Routine X-Rays after the Osteosynthesis of Distal Radius and Ankle Fractures

Abstract

Background

The utility of routine x-rays after the osteosynthesis of distal radius fractures and ankle fractures is questionable. We performed a trial to determine whether such x-rays are justified in patients who have undergone standardized imaging with C-arm fluoroscopy during surgery.

Methods

Patients requiring surgery for a distal radius fracture or an ankle fracture were candidates for inclusion in this prospective, randomized, controlled, non-blinded trial. Standardized intraoperative images were obtained with C-arm fluoroscopy and stored at the end of the operation. The next day, patients in the control group underwent imaging with a standard postoperative x-ray, while those in the intervention group did not. The primary endpoint was a change in the treatment plan, defined as additional imaging or a second operation. The secondary endpoints included the range of motion, pain as rated on the Visual Analog Scale, and a functional outcome analysis (PRWE/FAOS).

Results

316 patients were included in the trial (163 in the control group, 153 in the intervention group), of whom 202 (64%) had radius fractures and 114 (36%) had ankle fractures. The treatment plan changed in twelve patients (3.8%; four in the control group and eight in the intervention group), seven of whom (2.2%; three in the control group and four in the intervention group) underwent a second operation. The frequency of changes in the treatment plan and of reoperations was comparable in the two groups (p = 0.36). On follow-up at six weeks and one year, the results with respect to functional outcomes and pain were comparable.

Conclusion

In this trial, routine postoperative x-rays after the osteosynthesis of distal radial fractures and ankle fractures did not improve the care of patients who had undergone standardized intraoperative imaging.

Over recent years, rising healthcare costs have caused surgeons, as clinical decision makers, to question established standards. Medical interventions are now being assessed for both their medical and economic sustainability in routine daily care. A widely recognized standard that has been rightly questioned based on the results of high-quality studies (1– 3) is the need for routine postoperative X-rays after fracture fixation of the distal radius (1, 3) or after lower-extremity injuries (4), such as ankle fractures (5, 6). In 2015, fractures of the distal radius were the most common fracture in Switzerland, with 127–171 cases per 100 000 patients (7). These figures are in line with findings from the UK (8), the USA (9) and the Netherlands (1). Furthermore, with an increasingly demanding and aging population, the indications for surgical treatment have been significantly extended in recent years (9– 12).

The primary aim of this prospective, unblinded, randomized controlled trial was to evaluate the clinical benefit of routine postoperative X-rays (standard of care) by determining the number of changes made to the treatment plan following assessment of the radiograph obtained after surgical management of fractures of the distal radius and ankle. The hypothesis was that a routine postoperative X-ray is not necessary if standardized intraoperative imaging has been performed.

Methods

This single-center, prospective, randomized controlled, unblinded trial was conducted according to the Declaration of Helsinki and had been approved by the Swiss Ethics Committee North-western and Central Switzerland, approval number 2016–00114. The study was subsequently registered with the German Clinical Trials Registry (DRKS 00011796). The present article was written in accordance with the CONSORT (Consolidated Statement of Reporting Trials) guidelines (13).

Study population

From August 2016 to December 2018, all patients (>18 years of age) who had undergone surgical management of a distal radius or ankle fracture at the certified level 1 trauma center of the Lucerne Cantonal Hospital were screened for the study. The study protocol had been approved before enrolment of the first patient and published separately (14, 15).

Exclusion criteria were: unwillingness/inability to sign the informed consent form, indication for obtaining postoperative computed tomography (CT) at the end of the index procedure, pathological fractures, open fractures (> grade 1 according to Anderson and Gustilo [16]), ipsilateral compartment syndrome, primary arthrodesis or external fixator as definitive treatment, hemiplegia, no intraoperative standardized radiographs available, pregnancy, or patients incapable of participating in outpatient follow-up at six weeks or one year.

A preoperative CT scan was obtained for intra-articular radius fractures to further analyze the fracture pattern based on the four-corner concept (17).

All patients received 2 g intravenous cefazolin as antibiotic prophylaxis before skin incision. The procedures were performed under general or regional anesthesia – all under fluoroscopic control with a medical C arm (Ziehm Imaging, Nuremberg, Germany).

Randomization

Before surgery, patients were assigned to the control or intervention group on a random basis. Randomization was performed using sealed envelopes as simple randomization. Assignment to the control or intervention group was made by the principal investigator in the form of a pictogram affixed to soft drinks; assignment was independent of the type of soft drink chosen (18).

Randomization had to be adjusted after the start of the study because a considerable number of patients in the intervention group (n = 30) had routine postoperative radiographs taken in error in the early study phase. These patients were excluded. Consequently, randomization was converted to adaptive randomization to obtain comparable group sizes. This is also shown in the flow diagram (figure).

