Posterior Labral Tears and Posterior Instability

Posterior shoulder instability means the ball of the shoulder shifts backward in its socket. It accounts for roughly 5 to 10 percent of shoulder instability, and it behaves almost nothing like the anterior instability most people picture when they hear the word “dislocation.”

The condition covers a wide range, and the two ends of it look quite different.

Posterior dislocations do occur. They are usually the result of high-energy trauma - a motor vehicle accident is the classic mechanism - or of a seizure. These are significant injuries, and a complete radiographic series is required for the direction of the dislocation to be established.

Many posterior instability events, though, are not dislocations at all. In this group there is no single episode to point to, no emergency department visit, and no memory of the arm being put back in. What there is instead is pain - pain with pushing, pain with bench press, pain with push-ups, and a shoulder that feels unreliable in a way that is hard to describe. This group is larger in a clinic population, but it does not represent the whole condition.

A longer-term consideration applies across the whole range. Repeated backward loading does not only stress the labrum. It drives the humeral head against the posterior rim of the socket, and over years that contact can erode the posterior glenoid, increase the backward tilt of the socket, and produce an eccentric (uneven) pattern of arthritis - worn more on one side of the socket than the other - at an age when it would not otherwise be expected. This has implications for how the condition is managed early rather than late, and it is addressed in detail below.

Why the Diagnosis Can Be Difficult to Establish

The condition presents differently at each end of its range, and each presentation has features that make it difficult to identify.

A posterior dislocation may not be apparent on a single radiographic view. On a standard front-to-back projection the humeral head lies behind the glenoid rather than beside it, so the two structures overlap and the appearance can be close to normal. The axillary view resolves this. Taken from below with the arm abducted, it looks along the plane of the joint and demonstrates the position of the humeral head directly. The axillary view is a standard part of the radiographic series I obtain in the office, and it is the reason a complete series matters at the initial assessment.

The direction of a seizure-related dislocation should be confirmed rather than assumed. The association between seizures and posterior dislocation is well recognized, but anterior dislocation also occurs during seizures. The mechanism narrows the possibilities; the imaging establishes the diagnosis.

Where there has been no dislocation, there is no discrete event to anchor the assessment. The presentation is activity-related pain in a young, active patient, a description consistent with a wide range of shoulder conditions.

The presenting symptom is pain rather than a sense of instability. Patients seldom describe the shoulder as coming out backward. They describe pain with pressing; pain when the arm travels across the body, including lying on that side at night; and pain through the follow-through of a golf swing, a bat swing, or a racquet stroke. Many describe it as a loss of capacity rather than as pain at all - that they have stopped bench pressing because the arm feels weak, or because it no longer tolerates the load. The vocabulary of instability does not enter the history, which is one reason the diagnosis is not the first consideration.

The MRI findings are subtle. A posterior labral tear is less conspicuous than an anterior one, and the associated features - increased glenoid retroversion, a thickened posterior labrum, a capacious (stretched and roomy) posterior capsule - are identified most reliably when they are specifically sought.

In the non-traumatic group, symptoms are frequently present for months to years before assessment, and the loading that produced them usually continues throughout that period.

The Anatomy: What Holds the Shoulder Back

The socket of the shoulder - the glenoid - is shallow and slightly tilted. Its orientation relative to the shoulder blade is called version. A socket that faces slightly backward is retroverted, and a small amount of retroversion is entirely normal.

Stability at the back of the joint comes from three things:

The posterior labrum, a rim of cartilage that deepens the socket and acts as a bumper against backward translation.

The posterior capsule and ligaments, which tighten to restrain the head as the arm moves forward and across the body.

Dynamic muscular control - the rotator cuff and, importantly, the muscles that position the shoulder blade. A shoulder blade that does not stay properly oriented changes where the socket is pointing when force arrives, which is why scapular mechanics are assessed as part of this diagnosis rather than separately from it.

