- See:
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Distal Radius Frx Menu:
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External Fixators for Distal Radius Frx
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Intra-Articular Fractures of the Distal Radius:
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Unstable Distal Radius Frx
- Radiographs:
- r/o concomitant
scapholunate dissociation;
- Anatomic Considerations:
-
die punch fragment:
- following fixation of the radial styloid fragment, the remaining depressed articular fragments are elevated and reduced;
- reduction is facilitated w/ traction, direct pressure, or with use of a small incision and application of pointed reduction clamps;
- if reduction can not be performed closed, then a limited
open reduction can be performed;
- wires can be inserted transverse across the subchondral portion of the distal radial articlular surface, either thru the ulna
and across the RU joint, or directed transversely thru the radial cortex to lie just under the subchondral surface;
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metaphyseal comminution:
- w/ high energy frxs or w/ metaphyseal comminution, consider combination of
external fixation and bone grafting inorder to
prevent late collapse of the articular reduction;
- Outcome Studies:
- w/ the distal radius in a reduced position, percutaneous K wires are inserted, and then the distraction is released and the wrist is taken out of flexion;
- in the study by CE Dunning et al, the authors investigated the changes in fracture stability when using supplemental
radial styloid pinning in combination with external fixation;
- 8 previously frozen cadaveric upper extremities were mounted in a computer-controlled wrist-loading apparatus;
- this device was used to generate finger and forearm motions through loading relevant tendons.
- unstable extra-articular distal radius fracture was simulated by removing a dorsal wedge from the distal radius metaphysis;
- electromagnetic tracking system measured fragment motion following randomized application of a Hoffman external fixator, a Hoffman external
fixator with 2 supplemental radial styloid pins, and a dorsal 3.5-mm AO plate;
- addition of radial styloid pins to a construct stabilized by an external fixator significantly improved fragment stability,
approaching that achieved with the dorsal AO plate;
- in the report by Scott W. Wolfe et al, the authors simulated unstable extra-articular distal radius fractures
were created in 7 fresh-frozen cadaveric upper extremities and stabilized using 4 different external fixators;
- physiologic muscle tension across the wrist was simulated by application of 40-N load distributed among the wrist tendons;
- fracture stability was reassessed for each of the constructs after augmentation of the fracture fragments with a single dorsal transfixion K-wire;
- K-wire augmentation demonstrated a significant reduction in motion of the distal radial fragment of at least 40% in all 3 rotational planes;
- for flexion/extension, the reduction in motion was from 4.5° to 2.6°.
- for radial/ulnar deviation, the range of motion decreased from 3.0° to 1.5°.
- rotational motion declined from an average of 3.2° to 1.2°.
- addition of the single dorsal transfixion K-wire significantly improved stability of each of the 4 fixators in at least 1 of the 3 planes in which motion was measured;
- data supported the concept of K-wire augmentation for increasing stability of an unstable extra-articular distal radius fracture regardless of the type of external fixator that is used;
- references:
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Intraarticular fractures of the distal radius: a cadaveric study to determine if ligamentotaxis restores radiopalmar tilt.
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Severe fractures of the distal radius: effect of amount and duration of external fixator distraction on outcome.
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Biomechanical analysis of pin placement and pin size for external fixation of distal radius fractures.
- Supplemental pinning improves the stability of external fixation in distal radius fractures during simulated finger and forearm motion
Cynthia E. Dunning.
J Hand Surg 1999;24A:992-1000
- A biomechanical comparison of different wrist external fixators with and without K-wire augmentation
Scott W. Wolfe
J Hand Surg 1999;24A:516-524
- Specific Techniques:
- which ever technique is used, it is essential to hold the fracture closed reduced as possible while the pins are inserted inorder
that there is minimal skin traction against the pins;
- consider positioning the distal forearm on a stack of towels which allows the wrist be maximally palmar flexed which helps with the reduction, which facilitates pin
insertion (hand and thumb are moved out of the way), and which allows easy flouroscopy since the distal forearm rests parallel to the ground on the towels;
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extra-focal pinning techniques:
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Kapandji's Technique:
- ref:
Two Procedures for Kirschner Wire Osteosynthesis of Distal Radial Fractures. A randomized trial.
