Bennett's fracture: Difference between revisions

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== Definition/Description  ==
== Definition/Description  ==


<br>A Bennett fracture, also known as a Bennett fracture-dislocation, is an intra-articular fracture of the base of the first&nbsp;[[Metacarpal Fractures|metacarpal]] which leads to dislocation of the first carpometacarpal joint (CMCJ). The [[fracture]]&nbsp;involves the joint between the first metacarpal and the proximal carpal bone, the&nbsp;trapezium. The fracture is unstable and has an inadequate reduction/fixation which&nbsp;leads to long term consequences such as [[osteoarthritis]], weakness and / or loss of function.<ref name=":0">C. Brownlie. Bennett Fracture Dislocation: Review and Management; Australian&nbsp;Family Physician vol 40, No. 6, June 2011</ref><ref>Physioroom.com Bennett’s Fracture. http://www.physioroom.com/injuries/hand_and_wrist/bennetts_fracture_full.php<nowiki/>(Accessed 5/05/2013)</ref>  
<br>A Bennett fracture is a fracture of the base of the thumb resulting from forced abduction of the first metacarpal. It is defined as an intra-articular two-part fracture of the base of the first metacarpal bone.<ref name=":1">Radiopedia [https://radiopaedia.org/articles/bennett-fracture Bennett Fracture] Available from:https://radiopaedia.org/articles/bennett-fracture (last accessed 21.3.2020)</ref>


<br>
Despite a relatively simple appearance on radiographs, Bennett fractures are considered unstable.


== Clinically Relevant Anatomy  ==
In evaluating and treating these fractures positioning the patient with thumb extension (hitchhikers position) should be avoided as this will cause further fracture displacement.


<br>The first CMCJ is unique, it has only an articulation between the&nbsp;trapezium and the base of the first metacarpal. The articulation is saddle-shaped&nbsp;which allows greater motion. <ref name=":0" /> The ligaments in&nbsp;this joint are the anterior (volar) and posterior oblique ligaments, the anterior and&nbsp;posterior intermetacarpal ligaments, and the dorsal radial ligament. The anterior&nbsp;oblique ligament is the most important for stability in the carpo-metacarpal joint.<ref>Mark E Baratz, MD; Chief editor: Harris Gellman, Bennett Fracture, Medscap&nbsp;reference http://emedicine.medscape.com/article/1238036-overview#a05<nowiki/>(Accessed&nbsp;5/05/2013)</ref><br>  
If there is a good alignment of the fracture fragments at postsurgical fixation, clinical outcomes are generally good.<ref name=":2">Carter KR, Nallamothu SV. [https://www.ncbi.nlm.nih.gov/books/NBK500035/ Bennett Fracture]. InStatPearls [Internet] 2019 May 18. StatPearls Publishing. Available from:https://www.ncbi.nlm.nih.gov/books/NBK500035/ (last accessed 21.3.2020)</ref>
 
=== Clinically Relevant Anatomy and Pathophysiology ===
<br>The first CMCJ is unique, it has only an articulation between the&nbsp;trapezium and the base of the first metacarpal. The articulation is saddle-shaped&nbsp;which allows greater motion. <ref name=":0">C. Brownlie. Bennett Fracture Dislocation: Review and Management; Australian&nbsp;Family Physician vol 40, No. 6, June 2011</ref> The ligaments in&nbsp;this joint are the anterior (volar) and posterior oblique ligaments, the anterior and&nbsp;posterior intermetacarpal ligaments, and the dorsal radial ligament. The anterior&nbsp;oblique ligament is the most important for stability in the carpo-metacarpal joint.<ref>Mark E Baratz, MD; Chief editor: Harris Gellman, Bennett Fracture, Medscap&nbsp;reference http://emedicine.medscape.com/article/1238036-overview#a05<nowiki/>(Accessed&nbsp;5/05/2013)</ref>
 
The fracture pattern is distinct. The base of the first metacarpal is fractured with intraarticular extension due to the palmar ulnar fragment of the first metacarpal held in place by its ligamentous attachment to the trapezium (known as the anterior oblique ligament) during the axial loading with the rest of the metacarpal moving in the opposite direction and the main fracture line occurring along this point of weakness. Due to this fracture, the first metacarpal shaft subluxes dorsally, proximally, and radially due to the pull of the abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and the adductor pollicus brevis, which remain attached to the fracture fragment.<ref name=":2" /><br>  


== Differential Diagnosis  ==
== Differential Diagnosis  ==
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== Medical Management    ==
== Medical Management    ==


<br>Bennett fractures have several options of management. Each treatment has it’s&nbsp;advantages and disadvantages.<ref name=":0" />
Non-operative treatment in a thumb spica cast for 3-4 weeks can be considered in stable, non-displaced fractures.
 
