Quick answer: A rotator cuff tear can happen suddenly from an injury (an acute traumatic tear) or develop slowly as the tendon wears down with age (a chronic degenerative tear). Degenerative tears are very common, are often painless and usually start with physical therapy [2–4, 15]. Traumatic tears tend to be larger and cause sudden weakness [5]. When one happens in an active person, a prompt evaluation matters, because studies suggest the best results come when the tendon is repaired within the first few months after the injury [9–11].
What Is the Rotator Cuff?
The rotator cuff is a group of four muscles and their tendons that wrap around the ball of the shoulder. They keep the ball centered in the socket and help lift and rotate the arm. A tear means one or more of these tendons has pulled partly or completely away from the bone [1].
Two Different Ways a Tendon Tears
Chronic degenerative tears
Most rotator cuff tears are not caused by a single injury. The tendon thins and frays gradually over years, and tears become more common with each decade of life:
- In an ultrasound study of more than 1,300 shoulders in the general population, about 1 in 5 had a full-thickness tear. Age, use of the dominant arm and a history of injury were the main risk factors [2].
- Among people with no shoulder pain at all, tears were found in 13% of those in their 50s and in 51% of those over 80 [3].
- In an MRI study of people without symptoms, 54% of those over 60 had a tear [4].
In other words, many degenerative tears are painless and part of normal aging. For more on how common tears are and how often they grow, see How Common Are Rotator Cuff Tears, and Do They Get Worse Without Surgery? Symptoms usually build slowly: an ache on the side of the arm, pain at night and difficulty reaching overhead.
Acute traumatic tears
An acute tear happens at a specific moment, most often from:
- A fall onto an outstretched arm, the most common cause [5]
- A shoulder dislocation, especially in people over 40 [8]
- Catching a heavy object, a sudden forceful pull, or lifting something heavy with the arm away from the body
Patients usually remember the exact moment. Typical symptoms are sudden pain, sometimes a tearing sensation, and new weakness: trouble lifting the arm, or not being able to raise it at all.
In a systematic review of traumatic tears, patients averaged about 55 years old. The tears were often large: 42% were over 5 cm, and the subscapularis tendon at the front of the shoulder was involved in 78% [5]. In patients under 40, most full-thickness rotator cuff tears are traumatic, while overhead throwing athletes are the exception and more often have partial tears from repetitive overuse [6].
"Acute-on-chronic" tears
Some injuries happen to a tendon that was already worn. A person with a small, painless degenerative tear may fall and suddenly lose strength because the tear has extended. Telling these apart from a purely new injury is important, because the old part of the tear may already show muscle changes that affect the repair.
Side-by-Side Comparison
| Acute traumatic tear | Chronic degenerative tear | |
|---|---|---|
| How it starts | A specific injury: fall, dislocation, sudden pull | Gradual; often no injury |
| Typical age | Any adult, including younger, active patients [5, 6] | More common after 50, increasing with age [2–4] |
| Main symptom | Sudden pain and new weakness | Slowly building pain, especially at night |
| Tear size | Often large; may involve several tendons [5] | Varies; often begins small and can slowly enlarge |
| MRI clues | Muscle swelling (edema), a wavy "kinked" tendon [7] | Muscle shrinkage (atrophy) and fatty change [7] |
| Usual first step | Prompt specialist evaluation and MRI | Physical therapy for most patients [15, 16] |
| Is timing important? | Yes. Earlier repair is linked to better results [9–11] | Less urgent, but tears can grow over time [16] |
How Is the Difference Diagnosed?
The story of how the pain began is the most important clue, along with an exam of strength in each direction. X-rays look for fractures and arthritis but cannot show the tendon.
An MRI helps tell the two apart. In a study comparing patients injured within the previous 6 weeks with patients who had gradual pain and no injury [7]:
- Muscle edema (swelling) was more common in traumatic tears (37.5% vs. 4%).
- A wavy, "kinked" tendon end was more common in traumatic tears (64% vs. 32%).
- Muscle atrophy was more common in degenerative tears (60% vs. 29%).
No single finding was definitive, so the MRI is read together with the history and exam [7].
A practical point: after a shoulder dislocation, a patient over 40 who still cannot lift the arm a few weeks later should be checked for a rotator cuff tear. Patients with ongoing pain or weakness after a dislocation often have one, and repair gave better pain relief and satisfaction than nonsurgical care in the studies reviewed [8].
