Key points

Background

Distal radius fractures are common upper extremity injuries, with an annual incidence of 16.2 fractures per 10,000 persons, or more than 640,000 cases per year. Prior studies have highlighted the significant variation in treating these injuries owing to regionality, patient age, sex, race, and whether a hand surgeon is the treating provider. Regardless, the burden of distal radius fractures is expected to increase as the US population ages, concomitant with a trend toward more widespread use of internal fixation.

Fixation strategies for distal radius fractures have undergone a rapid shift toward open treatment since the introduction of volar locked plating (VLP), particularly among younger US orthopedic surgeons. In addition to VLP, there exists a myriad of other fixation options, including percutaneous pinning, external fixation (bridging and nonbridging), dorsal plating, dorsal bridge plating, and fragment-specific fixation.

VLP seems to be trending as the most popular choice of fixation, but enthusiasm for this option should be tempered by an understanding of its complications compared with other methods. A recent meta-analysis by Li-Hai and colleagues showed similar complication rates between external fixation and VLP at 30.9% and 23.9%, respectively, but also found a significantly higher rate of reoperation caused by complications in the latter. In a randomized controlled trial with 5-year follow-up, Williksen and colleagues found that the incidence of secondary operations for complications was 31% in patients treated with VLP, which was significantly greater than the 17% incidence in those treated with external fixation and percutaneous pinning. Arora and colleagues reported an overall complication rate of 27%, with flexor and extensor tendon injury being the most frequent complications (57%). The risk of complications may also be higher in elderly patients undergoing VLP, as suggested by a randomized controlled trial by Arora and colleagues that found a 36% complication rate in patients older than 65 years of age. Lutz and colleagues reported similar findings.

There is a vast but largely inconclusive body of evidence regarding the ideal fixation for distal radius fractures. With the resultant lack of definitive evidence-based guidelines and overall complication rates exceeding 30%, familiarity with the complications of various methods of distal radius fixation can better equip practicing surgeons in making informed decisions on a case-by-case basis.

Background

Distal radius fractures are common upper extremity injuries, with an annual incidence of 16.2 fractures per 10,000 persons, or more than 640,000 cases per year. Prior studies have highlighted the significant variation in treating these injuries owing to regionality, patient age, sex, race, and whether a hand surgeon is the treating provider. Regardless, the burden of distal radius fractures is expected to increase as the US population ages, concomitant with a trend toward more widespread use of internal fixation.

Fixation strategies for distal radius fractures have undergone a rapid shift toward open treatment since the introduction of volar locked plating (VLP), particularly among younger US orthopedic surgeons. In addition to VLP, there exists a myriad of other fixation options, including percutaneous pinning, external fixation (bridging and nonbridging), dorsal plating, dorsal bridge plating, and fragment-specific fixation.

VLP seems to be trending as the most popular choice of fixation, but enthusiasm for this option should be tempered by an understanding of its complications compared with other methods. A recent meta-analysis by Li-Hai and colleagues showed similar complication rates between external fixation and VLP at 30.9% and 23.9%, respectively, but also found a significantly higher rate of reoperation caused by complications in the latter. In a randomized controlled trial with 5-year follow-up, Williksen and colleagues found that the incidence of secondary operations for complications was 31% in patients treated with VLP, which was significantly greater than the 17% incidence in those treated with external fixation and percutaneous pinning. Arora and colleagues reported an overall complication rate of 27%, with flexor and extensor tendon injury being the most frequent complications (57%). The risk of complications may also be higher in elderly patients undergoing VLP, as suggested by a randomized controlled trial by Arora and colleagues that found a 36% complication rate in patients older than 65 years of age. Lutz and colleagues reported similar findings.

There is a vast but largely inconclusive body of evidence regarding the ideal fixation for distal radius fractures. With the resultant lack of definitive evidence-based guidelines and overall complication rates exceeding 30%, familiarity with the complications of various methods of distal radius fixation can better equip practicing surgeons in making informed decisions on a case-by-case basis.

