Management of Common Football-Related Injuries About the Shoulder

Introduction

Injuries to the shoulder girdle are common across all levels of American football. The duties of sports medicine physicians include implementing up-to-date, evidence-based diagnostics, and treatments. Team physicians must educate and communicate with athletes, coaches, family members, and others about a player’s condition, proposed interventions, and a timeline for return to play. In this review article, we present a practical guide for evaluation and treatment of the 5 most common shoulder injuries in American football: acromioclavicular (AC) joint separation, glenohumeral (GH) instability, rotator cuff pathology, pectoralis major (PM) injury, and peripheral nerve injury.

Incidence and Magnitude of Football-Related Shoulder Injuries

Football is a widely practiced sport in the United States, with National Collegiate Athletic Association (NCAA) football participation increasing 12% from 2009 to 2019 [22]. The sport’s continued growth emphasizes the importance of injury trend analysis to improve preventative measures and promote safe return to play.

Shoulder injuries constitute 10% to 20% of all football injuries [36,81]. An epidemiological study of NCAA men’s football players from 2014 to 2019 reported that shoulder injuries comprised 13.3% of all injuries sustained (15.4% during games and 11.9% during practices) [22]. National Football League (NFL) data show a disproportionate shoulder injury burden occurring during the preseason, suggesting that deconditioning may play a role in injury [41,81].

The AC joint is the most commonly injured shoulder structure in football, with 41% of all collegiate football shoulder injuries and 40% of injuries to NFL quarterbacks [58,81]. Players are 12 times more likely to injure their AC joint in a game than in practice [36,81].

Glenohumeral joint instability is another common injury in this population [19,81]. A single NFL team experience from 1980 to 2008 showed that 10% of players reported a history of GH joint instability prior to joining the team, with 13% experiencing instability while playing for that team [64,81]. Furthermore, data from the annual NFL combine demonstrated that GH joint instability is the ninth most common diagnosis overall and the fourth leading cause for surgery in their athletes [18,81]. Studies suggest the risk of shoulder dislocation is much higher in games than in practice [41,81]. Anderson et al [4] reported on 403 shoulder instability events in the NFL resulting in missed time and found that 65% occurred during games, and the most common mechanism was contact (85%). A history of shoulder instability is shown to decrease the likelihood of making an NFL team for offensive and defensive lineman and is correlated with a shorter career [18,81]. National Football League players with surgically corrected instability demonstrated analogous risk of recurrence compared to athletes without a prior history of instability [60,81], while nonoperatively treated players displayed higher recurrence rates than those who underwent surgical intervention [60,81].

A retrospective investigation of shoulder and elbow injuries in NCAA football players from 2009 to 2010 through 2013 to 2014 found a total of 1187 shoulder and elbow injuries; the most common were AC joint separations (30% of all shoulder and elbow injuries), anterior shoulder subluxation (9%), shoulder contusion (9%), and rotator cuff tear/sprain (8%) [45].

Patient Evaluation

The setting of evaluation is an essential consideration. The point of care (POC) setting includes on-field or sideline evaluation, while clinic evaluation occurs in a training room or a physician’s office. Regardless of setting, the tenets of evaluation remain consistent: (1) establish a differential diagnosis, (2) determine the need for acute intervention, (3) formulate a plan of care, and (4) set a timeline for safe return to play. Challenges unique to each setting should be considered.

If POC field evaluation occurs with a player down, the history should focus on mechanism and brief symptom review. The physician must first clear the cervical spine before moving to the shoulder. The goals of POC assessment are to determine whether any immediate intervention, such as a shoulder reduction or transport for fracture, may be necessary and begin to develop a differential diagnosis. The point of care sideline evaluation should include a detailed history regarding the injured shoulder and a more detailed examination. The goal of POC sideline assessment is to determine whether the player should be removed from play for further evaluation. Obstructions to care on the field can come from other players or referees, protective equipment, lack of detailed history, or unclear mechanism and on the sidelines from coaches, the player, or parents. If a detailed examination is necessary, the player should be removed from play for training room evaluation.

