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Radial Head Fractures: Symptoms, Diagnosis & Recovery

FRCS Prep: Mastering Radial Head Fractures - Case Guide

23 Apr 2026 80 min read 138 Views
Illustration of fractures of the radial - Dr. Mohammed Hutaif

Key Takeaway

We review everything you need to understand about FRCS Prep: Mastering Radial Head Fractures - Case Guide. Managing minimally displaced fractures of the radial head involves a complete history, examination, pain relief, and immobilization with a collar and cuff. Early movement and physiotherapy are crucial, with a 2-week follow-up. Surgical intervention for fractures of the radial is considered for complex elbow fracture dislocations where joint stability is compromised.

Comprehensive Exam


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Question 1

A 45-year-old male sustains a fall onto an outstretched hand, resulting in a radial head fracture. Radiographs show a displaced, comminuted fracture involving 40% of the articular surface with a 3mm step-off, but no mechanical block to forearm rotation. Which Mason-Johnston classification best describes this injury?





Explanation

Mason-Johnston Type III fractures are characterized by significant comminution and/or displacement, often involving more than 30% of the articular surface and/or displacement of more than 2mm, or with mechanical block. While a Type II involves a single displaced fragment, a Type III implies more extensive disruption, typically precluding successful closed reduction and often requiring surgical intervention. Type I is a non-displaced crack. Type IV involves an associated elbow dislocation.

Question 2

A 30-year-old male presents with persistent wrist pain and instability following a radial head fracture managed non-operatively 6 weeks ago. Initial radiographs showed a Mason-Johnston Type II radial head fracture. On examination, there is tenderness over the distal radio-ulnar joint (DRUJ) and a positive 'shuck test' at the wrist. What is the most likely underlying diagnosis causing these new symptoms?





Explanation

The combination of a radial head fracture, interosseous membrane disruption (leading to proximal radial migration), and distal radio-ulnar joint (DRUJ) injury (manifested by wrist pain and instability/positive shuck test) constitutes an Essex-Lopresti lesion. This severe injury often leads to chronic pain and dysfunction if not recognized and treated appropriately, typically with radial head replacement and potentially DRUJ stabilization. Radial head non-union might cause local pain but wouldn't explain DRUJ instability. Heterotopic ossification and LCL insufficiency are elbow-centric and wouldn't directly cause DRUJ instability in this context. Cubital tunnel syndrome is a nerve compression issue.

Question 3

A 62-year-old female presents with a Mason-Johnston Type II radial head fracture with 2mm displacement and a palpable block to terminal forearm pronation. There is no associated elbow dislocation or other obvious ligamentous injury. What is the most appropriate initial management strategy?





Explanation

A Mason-Johnston Type II fracture with a mechanical block to forearm rotation (even with only 2mm displacement) is a strong indication for surgical intervention, typically ORIF if the fragment is amenable. The mechanical block signifies impingement of the displaced fragment, which will prevent full range of motion and lead to chronic dysfunction if not addressed. Sling immobilization alone is insufficient. Radial head excision is generally reserved for severely comminuted fractures not amenable to ORIF, or in low-demand patients, and can lead to proximal radial migration and DRUJ issues. Radial head replacement is typically indicated for highly comminuted (Type III/IV) fractures not reconstructible, or in Essex-Lopresti injuries. Attempting closed reduction is unlikely to succeed with a palpable block from a displaced articular fragment.

Question 4

Which of the following associated injuries is most commonly missed in the initial evaluation of an isolated radial head fracture?





Explanation

While all listed injuries can occur with radial head fractures, DRUJ instability, indicative of an Essex-Lopresti lesion or other forearm axis disruption, is often missed initially. It presents as insidious wrist pain and instability that becomes apparent days or weeks after the initial injury to the radial head. Coronoid and MCL injuries are typically associated with terrible triad injuries involving elbow dislocation. Capitellum chondral injuries are less common and often only seen on arthroscopy or MRI. Olecranon fractures are usually obvious on initial X-rays.

Question 5

A 55-year-old painter presents with a Mason-Johnston Type III radial head fracture with 4 fragments, involving 60% of the articular surface. He is very active and desires a full return to function. There is no associated elbow dislocation. What is the preferred surgical option to restore function and stability?





