Bennett Fracture

Bennett fracture
Bennett fracture on x-ray
Classification and external resources
Specialty	emergency medicine
ICD-10	S62.2
ICD-9-CM	815.x1
eMedicine	orthoped/19

Bennett fracture is a fracture of the base of the first metacarpal bone which extends into the carpometacarpal (CMC) joint.^[1] This intra-articular fracture is the most common type of fracture of the thumb, and is nearly always accompanied by some degree of subluxation or frank dislocation of the carpometacarpal joint.

Nomenclature

The Bennett fracture is named after Edward Hallaran Bennett, Professor of Surgery (1837–1907) at Trinity College of the University of Dublin, who described it in 1882. Bennett said his fracture "passed obliquely across the base of the bone, detaching the greater part of the articular surface, and "the separated fragment was very large and the deformity that resulted there-from seemed more a dorsal subluxation of the first metacarpal".^[2]

Mechanism of injury

The Bennett fracture is an oblique intraarticular metacarpal fracture dislocation, caused by an axial force directed against the partially flexed metacarpal. This type of compression along the metacarpal bone is often sustained when a person punches a hard object, such as the skull or tibia of an opponent, or a wall. It can also occur as a result of a fall onto the thumb. This is a common injury sustained from bike falls, as the thumb is generally extended while around the handle bars. It is also a common injury in car crashes, especially into fixed objects, from the driver holding the steering wheel during impact. The hand moves forward, while the steering wheel rim hyperextends the thumb.

Significance and complicating factors

Many important activities of daily life are dependent on the ability to grasp, pinch, and oppose the thumb. In fact, thumb function constitutes about 50% of overall hand function. These abilities are in turn dependent on an intact and functional thumb CMC joint. The CMC joint of the thumb allows a wide range of motion while maintaining stability for grasp and pinch.

With this in mind, failure to properly recognize and treat the Bennett fracture will not only result in an unstable, painful, arthritic CMC joint with diminished range of motion: it will also result in a hand with greatly diminished overall function.

In the case of the Bennett fracture, the proximal metacarpal fragment remains attached to the anterior oblique ligament, which in turn is attached to the tubercle of the trapezium bone of the CMC joint. This ligamentous attachment ensures that the proximal fragment remains in its correct anatomical position.

The distal fragment of the first metacarpal bone possesses the majority of the articular surface of the first CMC joint. Unlike the proximal fracture fragment, strong ligaments and muscle tendons of the hand tend to pull this fragment out of its correct anatomical position.

Specifically:

tension from the abductor pollicis longus muscle (APL) subluxates the fragment in a dorsal, radial, and proximal direction
tension from the APL rotates the fragment into supination
tension from the adductor pollicis muscle (ADP) displaces the metacarpal head into the palm

Tension from the APL and ADP muscles frequently leads to displacement of the fracture fragments, even in cases where the fracture fragments are initially in their proper anatomic position. Because of the aforementioned biomechanical features, Bennett fractures nearly always require some form of intervention to ensure healing in the correct anatomical position and restoration of proper function of the thumb CMC joint.

Controversy

Some authors have recently made an assertion against popular belief that the APL tendon is not a deforming force on the Bennett fracture.^[3]

Symptoms and signs

Symptoms of Bennett fracture are instability of the CMC joint of the thumb, accompanied by pain and weakness of the pinch grasp. Characteristic signs include pain, swelling, and ecchymosis around the base of the thumb and thenar eminence, and especially over the CMC joint of the thumb. Physical examination demonstrates instability of the CMC joint of the thumb. The patient will often manifest a weakened ability to grasp objects or perform such tasks as tying shoes and tearing a piece of paper. Other complaints include intense pain experienced upon catching the thumb on an object, such as when reaching into a pants pocket.

Treatment

Though these fractures commonly appear quite subtle or even inconsequential on radiographs, they can result in severe long-term dysfunction of the hand if left untreated. In his original description of this type of fracture in 1882, Bennett stressed the need for early diagnosis and treatment in order to prevent loss of function of the thumb CMC joint, which is critical to the overall function of the hand.^[2]

In the most minor cases of Bennett fracture, there may be only small avulsion fractures, relatively little joint instability, and minimal subluxation of the CMC joint (less than 1 mm). In such cases, closed reduction followed by immobilization in a thumb spica cast and serial radiography may be all that is required for effective treatment.^[4]

For Bennett fractures where there is between 1 mm and 3 mm of displacement at the trapeziometacarpal joint, closed reduction and percutaneous pin fixation (CRPP) with Kirschner wires is often sufficient to ensure a satisfactory functional outcome. The wires are not employed to connect the two fracture fragments together, but rather to secure the first or second metacarpal to the trapezium.

For Bennett fractures where there is more than 3 mm of displacement at the trapeziometacarpal joint, open reduction and internal fixation (ORIF) is typically recommended.

