Medical contributor:
First revision: 
Second revision: There are several bony defects which can lead to shoulder instability and subsequently to shoulder dislocation, some with a higher occurence than others. One of the more common ones is called a Hill-Sachs lesion, and in this article, we will discuss more in-depth about what this is.
A Hill-Sachs lesion, or Hill-Sachs deformity, is a defect of the humeral bone, which is the bone found in your upper arm. This defect is often linked with shoulder instability. This type of lesion has been linked with 67 to 93% of anterior shoulder dislocations.1 An anteriorly dislocated shoulder is where the upper arm has come out of the shoulder socket forwards. Repeated dislocation will become problematic over time, as the shoulder structures responsible for keeping it in place can become progressively injured, leading to its instability.2
The Hill-Sachs lesion is typically associated with a dent in the bone where the humerus presses against the socket as it is dislocated, as well as with potential other pathologies (e.g., Bankart Lesion) which should be identified by the clinician for proper management.2 Let us now explore causes, and symptoms, as well as diagnosis and management of the Hill-Sachs deformity.
Overview
More than 90% of shoulder dislocations happen anteriorly, and a Hill-Sachs lesion can be found in up to 93% of these. Despite the incidence being close to 100%, it remains a challenge for clinicians to determine which of the dislocations happen because of the deformity itself, or are incidental. There is limited consensus in the literature over the size of the defect that will cause shoulder joint instability or the joint position that could lead to the dislocation, which is why this can be difficult to diagnose.1
Causes of a hill sachs lesion
There are three main causes of the Hill-Sachs lesion:
Anterior shoulder instability: Approximately 47% of the lesions are associated with an already existing shoulder instability (these can happen, for example, after trauma or repetitive movements of the shoulder, such as found in certain sports).3
Bankart lesion: This is a type of lesion of one of the shoulder ligaments, and it usually happens following a dislocated shoulder. It is 2.5 times more likely that someone who has this type of lesion will experience the Hill-Sachs lesion as well.4
Anterior glenoid bone loss: This can happen after trauma to the shoulder, the glenoid being part of the shoulder socket.1
Signs and symptoms of a hill sachs lesion
As with most medical conditions, the first sign would be local discomfort in the affected shoulder joint. The medical professional will likely ask the patient their level of discomfort, the frequency of shoulder dislocation they have experienced before, and the presence of neurological symptoms if any (tingling sensation, numbness).
The medical professional will likely ask about the existence of any precipitating factors which might lead to shoulder dislocation, such as
- Recurrent falls (for example, in the elderly)
- Participating in activities which require specific external rotation movements of the arm (these can lead to shoulder dislocation and are associated with certain sports and physical activities)
- Other medical conditions, such as ones causing seizures.
When your doctor evaluates the affected shoulder, they will most likely perform a series of tests to determine the correct diagnosis. One such test is called ‘the load and shift test’, by which the trained professional will manually shift the shoulder anteriorly. If grinding is felt, it is likely due to a bony defect which is a Hill-Sachs lesion, causing rough contact on the shoulder joint. During the physical examination, the medical professional will compare the affected shoulder with the contralateral shoulder.1,5
Management and treatment for a hill sachs lesion
Management of a Hills-Sachs can be either surgical or non-surgical.
Non surgical management
Non-surgical management of the Hills-Sachs lesion works particularly well when the bony defect is relatively small. It is also likely for an anterior dislocation to undergo non-surgical management if this is the first time it has happened.1
Patients who have a significant hills sachs lesion but also have other diseases or comorbidities may not be suitable for surgery and will also be treated non-surgically.1
Surgical management
Some patients will need to undergo surgery. The clinician will be able to tell which patients need surgery based on clinical evaluation, including symptom severity and size of the lesion.1
Diagnosis
The way bony defects are diagnosed is by using imaging techniques. There are multiple ways to diagnose a humeral defect by using imaging modalities, e.g. radiography, computerised tomography (CT scans) or magnetic resonance imaging (MRI). There are advantages and disadvantages which come with each one of these techniques. Radiographers are usually more cost-effective and rapid to perform and interpret; however, CT and MRI are superior forms of imaging for diagnosing a Hills-Sachs defect, as up to 60% of bony defects can be missed by interpreting a radiograph on its own.1,6
FAQs
How can I prevent a hill sachs lesion?
As Hills-Sachs lesions happen following a dislocated shoulder, there is little one can do to prevent these, apart from preventing accidents such as falls or sports injuries from happening.
How common is a hill sachs lesion?
It has been demonstrated that the Hills-Sachs lesion was linked with 67 to 93% of anterior shoulder dislocations.1
Who is at risk of a hill sachs lesion?
As accidents such as falls or trauma can cause dislocated shoulders, anyone is at risk of developing Hills-Sachs lesions. There are certain groups in which there is a higher prevalence, such as athletes who play contact sports.
When should I see a doctor?
You should go to the emergency room after you have experienced trauma to your shoulder and you believe you have sustained a dislocated shoulder.
Summary
Bony defects in the shoulder joint, including the Hills-Sachs lesion, are issues which can cause severe shoulder instability and can lead to shoulder dislocations. Hills-Sachs lesions are more common when a patient suffers an anterior dislocation. Because of this, it is of high importance that the treating physician conducts a thorough clinical examination and uses appropriate diagnosing tools to assess the size of the lesion, which will lead to management. When the lesion is large, it is important to treat it surgically to prevent further shoulder dislocations.1
References
- Fox JA, Sanchez A, Zajac TJ, Provencher MT. Understanding the hill-sachs lesion in its role in patients with recurrent anterior shoulder instability. Curr Rev Musculoskelet Med [Internet]. 2017 Nov 3 [cited 2023 Jul 6];10(4):469–79. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5685959/
- Provencher MT, Frank RM, Leclere LE, Metzger PD, Ryu JJ, Bernhardson A, et al. The Hill-Sachs lesion: diagnosis, classification, and management. J Am Acad Orthop Surg. 2012 Apr;20(4):242–52.
- Calandra JJ, Baker CL, Uribe J. The incidence of Hill-Sachs lesions in initial anterior shoulder dislocations. Arthroscopy: The Journal of Arthroscopic & Related Surgery [Internet]. 1989 Dec 1 [cited 2023 Jul 6];5(4):254–7. Available from: https://www.sciencedirect.com/science/article/pii/0749806389901382
- Widjaja AB, Tran A, Bailey M, Proper S. Correlation between Bankart and hill-sachs lesions in anterior shoulder dislocation. ANZ J Surg [Internet]. 2006 Jun [cited 2023 Jul 6];76(6):436–8. Available from: https://onlinelibrary.wiley.com/doi/10.1111/j.1445-2197.2006.03760.x
- Lynch JR, Clinton JM, Dewing CB, Warme WJ, Matsen FA. Treatment of osseous defects associated with anterior shoulder instability. J Shoulder Elbow Surg. 2009;18(2):317–28.
- Bishop JY, Jones GL, Rerko MA, Donaldson C, MOON Shoulder Group. 3-D CT is the most reliable imaging modality when quantifying glenoid bone loss. Clin Orthop Relat Res. 2013 Apr;471(4):1251–6.