Explanation

For highly comminuted (Mason-Johnston Type III or IV) radial head fractures, particularly in active patients where restoration of articular congruity and preservation of radial length are critical, radial head replacement is often the preferred surgical option. ORIF may be difficult or impossible with 4 fragments involving 60% of the articular surface. Radial head excision can lead to proximal radial migration and DRUJ issues, especially in younger, active patients. Arthrodesis is a salvage procedure for end-stage arthritis or instability, not a primary option for acute fractures. Non-operative management is not appropriate for a significantly comminuted, displaced Type III fracture in an active individual.

Question 6

What is the primary concern when considering radial head excision for a comminuted radial head fracture in a young, active patient?





Explanation

The primary concern with radial head excision, especially in younger, active patients, is the loss of longitudinal stability of the forearm, leading to proximal migration of the radius and subsequent distal radio-ulnar joint (DRUJ) instability. This can cause significant wrist pain and dysfunction. While elbow stiffness and heterotopic ossification are potential complications of any elbow trauma or surgery, proximal migration and DRUJ issues are specific and major drawbacks of radial head excision.

Question 7

Which of the following is an absolute contraindication for radial head excision in the management of a radial head fracture?





Explanation

Associated interosseous membrane disruption, characteristic of an Essex-Lopresti lesion, is an absolute contraindication for radial head excision. In these cases, the radial head plays a critical role in longitudinal forearm stability. Removing it would exacerbate proximal radial migration, leading to severe DRUJ disruption and chronic wrist pain. In such scenarios, radial head replacement is indicated to restore length and stability. Concomitant distal radius fracture is a relative contraindication but not absolute. Older, low-demand patients might be candidates for excision in certain scenarios. Previous elbow surgery is a relative consideration, and a Type II fracture may be amenable to ORIF or, in some cases, excision if small and non-reconstructible, but it is not an absolute contraindication.

Question 8

A 28-year-old male sustains a Mason-Johnston Type IV radial head fracture with a posterior elbow dislocation. After successful closed reduction of the elbow, radiographs show significant comminution of the radial head. What is the most appropriate next step in management?





Explanation

A Mason-Johnston Type IV fracture with elbow dislocation (often part of a 'terrible triad' if coronoid and LCL are also injured) requires careful management. After reduction of the dislocation, the radial head injury needs to be addressed to restore stability and function. Given significant comminution in an active 28-year-old, radial head replacement is often the best option to restore radial length and provide buttress to the lateral elbow, preventing recurrent instability. Concurrently, the elbow's stability, especially regarding the LCL and potentially MCL, must be assessed. ORIF would be challenging with significant comminution. Excision is contraindicated due to the high risk of instability. Non-operative management or casting would not address the inherent instability caused by the radial head comminution in this severe injury.

Question 9

Which surgical approach provides the best exposure for ORIF of a radial head fracture while minimizing the risk to the posterior interosseous nerve (PIN)?





Explanation

The posterolateral approach, also known as the Kocher approach, is widely preferred for radial head fractures. It uses the interval between the anconeus and extensor carpi ulnaris (ECU) muscles. This approach protects the posterior interosseous nerve (PIN), which typically lies within the supinator muscle, distal and anterior to the radial head. The anterior (Henry) approach risks the PIN more directly, and medial or direct posterior approaches are generally not suitable for radial head fixation. The lateral approach with anconeus muscle split is similar to Kocher but the key is the safe interval.

Question 10

Regarding the posterior interosseous nerve (PIN) during surgical approaches to the radial head, at what point is it most vulnerable?





Explanation

The posterior interosseous nerve (PIN) is a branch of the radial nerve. It becomes vulnerable as it enters and passes through the supinator muscle (often referred to as the Arcade of Frohse, the proximal edge of the superficial head of the supinator). During surgical approaches to the radial head, particularly if the dissection extends too far anterior or distal, the PIN can be at risk, especially where it pierces the superficial head of the supinator muscle within the radial tunnel. This is why the Kocher approach, staying posterior, is preferred.

Question 11

What is the primary role of the interosseous membrane (IOM) in forearm stability?





Explanation

The interosseous membrane (IOM) is crucial for longitudinal forearm stability, particularly in transmitting axial loads from the radius to the ulna. It acts as a primary load-bearing structure between the two bones, especially during activities involving compression through the hand. It doesn't primarily prevent valgus instability (that's MCL's role), resist pronation, or directly stabilize the DRUJ (though its disruption leads to DRUJ issues), nor is it for biceps attachment.