Two structural variations make the back of the shoulder more vulnerable, and both are present from the start rather than acquired:

• Increased glenoid retroversion. The more the socket faces backward, the less bone stands behind the humeral head to contain it
• Glenoid dysplasia - a developmental underdevelopment of the posteroinferior part of the socket. It is strongly associated with posterior labral tears, and it means some people arrive at the gym already predisposed

Three Ways Posterior Instability Develops

1. A Single Traumatic Event

A posterior dislocation is usually a high-energy injury. The mechanisms that produce one are:

• Motor vehicle accidents - the classic pattern, with force driven up the arm from the steering wheel or dashboard while the shoulder is forward and rotated inward. This is the most common traumatic cause
• A seizure, where the powerful internal rotators overwhelm the external rotators and drive the head backward. The association is well known, but it should not be assumed - patients also dislocate anteriorly during seizures, and the direction has to be confirmed on imaging rather than inferred from the history
• Electrical injury, through the same mechanism of overwhelming muscular contraction
• A direct blow to the front of the shoulder, or a fall onto an outstretched arm with the shoulder forward and rotated inward

A traumatic posterior dislocation can produce a reverse Bankart lesion - the posterior labrum torn off the back rim of the socket - and a reverse Hill-Sachs lesion, an impaction dent in the front of the humeral head where it was driven against the rim.

These injuries can also produce a fracture of the posterior glenoid rim or of the humeral head itself, which is one of several reasons a complete imaging series is needed. An axillary view is essential, and a CT scan can sometimes be ordered to assess the extent of any bony injury.

2. Repetitive Loading - The Common Route

This is the group most patients on this page belong to. No single injury, but thousands of repetitions of a movement that pushes the humeral head backward.

Four populations account for most of this group.

• Athletes who block or push. Offensive linemen and linebackers load the shoulder in this direction on every play, as do rugby forwards, wrestlers, and gymnasts
• People who strength train with free weights, and powerlifters, particularly those who bench press regularly or with very heavy weight
• Athletes in rotational sports - golf, baseball, tennis - where the follow-through carries the arm across the body at speed
• Yoga practitioners and anyone doing high-volume body-weight work. High planks, push-up positions, downward-facing dog, and vinyasa transitions all load the arm forward and through the hand. This is a group that could be overlooked, since no external weight is involved - but body weight through a forward-flexed arm produces the same direction of load, and the volume of repetitions can be high

Over time, repetitive backward loading fatigues the posterior labrum and stretches the posterior capsule. The labrum can fray, tear, or peel away from the rim while still attached to the thin sleeve of tissue covering the bone, and the posterior capsule can gradually stretch and become slack. These changes accumulate over months to years rather than arising from a single episode, which is why most patients in this group cannot identify when the problem began.

3. Structural Predisposition

Some shoulders are set up for this - increased retroversion, glenoid dysplasia, or generalized ligamentous laxity. In these patients, symptoms may begin with much less provocation, and the underlying shape of the socket is part of the picture that treatment has to account for. Where laxity is generalized and multidirectional, the condition shades into multidirectional instability, which is managed differently again.

Why Pressing Movements Provoke It

The bench press is the most common provocative exercise in this diagnosis, and the mechanics explain why it - and several body-weight positions - behave the same way.

When lying on a bench, the shoulder blade is fixed between the torso and the bench and cannot move. In other pressing positions - standing, seated at a machine, or in a push-up - the shoulder blade retains some freedom to rotate and glide, and that movement distributes load. The bench removes it.

The position that matters is the arm held forward and close to the midline under load. Force is transmitted down the long axis of the arm, and when the arm is flexed forward in front of the body - particularly with the hands close together and a heavy weight - that force drives the humeral head backward into the socket. The wider the arms are set, the less of that translation occurs, which is why grip width changes the demand on the posterior labrum more than most people expect.

With the shoulder blade fixed against the bench, the posterior glenoid absorbs that force directly rather than accommodating it.

The same position occurs without any weight at all. A high plank, the top of a push-up, downward-facing dog, and the transitions of a vinyasa flow all place the arm forward and loaded through the hand, with body weight driving the humeral head backward. Yoga practitioners are a group at risk for this reason, and one that could be overlooked - the loading is repetitive, sustained, and performed in exactly the provocative position.