Postoperative infection

Infection is an ever-present risk following distal radius fixation because of violation of the integument. Staphylococcus aureus remains the most common isolated microbe, followed by mixed flora. Methicillin-resistant S aureus is also increasingly being cultured from hand and wrist infections and should be considered as a causative organism.

Pin-track or superficial infections following external fixation represent the most common type of postoperative infection following distal radius fixation. A 2007 Cochrane Systematic Review found a 25% overall incidence, with smaller series reporting even higher rates in excess of 50% to 67%. Percutaneous pinning has a lower, albeit still present, risk of pin-track or superficial infection, with another 2007 Cochrane Review finding a range from 0% to 10%. A more recent meta-analysis of 7 randomized controlled trials by Chaudhry and colleagues revealed an 8.2% incidence. Other smaller series report ranges from 2% to 34%. Pins left outside the skin are associated with a significantly greater infection rate than those buried deep to the skin. Nearly all of these studies reported infection resolution with oral antibiotics with or without pin removal.

In contrast, open reduction and internal fixation (ORIF) with volar and/or dorsal plating results in lower infection rates, ranging from 0% to 3%. Open fractures of the distal radius clearly increase the risk of postoperative infection, regardless of fixation, with the largest series reporting a 44% incidence, of which 68% were soft tissue infections and 32% were caused by osteomyelitis.

Extensor tendon injury

Volar Plating

Extensor tendon injury, particularly EPL rupture, is a well-documented complication of volar plating or any hardware placed in a volar-to-dorsal trajectory. This injury is typically caused by drill bit penetration or prominent dorsal screw tips ( Fig. 1 ). The incidence of this complication is significant, with a series of 35 patients by Al-Rashid and colleagues reporting an 8.6% rate of EPL rupture following VLP fixation. Arora and colleagues examined a larger cohort of 114 patients and found a lower incidence of 1.8%. More recently, Zenke and colleagues examined a series of 286 patients and found a rate of 2.1%.

Lateral radiograph of a 36-year-old man with prominent dorsal tip of the proximal screw, which led to EPL rupture.

Symptoms that may herald impending EPL rupture include tenderness and swelling over the course of the tendon. Once rupture has occurred, management is usually in the form of transfer of the extensor indicis proprius (EIP) tendon ( Fig. 2 ) or reconstruction with an intercalary tendon graft. In addition, other extensor tendons can be injured by prominent dorsal screw tips, as shown by reports of EIP and EDC tendon rupture, as well as intersection syndrome.

Intraoperative view of the patient from Fig. 1 with prominent dorsal screw tip ( arrow ), harvested EIP tendon ( asterisk ), and distal stump of ruptured EPL tendon (#).

Short of rupture, prominent dorsal screw tips from volar plating can also lead to tenosynovitis of the extensor tendons. Published studies report incidences ranging from 0% to 14%. This problem is typically addressed with removal of hardware to avoid tendon rupture.

Flexor tendon injury

Flexor tendon injury following fixation of distal radius fractures is less common than extensor tendon injury. Orbay and Touhami stressed the importance of the watershed line, which is the bony transverse ridge found along the volar distal edge of the radius that marks the distal extent of the concave-shaped pronator fossa. The flexor tendons approach bone at the watershed line, and thus plates placed with their distal edges at or distal to this landmark are at risk of irritating the overlying flexor tendons, resulting in tenosynovitis or rupture.

A systematic review of 21 studies from 1973 to 2013 by Asadollahi and Keith found a total of 47 cases of flexor tendon rupture. The mean age of patients was 61 years, with a median interval between surgery and rupture of 9 months. The flexor pollicis longus (FPL) was the most frequently ruptured tendon, followed by the index flexor digitorum profundus. The flexor carpi radialis tendon can also become irritated from volar plate fixation.

