TIPS AND TECHNIQUES

A Novel Hook Plate Fixation Technique for the Treatmentof Mallet Fractures

Kanthan Theivendran, BSc, MBBS, Andrew Mahon, MSc, FRCSI(Tr and Orth),and Vaikunthan Rajaratnam, MBBS(Mal), AM(Mal), MBA(USA), FRCS(Ed),

FRCS(Glasg), FICS(USA), Dip Hand Surgery(Eur)

Abstract: Bony mallet injuries are generally treated nonoperatively,but when the fragment involves a significant percentage of thearticular surface, articular incongruity and instability can occur. Anumber of techniques have been described for the fixation of suchfractures and each has its own problems. Anatomic reduction andsecure fixation of small fragments can be challenging. Our objectiveis to describe a new surgical technique using a 1.3-mm hook platethat provides good reduction and stable fixation of a mallet fracture,with early mobilization of the distal interphalangeal joint.

Key Words: fracture, hook plate, internal fixation, mallet,open reduction

(Ann Plast Surg 2007;58: 112–115)

The management of mallet fractures of the hand representsa unique and problematic challenge. The mechanism of

injury usually involves axial loading of the fingertip, withhyperextension at the distal interphalangeal (DIP) joint, re-sulting in a fracture of the dorsal lip of the base of the distalphalanx. Treatment modalities range from splinting alone,1–3

which has produced satisfactory results, to operative fixationfor fragments involving more than 30% of the articularsurface, with or without subluxation of DIP joint.4,5

Nonoperative treatments have resulted in chronic insta-bility, joint subluxation, osteoarthritic deformity, resulting incosmetically unacceptable outcomes.4,6 Healing of the bonyfragment with displacement can lead to extensor lag and aswan-neck deformity.2

Various techniques have been described in the literaturefor operative fixation of mallet fractures. These include usingKirschner wires (K-wires),6–10 tension band fixation,4,11 in-ternal suture,12 compression pin fixation,13 screw fixation,14

and volar plate advancement arthroplasty15.

We describe a new technique for open reduction andinternal fixation (ORIF) of mallet fractures using a 1.3-mmhook plate (Teoh Lam-Chuan, Singapore General Hospital,personal communication, 2005).

TECHNIQUEIndication for this procedure includes patients with a

clinical mallet deformity, with radiographic evidence of adorsal intra-articular fracture fragment involving more than30% of the base of the distal phalanx.

The patient is positioned supine on the operating table,with the hand prepared with standard antiseptic solutions. Adigital local anesthetic block is used and a sterile digitaltourniquet for the injured finger. A dorsal approach using a Yincision is made over the fracture site to facilitate adequatemidline exposure of terminal phalanx. The nailbed is elevatedoff the periosteum (in a similar manner to performing avascularized nailbed transfer and avoiding damage to thegerminal matrix) of the distal phalanx. A 1.3-mm 2-holeCompact Hand Set (AO, Davos, Switzerland) plate is modi-fied by cutting the proximal hole with plate cutters (Fig. 1A).The cut ends spring open and are bent volarly into hooks (Fig.1B, C). Two very small longitudinal incisions are made in theterminal tendon. The hooks are passed through these slipsaround the dorsal lip at the distal edge of the fracturefragment. The hooks grab onto the articular surface at thedorsal lip in an area which does not articulate with the middlephalanx, so there is no interference with DIP joint function.The hooks are then used to control and reduce the fracturefragment. A 1.0-mm K-wire can be used to help reduce andhold the fracture fragment temporarily while applying theplate (Fig. 1D, E). The distal end of the plate with thecomplete hole is held onto the distal phalanx using a 6-mmscrew. The self-tapping 6-mm titanium screw is advancedobliquely using a handheld screwdriver, thereby levering onthe distal hole to reduce the fracture (Fig. 1E). The screw isthen advanced perpendicular to the distal phalanx, therebyanchoring the fragment in position (Fig. 1F), and the woundis closed. This provides compression of the fracture fragmentat the fracture site using the “tension band” principle. In mostcases, a modified 2-hole plate can be used; however, for alarger unstable dorsal fragment, a modified 3-hole plate with2 hooks and 2 holes may be required. The longer plate allowsthe titanium screw to be placed in the distal fragment to

Received April 9, 2006, and accepted for publication, after revision, June6, 2006.

From the Birmingham Hand Centre, University Hospital Birmingham, SellyOak Hospital, Birmingham, UK.

