What Are the Symptoms and Treatment for a Partial Thickness Tear?

A partial-thickness rotator cuff tear produces shoulder pain that worsens with overhead activity and often disturbs sleep, along with weakness and restricted range of motion. Treatment usually starts with physical therapy and targeted exercises, with injections or surgery reserved for tears that do not respond or that involve more than half the tendon’s thickness. The condition is remarkably common and does not always require an aggressive intervention, but understanding the specifics of how these tears behave, how they are diagnosed, and when they need more than conservative care matters for making good decisions about your shoulder.

What a Partial-Thickness Tear Actually Is

Your rotator cuff is a group of four tendons that wrap around the head of your upper arm bone and hold it snugly in the shoulder socket. A partial-thickness tear means that only part of the tendon’s depth is damaged, as opposed to a full-thickness tear, where the tendon is torn all the way through. Think of it like a frayed rope: some fibers are snapped, but the rope is still in one piece. The supraspinatus tendon, which sits on top of the shoulder, is by far the most frequently affected, accounting for the majority of isolated rotator cuff tendon injuries.

Tears are graded by how much of the tendon’s thickness is involved. The most common classification uses three grades: grade I involves less than a quarter of the thickness, grade II involves less than half, and grade III involves more than half. That 50 percent threshold turns out to be a key dividing line for both the biomechanics of the shoulder and treatment decisions, as you will see below.

Tears also differ by location. An articular-sided tear affects the underside of the tendon, facing the joint. A bursal-sided tear affects the top surface, beneath the bursa that cushions the tendon from the bone above. Among athletes, articular-sided tears are more common in overhead sports like throwing, while bursal-sided tears are seen more often in athletes doing heavy resistance training.

Symptoms You Are Likely to Notice

The hallmark symptom is pain along the outside or front of your shoulder, often radiating partway down the upper arm. It tends to be worst during overhead movements like reaching into a cabinet, throwing a ball, or swimming, and it frequently flares at night when you roll onto the affected side. Many people describe a dull ache at rest that sharpens into a more intense, catching pain with specific movements.

Weakness is the other major complaint, though it can be subtle with smaller tears. You might notice difficulty lifting objects away from your body, trouble reaching behind your back, or a general sense that the shoulder gives out during certain tasks. Stiffness and a reduced arc of motion sometimes develop gradually, especially if you start guarding the shoulder to avoid pain.

Here is the tricky part: the severity of symptoms does not always match the size of the tear. A systematic review of imaging in people with no shoulder complaints found that partial-thickness tears and tendon changes show up on ultrasound in up to 47 percent of various study populations and on MRI in up to 100 percent of certain groups, depending on age and activity level.¹ In other words, plenty of people walk around with partial tears and feel nothing. This means that finding a tear on an MRI does not automatically explain your pain, and it is one reason why clinicians rely on the full clinical picture rather than imaging alone.

What Causes These Tears

The causes are usually a mix of factors rather than one single event. They fall into two broad categories. Intrinsic causes originate within the tendon itself: age-related degeneration, repetitive microtrauma, and a naturally limited blood supply in a region of the supraspinatus sometimes called the “critical zone.” That poor blood flow means the tendon has limited ability to repair itself once damage begins.²

Extrinsic causes come from outside the tendon. The most common is impingement, where the bony shelf above the shoulder (the acromion) or surrounding ligaments compress the cuff during arm elevation. Arthritic changes in the small joint at the top of the shoulder can contribute as well. In younger patients, shoulder instability can create secondary impingement as the ball of the joint shifts slightly during movement, pinching the cuff against surrounding structures.²

Athletes in overhead sports and people in physically demanding jobs are at higher risk. Among athletes, throwing sports are particularly associated with articular-sided tears, while strength-training athletes tend toward bursal-sided tears.³ But age is the single biggest risk factor overall, as tendon degeneration accumulates over decades.

How Partial-Thickness Tears Are Diagnosed

Your doctor will start with a physical exam. Several clinical tests can help identify which tendon is involved and how much function is compromised. For supraspinatus tears, the Jobe test (also called the “empty can” test, where you resist downward pressure with your arm extended and thumb pointed down) has good sensitivity, catching roughly nine out of ten tears, though its specificity is more modest. The “full can” test is less sensitive but better at ruling in a tear when positive.⁴ No single exam maneuver is definitive on its own, so clinicians typically combine several tests with your history and symptom pattern.

