Distal Radius Fractures

Introduction

The distal radius fracture is the most common fracture in adult orthopedic practice, with an annual incidence in Northern Europe approaching 30 per 10,000 person-years and a bimodal age distribution that resembles the pattern of other osteoporotic fractures: a smaller peak in young men from high-energy trauma and a substantial peak in elderly women from low-energy ground-level falls. The injury accounts for approximately 17 percent of all adult fractures treated in emergency departments and 75 percent of all forearm fractures in adults. Its prominence in clinical practice is matched by its prominence in the orthopedic exam syllabus: the eponyms (Colles, Smith, Barton, chauffeur, Frykman), the classifications (Frykman, Fernandez, AO/OTA), and the active debate about the relative merits of operative versus non-operative management for elderly patients all feature prominently. This chapter synthesizes the contemporary management of distal radius fractures, drawing on Rockwood and Green’s Fractures in Adults, AO Principles of Fracture Management, Apley & Solomon’s, Miller’s Review of Orthopaedics, and Dutton’s Orthopaedic Examination.

Surgical Anatomy

The distal radius accounts for approximately 80 percent of the load transmission across the wrist (with the remaining 20 percent through the ulna and the TFCC). The articular surface comprises the scaphoid fossa (the larger lateral facet articulating with the scaphoid), the lunate fossa (the smaller medial facet articulating with the lunate), and the sigmoid notch (the concavity on the medial border of the distal radius that articulates with the ulnar head as the distal radioulnar joint). The normal anatomical relationships that the orthopedic surgeon seeks to restore in reduction and fixation are: radial inclination of approximately 22 degrees (range 15 to 30 degrees) on the AP view, radial height (or radial length) of approximately 12 mm from the tip of the radial styloid to the lateral ulnar articular surface, volar tilt of approximately 11 degrees (range 0 to 22 degrees) on the lateral view, and articular congruity with no step- off or gap. Deviations from these parameters produce predictable functional consequences: loss of radial inclination produces ulnar deviation and weakness; loss of volar tilt (dorsal angulation) produces compensatory wrist extension, mid-carpal instability, and decreased grip strength; loss of radial length produces ulnocarpal impaction; and articular incongruity produces post-traumatic arthritis. The principal soft-tissue stabilizers of the wrist include the volar radioulnar ligaments stabilizing the DRUJ, the dorsal radiotriquetral and dorsal intercarpal ligaments, the scapholunate interosseous ligament (frequently injured in association with high-energy distal radius fractures), and the lunotriquetral ligament. The relevant neurovascular structures include the median nerve in the carpal tunnel (vulnerable to acute carpal tunnel syndrome from the fracture and to delayed compression from callus or malalignment), the superficial branch of the radial nerve (vulnerable

during volar surgical approaches and to compression from external fixator pins), the dorsal cutaneous branch of the ulnar nerve (vulnerable in dorsal approaches), and the radial artery (lying lateral to the FCR tendon and entering the operative field in the standard volar approach).

Eponyms and Patterns

The historic eponymous descriptions remain in widespread use and capture meaningful information about mechanism and configuration. Colles fracture (Abraham Colles, 1814): The classic dorsally displaced extra-articular fracture of the distal radius approximately 2 to 3 cm proximal to the articular surface, produced by a fall on the outstretched hand with the wrist in extension. The deformity has been classically described as the “dinner fork” appearance from the lateral view. The injury is the prototypical low-energy fracture of the osteoporotic elderly woman. Smith fracture (Robert Smith, 1854): The volarly displaced fracture of the distal radius, sometimes called the “reverse Colles,” produced by a fall on the flexed wrist or by direct trauma. The Smith fracture is generally more unstable than the Colles fracture and more often requires operative fixation. Barton fracture (John Rhea Barton, 1838): The intra-articular shear fracture of the distal radius with the volar or dorsal articular fragment displaced together with the carpus, representing a fracture-dislocation pattern. Volar Barton is more common than dorsal; both are unstable and require open reduction and buttress plating of the displaced articular fragment. Chauffeur fracture (Hutchinson fracture): The intra-articular oblique fracture of the radial styloid, classically associated with the historical injury of motorcar drivers from cranking the engine and produced by axial impact through the scaphoid into the radial styloid. The pattern is frequently associated with scapholunate ligament injury and perilunate dislocation in higher-energy mechanisms. Die-punch fracture: An intra-articular fracture in which an isolated lunate facet fragment is depressed into the distal radius by impaction from the lunate, producing an articular step-off. The pattern is functionally important because the depressed lunate facet fragment (“die-punch fragment”) is difficult to elevate by ligamentotaxis alone and frequently requires open reduction.

