Abstract
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The intramedullary headless compression screw (IMCS) technique represents a reliable alternative to percutaneous Kirschner-wire and plate fixation with minimal complications.
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Transverse fractures of the metacarpal shaft represent a good indication for this technique. Non-comminuted subcapital and short oblique fractures can also be treated with IMCS.
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This technique should not be used in the presence of an open epiphysis, infection and, most of all, in subchondral fractures, because of the lack of purchase for the head of the screw.
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A double screw construct is recommended for comminuted subcapital fractures of the metacarpal to avoid metacarpal shortening. IMCS can even be applied for peri-articular fractures of the proximal third of the phalanx and in some multi-fragmentary proximal and middle phalangeal fractures.
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Usually the intramedullary screws are not removed. The main indications for screw removal are joint protrusion, infection and screw breakage after new fracture.
Cite this article: EFORT Open Rev 2020;5:624-629. DOI: 10.1302/2058-5241.5.190068
Introduction
Several devices and techniques are currently used for the treatment of phalangeal and metacarpal fractures. 1,2 While percutaneous intramedullary Kirschner (K) wires, plate fixation and lag screws exhibit specific advantages and drawbacks, there is still no agreement on the ideal technique to manage these fractures. 1–4 Complications such as stiffness, flexion contractures and extensor lag regularly occur and may require secondary surgery. 3,4
Recent studies 5–12 indicate that intramedullary fixation with headless compression screws (IMCS) is a reliable technique for the treatment of unstable extra-articular fractures of the metacarpals as well as middle and proximal phalanges. Importantly, this treatment is associated with a minimally invasive approach and allows early active mobilization. The screws are left buried beneath the articular surfaces without joint motion interference and the need for removal. In this article, we describe the possible techniques using intramedullary headless compression screws for the treatment of metacarpal and phalangeal fractures.
Metacarpal fractures
Retrograde technique
Transverse fractures of the metacarpal shaft represent a good indication for this technique. Non-comminuted subcapital and short oblique fractures can also be treated with IMCS.
Appropriate screw length and width should be measured on pre-operative imaging. First, a closed reduction is performed. To better reach the head of the metacarpal, the metacarpophalangeal (MCP) joint is flexed to 90°. A 3.0 mm longitudinal incision is made over the MCP joint. A guidewire is inserted along the metacarpal axis under fluoroscopy. The entry point should be on the dorsal part of the metacarpal head for optimal positioning of the screw inside the intramedullary canal. Some authors 5 suggest using a blunt K-wire to avoid cortical penetration. We use headless cannulated compression screws (SpeedTip CCS, Medartis, Basel, Switzerland) and normally insert 3.0 mm screws for the metacarpals.
Jann et al 8 suggested to reach the metacarpal isthmus with the screw to ensure a rigid fixation. To minimize the cartilage injury, we advise the use of 3.0 mm screws even for the fifth metacarpal where the isthmus can measure 5.0 mm. In this case, the relative stabilization will lead to callus formation by means of an elastic fixation. We advise to always go completely beyond the fracture with the screw thread (Fig. 1).
Intramedullary screw fixation of a transverse metacarpal fracture.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Y-strutting technique
In cases with comminuted subcapital or distal shaft fractures of the metacarpal, the use of a single headless compression screw can jeopardize the stability of the construct with subsequent shortening of the metacarpal head. Del Piñal et al 5 proposed the new surgical concept of ‘Y-strutting’ (Fig. 2). Two guidewires are inserted in convergent directions. Then, two screws (3.0 mm and 2.2 mm) are used to create a triangular-shaped frame that supports the bone and prevents a structural collapse. The surgeon should be aware of the potential conflict between the two screws and one screw should be shorter than the other.
Y-strutting technique with two screws for a multi-fragmentary subcapital metacarpal fracture.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Proximal phalanx fractures
Intra-articular technique
The diameter of the intramedullary canal should always be measured before surgery on lateral and antero-posterior radiographs. If the diameter is less than 3.0 mm, we use a 2.2 mm diameter screw.
