Abstract
Closed multiple metacarpal fractures are uncommon. They are usually associated with significant soft tissue swelling. Early stable fixation and functional rehabilitation optimises outcome. We present a review of 19 patients with 43 metacarpal fractures treated by early open reduction and internal fixation with 2 mm plates. Eighteen patients recovered a full range of motion, while one patient was lost to follow-up. Implant removal on account of extensor irritation was required in only two metacarpals in two patients. Plating of multiple closed metacarpal fractures is a safe, reliable and consistently reproducible treatment method.
Closed metacarpal fractures are common fractures, especially in young and active patients. The majority are stable and can be treated successfully by non-operative methods (Stern, 1999; Tavassoli et al., 2005). Indications for open reduction and internal fixation of metacarpal fractures are well described (Amadio, 1991; Stern, 1999). Operative treatment of solitary metacarpal fractures is reserved for displaced fractures with significant shortening, rotation or both. There are no scientific guidelines for the amount of acceptable shortening in isolated fractures, and varying amounts have been recommended (Freeland et al., 1986; Gropper and Bowen, 1984; Lumplesch et al., 1985). Closed multiple metacarpal fractures are considered highly unstable and require stable fixation. It is well recognised that early stable fixation of open metacarpal fractures is necessary, to allow early rehabilitation in an effort to improve final outcome (Mudgal and Jupiter, 2006). As techniques of internal fixation of fractures in the hand have evolved over the last four decades, there has been increased enthusiasm for internal fixation of these fractures. While there have been several encouraging reports on internal fixation of metacarpal fractures (Dabezies and Schutte, 1986; Hastings, 1987), other authors have reported less than optimal outcomes with a large number of complications (Fusetti et al., 2002; Page and Stern, 1998; Stern et al., 1987).
The aim of this retrospective study was to determine whether plate fixation using contemporary techniques and principles can be associated with satisfactory outcomes in a consistent and reproducible manner and to highlight some common features of closed, multiple metacarpal fractures.
PATIENTS AND METHODS
A retrospective review of all medical records of patients with a diagnosis of closed ipsilateral multiple metacarpal fractures was conducted with the approval of our Institutional Review Board. Between April 1999 and December 2005, 43 closed, displaced and/or angulated multiple metacarpal fractures in 19 patients were treated with open reduction and internal fixation (Figs 1 and 2). There were 17 men and two women with a mean age of 24 (range 14–40) years. The right hand was involved in 16 patients (all dominant) and the left hand in three (all non-dominant). The initial injury was the result of a punch in nine patients, a fall from standing height in one patient, a fall from greater height in one and a fall from a bicycle in two other patients. Two patients had a sports-related injury and four patients were involved in a motor vehicle accident. Three hand surgeons plated 40 of the 43 metacarpal fractures at an average of 8 (range 0–25) days after the injury. The other three metacarpal fractures were treated with open reduction and inter-fragmentary lag screw fixation only. One patient had ancillary fixation using a K-wire. Patients with open wounds and any other ipsilateral upper limb injury were excluded from the study.
The ring finger metacarpal was most commonly fractured (n = 15), followed by the little finger metacarpal (n = 13). The combination of ring and little metacarpal fractures was seen in ten patients, of which seven displayed a transverse fracture pattern (Fig 1). Five patients had three metacarpal fractures, of which four involved the middle, ring and little metacarpals. Features common to all of these four fractures were a spiral fracture pattern combined with a fracture involving the distal neck and shaft of the little metacarpal (Fig 2). All fractures were displaced and angulated. Ten shaft fractures were noted to be comminuted on pre-operative radiographs. At surgery, a further 20 fractures were noted to display (pre-operatively undiagnosed) undisplaced fracture lines. In all patients with fractures involving the index or middle metacarpal, comminution was noted in at least one of the fractures. Two of the 43 fractures were intraarticular; one patient had a fracture extending into the index finger metacarpophalangeal joint as well as a fracture extending into the little finger carpometacarpal joint.
Surgical technique
The metacarpal fractures were exposed through incisions made in the space between the involved metacarpals. When three metacarpals were fractured, two incisions were used. All fractures were fixed with implants from the Modular Hand Set (Synthes, Paoli, PA, USA). Thirty-three fractures were fixed using a 2.0 mm standard plate or a limited contact dynamic compression plate with a minimum of two screws on each side of the fracture. Four fractures were fixed with 1.5 mm plates and three fractures were fixed with 2.4 mm plates. Interfragmentary lag screws alone were placed in three fractures (Figs 3 and 4).
Postoperatively, patients were immobilised for 3 to 5 days, then mobilised by active and active-assisted range of motion exercises. Strengthening was instituted after 3 to 4 weeks. Final evaluation was carried out by the treating physician at a minimum of 2 months after surgical fixation. Patients were evaluated radiographically until bony union was confirmed.
RESULTS
Fourteen patients were evaluated at an average of 6 (range 2–28) months after injury. Four patients had returned to normal function without complaints after 2 months and declined further follow-up. There were no immediate postoperative complications. Eighteen of the 19 patients recovered full function (TAM>230°) within 2 months and returned to their original jobs (Fig 5). One patient was lost to follow-up after 2 weeks. Complications were experienced during follow-up in four of the 19 patients.