Classifications

Multiple classification systems have been developed for distal radius fractures, reflecting both the heterogeneity of fracture patterns and the historical pursuit of systems that meaningfully guide treatment. The Frykman classification (1967) divides distal radius fractures by the presence of intra-articular involvement (radiocarpal joint, DRUJ, both, or neither) and the presence of ulnar styloid fracture. The classification has eight types but limited correlation with treatment decisions.

The Fernandez classification (1993) is mechanism-based and organizes fractures into five types: type I bending (Colles, Smith), type II shearing (Barton, chauffeur), type III compression (intra-articular impaction, die-punch), type IV avulsion of carpal ligament insertions (ulnar styloid, radial styloid avulsion), and type V combined/high-energy. The AO/OTA classification (region 23) is the most comprehensive and is increasingly used. Type A is extra-articular (A1 isolated ulna, A2 simple radius, A3 complex radius); Type B is partial articular (B1 sagittal, B2 dorsal Barton, B3 volar Barton); Type C is complete articular (C1 simple articular with simple metaphyseal, C2 simple articular with complex metaphyseal, C3 complex articular and metaphyseal). The Lafontaine criteria (1989) identify fractures at risk for redisplacement after closed reduction: dorsal angulation greater than 20 degrees, dorsal comminution, intra-articular involvement, associated ulnar styloid fracture, and patient age over 60. The presence of three or more criteria predicts a high likelihood of secondary displacement and may inform earlier operative intervention.

Diagnosis

The clinical presentation is dorsal swelling and deformity (“dinner fork” in the typical Colles fracture), pain, and reduced active and passive motion. Neurovascular examination is essential and should specifically document median nerve function (sensation in the radial three and a half fingers, abductor pollicis brevis strength), with serial assessment in the patient with significant initial swelling because acute carpal tunnel syndrome is a recognized complication requiring urgent release. Plain radiographs in two orthogonal views (PA and lateral) are the principal imaging study. The radial inclination, radial height (referenced from the ulna), and volar tilt are measured. The carpal alignment should be assessed for any associated scapholunate dissociation (gap >3 mm or “Terry Thomas sign”) or perilunate dislocation. CT is reserved for the patient with significant intra-articular involvement being considered for operative management; CT defines the number and position of articular fragments and is particularly useful for the die-punch fragment.

Non-Operative Management

The majority of distal radius fractures are treated non-operatively. The technique consists of closed reduction under appropriate anesthesia (typically a hematoma block, supplemented by intravenous regional anesthesia, conscious sedation, or, in selected cases, general anesthesia), followed by cast immobilization in a position that maintains the reduction. The reduction technique varies by fracture pattern. For the typical Colles fracture, traction with hyperextension to disimpact the fracture, followed by palmar flexion and ulnar deviation (“position of the cobbler” in some descriptions), restores the radial length, inclination, and tilt. The reduction is held with a short-arm or long-arm cast in slight palmar flexion and ulnar deviation; the position is later neutralized as healing progresses.

For the Smith fracture, the reverse maneuver (traction with dorsiflexion) is used, with the wrist immobilized in slight extension. The duration of immobilization is typically 4 to 6 weeks, with follow-up radiographs at 1, 2, and 6 weeks to monitor position. Acceptable position after reduction depends on patient factors (functional demand, age, comorbidities) but is generally taken as: dorsal angulation no more than 0 to 10 degrees, radial inclination at least 15 degrees, radial shortening no more than 3 to 5 mm, and articular step-off no more than 2 mm. In the elderly low-demand patient, considerably more deformity is acceptable; in the young active patient, anatomical reduction is desired. The principal concern with non-operative management is secondary loss of reduction, particularly in fractures meeting the Lafontaine criteria. Repeat reduction (remanipulation) is sometimes attempted but typically with disappointing results — once a fracture has redisplaced, anatomy is rarely restored without operative intervention.

