When a volar locking plate is not the right choice in fractures of the distal radius: Case based technical considerations

Abstract

A volar approach is commonly used for fixation of distal radius fractures with a volar locking plate. There are certain fracture patterns for which volar locked plating is not suitable. This case based review outlines such case examples.

1. Introduction

Distal radius fracture is one of the most common injuries of the musculoskeletal system. It can result from a simple fall in the elderly or a higher energy mechanism in younger patients. There are multiple treatment options ranging from non-operative management, closed reduction and pinning, closed reduction and external-fixator application, and open reduction with internal fixation. In the contemporary setting, open reduction and volar locking plate fixation has become the preferred treatment for most of these fractures.¹ Monoblock volar locking plates remain the popular methodology for treatment for extra-articular bending fractures with comminution in the young person as well as in the elderly fractures with intra-articular extension that are multi-fragmentary. Volar marginal fractures are also best fixed with volar fixed angle implants. However when utilized appropriately, these implants must be placed proximal to the watershed line in an effort to avoid undue prominence of the implant volarly, and subsequent irritation of the flexor tendons. Not uncommonly, the surgeon will be faced with fracture patterns, which involve small fragments or very distal fragments, for which a volar locking plate is not the right choice. In these situations the surgeon must be familiar with using fixation tools that respect fragment geometry and fragment size, and should also be prepared to stabilize the radius in a columnar or a fragment specific fashion.

This review outlines case examples of distal radius fractures where alternate approaches and fixation methods other than volar locked plating are more suitable.

2. Important anatomic features

In deciding fragment specific fixation or columnar fixation, it is important to remember the anatomical features of the distal radius which are unique and which lend themselves to understanding fragment geometry, fragment size and implant orientation.

• 1.The radial styloid which is part of the radial column, extends volar, radial and distal to the radial platform. When the distal radius is viewed end on, it is noted that the tip of the radial styloid lies volar to the equator of the distal radius articular surface. Therefore, any implant placed from the tip of the radial styloid should be directed not only ulnarly but also dorsally to gain adequate purchase in the proximal fragment.
• 2.It is also important to remember that the radio-scapho-capitate ligament is attached about 7 mm from the tip of the radial styloid to the volar lip of the radius. Displacement of the radial styloid inevitably leads to displacement of the carpus due to this important radiocarpal ligament.
• 3.The volar lunate facet which comprises the volar half of the intermediate column, extends volarly, ulnarly and distally. The short radio-lunate ligament is attached to this fragment. Displacement of this fragment invariably leads to displacement of the carpus as well, due to the aforementioned radiocarpal ligamentous attachment.
• 4.The volar rim of the distal radius between these 2 important ligaments outlined above, is most commonly the area of propagation of large fragment fracture lines and the surgeon should familiarize themselves with these very predictable fracture patterns.
• 5.The dorsal ulnar corner of the intermediate fragment-the die punch fragment,² also bears attachment of the dorsal radio-triquetral ligament. Just radial to this fragment is another area where there is no prominent ligamentous attachment.
• 6.Areas of the distal radius articular margin whether volar or dorsal, when anatomically located in the immediate vicinity of these large ligaments, remain the vulnerable zones for fracture line propagation. This important anatomical feature which contributes to fracture line generation, has been noted by Mandziak and colleagues.³

3. Radiographic assessment

Our standard protocol for analysis of these fractures includes postero-anterior (PA), oblique, and lateral radiographs done prior to fracture reduction and similar views done after reduction. We have no hesitation in obtaining a computerized tomography (CT) scan in these uncommon fracture patterns. Based on our analysis of the radiographs as well as the CT scans we pay particular attention to:

• 1.Fragment size and geometry as well as location, which will decide implant placement, size and direction.
• 2.Particular attention is given to volar marginal rim fractures especially the volar lunate facet, dorsal rim fractures, radial styloid fractures as well as any element of articular depression.

