Boxer s fracture treated by boxers cast vs. k-wire fixation

Received: 29-Jul-2021 Accepted Date: Aug 15, 2021 ; Published: 25-Aug-2021, DOI: 10.37532/1897-2276.2021.16(1).35

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Abstract

Introduction: Despite being one of the most common injuries in orthopaedics, accounting for about 1/10th of all fractures and up to 2/5^th of all hand fractures, the treatment modalities of 5th metacarpal head fractures are controversial in the literature, ranging from conservative management in most cases to minimally invasive surgeries using k-wires and screws.

Material and Methods: This comparative study was carried out by assessing patients with fractures of the neck of the 5^th metacarpal admitted to D Y Patil Medical College, Hospital and Research Centre from July 2020 to March 2021. 20 patients qualified for the inclusion criteria, 10 being in one group and 10 in the other. K-wire fixation was done for the management of the 5^th metacarpal neck fracture in one group while the other group was managed conservatively (boxer’s cast). The groups were classified according to age, sex, mechanism of injury etc. The mean time between getting hospitalized and commencement of surgery (in cases of k wire fixation) was 2 days.

Discussion: The most common age group was found to be 31-40 (80%), with a male predominance of 95%, right to left side ratio of 17:3. On tabulating the data, after three months of follow up, we discovered there was no significant difference in the TAM (total active movement) between the affected and unaffected hand when k-wire fixation was used. There was a certain degree of malrotation in patients treated by conservative management. Overall, cases with a neck-shaft angle of more than 40 degrees seemed to show better results when treated by k-wire fixation but when integrated with patient satisfaction, cases with a neck-shaft angle of fewer than 30 degrees yielded good results when treated by boxer’s cast.

Conclusion: When the neck-shaft angle is greater than 40-45 degrees, k-wire fixation is a better alternative to a boxer’s cast in the treatment of a boxer’s fracture.

Keywords

boxer, fracture, 5^th metacarpal, k wire, cast

Introduction

Despite being one of the most common injuries in orthopaedics [1-3], accounting for about 1/10^th of all fractures and up to 2/5^th of all hand fractures, the treatment modalities of 5^th metacarpal head fractures are controversial in the literature, ranging from conservative management in most cases to minimally invasive surgeries using k-wires and screws. The 5^th metacarpal neck fracture is the most common metacarpal fracture. It is also referred to as boxer’s fracture, brawler’s fracture or bar room fracture [4].

MECHANISM OF INJURY

Boxer’s fractures are an impaction injury caused by axial loading of the 5^th metacarpal caused by a direct punch with a clenched fist on a solid surface. Walls or human faces are frequent solid surfaces, with young adult men (95%) being the most typically afflicted demographic (Figures 1,2).

Figure 1: Mechanism of Injury

Figure 2: Clinical presentation

Fractures of the 4^th and 5^th metacarpals are more common than those of the 2^nd and 3^dd metacarpals because normally, boxers punch with proper form, and the knuckles of the 2^nd and 3^rd metacarpal align linearly with the articulating radius, followed by the humerus, allowing force to travel across joints without injury [5-7].

Patients and Methods

PARTICIPANT DEMOGRAPHICS

This comparative study was carried out by assessing patients with fractures of the neck of the 5th metacarpal admitted to D Y Patil Medical College, Hospital and Research Centre from July 2020 to March 2021. A group of these patients were treated conservatively using a Boxer’s Cast while the others were treated by k-wire fixation. The decision to use cast or k-wire fixation was random without any age/sex/fracture pattern bias and discussed with patients in detail after taking appropriate consent. Randomization was done with each patient picking a card blindly from a decreasing stack of 20 cards, initially consisting of 10 cards labelled ‘K-wire’ and 10 cards labelled ‘Boxer’s Cast’.

INCLUSION CRITERIA

• Age group between 18-50 years

• Unilateral fracture

• Closed fracture

• No history of diabetes, rheumatoid arthritis or gout

• Presenting within 1 week of the injury

EXCLUSION CRITERIA

• Patients with polytrauma, associated fractures of shoulder, elbow wrist

• Patients with severe cardiac and cerebrovascular diseases

• Intra-articular fractures

20 patients qualified for the inclusion criteria, 10 being in one group and 10 in the other. K-wire fixation was done for the management of the 5th metacarpal neck fracture in one group while the other group was managed conservatively (boxer’s cast). The groups were classified according to age, sex, mechanism of injury etc. The mean time between getting hospitalized and commencement of surgery (in cases of k wire fixation) was 2 days.

