ABOS Part I Orthopedic Surgery Review: Forearm, Wrist & Galeazzi Fracture Management | Part 22200

Correct Answer: B

For Gustilo-Anderson Type II open both bones forearm fractures, immediate definitive internal fixation with plates (Option B) is generally recommended after thorough initial debridement. Type II open fractures typically have moderate soft tissue damage but sufficient coverage for internal fixation. The goal is to achieve stable osteosynthesis, which allows for early soft tissue coverage (if needed) and rehabilitation, minimizing the risk of infection and non-union. Plating provides rigid fixation crucial for adult forearm fractures.

Incorrect Options:

• A. Application of a long arm cast after wound closure: Casting is inadequate for unstable diaphyseal forearm fractures, especially open ones, as it does not provide the rigid fixation required for optimal healing and functional recovery in adults.
• C. Application of an external fixator with delayed definitive fixation: External fixation is typically reserved for higher-grade open fractures (Type IIIB or IIIC) with massive soft tissue loss, gross contamination, or significant bone loss where immediate internal fixation is not feasible or safe. For a Type II, internal fixation is preferred.
• D. Flexible intramedullary nailing of both bones: Flexible intramedullary nailing (FIN) is primarily indicated for pediatric forearm fractures. In adults, IM nailing of both bones often provides insufficient rotational stability and has a higher risk of malunion compared to plating.
• E. Serial debridement and delayed primary closure, followed by casting: While serial debridement might be considered for more contaminated or higher-grade open fractures, for a Type II with minimal contamination, immediate definitive fixation is preferred. Casting after delayed closure is still inadequate for stable fixation.

Correct Answer: C

Dynamic compression plates (DCPs) are specifically designed to create direct axial compression across a fracture site (Option C) as the screws are tightened into their eccentric holes. This compression reduces the fracture gap, increases interfragmentary friction, and promotes primary bone healing, which is the goal for simple diaphyseal fractures in adults. This is a fundamental principle of stable internal fixation for these types of fractures.

Incorrect Options:

• A. Neutralization of shear forces across an oblique fracture: While a plate can neutralize forces, this is typically the role of a neutralization plate, which protects lag screws providing interfragmentary compression in oblique fractures. The primary mechanism of a DCP for a simple fracture is axial compression.
• B. Bridge plating for comminuted segments: Bridge plating is a technique used for comminuted fractures where direct compression is not possible. The plate spans the comminuted zone without screws in the central fragments, allowing for indirect reduction and callus formation (secondary healing). This is not the primary function of a DCP in a simple fracture.
• D. Buttress support to prevent collapse of metaphyseal bone: Buttress plating is used for metaphyseal fractures to prevent collapse under axial load, often seen in articular fractures. This is not the primary role of a DCP in a diaphyseal fracture.
• E. Lag screw fixation for interfragmentary compression: Lag screws provide interfragmentary compression, which is crucial for oblique fractures. While lag screws can be used in conjunction with a plate, the plate itself, when used as a compression plate, provides axial compression across the fracture ends, which is distinct from lag screw function.

Correct Answer: E

The posterior (dorsal) subcutaneous approach to the ulna shaft is generally considered the safest and most direct because the ulna is largely subcutaneous along its posterior border. This approach requires minimal muscle dissection, thereby significantly reducing the risk of injury to major neurovascular structures. The ulnar nerve, radial artery, and radial nerve branches are located more anteriorly or laterally in the forearm, away from the direct path of this approach to the ulna.

Incorrect Options:

• A. Ulnar nerve: The ulnar nerve is located medially and volarly in the forearm, not typically at risk with a direct posterior approach to the ulna shaft.
• B. Posterior interosseous nerve: The posterior interosseous nerve (PIN) is a branch of the radial nerve and is located in the dorsal compartment of the forearm, but it is typically deep and lateral, not directly in the field of a posterior subcutaneous ulnar approach. It is more at risk with dorsal approaches to the radius.
• C. Radial artery: The radial artery is located on the volar-radial aspect of the forearm and is at risk with the Henry (anterior) approach to the radius, not the posterior ulna.
• D. Superficial radial nerve: The superficial radial nerve is also on the radial side of the forearm, deep to the brachioradialis, and is at risk with radial approaches, not the posterior ulna.

