Rotator Cuff Tear
What is it?
What is the cause?
Pain referral pattern:
Diagnostic tool to rule in/out:
- A tear in one of the four rotator cuff muscles. Three which insert into the greater tuberosity ( supraspinatus, infraspinatus, teres minor) and one to the lesser tuberosity ( subscapularis). The incidence of cuff tears in patients who are more than 60 years old has been reported as high as 40%, and not all these patients are symptomatic
What is the cause?
- Rotator cuff tear is thought to be a result of degenerative decline of the rotator cuff muscles and or trauma(repeated microtrauma or severe acute trauma) to the involved shoulder. There can also be secondary causes such as narrowing of subacromial space or bony anomalies. Codman found that majority of tears happen at the greater tuberosity of the proximal humerus because it is hypovascular and subject to degenerative changes over time. Reduction in subacromial space has been shown to cause degenerative changes that lead to rotator cuff tears.
- Patients with rotator cuff tears frequently have less shoulder range of motion actively than passively because of weakness. Patients with massive tears have weakness in the supraspinatus and infraspinatus, and because if the teres is involved, they will not be able to hold the arm in the 90/90-degree position in maximal external rotation with a massive tear. Night pain and weakness are associated with tendon tears.
Pain referral pattern:
- A patient who has a cuff tear, C5 root involvement may produce biceps weakness, and this may be a distinguishing feature.
Diagnostic tool to rule in/out:
- Patients with massive cuff tears often use accessory muscles to elevate their arms. A common physical finding is the shrug sign, in which the patient activates the trapezius and deltoid when attempting forward elevation
- X- rays can be used to for chronic large tears of the rotator cuff distinguished and the greater tuberosity. If it's not confirmed with an X-ray an MRI can be used to distinguish a tear
- Painful arc has been associated with supraspinatus tear of the supraspinatus with a .33- .74 sensitivity and .79-.81 specificity.
- Drop arm test is associated with a full supraspinatus tear with a .27 sensitivity and .86 specificity.
- Kukkonen et al. found that there is a positive correlation with tear size and recovery time. The bigger tears with in the specific rotator cuff muscles resulted in longer recovery or rehab time.