AAHS ASPN ASRM - 2013 Annual Meeting - American Association ...

A second parallel 0.045-inch k-wire is passed through the distal metaphysis or condlye of the middle phalanx. The free ends of this wire are
also bent at a right angle and directed distally. This wire is parallel to the first wire and its ends are also fashioned into hooks for attachment
of the dental loops. The proximal and distal pins are bent into hook form with a distance between the hooks of 2.5 cm. These two wires bridge
the joint and with the dental loop rubber bands become the engine for continuous distraction to maintain concentric joint reduction.
Ligamentous traction maintains reduction by transferring the forces of distraction to the surrounding soft tissue of the joint, which hold the
fracture alignment. The final K-wire is parallel to other two wires and passes through the mid-diaphysis of the middle phalanx in the mid-axial
line. Its free ends are cut short and bent around the limbs of the first wire to maintain the alignment of the first wire in the same plane with
the digit as it courses through its flexion and extension arc of motion. This wire is provides a palmar translatory moment to aid in balancing
the dorsally-directed forces of displacement. Dental loop rubber bands are then applied between the two hooks in sufficient quantity (usually
three for each pair of hooks) to distract the joint and maintain its reduction throughout full range of motion. Joint reduction through a complete
arc of motion is confirmed with radiographic imaging.
Postoperative Management
Post-operatively, successful restoration of hand function is greatly aided by supervised hand therapy for both active and passive
motion at both interphalangeal joints. Patients are started on an immediate gentle motion protocol within a few days following surgery as
swelling decreases and joint motion increases . Weekly radiographs are obtained to confirm joint reduction . If dorsal subluxation is identified,
applying more dental loop rubber bands until reduction is obtained increases traction. This is a powerful distraction device, and if over distraction
is detected, the number of rubber bands used for traction is reduced. Local wound care to pin tract sites is provided once a day with dilute
hydrogen peroxide and sterile cotton swabs. The use of medicated ointments for pin tract care is not recommended, as these compounds prevent
drainage, and may cause contact dermatitis with prolonged use. It has been shown with this dynamic splint that full recovery of flexion
can be attained . Strict compliance with a supervised hand rehabilitation program is critical if patients are to regain full active extension of the
PIP joint. The device is removed when radiographs demonstrate bony union, usually at five to six weeks. Prior to device removal, lateral radiographs
with the rubber bands removed are obtained in full flexion and extension to confirm that concentric joint reduction is maintained out
of traction . Therapy is continued after splint removal for one to two months, to recover motion and strengthen the hand.
Results
We reported on a series of 9 fracture-dislocations of the PIP joint , treated with this dynamic distraction external fixation device. All
fractures healed without complications recurrent dorsal dislocation or infection. Average flexion measured 94 degrees (range 85 to 115) and
average extension deficit measured 14.5 degrees (range 0 to 35). DIP motion averaged 60 degrees of flexion and 9.5 degrees extension lag.
One patient required a return to the operating room at 5 months for extensor tenolysis, and had restoration of active extension measuring 7
degrees. While all patients recovered functional digital flexion, there was a marked improvement in recovery of extension among the 5 patients
treated with supervised hand therapy when compared with a group of 4 patients treated exclusively with a home exercise program.
Figures
Below are schematic representation and photographs of the dynamic traction external fixator created intraoperatively from Kirschner
wires and dental bands that spans the proximal interphalangeal joint and provides continuous traction throughout a full range of motion of
the joint. The dynamic distraction splint is assembled using three 0.045-inch Kirschner wires placed parallel to each other and perpendicular to
the lateral axis of the digit. Arrow A points to the placement of the first 0.045 inch K-wire is placed through the rotational center of the head
of the proximal phalanx and is parallel to the joint surface. Arrow B points to the placement of the 2nd wire, also parallel to the joint surface
of DIP joint and the first wire. The free ends of both wires are fashioned into hooks for attachment of the dental loops rubber bands. The distance
between the hooks is 2.5cm. The final wire is parallel to the other two wires and passes through the middle phalanx in the mid-axial
line. Its free ends are cut short and bent around the limbs of the first K-wire. This pin acts as a fulcrum to maintain congruent reduction
through a full arc of motion. Dental loop rubber bands are then placed between the two hooks in sufficient quantity (usually three per pair of
hooks) to distract the joint and maintain its reduction throughout full range of motion. Finally, joint reduction through a complete arc of
motion is confirmed with radiographic imaging.
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