Question 12

When performing open reduction and internal fixation (ORIF) of a radial head fracture, what is the ideal placement for fixation screws to minimize impingement with the capitellum during forearm rotation?





Explanation

To avoid impingement of hardware against the capitellum, screws and plates should ideally be placed in the 'safe zone' of the radial head. This zone is typically defined as the non-articulating portion of the radial head that does not articulate with the capitellum through a full range of forearm rotation. This zone is generally considered to be 110-degree arc on the radial head, typically in the posterolateral quadrant when the forearm is in neutral rotation, or approximately 90 degrees of supination to 90 degrees of pronation. Placing hardware in the anterior, posterior, or superior articulating zones is prone to impingement and pain.

Question 13

A 70-year-old sedentary patient presents with a Mason-Johnston Type III radial head fracture with severe comminution. He is not keen on extensive surgery. What is a reasonable management option to consider, accepting potential trade-offs?





Explanation

For elderly, sedentary patients with severely comminuted radial head fractures (Type III or IV) who are not candidates for ORIF or do not desire more extensive surgery like radial head replacement, radial head excision can be a reasonable option. While it carries the risk of proximal radial migration and DRUJ issues, in low-demand individuals, it can provide pain relief and improve motion with acceptable functional outcomes. ORIF is often not feasible due to comminution. Replacement is a good option but more involved surgery. Arthrodesis is a salvage procedure. Long arm casting would likely lead to severe stiffness in this age group.

Question 14

Which of the following ligaments is most commonly injured in a 'terrible triad' injury of the elbow?





Explanation

The 'terrible triad' of the elbow consists of a posterior elbow dislocation, a radial head fracture, and a coronoid process fracture. The most consistently injured ligament in this complex is the lateral ulnar collateral ligament (LUCL), which is crucial for posterolateral rotatory stability of the elbow. MCL injury can also occur, but the LUCL is the key structure disrupting posterolateral stability in this injury pattern. The annular ligament is injured as part of the radial head fracture, but the LUCL is the primary stabilizer injured in the dislocation component.

Question 15

Following open reduction and internal fixation (ORIF) of a radial head fracture, what is the primary goal of early rehabilitation?





Explanation

The primary goal of early rehabilitation after ORIF of a radial head fracture is to restore range of motion while protecting the internal fixation. Early, controlled motion helps prevent stiffness, which is a common complication of elbow injuries. Full strength comes later. While preventing heterotopic ossification is a goal, it's typically addressed with medication or radiation in high-risk cases, not solely through early rehab. Returning to sports within 2 weeks is unrealistic, and maintaining fixed flexion deformity is undesirable.

Question 16

A Mason-Johnston Type I radial head fracture typically involves:





Explanation

A Mason-Johnston Type I radial head fracture is characterized by a non-displaced crack or a minimally displaced (less than 2mm) small articular depression. There is typically no mechanical block to forearm rotation. Displaced fractures, comminution, and elbow dislocations are features of higher-grade Mason-Johnston types.

Question 17

What is the typical indication for non-operative management of a radial head fracture?





Explanation

Non-operative management, typically involving a brief period of immobilization followed by early active range of motion, is the standard for Mason-Johnston Type I radial head fractures, which are non-displaced or minimally displaced without a mechanical block to forearm rotation. All other options listed (Type III, mechanical block, elbow dislocation, Essex-Lopresti) are indications for surgical intervention.

Question 18

Which type of implant is generally preferred for radial head replacement in an acute fracture setting?





Explanation

Modular metallic implants are generally preferred for radial head replacement in acute fracture settings. They allow for independent adjustment of head size, stem diameter, and neck length, enabling the surgeon to precisely restore radial length, provide stability, and optimize contact with the capitellum. Monoblock implants offer less versatility. Bipolar implants have been used but have less favorable long-term outcomes than modular designs. Silicone implants are generally reserved for rheumatoid arthritis or reconstructive procedures, not acute fractures, and have issues with wear. Ceramic implants are less common for radial head.

Question 19

What is the primary role of the radial head in elbow stability?





Explanation

The radial head serves as a secondary stabilizer against valgus stress at the elbow, acting as a bony buttress, especially when the medial collateral ligament (MCL) is compromised. Critically, it also provides longitudinal stability to the forearm, maintaining the length relationship between the radius and ulna, which is essential for DRUJ stability and overall forearm mechanics. While it articulates to allow pronation/supination, its primary role in stability is as a secondary valgus stabilizer and longitudinal load bearer.

