Traumatic rotator cuff tears - Current concepts in diagnosis and management

Abstract

Rotator cuff tears represent one of common shoulder pathologies presenting over a wide spectrum of age groups and varying presentation. Typically, rotator cuff tears occur more frequently in elderly than in younger patients, following a chronic or acute-on-chronic course and usually secondary to due to tendon degeneration. Though there has been a considerable debate in the literature of the terms “acute” and “traumatic” used in the classification of rotator cuff tears, there appears to be consensus about the need for early diagnosis to facilitate prompt surgical treatment and the improve patient outcome. Significant differences in rotator cuff tears between those occurring in younger and older patients could be due to mechanism of injury, presentation, severity of the tear, biological healing potential and rehabilitation. Acute traumatic rotator cuff tears especially in younger age group represent a distinct entity from other patterns of rotator cuff tears. Consequently, a high index of suspicion, focused clinical examination, complementary imaging is a pre-requisite for an early diagnosis and effective management.

We analyze the biomechanical consequences of acute rotator cuff tears along with characteristic mechanism of injury and spectrum of tendon involvement. The evolving concepts in the diagnosis and management of these distinct injuries are discussed with review of current literature.

Rotator cuff tears (RCT) are a common causes of shoulder complaints and one of the leading causes of time lost from work or athletic activity.¹ The reported prevalence of traumatic RCT can be up to 40% of all RCT.² In general, they tend to be a common cause of morbidity in the elderly. RCT occur in patients of all ages and have the potential for both short and long-term disability if they are not appropriately managed. Despite the high prevalence of this disorder, the proper management of RCT has long been a source of debate among orthopedic surgeons.¹ It has been accepted that there is a role for both non-operative and operative management to improve outcomes due to RCT.³ Most studies focus on elderly patients and fail to delineate between a RCT in older and younger populations or traumatic and degenerative RCT. Studies that focus purely on traumatic RCT are limited in number. A study by Sher et al. found that in patients older than 40 years, asymptomatic tears were common; in contrast to patients younger than 40 years. As such, patients under 40 years of age with RCT, appear to be a different patient population that need to be approached differently to older patients.⁴ The principal difference in RCT between young and old patients may be related to differences in healing potential, etiology of the tear, levels of activity and physical demands, and differing long-term expectations.5, 6, 7

1. Biomechanical consequence of rotator cuff tears

The muscles of the rotator cuff play an important role in normal glenohumeral motion and stability. The supraspinatus acts to initiate abduction, the infraspinatus and teres minor are responsible for external rotation, while the subscapularis is the main internal rotator of the shoulder.⁸ As the rotator cuff muscles act as a force couple with each other and the deltoid, they work together to contain the inherently unstable glenohumeral joint. Massive RCT adversely affect normal shoulder biomechanics. Shoulders with massive traumatic RCT demonstrated an increase in maximum internal rotation in posterosuperior tears, maximum external rotation in anterosuperior tears, and total rotation range of motion at all abduction angles in a cadaveric model compared with the intact state for both.⁸ Disruption of the muscle-tendon units that contribute to active external rotation (infraspinatus and teres minor) leads to weakness in active external rotation and an increase in passive internal rotation, whereas massive RCT involving the subscapularis led to weakness in active internal rotation and increased passive external rotation. These cadaveric findings highlight the important dynamic unloaded effects that the rotator cuff tendons have on glenohumeral kinematics.⁹ To restore normal kinematics in patients with massive traumatic tears of the posterosuperior rotator cuff tendons, greater forces are required by both the deltoid and the intact muscle-tendon units of the rotator cuff, particularly the subscapularis, to achieve stable abduction.¹⁰ The progression of a RCT to disrupt the axial force couple leads to superior subluxation of the humeral head and dysfunction of the shoulder. Pseudo paralysis of the shoulder can occur when the force couple of the glenohumeral joint are disrupted.¹¹ The risk factors for pseudo paralysis are still being investigated; however, a recent study by Collin et al. found disruption of the entire subscapularis or of 3 rotator cuff muscles to be the major risk factors.¹²

