gms | German Medical Science

Objectives/Interrogation: Extension block pinning for acute mallet fractures have been reported with good results. However, for chronic cases, various methods have been proposed. We evaluate the clinical outcome of mallet fractures treated with bone suture anchor for mallet fracture.

Methods: We evaluated 11 cases of mallet fracture patients treated with bone suture anchor (JuggerKnot® Soft Anchor Mini 1.0 mm, ZIMMER BIOMET) that were observable for more than 3 months after surgery (8 men and 3 women; mean age, 42 years). The affected fingers were 6 middle fingers, 1 ring finger and 4 little fingers. Two cases were chronic nonunion of mallet fracture after extension block pinning surgery failed. The surgical approach was follow; the dorsal side of the DIP joint was incised and the bone fragment was released with the extensor tendon and JuggerKnot® was inserted to the distal phalanx after making the fracture site sufficiently fresh. The terminal tendon was sutured with the bone fragment reduced. Arthrodesis of distal interphalangeal joint was added with a Kirschner wire inserted from finger apex. The Kirschner wire buried subcutaneously and was removed on 6 weeks after surgery. We examined the degree of flexion, extension lag, and bone union at the final follow-up. Moreover, we compared the results between the cases that undergone surgery within a month from injury and more than a month.

Results and Conclusions: The mean degree of flexion was 53 ° (30-75 °), and the extension lag was 7.3 ° (0-20 °). Two patients showed excellent, 3 showed good and 6 showed fair results on the Crawford's score scale. Radiographic bone unions were not achieved in two cases but no loss of reduction. In the comparative study between the two groups, 5 cases into group A (the average period from injury to surgery was 6.4 (0-17) days), and 6 cases into Group C (the average was 51 (31-88) days). The average flexion of the group A was 57 ° (40-75 °), and extension lag was 7.4 ° (2-20 °). The group C was 50 ° (30-70 °) and 7.1 (0-15 °), respectively. There is no significant difference between the two groups.

The necessity of joint fixation has been suggested from fixation strength of anchor and it was useful to primary arthrodesis with Kirschner wire because it can be washed hands immediately after the removal of stitches. In this study, this method using bone suture anchor was able to obtained good results in both acute and chronic cases. This procedure was considered to be one of widely applicable methods for mallet fracture.