Bony mallet thumb

Surgical treatment of the bony mallet thumb: a case series and literature review

INTRODUCTION

The aim of this study was to provide a more precise statement on the outcome after surgical treatment of a bony mallet thumb and possibly give a treatment recommendation regarding the surgical fixation method.

PATIENTS AND METHODS

All patients (n = 16) who underwent a surgical treatment for an acute bony mallet thumb fracture between January 2006 and July 2019 were enrolled. The surgical method, complications, the range of motion, tip pinch, lateral key pinch, overall grip strength, visual analog score, Disability of the Arm, Shoulder and Hand Score, Mayo Wrist Score, Patient-Rated Wrist Evaluation Score, Buck-Gramcko Score and radiologic parameters were evaluated. Further, a comprehensive literature search on PubMed was conducted covering a period from 1956 to 2021 to include all possible matching articles on the treatment of the bony mallet thumb (n = 21 articles).

RESULTS

Surgical treatment was very inhomogenous including indirect and direct K-wire fixation, screw fixation, plate fixation and anchor fixation methods. The IP joint range of motion and thumb strength ranged from 66 to 94% in comparison to the contralateral side. An open reduction led to worse functional scores compared to a closed reduction. Treatment methods in the literature were also very inhomogenous with a very low patient count, often even pooling data of bony mallet thumb fractures with bony mallet finger fractures. The risk for infection was higher in K-wire fixation methods than in open reduction and internal fixation methods.

CONCLUSION

The evidence for the best treatment of a bony mallet thumb fracture is low. On one hand the functional outcome can be inferior using an open reduction approach, but on the other hand, K-wire fixation methods with a closed reduction approach showed a higher risk for infection. Future multi-center research must be conducted to find the best treatment procedure for the best outcome of the patient.

Management for Bony Mallet Thumb with a Single Extension Blocking Kirschner Wire

Introduction

Mallet finger injury is defined by disruption of the terminal extensor tendon distal-to-distal interphalangeal (DIP) joint. While in the fingers, it is a relatively common injury, it is a rarely encountered entity when involving the thumb. Various conservative and operative treatment strategies have been reported for the management of mallet thumb with no consensus by clinicians.

Case Report

We present the case of a 27-year-old right hand dominant man with a left bony mallet thumb injury that occurred while playing hurling. Hurling is traditional Irish sport that is one of the fastest field games in the world, involving the use of a wooden Hurley and ball. Clinically, there was loss of active extension at the DIP joint of the non-dominant thumb with radiographs revealing an avulsion fracture involving more than one-third of the articular surface at the base of the distal phalanx. Closed reduction and percutaneous fixation using a single extension block Kirschner wire was performed without a transfixion wire across the DIP joint. Four months postoperatively, the patient had regained that good functional dexterity was able to return to playing hurling.

Conclusion

A single K-wire technique may be beneficial with theoretical reduction of chance of iatrogenic nail bed, bone fragment rotation, chondral damage, and bone injury. To the best of our knowledge, no previous reports of its application to bony mallet thumb have been described.

A Bony Mallet Thumb with Interposition of the Nail Plate

Thumb extensor injuries and bony avulsion in the distal phalanx of the thumb are rare compared with other fingers. The most reported complications are infection, nail deformity, joint incongruity, implant failure, recurrent flexion deformity, and residual pain. This report presents a case of 30-year-old man suffering from an injury in the left thumb distal phalanx with a displaced comminuted intra-articular fracture of the distal phalanx of the left thumb. The nail plate was interposed between the dorsal and palmar fragments. The interposition of the nail plate in the bony mallet thumb has not been described before. Surgical treatment and fixation with a 2-mm miniscrew resulted in successful treatment. Clinical suspicion of this complication is of great importance and can affect treatment outcomes.

Hook Plate Technique for Bony Mallet Thumb

Bony mallet is a common sport injury, but bony mallet thumb is rarely encountered. We performed open reduction and fixation of bony mallet thumb using a hook plate procedure on a 27-year-old man under general anesthesia. The patient began working one day after surgery. Six months postoperatively, the patient had excellent dexterity according to Crawford's evaluation criteria and no difficulties at work or playing softball. Tension band fixation, compression pins, and the extension block technique are commonly used to manage bony mallet. Despite the anatomical reduction, rigid fixation, and early resumption of motion skills offered by the hook plate technique, to our knowledge, no previous reports of its application to bony mallet thumb were found. In this case, the hook plate technique was chosen and made an early return to work possible and brought about a successful result.

Mallet Fractures of the Thumb Compared With Mallet Fractures of the Fingers

BACKGROUND

The purpose of this study was to look for differences in mechanism, radiographic findings, and treatment between mallet fractures of the thumb and mallet fractures of the index through small fingers.

METHODS

This retrospective study included 24 mallet fractures of the thumb and 392 mallet fractures of other digits. We compared demographics, injury factors (side, dominant hand, time between injury and first visit, and injury mechanism), subluxation, fragment size, treatment, and time from injury to final evaluation between the 2 groups.

RESULTS

Mallet fractures of the thumb presented for treatment sooner after injury (2.9 vs 13 days on average), had less fragment displacement (27% vs 33%), and less articular involvement (39% vs 46% on average). None of the mallet fractures of the thumb had radiographic evidence of subluxation, whereas 25% of mallet fractures of other fingers had initial or later subluxation.

CONCLUSIONS

Mallet fractures of the thumb are not likely to subluxate.

Two Extension Block Kirschner Wires' Technique for Bony Mallet Thumb

Mallet fingers with an avulsion fracture of the distal phalanx or rupture of the terminal tendon of the extensor mechanism is known as a common injury, while mallet thumb is very rare. In this paper, the case of a 19-year-old woman with a sprained left thumb sustained while playing basketball is presented. Plain radiographs and computed tomography revealed an avulsion fracture involving more than half of the articular surface at the base of the distal phalanx. Closed reduction and percutaneous fixation were performed using the two extension block Kirschner wires' technique under digital block anesthesia. At 4 months postoperatively, the patient had achieved excellent results according to Crawford's evaluation criteria and had no difficulties in working or playing basketball. Various conservative and operative treatment strategies have been reported for management of mallet thumb. We chose the two extension block Kirschner wires' technique to minimize invasion of the extensor mechanism and nail bed and to stabilize the large fracture fragment.