Correct Answer: C

For unstable and completely displaced diaphyseal forearm fractures in children where closed reduction fails, flexible intramedullary nailing (FIN) is the treatment of choice (Option C). FIN provides stable fixation, allows for early motion, and preserves the growth plates. In a 6-year-old, the remodeling potential is still significant, but complete displacement and instability after failed closed reduction necessitate surgical stabilization to ensure anatomical alignment and prevent malunion. FIN is minimally invasive and allows for excellent functional outcomes.

Incorrect Options:

• A. Repeat closed reduction under general anesthesia and apply a long arm cast: While a repeat closed reduction under general anesthesia might be attempted, if the fracture is truly unstable and completely displaced, maintaining reduction with casting alone is often difficult and prone to failure, especially after an initial failed attempt. This is not the most appropriate next step for definitive management if stability is a concern.
• B. Open reduction and internal fixation (ORIF) with 3.5mm dynamic compression plates: Plating is generally reserved for older adolescents or specific complex cases in children (e.g., highly comminuted, open fractures, or failed FIN) due to potential issues with growth plate injury, larger dissection, and the need for hardware removal. FIN is preferred in this age group.
• D. Application of an external fixator for temporary stabilization: External fixation is typically reserved for open fractures with significant contamination, highly comminuted fractures with severe soft tissue injury, or situations where internal fixation is contraindicated. It is not the primary definitive treatment for a closed, unstable diaphyseal fracture in a child.
• E. Observation with serial radiographs for remodeling potential: Observation is inappropriate for a completely displaced and unstable fracture after failed reduction in a child, as remodeling potential is limited for rotational or significant angular deformities, and instability will lead to malunion.

Correct Answer: D

The patient's symptoms (severe pain disproportionate to injury, pain with passive stretch of fingers, paresthesias in the median nerve distribution affecting the thumb and index finger, and swelling) are classic signs of acute compartment syndrome. Despite palpable pulses, which are often preserved until late stages, the clinical picture is highly suspicious. The most appropriate immediate diagnostic and management step is to urgently measure forearm compartment pressures (Option D). This is the definitive diagnostic test, and if pressures are elevated above a critical threshold (typically within 30 mmHg of diastolic blood pressure or absolute pressure >30-40 mmHg), emergent fasciotomy is indicated.

Incorrect Options:

• A. Administer additional opioid analgesics and reassess in 2 hours: This is dangerous and can mask the worsening symptoms of compartment syndrome, leading to delayed diagnosis and irreversible tissue damage.
• B. Obtain an immediate CT scan of the forearm to rule out hematoma: A CT scan is not the primary diagnostic tool for compartment syndrome. While a hematoma can contribute to compartment pressure, the definitive diagnosis relies on direct pressure measurements.
• C. Remove the surgical dressing and bivalve the cast/splint: While removing a tight dressing or bivalving a cast/splint is a crucial initial step if external compression is suspected, it is not the most appropriate immediate diagnostic and management step for suspected compartment syndrome in a post-operative setting where internal swelling is the primary concern. Pressure measurement is still required to confirm the diagnosis and guide fasciotomy.
• E. Elevate the limb above heart level and apply ice packs: Elevation can reduce blood flow to the limb, potentially worsening ischemia in a limb with compromised perfusion due as in compartment syndrome. Ice packs are also generally contraindicated as they can cause vasoconstriction and further reduce blood flow. The limb should be kept at heart level.

Correct Answer: D

The described symptoms (painful loss of pronation/supination) and radiographic findings (abnormal bone formation bridging the radius and ulna) are classic for heterotopic ossification leading to synostosis (Option D). Synostosis is the abnormal fusion of the radius and ulna, severely impairing the unique rotational function of the forearm. High-energy trauma with extensive soft tissue injury and prolonged operative time are significant risk factors for its development, as they lead to a robust inflammatory response that can trigger heterotopic bone formation.

Incorrect Options:

• A. Delayed union; patient age: Delayed union would present as persistent pain at the fracture site with radiographic evidence of incomplete healing, not abnormal bone bridging the two bones. While age can influence healing, it's not the primary risk for synostosis.
• B. Deep infection; inadequate antibiotic prophylaxis: Deep infection would typically present with pain, fever, erythema, swelling, and possibly purulent discharge. While infection can lead to bone changes, it doesn't typically cause bone bridging between the radius and ulna in this manner.
• C. Complex Regional Pain Syndrome (CRPS) Type I; prolonged immobilization: CRPS presents with pain, swelling, skin changes (shiny, thin), allodynia, and diffuse osteopenia. While it can cause stiffness, it does not involve abnormal bone bridging between the radius and ulna. Prolonged immobilization is a risk factor for CRPS, but not the primary cause of synostosis.
• E. Hardware failure; inadequate plate length: Hardware failure would involve breakage or loosening of the plate/screws, leading to instability and pain, not bone fusion between the two bones. Inadequate plate length is a risk factor for non-union or refracture, not synostosis.