4. Indications

In our opinion, volar locked plating is not considered suitable for the following injury patterns:

• 1.Radiocarpal fracture dislocations
• 2.Dorsal Rim fractures
• 3.Scaphoid Impression Fractures
• 4.Isolated lunate facet fractures

4.1. Case 1

A 30-year-old made was involved in a motorcycle accident and presented with a left distal radius fracture. PA (Fig. 1a) and lateral radiographs (Fig. 1b) reveal a complex radio carpal fracture dislocation of his left wrist. Computed tomography (CT) images were obtained after closed reduction (Fig. 2). A radial styloid fracture is seen with a horizontal fracture line involving almost the entire scaphoid fossa (Fig. 2a). Sagittal CT views demonstrate a dorsal rim fracture of the distal radius with impaction (Fig. 2b). Also seen is a small volar lip fracture (Fig. 2b). All fragments are small and distal to the watershed line. Therefore, a monoblock volar locking plate would not be the right choice in this fracture pattern.

Fig. 1.

PA (1a) and Lateral (1b) radiographs show a radiocarpal fracture dislocation with a radial styloid fragment and dorsal rim fracture fragments.

Fig. 2.

Coronal (2a) and Sagittal CT (2b) show a radial styloid fragment with horizontal fracture line. Dorsal rim fracture fragment with impaction. Seen dorsal to that are small fragments representing capsular avulsion.

Radiocarpal fracture-dislocations are complex injuries characterized by dislocation of the radiocarpal joint (Fig. 1). They are typically associated with a small cortical rim and/or radial styloid fracture (Fig. 2). Dumontier et al.⁴ proposed a classification system for radiocarpal dislocations. Type 1 are very rare and primarily ligamentous injuries. Type 2 radiocarpal dislocations are associated with fractures of the radial styloid that involves more than 1/3rd of the width of scaphoid fossa and may continue to the dorsal margin of distal radius. The authors recommended repair of the volar ligamentous structures for type 1 injuries and a dorsal approach with fixation of the radial styloid fragment for type 2 injuries. Other authors have recommended a combined volar as well as a dorsal approach for volar ligamentous repair or fixation of small volar avulsion fracture in radiocarpal dislocations with dorsal shear fractures.^5,6

In the case presented above, a combined approach was utilized. A standard dorsal approach to the wrist was used with a longitudinal incision over distal radius and radiocarpal joint in line with the 3rd metacarpal. The extensor pollicis longus tendon was mobilized from the 3rd dorsal compartment and the tendons of the second and fourth dorsal compartment were retracted to gain exposure. The dorsal small rim and the radial styloid fractures are clearly visualized (Fig. 3). The dorsal capsule may be torn (Fig. 3), but if it is intact, a limited dorsal arthrotomy may be made parallel to the dorsal rim to inspect the articular surface and look for any suspected carpal or ligamentous injury. At this point, the radius fracture is reduced and fixation is started with the less comminuted fracture fragment. In this case, a 1.6 mm smooth Kirschner wire was used for provisional fixation of the radial styloid fracture and articular reduction was also confirmed using intraoperative fluoroscopy (Fig. 4). Dorsal rim fragments were dis-impacted, the articular surface restored under direct vision and then the defect was filled with cancellous allograft bone chips (Fig. 4). A low profile dorsal distal radius columnar plate was then carefully contoured and placed in a buttress mode for the dorsal rim fragments (Fig. 4).

Fig. 3.

Radial styloid and dorsal rim fracture fragments are clearly visualized. Periosteum and capsule has been stripped from the injury itself. Hand is to the right and forearm to the left in this image.

Fig. 4.

Hand is to the right and forearm to the left. Fixation was started by obtaining provisional fixation of radial styloid fragment with a Kirschner wire. Dorsal rim fragment was dis-impacted, reduced and then held with a carefully contoured fragment specific dorsal plate.