A 3.0 mm incision is made over the MCP joint. A guide wire is inserted under fluoroscopic control at the dorsal side of the MCP joint, which is bent to 70° of flexion. To facilitate the insertion of the wire, the base of the proximal phalanx is pushed dorsally to provide a dorsal subluxation. A 90° flexion position of the MCP joint can prevent the dorsal displacement of the proximal phalanx because of the tightness of the dorsal capsule and the collateral ligaments. The wire is then advanced into the base of the proximal phalanx along its longitudinal axis. A 3.0 mm or 2.2 mm headless compression screw is then inserted (Fig. 3). The guidewire can also be advanced in the base of the proximal phalanx in an oblique direction without articular violation, particularly if subluxation of the MCP joint is difficult.
Anterograde intra-articular intramedullary headless compression screw (IMCS) fixation of the proximal phalanx. A subluxating force is applied by the surgeon to allow a better entry point at the base of the phalanx.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Anterograde trans-articular technique
When it is impossible to achieve a sufficient dorsal subluxation of the proximal phalanx or the guidewire position is not satisfactory, a trans-articular technique is advised. A 3.0 mm incision is made over the MCP joint which is bent to 90° of flexion. The guidewire is inserted into the dorsal side of the metacarpal head. The wire is then advanced through the metacarpal into the base of the proximal phalanx (Fig. 4). The drawback of this technique is that both the cartilage of the metacarpal head and the base of the proximal phalanx are injured. A cannulated 2.2 mm or 3.0 mm headless compression screw is advanced over the guide wire with a cannulated screwdriver until the screw head is beneath the cartilage of the base of the phalanx.
Trans-articular technique (through the metacarpal head) for an anterograde intramedullary headless compression screw (IMCS) fixation of the proximal phalanx.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Retrograde intra-articular technique
Retrograde headless compression screws may also be introduced through the proximal interphalangeal joint. 5 For this purpose, a 3.0 mm incision is made over the proximal interphalangeal (PIP) joint, which is flexed 90°. The wire is then advanced into the base of the proximal phalanx along its longitudinal axis (Fig. 5). This is an easier and technically faster procedure but creates a larger area of chondral damage of the joint surface of the head of the proximal phalanx compared with the trans-articular procedure. The central slip of the extensor apparatus may also be significantly injured during the insertion of the screw.
Retrograde intramedullary headless compression screw (IMCS) fixation of the proximal phalanx.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Dual anterograde intra-articular fixation
In cases of comminuted extra-articular fractures of the proximal third of the proximal phalanx, the use of a single headless compression screw can result in a less stable construct. As described for comminuted subcapital metacarpal fractures, the ‘Y-strutting’ technique with a dual anterograde fixation (Fig. 6) can be an option to stabilize these fractures as reported by Gaspar et al. 9 A transverse incision is made over the MCP joint which is then flexed to 70°. The proximal end of the phalanx can be subluxated dorsally to facilitate insertion of the first guidewire under fluoroscopy. The first wire can then be inserted in an oblique direction to the long axis of the phalanx. Finally, the second screw is placed in a more oblique orientation and with shorter length. We normally use two 2.2 mm CCS headless compression screws.
Dual anterograde proximal phalanx fixation. Proximal phalanx ‘Y-strutting’.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Middle phalanx fractures
Anterograde extra-articular technique
In cases with transverse fractures of the middle phalanx, the PIP joint is more difficult to sublux. Therefore, we advise the insertion of the guidewire from the ulnar aspect of the base of the middle phalanx in an oblique direction. Subsequently, a 2.2 mm screw is inserted.
Anterograde trans-articular technique
When a good placement of the guidewire cannot be achieved, a trans-articular technique needs to be used. The PIP joint should be flexed to 90° to avoid the risk of fracturing the head of the proximal phalanx during the screw introduction. A guidewire is then introduced into the dorsal aspect of the head of the proximal phalanx with a temporary transfixation of the PIP joint. Then a 2.2 mm screw is inserted.