Correct Answer: C

A CT scan with 3D reconstruction and specific rotational measurements (Option C) is the most accurate and reliable method to quantify rotational malunion of the forearm. Plain radiographs are notoriously unreliable for assessing rotational deformities. CT provides detailed axial images that can be used to measure the relative rotation between the proximal and distal fragments, which is crucial for precise surgical correction.

Incorrect Options:

• A. Clinical estimation of forearm rotation compared to the contralateral side: Clinical assessment is essential for initial evaluation and determining functional impairment, but it is subjective and lacks the precision required for accurate quantification and surgical planning of rotational malunion.
• B. Standard AP and lateral radiographs of the forearm: Plain radiographs are excellent for assessing angulation, shortening, and translation, but they are highly inaccurate for quantifying rotational deformities due to projectional artifacts.
• D. MRI scan of the forearm to assess soft tissue impingement: MRI is superior for evaluating soft tissue structures, ligaments, and cartilage, but it is not the primary modality for precise bone rotational measurements.
• E. Ultrasound assessment of muscle contracture: Ultrasound can assess muscle and tendon integrity or contracture, but it cannot accurately quantify bone rotational malunion.

Correct Answer: C

For a hypertrophic non-union of the ulna shaft with persistent pain and abundant but non-bridging callus, the primary issue is typically inadequate stability at the fracture site. The most appropriate management strategy is revision open reduction, rigid internal fixation with a new plate and screws, and bone grafting (Option C). The bone graft provides osteoinductive and osteoconductive properties to stimulate healing, while the rigid fixation addresses the mechanical instability. A hypertrophic non-union indicates biological activity but insufficient mechanical environment for healing.

Incorrect Options:

• A. Continue with conservative management and physiotherapy, as hypertrophic non-unions often heal spontaneously: While some hypertrophic non-unions might eventually heal, 9 months post-ORIF with persistent symptoms indicates a failed attempt at healing. Continued conservative management is unlikely to succeed without addressing the underlying mechanical issue.
• B. Bone graft stimulation via percutaneous injection: Percutaneous injections (e.g., PRP, bone marrow aspirate) are typically used for delayed unions or atrophic non-unions where biological stimulation is the primary need. For a hypertrophic non-union, the biological response is already present, but mechanical stability is lacking.
• D. Application of an external fixator with bone transport: External fixation with bone transport is a complex technique reserved for infected non-unions with significant bone loss or limb length discrepancy. It is not indicated for a sterile hypertrophic non-union.
• E. Conversion to intramedullary nail with reaming: While intramedullary nailing can be used for some long bone non-unions, it is generally less favored for adult forearm non-unions due to concerns about rotational stability and the difficulty of achieving adequate compression. Plating offers superior rotational control and compression for forearm non-unions.

Correct Answer: D

Refracture through previous screw holes after plate removal is a known complication due to the 'stress riser' effect, where the holes create points of stress concentration in the bone. The most important prophylactic measure is to protect the limb from strenuous activity and heavy lifting for an adequate period (typically 6-12 weeks, Option D) post-removal. This allows the screw holes to remodel and regain sufficient strength, reducing the risk of refracture. Gradual return to activity is key.

Incorrect Options:

• A. Begin immediate, aggressive physiotherapy to restore full range of motion: While early motion is generally desirable, immediate aggressive physiotherapy would place excessive stress on the weakened bone, significantly increasing the risk of refracture.
• B. Re-drill and bone graft all previous screw holes: Re-drilling and bone grafting of screw holes is not a standard or routinely recommended procedure after hardware removal. The bone typically remodels and fills these holes naturally over time.
• C. Maintain strict immobilization in a long arm cast for 6 weeks: Strict immobilization for 6 weeks would lead to significant stiffness and is generally not necessary after hardware removal for a healed fracture. It would also delay functional recovery.
• E. Prescribe bisphosphonates to improve bone density: Bisphosphonates are used for osteoporosis and would not acutely strengthen the bone around screw holes to prevent refracture in this timeframe.