Repeated across a high volume of repetitions over years of training, the posterior labrum is required to restrain the same translation many thousands of times. The resulting failure is one of fatigue rather than of a single injury.

Modifying Training and Exercise Selection

In general I caution against bench press and push-ups in patients with posterior instability, recognizing that some patients will continue them. There are alternatives that train the same muscle groups - the pectorals, triceps, and deltoids - without producing the same shear across the joint, and most patients find the substitution costs them little.

The principle behind all of it: avoid positions where the arm is near the midline of the body, crossing the body, or overhead while pushing. Those are the positions that concentrate force on the posterior labrum and the cartilage behind it.

The exercises I caution against most specifically are dumbbell bench press, dumbbell fly, incline bench press, and military press. All of these place the arms near the midline or overhead under load, and all of them increase force across the posterior labrum and the cartilage in that region. Incline pressing needs separate mention, because patients often switch to it believing it is easier on the shoulder - moving the bench toward upright moves the arms toward overhead, which works against them. In my experience these are highly irritating maneuvers - not only for posterior instability, but for biceps and SLAP irritation as well, which frequently coexists in the same shoulder and the same lifter.

For yoga and body-weight practice, the approach is modification rather than substitution. High planks, downward-facing dog, and the transitions of a vinyasa flow place the arm in the same forward-loaded position, but they are part of a practice rather than isolated exercises, and swapping them out is neither practical nor necessary. Speak to your instructor about modifications - most can suggest an adjustment to a pose, or a different way through a transition, that reduces the load on the shoulder. Where a movement is uncomfortable, modify it rather than working through it.

On why the machine versions are acceptable where the free-weight versions are not: the determining factor is the path of the arm rather than the resistance. A dumbbell permits the arm to travel into the deep, cross-body position behind the plane of the body, where posterior translation is greatest. A machine constrains the arm to a fixed arc and removes that end range. The muscle is loaded as before; the joint is not required to stabilize in the position it stabilizes least well.

Symptoms

Pain is the usual complaint, and instability is usually not.

• Pain at the back of the shoulder, though many patients report it more vaguely as deep or hard to localize
• Pain with pushing - bench press, push-ups, blocking, pushing a heavy door
• Pain reaching forward and across the body, or when carrying something in front
• Pain lying on that shoulder at night, which brings the arm across the body under body weight
• Pain through the follow-through of a golf swing, a bat swing, or a racquet stroke - the phase in which the arm crosses the body at speed
• A sense of the shoulder shifting or clunking, often only in specific positions
• Perceived weakness under load - commonly described as having given up bench press because the arm feels unreliable rather than because it is painful
• Loss of confidence in the arm under load, rather than a fear of the shoulder coming out
• Symptoms with the arm forward and rotated inward - the position that combines the two directions of stress

Some patients can shift the shoulder backward on purpose and will demonstrate it in the office. The useful question is not whether the shoulder can be moved deliberately, but whether it also shifts on its own during ordinary activity, and whether it hurts when it does. A shoulder that can be shifted at will and painlessly is a different situation from one that gives way unexpectedly under load, and the two are assessed differently.

How the Diagnosis Is Made

The history is often directive. Which movements produce the pain, whether pressing capacity has changed over the preceding year, and what has happened to training volume are the questions that most reliably narrow the differential.

The examination includes specific posterior stress testing - the jerk test and the Kim test - which load the shoulder in the position of vulnerability and reproduce the symptom. The assessment also covers the labrum and biceps, the rotator cuff, and scapular mechanics, because a shoulder blade that does not control its position changes where force lands and is frequently part of the problem.

Radiographs, including an axillary view. As described above, a posteriorly dislocated humeral head overlaps the glenoid on a standard front-to-back projection and the appearance can be close to normal. The axillary view looks along the plane of the joint and demonstrates the position of the humeral head directly. It is a routine part of the series I obtain rather than an additional study ordered when a specific concern arises.

MRI defines the posterior labral tear and the capsule. It also shows the associated findings that point toward a predisposed shoulder - a thickened or enlarged posterior labrum, an unusually roomy posterior capsule, and posteroinferior deficiency of the socket. As with other labral pathology, a standard MRI without contrast is usually sufficient in my practice, particularly on a 3 Tesla scanner. MR arthrography, where contrast is injected into the joint first, is reserved for cases where the standard study has not answered the question and clinical suspicion remains high.

