Radiological and Clinical Outcome of Distal Radial Fractures Managed by Variable Angle 2.4 mm Titanium Volar Plate

Objective: To evaluate radiological and clinical outcome in fractures of the distal radius treated with internal fixation by applying variable angle 2.4 mm volar locking plate. Study design: Prospective interventional study. Place and duration of study: Hand and Upper Limb Surgery (HULS), Lahore, Pakistan between January 2014 and December 2015. Methodology: Forty two patients (34 males, 08 females) with different types of fractures of distal radius were treated. Open reduction and Internal fixation was performed by applying 2.4 mm titanium variable angle volar locking plate. Anatomical restoration was evaluated by good-quality postero-anterior and lateral radiographs obtained preoperatively, immediately postoperatively and 09 months of follow up to evaluate Radial Height (RH), Radial Inclination (RI) and Volar Tilt (VT). Data was analyzed by One way repeated measure ANOVA test. Results: There was perfect anatomical restitution in AO type A and B fractures that retained till 09 months follow up. In type C fractures, there was significant postoperative improvement but slight loss in radiological parameters by 09 months that was insignificant with P-value less than 0.01. There was credible improvement in wrist movements and grip. Conclusion: The rigid characteristics of variable angle volar plate provide the best anatomical restoration and fixation of distal radius fractures and maintain stability to promote early postoperative wrist motion.


Introduction
Fractures of the distal radius are extremely common. Incidence rates vary from 5.7 to 124.6 per 10,000 persons per year [1]. These fractures are being managed uniformly with conservative means showing satisfactory results [2]. There is a recent rise in high energy fractures of the distal radius in young adults, because of motor vehicle accidents and recreational activities, which invariably require surgical management [3].
Studies have shown that, in the distal radius fractures, function is related to the radiographic findings [2]. Restoration of normal alignment and articular congruity after a displaced fracture can be difficult but is essential for a good functional outcome in terms of early wrist motion, improvement in range of motion and grip strength [4,5]. It has been shown in the laboratory and clinical studies that extra and intra-articular malunion alters the function of wrist [4,6,7]. Conservative treatment options may result in inability to manipulate displaced or depressed articular fragments and may also overlook associated soft-tissue and ligamentous injuries, which are being recognized with increasing frequency [8,9]. A variety of treatment options are available including closed reduction and cast immobilization, K-wire fixation, external fixation and Open Reduction and Internal Fixation (ORIF) with volar locking plate. The latter is a fixed angle implant which is being widely promoted by the surgeons and implants manufacturers [10] because biologically fracture treatment aims at restoring the axis and length of the injured bone, reconstructing the articular surface, and achieving a stable fixation that allows early motion and weight bearing [10]. Different studies have proved that internal fixation with fixed angle volar plate showed better results in terms of restoration of anatomy, fixation, stability and function in comparison with other methods.
The purpose of this study was to determine anatomical restoration and stabilization of acute fracture of the distal radius and clinical outcome, treated with ORIF by applying variable angle locking volar plate.

Materials and Methods
This was a prospective study of 42 patients with distal radius fractures who were treated by ORIF by using fixed angle volar plate in Hand and Upper Limb Surgery (HULS) Centre Lahore, pakistan for a period of two years from January 2014 to December 2015. Two surgeons performed the procedure. All patients with displaced fractures were offered ORIF. Willing patients underwent the surgery. Patients having age less than 16 Years and more than 75 Years, open fractures, bilateral fractures, who had undergone satisfactory closed reduction and external fixation or who had associated multiple injuries were excluded from the study.
All fractures were classified according to AO (the Association for Osteosynthesis) classification system [11] by getting Postero-Anterior (PA) and Lateral (Lat) views of radiographs of the wrist at the time of the initial injury. Some patients needed CT scan of wrist for further evaluation of intra-articular fractures.
All these patients were admitted to the hospital and operated on as early as possible, depending on local condition of tissue, oedema, hematoma and fitness of the patient for anaesthesia. After informed written consent, ORIF was performed via a volar approach and using 2.4 mm titanium variable angle volar locking plates (Figures 1 and 2). Surgery was performed under regional or general anesthesia and fluoroscopic guidance. All surgeons performing the surgery had necessary experience with the procedure and familiarity with the used implants. Post-operative cast splintage of the wrist did not exceed 10 days.

Radiographic evaluation
To evaluate type of fracture and post fixation restoration of anatomy, the study design mostly depends upon plain radiographs made at the patient's initial visit (pre op), immediate postoperatively (post op) and at 09 months of follow up (follow up). Radiological parameters included measurement of Radial Height (RH), Radial Inclination (RI) and Volar Tilt (VT) through PA and true lateral radiographs.
All imaging studies were assessed in a blind fashion by 2 independent investigators, and the 2 measurements were averaged. PA view provided information about RH (Radial height) or radial length and RI (Radial Inclination). Normal RI is 22 degrees and it was measured as an angle formed between a line drawn through the tip of the radial styloid and the medial corner of the lunate facet and a line drawn perpendicular to the long axis of the radius ( Figure 3). Normal RH is 11 mm and was measured as the distance between 2 lines perpendicular to the long axis of the radius, one drawn at the tip of the radial styloid and another drawn at the distal ulnar articular surface ( Figure 4). In the Lat view, the VT (Volar Tilt) of the distal radius articular surface was measured [12,13]. Its normal value is 11degree ( Figure 5).
These measurements were taken at three stages i.e; pre op, immediately post op and at 09 months follow up. The differences between various measurements were evaluated by One way measure ANOVA test. Statistical significance was defined as p < 0.05.

