17 Common Errors of Volar Plate Fixation

10.1055/b-0039-169257

17 Common Errors of Volar Plate Fixation

Robert J. Medoff, James M. Saucedo

Abstract

Treatment of distal radius fractures has changed dramatically since the introduction of the volar locking plate. As the number of volar plate procedures has increased, the type and frequency of complications have changed as well. Many of these complications are avoidable and result from technical errors related to the surgical approach, misinterpretation of the pattern or mechanism of fracture, incomplete reduction, or errors in surgical technique. Inadequate or inappropriate exposure may cause nerve injury, malreduction, poor positioning of implants, joint penetration, protruding hardware, or inadequate fixation. Applying a plate too distal can result in joint penetration, plate irritation, and tendon problems; whereas placing the plate too proximal can result in loss of fixation from inadequate support and plate lift-off. Errors in the position or length of screws or pegs is another frequent source of complications leading to patient morbidity. In addition, relying too much on the implant for reduction or stretching volar plate indications to include all complex patterns, small rim fragments, extensive comminution, and certain shear fractures may set the stage for catastrophic failure. While the volar locking plate can be a versatile and effective tool for many distal radius fractures, appropriate exposure, reduction, and surgical technique are essential to avoid errors that compromise outcomes.

“We cannot solve our problems with the same thinking we used when we created them.”

– Albert Einstein

The treatment of distal radius fractures has changed dramatically in the past 15 years as volar plate fixation has become a new standard of care. Not surprisingly, as the number of patients treated with open reduction and volar plate fixation have increased, both the character and frequency of complications have changed as well. Although some morbidity associated with distal radius fractures is clearly related to the pattern and complexity of the injury itself, many clinical failures are avoidable and simply caused by errors in the approach or technique of volar plate fixation.

17.1 Background

Several clinical studies have compared clinical outcomes of volar plate fixation to other “more traditional” methods of treatment. Although most show improvement in clinical outcomes in the early postoperative period (the initial 12 weeks postoperatively), few demonstrate superiority of volar plate fixation in long-term outcomes. Wei et al prospectively randomized patients to either volar plate fixation, external fixation, or radial column fixation and found early improvement in the two internal fixation groups at 6 weeks but no difference in outcome scores at 1 year. ¹

Zhang et al performed a meta-analysis on 6 studies totaling 445 patients comparing external fixation and volar plate fixation. ² Although volar plate fixation showed better early clinical outcomes, results were equivalent at 12 months. In addition, the number of reoperations for complications was higher in the volar plate group.

Karatana et al prospectively randomized 130 patients to percutaneous treatment or volar plate fixation. Although volar plate fixation showed better early clinical scores with improved grip strength, clinical outcomes at 1 year were not significantly different. ³ Volar plate complications included extensor pollicis longus rupture, plate removal due to flexor tendinopathy, and late articular collapse with intra-articular penetration.

Finally, Arora et al prospectively randomized 73 patients aged 65 years or older to either volar plate fixation or nonoperative management. ⁴ Although operatively managed patients had better disabilities of arm, shoulder and hand (DASH) and patient-rated wrist evaluation (PRWE) scores in the first 6 weeks, no difference was demonstrated after 6 weeks. Complications were nearly three times higher in the volar plate group (36%). These studies underscore the technical complications associated with volar plate fixation.

A variety of errors may expose patients to complications and morbidity with volar locking plate fixation of distal radius fractures. Many are avoidable, with some related to surgical technique and others to design limitations of the plate itself. Specific categories of errors include inadequate or inappropriate surgical exposure, hardware related issues, tendinopathies, and inadequate reduction and/or fixation problems (▶Table 17.1). Recognizing these pitfalls can help avoid complications and morbidity.

**Table 17.1** Categories of errors with volar plate fixation
Errors of surgical approach Inadequate exposure Nerve injury Inadequate reduction Flexor tendinopathy/rupture Plate design features Plate position distal or volar to pronator insertion ridge or volar rim Inadequate subchondral support/migration of distal fragment Protruding hardware Retained instrumentation Protruding screw tips Attempt to lag dorsal fragments Incorrect screw length Improper interpretation of intraoperative X-rays Complex, distal, multiarticular fracture pattern Complex intra-articular pathology not amenable to volar plate fixation Very distal fracture lines with inadequate buttress by volar plate Associated ulnar column injuries Excessive or inadequate plate width Inadequate reduction Intra-articular incongruity Radial shortening Coronal malalignment Inadequate plate length or placement Subchondral screws/pegs too far from subchondral bone Plate of insufficient length Patient/biologic issues Noncompliant patient Functional quadruped Severe osteoporosis

17.2 Errors of Surgical Exposure

Most distal radius fractures are exposed with a volar approach. ⁵ ^, ⁶ ^, ⁷ The palmar cutaneous branch of the median nerve in the subcutaneous tissues between the flexor carpi radialis (FCR) tendon and palmaris longus is at risk of injury with incisions placed too far ulnar, resulting in painful neuromas and palmar numbness. Combining an FCR incision with a traditional carpal tunnel approach crosses this nerve, which may result in transection and patient morbidity (▶Fig. 17.1). Radially, neuropraxia or injury of the sensory nerves may be caused by overzealous retraction or extension of the skin incision radially.

**Fig. 17.1** Combining an flexor carpi radialis approach with a standard carpal tunnel exposure results in transection of the palmar cutaneous branch of the median nerve and neuroma.