CT is not obtained routinely, but can be considered where there is suspicion of bone loss, or where the degree of retroversion or the shape of the socket needs to be measured more accurately than MRI allows. The morphology of the glenoid is central rather than incidental when it comes to planning - it influences whether a soft-tissue repair alone is likely to be sufficient, and it bears directly on the arthritis considerations below.

Conditions That Frequently Coexist

Posterior labral pathology rarely sits in isolation, and more than one of the following is often present in the same shoulder.

• Superior labral (SLAP) tears and biceps pathology - the superior labrum and the biceps anchor sit adjacent to the posterior labrum, and the loaded, arm-forward positions that provoke posterior symptoms also load the biceps anchor. Pain at the front of the shoulder alongside posterior symptoms usually means both are involved, and the exercises that irritate one tend to irritate the other
• Scapular dyskinesis - abnormal shoulder blade mechanics change where the socket is pointing at the moment force arrives. This is commonly part of the picture rather than a separate diagnosis, and scapular retraining forms part of the treatment in most of these patients
• Glenohumeral osteoarthritis - the endpoint of the wear process described in the next section, and occasionally already present in a mild form by the time a posterior labral tear is identified in an older patient
• Multidirectional instability - where the laxity is not confined to one direction. The treatment differs substantially, which is why the two are separated early
• Anterior instability - a shoulder can be unstable in more than one direction, and bidirectional instability is recognized

Posterior Loading and Early Arthritis

This aspect of the condition receives comparatively little attention and has substantial long-term significance.

A shoulder in which the humeral head sits backward in the socket loads the back of that socket disproportionately. Cartilage wears where load concentrates. As the posterior cartilage and then the underlying bone erode, the socket tilts further backward, which lets the head sit further back still, which concentrates the load further. The process is self-reinforcing, and it progresses slowly enough that patients often experience it simply as a shoulder that has been intermittently sore for years.

A Recognized Four-Stage Sequence

The glenoid is classified by its wear pattern, and the sequence produced by this process has been described in four stages. The staging clarifies where a given shoulder sits along it.

Stage 1 - the B0 glenoid, also described as pre-osteoarthritic posterior subluxation of the humeral head - is the stage of greatest practical interest. It describes a shoulder in which the humeral head has taken up a backward position while the cartilage and bone remain intact: a shoulder at risk, identified before structural damage has occurred.

Shoulder arthritis is usually recognized only once cartilage has been lost. The value of the B0 concept is that it identifies the shoulder on that trajectory while the articular surface is still preserved, at a point where subsequent loading can still influence the course.

Distinguishing Two Pathways

The B0 pathway and posterior instability arising from repetitive loading are not established as the same condition, and the distinction should be stated precisely.

In the work that defined it, pre-osteoarthritic posterior subluxation was described in young men with no history of injury, no prior dislocation, and no generalized ligamentous laxity. The one risk factor identified was increased retroversion of the socket - averaging around 15 degrees in the symptomatic shoulder against 10 degrees on the other side, where 2 to 8 degrees is normal. On that account the head sits backward because of the shape the shoulder was built with, rather than because a labrum tore.

Posterior instability, by contrast, is a failure of the structures that hold the shoulder - the labrum and capsule - whether from a single injury or from years of repetitive loading.

The two are distinguishable in principle and frequently difficult to separate clinically. The presentations overlap closely: pain, gradual functional decline, sometimes a sense of catching, and often a subjective feeling of instability alongside normal apprehension testing. Patients in the original B0 series reported precisely this pattern, and the literature notes that the condition closely resembles instability in young patients, which contributed to its late recognition as a distinct entity.

What the two share is the end state: a humeral head that habitually loads the posterior glenoid. Whether the origin lies in the morphology of the socket, in failure of the labrum, or in a combination of the two, the posterior glenoid bears the load. The cause of that loading remains debated; its consequence does not.

