What Is a Hill-Sachs Deformity and How Is It Treated?

A Hill-Sachs deformity is a dent in the back of the ball of your shoulder joint, created when the ball slams into the edge of the socket during a dislocation. It is a compression fracture of the humeral head, and it shows up on imaging in a surprisingly large proportion of people who have dislocated their shoulder even once. Whether that dent causes ongoing problems depends on its size, its position, and how it interacts with the rest of the shoulder’s anatomy during movement.

How the Dent Forms

Your shoulder is built for mobility over stability. The ball of the upper arm bone (the humeral head) is much larger than the shallow socket (the glenoid) it sits in, which is part of what gives you such a wide range of motion. When the shoulder dislocates anteriorly, meaning the ball slides forward and out of the socket, the back of the humeral head crashes into the hard, bony front rim of the glenoid. That collision crushes the softer bone on the humeral head, leaving a characteristic impression fracture on its posterior surface.¹ The size of the resulting dent depends on how forceful the dislocation was, the angle of the arm at the time, and whether the shoulder came out of joint once or many times.

Biomechanical research has shown that the direction of dislocation matters. When the ball dislocates straight forward rather than at an angle, the greater tuberosity (a bony landmark near the top of the humerus) engages with the glenoid rim about 40% more often.² That engagement is what carves the defect. A purely anterior dislocation tends to produce a more prominent lesion than one that angles downward.

How Common Is It

If you have dislocated your shoulder, the odds that you already have a Hill-Sachs defect are high. A systematic review pooling data from multiple studies found that roughly seven out of ten first-time anterior dislocations come with a Hill-Sachs lesion on imaging. Among people who have dislocated more than once, the figure rises to about 85%.³ Each subsequent dislocation tends to deepen or widen the existing dent, or create new damage, which is one reason surgeons take recurrent dislocations seriously. A separate study comparing first-time and recurrent dislocators confirmed that the prevalence of Hill-Sachs lesions was significantly higher in the recurrent group.⁴

Many people with a small Hill-Sachs lesion after their first dislocation will never know they have one unless they get an MRI. The dent sits on the back of the humeral head, away from the main weight-bearing surface, and a small one may never cause symptoms beyond the initial dislocation itself. The lesion becomes clinically important when it is large enough, or positioned just right, to catch on the glenoid rim during arm movement.

The Bankart Lesion Connection

A Hill-Sachs defect rarely travels alone. When the humeral head crashes forward during a dislocation, the soft cartilage lip (labrum) and ligaments on the front of the glenoid often tear too, producing what is called a Bankart lesion. In some cases, a chunk of bone from the glenoid rim breaks off with the labrum (a bony Bankart). These two injuries feed off each other in a way that makes instability worse over time.

Radiological data shows that the co-occurrence of Hill-Sachs and Bankart injuries is very high, with one study reporting an odds ratio over 11 for having both together.⁵ Larger Hill-Sachs dents are also associated with a greater likelihood of a Bankart lesion being present.⁶ This pairing matters for treatment planning because addressing the Hill-Sachs defect without fixing the Bankart tear, or vice versa, can leave the shoulder unstable.

On-Track Versus Off-Track

Not every Hill-Sachs lesion is a problem, and the concept that separates the benign ones from the dangerous ones is the “glenoid track.” As you raise and rotate your arm, the glenoid traces a predictable path across the back of the humeral head. Researchers measured this contact zone and found that it extends about 84% of the glenoid’s width from a medial reference point on the humeral head.⁷ If your Hill-Sachs dent falls within that track, the glenoid simply glides over it during normal movement and the defect cannot catch on anything. This is called an “on-track” lesion, and it generally does not contribute to further instability.⁸

If the dent extends beyond the medial edge of the glenoid track, however, it becomes “off-track.” In that position, the rim of the defect can catch on the edge of the glenoid when you externally rotate or abduct your arm, and that engagement can lever the shoulder right back out of joint. The glenoid track concept is now one of the most widely used frameworks for deciding how aggressively a Hill-Sachs lesion needs to be treated.⁹ Two key measurements, the glenoid track width and the Hill-Sachs interval, are compared: if the track width is greater than the interval, the lesion is on-track and relatively safe. If the interval exceeds the track width, the lesion is off-track and carries a real risk of engagement and redislocation.¹⁰

The on-track/off-track distinction also explains why two people with seemingly similar-sized dents can have completely different experiences. A moderate Hill-Sachs lesion in a shoulder with no glenoid bone loss might be on-track and cause no engagement. The same lesion in a shoulder that has also lost bone from the front of the glenoid (shrinking the effective track width) might be off-track and highly unstable. Both the humeral and glenoid sides of the equation matter.

Diagnosis and Imaging

A Hill-Sachs lesion can sometimes be suspected on a standard X-ray taken with the arm internally rotated, but X-rays miss smaller defects. MRI is commonly ordered because it also shows soft-tissue damage like labral tears, cartilage injury, and rotator cuff problems. For measuring the defect precisely enough to calculate the glenoid track, CT scans are more reliable. A systematic review found that three-dimensional CT reconstruction had the highest consistency among observers for quantifying Hill-Sachs lesion dimensions, outperforming both standard two-dimensional CT and MRI.¹¹ Dedicated research on 3D CT confirms that it is effective and reproducible for determining lesion size and for applying the glenoid track concept, though measurements may slightly underestimate true defect size.¹²

Where the lesion sits on the humeral head also influences whether it will engage. One study measured the angle of the lesion relative to the biceps tendon groove and found that patients whose lesions engaged on physical examination had a significantly more medially oriented defect, with a biceps angle averaging about 152° compared to 142° in non-engaging cases.¹³ There is also a significant association between engagement on clinical examination and the degree of glenoid bone loss, reinforcing the point that both sides of the joint need to be evaluated together.¹⁴

When Surgery Is Not Needed

Small, on-track Hill-Sachs lesions that do not engage during arm movement are often managed without surgery, especially if the associated Bankart lesion has been addressed or is minor. Rehabilitation focuses on strengthening the rotator cuff, the deltoid, and the muscles that stabilize the shoulder blade.¹⁵ The goal is to build a muscular envelope around the shoulder that compensates for the bony defect and keeps the humeral head centered in the socket during dynamic movement. Physical therapy alone works best for people who are not placing heavy rotational demands on the shoulder, meaning the casual weekend athlete who dislocated once and has a small dent may do fine with a structured rehab program.