<sup></sup><br>''Type I - Closed Reduction''
 
<br>The first type of management is closed reduction and plaster casting. This is a non-invasive procedure and remains the first option if possible.The major issue in closed&nbsp;reduction is to obtain and maintain adequate fracture reduction to allow healing in an&nbsp;anatomical position. Consequences of an inaccurate reposition are pain and grip&nbsp;weakness in short term and osteoarthritis of the first metacarpal joint in long term.&nbsp;Hence it is recommended to let these fractures be treated by specialist hand&nbsp;surgeons.<br>All the variant methods of closed reduction involve traction on the thumb to pull&nbsp;metacarpal distally with concurrent pressure pushing the metacarpal base medially to&nbsp;return it to anatomical position.&nbsp;Closed reduction is performed under adequate analgesia/sedation follow by plaster&nbsp;cast immobilization for ±6 weeks. A cast with the thumb in a moderate adduction and&nbsp;opposition is most effective by reducing the fracture fragments.<ref>CULLEN J.P. Et al; Simulated Bennett Fracture Treated With Closed Reduction and&nbsp;Percutaneous Pinning; The journal of Bone and Joint Surgery, 1997</ref>
 
<sup></sup><br>''Type II - K-wires''
 
<br>A second method of reduction involves reduction of the fracture followed by&nbsp;percutaneous insertion of a Kirschner wire through the base of the metacarpal across&nbsp;the joint and into the trapezium to hold the reduction in place. The wire remains in&nbsp;place for about 4 weeks after which a rehabilitation program is started.<ref name=":0" />


<sup></sup><br>''Type III - Open Reduction''
Operative treatment is recommended for unstable fracture patterns and intra-articular displacement of >1 mm. While open reduction and internal fixation with a screw or K-wire are both common practice, screws are often preferred as K-wires must be removed after union.


<br>This last treatment is necessary when there is a significant displacement (&gt;3mm).<ref>Dr MAULIK S. Et al.; “Bennett fracture dislocation”, Radiopaedia, 2012.&nbsp;http://radiopaedia.org/articles/bennett-fracture-dislocation<nowiki/>(Accessed 5/05/2013)</ref>Type III involves an open reduction, which involves opening up the fracture and&nbsp;reduction under direct vision followed by insertion of either Kirschner wires (Fig1) or&nbsp;lag screws in order to hold the reduction in place. Like the second type of&nbsp;management, after the reduction there is an immobilization period of 4 weeks.<br>This type is preferable where there is a large proximal fragment and that ORIF should&nbsp;be used where the fracture is irreducible or a Kirschner wire is unable to be passed&nbsp;across the fracture.<ref>Zhang X. Et al.; Treatment of a Bennett Fracture Using Tension Band Wiring, Journal&nbsp;of Hand Surgery, 2012, Volume 37, issue 3, p427-433</ref><br> <br>
The treatment algorithm is also influenced by the age and profession/hobbies of the patient.


== Physical Therapy Management    ==
Untreated or malreduced fractures can lead to secondary osteoarthritis. Osteoarthritis or malunion can cause significant pain and functional decline.<ref name=":1" /><sup></sup><sup></sup><sup></sup>


=== Physical Therapy Management ===
<br>Generally, hand fractures are treated by immobilization with a cast or splint regardless of whether surgical or conservative treatment was required. Physical therapists and / or occupational therapists are usually heavily involved in creating and adapting these in consultation with the treating team or surgeon. Protocols for rehabilitation must be based&nbsp;upon stability of the fracture and fracture management (operative or nonoperative).
<br>Generally, hand fractures are treated by immobilization with a cast or splint regardless of whether surgical or conservative treatment was required. Physical therapists and / or occupational therapists are usually heavily involved in creating and adapting these in consultation with the treating team or surgeon. Protocols for rehabilitation must be based&nbsp;upon stability of the fracture and fracture management (operative or nonoperative).


Revision as of 07:21, 21 March 2020

Original Editor - Annelies Noppe Top Contributors - Claire Knott, Annelies Noppe, Lucinda hampton, Nikhil Benhur Abburi, WikiSysop and Kim Jackson

Definition/Description[edit | edit source]


A Bennett fracture is a fracture of the base of the thumb resulting from forced abduction of the first metacarpal. It is defined as an intra-articular two-part fracture of the base of the first metacarpal bone.[1]

Despite a relatively simple appearance on radiographs, Bennett fractures are considered unstable.

In evaluating and treating these fractures positioning the patient with thumb extension (hitchhikers position) should be avoided as this will cause further fracture displacement.

If there is a good alignment of the fracture fragments at postsurgical fixation, clinical outcomes are generally good.[2]

Clinically Relevant Anatomy and Pathophysiology[edit | edit source]


The first CMCJ is unique, it has only an articulation between the trapezium and the base of the first metacarpal. The articulation is saddle-shaped which allows greater motion. [3] The ligaments in this joint are the anterior (volar) and posterior oblique ligaments, the anterior and posterior intermetacarpal ligaments, and the dorsal radial ligament. The anterior oblique ligament is the most important for stability in the carpo-metacarpal joint.[4]

The fracture pattern is distinct. The base of the first metacarpal is fractured with intraarticular extension due to the palmar ulnar fragment of the first metacarpal held in place by its ligamentous attachment to the trapezium (known as the anterior oblique ligament) during the axial loading with the rest of the metacarpal moving in the opposite direction and the main fracture line occurring along this point of weakness. Due to this fracture, the first metacarpal shaft subluxes dorsally, proximally, and radially due to the pull of the abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and the adductor pollicus brevis, which remain attached to the fracture fragment.[2]