Figure.

Flow diagram of the randomized controlled study

Control group

Patients in the control group had standard intraoperative radiographs taken (efigure 1). On the first day after fracture fixation, standardized postoperative radiographs were performed by the radiology department staff. Standard wrist X-rays comprised an anterior-posterior and a lateral view. In patients with an ankle fracture, a lateral image and a mortise view were obtained (efigure 2). Clinical and radiological follow-up was conducted in all patients at six weeks and twelve months.

eFigure 1.

a, b) Anterior-posterior and posterior-anterior radiograph of the wrist with an unobstructed view of the radioulnar joint

c) Lateral view with a 20° radial tilt of the hand for an unobstructed view of the radiocarpal joint, with superimposition of the pisiform, scaphoid and capitate bones

d) Dorsal tangential view (DTV) – the proximal forearm is placed with 75° of inclination to the arm board. The wrist is held in maximum flexion. The dorsal cortex of the distal radius is positioned with 15° of inclination to the vertical X-ray beam.

eFigure 2.

a) Anterior-posterior view of the ankle

b) Mortise view with a clear joint space between the trochlea of talus and tibia/fibula (achieved by internal rotation of the foot by about 20°)

c) Lateral view with overlapping of the medial and lateral margins of the talus and fibula on the posterior third of the tibia

Intervention group

The standard postoperative protocol was modified for patients in the intervention group. On the day after surgery, intraoperative radiographs were assessed by one of the senior surgeons of the Department of Orthopedics and Trauma Surgery and by a senior radiologist. If the quality of intraoperative radiographs, implant position, or reduction was judged to be inadequate, additional imaging (radiographs or CT) was obtained and/or revision surgery was performed. When imaging quality and fracture fixation were adequate, patients were followed-up according to routine postoperative protocol.

Primary study outcome

The primary outcome was the number of changes to the treatment plan, defined as revision surgery or need for additional imaging within six weeks of initial surgery due to inadequate fracture management. It was also considered a change to the treatment plan if the intraoperative radiographs in the intervention group did not meet the specified quality criteria and therefore a postoperative radiograph was subsequently required.

Secondary study outcome

Secondary outcomes were range of motion (ROM) and visual analogue scale (VAS) score for pain in all patients at six weeks. Functional outcome measures were obtained six weeks and one year after surgery. Patients with distal radius fractures completed the Patient-Rated Wrist Evaluation (PRWE), a 15-item questionnaire on functional outcome and associated pain (19). The Foot and Ankle Outcome Score (FAOS) was evaluated for patients with ankle fractures (20).

The following data were also analyzed: gender, age, American Society of Anesthesiologists physical status classification system (ASA score) (21), fracture site, fracture laterality, fracture type (according to the AO/OTA classification), trauma type (high-velocity trauma versus low-energy trauma), seniority of the primary surgeon (departmental head, senior consultant, junior consultant, trainee), number of images obtained during intraoperative imaging, length of hospital stay (days), operating time (minutes), and number of (unscheduled) outpatient visits.

Sample size

The sample size, for both radius and ankle fractures, was determined based on a retrospective evaluation (15) of the rate of changes to the postoperative treatment plan arising from findings from standard postoperative radiographs in 2014. This evaluation showed that a change in plan was made in about 7.6% of the cases studied. Based on these results, a two-tailed Fisher’s test was performed with a power level of 0.80 and alpha error of 0.05. Sample size was calculated using the G*Power 3.1 software package. Therefore, for this study, the required number of patients for each treatment arm was 158.

Statistical analysis

Statistical analysis was conducted using SPSS version 24 (IBM Corp, Armonk NY, USA). Basic descriptive data were presented as median and interquartile range (IQR). Significance tests were selected depending on data characteristics (Mann-Whitney U test, t test, chi-square test, or Fisher’s exact test). The threshold for significance level was set as p ≤0.05.

Results

Study population

From August 2016 to December 2018, 449 patients with distal radius or ankle fractures with an indication for operative treatment presented at the emergency department of the level 1 trauma center. After applying the exclusion criteria, 361 patients were randomized to the control or intervention group. The clinical follow-up observation period lasted until January 2020. Because of protocol violations, 39 patients were subsequently excluded (30 in the intervention group and nine in the control group). Six further patients were lost to follow-up (two in the intervention group and four in the control group). This left data from 316 patients available for the final analysis (163 in the intervention group, 153 in the control group). The Figure shows the CONSORT flow diagram. Basic patient characteristics for the entire cohort and for each group are presented in Table 1.

Table 1. Basic patient characteristics.

