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

Abstract

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.

Bony Mallet Thumb Treated With the Ishiguro Extension Block Technique: A Case Report

“…Conservative treatment for a bony mallet thumb can also be considered, as demonstrated by some studies [ 4 , 5 ]; however, evidence is lacking. Regarding the surgical treatment for bony mallet injuries, including other fingers, direct pinning, extension block K-wire with direct pinning, compression pins, pullout wires, mini plates, hook plates, mini screws, tension band wiring, K-wire and suture, screw and suture, biodegradable implants [ 6 ], single extension block K-wire [ 7 ], nail plates [ 8 ], and two extension block K-wires [ 9 ], were indicated by previous studies. In the present case, we selected the Ishiguro extension block technique, which is generally used for bony mallet injuries of the other fingers [ 1 ].…”

“…We continued immobilization with a cast for six weeks, considering the strong features of the EPL tendon, as mentioned above. As a new method, we cut the K-wires as short as possible and buried them under the skin, which enabled postoperative casting of the thumb, unlike splinting only in previous studies [ 6 ].…”

“…Osteoarthritic joint changes, delayed bone union, redislocations, joint contractures, nail deformities, skin problems, and infections have been reported as complications of K-wire techniques [ 1 , 6 , 10 ]. Although a higher incidence of local infection using the K-wire technique compared with the open technique has been reported [ 6 ], no infection occurred in the present case. This might have been influenced by the burial of the K-wires and the closure of the skin during the operation.…”

“…Active extension motion is allowed when there is no or only mild tendon injury [ 1 ]. Because open reduction methods can lead to worse functional outcomes of the thumb [ 6 ], closed K-wire methods may be beneficial if infection risk is avoided. In the present case, good postoperative function was achieved by using the Ishiguro extension block technique.…”

Quick and safe: why a k-wire-extension-block-fixation of a bony mallet finger is the favoured treatment

“…While the pathogenesis is clearly understood, there is no consensus regarding the optimal therapy. As a result, there is a debate between conservative therapy with immobilization by solely splinting and minimally invasive interventions [ 13 ]. In addition, open procedures with using a plate have been described [ 14 ].…”