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Technique

Double Barrel Screw Fixation for Proximal Phalanx Fracture

Gray, Robert R. L. MD*; Rubio, Francisco MD; Heifner, John J. MD; Hoekzema, Nathan A. MD§; Mercer, Deana M. MD

Author Information
Techniques in Hand & Upper Extremity Surgery: April 06, 2022 - Volume - Issue - 10.1097/BTH.0000000000000387
doi: 10.1097/BTH.0000000000000387
  • Open
  • PAP

Abstract

Hand fractures account for 19% of all adult fractures and proximal phalanx fractures account for 22% of all hand fractures.1Treatment options for these fractures are determined by the stability of the fracture pattern at the time of presentation. Stable fractures can be conservatively managed with splinting and protected motion. Several fixation options are available for unstable fractures requiring operative treatment, each with notable characteristics. Kirschner wire (K-wire) fixation minimizes soft tissue insult, but fixation strength is limited, and a period of postoperative immobilization is often required.2,3Plate and screw constructs offer robust fixation strength but require more extensive dissection which can lead to soft tissue adhesions, flexion contracture, subsequent loss of motion, and functional deficits.4,5Intramedullary compression screws have yielded promising results,6,7but questions remain about their efficacy for certain fracture patterns.8The ideal fixation construct would impart ample rigidity to resist the deforming forces which occur during early motion while also minimizing soft tissue disruption.

A common proximal phalanx fracture presentation includes an apex palmar angular deformity. This is due to the force of the intrinsic muscles on the proximal fracture fragment and of the central slip on the middle phalanx leading to hyperextension of the distal fragment. When anatomic reduction is not attained or when loss of fixation occurs, shortening with resultant extensor lag is a predictable complication. Long oblique and spiral fracture patterns have a greater tendency to rotate and shorten, increasing the propensity for extensor lag and rotational malalignment.9Some authors have discouraged the use of intramedullary screw fixation for these fracture patterns due to the potential for shortening and rotation.8

Dual intramedullary screw constructs provide the advantage of additional stability in comminuted or length-unstable fractures compared with single screw fixation. Del Pinal et al8described a retrograde centrally placed cannulated screw with an additional smaller diameter cannulated screw. Two patterns of dual screw fixation were described. One technique used an oblique “Y-strutting” screw, typically in metacarpal neck fractures, and the other used a parallel “axial strutting” screw in the dorsal aspect of the proximal phalanx. The “strutting” terminology is derived from the conceptual origin in structural engineering. Gaspar et al7describe a slightly different technique involving antegrade insertion of dual cannulated headless screws through the base of the proximal phalanx with a crossed configuration. Both of these techniques necessitate an intentional split of the extensor mechanism, and Gaspar’s crossed screw technique risks malrotation when used in canals that are not wide enough for 2 screws in the anteroposterior dimension. There is a biomechanical rationale for the augmented stability of dual screw constructs. Screw convergence provides resistance to shortening and screws of similar length more widely distribute implant loads. Maximizing screw length provides greater resistance to bending and rotational forces and greater bony purchase for stability.10

Here we describe a technique of percutaneous dual antegrade screw fixation for proximal phalanx fractures with minimal violation of the extensor mechanism which facilitates immediate postoperative range of motion without splinting, utilizing only a soft dressing and buddy strapping.

ANATOMY

Extension at the second to fifth metacarpophalangeal (MCP) joints is actuated by the extensor digitorum communis tendon slip to each digit and the sagittal bands.11The extrinsic extensor digitorum communis tendons run over the MCP joints, then trifurcate in a central slip that inserts at the base of the middle phalanx, and into 2 lateral slips that finally conjoin at the dorsal base of the distal phalanx as a terminal extensor tendon.12Iatrogenic disruption or injury to this extensor mechanism should be minimized during placement of fracture fixation.

TECHNIQUE

The patient is placed supine after induction of appropriate anesthesia with the arm extended onto a hand table. Anesthesia options include regional or local block with or without adjuvant sedation. A tourniquet is not necessary for closed fractures given the percutaneous nature of the procedure. A mini c-arm is utilized to assess reduction. The MCP joint is flexed ~60 degrees over a rolled towel or Esmarch as a bump. Dorsally directed pressure is applied to the proximal phalangeal base to subluxate the base dorsally with respect to the metacarpal head. A 0.062-inch K-wire is advanced centrally through the base of the proximal phalanx into the intramedullary canal to maintain reduction (Fig. 1). In very unstable fractures, this wire can be placed over the metacarpal head into the proximal phalanx base in a dorsally subluxated position then advanced after the shaft is reduced to the base, provisionally stabilizing the reduction. This allows antegrade access to the proximal phalanx intramedullary canal from the phalangeal base. After fracture reduction is confirmed radiographically, flexion at the MCP is manually maintained throughout the process of fixation. Small stab incisions are made at the level of the collateral recess of the metacarpal heads, both medially and laterally. A guidewire is inserted through each incision into the proximal phalanx base on the radial and ulnar aspect of the central wire, minimizing trauma to the central portion of the extensor mechanism. The wire is advanced distally across the fracture site, spanning the entire length of the phalanx into the subchondral bone of the proximal phalangeal head. If placement into the proximal phalangeal head is not practical, maximizing the length of the wire is advantageous. Subchondral placement helps prevent premature wire pullout during drilling. A second guidewire is placed on the other side of the central wire in similar manner (Figs. 2A, B). The type of screws used for fixation will be determined by surgeon preference and intramedullary canal diameter. The anteroposterior width at the isthmus of the phalangeal neck is the limiting dimension. A smaller diameter screw often permits a longer length compared to larger diameter screws. To protect surrounding structures, drilling is done manually. If smaller diameter noncannulated screws are used due to intramedullary space constraints, each guidewire is removed before screw insertion. If cannulated screws are used, the guide wire remains in position during drilling and screw insertion. Depth measurements are taken to determine appropriate screw length. After drilling and measurement, the screw is inserted using a hand driver. Drilling, measuring, and screw placement are done in sequential manner for each screw in order to maintain stable reduction with either a wire or screw crossing the fracture site along with the central wire at all times (Figs. 3A, B). Maintaining the hand in a fist position from the placement of the guidewires until the placement of the final screw aids in reduction and minimizes the potential for malrotation. Special attention should be paid to keeping the hand in a fist position during screw insertion, as the torque can rotate the bone through the fracture site if the reduction is not maintained.