An extended carpal tunnel approach was made volarly and dissection was performed between the ulnar neurovascular bundle and flexor tendons. The wrist capsule was identified volarly along with the volar lip fragments with attached ligaments. These volar lip fragments were reduced and held in place with a tension band construct around the volar wrist ligaments and held in place over a 3.5 mm screw as a post in the radius (Fig. 5). Additional fixation was achieved for the radial column by utilizing a 3.0 mm headed cannulated screw and an additional radial column plate (Fig. 5). The radial column plate is placed in the bare area between the 1st and 2nd dorsal compartments. Stability of the construct was then tested under fluoroscopy and radiocarpal joint was noted to be stable, concentric and congruous under dynamic fluoroscopy with wrist range of motion. Careful repair of the periosteal sleeve and capsule layer was performed to prevent irritation of tendons from the hardware.

Fig. 5.

PA (5a) and Lateral (5b) views show fragment specific fixation. Radial column fixation has been achieved using a cannulated screw and a radial column plate. Dorsal rim fragment fixation has been achieved with a buttress plate and supported with cancellous bone chips after dis-impaction. Volar lip fragments have been restored by a tension band construct.

Alternatively, in fractures where the dorsal rim fragments are very small, fixation may be started volarly. Through the extended carpal tunnel release approach, the volar rim fragments may be fixed and by dissecting subcutaneously across to the radial styloid, the radial styloid may also be fixed using the techniques outlined above. After getting satisfactory stabilization and fixation, the stability of the radiocarpal joint may be tested. It is not uncommon in patients with very small dorsal rim fractures, for the construct and the radiocarpal joint to be stable at this point. In such situations, it is the practice of the senior author (CSM) to not proceed with dorsal fixation on a routine basis.

Many plates are available for these fractures. The most recently designed plates have variable angle locking screws. The dorsal plate if utilized, should be applied as distally as possible. These plates need careful contouring to fit the distal radius metaphysis and the radial styloid. Many different fixation options can be successfully implemented as long as principles of fragment specific fixation are followed. Fig. 6 shows another case example of a patient who sustained radiocarpal fracture dislocation, where a combination of suture anchors, K-wires and cannulated screw was used to obtain stable fixation. When last seen 6 months post-operatively, the patient was noted to have a good functional outcome. (Fig. 7).

Fig. 6.

Lateral and PA radiographs after fixation of a radiocarpal fracture dislocation. Bottom views show radiographs after Kirschner wire removal and healing. Two suture anchors were used volarly to obtain fixation of volar radiocarpal ligaments. 1.6mm Kirschner wires were used dorsally to obtain fixation of dorsal rim fragments. Headed cannulated screw (3.0 mm) was used for fixation of the radial column.

Fig. 7.

Excellent forearm rotation and slightly diminished wrist flexion-extension arc obtained at 6 months for a patient who sustained radiocarpal fracture dislocation.

4.2. Case 2

This 64 year old female fell on the outstretched hand and sustained a comminuted intra-articular distal radius fracture with a dorsal shear pattern (Fig. 8). Pre-operative evaluation with CT shows a separate styloid fragment and a dorsal shear fragment with dorsal subluxation of carpus (Fig. 9). The volar cortex is completely intact and the entire fracture is dorsal. This combination of fracture fragments and geometry is largely predictable based on the anatomical features outlined before. A volar locking plate would not address this fracture pattern suitably. A standard dorsal approach was utilized. A carefully contoured dorsal buttress plate was used to neutralize the shear component and a separate cannulated screw was used for the styloid fragment (Fig. 10). When last seen 9 months post-operatively, the patient was noted to have an excellent functional outcome (Fig. 11).

Fig. 8.

Dorsal shear fracture of distal radius with dorsal subluxation of carpus.

Fig. 9.

Sagittal, Coronal and 3D CT showing a dorsal shear fracture pattern with dorsal subluxation of carpus. Volar cortex is mostly intact.

Fig. 10.