A useful comparison is the meniscus in the knee. A traumatic meniscal tear and a degenerative meniscal tear are both correctly described as meniscal tears, and both appear on an MRI report under the same heading. They are not the same clinical problem. One is a discrete injury to healthy tissue in a knee that was previously normal. The other is a feature of a joint that has been changing gradually for years, and the tear is part of that broader process rather than a separate event.

Posterior labral injury divides along the same line. A traumatic posterior labral tear is a structural injury to a shoulder that was sound before it. A degenerative posterior labral injury, arising within the spectrum described above, is one finding in a joint already undergoing eccentric (uneven) change. The distinction matters most when deciding whether and when to operate, which is addressed below.

Implications for Younger Patients

Eccentric posterior wear is among the more demanding patterns to address if the shoulder eventually requires replacement, because the version of the socket has to be corrected in addition to resurfacing it. Reaching that point in the fifth decade rather than the eighth carries substantially different consequences.

The certainty here should not be overstated. The staging describes a recognized sequence, but the natural history in any individual patient is not predictable, the timeline is long, and the underlying cause remains debated - including whether increased retroversion drives the subluxation or follows from it.

What is not in dispute is that repetitive backward loading concentrates force on the posterior glenoid, and that this loading is modifiable. For this reason the exercise guidance above forms a substantial part of the treatment rather than an adjunct to it. In a young patient with a posteriorly loaded shoulder, training decisions taken over the following years carry more weight than any intervention available once the wear is established.

Non-Surgical Treatment

Most posterior instability is managed without surgery, and a well-constructed program is effective for a substantial proportion of patients.

Activity modification is the first measure, and in this diagnosis it is the single most effective one - see the exercise substitutions above. Reducing the provocative loading is what allows the remainder of the program to take effect.

Physical therapy targets the posterior rotator cuff, the deltoid, and the scapular stabilizers. Scapular control carries particular importance in this diagnosis, because the orientation of the glenoid at the moment of loading depends on the position of the shoulder blade. The Scapular Mechanics Program sets out that work in detail and can be used alongside a therapy program. Posterior capsular stretching is generally not part of the program - the posterior capsule in these shoulders is usually too loose rather than too tight, which is the opposite of the situation in most other shoulder conditions.

For structured home exercise alongside a therapy program, the AAOS shoulder conditioning program is a reasonable general resource.

Allow adequate time. Posterior instability responds slowly, and a program undertaken over a few weeks while provocative loading continues does not constitute an adequate trial. A dedicated three-month program, with the provocative loading removed, is a reasonable test.

Injections have a limited role and are used more for diagnostic clarification than treatment.

Surgery

Arthroscopic posterior labral repair is the operation I perform for this condition.

Through small incisions at the back of the shoulder, the torn posterior labrum is reattached to the rim of the glenoid with suture anchors, restoring the bumper that resists backward translation. Where the posterior capsule has stretched and become slack, it is tightened at the same time - capsular plication - because a repaired labrum inside a capsule that remains loose has not fully addressed the problem.

Results are generally good in appropriately selected patients, with high rates of return to sport and to lifting. Selection is central to that result. Outcomes are less predictable in patients with significant glenoid retroversion or posterior bone loss, where the morphology of the socket contributes as much to the instability as the torn tissue does.

How the Two Pathways Affect the Threshold for Surgery

The distinction drawn earlier - between a traumatic posterior labral tear and a degenerative one arising within a spectrum of posterior wear - has direct surgical implications, and they run in opposite directions.

In a traumatic posterior labral tear with demonstrable instability, there is an argument for treating more definitively rather than waiting. The reasoning is not only symptomatic. An unstable shoulder generates repeated shear across the posterior glenoid with every loaded movement, and that acquired shear is itself one of the mechanical contributors to the degenerative process described above. Restoring stability addresses the presenting symptom and removes a driver of later wear. In a young patient with a structurally sound joint and a discrete injury, that is a favorable set of conditions for repair.