We cannot overstate the utility of identifying the injury mechanism. At the NFL and elite college level, this can be aided by sideline video review. At lower levels, this includes descriptions by the injured athlete and real-time observations from the physician, players, coaches, or spectators.

Clinical evaluation should include a thorough history and physical examination, including both basic and more provocative directed maneuvers.

Diagnosis and Management of Select Injuries

AC Joint Injury

Case

When an 18-year-old right-hand-dominant male high school quarterback is sacked from the left side, the adducted right shoulder is driven into the ground. On POC evaluation, the player states “my right shoulder hurts” and “my arm is tingling.” The cervical spine is cleared, and palpation reveals isolated tenderness and prominence of the AC joint with pain-free passive midranges of motion.

The AC joint is a diarthrodial, synovial joint that contributes to proper scapulothoracic mechanics. The AC ligaments confer stability within the anteroposterior (AP) plane, while the coracoclavicular (CC) ligaments provide vertical stability [9,116]. Injury to the AC joint, including disruption of these supportive ligamentous structures, is a leading source of shoulder pain in competitive football [36,53].

Diagnosis

The most common injury mechanism is a direct impact with the arm in an adducted position. Given the mechanism and the POC examination of pain about the AC joint and ipsilateral transient dysesthesias, a more focused sideline examination should be conducted after protective equipment is removed. Palpation of the AC and sternoclavicular (SC) joints, along with the clavicle and coracoid, may rule out SC joint instability and clavicle or coracoid fracture. In this case, a presumed diagnosis of Grade 2 AC separation with transient stretch brachial plexopathy is made. Given the player’s inability to throw the football, he is restricted from further play in the game.

A detailed examination occurs in the training room. Joint reduction is tested with direct pressure or asking the patient to shrug. Inability to reduce the joint implies interposition of overlying deltotrapezial fascia and a higher injury severity. In a cross-body adduction test, the athlete’s arm is forward flexed to 90° and adducted [24,70]. A visible posterior prominence with this maneuver suggests posterior instability.

Radiographic evaluation should include Grashey AP, scapular Y lateral, and axillary views. Bilateral upright Zanca views are also of great utility in grading injury magnitude [119], enabling a comparative assessment of the CC interval (Fig. 1). Though not widely used, a stress adduction view involves a scapular Y lateral radiograph with the arm in cross-body adduction [111], with a clavicle that appears “overriding” in relation to the acromion, which suggests a higher severity of injury.

Fig. 1.

Bilateral Zanca radiograph demonstrating a left acromioclavicular joint dislocation. The coracoclavicular distance is measured as the vertical distance between the superior margin of the coracoid and the inferior margin of the clavicle. Relative displacement is made by comparing the coracoclavicular distance of the injured side (a) with the uninjured side (b).

Image adapted from Trainer et al [111].

The classification described by Rockwood in 1984 has provided a lexicon for conceptualizing, communicating, and treating AC joint injuries (Table 1) [46,99]. More recently, Type 3 injuries have been sub-classified into stable (3A) and unstable (3B) injuries based on physical exam and imaging characteristics [10]. It is paramount for the treating physician to readily classify AC joint injuries to guide subsequent treatment.

Table 1.

Rockwood classification of acromioclavicular joint injuries.

Type	AC ligaments	CC ligaments	CC distance increase
I	Sprained	Intact	Normal
II	Torn	Sprained	<25%
III	Torn	Torn	25%-100%
IV	Torn	Torn	Increased
V	Torn	Torn	>100

AC acromioclavicular; CC coracoclavicular.

