Comparison of functional metacarpal splint and ulnar gutter splint in the treatment of fifth metacarpal neck fractures: a prospective comparative study

Abstract

Background: Fifth metacarpal fractures are the most common fractures of the hand. These fractures are generally treated with conservative methods. The aim of this study was to compare the radiological and clinical outcomes of two conservative treatment methods, functional metacarpal splint(FMS) and ulnar gutter splint(UGS), for the treatment of fifth metacarpal neck fractures.

Methods: A prospective comparative study was designed to assess the conservative treatment of isolated and closed stable fractures of the fifth metacarpal neck. In total, 58 patients were included in the study and were treated with FMS or UGS after fracture reduction in a consecutive order. Angulation, shortening and functional outcome (QuickDASH scores and grip strengths) were evaluated at the 2nd and 6th months.

Results: Forty patients returned for follow-up. Twenty-two patients were treated with FMS, and 18 patients were treated with UGS. The average age was 28 years (SD ± 12, range;18-43) in the FMS group and 30 years (SD ± 14, range;18-58) in the UGS group. After reduction, significant correction was achieved in both groups, but the average angulation was lower in the FMS group(16 ± 7) compared with the UGS group (21 ± 8)(p = 0.043). However, this better initial reduction in FMS group(16 ± 7) could not be maintained in the 1st month follow-up (21 ± 5) (p = 0.009). In the FMS group, the improvement in QuickDASH scores between the 2nd and 6th month follow-up was significant (p = 0.003) but not in the UGS group(p = 0.075). When the expected grip strengths were calculated, the FMS group reached the expected strength values at the 2nd month follow-up, whereas the UGS group still exhibited significantly lower grip strength at the 2nd month follow-up(p = 0.008). However, at the end of the 6th month follow-up, both groups exhibited similar reduction, QuickDASH and grip strength values.

Conclusions: In stable 5th metacarpal neck fractures, FMS is adequate to prevent loss of reduction and yields faster improvement in clinical scores with earlier gain of normal grip strength compared with UGS. However, in the long term, both FMS and UGS methods yield similar radiological and clinical outcomes. Patient comfort and compliance may be better with FMS due to less joint restriction, and these findings should be considered when deciding the treatment method.

Trial registration: ISRCTN79534571 The date of registration: 01/04/2019 Type of study/level of evidence: Therapeutic, II.

Keywords: Angulation; Fifth metacarpal neck fracture; Grip strength; Metacarpal functional splint; Metacarpal shortening; Ulnar gutter splint.

Fig. 1

Ulnar gutter splint

Fig. 2

Functional metacarpal splint

Fig. 3

a Method of Shortening Stipulated (SH – Stip), which is used for the measurement of shortening on AP radiography. A line was drawn through the most distal point of the heads of the neighboring 3th and 4th metacarpals. The shortening was defined as the distance from this line to the most distal point of the fractured fifth metacarpal [16]. b Method of Dorsal Cortex – oblique (DC – 30), which is used for the measurement of angulation at a 30° oblique view. The measurement lines were drawn at the most dorsal part of the metacarpal cortices [16]

Fig. 4

The device used to posture the hand to obtain a standardized 30° oblique view