F1
FIGURE 1:
Lateral fluoroscopy showing dorsal subluxation of the proximal phalangeal base to facilitate antegrade introduction of a guide wire to attain reduction.
F2
FIGURE 2:
Anteroposterior (A) and lateral (B) fluoroscopy showing guide wires inserted on the radial and ulnar sides of the centrally placed reduction wire.
F3
FIGURE 3:
Anteroposterior fluoroscopy showing insertion of first (A) and second (B) intramedullary headless cannulated screw over a guide wire.

If difficulty is encountered finding the cortical entry during noncannulated screw insertion, the wire can be reinserted into the drilled entry hole and a Freer elevator is placed under the wire. The elevator is held in place while the wire is removed, and the screw is then guided into the entry hole over the top of the elevator. Alternatively, if cannulated screws are used, the drill bit may be used as an entry awl with the guide wire being placed through it once the path is re-established. Maintenance of fracture reduction and alignment are confirmed with fluoroscopic imaging (Figs. 4A, B). Closure of the percutaneous incision is done with absorbable suture and a buddy strap with a soft dressing is applied. Active and passive range of motion is begun immediately following surgery. The finger is typically strapped or taped to a neighboring digit for added stabilization during the postoperative period.

F4
FIGURE 4:
Anteroposterior (A) and lateral (B) fluoroscopy showing final construct of dual intramedullary headless screws used for fixation of unstable proximal phalanx fracture.

EXPECTED OUTCOMES

We believe one of the significant advantages of this technique over temporary percutaneous K-wire fixation is that the soft tissue envelope remain untethered as the screw is completely contained within bone. When compared with single screw fixation techniques, our technique provides ample stability which allows immediate motion without the need for rigid immobilization. Furthermore, the hand drilling and peripheral insertion of screws minimizes extensor tendon violation. With increased attention given to the financial burden of surgical procedures, implant cost is an important consideration in these cases. Our technique of 2 screws comes with a higher cost than the commonly used technique of K-wires. With the advantages of immediate motion which may reduce rehabilitation time and the rigidity of fixation which may reduce the risk of failure, we think this technique provides added value.

COMPLICATIONS

Expected complications are similar to other methods of fracture fixation including infection, malunion, nonunion, or implant failure. Management of malunion or nonunion with this fixation method is similar to other techniques. More specific to this percutaneous fixation method is the possibility of errant screw trajectory and subsequent loss of screw capture by the screw driver before placement of the screw in the intended position. To avoid this complication, one must ensure appropriate fracture reduction on orthogonal views before advancing the wires and screws.

REFERENCES

1. Van Onselen EBH, Karim RB, Hage JJ, et al.Prevalence and distribution of hand fractures.J Hand Surg Eur Vol.2016;28:491–495.
2. Stahl S, Schwartz O.Complications of K-wire fixation of fractures and dislocations in the hand and wrist.Arch Orthop Trauma Surg.2001;121:527–530.
3. Hsu LP, Schwartz EG, Kalainov DM, et al.Complications of K-wire fixation in procedures involving the hand and wrist.J Hand Surg Am.2011;36:610–616.
4. Page SM, Stern PJ.Complications and range of motion following plate fixation of metacarpal and phalangeal fractures.J Hand Surg Am.1998;23:827–832.
5. Robinson LP, Gaspar MP, Strohl AB, et al.Dorsal versus lateral plate fixation of finger proximal phalangeal fractures: a retrospective study.Arch Orthop Trauma Surg.2017;137:567–572.
6. Giesen T, Gazzola R, Poggetti A, et al.Intramedullary headless screw fixation for fractures of the proximal and middle phalanges in the digits of the hand: a review of 31 consecutive fractures.J Hand Surg Eur Vol.2016;41:688–694.
7. Gaspar MP, Gandhi SD, Culp RW, et al.Dual antegrade intramedullary headless screw fixation for treatment of unstable proximal phalanx fractures.Hand (NY).2019;14:494–499.
8. del Pinal F, Moraleda E, Ruas JS, et al.Minimally invasive fixation of fractures of the phalanges and metacarpals with intramedullary cannulated headless compression screws.J Hand Surg Am.2015;40:692–700.
9. Henry MH.Fractures of the proximal phalanx and metacarpals in the hand: preferred methods of stabilization.J Am Acad Orthop Surg.2008;16:586–595.
10. Patel S, Guigale JM, Debski RE, et al.Effect of screw length and geometry on interfragmentary compression in a simulated proximal pole scaphoid fracture model.Hand (NY).2018;15:378–383.
11. Jovanovic N, Aldlyami E, Saraj B, et al.Intramedullary percutaneous fixation of extra-articular proximal and middle phalanx fractures.Tech Hand Up Extrem Surg.2018;22:51–56.
12. Colzani G, Tos P, Battiston B, et al.Traumatic extensor tendon injuries to the hand: clinical anatomy, biomechanics, and surgical procedure review.J Hand Microsurg.2016;8:2–12.
Keywords:

proximal phalanx fracture; PIP fracture; unstable PIP fracture; PIP fracture dislocation

Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.