The problem arises when lifestyle or sport demands push the shoulder into the exact positions where engagement can occur: arm overhead, externally rotated, and loaded. Contact sports, overhead throwing, and racket sports are the obvious triggers. For these patients, even a technically on-track lesion may become a nuisance if the shoulder lacks the dynamic stability to resist the forces involved.

Remplissage and Bankart Repair

The most common surgical approach for a Hill-Sachs lesion is to pair a Bankart repair (reattaching the torn labrum) with a procedure called remplissage. In a remplissage, the surgeon fills the Hill-Sachs defect by anchoring the infraspinatus tendon and the posterior capsule into the dent, effectively converting an intra-articular void into an extra-articular one. The tissue plug prevents the glenoid rim from catching in the defect.

Adding a remplissage to a standard Bankart repair lowers the rate of recurrent instability without meaningfully sacrificing shoulder range of motion.¹⁶ A randomized controlled trial found significantly greater risk of recurrent instability in patients who had a Bankart repair alone compared to those who also received a remplissage, and the benefit was particularly pronounced in patients with larger Hill-Sachs lesions (20 mm or more in width, or 15% or more of the humeral head).¹⁷ A prospective study comparing the two groups found no significant difference in range of motion, with external rotation differing by only about 3-5 degrees between the groups.¹⁸

Lab testing on cadaveric shoulders confirms that remplissage effectively prevents engagement even in moderate to large defects. However, it does stiffen the shoulder slightly compared to the intact state and can reduce internal-external rotation in certain arm positions.¹⁹ In practice, this small reduction in motion does not seem to bother most patients, though it may matter for athletes in sports requiring extreme ranges of external rotation, like baseball pitching or competitive swimming.

Options for Large Defects

When the Hill-Sachs dent is very large, a remplissage may not be enough. Several reconstruction options exist for these cases. One approach is osteochondral allograft transplantation, where a size-matched plug of bone and cartilage from a donor humeral head is press-fit into the defect to restore the ball’s natural contour. This can be done arthroscopically, with the allograft seated flush to the articular surface without internal hardware.²⁰ Case reports have shown complete graft incorporation and stable, functional shoulders at follow-up beyond two years.²¹

For the most severe scenarios, where both a large engaging Hill-Sachs lesion and critical glenoid bone loss are present, some surgeons combine partial humeral head resurfacing with glenoid bone grafting and an open Bankart repair. This triple approach addresses both sides of the joint.²² Another option, the Latarjet procedure, transfers a piece of bone from the coracoid process to the front of the glenoid to widen the socket. In patients with glenoid bone loss greater than 25% and off-track Hill-Sachs lesions treated with a Latarjet without remplissage, 93% returned to sports and 86% returned to their pre-injury level.²³

An older technique, the Weber osteotomy, rotates the humeral head to move the defect out of the engagement zone. However, the amount of rotation achieved is unpredictable, and over-rotation has been linked to arthritis and loss of internal rotation, making it a less favored choice today.²⁴

Hill-Sachs Lesions in Younger Patients

Adolescents and teenagers present a particular challenge. They have years of growth and activity ahead of them, and their recurrence rates after a first dislocation are among the highest of any age group. Research has identified Hill-Sachs lesions as a risk factor for recurrent instability requiring revision surgery in this population, especially in patients under 16 and those who have already experienced more than one dislocation before surgery.²⁵ Studies in adolescents also show that larger Hill-Sachs lesion volumes measured on MRI correlate with more episodes of instability, suggesting that the size of the defect should influence how early and how aggressively it is addressed.²⁶

Adding a remplissage to the Bankart repair appears to be particularly useful in this group. One study of adolescent athletes found that those who received the combined procedure had lower recurrence rates and better patient-reported outcomes than those who had a Bankart repair alone.²⁷ Whether the benefit comes specifically from filling the defect or from the additional tightening effect on the posterior capsule is still debated, but the clinical result is encouraging for a population that historically struggles with high revision rates.

Long-Term Outlook and Arthritis Risk

A common concern after any surgical procedure involving articular bone is whether it accelerates joint wear. In long-term follow-up of patients who underwent Bankart repair with remplissage, about 17% showed radiographic signs of arthritis, though the vast majority of those were mild, grade-1 changes. Patients who developed arthritis were significantly older at the time of surgery.²⁸ That is a reassuring finding for younger patients, though it means anyone undergoing the procedure should expect periodic imaging down the road to track joint health.

There is also a psychological dimension that does not get enough attention. Research on patients more than two years out from Bankart repair found that pain and functional limitation were strongly associated with fear-avoidance thinking, the tendency to avoid movement because you expect it to cause injury or pain. This association held even after accounting for the presence of a Hill-Sachs lesion and symptoms of anxiety or depression.²⁹ The practical takeaway is that recovering from a shoulder dislocation and its associated bony damage is not purely a structural problem. People who remain anxious about re-dislocation may guard their shoulder in ways that limit function long after the anatomy has been adequately repaired. Addressing that fear, whether through graded exposure in physical therapy or formal psychological support, can make a real difference in outcomes.