Why Timing Matters for Traumatic Tears
Once a tendon tears away from the bone, it begins to pull back (retract), and over the following months its muscle can shrink and fill with fat. These muscle changes generally do not reverse after repair and are linked to poorer function [14]. This is why traumatic tears, especially large ones, are evaluated promptly.
The research on timing:
- In an early study of acute tears, patients repaired within 3 weeks regained the most overhead motion [9].
- In a prospective study of painful traumatic tears with weakness, results were not compromised as long as the tear was repaired within 4 months. Massive tears repaired after 4 months had the worst results [10].
- In a study of 206 traumatic tears, repair within 4 months of the injury was linked to better function scores and less pain than later repair [11].
Not every study agrees. One smaller study found no difference between repair within 6 months and later repair [12], and a systematic review concluded that the evidence was not strong enough to firmly recommend early surgery for every traumatic tear [5]. The overall message is that a traumatic tear should be evaluated promptly so that a decision can be made while all options remain open, not that every tear needs urgent surgery.
Does Every Traumatic Tear Need Surgery?
No. In a randomized trial of small traumatic supraspinatus tears (about 1 cm) in patients averaging 60 years old, surgery and physiotherapy gave similar results at one year. However, about one-third of the tears treated without surgery had grown by more than 5 mm [13]. So for a small traumatic tear, therapy with follow-up imaging can be reasonable, with repair if the tear enlarges or strength does not return.
Surgery is more often recommended when:
- The tear is full-thickness and large, or involves more than one tendon
- There is significant weakness, or the arm cannot be raised
- The patient is younger or physically active, or works with the arm
- The tear followed a dislocation and the shoulder remains painful or weak [8]
How Chronic Degenerative Tears Are Usually Treated
For tears without a clear injury, a structured program of physical therapy is usually the first step. In a large multicenter study of atraumatic full-thickness tears, about 75% of patients treated with therapy avoided surgery over two years [15]. In a randomized trial of nontraumatic tears, therapy alone and repair gave similar results at two years, although unrepaired tears were more likely to enlarge [16].
Surgery is considered when pain and function don't improve with therapy, when weakness develops, or when imaging shows the tear is getting larger. For more on this decision, see Rotator Cuff Tear: Surgery vs. Physical Therapy.
Recovery
Recovery after repair is similar for both types of tear: a sling for several weeks, gradual motion, and then strengthening, with full recovery often taking 6 months or more. In younger patients with traumatic tears, repair improved pain and strength in nearly all studies and 87% of patients were satisfied [6]. See the Rotator Cuff Repair Recovery Timeline for a month-by-month guide.
When to See a Shoulder Specialist
See a shoulder specialist promptly if, after a fall, dislocation or lifting injury:
- You cannot lift your arm away from your side or overhead
- You have new weakness that is not improving after a week or two
- Your shoulder dislocated and you are over 40, or it still hurts or feels weak weeks later
- You had a mild ache before, but the injury made it suddenly much worse
For gradual pain without an injury, an evaluation is reasonable if pain lasts more than a few weeks, keeps you up at night or does not improve with therapy. Learn more about rotator cuff tears and rotator cuff repair.
Dr. Tej Joshi sees patients with shoulder injuries in Manhattan, Bay Ridge, Brooklyn and Lake Success, Long Island. Request an appointment.
FAQs
How do I know if my rotator cuff tear is from an injury or from wear and tear? The most important clue is how it started. A sudden onset with new weakness after a fall or lift points toward a traumatic tear. An MRI can add clues, such as muscle swelling or a wavy tendon in recent injuries and muscle shrinkage in older tears [7].
How soon should a traumatic rotator cuff tear be repaired? When surgery is recommended, studies suggest results are best when the tear is repaired within about 3 to 4 months of the injury, and some found the best motion with repair within 3 weeks [9–11]. The first step is a prompt evaluation so the timing can be planned.
Can an acute rotator cuff tear heal on its own? A full-thickness tear does not reattach to the bone on its own. Symptoms can improve with therapy, especially for small tears, but some tears enlarge over time [13].
I had a rotator cuff tear on MRI but no pain. Do I need surgery? Usually not. Tears are common in people without symptoms, especially after age 60 [3, 4]. Treatment is based on symptoms and function, not the MRI alone.
Can a shoulder dislocation tear the rotator cuff? Yes, particularly in patients over 40. Persistent pain or weakness after a dislocation should be checked for a rotator cuff tear [8].