Correct Answer: C

In children, remodeling potential for forearm fractures is influenced by age, proximity to the physis, and the plane of deformity. Volar angulation (Option C) in the sagittal plane generally has superior remodeling potential compared to dorsal angulation, and significantly better than angulation in the coronal plane (radial or ulnar angulation) or rotational deformities. This is due to the inherent growth and remodeling capabilities of bone, which are more effective in correcting sagittal plane deformities, especially when the apex of the deformity is directed away from the joint.

Incorrect Options:

• A. Rotational deformities remodel significantly in children of this age: Rotational deformities remodel poorly at any age, and even small degrees of rotational malalignment can lead to significant functional impairment of pronation and supination.
• B. Angulation in the coronal plane (radial or ulnar) remodels better than in the sagittal plane: This is incorrect. Angulation in the sagittal plane (volar or dorsal) generally remodels better than angulation in the coronal plane.
• D. Remodeling potential is excellent for all types of deformities in a 10-year-old: Remodeling potential decreases with age, and while still present in a 10-year-old, it is not excellent for all types of deformities, particularly rotational and significant coronal plane angulation.
• E. Remodeling potential is minimal for diaphyseal fractures in children over 8 years old: While remodeling potential decreases with age, it is not minimal for diaphyseal fractures in a 10-year-old, especially for sagittal plane angulation. However, it is less than in younger children.

Correct Answer: B

The interosseous membrane (IOM) acts as a crucial passive ligamentous stabilizer (Option B) in the forearm. Its primary biomechanical function is to transfer axial load from the radius to the ulna, particularly during gripping and weight-bearing activities through the wrist. It also provides stability against longitudinal and rotational forces, maintaining the relative positions of the radius and ulna. Disruption of the IOM (e.g., in Essex-Lopresti injuries) leads to severe instability of the forearm and wrist.

Incorrect Options:

• A. It serves as the primary attachment site for the pronator quadratus muscle: While some muscles (e.g., FPL, FDP) originate from the IOM, the pronator quadratus primarily attaches to the distal metaphysis of the radius and ulna. The IOM's primary role is not muscle attachment.
• C. It provides a vascular conduit for the nutrient arteries of the radius and ulna: The nutrient arteries enter the bone directly and are not primarily housed within the IOM as a conduit. The anterior and posterior interosseous arteries run along the membrane, but the membrane itself is not the primary vascular conduit for the bones.
• D. It facilitates smooth gliding between the radius and ulna during pronation and supination: The IOM is a fibrous structure that limits motion rather than facilitating smooth gliding. The articular surfaces of the radial head and distal radioulnar joint, along with the capsule, facilitate gliding.
• E. It prevents distal migration of the radial head: The IOM helps maintain the longitudinal stability of the forearm, which indirectly supports the radial head. However, the annular ligament and the integrity of the proximal radioulnar joint are the primary structures preventing distal migration of the radial head.

Correct Answer: E

The Fernandez classification categorizes distal radius fractures based on the mechanism of injury and fracture morphology. Type I is bending (meta-epiphyseal), Type II is shearing (Barton, Hutchinson), Type III is compression (die-punch), Type IV is avulsion (ligament), and Type V is combined or high-energy fractures with extensive comminution and bone loss. Significant comminution, articular involvement of both fossae, and extension into the diaphysis (often implying severe metaphyseal involvement or bone loss) points strongly towards a high-energy injury, characteristic of a Type V Fernandez fracture.

Correct Answer: D

Instability criteria often guide the decision for surgical fixation following a distal radius fracture. Common indicators of instability include initial dorsal angulation greater than 20 degrees, radial shortening exceeding 3mm, severe metaphyseal comminution, and particularly, intra-articular step-off or gap greater than 1-2mm. While an ulnar styloid fracture is frequently associated with distal radius fractures and may suggest a TFCC injury, its presence alone is not a direct criterion for radial fracture instability or a primary indication for surgical intervention on the radius, assuming other parameters are acceptable. It might influence DRUJ stability, but not necessarily the stability of the radial reduction itself.

Correct Answer: D

The Henry approach for volar plating of the distal radius involves an incision between the Flexor Carpi Radialis (FCR) and the Radial Artery. The FCR tendon is retracted ulnarly, and the radial artery and brachioradialis are retracted radially. The critical step to expose the volar aspect of the distal radius is the subperiosteal elevation and L-shaped release of the Pronator Quadratus muscle from its radial and distal attachments, which is then reflected ulnarly. The median nerve lies more ulnarly, and the FPL tendon is in the deep flexor compartment and typically not the primary muscle reflected for direct radial access.

