Biologic plating of unstable distal radial fractures

The increasing incidence of complex fracture patterns after high-energy trauma and the demand for early return to activities of daily living have increased the number of patients requiring operative intervention to treat distal radial fractures. Fractures may be reduced directly and fixed with volar locking plates [1‐3]. This method has also yielded lower complication rates, ranging from 7% to 24%, than other treatment modalities [4]. The development of an internal fixator with locking plate technology has increased the rate of biologic fixation through minimally invasive plate osteosynthesis (MIPO, bridge plating). This method preserves soft tissue around the fracture site and prevents surgical morbidities of direct reduction in treating comminuted fractures of the lower limbs [5, 6]. Less is known, however, about the results of bridge plating for distal radial fractures [7‐9].

Many factors influence the management of distal radial fractures, including the low complication rate of the open method, lesion size, and the easy manipulation and restoration of anatomic continuity using closed maneuvers. In addition, the postoperative radiologic and clinical outcomes of MIPO and conventional plating for distal radial fractures did not differ significantly [9]. The only advantages of MIPO were reported to be the preservation of the pronator quadratus (PQ) muscle and cosmesis, suggesting that conventional plating should be preferred to MIPO, provided that adequate reduction and sufficient fixation could be addressed [7‐9]. Therefore, the clinical relevance of MIPO for distal radial fracture remains unclear.

Because MIPO involves indirect reduction through separate incisions, there are technical issues involved, with optimal results depending on anatomic restoration of the articular surface and extra-articular realignment [6]. However, few reports have assessed the indirect reduction technique involving MIPO for distal radial fractures [10]. This retrospective analysis of prospectively enrolled patients describes our experiences with bridge plating of distal radial fractures using a PQ-sparing approach, including the reduction technique, focusing on the usefulness and suggested indications of this method.

The study protocol was approved by the ethics committee of our institution. Consecutive subjects with unstable distal radial fractures were enrolled prospectively from June 2006 to December 2010, and the results of bridge plating using a PQ-sparing approach were analyzed retrospectively. All patients with distal radial fracture were initially managed in the emergency room with closed reduction and splinting. This study excluded patients aged < 18 years, those with concomitant upper extremity injuries (e.g., carpal bone injury, forearm fracture, elbow, and humeral fractures), patients with pathologic fractures, patients who had previously undergone surgical treatment of the same wrist, and those whose fractures were fixed with a 3.5 mm T-plate. The 2.4 mm volar distal radius plating system (LDRS®; Synthes, Oberdorf, Switzerland) was used in all cases of volar plate fixation. Each patient was followed up for more than 36 months after surgery.

The plain radiographs and CT scans of all patients were reviewed by two investigators using the Picture Archiving and Communication System (PACS), with their classifications verified according to the AO comprehensive classification system (AO/OTA) [11]. All subjects provided uniform informed consent that the choice of direct fixation or bridge plating through a PQ-sparing approach for each distal radial fracture would be determined intraoperatively based on several factors, including the quality of intraoperative reduction, an unexpected fracture line, and unknown causes.

This study enrolled 33 wrists of 28 patients, 12 men, and 16 men. Their mean age at surgery was 56.8 years (range, 25–83 years) and their mean follow-up duration was 47.5 months (range, 36–67 months). Two patients were lost during follow-up because of death (one suicide and one car accident). One patient underwent emergency surgery on the day of injury, but most underwent surgery about 7 days after injury. The causes of injury to the 28 patients included falling (n = 1), traffic accident (n = 12), industrial trauma (n = 2), and falling while standing (n = 13).

Of the 33 fractures, ten were type 23A, including four 23A2 and six 23A3 fractures, and 23 were type 23C, including 15 23C1 and eight 23C2 fractures. There were two open fractures, one Gustilo-Anderson (GA) type I and one GA type IIIA. The GA type I fracture was treated as a closed fracture on the day of the injury, whereas the type IIIA fracture underwent emergency surgery and application of a spanning external fixator because the distal ulnar head was protruding through the open wound.