Differential Diagnosis[edit | edit source]


Other common injuries involving the first metacarpal include Rolando fractures, extra-articular fractures and gamekeepers thumb

The first differentiation clue can be found during the inspection/palpation of the location of the injury. Bennett fractures are associated with pain and weakness of the pinch grasp and swelling and ecchymosis over the carpal metacarpal joint of the thumb. The patient will be unable to perform functional tasks such as tying a shoe or using a key. Possible complications can be infection, malunion or nonunion, arthritis and stiffness with contracture.[5]

Examination[edit | edit source]

If a Bennett fracture is suspected, the subjective history of the patient should include trauma to the hand or thumb followed by immediate pain and swelling or ischemia.[6] The most common mechanism of injury is axial force (compression) applied to the thumb whilst in flexion.

On physical examination a Bennett's fracture of the first carpo metacarpal joint may present with:

  • visible deformity if the fracture is displaced
  • pain and swelling +/- ecchymosis over carpo metacarpal joint of the thumb
  • tenderness to touch
  • warmth over area in acute phase
  • decreased pinch grasp and decreased grip strength13 


Although X-ray films can be used to diagnose this condition, a CT scan should be ordered to evaluate the extent of the damage. On these CT scans a Bennett fracture will present can as an intra-articular fracture and dislocation of base of the first metacarpal. Even though there is a dislocation there should still be a small fragment of the first metacarpal that continues to articulate with trapezium.

Medical Management[edit | edit source]

Non-operative treatment in a thumb spica cast for 3-4 weeks can be considered in stable, non-displaced fractures.

Operative treatment is recommended for unstable fracture patterns and intra-articular displacement of >1 mm. While open reduction and internal fixation with a screw or K-wire are both common practice, screws are often preferred as K-wires must be removed after union.

The treatment algorithm is also influenced by the age and profession/hobbies of the patient.

Untreated or malreduced fractures can lead to secondary osteoarthritis. Osteoarthritis or malunion can cause significant pain and functional decline.[1]

Physical Therapy Management[edit | edit source]


Generally, hand fractures are treated by immobilization with a cast or splint regardless of whether surgical or conservative treatment was required. Physical therapists and / or occupational therapists are usually heavily involved in creating and adapting these in consultation with the treating team or surgeon. Protocols for rehabilitation must be based upon stability of the fracture and fracture management (operative or nonoperative).

Following the immobilisation period, physiotherapists and specialist hand therapists are involved in the facilitation of restoring maximal function to the hand.
.[7] Modalities employed include cryotherapy, joint mobilisation, strengthening & flexibility exercises, dexterity re-education and specific education. Exercise intensity and complexity should be progressed appropriately following designated protocol usually provided by the surgeon.[8][9] Evidence supports the positive impact of early physiotherapy intervention to facilitate optimal return to function and return to work/sport in hand fractures.[10]

References[edit | edit source]

  1. ↑ 1.0 1.1 Radiopedia Bennett Fracture Available from:https://radiopaedia.org/articles/bennett-fracture (last accessed 21.3.2020)
  2. ↑ 2.0 2.1 Carter KR, Nallamothu SV. Bennett Fracture. InStatPearls [Internet] 2019 May 18. StatPearls Publishing. Available from:https://www.ncbi.nlm.nih.gov/books/NBK500035/ (last accessed 21.3.2020)
  3. ↑ C. Brownlie. Bennett Fracture Dislocation: Review and Management; Australian Family Physician vol 40, No. 6, June 2011
  4. ↑ Mark E Baratz, MD; Chief editor: Harris Gellman, Bennett Fracture, Medscap reference http://emedicine.medscape.com/article/1238036-overview#a05(Accessed 5/05/2013)
  5. ↑ KJAER-PETERSEN K. et al.; “Bennett’s fracture”, Journal of Hand Surgery, 1990 Feb; 15(1):58-61
  6. ↑ HOWARD FM.; “Fractures of the basal joint of the thumb”, Clinical Orthopaedics and Related Research, 1987 Jul;(220):46-51
  7. ↑ Dell, P. C., and R. B. Dell. "Management of Carpal Fractures and Dislocations." Hunter - Mackin - Callahan Rehabilitation of the Hand and Upper Extremity. Eds. E. J. Mackin, et al. 5th ed. Philadelphia: Mosby, Inc.,2002. 1171-1184.
  8. ↑ MDGuidelines.com, Return to work is the best measure of healthcare outcomes. www.mdguidelines.com/fracture-fingers-and-thumb (Accessed 5/05/2013)
  9. ↑ Joe Godges, “Physical Therapy Protocols for Conditions of Wrist and Hand Region”, KP So Cal Ortho PT Residency , 2004
  10. ↑ Feehan, L. M., and K. Bassett. "Is There Evidence for Early Mobilization Following an Extraarticular Hand Fracture." Journal of Hand Therapy 24 Nov. 2008
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