Question 20

A 40-year-old male undergoes radial head replacement for a complex Mason-Johnston Type III fracture. Post-operatively, he develops progressive elbow stiffness. Which complication is most likely contributing to this stiffness?





Explanation

Heterotopic ossification (HO) is a common and challenging complication after elbow trauma and surgery, especially in the context of complex fractures and dislocations. It involves the formation of new bone in soft tissues around the joint, leading to progressive loss of motion and stiffness. While infection and aseptic loosening are possible complications, HO is particularly known for causing severe stiffness after elbow surgery. Radial and ulnar nerve palsies would primarily cause neurological symptoms rather than direct stiffness.

Question 21

When assessing a radial head fracture, what radiographic view is essential to evaluate the relationship between the radial head and capitellum and to identify potential mechanical blocks?





Explanation

While AP and lateral views are standard, oblique views (specifically, the radiocapitellar view, also known as the radial head-capitellum view or Greenspan view) are crucial for thoroughly evaluating radial head fractures. These views help to unmask subtle displacement, depression, or mechanical blocks that might be obscured on standard AP or lateral projections, by rotating the forearm. They provide an 'en face' view of the radial head articular surface.

Question 22

Which nerve is at highest risk during a medial approach to the elbow, which might be considered if other structures need repair alongside a radial head fracture (e.g., MCL)?





Explanation

The ulnar nerve is the nerve at highest risk during a medial approach to the elbow. It runs in the cubital tunnel posterior to the medial epicondyle and is superficial in this region. Care must be taken to identify and protect it. Radial and median nerves are located more anterior and lateral to the medial epicondyle respectively, and are not the primary concern with a medial approach.

Question 23

A 35-year-old female presents with a Mason-Johnston Type II radial head fracture with 2mm displacement but no mechanical block. She is able to fully pronate and supinate. What is the most appropriate initial management?





Explanation

For a Mason-Johnston Type II radial head fracture with minimal displacement (2mm) and no mechanical block to forearm rotation, non-operative management with a brief period of immobilization (e.g., 1 week in a sling for comfort) followed by early active range of motion is often appropriate. Surgical intervention (ORIF, replacement, excision) is indicated if there's significant displacement, comminution, mechanical block, or associated instability. A long arm cast would lead to unnecessary stiffness.

Question 24

What is the significance of a coronoid process fracture in the context of a radial head fracture and elbow dislocation?





Explanation

A coronoid process fracture, especially when combined with a radial head fracture and elbow dislocation, is a critical component of the 'terrible triad' injury. Its presence signifies significant elbow instability. The coronoid is a key anterior stabilizer of the elbow; a fracture compromises this stability, increasing the risk of recurrent dislocation. Its presence does not contraindicate radial head replacement; rather, both may need to be addressed to restore stability.

Question 25

Which of the following describes the 'safe zone' for screw placement in the radial head when performing ORIF?





Explanation

The 'safe zone' for hardware placement in the radial head refers to the area that does not articulate with the capitellum or the lesser sigmoid notch of the ulna throughout the full range of pronation and supination. This zone is typically a 110-degree arc on the radial head, often described as the posterolateral aspect when the forearm is in neutral. Placing hardware outside this zone risks impingement, pain, and loss of motion.

Question 26

In the modified Mason-Johnston classification, what defines a Type II fracture?





Explanation

The modified Mason-Johnston classification refines the original. A Type II fracture is defined as a displaced fracture involving a single fragment that is usually amenable to fixation. It typically involves more than 2mm displacement or more than 30% of the articular surface, but is not significantly comminuted. A palpable mechanical block is an important clinical finding, often associated with a Type II or higher. Non-displaced fractures are Type I. Comminuted fractures are Type III. Fractures with associated elbow dislocation are Type IV.

Question 27

What is the main advantage of using headless compression screws for fixation of radial head fractures?





Explanation

Headless compression screws are advantageous for radial head fractures because they can be fully countersunk beneath the articular cartilage. This minimizes the risk of hardware prominence, which can lead to impingement on the capitellum or trochlea during forearm rotation, causing pain and limiting motion. They provide good compression but not necessarily superior rotational stability compared to plates. They are not always easier to remove or allow for earlier weight-bearing uniquely. Cost is not the primary surgical driver.