Correct Answer: C

Difficulty extending the thumb IP joint (interphalangeal joint) is the hallmark sign of Extensor Pollicis Longus (EPL) rupture. EPL rupture is a known complication of distal radius fractures, particularly after dorsal plating, due to attrition over rough bone edges, plate prominence, or direct plate impingement. It can also occur post-closed reduction due to attrition over a dorsal bony prominence or as part of a delayed presentation (e.g., following a Colles' fracture). The Finkelstein's test is for De Quervain's tenosynovitis (APL and EPB), which is not directly related to EPL rupture, hence the assumption of it being a secondary finding.

Correct Answer: C

On a true lateral radiograph of the wrist, the distal articular surface of the radius normally exhibits a volar tilt. The accepted normal range is typically 10 to 15 degrees of volar tilt. A neutral or dorsal tilt is considered abnormal and is a characteristic deformity of a Colles' fracture.

Correct Answer: C

The Triangular Fibrocartilage Complex (TFCC) is the primary static stabilizer of the DRUJ. It is a complex structure comprising the articular disc, dorsal and volar radioulnar ligaments, and the meniscal homologue. While the dorsal and volar radioulnar ligaments within the TFCC are key components, the TFCC as a whole unit provides the most significant static stability. The interosseous membrane provides some longitudinal stability to the forearm, and the Pronator Quadratus offers dynamic stability. The ECU tendon sheath is adjacent but not a primary stabilizer.

Correct Answer: C

While all listed findings represent aspects of malunion, an intra-articular step-off of 3mm is widely considered the most critical predictor of poor long-term outcomes, particularly post-traumatic arthritis, especially in an active younger patient. Even 1-2mm of intra-articular incongruity is often deemed unacceptable. Dorsal tilt >10-15 degrees and radial shortening >2-3mm are also significant, and ulnar positive variance is directly related to radial shortening. However, articular step-off directly compromises joint congruity and leads to accelerated degenerative changes, making it the least acceptable from a functional prognosis standpoint.

Correct Answer: C

Early recognition and aggressive physical and occupational therapy focused on pain-free range of motion, desensitization, and functional use are paramount in managing CRPS. While medications (gabapentin, tricyclic antidepressants) and interventional treatments (sympathetic blocks) have a role, they are often adjuncts. Steroids may be used, but not as the initial most critical step. Spinal cord stimulators are reserved for refractory cases. The key to preventing progression and improving outcomes is early, consistent, and active rehabilitation.

Correct Answer: A

While age and activity level influence treatment decisions, the specific fracture characteristic of a 4mm intra-articular step-off is a very strong, if not absolute, indication for surgical management, regardless of other parameters. Even 1-2mm of articular incongruity is often considered unacceptable, particularly in a younger, active individual, due to the high risk of post-traumatic arthritis. The dorsal tilt and radial shortening mentioned are relatively minor compared to the articular step-off.

Correct Answer: E

Ulnar-sided wrist pain after a distal radius fracture, especially with DRUJ movements, strongly suggests a TFCC injury. The TFCC compression test (axial load with ulnar deviation and rotation) is a specific provocative test for TFCC tears, eliciting pain and sometimes a click. The Scaphoid Shift (Watson) test assesses scapholunate instability. Finkelstein's test is for De Quervain's tenosynovitis. The Grind test is for carpometacarpal arthritis. The Piano Key test assesses DRUJ stability (dorsal/volar translation of the ulnar head).

Correct Answer: C

The Galeazzi fracture-dislocation is classically defined as a fracture of the distal third of the radial diaphysis with concomitant disruption of the distal radioulnar joint (DRUJ), often presenting with dorsal dislocation of the ulna. Monteggia involves an ulnar fracture with radial head dislocation. Colles and Smith are distal radius fractures. Barton is an intra-articular distal radius fracture.

Correct Answer: B

The typical mechanism for a Galeazzi fracture is a fall onto an outstretched hand with the forearm in pronation. This axial load combined with pronation results in an oblique or transverse fracture of the distal radius and often disrupts the DRUJ, as pronation tightens the interosseous membrane, transferring forces to the DRUJ.

Correct Answer: C

Galeazzi fractures in adults are inherently unstable due to the loss of stability provided by the intact radial shaft and disruption of the DRUJ. Non-operative management leads to high rates of malunion and persistent DRUJ instability. Therefore, open reduction and internal fixation (ORIF) of the radial shaft is the standard of care, aiming to restore radial length, rotation, and alignment, followed by careful assessment and, if necessary, stabilization of the DRUJ.