In a degenerative posterior labral injury within an established pattern of posterior wear, greater caution is warranted. Here the labral finding is one feature of a joint that has been changing for years rather than an isolated lesion, and repairing it does not address the process producing the symptoms. The comparison to the knee holds: arthroscopic treatment of a degenerative meniscal tear in an arthritic knee is well recognized as unreliable, for the same reason. Non-surgical management, activity modification, and attention to the loading pattern carry more weight in this group.

Separating the two rests on the whole picture rather than the MRI report - whether there was a discrete injury, the age of the patient, the condition of the cartilage, and the morphology and version of the glenoid on CT. A posterior labral tear reported on a scan does not, by itself, indicate which of the two situations is present.

For that smaller group, bony procedures exist - posterior bone grafting to rebuild the deficient rim, or an osteotomy to correct excessive retroversion. These are uncommon operations for an uncommon situation, and the decision to consider one rests on the CT measurements.

Return to the preoperative loading pattern warrants careful consideration. A repair restores the anatomy but does not alter the mechanics that fatigued the labrum, and the exercise substitutions above remain as relevant after surgery as before it.

Recovery After Posterior Labral Repair

The sling position differs from that used after an anterior repair. Following an anterior repair the arm is supported across the body. Following a posterior repair that position places tension on the repair, so the arm is instead supported slightly abducted and externally rotated. The arrangement is deliberate rather than incidental.

Frequently Asked Questions

Can I have posterior shoulder instability without ever having dislocated my shoulder?

Yes, and it is common. Many posterior instability problems develop from repeated backward loading of the shoulder - from bench press, push-ups, or blocking in contact sport - which fatigues the posterior labrum and stretches the capsule gradually rather than tearing it in one event. True posterior dislocations do occur as well, usually from high-energy trauma such as a car accident, or during a seizure.

Why does bench press hurt my shoulder?

Because of where the arms are. Force travels down the long axis of the arm, and when the arm is held forward in front of the body with the hands close to the midline under a heavy weight, that force drives the ball of the shoulder backward into the socket. Lying on a bench also pins the shoulder blade so it cannot move and accommodate the load. Setting the hands wider reduces the effect considerably. Repeated over years, this loads the posterior labrum in the direction it is least able to resist.

Do I have to stop lifting?

Not lifting altogether. I generally advise against bench press - flat and incline - as well as push-ups, dumbbell fly, and military press, because these place the arms near the midline or overhead under load. Incline pressing needs specific mention, since people often switch to it assuming it is gentler on the shoulder, when moving the bench toward upright brings the arms closer to overhead. There are good alternatives for the same muscles - a chest press machine with the hands set wide, the fly machine, and lateral and front dumbbell raises - which train the pectorals, triceps, and deltoids without producing the same shear across the joint.

Why is a fly machine acceptable when dumbbell flys are not?

Because the problem is the path of the arm rather than the resistance. A dumbbell lets the arm drift into the deep, cross-body position where the shoulder is driven backward hardest. A machine holds the arm on a fixed arc and removes that end range. The muscle still gets the work.

Can a backward-sitting shoulder lead to arthritis?

It can, and this is why the condition deserves attention even when the pain is manageable. When the ball of the shoulder habitually sits backward in the socket, wear concentrates on the back of the socket. Over years this can erode the posterior glenoid, tilt the socket further backward, and produce an eccentric - that is, uneven - pattern of arthritis in a relatively young person. Surgeons describe this in four stages, beginning with the B0 glenoid - a shoulder in which the head already sits backward but the cartilage is still normal - and ending in established glenohumeral arthritis. Not everyone progresses through them, and the timeline is long, but the sequence is recognized and the loading that drives it can often be changed.

What is a B0 glenoid?

It is the earliest stage of this process: the ball of the shoulder sits permanently backward in the socket, but the cartilage and bone are still intact. It is sometimes described as pre-osteoarthritic posterior subluxation, and the reason it has a name is that it identifies a shoulder at risk before any damage has occurred - which is unusual, since arthritis is normally recognized only once cartilage has already been lost.

Is a torn posterior labrum always treated the same way?