Question 28

A patient undergoing ORIF for a radial head fracture complains of numbness and tingling in the small and ring fingers post-operatively. Which nerve is most likely affected?





Explanation

Numbness and tingling in the small and ring fingers are characteristic symptoms of ulnar nerve compression or injury. The ulnar nerve runs posteriorly to the medial epicondyle (cubital tunnel) and can be affected by direct trauma, swelling, or surgical manipulation during elbow procedures, including those for radial head fractures, particularly if a medial approach is used or the elbow is acutely swollen/positioned. Radial and median nerves would present with different sensory deficits.

Question 29

What is the recommended timing for initiation of active range of motion exercises following non-operative management of a Mason-Johnston Type I radial head fracture?





Explanation

For Mason-Johnston Type I radial head fractures (non-displaced, no mechanical block), early active range of motion exercises should be initiated almost immediately post-injury, as tolerated by the patient. A brief period of sling immobilization (e.g., a few days for comfort) is acceptable, but prolonged immobilization should be avoided to prevent elbow stiffness, which is a common and debilitating complication of elbow injuries. Waiting for radiographic healing is too long.

Question 30

Which of the following conditions is an absolute contraindication for conservative management of a radial head fracture?





Explanation

An associated interosseous membrane injury, particularly as part of an Essex-Lopresti lesion, is an absolute contraindication for conservative management of a radial head fracture. The radial head is crucial for longitudinal forearm stability, and its disruption combined with IOM injury necessitates surgical restoration of radial length and stability, usually via radial head replacement, to prevent proximal radial migration and DRUJ disruption. Other options are relative considerations but not absolute contraindications.

Question 31

In the context of radial head fractures, what does the term 'terrible triad' refer to?





Explanation

The 'terrible triad' of the elbow is a specific and severe injury pattern characterized by a posterior elbow dislocation, a radial head fracture, and a coronoid process fracture. This combination often results in significant instability requiring surgical intervention to restore joint stability and function. Option E describes an Essex-Lopresti lesion.

Question 32

What is the approximate range of motion of forearm pronation and supination that must be preserved for most activities of daily living (ADLs)?





Explanation

Approximately 50 degrees of pronation and 50 degrees of supination are generally considered sufficient for most activities of daily living (ADLs). While a full range is desirable, this 100-degree arc of forearm rotation allows for adequate function in many tasks. Loss beyond this threshold often leads to significant functional impairment.

Question 33

What complication is specifically addressed by the 'safe zone' concept in radial head fracture fixation?





Explanation

The 'safe zone' for hardware placement directly addresses the risk of hardware impingement on the capitellum during elbow flexion-extension or on the lesser sigmoid notch of the ulna during forearm rotation. Placing screws or plates outside this non-articulating zone can lead to pain, crepitus, and mechanical block, necessitating hardware removal or revision surgery. While non-union and infection are complications, the safe zone is specifically for impingement.

Question 34

Which factor is most predictive of persistent elbow stiffness after a radial head fracture?





Explanation

The severity of the initial injury, including fracture comminution, associated ligamentous injuries, and especially concomitant elbow dislocation (as seen in terrible triad injuries), is the most significant predictor of persistent elbow stiffness. These severe injuries often involve extensive soft tissue damage, prolonged immobilization, and a higher risk of heterotopic ossification, all contributing to stiffness. While age and smoking can influence healing, the injury severity itself is paramount.

Question 35

When performing ORIF of a radial head fracture, what type of approach may risk the posterolateral rotatory stability if not carefully repaired?





Explanation

The posterolateral (Kocher) approach, while commonly used and safe for the PIN, involves detaching or splitting the anconeus muscle and reflecting the supinator. If the lateral collateral ligament complex, particularly the lateral ulnar collateral ligament (LUCL) origin, is compromised or not meticulously repaired during closure (or if it was already injured), it can destabilize the elbow against posterolateral rotatory forces. Care must be taken to repair the posterior capsule and anconeus for stability.

Question 36

What is the primary concern with a retained, unreduced, or unaddressed radial head fragment causing a mechanical block to forearm rotation?





Explanation

A retained, unreduced, or unaddressed radial head fragment causing a mechanical block to forearm rotation will inevitably lead to chronic pain and significant functional limitation due to restricted elbow and forearm range of motion. This impingement prevents smooth articulation and prevents the return of normal function. While long-term arthritis might develop, and HO is a risk, the immediate and primary concern is the mechanical blockage. Ulnar nerve palsy and infection are less directly related to the mechanical block itself.