Correct Answer: C

While a radial shaft fracture is central to the diagnosis, the key to recognizing a Galeazzi injury is the associated DRUJ disruption. Radiographically, this often manifests as widening of the DRUJ space on the AP view and/or dorsal (less commonly volar) displacement of the ulna relative to the radius on the lateral view. Comparing to the contralateral wrist can be helpful. Radial head subluxation is associated with Monteggia fractures. Positive ulnar variance can be a normal variant or occur with certain wrist pathologies but is not diagnostic for Galeazzi. Scapholunate dissociation relates to carpal instability.

Correct Answer: C

If, after anatomical reduction and stable fixation of the radial shaft, the DRUJ remains unstable, it is critical to address this. Common causes of persistent instability include interposition of soft tissues (e.g., pronator quadratus, ECU tendon) within the joint, or significant injury to the TFCC or capsule. The most appropriate immediate step is to ensure there are no incarcerated soft tissues preventing reduction and then to stabilize the DRUJ with temporary K-wire fixation, typically with the forearm in supination (or neutral if stable) for 4-6 weeks to allow capsuloligamentous healing. Ulnar head resection or Sauve-Kapandji are salvage procedures for chronic instability or malunion, not primary acute management.

Correct Answer: C

For dorsal DRUJ instability, the forearm is typically immobilized in full supination. In this position, the dorsal DRUJ ligaments are taut, helping to maintain reduction of the ulnar head relative to the sigmoid notch of the radius. Conversely, volar instability (less common in Galeazzi) would require pronation. Pins are usually placed from the dorsal ulna into the radius, avoiding the extensor tendons.

Correct Answer: E

The anterior interosseous nerve (AIN), a branch of the median nerve, is most vulnerable during a volar approach (Henry approach) to the distal radius. It courses on the interosseous membrane and innervates the flexor pollicis longus, pronator quadratus, and the radial half of the flexor digitorum profundus. Injury can occur during dissection, especially when mobilizing the pronator quadratus or stripping muscle from the interosseous membrane. The median nerve trunk itself is deeper but can be retracted. The PIN is associated with the dorsal approach (Thompson approach).

Correct Answer: B

Persistent radial shortening after a Galeazzi fracture leads to a positive ulnar variance, which can cause significant mechanical problems at the DRUJ. This often results in painful impingement and limited range of motion, particularly in pronation and supination, as the altered geometry and DRUJ subluxation restrict normal kinematic coupling between the radius and ulna. Avascular necrosis of the lunate (Kienbock's disease) is associated with negative ulnar variance. Radial nerve palsy is less common as a direct complication of malunion. Flexor tendon rupture and compartment syndrome are not direct long-term consequences of this specific malunion pattern.

Correct Answer: C

The interosseous membrane plays a critical role in forearm stability. Its oblique fibers primarily run from the radius distally and medially to the ulna proximally. This orientation allows it to transmit axial loads from the hand via the radius to the ulna, and also resist longitudinal displacement and provide stability against proximal migration of the radius relative to the ulna, especially during pronation. Its disruption, or altered tension due to radial shortening, significantly impacts DRUJ stability.

Correct Answer: B

The Brachioradialis inserts into the lateral side of the distal radius and its pull can contribute to proximal displacement and shortening of the radial fracture fragment. The Pronator Quadratus originates from the distal ulna and inserts onto the distal radius, acting as a pronator and a key stabilizer of the DRUJ. Its muscle belly can be lacerated by the fracture or complicate exposure during a volar approach.

Radius fractures located within 7.5 cm of the articular surface have a 55% rate of DRUJ instability, compared to only 6% for more proximal fractures. This proximity defines the classic type I Galeazzi fracture.

If the DRUJ is reducible and stable in a specific position (typically full supination) following rigid fixation of the radius, the standard of care is to immobilize the forearm in that stable position for 4 to 6 weeks. Transarticular pinning or open TFCC repair is reserved for DRUJ instability that cannot be stabilized by positioning alone.

The Thompson approach accesses the radius dorsally through the internervous plane between the extensor carpi radialis brevis (supplied by the radial nerve) and the extensor digitorum communis (supplied by the posterior interosseous nerve).

Radial head excision is contraindicated in Essex-Lopresti injuries. Removal of the radial head eliminates the primary proximal restraint to longitudinal migration, leading to catastrophic proximal migration of the radius, positive ulnar variance, and severe wrist pain.