References
- American Academy of Orthopaedic Surgeons. Rotator Cuff Tears. OrthoInfo. orthoinfo.org
- Yamamoto A, Takagishi K, Osawa T, et al. Prevalence and risk factors of a rotator cuff tear in the general population. J Shoulder Elbow Surg. 2010;19(1):116-20. PubMed 19540777 · doi:10.1016/j.jse.2009.04.006
- Tempelhof S, Rupp S, Seil R. Age-related prevalence of rotator cuff tears in asymptomatic shoulders. J Shoulder Elbow Surg. 1999;8(4):296-9. PubMed 10471998 · doi:10.1016/s1058-2746(99)90148-9
- Sher JS, Uribe JW, Posada A, et al. Abnormal findings on magnetic resonance images of asymptomatic shoulders. J Bone Joint Surg Am. 1995;77(1):10-5. PubMed 7822341 · doi:10.2106/00004623-199501000-00002
- Mall NA, Lee AS, Chahal J, et al. An evidenced-based examination of the epidemiology and outcomes of traumatic rotator cuff tears. Arthroscopy. 2013;29(2):366-76. PubMed 23290186 · doi:10.1016/j.arthro.2012.06.024
- Lazarides AL, Alentorn-Geli E, Choi JH, et al. Rotator cuff tears in young patients: a different disease than rotator cuff tears in elderly patients. J Shoulder Elbow Surg. 2015;24(11):1834-43. PubMed 26209913 · doi:10.1016/j.jse.2015.05.031
- Loew M, Magosch P, Lichtenberg S, et al. How to discriminate between acute traumatic and chronic degenerative rotator cuff lesions: an analysis of specific criteria on radiography and magnetic resonance imaging. J Shoulder Elbow Surg. 2015;24(11):1685-93. PubMed 26234668 · doi:10.1016/j.jse.2015.06.005
- Gombera MM, Sekiya JK. Rotator cuff tear and glenohumeral instability: a systematic review. Clin Orthop Relat Res. 2014;472(8):2448-56. PubMed 24043432 · doi:10.1007/s11999-013-3290-2
- Bassett RW, Cofield RH. Acute tears of the rotator cuff. The timing of surgical repair. Clin Orthop Relat Res. 1983;(175):18-24. PubMed 6839586
- Petersen SA, Murphy TP. The timing of rotator cuff repair for the restoration of function. J Shoulder Elbow Surg. 2011;20(1):62-8. PubMed 20675154 · doi:10.1016/j.jse.2010.04.045
- Gutman MJ, Joyce CD, Patel MS, et al. Early repair of traumatic rotator cuff tears improves functional outcomes. J Shoulder Elbow Surg. 2021;30(11):2475-2483. PubMed 33774173 · doi:10.1016/j.jse.2021.03.134
- de Sa R, Hassan A, Soliman E, et al. Traumatic rotator cuff injury: does delayed surgery worsen functional outcomes? Int Orthop. 2024;48(5):1271-1275. PubMed 38403732 · doi:10.1007/s00264-024-06127-2
- Ranebo MC, Björnsson Hallgren HC, Holmgren T, et al. Surgery and physiotherapy were both successful in the treatment of small, acute, traumatic rotator cuff tears: a prospective randomized trial. J Shoulder Elbow Surg. 2020;29(3):459-470. PubMed 31924516 · doi:10.1016/j.jse.2019.10.013
- Gladstone JN, Bishop JY, Lo IK, Flatow EL. Fatty infiltration and atrophy of the rotator cuff do not improve after rotator cuff repair and correlate with poor functional outcome. Am J Sports Med. 2007;35(5):719-28. PubMed 17337727 · doi:10.1177/0363546506297539
- Kuhn JE, Dunn WR, Sanders R, et al. Effectiveness of physical therapy in treating atraumatic full-thickness rotator cuff tears: a multicenter prospective cohort study. J Shoulder Elbow Surg. 2013;22(10):1371-9. PubMed 23540577 · doi:10.1016/j.jse.2013.01.026
- Kukkonen J, Joukainen A, Lehtinen J, et al. Treatment of nontraumatic rotator cuff tears: a randomized controlled trial with two years of clinical and imaging follow-up. J Bone Joint Surg Am. 2015;97(21):1729-37. PubMed 26537160 · doi:10.2106/JBJS.N.01051