Operative Management — Indications and Outcomes

The indications for operative fixation of distal radius fracture have been an active area of investigation. The classical indications were largely anatomical: failed closed reduction, loss of reduction in cast, intra-articular fractures with step-off greater than 2 mm, open fractures, and acute carpal tunnel syndrome. The contemporary indications have expanded to include unstable fractures (Lafontaine criteria) where operative fixation may produce better outcomes than initial non-operative trial with predictable redisplacement. The active controversy concerns the elderly patient with displaced unstable distal radius fracture. Multiple trials, including the WRIST trial (Chung et al., 2020) and several European trials, have demonstrated that in patients over 60 to 65 years with displaced unstable fractures, functional outcomes at one year are broadly similar between operative and non-operative management, despite the operative cohort having better radiographic outcomes. This finding has tempered the enthusiasm for routine volar plate fixation in the elderly that emerged in the 2000s and 2010s. The current practice in many centers has moved toward more selective operative intervention in this age group, with the patient’s functional demands, the severity of malreduction after closed treatment, and the patient’s preferences being the principal determinants. In the younger active patient, anatomical fixation remains the standard.

Operative Techniques

Volar Plating Volar locking plate fixation has been the dominant operative technique since the early 2000s, following the introduction of distal radius-specific locking plates by Orbay and others. The advantages over earlier dorsal plating include lower hardware prominence (avoiding the extensor tendon irritation that was the principal complication of dorsal plating), tendon-friendly contouring, and the ability to achieve a stable construct in osteoporotic bone with the locked screws. The approach is the modified Henry approach — a longitudinal incision over the FCR tendon, opening of the FCR sheath, retraction of the

FCR ulnarly with the median nerve and tendon contents, and release of the pronator quadratus from the radius to expose the volar surface. The fracture is reduced, the plate is positioned at or just proximal to the watershed line (the transverse ridge marking the volar prominence of the distal radius, beyond which the plate produces flexor tendon irritation), and locking screws are placed into the distal fragment. The technical considerations include avoidance of dorsal screw penetration (the dorsal cortex is irregular and screws penetrating the dorsal cortex produce extensor tendon irritation and may rupture the EPL tendon at Lister’s tubercle), use of subchondral screws for support of the articular surface, and anatomical reduction of the lunate facet fragment (the “die-punch” fragment), which the standard volar plate does not directly buttress and may require a separate “lunate facet plate” or volar fragment-specific fixation in selected cases. Complications include flexor pollicis longus rupture (the most feared complication, from the plate or screws being too distal — the EPL rupture is the dorsal equivalent), extensor tendon irritation (from prominent screw tips), median nerve injury (during the volar approach), CRPS (in 2 to 8 percent — see Topic Trauma-8), and hardware-related symptoms that occasionally require plate removal. Dorsal Plating Dorsal plate fixation is reserved for specific indications — primarily the dorsal Barton fracture where the dorsal fragment requires buttressing, and selected fractures with dorsal die-punch fragments. The approach is between the third (EPL) and fourth (extensor digitorum communis) extensor compartments, with the EPL routed dorsal to its sheath at closure. Specialized low-profile dorsal plates have reduced the tendon-related complications that limited the older generation of dorsal plates. K-Wire Fixation Closed reduction with K-wire fixation — the Kapandji intrafocal pinning technique or the simpler transverse K-wire fixation — is a useful alternative for selected fractures, particularly the young patient with simple extra-articular or minimally articular patterns. The Kapandji technique uses K-wires placed through the fracture line dorsally and dorsoradially, with the wires then deflected to act as buttresses against redisplacement, and subsequently advanced into the proximal cortex. Outcomes are generally good for appropriate fracture patterns, with the advantage of minimally invasive technique and easy hardware removal. The DRAFFT trial (Costa et al., 2014, 2020) compared K-wire fixation with volar plate fixation for extra-articular fractures in patients over 50 and found broadly similar functional outcomes at one and five years, with K-wire fixation being substantially less expensive and equally effective in this population. External Fixation External fixation with bridging fixator (pins in the radial shaft and the second metacarpal) was the standard operative technique in the 1980s and 1990s before locking plate technology and has been largely supplanted. It retains a role in the severely comminuted