2. Mechanism of injury, tear characteristics and tendon involvement

The reported incidence of acute traumatic cuff tears is 8%.¹³ Traumatic tears are thought to stem from higher energy mechanisms and cause full-thickness tears, whereas the natural history of attritional tears is that they originate as partial-thickness tears and perhaps progress to full-thickness tears.¹⁴ Also, traumatic RCT may be larger and more likely to involve the subscapularis. Traumatic subscapularis tear can result from a forced external rotation or hyperextension of the shoulder, or in association with anterior glenohumeral dislocation.¹⁵ Overall, it appears that there are 2 patterns of injury for traumatic tears¹: traumatic RCT in young adults from high energy injuries and² RCT associated with overuse in overhead athletes. Patients with acute traumatic RCT commonly present with symptoms of pain, often localised to the subdeltoid region with loss of function. An inability to elevate the arm on overhead activity after a traumatic event and normal radiographs should raise suspicion, as a high proportion of these injuries can be missed during initial assessment.¹⁶ The supraspinatus is the most commonly involved tendon, as it bears the majority of shoulder-stabilizing strain.¹⁷ Namdari et al., found that 53% of their patients also had an infraspinatus tear.¹⁸ Whereas Ide et al., reported 35% involvement of the infraspinatus in association with supraspinatus tears.¹⁹ Bjornsson et al., in their study revealed that 15 of the 42 (36%) shoulders had a single-tendon tear, of which 14 involved the supraspinatus and 1 the subscapularis. Combined supraspinatus and subscapularis tears were present in 8 patients and combined supraspinatus and infraspinatus tears occurred in 8 patients. Three-tendon tears were present in only 12 patients.²⁰ In a systematic review of traumatic cuff tear outcomes by Mall et al., supraspinatus tears were present in 84%, infraspinatus tears in 39%, and subscapularis tears in 78%.¹⁴

3. Shoulder terrible triad

The Shoulder Terrible Triad (STT) is defined as a traumatic anterior shoulder dislocation, associated with RCT and nerve injury to the brachial plexus branches, which compromises all functional structures of the shoulder.²² They also included displaced greater tuberosity (GT) fractures as they create a discontinuity of the load transfer between the RC and the proximal humerus, similar to a complete traumatic RCT in the setting of a STT. The retrospective cohort study of 30 patients with STT only included patients with first time anterior shoulder dislocation, and those requiring acute surgery for a RCT or a displaced GT fracture.²² In this study, the most frequent injury pattern was a RCT in 83%, an anterior capsular lesion in 63%, and an isolated axillary nerve injury in 70%. No additional anterior glenoid injury repair was undertaken in any of the patients, including the 6% patients that had a Bony Bankart lesion but involving less than 20% glenoid bone loss. At a median follow up of 27 months, repaired RCT correlated with better results than GT fixation, each with a reoperation rate of 20% for RC retear or GT loosening. No patient suffered a recurrent dislocation or residual instability after surgery. All neurological injuries were postganglionic and managed conservatively. All patients in this series showed evidence of partial or full nerve recovery at their last electromyography during follow-up and clinical evidence of a reinnervation process. Irreversible nerve injuries associated with acute shoulder dislocations are uncommon, and most of the nerve injuries recover partially or completely after a post-traumatic interval between 3 and 24 months with reported rates in the literature ranging from 87.5% to 100% of cases.²³

