Joint Dislocations — MCQs

10 questions

A patient fell off a bicycle and now complains of pain around the hip, with shortening of the affected limb. The hip is held in a position of flexion, adduction, and internal rotation. What is the most likely diagnosis?

Lateral dislocation of the patella is prevented by

Hill-Sach's lesion is seen in:

Traumatic anterior dislocation of shoulder with sensory loss in lateral side of forearm and weakness of flexion of elbow joint, most likely injured nerve is:

Which of the following attitudes will be seen in a patient with posterior dislocation of the hip?

Palpable femur head on per rectal exam is a feature of which of the following conditions?

Patient with shoulder dislocation has axillary nerve injury. Which movement will be most affected?

What is a late complication of elbow dislocation?

A 30-year-old male presents with pain and limited movement in his shoulder following a fall. X-ray reveals an anterior dislocation of the glenohumeral joint. Which of the following structures is most likely to be damaged in this injury?

Q10

Tennis player can spontaneously reduce a shoulder dislocation. He can do it again and again himself. He is suffering from?

Joint Dislocations Indian Medical PG Practice Questions and MCQs

Question 1: A patient fell off a bicycle and now complains of pain around the hip, with shortening of the affected limb. The hip is held in a position of flexion, adduction, and internal rotation. What is the most likely diagnosis?

A. Intertrochanteric fracture (IT fracture)
B. Transcervical fracture
C. Posterior dislocation (Correct Answer)
D. Anterior dislocation

Explanation: **Posterior dislocation** - **Posterior hip dislocations** typically occur after high-energy trauma (e.g., falls from height, motor vehicle accidents) and present with the affected limb in a classic position of **flexion, adduction, and internal rotation**. - **Shortening of the limb** is also a hallmark sign, often due to the femoral head displacing posteriorly and superiorly. *Intertrochanteric fracture (IT fracture)* - **Intertrochanteric fractures** usually present with the affected limb in **external rotation** and shortening, which is contrary to the internal rotation described in the case. - While pain is present, the specific rotational deformity helps differentiate it from a hip dislocation. *Transcervical fracture* - **Transcervical fractures** (femoral neck fractures) also typically present with the leg in **external rotation** and shortening. - These fractures are common in older adults and often associated with less severe trauma or falls. *Anterior dislocation* - **Anterior hip dislocations** are less common and typically present with the affected limb in a position of **flexion, abduction, and external rotation**. - This presentation is directly opposite to the adduction and internal rotation described in the question.

Question 2: Lateral dislocation of the patella is prevented by

A. Vastus medialis (Correct Answer)
B. Rectus femoris
C. Vastus lateralis
D. Vastus intermedius

Explanation: **_1. Vastus medialis_** - The **vastus medialis** muscle, particularly its oblique fibers (**vastus medialis obliquus**), is crucial in preventing **lateral patellar subluxation or dislocation** by pulling the patella medially. - Weakness or dysfunction of the vastus medialis, especially relative to the vastus lateralis, can predispose individuals to **patellofemoral instability**. *2. Rectus femoris* - The **rectus femoris** is one of the quadriceps muscles, primarily responsible for **knee extension** and hip flexion. - While it contributes to overall patella stability, it does not specifically prevent **lateral dislocation** as effectively as the vastus medialis. *3. Vastus lateralis* - The **vastus lateralis** is part of the quadriceps and primarily pulls the patella **laterally**. - An overactive or dominant vastus lateralis can actually **contribute to lateral patellar tracking problems** and dislocation. *4. Vastus intermedius* - The **vastus intermedius** lies deep to the rectus femoris and is mainly involved in **knee extension**. - It has a central pull on the patella and does not have a significant role in preventing **lateral patella displacement**.

Question 3: Hill-Sach's lesion is seen in:

A. Anterior dislocation of hip
B. Posterior dislocation of hip
C. Recurrent dislocation of shoulder (Correct Answer)
D. Posterior dislocation of shoulder

Explanation: ***Recurrent dislocation of shoulder*** - A **Hill-Sach's lesion** is a **compression fracture** of the posterolateral part of the humeral head, occurring as the humeral head impacts the anterior rim of the glenoid during **anterior shoulder dislocation**. - It is particularly associated with **recurrent anterior shoulder dislocations** due to repeated impaction. *Anterior dislocation of hip* - This condition involves the femoral head moving anteriorly out of the acetabulum and is not associated with a Hill-Sach's lesion. - While it causes significant pain and immobility, the specific bone lesion known as Hill-Sach's involves the humerus, not the femur. *Posterior dislocation of hip* - A posterior hip dislocation involves the femoral head moving posteriorly out of the acetabulum and is not linked to a Hill-Sach's lesion. - This type of injury is often seen in high-impact trauma, such as car accidents, and can be associated with acetabular fractures or sciatic nerve injury. *Posterior dislocation of shoulder* - This involves the humeral head dislocating posteriorly relative to the glenoid, and while bone lesions can occur, they are typically **reverse Hill-Sach's lesions** (on the anterior aspect of the humeral head) or **bony Bankart lesions** of the posterior glenoid. - A standard Hill-Sach's lesion specifically refers to the posterolateral humeral head defect seen in **anterior dislocations**.