Question 37

Which radiographic sign on a lateral elbow view might suggest an occult radial head fracture, even if the radial head itself appears intact?





Explanation

The anterior and/or posterior fat pad sign on a lateral elbow radiograph is a classic indicator of an intra-articular effusion, which strongly suggests an occult fracture in the absence of obvious bony injury. In an adult, a visible posterior fat pad is always abnormal, and an anterior fat pad (sail sign) that is elevated and prominent is also indicative of effusion. In the setting of trauma, this should prompt suspicion for a radial head or capitellum fracture, even if not directly visualized.

Question 38

What anatomical structure stabilizes the proximal radio-ulnar joint (PRUJ)?





Explanation

The annular ligament is a strong fibrous band that encircles the head of the radius, holding it in firm apposition with the radial notch of the ulna. It is the primary stabilizer of the proximal radio-ulnar joint (PRUJ), allowing for pronation and supination while maintaining joint integrity. The collateral ligaments stabilize the humeroulnar and humeroradial joints primarily, while the oblique cord is a secondary stabilizer of the forearm.

Question 39

A 25-year-old male sustains a radial head fracture after a fall. On examination, he has pain with palpation over the radial head and limited pronation/supination. Radiographs show a Mason-Johnston Type II fracture with a single displaced fragment. Which of the following is the most important factor in deciding between non-operative and operative management for this patient?





Explanation

For a Mason-Johnston Type II radial head fracture, the presence of a mechanical block to forearm rotation is the most important factor in deciding for operative management. Even a minimally displaced fragment causing a block will lead to persistent pain and stiffness if not addressed surgically. While activity level and age are considerations, a mechanical block is a direct indication for surgical intervention to restore motion. The number of fragments (single vs. comminuted) influences the type of surgery but the block indicates surgery is needed. Location matters more for fracture type (e.g., radial neck vs. head).

Question 40

What is the most common approach to assess the integrity of the interosseous membrane (IOM) when an Essex-Lopresti lesion is suspected?





Explanation

MRI of the forearm is the most effective imaging modality for directly assessing the integrity of the interosseous membrane (IOM). It can visualize tears, avulsions, or other disruptions of the IOM that are critical for diagnosing an Essex-Lopresti lesion. Standard radiographs might show proximal radial migration (indirect sign), but MRI provides direct visualization of the soft tissue injury. CT is good for bone, ultrasound is less reliable for deep IOM structures.

Question 41

In pediatric radial head fractures, what specific management consideration is crucial due to the open physis?





Explanation

In pediatric radial head (and especially radial neck) fractures, conservative management is often emphasized due to the significant remodeling potential of the growing bone. Surgical intervention is typically reserved for highly displaced fractures or those with severe mechanical blocks. Radial head replacement or excision is rarely performed in children due to the presence of the open physis and potential for growth disturbance. Aggressive ORIF should be avoided if possible to prevent physeal injury, and long-term antibiotics are irrelevant.

Question 42

A 50-year-old male with a history of recurrent elbow dislocations presents with a comminuted radial head fracture. Which of the following would be an appropriate prophylactic measure to consider against heterotopic ossification (HO)?





Explanation

For high-risk patients (e.g., those with recurrent dislocations, severe comminution, associated head injury, or previous HO) undergoing elbow surgery, prophylactic measures against heterotopic ossification (HO) are often considered. Post-operative radiotherapy (typically a single dose of 700 cGy within 72 hours of surgery) and/or NSAIDs (like indomethacin) are the most evidence-based options to reduce the incidence and severity of HO. Strict bed rest is detrimental. Corticosteroids are not a primary HO prophylaxis. CPM is for motion, not HO prevention specifically. Vitamin D is not relevant to HO prophylaxis.

Question 43

What clinical test helps assess lateral ulnar collateral ligament (LUCL) integrity in the context of an elbow injury suspected of posterolateral rotatory instability?





Explanation

The pivot shift test of the elbow (often performed gravity-assisted or with a specific maneuver to apply valgus and supination moment) is used to assess for posterolateral rotatory instability (PLRI), which is primarily caused by injury to the lateral ulnar collateral ligament (LUCL). Valgus stress tests the MCL, varus tests the LCL complex broadly (including LUCL but less specific for PLRI), milking maneuver tests MCL, and Cozen's test is for lateral epicondylitis.

