. 2021. DOI: 10.1186/s12891-021-04768-7

[20] Acromioplasty in patients selected for operation by national guidelines. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2017.03.028

[21] Arthroscopic Subacromial Decompression: Analysis of One‐ to Three‐Year Results. Arthroscopy. 2010. DOI: 10.1016/j.arthro.2009.10.003

[22] Arthroscopic Rotator Cuff Repair With and Without Subacromial Decompression: A Prospective Randomized Study. Arthroscopy. 2007. DOI: 10.1016/j.arthro.2006.10.011

[25] In Shoulder Impingement Syndrome, Subacromial Decompression Did Not Differ from Diagnostic Arthroscopy for Shoulder Pain at 24 Months. Journal of Bone and Joint Surgery. 2019. DOI: 10.2106/jbjs.18.01342

[26] Results of arthroscopic subacromial decompression in patients with subacromial impingement and glenohumeral degenerative joint disease. Journal of Shoulder and Elbow Surgery. 2002. DOI: 10.1067/mse.2002.124427

[27] Long‐term Effect of the Use of a Pain Pump After Arthroscopic Subacromial Decompression. Arthroscopy. 2008. DOI: 10.1016/j.arthro.2008.07.013

[29] In‐Office Nano‐Arthroscopy of the Shoulder with Acromioplasty. Arthroscopy Techniques. 2023. DOI: 10.1016/j.eats.2023.04.012

[30] Editorial Commentary : Arthroscopic Treatment Should No Longer Be Offered to People With Subacromial Impingement. Arthroscopy. 2022. DOI: 10.1016/j.arthro.2022.03.017

[31] The Arthroscopic Management of Partial‐Thickness Rotator Cuff Tears: A Systematic Review of the Literature. Arthroscopy. 2011. DOI: 10.1016/j.arthro.2010.09.019

[32] Arthroscopic versus open acromioplasty: A prospective, randomized, blinded study. Journal of Shoulder and Elbow Surgery. 2002. DOI: 10.1067/mse.2002.120915

[34] Rockwood And Matsen S The Shoulder. Arthroscopic Management of Prearthritic and Arthritic Conditions of the Shoulder and the Postarthroplasty Shoulder > Radiographic Evaluation.

[37] Effectiveness of conservative interventions including exercise, manual therapy and medical management in adults with shoulder impingement: a systematic review and meta-analysis of RCTs. British Journal of Sports Medicine. 2017. DOI: 10.1136/bjsports-2016-096515

[39] The Role of Acromioplasty for Rotator Cuff Problems. Orthopedic Clinics of North America. 2014. DOI: 10.1016/j.ocl.2013.12.003

[41] Débridement of degenerative, irreparable lesions of the rotator cuff.. The Journal of Bone & Joint Surgery. 1995. DOI: 10.2106/00004623-199506000-00006

[43] Imaging of the Shoulder with Arthroscopic Correlation. Clinics in Sports Medicine. 2013. DOI: 10.1016/j.csm.2013.03.009

[44] Subacromial bony erosion: a rare presentation of pigmented villonodular synovitis of the shoulder. Knee Surgery, Sports Traumatology, Arthroscopy. 2009. DOI: 10.1007/s00167-009-0752-x

[45] Relationship of radiographic acromial characteristics and rotator cuff disease: a prospective investigation of clinical, radiographic, and sonographic findings. Journal of Shoulder and Elbow Surgery. 2012. DOI: 10.1016/j.jse.2011.09.028

[46] Shoulder impingement syndrome: diagnosis, radiographic evaluation, and treatment with a modified Neer acromioplasty.. The Journal of Bone and Joint Surgery. American Volume. 1993.

[48] Arthroscopic Removal of Chronic Symptomatic Calcifications of the Supraspinatus Tendon Without Acromioplasty. Orthopaedic Journal of Sports Medicine. 2014. DOI: 10.1177/2325967114533646

[49] Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. The Lancet. 2018. DOI: 10.1016/s0140-6736(17)32457-1

[50] Bilateral ultrasonographic findings in patients with unilateral subacromial pain syndrome and intact rotator cuff tendons. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2025.02.020

[53] Arthroscopic Subacromial Decompression and Acromioplasty. JBJS Essential Surgical Techniques. 2016. DOI: 10.2106/jbjs.st.o.00011

[54] Subacromial decompression for impingement syndrome following type II acromion fracture nonunion. JSES Reviews, Reports, and Techniques. 2025. DOI: 10.1016/j.xrrt.2024.11.003

[55] Rockwood And Matsen S The Shoulder. Shoulder and Elbow Specialty Clinic Workers’ Survey > ANATOMY.

[56] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 2Musculoskeletal Trauma Surgery > SHOULDER AND ARM INJURIES.

[57] Rockwood And Green S Fractures In Adults. 29: Principles of Nonunion and Bone Defect Treatment > Applied Anatomy Related to Scapular Fractures.

[58] Aaos Comprehensive Orthopaedic Review 3. Anatomy of the Shoulder, Arm, and Elbow > I. Shoulder.

[59] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > Bursae.

[61] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > EDITOR COMMENTARY.