Fragment specific fixation using a buttress plate for the dorsal shear component and a cannulated screw for the styloid fragment.

Fig. 11.

Excellent functional outcome obtained at 9 month follow up.

Lozano-Calderon et al., described 20 patients with dorsal shear fractures associated with dorsal radiocarpal subluxation or dislocation.⁷ Typically, these fractures involved large dorsal shear fragments similar to that in case 2 and often involved impaction of the articular surface. These authors recommended a dorsal approach to buttress the dorsal shear fractures and reconstruct the articular surface for associated central impaction.

4.3. Case 3

A 27 year old male sustained an intra-articular distal radius fracture with a small radial fragment and joint incongruity/depression noted on radiographs (Fig. 12). A CT scan showed articular depression with an additional dorsal rim fragment (Fig. 13). Once again the volar cortex is completely intact.

Fig. 12.

PA and Lateral radiographs show articular incongruity and comminution of the radial column.

Fig. 13.

Sagittal and 3D CT show a scaphoid impression fracture with articular depression and dorsal rim fragments.

This fracture pattern is called a scaphoid impression fracture. These fractures are caused by the scaphoid being driven into the distal radial articular surface. Depending on the degree of radial or ulnar deviation at the moment of impact, the scaphoid impression created on the distal radius articular surface can be similar to the size of the proximal pole or the proximal half of the scaphoid body. Typically, these fractures involve a dorsal cortical break as well as a radial styloid fracture.^3,8

The dorsal cortical break can be utilized to approach the articular depression, which is then elevated and bone grafted prior to fixation. In this case a dorsal approach was performed. The dorsal rim fragment was elevated distally based on its attachment to the dorsal capsule. This window was then utilized to elevate the depressed articular fragment and supported with cancellous bone chips. The dorsal rim fragment was then placed back into its bed, fixed to the shaft of radius and articular fragment using a well contoured dorsal plate (Fig. 14). Additional K-wire fixation was performed for the small radial column fragments.

Fig. 14.

Well contoured dorsal plate to achieve fixation of the dorsal rim to the shaft and buttresses dorsal rim to the articular fragment after it has been elevated to restore the joint surface. Additional Kirschner wire fixation of radial column comminution is also demonstrated.

Fig. 15 shows another example of a scaphoid impression fracture. The volar cortex is intact and fracture lines exit dorsally. A dorsal approach was utilized. Joint congruity was restored under direct visualization. A dorsal plate was carefully contoured and variable angle locking screws were placed distally to function as rafting screws for the elevated fragment (Fig. 16).

Fig. 15.

PA radiograph (15a) showing a scaphoid impression fracture with joint incongruity. Sagittal CT and 3D formatting (15b,c) show articular depression with fracture of the dorsal rim and comminution of radial styloid.

Fig. 16.

PA view (16a) showing restoration of joint congruity. Dorsal plate contoured to radius metaphysis achieving fixation of the dorsal rim to shaft. Locking screws are placed through the plate distally to function as rafting screws for the depressed articular fragment (16b).

4.4. Case 4

This 72 year old male patient sustained an isolated lunate facet fracture. The PA radiograph (17a) shows an isolated lunate facet fracture and the lateral radiograph shows an increased tear drop angle (17b). This teardrop angle is best assessed on a true lateral radiograph of the wrist. It is calculated as the angle between the axis of the volar lunate facet and the central axis of the distal radial shaft. This angle usually measures 65–70°. An increased teardrop angle usually signifies a volar marginal shearing injury involving the intermediate column, which is represented by the volar lunate facet. Similarly, shearing marginal fractures of the entire volar rim such as volar Barton’s fractures, may also demonstrate an increased teardrop angle.⁹