Regardless of which approach is employed (nonsurgical, CRPP, or ORIF), immobilization in a cast or thumb spica splint is required for four to six weeks.

Prognosis

If intraarticular trapeziometacarpal fractures (such as the Bennett or Rolando fractures) are allowed to heal in a displaced position, significant post-traumatic osteoarthritis of the base of the thumb is virtually assured.^[5] Some form of surgical treatment (typically either a CRPP or an ORIF) is nearly always recommended to ensure a satisfactory outcome for these fractures, if there is significant displacement.

The long-term outcome after surgical treatment appears to be similar, whether the CRPP or the ORIF approach is used. Specifically, the overall strength of the affected hand is typically diminished, and post-traumatic osteoarthritis tends to develop in almost all cases. The degree of weakness and the severity of osteoarthritis does however appear to correlate with the quality of reduction of the fracture. Therefore, the goal of treatment of Bennett fracture should be to achieve the most precise reduction possible, whether by the CRPP or the ORIF approach.^[6]

External links

References

↑ Bennett fracture-subluxation at GPnotebook
1 2 Bennett EH. Fractures of the Metacarpal Bones. Dublin Med Sci J. 1882;73:72-75.
↑ Edmunds, JO (Aug 2006). "Traumatic dislocations and instability of the trapeziometacarpal joint of the thumb." (PDF). Hand clinics 22 (3): 365–92. doi:10.1016/j.hcl.2006.05.001. PMID 16843802.
↑ Soyer, AD (Nov–Dec 1999). "Fractures of the base of the first metacarpal: current treatment options.". The Journal of the American Academy of Orthopaedic Surgeons 7 (6): 403–12. PMID 11505928.
↑ Foster, RJ; Hastings H, 2nd (January 1987). "Treatment of Bennett, Rolando, and vertical intraarticular trapezial fractures.". Clinical orthopaedics and related research (214): 121–9. doi:10.1097/00003086-198701000-00018. PMID 3791733.
↑ Timmenga, EJ; Blokhuis, TJ; Maas, M; Raaijmakers, EL (June 1994). "Long-term evaluation of Bennett's fracture. A comparison between open and closed reduction.". Journal of hand surgery (Edinburgh, Scotland) 19 (3): 373–7. doi:10.1016/0266-7681(94)90093-0. PMID 8077832.

Fractures and cartilage injuries (Sx2, 800–829)

General

Humerus fracture:	Supracondylar Holstein–Lewis fracture

Forearm fracture:	Ulnar fracture Monteggia fracture Hume fracture Radius fracture/Distal radius Galeazzi Colles' Smith's Barton's Essex-Lopresti fracture

Hand fracture

Pelvic fracture

Leg

Tibia fracture:	Bumper fracture Segond fracture Gosselin fracture Toddler's fracture Pilon fracture Plafond fracture Tillaux fracture

Fibular fracture:	Maisonneuve fracture Le Fort fracture of ankle Bosworth fracture

Combined tibia and fibula fracture:	Trimalleolar fracture Bimalleolar fracture Pott's fracture

Crus fracture:	Patella fracture

Femoral fracture:	Hip fracture

Foot fracture

Orthopaedic eponyms

Medical eponyms

Fractures	Bankart's fracture Barton's fracture Bennett's fracture Bosworth fracture Chance fracture Chopart's fracture-dislocation Colles' fracture Dupuytren's fracture Duverney fracture Essex-Lopresti fracture Galeazzi fracture Gosselin fracture Holstein–Lewis fracture Holdsworth fracture Hutchinson's fracture Hoffa fracture Hume fracture Jefferson fracture Jones fracture Lisfranc fracture Maisonneuve fracture Malgaigne's fracture Monteggia fracture Moore's fracture Pipkin fracture-dislocation Plafond fracture Pott's fracture Rolando fracture Segond fracture Shepherd's fracture Smith's fracture Stieda fracture Tillaux-Chaput avulsion fracture Wagstaffe-Le Fort avulsion fracture Volkmann avulsion fracture

Classifications	Bado classification Danis–Weber classification Denis classification Evans-Jensen classification Ficat classification Frykman classification Garden classification Gartland classification Gruen zone Gustilo open fracture classification Haruguchi classification Hawkin's classification Herbert classification Herscovici classification Ideberg classification Jupiter and Mehne classification Lauge-Hansen classification Le Fort fracture of skull Loder classification Mayfield classification Milch classification Neer classification Pipkin classification Pauwel's classification Riseborough and Radin classification Ruedi-Allgower classification Salter–Harris fracture Schatzker classification of tibia plateau fractures Tile classification Schatzker classification of olecranon fractures Sanders classification Seddon classification Seinsheimer classification Schenck classification Teisen classification Tscherne classification Thompson and Epstein classification Vancouver classification Wassel classification Winquist and Hansen classification Young-Burgess classification

