Difference between revisions of "Posterosuperior Rotator Cuff Tears and Associated Pathologies"

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(Created page with "==Bullet Points== Despite advances in surgical reconstruction of chronic rotator cuff tears leading to improved clinical outcomes, failure rates of 13-94% have been reported....")
 
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==Bullet Points==
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== Bullet Points ==
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Despite advances in surgical reconstruction of chronic rotator cuff tears leading to improved clinical outcomes, failure rates of 13-94% have been reported. Reasons for this rather high failure rate include compromised healing at the bone-tendon interface, as well as the musculotendinous changes that occur after RC tears, namely retraction and muscle atrophy, as well as fatty infiltration.
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* The rotator cable explains why patients with most rotator cuff tears can maintain active forward flexion, and also why even after only a partial rotator cuff repair, good functional results can be achieved.
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It is important to note that instead of a physiological enthesis, an abundance of scar tissue is formed during healing process.
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* The most important negative prognostic factor is high-grade fatty infiltration of the rotator cuff muscle bellies (grade 3 or 4 fatty infiltration).
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Even though cytokines have demonstrated the potential to improve rotator cuff healing in animal models, there is little information about the correct concentration and timing of the more than 1500 cytokines that interact during the healing process.
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* The tangent sign is an indicator of advanced fatty infiltration and is a predictor of whether a rotator cuff tear will be reparable.
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There is only minimal evidence that platelet concentrates may lead to improvement in radiographic, but not clinical outcome.
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* Full thickness disruption of the lateral tendon stump (B1) is the most frequent type of rotator cuff lesion, comprising approximately 90% of all surgically treated lesions.
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Using stem cells to biologically augment the reconstruction of the tears might have a great potential since these cells can differentiate into various cell types that are integral for healing.
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* Musculotendinous junction lesions (C-type) or rare and characterized by an edema of the muscle belly. They are associated to calcific deposit (infraspinatus) or trauma (supraspinatus). Unrepaired, grade III lesions lead rapidly to grade 4 fatty infiltration of the muscle.
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* Tendon retraction is classified according to Patte. Overreduction and lateral transposition of the tendon over the greater tuberosity may be unphysiological.
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* Massive rotator cuff has different definitions in the literature, each having potential benefits or drawbacks.
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* Massive rotator cuff tears comprise approximately 20% of all cuff tears and 80% of recurrent tears.
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* The classification of Collin not only subclassifies massive tears but has also been linked to function, particularly the maintenance of active elevation.
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* Non-surgical treatment is effective in patient with massive rotator cuff if the tear involves less than three tendons and do not involves the subscapularis (D-type).
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* Biomechanical testing has consistently demonstrated the superiority of double-row constructs over single-row. However, there is no obvious difference clinically.
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* There is actually no support for routine suprascapular nerve release when massive rotator cuff repair is performed.
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* Functional outcome improved after revision rotator cuff repair and 70% or more of patients were satisfied or very satisfied. However, the prevalence of persistent defect (retear or non-healing) is 28% at six months and 40% at two years.
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* Rotator cuff are irreparable when associated to true pseudoparalysis with the presence of lag signs (external rotation lag, drop, dropping, hornblower signs), femoralization of the humerus or acetabulization of the acromion, grade 3 or 4 fatty infiltration and tangent sign.
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* The current literature does not support the initial use of complex and expensive techniques in the management of posterosuperior irreparable rotator cuff tears.
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== Key Words ==
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Shoulder arthroscopy; Rotator cuff lesion; Partial repair; Tear pattern; Classification; Massive; Reparable and non-repairable; Irreparable; Imaging; Recurrent; Failed; Revision surgery; Open and arthroscopic approach; Conservative or non-operative treatment; Physiotherapy; Functional outcomes; Prognostic factors; Latissimus dorsi transfer; Subacromial spacer interposition; Balloon; Biceps tenotomy; Superior capsular reconstruction; Reverse arthroplasty; Magnetic resonance imaging (MRI) arthrography (MRA); Fosbury flop tear; New tear pattern; FUSSI; SAM.
  
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==Key Words==
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Biomechanics of the Posterosuperior Rotator Cuff
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Biological augmentation, Rotator cuff healing, Stem cells, Growth factors, Scaffolds, Shoulder surgery, Platelet rich fibrin, Platelet concentrates, Mesenchymal stem cells, Fatty infiltration, Atrophy, Retraction.
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A primary function of the rotator cuff is to work synergistically with the deltoid to maintain a balanced force couple about the glenohumeral joint. A force couple is a pair of forces that act on an object and tend to cause it to rotate. For any object to be in equilibrium, the forces must create moments about a center of rotation that are equal in magnitude and opposite in direction. Coronal and transverse plane force couples exist between the subscapularis anteriorly and infraspinatus and teres minor posteriorly. The rotator cuff force across the glenoid provides concavity compression, which creates a stable fulcrum and allows the periscapular muscles to move the humerus around the glenoid.
  
