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Written by J. Jupiter
Tuesday, 08 November 2005

Plate Fixation of Osteoporotic Wrist Fractures

Jesse B. Jupiter, M.D.
Hansjörg Wyss/AO Professor
Harvard Medical School
Chief Hand Surgery
Dept. Orthopaedic Surgery
Massachusetts General Hospital

I. The Problem

1. Osteoporosis and wrist fractures
   • Diminished metaphyseal trabeculation
   • Poor holding power of conventional screw fixation.
2. Age is not a good indicator of functional needs or activity level
   • 40% of senior citizens consider their health as very good or excellent.
   • 30% over age 85 consider their health excellent or good.
   • Many elderly are independent:
     • 23% of 65-74 year olds live alone
     • 41% of >75 year olds live alone.
   • Standard outcomes do not:
     • Address overall activity level
     • Evaluate difficulty but not frequency of an activity.
   • Two instruments useful:
     • Patients rated write score (PRWE)
     • Physical activity scale of the elderly (PASE)

II. Fixation in Osteoporotic Bone-angular Stable Implants

1. Biomechanics of regular plate and screw fixation
   • Different plate designs and methods but one common element—compression plate to bone=friction.
   • Stability of plate depends upon adequate bone quality and purchase of screws in bone.
   • Recognized deficient screw anchorage in porotic bone.
2. Principles of locked plating systems
   • Angular stable implant-bone interface.
   • The double lead thread engages and threads the screw into the plate hole. This locks the screw axially and provides angular stability, independent of the quality of the bone.
   • The pullout of regular plate-screw constructs happens as a result of a bending load—the screws are pulled out sequentially.
   • The resistance of locking screws under bending load is higher—strongly increases the area of resistance.
   • The lowest resistance to pullout occurs when the screws are loaded in a pure axial direction.
   • The advantages of locked plating. [“Internal fixator.”]
     1. Angular stability screws.
     2. No need for accurate plate contouring.
     3. Less periosteal damage.
     4. Less screw loosening.

III. Why Plating is a viable approach.

1. Size-adapted, pre-contoured implants.
   • Angular stable subchondral support effective even with compression failure of metaphysis leaving a void.
2. Versatile virtually all indications
   • Dorsally displaced Colles’
   • Dorsopalinar fixation.
3. Angular stable fixation eliminates fixation in osteoporotic bone with screws.
4. Less tendon irritation, less need for implant removal.
   • Palmar approach effective.

IV. Pitfalls and Pearls

1. Volar metaphysical fracture.
   • Risk of dorsal translation of distal fragment.
2. Volar shearing fracture.
   • Beware of volar-ulnar fragment.
3. Rotated volar lunate facet.
4. Extensive comminution may require dorsal and volar approaches.

V. Outcome

1. Jupiter et al. JHS
   • 25 patients, average age 67 years.
   • All active lifestyle.
   • Average outcome score PRWE wnl in 12.
   • PASE all at normal or above minimal complications.
2. Orbay and Fernandez
   • 26 patients.
   • All 75 years and older.
   • DASH score at one year, excellent.
   Few complications.

Last Updated ( Tuesday, 08 November 2005 )