Question 4: Traumatic anterior dislocation of shoulder with sensory loss in lateral side of forearm and weakness of flexion of elbow joint, most likely injured nerve is:

A. Ulnar nerve
B. Axillary nerve
C. Radial nerve
D. Musculocutaneous nerve (Correct Answer)

Explanation: ***Musculocutaneous nerve*** - The **musculocutaneous nerve** innervates the biceps brachii and brachialis muscles, responsible for **elbow flexion**. - It also provides sensory innervation to the **lateral forearm** via the **lateral cutaneous nerve of the forearm**, explaining the sensory loss described. *Ulnar nerve* - The ulnar nerve primarily innervates muscles of the **hand** and gives sensory supply to the medial 1 and 1/2 digits. - Its injury would typically lead to weakness in **finger adduction/abduction** and sensory loss in the medial hand, not the lateral forearm. *Axillary nerve* - The axillary nerve innervates the **deltoid** and **teres minor** muscles, causing weakness in **shoulder abduction** and external rotation upon injury. - Sensory loss would be over the **regimental badge area** (lateral shoulder), not the lateral forearm. *Radial nerve* - The radial nerve innervates the **extensor muscles of the wrist and fingers**, and the triceps. - Injury would result in **wrist drop** and sensory loss over the **posterior arm, forearm, and hand**, not lateral forearm sensory loss.

Question 5: Which of the following attitudes will be seen in a patient with posterior dislocation of the hip?

A. Flexion, Adduction, External rotation
B. Flexion, Adduction, Internal rotation (Correct Answer)
C. Flexion, Abduction, Internal rotation
D. Flexion, Abduction, External rotation

Explanation: ***Flexion, Adduction, Internal rotation*** - In a posterior hip dislocation, the femoral head is forced posteriorly and superiorly, causing the limb to assume a characteristic position of **flexion**, **adduction**, and **internal rotation**. - This position is due to the **unresisted pull of hip adductors and internal rotators** when the femoral head is out of the acetabulum posteriorly. *Flexion, Adduction, External rotation* - While **flexion** and **adduction** can be present, **external rotation** is characteristic of an **anterior hip dislocation**, where the femoral head dislocates anteriorly and inferiorly. - This attitude is also commonly seen in patients with an **acetabular fracture** since the muscles that externally rotate the hip are unopposed. *Flexion, Abduction, Internal rotation* - **Flexion** and **internal rotation** can be seen in posterior dislocations, but **abduction** is typically not present; instead, the hip is adducted. - **Abduction** would indicate that the limb is moved away from the midline, which is contrary to the typical posture in posterior dislocation. *Flexion, Abduction, External rotation* - This combination is characteristic of an **anterior hip dislocation**, where the femoral head dislocates anteriorly and is often associated with the limb being in **flexion**, **abduction**, and **external rotation**. - The patient's leg is held away from the body (abduction) and turned outwards (external rotation), which is not consistent with a posterior dislocation.

Question 6: Palpable femur head on per rectal exam is a feature of which of the following conditions?

A. Inferior hip dislocation
B. Central hip dislocation
C. Posterior hip dislocation (Correct Answer)
D. Anterior hip dislocation

Explanation: ***Posterior hip dislocation*** - In **posterior hip dislocation**, the femoral head is displaced posteriorly and superiorly, often lying in the **gluteal region**. - A palpable femoral head on **per rectal exam** suggests the head has displaced medially enough to be felt through the rectal wall, which can occur in severe posterior dislocations where the head impinges on the pelvis. *Inferior hip dislocation* - In **inferior hip dislocation**, the femoral head displaces **inferiorly and anteriorly**, often lying below the acetabulum. - The femoral head would typically be palpable in the **perineum** or groin, not via per rectal exam. *Central hip dislocation* - **Central hip dislocation** involves the femoral head pushing through the **acetabular floor** into the pelvis. - This type of dislocation causes internal displacement, but the femoral head would not typically be palpable per rectally as it remains contained within the acetabular breach, rather it would be the **pelvic fracture** that would be palpable. *Anterior hip dislocation* - In **anterior hip dislocation**, the femoral head displaces **anteriorly**, often into the obturator foramen or pubic region. - The femoral head would be palpable in the **groin** or anterior thigh, not through a per rectal exam.

Question 7: Patient with shoulder dislocation has axillary nerve injury. Which movement will be most affected?

A. Forward Flexion
B. Internal Rotation
C. Shoulder Abduction (Correct Answer)
D. External Rotation

Explanation: ***Shoulder Abduction*** - The **axillary nerve** innervates the **deltoid muscle**, which is the primary muscle responsible for **shoulder abduction** beyond the initial 15 degrees. - Injury to this nerve would significantly impair the patient's ability to lift their arm away from their body. *Forward Flexion* - **Forward flexion** of the shoulder is primarily carried out by the **anterior deltoid**, **pectoralis major**, and **coracobrachialis muscles**. - While the anterior deltoid is affected, other muscles can still contribute to this movement, making it less severely impaired than abduction. *Internal Rotation* - **Internal rotation** is largely controlled by the **subscapularis**, **latissimus dorsi**, **teres major**, and **pectoralis major**. - These muscles are not innervated by the axillary nerve, so internal rotation would be largely preserved. *External Rotation* - **External rotation** is primarily performed by the **infraspinatus** and **teres minor muscles**. - These muscles are supplied by the **suprascapular nerve** and **axillary nerve** (for teres minor), respectively, but the deltoid's role is minimal, so overall external rotation would be less affected compared to abduction.