Management

Rockwood Types 1 and 2 injuries are typically treated nonoperatively [78], including temporary restriction from football-related activities, cryotherapy, oral anti-inflammatory medications, and physical rehabilitation targeting restoration of scapular kinematics and shoulder range of motion [29,68,104]. Additional shoulder padding may further mitigate the player’s pain during play. Return to play is based on symptom resolution/tolerance and varies from 1 to 4 weeks. Elite athletes may receive a local anesthetic injection to mitigate pain prior to competition, though this is not advised in younger players.

Rockwood Types 4 and 5 injuries are often treated surgically [56,75,108]. An athlete may proceed with initial nonoperative treatment, particularly if wishing to return mid-season [38], and consider post-season surgical intervention. Our surgical preference is a reconstruction technique that avoids bone tunnels, followed by 4 to 6 months of supervised rehabilitation.

Management of Rockwood Type 3 injuries has been controversial [32,89,107,111]. Individualized treatment should consider the timing of competitive play (in-season vs out-of-season) and the player’s long-term athletic goals. Our preference is an initial course of nonoperative management, reserving surgery for those with persistent symptoms at 3 months. Athletes should be encouraged that rates of returning to competitive sports following surgery exceed 90% [102,113]. Additionally, delayed operative treatment of AC joint injuries does not confer inferior clinical outcomes in comparison to patients who undergo early surgical treatment [79].

GH Joint Dislocation

Case

A 25-year-old left-hand-dominant male NFL safety incurs a right shoulder injury while making a tackle. Immediate video review shows the right arm abducted during a tackle from behind. On POC evaluation, he states “my shoulder is out” and “my fingers are tingling.” The cervical spine is cleared. There is anterior prominence of the shoulder.

The GH joint is a diarthrodial, ball-and-socket joint that has the greatest range of motion of any synovial joint, with a degree of inherent instability [37,63,92]. Stability of the GH joint is conferred by bony and soft tissue (both static and dynamic) restraints, including glenoid version, GH ligaments, joint capsule, labrum, and rotator cuff [63,92,100]. Traumatic dislocations of the GH joint are a significant cause of disability and missed playing time in competitive football, comprising 9% to 20% of all shoulder and elbow injuries in NCAA and NFL players [4,45,82].

Diagnosis

This case suggests an anterior dislocation with an abducted and externally rotated position at time of injury [43,92], and POC examination with anterior shoulder prominence, loss of the normal deltoid contour beneath the lateral acromion, and arm position held in slight abduction and external rotation. In contrast, posterior dislocations occur with a posteriorly directed axial force against a flexed, adducted, and internally rotated arm (most common among offensive and defensive linemen) [4,92,97,98], and examination commonly demonstrates the arm internally rotated and adducted against the patient’s abdomen with a hollow anterior shoulder.

Early diagnosis of GH joint dislocation is essential, as timely closed reduction is most successful prior to the onset of pain and muscle spasm [3,47]. The athlete in this case underwent on-field gentle reduction and was removed to the sideline and restricted from play.

For anterior dislocations, simple traction–counter traction maneuvers with the patient supine are often successful when performed in the acute setting. The Kocher technique for anterior GH joint dislocation involves maximal external rotation of the forearm with the elbow flexed at 90° and progressive gentle adduction until reduction [47]. The Milch (authors’ preferred) technique involves gentle abduction and external rotation of the arm, with the physician’s thumb placed over the anterior shoulder to gently reduce the humeral head over the anteroinferior glenoid rim [3,47,73]. These techniques are associated with successful reduction in more than 80% of cases and can be performed on the playing field or sideline treatment table, without removal of the shoulder pads. Posterior GH joint dislocations are less common and more likely to spontaneously reduce. Multiple reduction techniques have been described, which emphasize longitudinal traction, internal rotation of the arm and an anterior/laterally directed force against the proximal humerus in an attempt to dislodge the humeral head from the posterior glenoid [44,47,76,117]. If initial reduction maneuvers are unsuccessful in the setting of anterior or posterior shoulder dislocation, additional attempts may be deferred until local intra-articular anesthetic or conscious sedation in a monitored setting is available.