Indications for operative management of isolated ulnar shaft fractures include displacement greater than 50%, angulation greater than 10 degrees, or fractures involving the proximal third. These factors significantly increase the risk of nonunion and poor functional outcomes.

The radial bow is critical for the normal biomechanics of forearm rotation. Failure to accurately restore the magnitude and location of the anatomic radial bow directly restricts pronation and supination.

The distal portion of the Henry approach utilizes the internervous plane between the brachioradialis, which is innervated by the radial nerve, and the flexor carpi radialis, which is innervated by the median nerve.

Radioulnar synostosis is a devastating complication that limits forearm rotation. Risk factors are mitigated by using separate incisions for the radius and ulna, minimizing dissection in the interosseous space, and avoiding bone grafting between the two bones.

Clinical signs of DRUJ instability, defining a Galeazzi fracture, include dorsal or volar prominence of the ulnar head, increased ballotability (piano key sign), and localized pain or swelling precisely at the DRUJ.

The functional longitudinal axis of forearm rotation passes obliquely from the center of the radial head proximally to the fovea at the base of the ulnar styloid distally.

AO principles dictate that rigid plate osteosynthesis of forearm diaphyseal fractures requires a minimum of 3 bicortical screws, achieving 6 cortices of purchase, on each side of the fracture to ensure adequate biomechanical stability.

In the distal Henry approach, the radial artery lies medial to the brachioradialis. It must be carefully mobilized and retracted radially, along with the brachioradialis tendon, to expose the pronator quadratus and distal radius.

Delayed EPL rupture following non-displaced distal radius fractures is primarily attributed to ischemia. The intact extensor retinaculum prevents hematoma expansion, increasing pressure on the EPL in its watershed vascular zone as it curves around Lister's tubercle.

The ECU tendon is the most common block to DRUJ reduction in Galeazzi fracture-dislocations. It can become incarcerated in the joint, necessitating open reduction.

The pronator quadratus pulls the distal radius fragment proximally and into pronation. The brachioradialis also contributes to proximal migration (shortening) but does not primarily cause the pronation deformity.

The Thompson approach utilizes the internervous plane between the extensor carpi radialis brevis (radial nerve) and the extensor digitorum communis (posterior interosseous nerve).

When exposing the proximal radius via the Henry approach, the forearm must be supinated. This rotates the radius and moves the supinator muscle and the enclosed posterior interosseous nerve (PIN) laterally, protecting it from injury.

Bridge plating provides relative stability, which stimulates callus formation and leads to secondary bone healing. Absolute stability, which leads to primary bone healing without callus, is achieved through interfragmentary compression.

Isolated ulnar shaft fractures with less than 50% displacement and less than 10 degrees of angulation are stable. They are best treated non-operatively with a functional brace and early range of motion.

If the DRUJ is stable in supination after radius fixation, transfixation pinning is not necessary. Immobilization in a long-arm splint or cast in supination (the position of stability) for 4 to 6 weeks is the appropriate management.

In an Essex-Lopresti injury (interosseous membrane tear with DRUJ disruption), radial head excision removes the proximal block to radius migration. This leads to severe ulnar positive variance and chronic wrist pain.

A single incision to approach both the radius and ulna significantly increases the risk of radioulnar synostosis (cross-union). Standard practice utilizes separate volar (Henry) and dorsal/subcutaneous approaches.

Fractures of the radius within 7.5 cm of the articular surface have a significantly higher rate of DRUJ instability (over 50%) compared to more proximal fractures. This proximity disrupts the interosseous membrane's stabilizing fibers near the joint.

The proximal internervous plane for the Henry approach lies between the brachioradialis (innervated by the radial nerve) and the pronator teres (innervated by the median nerve). Distally, the plane transitions between the brachioradialis and the flexor carpi radialis.

The extensor carpi ulnaris (ECU) tendon is the most common structure to become interposed and block reduction of the DRUJ in a Galeazzi fracture-dislocation. Open reduction and extraction of the tendon from the joint is required.

In children under 9 years old, acceptable alignment for both-bone forearm fractures includes up to 15 degrees of angulation and complete displacement, provided it is bayonet apposed. The tremendous remodeling potential in this age group corrects the deformity.

The deep volar compartment, containing the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL), is the most frequently and severely affected in forearm compartment syndrome. Early decompression is vital to prevent Volkmann ischemic contracture.