In 2 separate series, Arora and colleagues reported 9 out of 114 and 4 out of 36 cases of flexor tenosynovitis that were treated with implant removal. They also documented 2 cases of FPL rupture caused by abrasion from prominent distal screw heads that had become disengaged. Other case reports similarly confirm instances of FPL rupture following application of volar plates at or distal to the watershed line. Chronic steroid use has also been implicated in FPL rupture following volar plate fixation. In addition, FPL rupture can occur at any point following volar plate fixation, with 1 case report occurring 10 years after the patient’s index surgery. Some investigators advocate repair of the pronator quadratus as a preventative measure, which provides a protective tissue layer between volar hardware and the flexor tendons

Carpal tunnel syndrome and median neuropathy

Carpal tunnel syndrome is a known complication of distal radius fractures regardless of treatment method, and can occur acutely, subacutely, or in delayed fashion. The condition is typically caused by increased carpal tunnel pressure, with nerve transaction or entrapment being less common causes.

In a matched cohort study comparing nonoperative versus VLP fixation in elderly patients, Lutz and colleagues found median neuropathy to be the most common complication in both operative and nonoperative groups, reporting an overall incidence of 8.5%. The operative and nonoperative groups each had incidences of 6.2% and 11%, respectively. Arora and colleagues reported a lower incidence of 2.6% following VLP fixation.

A Cochrane Review comparing percutaneous pinning with conservative treatment found comparable rates ranging from 0% to 8%. Another Cochrane Review examining external fixation reported incidences of 5% to 7%. Other studies report similar rates, with a trend toward a higher incidence in patients undergoing volar plating compared with other methods of fixation. More recently, a 2015 analysis of the Swedish National Patient Registry by Navarro and colleagues found the incidence of carpal tunnel release following plate fixation to be 8.7 per 10,000 person-years. This incidence was significantly higher than in those who underwent external fixation (1.6 per 10,000 person-years) or percutaneous pinning (0.9 per 10,000 person-years).

Given the common occurrence of this complication, some surgeons advocate empiric carpal tunnel release in all distal radius fractures undergoing fixation, whereas others suggest a more selective approach limited to patients with preexisting or acute signs of carpal tunnel syndrome. Regardless of approach, focused history taking and physical examination remain crucial at all time points during the treatment period.

Superficial radial nerve injury

Superficial radial nerve (SRN) palsy from isolated volar plating is rare, but is documented following fragment-specific fixation, with a series by Benson and colleagues reporting 10 out of 81 patients with numbness in the SRN distribution. Direct injury to the SRN is more of a concern with percutaneous pinning and external fixation. In addition, both of these modalities are often used for provisional fixation during application of plates and therefore confer a transient risk of intraoperative injury in these instances.

A cadaveric study by Chia and colleagues found that volar and dorsal radial styloid pins were on average 1.5 mm and 0.35 mm away, respectively, from the closest branches of the SRN. The investigators also showed that transverse radial pins were on average 1.1 mm away from the trunk or branches of the SRN (see Table 1 ).

Clinically, Glanvill and colleagues reported a 13% incidence of SRN injury with radial styloid pinning. A 2007 Cochrane Review found rates ranging from 0% to 13% using only percutaneous pinning. Glickel and colleagues documented 1 case of SRN neuropraxia in their series of 54 patients who underwent percutaneous pinning. Karantana and colleagues reported 10 transient SRN palsies out of 64 patients treated with percutaneous pins. Roh and colleagues found 2 out of 38 patients with SRN injury after being treated with external fixation and percutaneous pinning. Kumbaraci and colleagues reported 2 out of 35 patients who sustained SRN injury following similar fixation. A 2007 Cochrane Review found rates ranging from 4% to 13% using both external fixation and percutaneous pinning.

As shown by Glickel and colleagues, the risk of neural and tendon injury can be minimized with the use of small incisions to facilitate direct visualization and soft tissue protectors (syringe tips, blunt large-gauge needles). Because percutaneous pinning remains an integral part of both provisional and definitive fixation of distal radius fractures, awareness of the various structures at risk with different pin configurations is important in minimizing the chance of iatrogenic injury.