Clinical and radiographic assessment of recurrent instability risk is essential. Physical examination signs of anterior shoulder instability include the apprehension test, relocation test, and release test. Radiographic evaluation should begin with Grashey AP, scapular Y lateral, and axillary views. A pathognomonic finding for a posterior GH joint dislocation on the AP radiograph is a “lightbulb” sign, which likens the appearance of the posteriorly dislocated and internally rotated humeral head to that of lightbulb. An axillary or Velpeau view is critical for identifying the direction of a GH joint dislocation and confirming reduction [14,97].

Cross-sectional imaging is the gold standard for assessment of associated soft tissue injuries and bone loss following GH joint dislocations. Computed tomography (CT) scanning is helpful in assessing glenoid and humeral bone loss following a dislocation event and is essential for preoperative planning in surgical cases. Magnetic resonance imaging (MRI) assesses the status of soft tissue stabilizers and articular cartilage injuries following GH joint dislocations. Identifying concomitant soft tissue and bony injuries associated with traumatic GH joint instability, such as humeral avulsion of the glenohumeral ligament (HAGL) lesions, anterior labroligamentous periosteal sleeve avulsions (ALPSAs), rotator cuff tears, glenolabral articular disruption (GLAD) lesions, glenoid bone defects, Hill–Sachs defects is essential.

Management

Immediate treatment following traumatic anterior GH joint dislocation includes brief sling immobilization, restriction from football-related activities, oral anti-inflammatory medications, cryotherapy, and a guided progressive rehabilitation program. Return to play typically occurs 2 to 4 weeks after injury, and is allowed if strength and motion are restored, and apprehension is absent. Stabilization or motion-limiting brace may be worn, though existing literature does not support decreased rates of recurrent instability [83].

Recurrence rates following first-time traumatic anterior GH joint dislocations depend on a variety of factors (including sex, age, ligamentous laxity, and activity level), with young, male football players associated with a 75% to 94% risk of recurrent instability [34,33,83,92]. For this reason, we counsel younger athletes to consider early surgery, while older athletes may choose to return to play in the same season after discussing the risks of doing so. Surgical management is typically divided into soft tissue procedures and bone augmentation procedures. The degree of glenoid bone loss and the presence of a Hill–Sachs lesion are key determinants of surgical decision-making. Provencher et al [92] summarized current treatment options for anterior GH joint instability based on the percentage of glenoid bone loss and Hill–Sachs lesion morphology (Table 2), although no consensus algorithm exists. We emphasize the importance of individualized surgical techniques and postoperative protocols, although return to play is typically not permitted until 5 to 6 months postoperatively [34].

Table 2.

Treatment algorithm for anterior shoulder instability based on glenoid bone loss and Hill–Sachs lesion morphology.

Glenoid bone loss (%)	On-track Hill–Sachs lesion	Off-track Hill–Sachs lesion
0%-13.5%	Arthroscopic stabilization	Arthroscopic stabilization + remplissage Open stabilization Bone augmentation procedure
13.5%-25%	Arthroscopic stabilization ± remplissage Open stabilization Bone augmentation procedure a	Arthroscopic stabilization + remplissage Open stabilization Bone augmentation procedure
>25%	Bone augmentation procedure	Bone augmentation procedure

Adapted from Provencher et al [92].

^aBone augmentation procedure may include Latarjet procedure with coracoid or distal clavicle autograft or distal tibia allograft augmentation.

Treatment of posterior GH joint subluxations/dislocations often involves a course of non-surgical management, including restriction from football-related injuries, cryotherapy, and progressive rehabilitation, with a focus on rotator cuff strengthening and periscapular stabilization. Open or arthroscopic posterior stabilization is effective for recurrent instability and is associated with good patient outcomes in more than 80% of patients at mid-term follow-up [17]. In the setting of significant bone loss, the McLaughlin procedure (reverse Hill–Sachs lesion ~20%) [71] or the lesser tuberosity osteotomy (reverse Hill–Sachs 20%-40%), may be used to provide better fill of the bony defect [100]. Due to the low occurrence of these procedures, data on clinical outcomes are limited. Return to football typically occurs 6 to 8 months postoperatively.