No financial support was received for this article.Reprints: K. Theivendran, BSc, MBBS, 81 Pennine Way, Ashby-de-la-

Zouch, Leicestershire, LE65 1EZ, UK. E-mail: kanthan@hotmail.co.uk.Copyright © 2006 by Lippincott Williams & WilkinsISSN: 0148-7043/07/5801-0112DOI: 10.1097/01.sap.0000232858.80450.27

Annals of Plastic Surgery • Volume 58, Number 1, January 2007112

provide secure fixation. A radiographic image intensifier isused to assess reduction. Postoperatively, the injured finger isplaced in a mallet splint for 2 weeks and then protected byimmobilization with a splint for a further 3 weeks. Radio-graphic images are obtained after the procedure to assessbony union.

CASE REPORTA 53-year-old right-hand-dominant writer had injured

his left ring finger after falling on a dry ski slope. He was seenin the emergency department 6 days after the injury. He hadcomplained of pain, swelling, and deformity over the DIPjoint. On clinical examination, there was dorsal tendernessand swelling, with extensor lag at the DIP joint. Radiographsdepicted a dorsal avulsion fracture of the base of the terminal

FIGURE 2. Lateral (A) and anterior-posterior (B) radiographsof a mallet fracture with 50% involvement of articular sur-face.

FIGURE 3. Extension (A) and flexion (B) of the DIP jointshowing excellent range of motion of the ring finger.

FIGURE 1. Operative technique forthe application of the titaniumhook plate and screw.

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phalanx (Fig. 2A, B). The patient was referred to the handsurgeon and underwent an ORIF 2 days later.

There was mild volar subluxation noted under a digitalanesthetic block. Through a dorsal Y incision, the nailbedwas elevated off the periosteum from the proximal part of thedistal phalanx. The exposed fracture fragment was reducedand held temporarily with a single 1.0-mm K-wire. The1.3-mm hook plate was then applied by the usual methoddescribed previously. The DIP joint was immobilized for 2weeks, with protected mobilization for a further 3 weeks.

Six months after the procedure, the patient had 8° to 70°of pain-free range of motion at the DIP joint (Fig. 3). The patienthad returned to normal activities at 5 weeks and had no disabil-ity, with a DASH (disabilities of the arm, shoulder andhand)16,17 score of 0 at 6 months. The fracture had united at 7weeks, with no articular step (Fig. 4). There were no complica-tions, and the patient was satisfied with the treatment.

DISCUSSIONThere have been conflicting reports in the literature

regarding the management of mallet fractures. Nonoperativetreatment has been proposed by Wehbe and Schneider,2

including those with fracture subluxation of the distal pha-lanx. Many authors have advocated operative fixation withlarger dorsal fragments with palmar subluxation.5,6,18 Oper-ative techniques using K-wires,7 tension band wires,4,8 pull-out sutures,19 miniscrews,14 and volar plate arthroplasty15

have been reported.The operative goals for the treatment of mallet fractures

are to provide anatomic reduction with rigid fixation whileallowing early joint motion to prevent contractures at the DIPjoint. Many of the operative procedures described can bedemanding and may obstruct early joint motion. The hookplate technique is relatively simple to perform and provides

anatomic reduction, with stable fixation of a large dorsal bonyfragment. The patient treated by this method had good,pain-free range of motion at the DIP joint, with bony union at7 weeks. The use of the low-profile plate did not cause anyskin irritation or nailbed deformity (Fig. 5), and there was noradiographic evidence of plate loosening. It is generallyindicated that fractures involving less than 30% of the artic-ular surface should be treated conservatively with a malletsplint. However, for a larger displaced fragment, a minimallyinvasive technique of extension-block percutaneous K-wirepinning is easy to perform and is an effective, safe alternativeto the conservative treatment of displaced mallet frac-tures.20 –22 We would advocate this treatment for the mostpart; however, stiffness and swelling may persist as the DIPjoint is rigidly immobilized for up to 6 weeks as comparedwith 2 weeks with the hook plate.

We recommend the use of the hook plate as it offersanatomic reduction, rigid internal fixation with early jointmobilization. This technique provides an alternative andacceptable treatment modality, especially in large dorsalfragment mallet fractures, with or without subluxation of theterminal phalanx.

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FIGURE 5. Dorsal view showing a healed scar with no nail-bed deformity.

FIGURE 4. Lateral (A) and anterior-posterior (B) radiographsat 7 weeks postsurgery showing fracture union.

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