Retrograde intra-articular technique
A 2.2 mm CCS headless compression screw can be inserted through the distal interphalangeal (DIP) joint using a retrograde technique (Fig. 7). The surgeon must be aware of an extensor tendon injury during this insertion. Furthermore, due to the smaller surface of the DIP joint of the middle phalanx, this technique may result in a greater percentage of damage when compared with the anterograde and trans-articular technique.
Retrograde fixation of the middle phalanx.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
The use of IMCS can be extended even to selected cases of multi-fragmentary extra-articular fractures of the phalanges. The screw should be as long as possible to avoid excessive compression of the fracture site. A trans-articular technique is advised to better place the screw at the centre of the base of the phalanx (Fig. 8). Buddy tape protection is strongly suggested to control the rotational forces on the finger, post-operatively.
Intramedullary fixation of a multi-fragmentary fracture of the middle phalanx. The screw should be as long as possible to avoid compression.
Citation: EFORT Open Reviews 5, 10; 10.1302/2058-5241.5.190068
Post-operative management
After the surgery, the finger is protected with a buddy tape bandage to the adjacent finger to reduce rotational instability. Early active motion is encouraged after the surgery and a removable splint is made for pain control and removed within a week by a hand therapist. The patients are then seen six weeks post-operatively for radiological follow-up to verify fracture union.
Clinical results
Ruchelsman et al 13 examined 20 metacarpal head and neck fractures treated with IMCS. A three-month follow-up of all patients demonstrated full active MCP joint extension and flexion. Mean MCP joint flexion measured 88° (range, 70–100°). No secondary surgeries were performed. All patients achieved radiographic union in six weeks. Two patients had a re-fracture of the metacarpal shaft due to high-energy trauma after consolidation. These patients were treated with screw removal and open reduction and internal fixation with plates.
Jann et al 8 analysed the results of 20 unstable metacarpal fractures treated with IMCS and no immobilization. Seventeen digits in 13 patients had full range of motion, except for one patient with a head fracture of the second metacarpal who had a 25° extension lag. The mean grip strength in all patients was 93% of the contralateral hand. This study did not report any infections, non-union or rotational deformities. No cases of complex regional pain syndrome were reported. One patient underwent screw removal because of proximal migration.
Giesen et al 6 reported their experience with 31 consecutive extra-articular unstable fractures of the proximal or middle phalanges. An intra-articular technique was used in 17 fractures of the proximal phalanx and five fractures of the middle phalanx. A trans-articular technique was adopted in seven fractures of the proximal phalanx and two fractures of the middle phalanx. All fractures healed clinically and radiographically between 28 and 43 days after surgery. At the last follow-up, a mean total active motion (TAM) of 222° (range, 90–295°) was noted. The average extension deficit for the PIP joint was 8° (range, 0–20°).
Gaspar et al 9 described 10 proximal phalanx fractures treated with dual anterograde intra medullary headless screw fixation (IMHS) fixation. At an average follow-up of 84 weeks (range, 61–106 weeks), the TAM was 258° (range, 245–270°) and the mean post-operative QuickDASH score was 3.9 (range, 0–13.6). No complications occurred and no patients required additional surgeries.
Chondral damage
A common point of concern when using intramedullary headless compression screws for the fixation of metacarpal and phalangeal fractures is the potential articular cartilage damage. In general, antegrade fixation from the base of the proximal phalanx produces less damage to the cartilage compared with the retrograde technique. 1,11 Moreover, Borbas et al 7 stated that the loss of cartilage surface in proximal phalanx fractures appears to be less relevant in the intra-articular technique than the trans-articular one, although this difference was not statistically significant. Ten Berg et al 14 reported that the volume of the head of the screws in the metacarpal head has a relatively low relevance (4% for the 2.4 mm screws and 5% of the total joint surface for the 3.0 mm screw). From computed tomography scans of the head of the proximal phalanx, Del Piñal et al 5 reported, instead, a higher articular surface injury by cannulated screws (13% to 18% for a 2.5 mm screw and 19% to 25% for the 3.0 mm screw). At the level of the head of the metacarpal and phalanx there are still no reports of mid-term osteoarthritic degeneration using IMCS.