4. Diagnosis

The British Elbow and Shoulder Society (BESS)/British Orthopedic Association (BOA) patient care pathways provide a helpful guide to the clinician. It reiterates the importance of history and examination in the primary care setting, with a useful management algorithm.²⁴ The pathway stresses the significance of being aware of those patients who may have had a trauma to the shoulder with acute pain and weakness, which could be due to an acute rotator cuff tear. In these circumstances an urgent referral to a shoulder specialist should be made and/or consideration of imaging of the rotator cuff. Many patients with suspected acute traumatic tears of RC also have an unexpected abnormality in the subscapularis tendon or an occult fracture of the greater tuberosity.²⁵ Radiographically, occult greater tuberosity fractures and complete subscapularis tears are commonly seen on magnetic resonance images (MRI) in patients suspected of having traumatic tears of the rotator cuff. Greater tuberosity fractures are more likely in patients younger than 40 years, whilst subscapularis tears are more common in patients older than 40 years.²⁵ McCauley looked at the prevalence of bone marrow oedema in the greater tuberosity of the humerus on MRI imaging and the injury mechanism which can lead to this finding. MRI reports from 863 patients over 74 months were reviewed to identify patients with marrow oedema in the greater tuberosity.²⁶ Most patient with this finding had a history of a prior fall, but without a direct blow to the greater tuberosity. This history suggests the marrow oedema in the greater tuberosity is likely due to avulsion force rather than direct impact. The lack of oedema in the overlying soft tissue further supports this hypothesis. The presence of rotator cuff injuries in most patients could be explained by avulsion forces generated by contraction of the supraspinatus muscle during a fall causing greater tuberosity avulsion injury. Avulsion forces generated by supraspinatus tendon have been previously described as a mechanism of rotator cuff injury.^25,27,28 Similar findings have been reported in a study by Mason et al.²⁸ In conclusion, marrow oedema in the greater tuberosity is an infrequent finding on MRI imaging of the shoulder. In most patients with oedema in the greater tuberosity there is a history of trauma and most patients have rotator cuff abnormalities including partial and full thickness tears. The history of trauma without direct blow to the shoulder and the location of the oedema indicates that marrow oedema often results from avulsion injury by the supraspinatus tendon.²⁶

5. Treatment options and clinical outcomes

5.1. Nonoperative management

Nonoperative management with physiotherapy remains a cornerstone in the management of RCT. Shoulder pain and function after RC repair, or physiotherapy without surgical repair of small-to medium-sized RC tears have been investigated in a few prospective randomized studies.29, 30, 31, 32 These studies have shown no difference,³⁰ or slightly better outcome following a surgical repair.^29,32 These differences have been below or on the thresholds for clinical importance. However, the majority of studies have included only degenerative, nontraumatic tears.^29,32 A prospective randomized study focusing exclusively on traumatic cuff tears by Ranebo et al., shows that small full-thickness RCT, treated either with operative repair or physiotherapy without repair can result in good or satisfactory outcome in a majority of patients at the 1-year follow-up.³³ Though, operative repair resulted in slightly higher Constant Score (CS) and Western Ontario Rotator Cuff (WORC) score, the differences were neither clinically nor statistically significant. There were no significant differences in pain or quality of life between the 2 groups; 29% of unrepaired tears had increased in tear size >5 mm during the observation period.³³

5.2. Rotator cuff repair and surgical timing

The goal of repairing a traumatically injured rotator cuff is to restore biomechanics of the shoulder. This in turn should result in outcomes of reduced pain and improved function. Repair should be undertaken with a fixation device that would allow aggressive rehabilitation process.^34,35 Complete anatomic repair, when reasonable, should be performed.

Healing continues to be a major focus in rotator cuff surgery, with surgeons and researchers attempting to determine the best milieu to allow tendon to bone healing. Healing has been consistently shown to dramatically affect outcomes.¹⁵

Healing rates for traumatic tears should theoretically be improved as it often involves younger patients. Early repair should also result in favorable outcome as retraction and muscle atrophy as not set in and have a favorable biological environment for tendon healing with ongoing inflammatory response. Mall et al. showed in his story the poor outcomes related to delayed diagnosis and surgery as a result of retraction, fatty infiltration and tendon retraction.³⁶ The proportion of muscle fatty infiltration increases with the degree of musculotendinous retraction, and early surgery has been recommended to prevent tendon retraction and preserve tissue quality.³⁷

Spross et al., have shown that acute pseudo-paralysis following massive traumatic cuff tear can reliably be reversed with early arthroscopic repair.³⁸

Gerber et al. reported improved outcomes in the 13 patients who underwent surgery within 20 months of injury as compared to the 3 patients whose surgeries were delayed more than 36 months after injury.¹⁵ Petersen and Murphy noted that surgical repairs performed within 16 weeks from injury were associated with a significantly improved range of motion and outcome scores, compared to those performed later than 16 weeks.³⁹ Bassett and Cofield determined that traumatic cuff tears repaired within 3 weeks had a significantly better forward elevation and a trend towards better strength in both abduction and external rotation than those repaired after 3 weeks.¹³ However, Bjornson et al. found no difference in healing, Constant Score, DASH score, or WORC index with respect to time to repair.²⁰ Millett et al. recently conducted a meta-analysis of level I randomized clinical trials comparing arthroscopic single-row vs. double-row rotator cuff repair.⁴⁰ They found that single-row repairs had a significantly higher retear rates compared with double-row repairs, especially with regard to partial-thickness retears, although, they were not able to detect a difference in an improvement in outcome scores between single-row and double-row repairs.⁴⁰ They also reported failure rates as low as 7% in small tears <1 cm and upward of 69% retears in larger tear.⁴⁰

