Avascular Necrosis of the Hand and Wrist



Avascular Necrosis of the Hand and Wrist


Michael Guju

Evan H. Horowitz

Francisco A. Schwartz-Fernandes



The article by Gelberman and Gross on the vascularity of the wrist divided the bones of the wrist into three groups based on decreasing risk of avascular necrosis (AVN).1
























Group


Bones


At-Risk Anatomy


Group 1


Scaphoid, capitate, and 80% of lunate


Supplied by only one vessel or had large areas of bone only supplied by one vessel. Most vulnerable group to avascular necrosis (AVN)


Group 2


Hamate and trapezoid


Do not have internal anastomosis. Minimal risk of AVN


Group 3


Trapezium, triquetrum, pisiform, and 92% of lunates


Have rich internal anastomoses. Least risk for AVN


They further expanded their examination by examining the extent and type of vascular occlusion required to cause AVN (Table 22.1).


AVN DISORDERS


Scaphoid



  • Cause of AVN—trauma



    • Epidemiology



      • Osteonecrosis is said to occur in 13% to 50% of cases of fracture of the scaphoid.


      • Incidence of osteonecrosis is even higher in those with involvement of the proximal one-fifth of the scaphoid.2,3


  • Anatomy



    • The blood supply of the scaphoid is primarily from the radial artery via the artery to the dorsal ridge of the scaphoid.




      • The branches enter the scaphoid via foramina at the dorsal ridge at the level of the waist of the scaphoid.4,5


    • The proximal pole of the scaphoid relies entirely on this interosseous blood supply.


  • Pathophysiology



    • Low-energy falls from a standing height were most common (40.4%).


    • Males are significantly more likely to sustain their fracture after a high-energy injury.6


  • Clinical history



    • Scaphoid fractures are commonly seen in young, healthy individuals and may occur as a result of a fall on the outstretched arm or a forced dorsiflexion injury of the wrist.2


  • Physical examination



    • A reliable correlation exists between scaphoid fracture and pain provoked by deep palpation at the volar tubercle of the scaphoid, which is the first bony prominence distal to the volar distal radius. Scaphoid fracture is not very likely when tubercle palpation does not provoke pain in the snuffbox.


  • Special provocation maneuvers



    • Watson (scaphoid shift) test—The patient sits with the forearm pronated. The examiner takes the patient’s wrist into full ulnar deviation and extension. The examiner presses the patient’s thumb with his/her other hand and then begins radial deviation and flexion of the patient’s hand.


    • Scaphoid stress test—The patient sits while the examiner holds the patient’s wrist with one hand, with the examiner applying pressure with his/her thumb over the patient’s distal scaphoid. The patient then attempts radial deviation of the wrist.



  • Classification/imaging



    • A computed tomography bone scan in the long axis of the scaphoid is the best means of differentiating between stable and unstable fractures. Type B fractures should be corrected operatively (Table 22.2).7


  • Preiser’s disease



    • Preiser’s disease is a rare condition where ischemia and necrosis of the scaphoid bone occur bilaterally without previous fracture. The lack of perfusion to the proximal pole is often associated with prolonged use of corticosteroids or chemotherapy. X-ray and magnetic resonance imaging (MRI) are used to confirm diagnosis.


  • Classification/imaging




  • Treatment



    • Initial treatment is immobilization


    • There are two surgical procedures to treat Preiser’s disease.



      • Proximal row carpectomy (PRC), which is the removal of the proximal row of carpal bones (scaphoid, lunate, and triquetrum)


      • Four-corner fusion with scaphoid excision, which is the removal of the scaphoid bone and fixing of the remaining wrist bones using a “spider plate” or wires (Figure 22.1)8,9








TABLE 22.1 Risk of Avascular Necrosis According to Gelberman and Gross1

















Bones


Type of Occlusion Resulting in AVN


Scaphoid and capitate


Intraosseous disruption


Lunates (minority)


Extraosseous disruption


Lunates (majority)


Both extraosseous and intraosseous disruption


AVN, avascular necrosis.









TABLE 22.2 Scaphoid Fracture—Herbert Classification












































A


Acute, stable


A1


Tubercle


A2


Nondisplaced crack in the waist


B


Acute, unstable


B1


Oblique, distal third


B2


Displaced or mobile, waist


B3


Proximal pole


B4


Fracture-dislocation


B5


Comminuted


C


Delayed union


D


Established nonunion


D1


Fibrous


D2


Sclerotic


Descriptive


Special studies


Scaphoid view


Kinematic wrist views









TABLE 22.3 Preiser Disease Classification38




















Stage


Radiologic Findings


I


Normal radiograph. Abnormal findings on MRI. Positive bone scan


II


Proximal pole sclerosis of the scaphoid. Generalized osteoporosis


III


Fragmentation of the proximal scaphoid pole with/without pathological fracture


IV


Periscaphoid collapse, fragmentation, and osteoarthritis


Abbreviation: MRI, magnetic resonance imaging.







FIGURE 22.1 Four-corner fusion, x-rays on anteroposterior (A) and lateral (B) views.


LUNATE

May 7, 2019 | Posted by in ORTHOPEDIC | Comments Off on Avascular Necrosis of the Hand and Wrist
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