A Hill–Sachs lesion, or Hill–Sachs fracture, is a cortical depression in the posterolateral

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

of the

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

. It results from forceful impaction of the humeral head against the anteroinferior

glenoid The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from , "socket", reflecting the shoulder joint's ball-and-socket form. It is a shallow, pyrif ...

rim when the shoulder is dislocated anteriorly.

Signs and symptoms

Pain while rotating joint bones sounds of rotating bone joints Recurrent dislocation of shoulder Apprehension sign

Causes

The lesion is associated with anterior

shoulder dislocation A dislocated shoulder is a condition in which the head of the humerus is detached from the glenoid fossa. Symptoms include shoulder pain and instability. Complications may include a Bankart lesion, Hill-Sachs lesion, rotator cuff tear, or i ...

. When the humerus is driven from the

glenoid cavity The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from , "socket", reflecting the shoulder joint's ball-and-socket form. It is a shallow, pyri ...

, its relatively soft head impacts against the anterior edge of the

. The result is a divot or flattening in the posterolateral aspect of the

humeral head The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of ...

, usually opposite the

coracoid process The coracoid process (from Greek κόραξ, raven) is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula (hence: coracoid, or "like a raven's beak"). Pointing laterally forward, it, together with the ...

. The mechanism which leads to shoulder dislocation is usually traumatic but can vary, especially if there is history of previous dislocations.

Sports Sport is a physical activity or game, often competitive and organized, that maintains or improves physical ability and skills. Sport may provide enjoyment to participants and entertainment to spectators. The number of participants in ...

, falls,

seizures A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

, assaults, throwing, reaching, pulling on the arm, or turning over in bed can all be causes of anterior dislocation.

Diagnosis

Diagnosis can be suspected by

history History is the systematic study of the past, focusing primarily on the Human history, human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some t ...

and

physical examination In a physical examination, medical examination, clinical examination, or medical checkup, a medical practitioner examines a patient for any possible medical signs or symptoms of a Disease, medical condition. It generally consists of a series of ...

which is usually followed by imaging. Because of the mechanism of injury, apprehension of anterior dislocation is common with provocative maneuvers. Hill–Sachs lesions have been classified as "engaging" or "non-engaging", with engaging lesions defined by the ability of the glenoid to sublux into the humeral head defect during abduction and external rotation. Engaging dislocations have a higher risk of recurrent anterior dislocation, and their presence can help guide surgical management. Imaging diagnosis conventionally begins with plain film

radiography Radiography is an imaging technology, imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiog ...

. Generally, anteroposterior (AP) radiographs of the shoulder with the arm in internal rotation offer the best yield while axillary views and AP radiographs with external rotation tend to obscure the defect. However, pain and tenderness in the injured joint make appropriate positioning difficult and in a recent study of plain film x-ray for Hill–Sachs lesions, the sensitivity was only about 20%. i.e. the finding was not visible on plain film x-ray about 80% of the time. By contrast, studies have shown the value of

ultrasonography Medical ultrasound includes diagnostic techniques (mainly imaging) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, ...

in diagnosing Hill–Sachs lesions. In a population with recurrent dislocation using findings at surgery as the gold standard, a sensitivity of 96% was demonstrated. In a second study of patients with continuing shoulder instability after trauma, and using double contrast CT as a gold standard, a sensitivity of over 95% was demonstrated for ultrasound. It should be borne in mind that in both those studies, patients were having continuing problems after initial injury, and therefore the presence of a Hill–Sachs lesion was more likely. Nevertheless, ultrasonography, which is noninvasive and free from

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

, offers important advantages.

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

has also been shown to be highly reliable for the diagnosis of Hill-Sachs (and

Bankart A Bankart lesion is a type of shoulder injury that occurs following a dislocated shoulder. It is an injury of the anterior (inferior) glenoid labrum of the shoulder. When this happens, a pocket at the front of the glenoid forms that allows the hu ...

) lesions. One study used challenging methodology. First of all, it applied to those patients with a single, or first time, dislocation. Such lesions were likely to be smaller and therefore more difficult to detect. Second, two radiologists, who were blinded to the surgical outcome, reviewed the MRI findings, while two orthopedic surgeons, who were blinded to the MRI findings, reviewed videotapes of the arthroscopic procedures. Coefficiency of agreement was then calculated for the MRI and arthroscopic findings and there was total agreement (

kappa Kappa (; uppercase Κ, lowercase κ or cursive ; , ''káppa'') is the tenth letter of the Greek alphabet, representing the voiceless velar plosive sound in Ancient and Modern Greek. In the system of Greek numerals, has a value of 20. It was d ...

= 1.0) for Hill-Sachs and Bankart lesions.

Treatment

The decision to repair of the Hill–Sachs lesion is based on its association with continuing symptoms and instability. This is particularly important in patients below 25 year of age and in throwing athletes. The role of the Hill-Sachs in continuing symptoms, in turn, may be related to its width and depth, particularly if involving greater than 20% of the articular surface. Associated bony lesions or fractures may coexist in the glenoid such as the bony Bankart lesion. In such scenarios, surgical repair may include bony augmentation, a common example of which is the

Latarjet procedure The Latarjet operation, also known as the Latarjet-Bristow procedure, is a surgical procedure used to treat recurrent shoulder dislocations, typically caused by bone loss or a fracture of the glenoid. The procedure was first described by French su ...

. Additional lesions such as a Bankart,

SLAP tear A SLAP tear or SLAP lesion is an injury to the superior glenoid labrum (fibrocartilaginous rim attached around the margin of the glenoid cavity in the shoulder blade) that initiates in the back of the labrum and stretches toward the front into the ...

, or biceps injury may also be present.

Incidence

The incidence of Hill–Sachs lesion is not known with certainty. It has been reported to be present in 40% to 90% of patients presenting with anterior shoulder instability, that is subluxation or dislocation. In those who have recurrent events, it may be as high as 100%. Its presence is a specific sign of dislocation and can thus be used as an indicator that dislocation has occurred even if the joint has regained its normal alignment. Large, engaging Hill-Sachs fractures can contribute to shoulder instability and will often cause painful clicking, catching, or popping. The average depth of Hill–Sachs lesion has been reported as 4.1 mm.

Eponym

The lesion is named after Harold Arthur Hill (1901–1973) and Maurice David Sachs (1909–1987), two radiologists from San Francisco, USA. In 1940, they published a report of 119 cases of shoulder dislocation and showed that the defect resulted from direct compression of the humeral head. Before their paper, although the fracture was already known to be a sign of shoulder dislocation, the precise mechanism was uncertain.

References

Hill-Sachs lesions (frontal X-ray)
- szote.u-szedeg.hu. * http://www.shoulderus.com/ultrasound-of-the-shoulder/proximal-humerus-fracture-ultrasound-hill-sachs-lesion {{DEFAULTSORT:Hill-Sachs lesion Injuries of shoulder and upper arm Musculoskeletal disorders Orthopedic problems Lesions