[63] Apley And Solomon S Concise System Of Orthopaedics And Trauma. DISORDERS OF THE ROTATOR CUFF.

[65] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > Development of Individual Regions.

[68] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH BONE-PATELLAR TENDON-BONE GRAFT > SHOULDER INJURIES > ANATOMY AND BIOMECHANICS.

[69] Miller S Review Of Orthopaedics. Genetics of musculoskeletal conditions and abnormalities are summarized in Table 1.27 > UPPER EXTREMITY > SHOULDER.

[72] Apley And Solomon S Concise System Of Orthopaedics And Trauma. INVESTIGATION.

[74] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > SENIOR EDITOR COMMENTARY.

[78] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Shoulder Anatomy and Biomechanics, Clinical Evaluation, Imaging > Clinical Evaluation > Imaging.

[79] Aaos Comprehensive Orthopaedic Review 3. Imaging of the Shoulder and Elbow > I. Shoulder.

[83] Arthroscopic acromioplasty for lesions of the rotator cuff.. The Journal of Bone & Joint Surgery. 1990. DOI: 10.2106/00004623-199072020-00003

[90] Return to Work and Driving following Arthroscopic Subacromial Decompression and Acromioclavicular Joint Excision. Shoulder & Elbow. 2010. DOI: 10.1111/j.1758-5740.2010.00048.x

[92] Editorial Commentary: Subacromial Decompression Is Unnecessary in Most Routine Rotator Cuff Repairs. Arthroscopy. 2017. DOI: 10.1016/j.arthro.2017.02.015

[94] Arthroscopic Decompression of the Suprascapular Nerve at the Spinoglenoid Notch and Suprascapular Notch Through the Subacromial Space. Arthroscopy. 2009. DOI: 10.1016/j.arthro.2008.10.024

[96] Coracoid Impingement. The American Journal of Sports Medicine. 2000. DOI: 10.1177/03635465000280010501

[99] Intraobserver and interobserver reliability of the Copeland-Levy classification for arthroscopic evaluation of subacromial impingement. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2017.07.018

[102] Voluntary activation is impaired in subacromial pain syndrome but improves with pain relief and exercise. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2025.01.020

[103] SABER-Bupivacaine Reduces Postoperative Pain and Opioid Consumption After Arthroscopic Subacromial Decompression: A Randomized, Placebo-Controlled Trial. JAAOS: Global Research and Reviews. 2022. DOI: 10.5435/jaaosglobal-d-21-00287

[108] A Randomized Study of the Effectiveness of Suprascapular Nerve Block in Patient Satisfaction and Outcome After Arthroscopic Subacromial Decompression. Arthroscopy. 2011. DOI: 10.1016/j.arthro.2011.05.016

[126] Outcome of Arthroscopic Subacromial Decompression for Shoulder Impingement Syndrome after a Whiplash Type Injury. Shoulder & Elbow. 2012. DOI: 10.1111/j.1758-5740.2012.00199.x

[134] A prospective study of shoulder pain in primary care: Prevalence of imaged pathology and response to guided diagnostic blocks. BMC Musculoskeletal Disorders. 2011. DOI: 10.1186/1471-2474-12-119

[135] Shoulder Arthroscopic Rotator Cuff Repair With Biceps Tenodesis and Acromioplasty Using a Single Working Portal. Arthroscopy Techniques. 2021. DOI: 10.1016/j.eats.2021.01.005

[136] Continuous subacromial bupivacaine infusion for postoperative analgesia after open acromioplasty and rotator cuff repair: Preliminary results. Journal of Shoulder and Elbow Surgery. 2004. DOI: 10.1016/j.jse.2004.04.005

[137] Subacromial bursa block is an effective alternative to interscalene block for postoperative pain control after arthroscopic subacromial decompression: A randomized trial. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2007.05.014

[138] Computer Image‐Guided Precise Acromioplasty for Reducing the Critical Shoulder Angle. Arthroscopy Techniques. 2022. DOI: 10.1016/j.eats.2022.06.026

[139] Original portals for arthroscopic decompression of the suprascapular nerve: An anatomic study. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2007.10.002

[140] Surgical management of irreparable rotator cuff tears. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2317-7

[141] Reversed arthroscopic subacromial decompression for symptomatic irreparable rotator cuff tears: Mid-term follow-up results in 34 shoulders. Journal of Shoulder and Elbow Surgery. 2010. DOI: 10.1016/j.jse.2009.10.001

[143] Arthroscopic decompression at the suprascapular notch: a radiographic and anatomic roadmap. Journal of Shoulder and Elbow Surgery. 2015. DOI: 10.1016/j.jse.2014.07.018

[146] Medium-term natural history of subacromial impingement syndrome. Journal of Shoulder and Elbow Surgery. 2015. DOI: 10.1016/j.jse.2015.06.007

[149] Pulmonary embolism after acromioplasty and rotator cuff repair. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2008.02.001

[150] Prior subacromial decompression is a significant risk factor for development of acromial stress fracture after reverse total shoulder arthroplasty. JSES International. 2025. DOI: 10.1016/j.jseint.2025.05.014