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dorsal pin placement:
- single dorsal transfixion K-wire yields the greatest reduction in fragment motion in the flexion/extension plane;
- single 0.065-inch (1.6 mm) K-wire is used to augment fixation;
- wire is drilled at a 45° angle in the sagittal plane from the dorsal lip of the distal radius,
across the osteotomy site and through the volar cortex (dorsal transfixion wire);
- starting point is positioned just distal to Lister's tubercle;
- ref: Dorsal pin placement and external fixation for correction of dorsal tilt in fractures of the distal radius.
Braun RM, Gellman H. J Hand Surg 1994;19A:653-655.
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trans-ulnar technique:
- ulnar-radial pinning with fixation of the
DRUJ
- K wires are placed thru distal ulna into the reduced distal radius;
- technique avoid dorsal sensory branch of radial nerve;
- there is enhance stability with this technique since there is bicortical pin placement thru the ulna;
- disadvantage: need to immobilize R-U joint w/ long arm cast;
- references:
- DePalma: (JBJS, 1952; 34A: 651-662)
- The history and evolution of percutaneous pinning of displaced distal radius fractures. Rayhack, JM.
Orthop. Clin. North Am. 24: 287-300. 1993.
- Trans-ulnar percutaneous pinning of displaced distal radius fractures:
a preliminary report. Rayhack, JM.
J. Orthop. Trauma. 3: 107. 1989.
- Bone Grafting: (see
bone graft harvest techniques);
- elevation of impacted fracture fragments often results in a metaphyseal fracture defect;
- bone grafting via a limited incision over the frx site fills in the fracture site defect and helps prevent fracture collapse;
- the bone graft attempts to hold the reduction in place, and in a sense helps take the place of external fixation;
- it is often easier to perform percutaneous pinning and bone grafting at 10 days from injury since this allows the frx site to become slightly sticky;
- references:
- Augmentation of distal radius fracture fixation with Coralline hydroxyapatite bone graft substitute.
SW Wolfe et al.
J. Hand Surgery.
Vol 24-A. No 4. July 1999. p 816.
- Assessment of Reduction: Is external fixation necessary?
- in an
unstable distal radius frx w/ inadquate reduction consider the addition of
external fixation + K wires;
- as noted in the study by Trumble et al 1998, external fixation provided clear advantages in specific situations;
- in older patients, pain relief, grip strength, and ROM were significantly better when external fixation was used;
- in younger patients, external fixation provided consistently better results when there was comminution in 2 or more cortices or
when there was comminution of one surface which was greater than 50% of the metaphyseal diameter;
- in their study, restoration of
radial length was more important than dorsal tilt or radial tilt, and external fixation
afforded better restoration of length than pinning and casting;
- Compications:
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RSD may result from pin injury to the superficial radial sensory nerve;
- RSD is avoided by making small incisions over the pin insertion site and by spreading with a hemostat;
- if a surgical assistant is available, then he/she can help maintain the reduction while the surgeon
uses a soft tissue protector to prevent the radial nerve from winding around the pin;
- if an assistant is not available consider applying a lubricant (K-Y) to the pin;
- Case Examples:
- this 40 year old patient underwent application of a
external fixator prior to insertion of pins;
- note that prior to pin insertion, the external fixator was distracted to help maintain the reduction, but at the
end of the case, the distraction was released and the reduction was rechecked w/ flouro;
- it is essential that the MP joints achieve full flexion at the end of the case, as
overdistraction can lead to MP join clawing;
Complications of distal radial fractures: pins and plaster treatment.
Unstable distal radius fractures treated by modified Kirschner wire pinning: anatomic considerations, technique, and results.
Percutaneous and limited open reduction of the articular surface of the distal radius.
Unstable Distal Radius Fractures Treated by Modified Kirschner Wire Pinning: Anatomic Considerations, Technique, and Results.
Treatment of comminuted distal radius fractures with pins and plaster.
Percutaneous Pinning of Distal Radius Fractures: A Biomechanical Study.
SH Naidu MD, JT Capo, M. Moulton MD, W. Ciccone II MD, A. Radin PhD.
J Hand Surg. 22-A: 252-257. 1997.
Intrafocal (Kapandji) pinning of distal radius fractures with and without external fixation.
TE Trumble et al.
J. Hand Surg. Vol 23-A. No 3. May 1998. p 381.
Biodegradable rods versus Kirschner wire fixation of wrist fractures. A randomised trial.
The thermal effects of skeletal fixation-pin insertion in bone.