Of the 33 fractures enrolled, none required intraoperative conversion to direct open reduction. Twenty-six patients (31 fractures) were managed with a single-stage operation, which included a surgical delay for conditioning the soft tissue around the injured wrist. However, the remaining two patients (two fractures) underwent staged definitive fixation as soon as the status of the soft tissue permitted. The average time from injury to surgery was 5.8 days (range, 0–16 days). One patient with an open fracture was initially treated with emergency irrigation and debridement in the operating room, followed 16 days later by definitive fixation, after recovery of the soft tissue envelope. The other patient presented with a crush injury, which resulted in comminuted fractures of the distal radius and ulna with severe swelling. This patient was initially treated with plate fixation of the ulna and application of the spanning external fixator. The time interval from the first operation to definitive fixation was 7 days. The mean operative time for all bridge plating procedures was 61 min (range, 33–98 min), and all 33 fractures were united without secondary procedure to promote bone healing.

Despite closed maneuvers and a surgical delay of more than 2 weeks in four patients, extra-articular realignment was achieved using the above technique, with all articular fractures showing restoration of joint incongruity to < 2 mm and significant restoration of all radiologic parameters (Table 1) sufficient for statistical significance. The radio-ulnar index (RUI) [14] was changed to a negative value by distraction using a spreader. Radiographs taken at the final visit revealed that the radiologic parameters were well maintained, except for slight losses of radial length and radial inclination in some wrists. Of the 23 wrists with articular fractures, 15 23C1 and eight 23C2, all but one with a C2 fracture had articular gaps < 2 mm. The patient with significant articular incongruity did not wish to undergo a second operation because of associated injury to the head and abdomen.

At final evaluation, all patients had achieved nearly full finger range of motion; that is, they were able to touch their palms with the fingertips and to fully extend their fingers to a neutral position. In addition, all patients achieved wrist flexion, as assessed by a goniometer, having > 90% motion compared with the uninjured wrist [17]. The average MMWS score was 92.6 points (range, 75–100 points), and 30 wrists (90.9%) showed excellent and good MGWS results. Overall outcomes were excellent in 15 patients, good in 10, and fair in three. None of these patients had residual wrist pain or sleep disturbance due to pain, and all were able to perform daily activities without restriction. During follow-up, however, three patients with excessive radial length experienced mild pain in the distal radio-ulnar joint at the first outpatient follow-up visit. Compared with the average RUI, the RUIs differed after surgery in these patients by 4.0, 4.0 and 5.0 mm, differences that were significant. Pain in all three of these patients resolved within 6 months.

None of these patients experienced deep infections or wound complications that required additional surgery. No patient complained of plate-related symptoms or underwent plate removal [18]. Five patients developed postoperative complications related to indirect reduction (Table 2). Two had insufficient reduction of the distal articular angle that was not fully restored to volar tilt by indirect methods, whereas three experienced transient pain in the distal radio-ulnar joint due to radial length overcorrection. None of these patients, however, experienced other conventional complications of volar plating, such as extensor tendon rupture, injury of the median nerve, or loosening.

Use of a volar locking plate has advantages in treating unstable fractures of the distal radius, as it is accompanied by osteosynthesis. The volar locking plate has expanded the indications for operative treatment of these fractures and greatly improved their clinical and radiologic outcomes [1, 3]. However, despite the popularity of bridge plating to treat complex fractures of the lower limbs, only a few reports have described the use of this technique to treat distal radius fractures [7‐10, 19‐21]. Although bridge plating using a PQ-sparing approach may have the advantage of PQ muscle preservation, the use of small incisions can prevent acceptable fracture reduction [7, 8]. Sen MK et al. indicated that this technique should not be used if it compromises the adequacy of reduction or fixation of the distal radius and that it be performed only in carefully selected patients [8].