Question 8: What is a late complication of elbow dislocation?

A. Median nerve injury
B. Brachial artery injury
C. Myositis ossificans (Correct Answer)
D. None of the options

Explanation: **Myositis ossificans** - **Myositis ossificans** is the abnormal formation of **heterotopic bone** within muscle or other soft tissues, often developing weeks to months after joint trauma such as an elbow dislocation. - It typically presents as a painful, firm mass with restricted joint movement, especially **flexion** and **extension** at the elbow. *Median nerve injury* - **Median nerve injury** can occur at the time of the initial elbow dislocation (an **acute complication**), but it is not typically considered a late complication that develops over weeks or months. - Symptoms include numbness in the thumb, index, and middle fingers, as well as weakness in **thumb opposition** and **flexion** of the index finger. *Brachial artery injury* - **Brachial artery injury** is an **acute complication** of severe elbow dislocation, leading to compromise of distal blood flow. - Signs include absence of pulses, pallor, paresthesia, and pain in the forearm and hand, requiring immediate surgical intervention. *None of the options* - This option is incorrect because **myositis ossificans** is a well-recognized late complication of elbow dislocation.

Question 9: A 30-year-old male presents with pain and limited movement in his shoulder following a fall. X-ray reveals an anterior dislocation of the glenohumeral joint. Which of the following structures is most likely to be damaged in this injury?

A. Long head of biceps tendon
B. Acromioclavicular ligament
C. Supraspinatus tendon
D. Anterior inferior glenohumeral ligament (Correct Answer)
E. Coracoclavicular ligament

Explanation: ***Anterior inferior glenohumeral ligament*** - This ligament is a primary static stabilizer against **anterior dislocation** of the shoulder; thus, it is frequently stretched or torn during such an event. - Damage to this ligament is often associated with a **Bankart lesion**, which is an injury to the anterior inferior labrum that can lead to recurrent dislocations. *Long head of biceps tendon* - While the **long head of the biceps tendon** can be injured in shoulder trauma, it is more commonly associated with chronic overuse or superior labral tears (**SLAP lesions**), rather than primary anterior dislocation. - Injuries to this tendon might occur as a secondary complication but are not the most likely primary soft tissue damage in an acute anterior dislocation. *Acromioclavicular ligament* - The **acromioclavicular ligament** stabilizes the **acromioclavicular (AC) joint**, which is distinct from the glenohumeral joint. - Injuries to this ligament typically result from direct trauma to the top of the shoulder, causing AC joint separation, not glenohumeral dislocation. *Supraspinatus tendon* - The **supraspinatus tendon** is part of the rotator cuff and is most commonly injured in impingement syndrome or rotator cuff tears, which can result from falls but are not the primary structure damaged in an **anterior glenohumeral dislocation**. - Its role is mainly in abduction of the arm, and while it can be involved in large tears associated with advanced age, it is not the initial or most common structure to fail in this specific injury. *Coracoclavicular ligament* - The **coracoclavicular ligament** is composed of the conoid and trapezoid ligaments, which are crucial for the stability of the **acromioclavicular (AC) joint**. - Injury to this ligament is indicative of a more severe AC joint separation (usually **type III or higher**) and is not the primary structure damaged in a glenohumeral dislocation.

Question 10: Tennis player can spontaneously reduce a shoulder dislocation. He can do it again and again himself. He is suffering from?

A. Inferior shoulder dislocation
B. Fracture upper end humerus
C. Acute shoulder dislocation
D. Recurrent shoulder dislocation (Correct Answer)

Explanation: ***Recurrent shoulder dislocation*** - The ability to **spontaneously reduce** a shoulder dislocation, and the history of it happening "again and again" strongly indicate **recurrent shoulder dislocation**. - This condition often results from **ligamentous laxity** or damage to the **labrum** (Bankart lesion) that fails to stabilize the shoulder joint after an initial dislocation. *Inferior shoulder dislocation* - This is a **specific type of shoulder dislocation** (luxatio erecta) where the humeral head is displaced inferiorly, but "inferior" alone does not explain the recurrent nature. - While possible in an individual, the key element here is the **recurrence** and self-reduction, not just the direction of a single dislocation. *Fracture upper end humerus* - A fracture of the upper end of the humerus is a **bony injury** and would typically present with severe pain, swelling, and inability to move the arm, not spontaneous reduction. - This injury would usually **prevent** the patient from repeatedly dislocating and reducing their shoulder. *Acute shoulder dislocation* - An acute shoulder dislocation refers to a **single, recent episode** of dislocation. - The patient's repeated ability to self-reduce the shoulder indicates a chronic problem rather than an initial, isolated event.

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