A volar Barton fracture involves a shear fracture of the volar articular rim. The volar plate acts primarily as a buttress plate to counteract the shearing forces and prevent volar subluxation of the carpus.

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating caused by plate prominence distal to the watershed line. The prominent hardware causes attritional wear of the tendon over time.

Using a single incision to approach both the radius and ulna significantly increases the risk of cross-union (radioulnar synostosis) and is generally contraindicated. Separate dorsal and volar incisions are standard to preserve tissue planes.

The Thompson approach utilizes the internervous plane between the extensor carpi radialis brevis (radial nerve) and the extensor digitorum communis (posterior interosseous nerve). It allows exposure of the proximal and middle thirds of the radius.

If the DRUJ is unstable in neutral but stable in supination following radial fixation in a Galeazzi fracture, the standard treatment is immobilization in a long-arm splint or cast in full supination for 4-6 weeks. K-wire fixation is reserved for cases unstable in all positions.

Radial shortening leads to a relative positive ulnar variance, which significantly increases load transmission across the ulnocarpal joint. This predisposes the patient to ulnar impaction syndrome and degenerative tears of the TFCC.

Current AO principles recommend a minimum of 6 cortices (typically three bicortical screws) of fixation on both sides of a diaphyseal forearm fracture. This achieves stable fixation and promotes primary bone healing while allowing early range of motion.

A Bado Type I Monteggia fracture is characterized by an anterior dislocation of the radial head with an associated fracture of the ulnar diaphysis. It is the most common type, especially in the pediatric population.

Indications for operative fixation of isolated ulnar shaft fractures include displacement greater than 50%, angulation greater than 10 degrees, or proximal third involvement. Fractures falling below these thresholds can be treated successfully with functional bracing.

A dorsal spanning plate utilizes the principle of ligamentotaxis to maintain length and alignment in highly comminuted fractures. It is secured to the diaphysis of the radius proximally and the third metacarpal distally, bypassing the carpus.

Extensor pollicis longus (EPL) rupture after non-displaced distal radius fractures is classically attributed to localized ischemia. The tendon becomes compressed within the tight third extensor compartment due to fracture hematoma and swelling.

The posterior interosseous nerve (PIN) typically exits the distal border of the supinator muscle approximately 6 to 8 cm distal to the radiocapitellar joint. Surgeons must protect it during extensile dorsal exposures of the proximal radius.

In a chronic Essex-Lopresti lesion with established proximal radial migration, radial head arthroplasty alone is insufficient due to soft tissue contracture. A combined procedure, typically radial head arthroplasty with an ulnar shortening osteotomy, is required to level the DRUJ and restore stability.

The brachioradialis inserts on the radial styloid and acts as the primary deforming force causing proximal migration and radial shortening in Galeazzi fractures. The pronator quadratus typically pulls the distal fragment volarly and ulnarly.

Restoration of the maximum radial bow magnitude is critical for recovering the full arc of forearm pronation and supination. A loss of the radial bow greater than 10% significantly restricts rotational motion, particularly pronation.

If the DRUJ remains irreducible or grossly unstable in all positions following rigid fixation of the radius, open exploration is required. The extensor carpi ulnaris (ECU) tendon is a classic anatomic block to DRUJ reduction in Galeazzi fractures.

In children under 9 years of age, remodeling potential is high. Acceptable parameters for midshaft both-bone forearm fractures include up to 15 degrees of angulation, 45 degrees of malrotation, and 100% displacement (bayonet apposition).

The volar compartment is the most commonly affected compartment in forearm compartment syndrome. It contains the flexor digitorum profundus and superficialis, which explains the classic sign of severe pain with passive digit extension.

In pediatric patients, the ligaments of the DRUJ are often stronger than the open growth plates. Therefore, a Galeazzi equivalent fracture involves a distal radius fracture combined with a distal ulnar physeal separation rather than true DRUJ ligamentous disruption.

The Thompson approach utilizes the internervous plane between the extensor carpi radialis brevis (supplied by the radial nerve) and the extensor digitorum communis (supplied by the posterior interosseous nerve).

If the DRUJ is reducible and stable in full supination following rigid fixation of the radius, non-operative management of the DRUJ is appropriate. A long-arm cast or splint in supination allows the volar radioulnar ligaments and TFCC to heal.

Bridge plating preserves the soft tissue envelope and blood supply of comminuted fracture segments by providing relative stability. This biomechanical environment stimulates secondary bone healing through the formation of a fracture callus.