Inadequate exposure, especially in large patients or those with extensive swelling, can result in problems with reduction, plate position, and secure fixation. In addition, overzealous retraction to visualize the ulnar corner may result in iatrogenic injury to the median nerve. Releasing the FCR distally or using the interval ulnar to the FCR tendon may help provide full visualization of distal radius fragmentation.

A volar ulnar approach between the digital flexor tendons and the ulnar neurovascular bundle is another option for visualization of the intermediate column (▶Fig. 17.2). This approach should be considered when direct access to the volar ulnar corner is required, whether planned preoperatively or required intraoperatively because of inadequate visualization.

**Fig. 17.2** Volar ulnar approach. **(a)** Skin incision. **(b)** Direct access to volar ulnar corner with fixation using a volar buttress pin (TriMed).

Some injury patterns, such as extensive comminution of the radial column, dorsal comminution, extremely distal fracture components, or fragmentation of the sigmoid notch, are not adequately fixed with a volar plate and may require alternate or additional exposures.

17.3 Hardware-Related Errors

Although safe and adequate exposure is essential for open treatment of distal radius fractures, appropriate implant selection and positioning are also important. Applying a plate in the wrong position may result in morbidity, ranging from minor hardware irritation to major complications such as tendon rupture or fracture collapse. A position that is too far proximal places locking screws in softer metaphyseal bone and not buttressing the dense subchondral surface. Especially in patients with osteoporosis, subsidence of the distal fragment can result in loss of reduction, shortening, and dorsal angulation. In addition, the distal fragment may drift away from the distal end of the plate resulting in plate “lift-off,” which may, in turn, lead to abrasive wear of flexor tendons against the distal edge of the plate and eventual rupture (▶Fig. 17.3). In addition, distal radioulnar joint (DRUJ) dysfunction may occur, resulting in loss of forearm rotation or early arthrosis. ⁸

**Fig. 17.3** Positioning error. **(a)** Lateral injury radiograph. **(b)** Although reduction is anatomic with near normal lateral carpal alignment and teardrop axis, locked distal fixation is too far proximal from the subchondral bone, resulting in an ineffective buttress of the joint surface. **(c)** Distal fragment has drifted proximally and shifted dorsally away from the plate (dorsal shift of capitate center, depression of teardrop angle), exposing flexor tendons to abrasive wear against plate edge.

Misinterpretation of radiographs may also result in inadvertent joint penetration. The 10 degree lateral radiograph should be routinely used to confirm proper position of locked distal screws behind the subchondral bone, especially along the ulnar two-thirds of the joint surface (▶Fig. 17.4). ⁹

**Fig. 17.4** 10 degree lateral radiograph. **(a)** Elevating the forearm about 10 degree aligns the ulnar two-thirds of the radiocarpal joint to the axis of the beam. **(b)** This view provides accurate assessment of the proximity of the locked distal fixation to the subchondral bone.

Screw penetration of the radiocarpal or even DRUJ is another error of technique (▶Fig. 17.5). Standard fixed-angle plates have a single, specific geometry for the footprint of the locking pegs, and optimal subchondral support only occurs when placed in a single, specific location on the volar surface of the radius. The shape of a particular plate can affect the position of distal fixation screws since variation in the curve of the metaphyseal flare determines where a specific plate design sits naturally on the bone. As a result, standard fixed-angle plates require more precise placement to position fixed-angle screws against subchondral bone. In contrast, plate designs with polyaxial locking screws allow more flexibility, since the surgeon can individually orient each distal locking screw optimally against the subchondral surface. This may also allow more uniform subchondral support over a wider range of plate positions (▶Fig. 17.6).

**Fig. 17.5** Positioning error resulting in articular penetration by distal locking screws. (Courtesy of Jesse Jupiter, MD). **(a)** Anteroposterior and lateral X-ray images after surgery show plate applied too distal and too radial with articular penetration by distal pegs and screws. **(b)** Confirmation of articular penetration on CT scan. **(c)** Articular penetration confirmed at time of surgery by direct exposure of joint.

**Fig. 17.6** Variable locking volar plate design. **(a-i)** Standard fixed-angle plates orient the pegs in a position in the distal fragment based on the location of the plate. Plate position too proximal may not provide adequate subchondral support. Positions too distal risk joint penetration. **(a-ii)** Variable-angle locking design allows independent positioning of each distal support peg over range of plate locations. **(b)** Variable-angle locking plate with uniform subchondral support.

Although more forgiving in terms of plate position, variable-angle locking designs come with their own set of problems. With a greater range of insertion angles, additional care is needed to avoid radiocarpal or even DRUJ penetration. Additional views such as the axial tangential view and pronation oblique views can help identify violation of the sigmoid notch and DRUJ (▶Fig. 17.7). ¹⁰ ^, ¹¹ In addition, intraoperative clinical evaluation of DRUJ for stability and crepitance helps avoid unrecognized residual joint instability, articular incongruity, and inadvertent hardware penetration.

**Fig. 17.7** Axial tangential view for assessing position and dorsal penetration of the distal locking screws; this view also provides some visualization of the sigmoid notch.

Patients vary in bone size and shape, and no single plate can be expected to fit the complete range of morphologies in a given population. In large patients, standard implants can leave significant portions of the distal radius uncovered, requiring wider plate designs or additional fixation. In contrast, in petite individuals, standard plate sizes may protrude beyond the edge of the bone leading to hardware irritation (▶Fig. 17.8). These problems are easily avoided by detailed preoperative assessment and ensuring that a range of implant sizes is available at the time of surgery.