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ening of the frame in the follow-up period. What To Avoid 1. Do not place the pins percutaneously. This may increase the risk of cutaneous sensory nerve injury. 2. Do not leave the wrist in over-distraction as this will greatly increase the potential for finger stiffness and delayed union. 3. Avoid excessive ulnar deviation and/or flexion. If such positioning is necessary to maintain align- ment, supplemental fixation should be considered. 4. Avoid tight closure of the skin around the pins as this will lead to skin irritation. 5. Avoid tethering tendons and muscles with the pins. Postoperative Care Issues 1. A light compressive dressing is applied around the pin sites and is changed at the first follow-up visit. 2. Overnight hospitalization for observation may be indicated. 3. Immediate finger motion is emphasized and assis- tance from an occupational therapist may be help- ful in the early postoperative period. 4. Do not neglect range of motion activities for the forearm, elbow, and shoulder. 5. Remove stitches after 10 days. 6. Obtain follow-up radiographs at 1, 3, and 6 weeks. 7. The timing of fixator removal is controversial. Generally, the fixator is kept in place for approxi- mately 6 weeks. Earlier removal can occur in the set- ting of bone grafting and/or supplemental fixation. Operative Technique 1. With the patient supine, ensure good access to the dorsal-radial aspect of the wrist. 2. The extremity is prepared and draped free in the usual sterile fashion. The planned incision sites are shaved. 3. The primary surgeon is seated at the patient’s axilla. The fluoroscopy unit is positioned for easy access to the surgical field, either at the end of the hand table extension or opposite the primary surgeon. 4. First perform a closed reduction maneuver, then proceed with frame application; 10 to 12 pounds of finger-trap traction can be helpful. 5. The tourniquet should be inflated prior to pin placement. 6. Pins should be oriented 35 to 45 degrees from the frontal plane to avoid interference with thumb motion. Constructing the frame at this angle will also permit unobstructed lateral radiographs of the distal radius. 7. Distal pin placement is performed through either two stab incisions or a single longitudinal incision (Figs. 16–1A and 1B). 1 6 D I S TA L R A D I U S F R A C T U R E S ( E X T E R N A L F I X AT I O N ) 9 9 a. When dissecting down to the bone, care should be taken to avoid damage to dorsal veins and branches of the radial sensory nerve. b. Visualize the central portion of the index metacarpal to facilitate sound bicortical pur- chase during pin placement. c. Pin guides included with the external fixator sys- tem are generally used to assist in pre-drilling and pin placement. d. The AO/ASIF system allows for metacarpal pins to be placed at a converging angle to maximize bone purchase (a converging angle of 40 to 60 degrees is recommended). Many newer fixa- tor systems necessitate pin placement perpendi- cular to the metacarpal shaft. e. The more proximal of the 2 pins can also be engaged into the radial cortex of the third metacarpal for additional purchase strength. This will often require placement of all fixator pins in line with the frontal plane. f. Avoid tethering the first dorsal interosseous muscle when placing pins. 8. Proximal pin placement is generally in the middle to distal portion of the radius. a. The proximal pins should be oriented in the same plane as the distal pins (35 to 45 degrees from the frontal plane). b. An open approach is recommended as blind pin placement risks injury to the radial sensory nerve and branches of the lateral antebrachial cutaneous nerve. The incision is generally 4 to 5 cm in length, centered at the junction of the middle and distal one-thirds of the radius. c. The interval between the extensor carpi radialis longus and extensor carpi radialis brevis tendons is identified and developed. The abductor polli- cis longus and the extensor pollicis brevis ten- dons are frequently visualized at the distal end of the incision (Fig. 16–2). d. The dorsal and volar margins of the radial shaft should be exposed to ensure central placement of the pins. e. Templates or guides can be used to facilitate pre- drilling and pin placement. 9. Verify bicortical fixation of all 4 fixator pins with fluoroscopy. 10. Irrigate the wounds and close the skin edges loosely with interrupted sutures. 11. Deflate the tourniquet. 12. Assemble the fixator frame onto the pins, taking into account radiographic accessibility to the frac- ture site. 13. Before tightening the fixator, make final adjust- ments to the fracture reduction. a. At this stage, K-wires can be used as joysticks for fracture manipulation and also as supplemental fixation. b. Fine tuning of fracture alignment is possible with most fixator systems. c. The ideal position of the wrist is neutral flex- ion/extension and radial/ulnar deviation. If excessive flexion or ulnar deviation is required to maintain fracture alignment, supplemental fixation is recommended (Fig. 16–3). d. Check the carpus under fluoroscopy for over-dis- traction. The radiocarpal interval should be no more than 1 to 2 mm wider than the midcarpal interval on the AP projection. The carpal height index (CHI) can also be helpful in determining over-distraction. Caution is advised in over- reliance upon radiographic parameters, how- ever, as recent investigators have questioned their reliability. e. Make sure that the fingers can be easily flexed to a complete fist as an additional check against over-distraction. 14. If K-wires have been placed, the exposed tips are either bent or capped. 15. Check the skin around the pins for excessive ten- sion and make relaxing skin incisions as necessary. 16. A light compressive dressing is applied and the patient is transferred to the recovery room once stable. 17. A postoperative sling can be used for comfort. Instructions are given to begin early finger motion and to elevate and ice the wrist to reduce postoper- ative swelling. 1 0 0 W R I S T A N D H A N D 1 0 1 Extensor digitorum communis Extensor indicis proprius Index extensors retracted First dorsal interosseous muscle Superficial branch of radial nerve Frontal plane Metacarpal 2 A B Figure 16–1 (A) Distal pin placement. Distal pin placement is performed through either two stab incisions or a single longitudinal incision. When dissecting down to the bone, care should be taken to avoid damage to dorsal veins and branches of the radial sensory nerve. (B) Distal pin placement. Seat the pins at a converging angle of 40 to 60 degrees to maximize metacarpal bone purchase. Orient both pins 35 to 45 degrees from the frontal plane to avoid interference with thumb motion. 1 0 2 Second and third metacarpal bones Tendons of extensor carpi radialis longus, brevis muscles Adductor pollicis longus muscle Extensor pollicis brevis muscle Extensor carpi radialis brevis muscle Extensor carpi radialis longus muscle Supplemental K-wire fixation at distal radius Figure 16–2 Proximal pin placement. For the proximal pins, the incision is generally 4 to 5 cm in length, centered at the junction of the middle and distal one-third of the radius. The interval between the extensor carpi radialis longus and extensor carpi radialis brevis tendons is identified and developed. The abductor pollicis longus and the extensor pollicis brevis tendons are frequently visualized at the distal end of the incision. The dorsal and volar margins of the radial shaft should be exposed to ensure central placement of the pins. Figure 16–3 External fixator placement. The ideal position of the wrist is neutral flexion/extension and radial/ulnar deviation.