Rotator Cuff Injuries

Case

After a 21-year-old right-hand-dominant male collegiate wide receiver dives to make a catch with arms outstretched, he runs off the field clutching his right shoulder. A POC examination reveals no deformity, preserved active range of motion, and pain and weakness with forward flexion and external rotation. Within 10 minutes, he becomes pseudoparalytic.

The rotator cuff acts as a “force couple” and centers the humeral head to the glenoid [7,43] throughout range of motion [7]. Common injuries to the rotator cuff include tendonitis, contusion, and partial and full-thickness tears [43]. In a study of a single professional football team, rotator cuff contusions accounted for 47% of all shoulder injuries [26,43]. Rotator cuff injury has been reported as the third most common shoulder injury among athletes at the NFL combine [58,61], with linemen representing 20% to 25% of all shoulder injuries in that population [43,58,61]. It is important to note that although rotator cuff injuries are fairly common, tears of the rotator cuff are infrequent, with rates as low as 1.8% per year, [58,61], and nearly, half of these injuries occurring in offensive linemen [43,59].

The most common mechanism of injury in contact athletes is through direct trauma or impingement, whereas a more common mechanism in overhead athletes is cuff attrition [26,43]. A 2004 investigation by Kelly et al [59] found that 14% of all shoulder injuries in NFL quarterbacks were due to overuse, with rotator cuff tendinitis most common (6.1%).

Diagnosis

Rotator cuff evaluation should focus on bilateral active/passive range of motion, strength, and neurovascular exam [7]. A rotator cuff injury presents with loss of active motion while maintaining passive motion [7,77,105]. Evaluation involves each of the following 4 rotator cuff muscles:

• Subscapularis. In the belly-press test, the patient is asked to rest their palm at their abdomen and press internally. A positive test is the inability to maintain the elbow forward, instead using shoulder extension and wrist flexion to press down [7,96].

• Supraspinatus. The Jobe or “empty can” test places the supraspinatus tendon in a position of maximal stress; pain or weakness during examination is a positive finding [7,57]. The arm is placed in flexion to 90° in the scapular plane with the forearm in maximum pronation and shoulder internally rotated. Downward pressure is then placed to the arm [7]. Although not sensitive, it has been found to be up to 90% specific [7,54,67].

• Infraspinatus. Strength is tested with resisted external rotation while the arm is adducted to the patient’s side. The external rotation lag sign is performed by positioning the arm in 20° of flexion with the elbow flexed to 90° and the forearm is passively externally rotated to its maximum extent and released. If the patient cannot maintain this position, it is considered a positive lag sign [7,52]. Note that the lag sign may be inaccurate in the setting of restricted range of motion, as with capsular adhesions [55].

• Teres minor. The hornblower sign is performed with the patient’s arm passively abducted and externally rotated to 90°. The inability to maintain this position is a positive sign indicating deficiency of the teres minor, while pain during resistance in this position may indicate tendinopathy or a small tear [7,115].

In the case of our wide receiver, initial weakness progressed to pseudoparalysis. While rotator cuff contusion is far more common than a tear, MRI is advised. For the immature athlete, observation for improvement over 1 to 4 weeks is reasonable prior to imaging.

Management

An important aspect of rotator cuff management is the acute determination of a contusion versus tear, as the former allows for a more aggressive physical therapy protocol [26] and may be augmented with subacromial corticosteroid injection. Most patients with rotator cuff contusions have short recovery times after rehabilitation, but bone bruises on MRI or long-term tendinopathy may lead to a protracted recovery, often requiring a subacromial corticosteroid injection to facilitate return to play [26].