Procedures	Akin osteotomy Bankart repair Broström procedure Brunelli procedure Cotrel–Dubousset instrumentation Cunningham Shoulder Reduction Darrach's procedure Darrah procedure Evans technique Girdlestone's Procedure Keller procedure Kocher manoeuvre Krukenberg procedure Latarjet procedure Mumford procedure Ponseti method Swanson's Arthroplasty Tommy John surgery Weil's Osteotomy Weaver–Dunn procedure Zadek's procedure

Anatomy	Gerdy's tubercle Guyon's Canal Harrison's groove Haversian canal Humphrey's ligament Lisfranc joint Lisfranc ligament Lister's tubercle Martin-Gruber Anastomosis Schmorl's nodes Volkmann's canals

CPRs	Harris Hip Score Kocher criteria Mirel's Score Rowe Score

Clinical signs	Andersson lesion Baastrup's sign Bouchard's nodes Boutonniere deformity Coopernail's sign Codman triangle Destot's sign Frankel's sign Heberden's node Kanavel's sign Larrey's sign Trendelenburg gait

Clinical examination	Allis test Apley grind test Apley scratch test Barlow's maneuver Clarke's test Cozen's test Cotton test Durkan's test Finkelstein's test Froment's sign Jobe's test Kapandji score Gaenslen's test Galeazzi test Gerber's test Hawkins–Kennedy test Hubscher's maneuver Lachman test Lasègue's sign McMurray test Mulder's sign Neer impingement sign O'Brien's test Ober's test Ortolani test Patrick's test Phalen maneuver Simmonds' test Schober's test Speed's test Thomas test Thompson test Tinel sign Trendelenburg's sign Yergason's test Waddell's signs Watson's test Wilson test

Congenital conditions	Albers-Schonberg disease Albright's hereditary osteodystrophy Antley–Bixler syndrome Apert syndrome Beals syndrome Bechterew's Bruck syndrome Camurati–Engelmann disease Catel–Manzke syndrome Cole carpenter syndrome Conradi–Hünermann syndrome Currarino syndrome Ehlers–Danlos syndrome Eiken syndrome Ellis–van Creveld syndrome Erlenmeyer flask deformity Fairbanks disease Hajdu–Cheney syndrome Jansen's metaphyseal chondrodysplasia Kashin–Beck disease Klippel–Feil syndrome Klippel–Trénaunay–Weber syndrome Kniest dysplasia Lobstein syndrome Madelung's deformity Maffucci syndrome Marfan syndrome Marie-Strümpell disease Marshall syndrome Marshall–Smith syndrome McCune–Albright syndrome Melnick–Needles syndrome Morton's toe Ollier disease Rett syndrome Rubinstein–Taybi syndrome Scheuermann's disease Schwartz–Jampel syndrome Silver–Russell syndrome Teunissen–Cremers syndrome Trevor disease Wiedemann syndrome

Acquired conditions	Baker's cyst Bankart lesion Barré–Liéou syndrome Blount's disease Brodie abscess Chandler's disease De Quervain syndrome Dupuytren's contracture Ewing's sarcoma Freiberg disease Garre's sclerosing osteomyelitis Gorham's disease Haglund's deformity Hill–Sachs lesion Iselin's disease Kashin–Beck disease Kienbock's disease Köhler disease Legg–Calvé–Perthes syndrome Morton's neuroma O'Donoghue's triad Osgood–Schlatter disease Paget's disease of bone Panner disease Perthes Lesion Preiser disease Sever's disease Stener lesion Sudeck's atrophy Tietze syndrome Volkmann's contracture

Orthopedic implants	Austin Moore prosthesis Baksi's prosthesis Charnley prosthesis Denis Browne bar Ender's nail Grosse-Kempf nail Harrington rod Herbert screw Kirschner wire Kuntscher nail Moore's pin Neer's prosthesis Rush nail Schanz screw Seidel nail Smith Peterson nail Steinmann pin Swanson prosthesis Talwalkar nail Thompson prosthesis

Orthopaedic instruments	Bryant's traction Charnley Retractor Darrach elevator Faraboeuf forceps Gigli saw Hohmann retractor Ilizarov apparatus Inge retractor Jungbluth forceps Matta forceps Taylor Spatial Frame Thomas splint Verbrugge forceps Volkmann retractor Weber forceps

Surgical approaches	Hardinge lateral approach to the hip Moore or Southern posterior approach to the hip Smith-Petersen anterior approach to the hip Watson-Jones anterolateral approach to the hip

Radiographic signs	Baumann's angle Blumensaat's line Bohler's angle Cobb angle Fairbank's changes Gilula's Lines Harris lines Hilgenreiner's line Kellgren-Lawrence grading scale Klein's line Loosers zone Pauwel's angle Perkin's line Shenton's Line Southwick angle Thurstan Holland sign Trethowan's sign Terry-Thomas sign

Radiographic projections	Judet view Broden's view

Principles	Wolff's law Hueter-Volkmann law Charley's principles of three-point fixation

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