Imaging confirms the diagnosis. Both ultrasound and standard MRI perform similarly for detecting partial-thickness tears, and neither is clearly superior to the other. MR arthrography, where contrast dye is injected into the joint before scanning, is more sensitive and specific than either conventional MRI or ultrasound for picking up partial tears.⁵ That said, MR arthrography is more invasive and not always necessary. In practice, most people get a standard MRI or a diagnostic ultrasound first, with MR arthrography reserved for cases where the initial imaging is inconclusive but clinical suspicion remains high.

Why the 50 Percent Threshold Matters

That halfway mark in tendon thickness is not an arbitrary cutoff. Biomechanical research shows that once a bursal-sided tear exceeds about 50 percent of the tendon’s depth, the strain on the remaining intact portion increases rapidly and nonlinearly.⁶ The remaining fibers are now carrying a disproportionate load, which makes them vulnerable to further tearing. Articular-sided tears show a similar pattern: once they cross 50 percent and involve a key structural element called the rotator cable, they begin to change the way the ball of the shoulder moves in the socket during arm elevation.⁷

Interestingly, smaller articular-sided tears do not significantly alter shoulder mechanics at all in lab models.⁸ This helps explain why many low-grade tears are manageable without surgery: the shoulder can still function normally because the remaining tendon absorbs the load without being overstressed. It also explains why clinicians push harder for surgical consultation once a tear exceeds that 50 percent mark.

Non-Surgical Treatment Options

For tears involving less than half the tendon and for many patients regardless of tear size, conservative treatment is the first line. The goal is to reduce pain, restore range of motion, and strengthen the muscles around the shoulder so they compensate for the weakened tendon.

Physical Therapy and Shockwave Therapy

A structured rehab program is the backbone of non-surgical management. It typically starts with pain control and gentle range-of-motion work, then progresses to rotator cuff and scapular strengthening, and eventually incorporates sport-specific or functional exercises. The timeline varies, but most programs run at least three to six months before a decision about surgery is revisited.

Radial extracorporeal shockwave therapy has emerged as a supplement to standard rehab. In a randomized trial comparing shockwave therapy to a multimodal physical therapy program for degenerative partial supraspinatus tears, both groups improved significantly, but shockwave therapy produced larger and faster gains. Pain scores dropped from about 5 out of 10 down to 1 in the shockwave group, compared to about 1.7 in the physical therapy group.⁹ Shockwave is not a standalone fix, but it may accelerate recovery when combined with exercise.

Corticosteroid Injections

A steroid injection into the subacromial space can take the edge off pain quickly and is often used to create a window for physical therapy when pain is too severe to exercise. In a systematic review, corticosteroid injections provided stronger short- and medium-term pain relief compared to other injection types.¹⁰ A more recent randomized trial confirmed that corticosteroid injections outperformed platelet-rich plasma for short- and medium-term pain and patient-reported outcomes.¹¹

The catch is that steroid injections carry real risks for tendon health. A prospective study found that about 17 percent of patients developed a full-thickness tear within 12 weeks of a corticosteroid injection, and two-thirds of those conversions occurred in patients who already had a partial tear.¹² Corticosteroids weaken collagen and can accelerate tendon breakdown. Most clinicians limit the number of injections and use them as a bridge, not a long-term strategy.

Platelet-Rich Plasma Injections

PRP uses a concentrated sample of your own blood platelets, which are rich in growth factors, injected directly into the tear. The appeal is that PRP may promote healing rather than just masking symptoms. A meta-analysis of 12 studies involving over 750 patients found that PRP significantly reduced pain scores at six weeks, three months, six months, and even at one year compared to controls.¹³ However, functional scores only improved significantly in the short term; the long-term functional benefits did not reach statistical significance in that analysis.

For high-grade tears (those over 50 percent thickness), one study found that PRP injection into the tear site produced results comparable to surgical repair at a minimum two-year follow-up, with the average recovery period after PRP being about three months, substantially shorter than surgical recovery.¹⁴ That finding is provocative, though it comes from a single comparative study rather than a large randomized trial. In the systematic review, PRP provided better long-term pain relief than corticosteroids, even though corticosteroids won in the short term.¹⁰

When Surgery Becomes the Right Call

Surgery is generally considered when a tear involves more than 50 percent of the tendon’s thickness and has not responded to several months of conservative care, or when the tear is progressing on follow-up imaging. Active athletes and manual laborers with high-grade tears sometimes move to surgery sooner because the functional demands on their shoulders leave less margin for a weakened tendon.