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==Introduction==
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The rotator cable is a thickening of the rotator cuff that has been likened to a suspension bridge in which force is distributed through cables that are supported by pillars (the anterior and posterior attachments). The anterior rotator cable attachment bifurcates to attach to bone just anterior and posterior to the proximal aspect of the bicipital groove. The posterior attachment comprises the inferior 50% of the infraspinatus. With small central tears the cable attachments often stay intact and forces are transmitted along the rotator cable. The rotator cable also explains why patients with most rotator cuff tears can maintain active forward flexion, and also why even after only a partial rotator cuff repair, good functional results can be achieved.
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Pathologies of the rotator cuff are by far the most common cause of shoulder dysfunction and pain. In the presence of full thickness rotator cuff tears, rotator cuff reconstruction is a commonly performed surgical solution. Even though rotator cuff repair results in improved clinical outcome, several studies report failure of healing in up to 94% of patients.<ref>Galatz LM, Ball CM, Teefey SA, Middleton WD, Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J bone Joint Surg Am 2004;86-A(2):219-24.</ref>
 
  
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The reason for these high failure rates may be due to intrinsic degenerative changes of the musculotendinous unit. Subsequent to a tear, the muscle retracts, but this muscular retraction is significantly less then the degree of tendon retraction that occurs at later stages.<ref>Kuenzler MB, Nuss K, Karol A, Schär MO, Hottiger M, Raniga S, Kenkel D, von Rechenberg B, Zumstein MA. Neer Award 2016: reduced muscle degeneration and decreased fatty infiltration after rotator cuff tear in a poly(ADP-ribose) polymerase 1 (PARP-1) knock-out mouse model. J Shoulder Elbow Surg. 2017 May;26(5):733-744</ref><ref>Lädermann A, Zumstein M, Kolo F, Grosclaude M, Koglin L, Schwitzguebel A. In Vivo Clinical and Radiological Effects of Platelet-rich Plasma on Interstitial Supraspinatus Lesion: Case Series. Orthop Traumatol Surg Res. 2016 Dec;102(8):977-982.</ref><br>
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1. Burkhart SS, Nottage WM, Ogilvie-Harris DJ, Kohn HS, Pachelli A. Partial repair of irreparable rotator cuff tears. Arthroscopy 1994;10:363-70.
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In the tendon low cellularity, degenerative changes and poor blood supply of the enthesis are significant in the findings. Whilst in the muscle, there is significant migration of inflammatory cells within the first few days of a tear and the muscle fibers undergo apoptosis. In the ensuing weeks to months, this early response leads to muscular retraction, degeneration and atrophy. The progressive loss of muscle volume is due to a loss of sarcomeres in series that is associated with an increase in pennation angle which causes an enlargement of the inter- and intramyofibrillar spaces. If the muscle remains unloaded and retracted, the myogenic precursor cells may be reprogrammed into the adipogenic pathway, with mature adipocytes infiltrating the free inter- and intramyofibrillar spaces. This phenomenon is termed fatty infiltration.<ref>Lundgreen K, Lian OB, Engebretsen L, Scott A. Tenocyte apoptosis in the torn rotator cuff: a primary or secondary pathological event? Br J Sports Med. 2011;45(13):1035-9.</ref>
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However, in the setting of massive rotator cuff with rotator cable disruption and non-compensation by other humeral head stabilizers (i.e pectoralis major and latissimus dorsi), the moments created by the opposing muscular forces are insufficient to maintain equilibrium in the coronal plane, resulting in altered kinematics, instability, and ultimately in pseudoparalysis. Interestingly, only few patients with an irreparable rotator cuff tears developed pseudoparalysis and arthritis.This finding has at least two potential explanations. First, the subscapularis that may not be involved in these tears is the key factor of active forward flexion.
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2. Collin P, Matsumura N, Lädermann A, Denard PJ, Walch G. Relationship between massive chronic rotator cuff tear pattern and loss of active shoulder range of motion. J Shoulder Elbow Surg 2014;23:1195-202.
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Second, the rotator cable, has still an intact anterior attachment which is important for elevation. This may explain why patients can maintain active mobility, and also why even after only a partial rotator cuff repair, good functional results can be achieved.
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3. Denard PJ, Lädermann A, Brady PC, et al. Pseudoparalysis From a Massive Rotator Cuff Tear Is Reliably Reversed With an Arthroscopic Rotator Cuff Repair in Patients Without Preoperative Glenohumeral Arthritis. Am J Sports Med 2015;43:2373-8.
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Consequently, all the conditions for an imbalance in the force couples are not always met and subsequently loss of function is only occasionally seen.
  