Parameter	Intervention group n = 163	Control group n = 153	p value
Sex (n [%])
Male	61 (37.4)	56 (36.6)	0.88
Female	102 (62.6)	97 (63.4)
Age (years [IQR])	53 (35–67)	54 (42–65)	0.63
ASA score (n [%])
ASA I	87 (53.4)	74 (48.4)	0.67
ASA II	62 (38)	64 (41.8)
ASA III	14 (8.6)	15 (9.8)
Fracture description
Fracture site (n [%]) – radius – ankle	105 (64.4) 58 (35.6)	97 (63.4) 56 (36.6)	0.91
Laterality (n [%]) – left – right	102 (62.6) 61 (37.4)	80 (52.3) 73 (47.7)	0.06
Type of fracture (n [%]) – closed – open	153 (93.9) 10 (6.1)	148 (96.7) 5 (3.3)	0.3
Preoperative parameters
Trauma type (n [%]) – low-energy trauma – high-velocity trauma	132 (81) 31 (19)	116 (75.8) 37 (24.2)	0.27
Multiple injury (ISS ≥ 16) – yes – no	6 (3.7) 157 (96.3)	3 (2) 150 (98)	0.5
Pre-operative CT (n [%]) – yes – no	83 (50.9) 80 (49.1)	70 (45.8) 83 (54.2)	0.4

ASA, American Society of Anesthesiologists Physical Status Classification System;

CT, computed tomography; IQR, interquartile range; ISS, Injury Severity Score

Fracture distribution

Of the 316 patients included, 211 (66.8%) were treated for a radius fracture and 113 (33.2%) for an ankle fracture. The classification of these fractures was comparable in both randomized groups and is shown in Table 2.

Table 2. Fracture distribution pattern.

Fracture type		Intervention groupn = 163	Control groupn = 153	p value*
AO 23 – (n [%])		105 (64.4)	97 (63.4)
A	1	0	2 (5.6)	0.31
	2	18 (51.4)	15 (41.7)
	3	17 (48.6)	19 (52.8)
B	1	2 (14.3)	3 (16.7)	0.45
	2	6 (42.9)	4 (22.2)
	3	6 (42.9)	11 (61.1)
C	1	13 (23.2)	17 (39.5)	0.09
	2	21 (37.5)	17 (39.5)
	3	22 (39.3)	9 (21)
AO 44 – (n [%])		58 (35.6)	56 (36.6)
A	1	3 (50)	1 (50)	0.51
	2	1 (16.7)	1 (50)
	3	2 (33.3)	0
B	1	17 (37.8)	10 (25)	0.2
	2	6 (13.3)	11 (27.5)
	3	22 (48.9)	19 (47.5)
C	1	2 (28.6)	7 (53.8)	0.54
	2	3 (42.9)	4 (30.8)
	3	2 (28.6)	2 (15.4)

* The p-value indicates the distribution of the fracture type within categories A-C according to the AO classification.

AO, Association for Osteosynthesis

Primary study outcome

A change in treatment plan was identified in twelve patients (3.8%). Additional postoperative imaging was obtained in eleven patients (3.5%), six of whom (1.9%) underwent revision surgery. One patient in the intervention group underwent revision surgery without additional postoperative imaging, resulting in a reoperation rate of 2.2% (seven patients).

Of the 12 patients with a change to treatment plan, four patients (2.6%) were in the control group and eight (4.9%) were in the intervention group, resulting in no statistically significant difference (p = 0.38) for this endpoint. Furthermore, there was no difference between the fracture sites of these twelve patients—six had a radius fracture (3%) and six had an ankle fracture (5.3%) (p = 0.36).

A complete overview is presented in Table 3 and a case-by-case analysis in eTable 1.

Table 3. Endpoint overview.

	Total	Control group	Intervention group	Distribution difference [95% confidence interval]
Primary endpoint reached	12	4	8	4 (33 % [8.3; 58.3])
Additional imaging studies without further consequence	2	0	2	2 (100 % [100; 100])
Additional computed tomography (CT)	9	3	6	3 (33 % [0; 66.7])
Additional CT without further consequence	3	1	2	1 (33 % [0; 75])
Additional CT + revision surgery	6	2	4	2 (33 % [0; 66.7])
Revision surgery without additional imaging	1	1	0	1 (100 % [100; 100])
Revision surgery	7	3	4	1 (14,3 % [0; 75])

eTable 1. Endpoint – case by case.