Results
Total 42 patients underwent this surgery those included 34 males and 08 females. The mean age and Standard Deviation (SD) at the time of the injury was 40.64 ± 12.36 years (range from 19 to 70 years). Twenty two (52.4%) fractures involved right side while 20 (47.6%) fractures occurred on the left. According to AO classification, most of the cases were of C (n = 21) 50% and B (n = 10) 23.8% type probably because of increased incidence of high velocity injuries ( Table 1).  Radiographic evaluation in different stages of management.
Distal radius deformity was assessed by measuring RH, RI and VT at different stages of treatment. There was significant improvement in RH and RI in initial post op stage that almost retained till 09 months of follow up (Table 2, p < 0.05 for all comparisons). Similarly VT was comprehensively improved from an average of -4.78° to an average of 11.40° immediately after surgery, and then remained persistent at 11.21° at the time of follow up of 09 months (Table 2).  In terms of type of fractures, all three parameters were perfectly improved in AO type A and B fractures. However, in type C fractures, final mean achievement in RH and VT was 10.71 ± 0.95 mm and 10.76 ± 1.30 degrees respectively, but the parameters were still in quite acceptable range ( Table 3).

Clinical outcome
Averagely, surgeries were performed within 3 to 20 days of injury. Average hospital stay was 04 days. There was no immediate post operative complication i.e infection or nerve injury. Wrist movement was started within 1-2 weeks. Volar flexion and dorsal flexion were

Discussion
Distal radial fractures are being treated by traditional methods in our country i.e. Closed reduction with Cast immobilizations, external fixation and ORIF with conventional T-plate. As mentioned earlier, Studies have shown that, in the distal radius fractures, function is related to the radiographic findings [2]. Intra or Extra-articular malunited fractures have been shown to alter function and patient satisfaction with the outcome of treatment. In a study, Arora et al. [14] mentioned an obvious clinical deformity in 77% of cast group and malunion occurred in 89% of primarily reduced fractures. Another study showed 33% patients managed with pins and plaster treatment had some complications due to their pins and 16% required reoperation [15]. External fixation is a popular method to improve the reduction of osseous deformity but cannot effectively protect comminuted distal radial fractures from loss of reduction, which may be associated with shortening and displacement [16].
Although Rozental et al. [17] showed satisfactory results with closed reduction and pin fixation for unstable distal radius fractures, but there is insufficient evidence to confirm a better reduction in displacement, functional outcome and minimum complications in patients managed conservatively [2].
Evidence in the literature indicates a strong correlation between restoration of bone anatomy and recovery of function [18], because the position of the fracture at the time of union rather than the position at the time of presentation has the greatest correlation with long-term functional results [19]. Assessment of type of fractures was vital to predict the outcome of management because comminuted intraarticular fractures of distal radius are very difficult to manage. Severe comminution is associated with shortening and re-displacement [12]. This corresponds to the visco-elastic characteristic of ligaments [20]. This prevents longitudinal traction alone from restoring volar tilt and may explain why the volar tilt of the distal radius deformity did not improve significantly with conservative measures.
For distal radius fractures, high frequencies of ligamentous injuries are commonly associated with both intra-articular and extra-articular subtypes [20]. These are the factors involved in the development of redisplacement even after satisfactory reduction and fixation with Kwires [21]. Even if no ligamentous injuries existed coincidentally and the distal radius fractures were well reduced at the time of initial management, the stretched ligaments will gradually become deformed and the stress relaxed, followed by re-displacement of well reduced fractures as proved in our previous study [22].
The locking plates result in wonderful stability even in the osteoporotic bone that's why there is increased rate of surgical procedures for fractures that had rather been managed conservatively in the past [10]. The use of ORIF with a volar fixed angle implant resulted in stable fixation, allowing early postsurgical wrist motion. Moreover, intra-articular step-off, volar tilt and radial height were better in ORIF group and early wrist ROM was initiated without loss of reduction [23]. Wright et al. [23] showed in their study averaged 5 degrees volar tilt and 25 degrees radial inclination improvement while ORIF with volar plating significantly improved these parameters in our study. In a study by Figl et al. [6] 75% patients had no radial shortening and 25% had a mean radial shortening of only 1.8 mm compared to our study where 50% maintained their height while other 50% lost only 0.9mm. While in comparison to on average 22 degrees radialinclination and 6 degree volar tilt our study showed 21.09 degrees and 11.22 degrees respectively [6].
Another study showed that radiographic results (VT, RH and RI) were significantly better in ORIF group treated by using fixed angle volar plate rather than in those treated by cast immobilization [14].
The purpose of our study was to establish the stabilization effect of low profile fixed angle volar plate on fractures of the distal radius in our set up. As we have noted, the bony deformity of the distal radius showed significant improvement in the measurements of RH, RI and VT immediately after reduction and fixation with fixed angle volar plate that was maintained successfully till follow up of 09 months (Tables 2 and 3). We found that Intra-articular fractures i.e., Type B and C treated by fixation with fixed angle volar plate significantly improved the RH, RI and VT. Fractures with less comminution got perfect correction after fixation that persisted till follow up of 09 months (Table 4). Our results are well comparable with many international studies rather showed better findings in VT [6,[23][24][25].
However conservative measures are acceptable even with disability in elderly people and patients with dementia or multiple medical comorbidities [26].

Conclusions
There is increased tendency of young patients to sustain comminuted distal radius fractures due to high energy trauma. Conservative measures may improve the reduction of type B and C fractures but cannot assure the maintenance of reduction. Most patient suffering from distal radius fractures of Type B and C treated conservatively fall into malunion.
Restoration of anatomy is the hall mark of this surgery. The peculiar characteristics of variable angle volar plate provide the best alternative to the traditional techniques of distal radius fixation which is strong enough to allow for early postoperative motion and the functional outcome is credible.