Complications related to the plates were encountered in two patients. One patient had symptoms of extensor tenosynovitis at the base of the middle metacarpal that required removal of the 2.0 mm T-plate 5 months after the original surgery; this led to complete symptom resolution. In the second patient a 2.0 mm condylar plate, which was utilised to fix a little metacarpal fracture, caused painful limitation of the last 30° of metacarpophalangeal joint flexion, in addition to causing tenderness over the distal end of the plate. Removal of this plate 4 months after the original surgery led to resolution of local tenderness and recovery of metacarpophalangeal joint flexion.
There was one asymptomatic, delayed union of a little metacarpal fracture. This patient, who was a heavy smoker, had sustained combined ring and little metacarpal fractures, which were treated with a six-hole 2.4 mm plate with three screws on each side of the little metacarpal fracture. Union of the fracture occurred 9 months after initial treatment without any further intervention.
The only patient who had ancillary fixation with a K-wire at the base of the little metacarpal developed persistent tenderness at this site, but had a full range of motion. Complete symptom resolution was noted after removal of this K-wire, 7 months after the original surgery.
DISCUSSION
Closed multiple metacarpal fractures are uncommon. They are usually the result of a high-energy injury, although the majority of cases in this series occurred with low-energy trauma. While most fractures occur on the ulnar side of the hand, it is not uncommon to see fractures of three or more metacarpals, which include the middle as well as index metacarpals. In our study we did not encounter any patient with fractures of four or five metacarpals.
Plate fixation in closed multiple metacarpal fractures is necessary for several reasons. Firstly, metacarpal length is very likely to be reduced in multiple metacarpal fractures (Eglseder et al., 1997; Meunier et al., 2004). This is more evident when a border metacarpal is involved, as it cannot rely on the adjoining metacarpals to hold it out to length. Definite guidelines for acceptable metacarpal shortening are lacking. However, it is recognised that shortening as well as loss of the transverse arch, which result from multiple displaced metacarpal fractures, are factors that can compromise normal hand function by altering interosseous muscle anatomy and flexion and extension force ratios, both of which can lead to an asynchronous, non-integrated grasp resulting in reduced grip strength (Freeland and Orbay, 2006; Kozin et al., 1999; Low et al., 1995; Meunier et al., 2004; Strauch et al., 1998).
Furthermore, closed ipsilateral multiple metacarpal fractures are frequently associated with severe soft tissue swelling that can lead to intrinsic muscle scarring and tightness, which may impair final hand function (Smith, 1974). The advantage of the dissection required for plate fixation is that it decompresses the interosseous compartments. Finally, early rigid plate fixation allows early mobilisation, which is essential for muscle excursion and nutrition, to overcome post-traumatic atony and maximise functional outcome.
Several authors have noted a large number of satisfactory outcomes after plate fixation of metacarpal fractures (Dabezies and Schutte, 1986; Ford et al., 1987; Hastings, 1987). Other authors have noted complication rates of up to 35% with plate fixation (Fusetti et al., 2002; Page and Stern, 1998; Stern et al., 1987). These studies must be interpreted cautiously as they include open and closed fractures, single and multiple fractures, combinations of metacarpal and phalangeal fractures and the use of implants not designed specifically for use in the hand. Fusetti et al. (2002) are the only authors to report a series of multiple metacarpal fractures (19 patients) similar to ours and they speculated that the higher incidence of complications in their series of patients with multiple metacarpal fractures was related to the higher-energy trauma sustained by these patients.
Our data show that good outcome can be expected after plate fixation in closed multiple metacarpal fractures utilising hardware specifically designed for use in the hand, provided the principles of internal fixation in the hand are followed. Eighteen patients had an excellent functional result (TAM of >230°) at final follow-up. Only two patients required plate removal because of interference with tendon excursion or adjacent joint function. We agree with Hastings (1987) and Stern (2000) in that we think that the poor results published on plate fixation are not related to the plates, but stem from inappropriate patient selection, failure to apply biomechanical principles, faulty technique, poor soft tissue handling and inadequate functional aftercare.
Our data reveal several interesting characteristics about these fractures, their assessment and techniques of fixation. A combination of ring and little metacarpal fractures is very common and these fractures commonly display a transverse fracture pattern. When the fractures involve the index or middle metacarpals, spiral fractures are much commoner. We speculate that this change in fracture characteristic is related at least in part to the relative immobility of the index and middle carpometacarpal joints. It is well recognised that the ring and little carpometacarpal joints have significantly greater motion than the middle one. It appears that this greater degree of motion may influence the fracture pattern. When fractures of multiple metacarpals include either the index or middle metacarpal, comminution is also commoner. Routine radiographs often do not reveal the entire extent of fracture geometry and several occult fracture lines may be noted during surgery. It is therefore prudent for the surgeon to be able to apply alternative fixation constructs as needed. When faced with three metacarpal fractures, all fractures do not necessarily need to be plated. It is not uncommon for at least one fracture to be amenable to interfragmentary screw fixation alone. Stable fixation can be achieved consistently with 2 mm implants, which need to be carefully contoured and can be customised as needed. In metaphyseal bone, 2.4 mm screws can be placed through 2 mm plates as “escape” screws, in case satisfactory purchase is not obtained by 2 mm screws. A minimum of four cortices of fixation on either side of the fracture appears to be essential in order to avoid any implant failure. Finally, it is imperative that adequate soft tissue closure is achieved over the plate so as to avoid extensor tendon irritation. Early rehabilitation helps to maximise functional restoration.
Although this study has several limitations, including the retrospective design and the limited number of patients, our data confirm that plate fixation in closed multiple metacarpal fractures is a safe and reliable method of treatment, which is capable of providing consistently reproducible and predictably good outcomes. Routine removal of plates is unnecessary.