fracture with extensive bone loss, in the open fracture with significant soft-tissue compromise where temporary stabilization is needed, and in the polytrauma patient requiring damage-control fracture management. Non-bridging external fixation (with the distal pins in the distal radius rather than spanning to the metacarpal) is a more modern variant.

Arthroscopic-Assisted Reduction Wrist arthroscopy allows direct visualization of the articular surface during reduction and has shown utility in selected intra-articular fractures, particularly those with depressed lunate facet fragments. Outcomes are reportedly improved in carefully selected cases, but the technique is technically demanding and adoption has been variable.

Associated Injuries

Distal radius fractures are frequently accompanied by injuries that may be missed if not specifically sought. Ulnar styloid fracture is present in 50 to 60 percent of distal radius fractures; the great majority do not require specific treatment, but base of styloid fractures with associated DRUJ instability may require fixation. TFCC injury is common in higher-energy patterns; the great majority are managed non-operatively but DRUJ instability after radius fixation is an indication for TFCC repair. Scapholunate ligament injury is present in up to 50 percent of high-energy distal radius fractures; recognition by intraoperative arthroscopy or fluoroscopic ligamentous stress views, with appropriate K- wire or open repair when indicated, prevents the chronic scapholunate instability that may follow. Acute carpal tunnel syndrome from acute fracture is a surgical emergency requiring immediate carpal tunnel release in addition to fracture management. Distal radioulnar joint instability after radial fixation requires assessment in all three forearm rotation positions; persistent DRUJ instability requires additional management as discussed for the Galeazzi injury in Topic Trauma-16. Carpal injuries including perilunate dislocations may accompany high-energy distal radius fractures and are addressed in Topic Trauma-18.

Summary and Take-Home Points

The distal radius fracture is the most common adult fracture, with a bimodal age distribution dominated by the low-energy osteoporotic fracture in the elderly woman. The historic eponyms (Colles, Smith, Barton, chauffeur, die-punch) capture meaningful information about mechanism and configuration; the modern Fernandez and AO/OTA classifications provide more systematic frameworks for treatment planning. The treatment of choice for the majority of distal radius fractures remains closed reduction and cast immobilization, with acceptable position parameters (volar tilt, radial inclination, radial length, articular step-off) that vary by patient age and functional demand. The Lafontaine criteria identify fractures at risk for redisplacement and may inform earlier operative intervention.

For operative fixation, volar locking plate fixation has been the dominant technique for the past two decades, with the watershed line, dorsal screw penetration, and FPL tendon rupture being the principal technical considerations. K-wire fixation remains a valuable and cost-effective alternative for appropriate fracture patterns, particularly in older patients with simple extra-articular fractures (DRAFFT trial). External fixation has been largely supplanted but retains a role in severely comminuted patterns and damage-control settings. Arthroscopic-assisted reduction provides direct articular visualization in selected intra-articular fractures. The active controversy in the field concerns the management of the elderly patient with displaced unstable fracture, with multiple trials demonstrating broadly similar functional outcomes between operative and non-operative management at one year. This finding has shifted practice toward more selective operative intervention in this age group, with the younger active patient continuing to receive anatomical fixation as the standard of care. The acute carpal tunnel syndrome from acute fracture, CRPS, and unrecognized scapholunate ligament injury are the principal complications and associated injuries that demand specific attention. The chapter that follows addresses the wrist and hand, including the perilunate injuries and the small-bone fractures of the carpus and metacarpus.