Tendon injuries
In the study by del Piñal et al, 5 only two patients had an extension lag greater than 30° at the PIP joint. One patient had a concomitant flexor tendon injury. In a cadaveric study, Borbas et al 7 did not find significant damage to the extensor tendons except cases of partial tears < 20% of the width of the tendon.
Screw removal
Usually the intramedullary screws are not removed and can remain inside the bones. However, the main indications for screw removal are joint protrusion, infection, screw fracture after new fracture.
In cases of joint protrusion of the screw, it is possible to perform a small surgical approach at the joint level and easily remove it with a screwdriver. It is also possible to use the guidewire under fluoroscopy to find the screw in cases of a percutaneous procedure.
In cases of screw breakage with a new fracture, it is possible to remove the part of screw nearer to the joint where it was inserted with a small incision and with the help of the guidewire under fluoroscopy.
For the removal of the other part of the screw it is necessary to gain dorsal access through the fracture site especially for metacarpal fractures. Subsequently it is possible to perform a new intramedullary screw fixation, but it is usually advisable to perform an osteosynthesis with a plate due to the risk of further joint damage and screw loosening. Furthermore, in cases of new trauma the screw can be bent. In the case of an acceptable flexion deformity, the screw is left in the bone and the treatment is conservative. In cases with an excessive flexion and rotational deformity, it is necessary to perform a dorsal approach through the fracture site and try to mobilize the screw and remove it through the joint with a second incision.
Giesen et al 6 found a protruding screw in the MCP joint one month after the operation. The screw removal required a mini-open approach to the MCP joint to grasp the protruding part of the screw and remove it.
Complication rate with IMCS, K-wires and plates compared
Stahl and Schwartz 15 reported their experience in 590 K-wire fracture fixations of the hand performed on 236 patients. They found a 15.2% complication rate (osteomyelitis, tendon rupture, nerve lesion, pin tract infection, pin loosening or migration). Fusetti et al 4 reported 32% of complications in 157 metacarpal fractures treated using open reduction and internal fixation with plates, including difficulty with fracture healing (15%), stiffness (10%), plate loosening or breakage (8%), complex regional pain syndrome (two patients) and deep infection (one patient). Jann et al 8 reported results of 20 unstable metacarpal fractures which were surgically managed with compression screws. Out of 15 patients, one required arthrolysis and one had extension lag. Del Piñal et al 5 reported only two patients with a major extension lag at the proximal interphalangeal joint.
Conclusions
Although different fixation methods are described for the treatment of fractures of the hand, surgeons tend to be tempted to use more stable devices with extensive soft tissue damage. This can lead to tendon adhesions, restricted motion, stiffness, and to secondary surgeries. 4 Less invasive procedures, with minor tissue dissection, minimize these complications, but they provide less stability for the fracture. IMCS fixation of the metacarpals and phalanx has been popularized worldwide in recent years due to the minimally invasive approach and to the short learning curve. To date, it is still not clear whether the IMCS can be defined as a rigid fixation or a dynamic one similar to an elastic endomedullary device. However, IMCS may be prone to a rotational instability due to the long lever arm of the finger. This technique should not be used in the presence of an open epiphysis, infection and most of all in subchondral fractures, because of the lack of purchase for the head of the screw.
Overall, IMCS fixation is a reliable technique for the surgical management of transverse and short oblique metacarpal, proximal and middle phalangeal fractures. This intramedullary fixation is not advisable for long oblique fractures and the critical angle at which an oblique fracture becomes unsuitable for IMCS is still under debate. A double-screw construct is recommended for comminuted subcapital fractures of the metacarpal to avoid metacarpal shortening. IMCS can even be applied for peri-articular fractures of the proximal third of the phalanx and in some multi-fragmentary proximal and middle phalangeal fractures.
Open access
This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC BY-NC 4.0) licence (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.
MC reports non-financial support from SOBI, non-financial support from MEDARTIS, non-financial support from SILK BIOMATERIALS, and non-financial support from DYCARE, outside the submitted work.
The other authors have nothing to disclose.
The author or one or more of the authors have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article. In addition, benefits have been or will be directed to a research fund, foundation, educational institution, or other non-profit organization with which one or more of the authors are associated.
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