Late Isolated Comminuted Trapezium Fracture with Carpometacarpal Subluxation

A Case Report

Abstract

Trapezium fracture is the third most commonly occurring fracture in carpal bones, in most author series, but isolated and severely comminuted fracture with carpometacarpal subluxation is extremely rare. We report a case of a 24-year-old man who sustained a closed comminuted trapezium fracture on his left hand, with trapezio-metacarpal subluxation, presented 3 weeks after injury. He was treated by open reduction and fixation by two mini screws and provisional stabilisation of first carpometacarpal joint by two Kirshner wires. Satisfactory outcome was achieved at 6-month follow-up.

INTRODUCTION

Isolated fractures of trapezium are rare with incidence of 1–5% and usually are difficult to detect and often missed clinically in standard radiograph.[¹²³] Therefore, it is necessary to increase our clinical suspicion to think beyond sprain to diagnose early and treat accordingly in order to restore articular congruity for optimum thumb functioning.

There are two main mechanisms of injury. One is indirect axial loading and the other is direct impaction. Indirect injury is the result of a fall on an outstretched thumb, causing the thumb to be driven axially hitting the trapezium. This commonly causes a vertical fracture through the body of the trapezium, with other less common variants depending upon the vector of the force, including comminuted fracture.[⁴]

There is no consensus in the literature about the ideal method of treatment but it is a matter of scientific debate and clinical discussion to identify the best method of treatment in individual scenarios. Generally, an unstable intra-articular fracture warrants open reduction and internal fixation as a preferred method to restore the joint congruity, and an additional stabilisation to prevent the subluxation and safeguard the fixation.

We report the case of a 24-year-old man who sustained a closed comminuted trapezium fracture on his left hand, with trapezio-metacarpal subluxation, presented 3 weeks after injury.

CASE REPORT

A 24-year-old man presented to us with pain and swelling over the left thumb base. He could barely move his left thumb. He had a history of fall 23 days earlier on his outstretched thumb and used home remedy regarded as sprain. We immediately ordered an X-ray of his left thumb with antero-posterior and lateral views along with the Robert view as we had a suspicion that he might have injured his first carpometacarpal (CMC) joint. The X-ray revealed comminuted trapezium fracture with dorso-radial subluxation of the first CMC joint of his left thumb [Figure 1]A. We ordered a computerised tomography (CT) scan to make out the fracture pattern more accurately [Figure 1]B. After assessing the CT scan which helped us to determine the large fragments and to plan the trajectory of the screws, we decided to reduce and fix the fracture by open method.

Figure 1: Plain radiograph of patient showing comminuted fracture of trapezium with carpometacarpal subluxation (A). CT scan of the same patient showing extent of comminution of trapezium

SURGICAL TECHNIQUE

The fracture site was opened by a dorso-radial approach under brachial block with tourniquet control keeping the left upper limb over a side table while the patient lay in supine position. After exploration, we isolated the bigger fragments from dorsal aspect while gently maintaining axial traction to thumb, removing the deforming force as much as possible. We could successfully reconstruct the articular surface by meticulous handling of fragments without disturbing the soft tissue attachments. Reduced fragments were fixed by two 2 mm mini screws with adequate purchase. The thumb was maintained in reduced position by two 1 mm Kirshner wires transfixing the first CMC joint and applied a thumb Spica slab for 3 weeks. Immediate postoperative radiograph showed satisfactory reduction and fixation [Figure 2]A.

Figure 2: Plain radiographs of patient showing reduction and fixation of fracture subluxation of trapezium at immediate postoperation day (A) and at 6-month follow-up (B)

FOLLOW-UP

After 3 weeks the wires were removed and mobilisation began under supervision. Within 2 months’ post surgery, the patient’s Kapandji score increased from 2 to 8. After about 6 months of follow-up, the fracture united and the first CMC joint was well maintained [Figure 2]B. By this time, the patient regained painless near-normal movement at the first CMC joint with a Kaplan score of 10 and adequate pinch strength. Although grasp was comparable with his right thumb, power grip had slowest recovery.

DISCUSSION

Isolated trapezium fracture is a rare entity and when it is comminuted and a few weeks old, it becomes extremely difficult to treat and regain the normal thumb movement. When trapezial fractures occur in isolation, they have been shown to have two common fracture patterns: longitudinal vertical or a comminuted crush.[⁵] Two common mechanisms of injury according to Pointu et al.[⁴] are first due to fall onto the hand with the wrist extended and the hand in radial deviation and secondly due to direct commissural trauma combined with varying degrees of shearing.

Plain radiograph of the thumb in orthogonal view is usually sufficient to detect a trapezium fracture unless it is undisplaced. Often a CT scan is useful to detect it if there is clinical suspicion. In case of comminution and carpometacarpal subluxation, a CT scan gives adequate information of the fragmentation to plan the surgical strategy prior to execution.

Most of the literature recommends open reduction and internal fixation for displaced intra-articular fractures of the trapezium as in this case.[⁵⁶] Cordrey and Ferrer-Torrells[⁵] were the first to recommend this. Foster and Hastings recommended either open reduction and internal fixation or closed reduction and pinning.[⁷]

Inston et al.[⁸] described the use of a Herbert screw. Tolat and Jones[⁹] reported a case of a trapezium fracture with associated CMC dislocation suggesting that accurate reduction and fixation of the trapezium may be enough to stabilise the trapezio-metacarpal joint. Arthroscopic assisted fixation of this injury was reported with successful outcome.[¹⁰]

CONCLUSION

We have reported this rare case of isolated trapezium fracture which was comminuted and 3 weeks old. There was a subluxation of the first CMC as well. Considering the fracture pattern and delay of treatment, open reduction and internal fixation was carried out to recreate the joint surface and achieve the joint congruity. The fixation was offloaded by two intra-articular k wires.

An isolated and comminuted trapezium fracture needs adequate imaging in terms of CT scan with 2D and 3D reconstruction. It helps us to understand the fragmentation to plan the surgical strategy and implantation in order to achieve the best possible reduction of the first CMC joint. Proper planning and meticulous reduction with adequate fixation with mini screws can give a near-normal outcome in terms of thumb movement.

DECLARATION OF PATIENT CONSENT

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

FINANCIAL SUPPORT AND SPONSORSHIP

Not applicable.

CONFLICTS OF INTEREST

There are no conflicts of interest.

Acknowledgement

This manuscript represents the honest work performed at Bhattacharyya Orthopaedics and Related Recovery Centre, Kolkata, India. The authors of this scientific article express due gratitude for the full support they received from the administration of this hospital to carry out this work.