Few studies report on rotator cuff injuries in football athletes. Blevins et al [12] reported on a small cohort of 10 (9 professional and 1 competitive) athletes with a mean age of 40 years (range: 24-36 years). The mean delay from injury to surgery was 9 weeks (range: 3-24 weeks), with final diagnoses of 2 rotator cuff contusions, 5 partial tears, and 3 full-thickness tears and statistically significant improvements in postoperative pain and function scores.

Pectoralis Major Tears

Case

A 26-year-old right-hand-dominant male NFL linebacker injures his right shoulder while tackling. On POC evaluation, he states “something popped in my chest.”

The PM is formed by the clavicular and sternocostal heads, which combine to form a triangular sheet of tissue that inserts onto the intertubercular sulcus of the humerus [40,49]. Injuries can occur at any point on the PM and may involve either or both structural heads [21,28,40,69,80]. The injury spectrum ranges from contusion or sprain to complete rupture [6,28,69,109].

While PM tears are relatively rare injuries, football players are at increased risk due to the physical demands of their sport [15,16,101,118]. National Football League studies report an incidence between .004 and .60 per 10,000 exposures [15,101,118], with a gradual increase likely due to a combination of more aggressive weight training and advanced fitness programs [118]. Direct or indirect trauma from an eccentric load during tackling or blocking may cause a PM injury [6,40,103]. Prompt identification and management generally results in return to pre-injury strength and function [15,16,101,118].

Diagnosis

Players may report a tearing sensation or a sudden pop in the shoulder with associated spasm and severe, sharp, or burning pain. Physical exam may reveal swelling and ecchymosis to the chest wall, axilla, and proximal biceps, with loss of the normal contour of the axilla or a “webbed” deformity [49]. Provocative tests include resisted bilateral horizontal adduction at 90° of scapular elevation and resisted internal rotation while maintaining the shoulder in adduction [5].

For a suspected PM injury, imaging should be used to confirm the diagnosis. Ultrasound is effective and efficient for identifying PM tears, but it requires an experienced technician [49,84,94]. Magnetic resonance imaging can identify location, severity, and degree of tendon retraction in acute PM injuries [20,65,74]. A dedicated chest MRI should be ordered to ensure adequate injury visualization and is associated with excellent sensitivity and specificity [23,27].

The Tietjen [109] classification system, later modified by Bak [6], has most commonly been used. More recently, Cordasco proposed a new classification system to describe these injuries and direct treatment (Table 3) [6,69,109].

Table 3.

Classification and management of pectoralis major injuries based on Tietjen/Bak and Cordasco classification systems.

	Injury	Recommended treatment
Tietjen/Bak
Type I	Contusion or sprain	Conservative
Type II	Partial tear	Conservative vs operative
Type III	Complete tear
A	Muscle origin	Conservative
B	Muscle belly	Conservative
C	Myotendinous junction	Operative
D	Tendon	Operative
E	Bony avulsion	Operative
F	Intratendinous rupture	Operative
Cordasco
Type I	Contusion or sprain	Conservative
Type II	Isolated single head
A	Muscle origin	Conservative
B	Muscle belly	Conservative
C	Myotendinous junction	Operative
D	Tendon	Operative
Type III	Combined heads
A	Muscle origin	Conservative
B	Muscle belly	Conservative
C	Myotendinous junction	Operative

Management

Injuries and tears of the muscle origin or belly (Cordasco Types IIA, IIB, IIIA, IIIB) are managed nonoperatively. Treatment typically involves a period of restriction from football-related activities, sling immobilization, oral anti-inflammatory medications, and a graduated physical therapy program. Most players return to full football activities within 4 weeks [88].