There are two main arthroscopic approaches for high-grade partial tears. In tear completion and repair, the surgeon cuts through the remaining intact fibers to convert the partial tear into a full-thickness tear, then reattaches the entire tendon to the bone with suture anchors. In transtendinous (in situ) repair, the surgeon repairs the torn portion without disturbing the healthy fibers. Clinical studies comparing the two techniques show similar functional outcomes and pain relief for articular-sided tears.¹⁵ For bursal-sided tears, however, the retear rate may be higher with in situ repair.¹⁵ A biomechanical animal study confirmed that tear completion produced a stronger repair with better healing tissue than in situ repair for bursal-sided tears.¹⁶

A newer option involves a bioinductive collagen implant, a resorbable patch made from bovine collagen that is placed over the tear to stimulate the body’s own healing response. Registry data and a recent comparative study show that this implant produces improvements in pain and function comparable to traditional suture anchor repair for high-grade partial tears, with no difference in revision surgery rates.¹⁷ It can be used on its own or combined with a conventional repair.¹⁸

Will a Partial Tear Get Worse Over Time?

This is one of the most common questions people ask after a diagnosis, and the answer is more reassuring than you might expect. A systematic review pooling data across four studies found that partial tears progress to full-thickness tears at a rate of roughly 0.26 percent per month, which works out to about 3 percent per year.¹⁹ That rate was essentially the same for symptomatic and asymptomatic tears. In an MRI follow-up study, only about a quarter of partial tears increased in size over time, while the majority stayed the same or even shrank slightly.²⁰ By contrast, full-thickness tears enlarged in over 80 percent of cases in that same study, making the distinction between partial and full tears clinically meaningful for prognosis.

Two factors reliably predict progression. The first is how much of the tendon is already torn: when initial involvement exceeds roughly 47.5 percent of the thickness, the risk of significant progression jumps substantially. The second is a high physical work level.²¹ If you have a small tear and a desk job, the odds of it turning into a larger problem are low. If you have a near-50-percent tear and work on a construction site, the math is different.

Returning to Sports and Work After Treatment

Whether you go the conservative or surgical route, the criteria for getting back to full activity are broadly the same: full pain-free range of motion, shoulder strength at or near your pre-injury level, and the ability to perform sport-specific or job-specific tasks without symptoms.²² A systematic review of return-to-play criteria after rotator cuff surgery found that clinicians look at a mix of time since surgery, range of motion, strength, pain levels, functional recovery, and sometimes proprioception testing.²³

After surgical repair, you can expect at least four to six months before unrestricted activity, though many overhead athletes need closer to nine to twelve months. After conservative treatment, the timeline is shorter but highly individual. The key point is that returning too early, before strength has been fully restored, risks re-injury or progression of the tear.

The Role of Mental Health in Recovery

Something that rarely comes up in discussions of rotator cuff tears but consistently appears in the research is the influence of psychological factors on outcomes. A systematic review found that lower emotional and mental health at the time of diagnosis was associated with greater pain, more disability, and lower physical function.²⁴ Patient expectations also mattered: people who expected their treatment to help them generally reported better outcomes after surgery. This does not mean the tear is “all in your head.” It means that anxiety, depression, and catastrophizing about pain can amplify your experience of symptoms and slow your engagement with rehab. If your recovery feels stalled and you have been doing everything right physically, it may be worth addressing the psychological side as well.

Stem Cell Therapy and Other Experimental Approaches

Cell-based treatments, including stem cell and mesenchymal stromal cell injections, are generating interest but remain far from proven. A systematic review of cell therapy for tendon disorders found mixed results: four comparative studies on rotator cuff tears reported that cell therapy was more effective than control treatments and showed lower retear rates, but one study found no difference between groups.²⁵ A randomized controlled trial of stem cell injection for partial rotator cuff tears found that all groups, including the saline control, improved over time, with no significant differences between the stem cell group and controls for pain or function.²⁶ The saline group actually showed the largest pain reduction numerically, which is a humbling reminder of how powerful placebo effects can be in pain research.

If a clinic is offering you stem cell injections for a partial rotator cuff tear and charging a premium for it, the honest state of the science is that there is not yet convincing evidence that the cells themselves are driving the improvement. This may change as research matures, but at this point, PRP has a considerably stronger evidence base for partial tears than stem cells do.