Sagittal and axial CT’s (Fig. 17c and d) show isolated fracture of the volar lip of the lunate facet with volar displacement. A standard volar approach and volar locked monoblock plating cannot achieve adequate fixation of this fragment, which can lead to its escape and volar subluxation of carpus.¹⁰ To get good exposure of this fragment, an extended carpal tunnel approach was utilized (Fig. 18a). Dissection was performed between the ulnar neurovascular bundle and flexors to get exposure of the displaced fragment (Fig. 18b). It is helpful to place a bump behind the wrist when performing this approach. This reduces the tension during retraction, on the flexors and median nerve and allows for easier exposure. Fixation was achieved with a buttress plate and a cannulated screw with washer (Fig. 18c). Post-operative radiographs show restoration of anatomy (Fig. 19). A good functional outcome was obtained at 3 months follow up (Fig. 20). Wrist flexion and extension continued to improve up to 12 months.

Fig. 17.

PA view (17a) shows an isolated volar ulnar corner fracture. Lateral view (17b) shows increase in teardrop angle. Sagittal (17c) and axial (17d) CTs show isolated lunate facet fracture.

Fig. 18.

Extended carpal tunnel approach is suitable to get exposure of this fracture fragment (18a). Dissection performed with a bump behind the wrist so that tension on flexors and median nerve is reduced (18b). Fixation achieved with a buttress plate and a cannulated screw with washer through the fragment

Fig. 19.

PA and Lateral radiographs showing restoration of the teardrop angle and radiocarpal alignment.

Fig. 20.

Patient obtained full forearm rotation and slightly restricted wrist flexion-extension arc at short term follow up.

Other fixation methods can also be used to fix these fractures based on the fragment size and geometry. For very small lunate facet fragments, a tension band construct around the volar ligaments can work very well (Fig. 21). This may be passed either through the distal radial metaphysis as described by Chin and Jupiter¹¹ or around a screw utilized as a post as demonstrated here.

Fig. 21.

PA and Lateral radiographs showing a tension band construct with a screw used as a post to obtain fixation of small lunate facet fragments. Also seen is fixation of radial styloid and scaphoid fractures.

5. Outcomes

Careful evaluation of X-rays and obtaining pre-operative CT scans is essential to determine the fracture patterns that will benefit from alternative approaches and fixation to restore anatomy. For radiocarpal fracture-dislocations, a loss of about 30–40% of total wrist flexion/extension arc has been reported.^{4, 5, 6} Worse outcomes are associated with persistent articular incongruity, persistent neurological deficit, associated carpal fractures and residual ulnar translocation of the carpus.^{4, 5, 6} Good to excellent short-term outcomes have been reported in literature. Post-traumatic arthritis is commonly seen in these patients and is likely related to persistent articular incongruity or intercarpal instability. Post-traumatic arthritis does not necessarily result in a painful wrist at short term follow up.

6. Pearls

• 1.Pre-operative CT scan including 3D reconstruction is often helpful in determining fracture patterns and treatment planning, including hardware size and placement.
• 2.One needs to be facile with all the common approaches to the distal radius as they are often used in combination for fragment specific fixation
• 3.A dorsal spanning plate should be considered for additional stability or to protect tenuous bony/ligament repair.
• 4.DRUJ stability should be assessed at the end of each case and ulnar styloid or TFCC repair might be needed to restore DRUJ stability. In our experience, this is extremely rare.
• 5.A dorsal approach allows direct visualization of the joint surface as well as recognition of carpal fractures or intercarpal ligament injuries.
• 6.Careful and meticulous contouring is needed for dorsal plates to prevent dorsal tendon irritation. In addition, subperiosteal dissection to lift the second and fourth dorsal compartment is critical to have a layer of tissue between the tendons and hardware after closure. We do not routinely remove all dorsal plates; however patients are counselled that there is a higher chance of plate removal. Any symptomatic hardware is removed after confirming fracture union, especially if there is swelling or crepitation around the hardware.

7. Conclusion

Volar locked plating has become the most common fixation strategy employed for distal radius fractures. There are many fracture patterns, as outlined in this review, where a volar locking plate is not the right choice and alternative fixation strategies should be considered.