Question 44

When is radial head replacement generally favored over open reduction internal fixation (ORIF) for radial head fractures?





Explanation

Radial head replacement is generally favored over ORIF for radial head fractures that are highly comminuted and not amenable to stable reconstruction (typically Mason-Johnston Type III or IV), or when there are associated severe instabilities like a terrible triad injury or an Essex-Lopresti lesion. In these cases, replacement helps restore radial length, stability, and provides a buttress against further displacement or dislocation. ORIF is preferred for reconstructible fractures (e.g., Type II, some Type III). Replacement is generally avoided in children and not indicated for Type I or non-displaced fractures.

Question 45

A 60-year-old male undergoes ORIF of a radial head fracture. Two weeks post-op, he develops persistent pain, warmth, redness, and swelling in the elbow, with fever. Which diagnostic test is most appropriate to confirm the suspected complication?





Explanation

The described symptoms (pain, warmth, redness, swelling, fever) are highly suggestive of a post-operative infection. The most appropriate diagnostic test to confirm an intra-articular infection is an elbow arthrocentesis to aspirate synovial fluid for Gram stain, cell count with differential, and bacterial culture. This provides definitive microbiological diagnosis. While imaging (MRI/CT) can show signs of infection, fluid analysis is gold standard. EMG is for nerve issues. Radiographs would only show obvious hardware complications or severe osteomyelitis, not early infection.

Question 46

Which of the following describes the function of the oblique cord?





Explanation

The oblique cord is a fibrous band extending from the ulna to the radius, just distal to the radial tuberosity. It is considered a secondary stabilizer of the forearm, providing some resistance to proximal migration of the radius. While not as strong as the interosseous membrane, it contributes to longitudinal stability. It does not primarily stabilize the DRUJ (TFCC does that), reinforce the anterior capsule, maintain radial head position (annular ligament), or prevent valgus stress (MCL/radial head).

Question 47

What specific type of fracture is typically managed with non-operative treatment consisting of brief immobilization and early range of motion?





Explanation

Mason-Johnston Type I radial head fractures are non-displaced or minimally displaced and typically have no mechanical block to motion. These are managed non-operatively with a brief period of immobilization for comfort, followed by early active range of motion to prevent stiffness. All other options listed typically require surgical intervention due to displacement, mechanical block, or instability.

Question 48

When assessing the healing of a radial head fracture treated with ORIF, what is the primary radiographic sign to look for before escalating rehabilitation?





Explanation

Evidence of bridging callus formation across the fracture site on radiographs is the primary sign of biological healing. This indicates that the fracture is gaining stability and can tolerate increased stress, allowing for escalation of rehabilitation exercises and activity levels. While resolution of swelling and pain are good clinical signs, osseous healing is the key biological indicator. Perfect anatomical alignment is a goal of surgery, not necessarily a sign of healing itself. Full strength comes much later in rehab.

Question 49

Which of the following surgical complications is specifically related to the removal of the radial head?





Explanation

Proximal migration of the radius is a specific complication related to radial head excision. The radial head contributes to longitudinal forearm stability. Its removal without replacement, especially if the interosseous membrane is also compromised, allows the radius to migrate proximally, leading to changes in forearm mechanics, DRUJ incongruity, and often chronic wrist pain and dysfunction. While other complications can occur, proximal migration is characteristic of radial head excision.

Question 50

A patient is scheduled for ORIF of a radial head fracture. Pre-operative assessment reveals a high-riding radial head relative to the ulna on the ipsilateral wrist X-ray. This finding suggests which associated injury?





Explanation

A high-riding radial head (or a positive ulnar variance, relative shortening of the radius) on an ipsilateral wrist X-ray following a radial head fracture is a classic sign of an Essex-Lopresti lesion. This indicates disruption of the interosseous membrane and/or distal radio-ulnar joint, allowing for proximal migration of the radius due to the loss of the radial head's stabilizing effect. This finding is critical for surgical planning as it indicates the need for radial head replacement to restore radial length.

Question 51

What is the primary concern when managing a radial head fracture in an elderly, osteoporotic patient?