 
==References==
 
==References==
 
<references />
 
<references />

Revision as of 15:48, 2 January 2020

Bullet Points

  • The rotator cable explains why patients with most rotator cuff tears can maintain active forward flexion, and also why even after only a partial rotator cuff repair, good functional results can be achieved.
  • The most important negative prognostic factor is high-grade fatty infiltration of the rotator cuff muscle bellies (grade 3 or 4 fatty infiltration).
  • The tangent sign is an indicator of advanced fatty infiltration and is a predictor of whether a rotator cuff tear will be reparable.
  • Full thickness disruption of the lateral tendon stump (B1) is the most frequent type of rotator cuff lesion, comprising approximately 90% of all surgically treated lesions.
  • Musculotendinous junction lesions (C-type) or rare and characterized by an edema of the muscle belly. They are associated to calcific deposit (infraspinatus) or trauma (supraspinatus). Unrepaired, grade III lesions lead rapidly to grade 4 fatty infiltration of the muscle.
  • Tendon retraction is classified according to Patte. Overreduction and lateral transposition of the tendon over the greater tuberosity may be unphysiological.
  • Massive rotator cuff has different definitions in the literature, each having potential benefits or drawbacks.
  • Massive rotator cuff tears comprise approximately 20% of all cuff tears and 80% of recurrent tears.
  • The classification of Collin not only subclassifies massive tears but has also been linked to function, particularly the maintenance of active elevation.
  • Non-surgical treatment is effective in patient with massive rotator cuff if the tear involves less than three tendons and do not involves the subscapularis (D-type).
  • Biomechanical testing has consistently demonstrated the superiority of double-row constructs over single-row. However, there is no obvious difference clinically.
  • There is actually no support for routine suprascapular nerve release when massive rotator cuff repair is performed.
  • Functional outcome improved after revision rotator cuff repair and 70% or more of patients were satisfied or very satisfied. However, the prevalence of persistent defect (retear or non-healing) is 28% at six months and 40% at two years.
  • Rotator cuff are irreparable when associated to true pseudoparalysis with the presence of lag signs (external rotation lag, drop, dropping, hornblower signs), femoralization of the humerus or acetabulization of the acromion, grade 3 or 4 fatty infiltration and tangent sign.
  • The current literature does not support the initial use of complex and expensive techniques in the management of posterosuperior irreparable rotator cuff tears.

Key Words

Shoulder arthroscopy; Rotator cuff lesion; Partial repair; Tear pattern; Classification; Massive; Reparable and non-repairable; Irreparable; Imaging; Recurrent; Failed; Revision surgery; Open and arthroscopic approach; Conservative or non-operative treatment; Physiotherapy; Functional outcomes; Prognostic factors; Latissimus dorsi transfer; Subacromial spacer interposition; Balloon; Biceps tenotomy; Superior capsular reconstruction; Reverse arthroplasty; Magnetic resonance imaging (MRI) arthrography (MRA); Fosbury flop tear; New tear pattern; FUSSI; SAM.

Biomechanics of the Posterosuperior Rotator Cuff A primary function of the rotator cuff is to work synergistically with the deltoid to maintain a balanced force couple about the glenohumeral joint. A force couple is a pair of forces that act on an object and tend to cause it to rotate. For any object to be in equilibrium, the forces must create moments about a center of rotation that are equal in magnitude and opposite in direction. Coronal and transverse plane force couples exist between the subscapularis anteriorly and infraspinatus and teres minor posteriorly. The rotator cuff force across the glenoid provides concavity compression, which creates a stable fulcrum and allows the periscapular muscles to move the humerus around the glenoid.

The rotator cable is a thickening of the rotator cuff that has been likened to a suspension bridge in which force is distributed through cables that are supported by pillars (the anterior and posterior attachments). The anterior rotator cable attachment bifurcates to attach to bone just anterior and posterior to the proximal aspect of the bicipital groove. The posterior attachment comprises the inferior 50% of the infraspinatus. With small central tears the cable attachments often stay intact and forces are transmitted along the rotator cable. The rotator cable also explains why patients with most rotator cuff tears can maintain active forward flexion, and also why even after only a partial rotator cuff repair, good functional results can be achieved.

1. Burkhart SS, Nottage WM, Ogilvie-Harris DJ, Kohn HS, Pachelli A. Partial repair of irreparable rotator cuff tears. Arthroscopy 1994;10:363-70. However, in the setting of massive rotator cuff with rotator cable disruption and non-compensation by other humeral head stabilizers (i.e pectoralis major and latissimus dorsi), the moments created by the opposing muscular forces are insufficient to maintain equilibrium in the coronal plane, resulting in altered kinematics, instability, and ultimately in pseudoparalysis. Interestingly, only few patients with an irreparable rotator cuff tears developed pseudoparalysis and arthritis.This finding has at least two potential explanations. First, the subscapularis that may not be involved in these tears is the key factor of active forward flexion.

2. Collin P, Matsumura N, Lädermann A, Denard PJ, Walch G. Relationship between massive chronic rotator cuff tear pattern and loss of active shoulder range of motion. J Shoulder Elbow Surg 2014;23:1195-202. Second, the rotator cable, has still an intact anterior attachment which is important for elevation. This may explain why patients can maintain active mobility, and also why even after only a partial rotator cuff repair, good functional results can be achieved.

3. Denard PJ, Lädermann A, Brady PC, et al. Pseudoparalysis From a Massive Rotator Cuff Tear Is Reliably Reversed With an Arthroscopic Rotator Cuff Repair in Patients Without Preoperative Glenohumeral Arthritis. Am J Sports Med 2015;43:2373-8. Consequently, all the conditions for an imbalance in the force couples are not always met and subsequently loss of function is only occasionally seen.

References

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