Despite the proven benefits of direct reduction and anatomic fixation for distal radial fracture, the authors have adopted the concept of extra-articular realignment during prospective enrollment, especially for indirect reduction of metaphyseal fragments in accordance with MIPO technique. Compared with the concept of conventional anatomical reduction, extra-articular realignment is more focused on realignment of the injured limb by restoring the alignment index (length, rotation, and axis) rather than by anatomic reduction of the fracture fragments (Fig. 4). The reduction of distal radial fractures should focus on the restoration of radial length because most problems occurred in patients who achieved fair or poor restoration of radial length after conservative management [14]. Radial length was found to be automatically re-established upon restoration of anatomic continuity of the volar cortex through direct reduction [22]. Automatic restoration should not be expected, however, if a volar cortex is comminuted at the metadiaphyseal area or the fracture surfaces could not be opened, such as in the PQ-sparing approach, and an additional procedure might be needed to achieve the original length. A distractive technique using a spreader could be easily applied, similar to a femoral distractor [10]. Compared with the use of a large distractor or provisional external fixator to restore limb length [23], bridge plating with distractive technique has several benefits. That is, the reduction force could be controlled gradually by the surgeon and verified in the coronal and sagittal planes using an image intensifier in real time. Five wrists, however, experienced complications related to reduction obstacles, including two with undercorrection of the volar/residual dorsal tilt and three with overcorrection of radial length. Compared with the uninjured wrist, the average radial length of the injured wrist, which is strongly associated with clinical outcomes [24], was restored from 3.7 mm preoperatively to 11.2 mm at last follow-up. Although the effects of shortened radial length are widely known, the effects of overlengthening have never, to our knowledge, been reported. Although the prognosis of wrists with overlengthening has not been determined, none of the patients in the present study experienced any complications related to the procedure until final follow-up.

Following the introduction of the 2.4 mm volar locking plate system, five locking screws could be inserted into the subchondral row of the distal fragment [1]. Thus, indications for this procedure may be expanded to include extra-articular fractures with metaphyseal comminutions in both cortices, regardless of the size of the distal fragment (Fig. 4). Single volar plating of an articular fracture requires the articular fragment to be of sufficient size, large enough for at least two screws of the 2.4 mm locking plate system [25]. We found that, following satisfactory reduction of the articular surface, the indications were similar for bridge plating and conventional options in the treatment of articular fractures. However, it is very important to verify the reduction status of the radial styloid fragment, which is closely related to articular step-off and radial inclination. Thus, single volar plate fixation using the PQ-sparing approach could be performed if the radial styloid fragment of the articular fracture was sufficiently large for the fixation of two or three screws and if articular congruity was restored by indirect reduction and percutaneous maneuvers. However, if reduction cannot be obtained, it is better to switch to ORIF (Fig. 5).

Our experience clearly demonstrated that the term biologic fixation through bridge plating (BFBP) is more accurate than MIPO, since the two incisions might be larger in size than those of the conventional technique. In addition, this retrospective analysis indicates that BFBP has several potential limitations. First, the use of two incisions may lead to cosmetic problems, especially in younger patients. Second, the operation time was longer and radiation exposure was greater with BFBP than with the conventional technique. Third, the PQ-sparing technique was not compared directly with the conventional technique [20]. Nevertheless, our study, as well as others [19‐21], reported satisfactory outcomes with the PQ-sparing technique, suggesting that the latter may reduce postoperative pain, enable motion exercises to be started sooner after surgery, and maintain the muscular envelope of the distal radius, thus potentially avoiding postoperative complications. As this study was not adequately powered due to the lack of a direct comparison group, further studies are required to optimize plate removal and the degree of radiation exposure, as well as to directly compare the PQ-sparing and conventional techniques.

A combination of bridge plating through a PQ-sparing approach and the distractive technique results in good reduction, with restoration of radial length and reasonable long-term functional outcomes. Compared with the conventional technique, the PQ-sparing technique, despite disadvantages such as technical difficulties, increased radiation exposure, and cosmetic problems, may be helpful in managing metaphyseal comminuted fractures of both cortices with reduced RUI.