5.3. Outcome following early cuff repair

Most studies show a significant improvement from preoperative to postoperative values for the respective outcome’s measures used. In cases with early cuff repair. Namdari et al. reported postoperative DASH and Constant scores (CS) of 12.2 and 93.4.¹⁸ Ide et al. reported good results using UCLA score 31.1 in the acute repair group.¹⁹ Petersen and Murphy reported good outcome with early repair on UCLA score.³⁹ Gerber et al. in his study of isolated subscapularis repair reported significant improvement on CS to 95.¹⁵ Lahteenmaki et al. noted a significant improvement postoperatively with 30.6 overall score on UCLA.⁴¹ Hantes et al. reported significantly better Constant and UCLA scores when comparing acute repair versus delayed repair.⁴² (Table 1).

Table 1.

Clinical outcomes.

Study	Constant Score	VAS Score	UCLA Score	DASH	Active Forward Flexion	Active External Rotation
Gerber et al. (1996)	59 (preop) to 95	NR	NR	NR	NR	NR
Braune et al. (2003)	Group 1: 94.1 (acute repair) Group 2: 75.3 (delayed repair)	Group 1: 20 (7–10) Group 2: 13 (7–10), 7 (5-6), 6 (<5)	NR	NR	Group I: 166 Group II: 156	Group 1: 56 Group 2: 38
Lahteenmaki et al. (2006)	NR	NR	Pain: 1.8 (preop) to 8.3 Function: 1.8–8.6 Strength: 2.7–4.4 Satisfied 239/unsatisfied 7 Overall score: 30.6	NR	Small tear: 130-160 Medium tear: 112-153	Small tear: 62-61 Medium tear: 60-54
Namdari et al. (2008)	93.4	6.2–1.2	NR	41.7–12.2	81–97	93–109
Ide et al. (2007)	NR	NR	14.9–31.1	NR	97–162	30-43 (internal rotation: L-2 to T-10)
Hantes et al. (2011)	Group 1: 39-82 Group 2: 40-70	NR	Group I: 10-31 Group 2: 12-27	NR	NR	NR
Petersen and Murphy (2011)	NR	7–1.4	Group 1: 6-30 Group 2: 9-30 Group 3: 9-25		Group 1: 54-137 Group 2: 52-142 Group 3: 66-100	39–49

Note: VAS, visual analog scale; UCLA, University of California, Los Angeles; DASH, Disabilities of the Arm, Shoulder, and Hand score.

6. Discussion

Traumatic cuff tears demonstrate a particular need for careful management, given the potential for both short- and long-term disability if the tears are not appropriately managed. Especially in cases of acute trauma, early surgical treatment is generally recommended as delays are associated with tendon retraction, atrophy of muscles, and generally poor surgical outcome^12,14,17 RCT in patients younger than 40 years are of traumatic origin and respond well to both arthroscopic and open rotator cuff repair in terms of pain relief and self-reported outcomes postoperatively; patients report high levels of satisfaction. Patients who experience a traumatic rotator cuff tear are categorically different from those who experience a nontraumatic degenerative type of tear. These patients are more active, sustained more violent mechanism of injury and this results in large full thickness tear or even massive rotator cuff tear involving more than one tendon. The subscapularis tendon is also more likely to be involved. Tendon healing in traumatic tears is improved when repaired early. In the current available literature, there is no indication that acute repair in traumatic injuries produces better outcomes; however, this may be related to the difficulty in differentiating an acute on chronic tear from a definitively acute, traumatic tear. Further research is needed to directly compare the results of acute intervention for patients who present with traumatic RCT.

Source of funding statement

None.

Declaration of competing interest

None.