SURGICAL METHOD/ K-WIRE FIXATION (ANTEGRADE)

• The entry point of the k wire, awl, or drill for the 5^th metacarpal should be dorso-ulnar at the metacarpal base to avoid injury of the carpometacarpal joints, acknowledging the insertion of the extensor carpi ulnaris tendon [8,9]

• It is of utmost importance to make sure the protruding end of the K wire, bone awl, or drill does not get in the way of the gliding extensor tendon

• K-wire is pre-bent

• K wire’s distal tip is bent to around 20 degrees

• The wire is then bent to approximately 10° after about 2 cm

• Fixation with two K wires provides two points of fixation, improving stability and preventing K wire back out from the proximal end (Figures 3,4)

Figure 3: Entry point

Figure 4: Two point fixation with 2 k wires

CONSERVATIVE METHOD/ BOXER’S CAST

• Method of reduction: As collateral ligaments are the only remaining connection to the metacarpal head, they must be tightened to control the distal fragment and accomplish reduction. The Metacarpo Phalangeal (MP) joint is flexed to 90 degrees to cause the MP collateral ligaments to constrict. The flexed metacarpal is oriented dorsally, affecting the reduction of the metacarpal head due to volar angulation correction

• Regardless of the casting procedure chosen, the little and ring fingers must be “buddy taped” (with an intervening layer of cast padding) to prevent fracture malrotation [10] (Figure 5)

Figure 5: Boxer’s Cast

FOLLOW UP

The patients were followed up on postoperative weeks 3, 8 and 12

• TAM (Total Active Movement) was observed at the metacarpophalyngeal and interphalyngeal joints during each follow-up

• Total active movement=total active flexion-total extension deficit

• Pre-op, rotation deformity was noted at the neck-shaft angle, and post-op, the percentage of angular rectification was evaluated and compared to conservative management (Figure 6)

Figure 6: Post op oblique view of right hand on day 0 and day 21 respectively showing considerable neck shaft angle improvement after using boxer’s cast

Results

Results are mentioned in Tables 1-5.

Table 1. Age Distribution

Table 2. Sex Distribution

Table 3. Side

Table 4. Treatment using K-wire fixation

Table 5. Treatment using Boxer’s Cast

Discussion

In our study, 20 patients with a fracture of the neck of the 5^th Metacarpal were assessed at D Y Patil Medical College from July 2020 to March 2021. The most common age group was found to be 31-40 (80%), with a male predominance of 95%, right to left side ratio being 17:3. On tabulating the data, after three months of follow up:

Mean Total Active Movement (TAM) of the affected side was 280 and the mean Total Active Movement (TAM) of the unaffected side was 284 in the case of k-wire fixation.

Mean Total Active Movement (TAM) of the affected side was 263 and the mean Total Active Movement (TAM) of the unaffected side was 286 in the case of the boxer’s cast.

Mean improvement of neck-shaft angle, calculated by the difference of mean pre-op neck-shaft angle (63 degrees) and mean post-op neckshaft angle (20 degrees) was 37 degrees in the case of k-wire fixation.

Mean improvement of neck-shaft angle, calculated by the difference of mean pre-op neck-shaft angle (45 degrees) and mean post-op neckshaft angle (32 degrees) was 13 degrees in the case of boxer’s cast.

Hence, there was no significant difference in the TAM (Total Active Movement) between the affected and unaffected hand and a considerable improvement in neck-s haft angle when k-wire fixation was used.

There was a certain degree of malrotation in patients treated by conservative management. Overall, cases with a neck-shaft angle more than 40 degrees seemed to show better results when treated by k-wire fixation but when integrated with patient satisfaction, cases with a neck-shaft angle less than 30 degrees yielded good results when treated by boxer’s cast.

Limitations

Limitations of this study include patient compliance as one of the patients managed by boxer’s cast was unable to maintain appropriate immobilization by constantly trying to remove the cast every week leading to discrepancies in the ideal result and data for that patient.

Conclusion

Boxer’s fracture or Neck of 5^th Metacarpal fracture is more commonly seen in young male adults. Although most patients prefer the prospect of conservative management, it is associated with a certain degree of malrotation and shortening, especially when the neck-shaft angle is more than 40 degrees. 2-point fixation after using 2 Kirschner wires increases the stability when using a surgical approach. When the neck-shaft angle is greater than 40-45 degrees, k-wire fixation is a better alternative to boxer’s cast in the treatment of boxer’s fracture.

Acknowledgements

This study would not have been possible without the unquestionable commitment and dedication of my colleagues and the undeniable efforts of residents working round the clock.

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