No, and the difference matters. A traumatic posterior labral tear in an otherwise healthy shoulder is a discrete injury, and where it is producing instability there is an argument for repairing it rather than waiting - partly to relieve symptoms, and partly because an unstable shoulder generates repeated shear across the back of the socket that contributes to later wear. A degenerative posterior labral injury, occurring in a joint that has been changing gradually for years, is treated more cautiously, because the tear is one feature of a broader process rather than the whole problem. The comparison is to the knee, where a traumatic meniscal tear and a degenerative meniscal tear share a name but not a treatment.

Is a posterior labral tear the same thing as a B0 glenoid?

Not necessarily, and the distinction matters. A posterior labral tear is a failure of the tissue that holds the shoulder, usually from injury or repetitive loading. A B0 glenoid was originally described in young men with no injury at all, where the socket itself was tilted backward more than usual. The two overlap in how they present and can be genuinely difficult to separate in the office, and both end with the back of the socket taking more load than it was built for - but they are not established as the same condition.

How is posterior instability diagnosed?

Through the history - particularly what movements provoke the pain - combined with specific examination tests that load the shoulder backward, such as the jerk and Kim tests. MRI shows the posterior labral tear and the capsule, and a standard study without contrast is usually sufficient. A CT scan is not routine, but may be considered where bone loss is suspected or where the shape and version of the socket need measuring more precisely, since those influence whether a soft-tissue repair alone is likely to hold.

Why do I need an axillary X-ray view?

Because a posterior dislocation can look close to normal on a standard front-to-back film. In that view the ball sits behind the socket rather than beside it, so the two overlap and the shoulder can appear located. The axillary view is taken from below with the arm out to the side and looks along the plane of the joint, which shows the position of the ball directly. It is part of the routine series for that reason.

I had a seizure and dislocated my shoulder. Does that mean it went out the back?

Not necessarily. The association between seizures and posterior dislocation is well known, but people also dislocate anteriorly during seizures. The direction has to be established from imaging rather than assumed from the mechanism, and that is another reason a complete X-ray series matters.

Is a posterior labral tear the same as a SLAP tear?

No, though they are closely related. Both are tears of the labrum, the cartilage rim around the socket, but in different places. A SLAP tear involves the labrum at the top of the socket, where the biceps tendon anchors. A posterior labral tear involves the back of the rim. They frequently occur together, because the arm-forward loaded positions that stress the posterior labrum also stress the biceps anchor, and pain at the front of the shoulder alongside posterior symptoms usually means both are involved.

What is a reverse Bankart lesion?

It is a tear of the labrum off the back rim of the socket - the mirror image of the Bankart lesion seen in anterior instability. It is the lesion produced by a traumatic posterior dislocation, though repetitive loading can produce a similar tear gradually.

Why is my sling holding my arm out to the side after surgery?

Because the position that stresses a posterior repair is the arm across the body - the opposite of an anterior repair. Holding the arm slightly out and rotated outward keeps tension off the repaired tissue while it heals.

How long before I can bench press again after surgery?

Pressing movements are generally reintroduced from around four to six months, and usually in a modified form. A repair restores the torn tissue, but it does not change the mechanics that fatigued it, so returning to the identical program that caused the problem is not the goal.

Shoulder pain with pushing or pressing that will not settle?

Dr. Gabriella Ode is a fellowship-trained sports medicine and shoulder surgeon at the HSS Sports Medicine Institute, head team orthopaedic surgeon for the New York Liberty, and assistant team orthopaedic surgeon for the Brooklyn Nets. She treats shoulder instability in athletes and lifters at every level. Request an appointment or request a remote second opinion.

Financial disclosure.

Dr. Ode is a paid consultant for Advita Ortho and ConMed, manufacturers of orthopaedic implants and surgical instrumentation. These relationships are reported publicly through the CMS Open Payments database. She receives no compensation for this website, and no compensation is tied to any individual patient’s treatment decision. Her complete financial disclosures are available here.

This article is for general education and is not a substitute for individual medical advice. Please consult a physician about your specific condition.

Written by Gabriella E. Ode, MD, FAAOS, FAOA

Sports Medicine and Shoulder Surgeon, HSS Sports Medicine Institute
Associate Professor of Orthopaedic Surgery, Weill Cornell Medical College
Head Team Physician, New York Liberty

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