Explanation

In elderly, osteoporotic patients, the primary concern when managing a radial head fracture with ORIF is the difficulty in achieving stable fixation with standard implants due to poor bone quality. Osteoporotic bone often cannot hold screws and plates securely, leading to construct failure, particularly in comminuted fractures. This might necessitate a change in strategy towards radial head replacement or even excision, depending on the patient's demand and the fracture pattern. While non-union and arthritis are concerns, fixation stability is paramount.

Question 52

Which of the following statements about radial head prostheses is true?





Explanation

Modular metallic radial head prostheses are crucial for restoring radial length and providing stability, particularly in complex, unreconstructible fractures or those associated with forearm instability (Essex-Lopresti). They prevent proximal migration of the radius and maintain proper forearm mechanics. Silicone implants have fallen out of favor due to wear and osteolysis. Prostheses are not used for Type I fractures. While long-term results can be excellent for appropriate indications, they are not superior to ORIF for all fracture types, especially reconstructible ones. Loosening can occur but is not typically due to aggressive bone ingrowth.

Question 53

What is the most common cause of early post-operative stiffness following radial head fracture fixation?





Explanation

Early post-operative stiffness following radial head fracture fixation is very commonly caused by hardware prominence and impingement. If screws or plates are not properly countersunk or are placed outside the 'safe zone,' they can impinge on the capitellum or ulna during motion, causing pain and restricting range of motion. While infection, nerve injury, and non-union can cause issues, mechanical impingement is a leading cause of early stiffness directly related to fixation.

Question 54

Which muscle group is typically spared in a posterior interosseous nerve (PIN) palsy?





Explanation

The extensor carpi radialis longus (ECRL) is typically spared in a posterior interosseous nerve (PIN) palsy because it is innervated by the radial nerve proximal to the division into superficial radial nerve and PIN. Therefore, patients with PIN palsy can still extend their wrist radially (ECRL action) but will have weakness or paralysis of finger and thumb extension, as well as ulnar wrist extension (ECU) and often weak supination (supinator). The anconeus is also innervated proximally to the PIN split.

Question 55

What is the most crucial step in managing an Essex-Lopresti lesion involving a radial head fracture?





Explanation

The most crucial step in managing an Essex-Lopresti lesion is the restoration of radial length and stabilization of the distal radio-ulnar joint (DRUJ). This is typically achieved with a radial head replacement. Simply excising the radial head would exacerbate the proximal migration and DRUJ instability. Isolated repair of the interosseous membrane is often insufficient without addressing radial length. Sling immobilization and arthrodesis are not appropriate for this severe, unstable injury pattern.

Question 56

Which of the following imaging modalities is considered the gold standard for detailed assessment of ligamentous injuries of the elbow, frequently associated with radial head fractures?





Explanation

MRI (Magnetic Resonance Imaging) is considered the gold standard for detailed assessment of soft tissue structures, including ligaments (e.g., medial collateral ligament, lateral ulnar collateral ligament, annular ligament), tendons, and the interosseous membrane around the elbow. While radiographs and CT are excellent for bony injuries, MRI provides superior visualization of ligamentous tears and capsular disruptions often associated with complex radial head fractures and dislocations.

Question 57

A 40-year-old patient with a Mason-Johnston Type II radial head fracture undergoes ORIF. Post-operatively, they develop chronic elbow pain, stiffness, and crepitus that is unresponsive to therapy. Radiographs show no hardware impingement or loosening. What long-term complication might be suspected?





Explanation

Chronic pain, stiffness, and crepitus following an intra-articular fracture, even after successful ORIF, often indicate the development of post-traumatic osteoarthritis. Despite anatomic reduction, the initial cartilage injury and altered biomechanics can lead to progressive articular degeneration. While CRPS is a possibility for chronic pain, osteoarthritis is a common outcome from articular fractures. Neuroma and carpal tunnel are nerve issues, and DVT is a vascular complication.

Question 58

What is the primary stabilizer preventing valgus stress at the elbow?





Explanation

The anterior bundle of the medial collateral ligament (MCL) is the primary static stabilizer preventing valgus stress at the elbow, particularly from 30 to 120 degrees of flexion. The radial head acts as a secondary valgus stabilizer, providing a bony buttress, especially when the MCL is compromised. The LUCL stabilizes against varus and posterolateral rotatory instability. The annular ligament stabilizes the PRUJ.

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Dr. Mohammed Hutaif
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Prof. Dr. Mohammed Hutaif
Consultant Orthopedic & Spine Surgeon
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