Surgical repair is indicated for Cordasco Types IIC, IID, IIIC, IIID and IIIE injuries. An aggressive approach to surgical management for borderline cases is typically utilized, as surgical repair has been associated with superior outcomes in strength and function [8,31]. A variety of operative techniques have been reported, including bone trough, suture anchor, and cortical button repairs, with similar clinical and functional outcomes [1,49,50,88,93] Full, unrestricted return to sport typically occurs within 4 to 6 months following surgery [28,30,49,103]. During the first year back to sport, an abduction-external rotation (ABER) restriction brace may be considered. Studies show that with prompt recognition and proper treatment, nearly 90% of football players who sustain PM tears return to play at their pre-injury performance level [118].

Peripheral Nerve Injury

Case

An 18-year-old left-hand-dominant male high school fullback injures his left shoulder while blocking. He continues to play, and after the game complains of “burning” over the lateral deltoid.

Although uncommon, peripheral nerve injuries can be a potentially devastating sports-related injury that may be associated with sensory or motor deficits [91]. Football players are at increased risk, with prior studies demonstrating that between 20% and 30% of all sports-related peripheral nerve injuries occur in American football [62,66,91]. The axillary nerve segment proximal to the quadrilateral space is most frequently associated with shoulder injuries, such as anterior GH joint dislocations and proximal humerus fractures [39,62,85,91,106,114]. Less common mechanisms are direct/blunt trauma, brachial neuritis, and compression in the quadrilateral space [11,62,87,91,106]. Blunt trauma injuries are associated with nerve rupture and have a worse prognosis [51,86,91]. Early recognition and diagnosis of peripheral nerve injuries is critical to management, as a delay has negative implications on recovery [87,91,106]. Although literature specific to axillary nerve injury in professional football players is scarce, evidence indicates that most axillary nerve injuries present as part of a combined brachial plexus injury.

Diagnosis

The axillary nerve is responsible for motor innervation of the deltoid and teres minor [7]. Evaluation of axillary nerve integrity should focus on active shoulder abduction. Sensory function of the axillary nerve can be evaluated by sensation over the lateral aspect of the shoulder in the “regiment badge” area via the superior lateral cutaneous nerve [7]. It is important to note that incomplete paralysis can occur due to sparing of either the anterior or posterior portion of the deltoid [106]. Diagnosis may be difficult due to lack of atrophy, preserved rotator cuff function, and normal range of motion [42,106]. Incomplete injuries may manifest in increased exercise fatigue and decreased abduction strength [106].

The cervical spine and brachial plexus should be thoroughly evaluated. Physical examination should include active and passive range of motion, as well as strength testing focused on abduction and external rotation in 90° of abduction, as these maneuvers will isolate the deltoid and the teres minor [106]. Atrophy will not be evident acutely, but atony may be present during resistance testing.

Standard radiographs of the shoulder and cervical spine should be obtained to evaluate for fracture, dislocation, or other contributing pathology [106] and baseline electromyographic (EMG) and nerve conduction studies (NCS) be initiated within 2 to 4 weeks of injury with follow-up evaluation at 12 weeks after injury [106]. Electromyographic and nerve conduction studies confirm diagnosis and are a reference point for future assessments of recovery [106]. In long-term cases, MRI may reveal a combined nerve injury, allow for delineation of involvement in smaller muscle groups, or reveal a mass lesion that may be contributing to a compressive neuropathy [106].

Management

Most patients with axillary nerve injury recover with nonoperative management [35,106]. Physical therapy emphasizes passive and active assisted range of motion to prevent contracture while awaiting return of normal motor function [106]. Outcomes related to nonoperative management of axillary nerve injury following atraumatic lesions and closed fractures and/or dislocations have been favorable, with symptom resolution within 2 years of injury [13,48,106,110].

The lack of clinical or EMG recovery at 12 weeks after injury may indicate the need for surgical intervention [2,25,106], with optimal results when performed within 3 to 6 months of injury [106], although functional improvement can occur when performed within 12 months [2,72,90,106]. Significant improvement is unlikely when surgery is performed more than 12 months from injury [25,106]. Interventions may include neurolysis, nerve decompression, nerve grafting, and neurotization [2,90,95,106,112].