Case	1	2	3	4	5	6	7	8	9	10	11	12
Patient
Age (years)	48	28	26	52	31	28	32	69	90	68	83	38
Sex	M	M	M	F	F	M	M	F	F	F	F	F
ASA classification	1	1	1	2	1	1	1	2	2	3	3	1
Randomization*1	1	1	1	1	1	1	2	2	2	1	2	1
Fracture site	Radius	Ankle	Ankle	Ankle	Radius	Ankle	Ankle	Radius	Radius	Radius	Radius	Ankle
AO classification	23-C2	44-C3	44-C1	44-B1	23-C1	44-C1	44-B3	23-B2	23-C1	23-C3	23-C2	44-B3
Primary endpoint
Endpoint reached during stay in hospital	yes	yes	yes	yes	yes	yes	yes	yes	yes	no	no	yes
Endpoint reached after stay in hospital	no	no	no	no	no	no	no	no	no	yes	yes	no
Additional imaging	no	no	no	yes	no	no	no	yes	yes	no	no	yes
Additional computed tomography	yes	yes	yes	no	yes	yes	yes	no	yes	yes	yes	no
Revision surgery	yes	no	yes	no	yes	no	yes	yes	no	yes	yes	no
Reason for reaching endpoint*2	1	2	2	3	1	2	2	4	1	5	5	6

*¹ randomization of the groups (1 = without postoperative radiograph; 2 = with postoperative radiograph)

*² reasons for reaching endpoint: 1 = strong suspicion of intra-articular screw on the intraoperative radiography; 2 = strong suspicion of inappropriately reduced syndesmosis;

3 = inadequate intraoperative radiographs; 4 = inadequate fracture reduction; 5 = secondary dislocation revealed following increased pain in patient 10 and discovered by chance in patient 11 on a routine radiography during outpatient follow-up at six weeks; 6 = extra radiograph following severe postoperative pain

AO, Association for Osteosynthesis; ASA, American Society of Anesthesiologists

Secondary study outcome

Operating time, number of intraoperative radiographs, number of (unscheduled) outpatient visits, surgeon experience, and length of hospital stay were comparable in the two groups (etable 2).

eTable 2. Secondary endpoint analysis.

Parameter	Intervention group n = 163	Control group n = 153	p value
Surgeon (n [%]) – Head surgeon; departmental head – Senior consultant – Junior consultant − Trainee	20 (12.3) 49 (30.1) 50 (30.7) 44 (27)	9 (5.9) 39 (25.5) 56 (36.6) 49 (32)	0.13
Intra-operative radiographs (n [IQR])	4 (3–6)	4 (3–6)	0.76
Hospitalization time (days [IQR])	4 (3–8)	4 (2–9)	0.41
Operating time (minutes [IQR])	110 (81–138)	105 (82–154)	0.97
Unscheduled outpatient consultations (n [%])	7 (4.3)	10 (6.6)	0.46

IQR, interquartile range

The median VAS score for pain was 1 in both groups and demonstrated no relevant difference. Range of motion and functional outcome scores (PRWE, FAOS) were comparable in both groups for both ankle and radius fractures. Analyses of secondary outcomes at six weeks and one year were comparable. All secondary endpoints are listed in eTable 3.

eTable 3. Functional outcomes, range of motion and pain score after six-week and one-year follow-ups.

Parameter	Intervention group n = 163	Control group n = 153	p value
Six-week follow-up
VAS (score [IQR])	1 (1–2)	1 (1)	0.59
Range of motion Wrist (degrees [IQR]) – dorsal extension – palmar flexion – radial abduction – ulnar abduction – supination – pronation	30 (20–40) 30 (20–40) 12.5 (10–20) 20 (10–30) 70 (40–80) 80 (50–90)	30 (10–45) 30 (20–40) 10 (5–20) 15 (10–25) 65 (33.75–80) 80 (57.5–90)	0.62 0.75 0.39 0.15 0.73 0.68
Range of motion Ankle (degrees [IQR]) – dorsal extension – plantar flexion – internal rotation – external rotation	5 (0–10) 25 (15–40) 5 (1.5–16.25) 5 (4.5–11.25)	5 (5–10) 30 (20–30) 10 (5–17.5) 5 (0–10)	0.31 0.7 0.73 0.53
PRWE (score [IQR])	39.5 (26–59.8)	43.4 (26.1–61.3)	0.94
FAOS (score [IQR]) – FAOS symptoms – FAOS pain – FAOS activities of daily living – FAOS sport – FAOS quality of life	36 (12.5–55.5) 41.7 (11.5–68.1) 54.4 (18–67.8) 19 (11.3–43.8) 18.8 (11.3–43.8)	14.5 (9.3–53.6) 25 (11–66.7) 43.1 (22.3–64.7) 20 (25–20) 14 (11–37.6)	0.27 0.71 0.45 0.75 0.78
One-year follow-up
PRWE (score [IQR])	2 (0–7.8)	2 (0–10)	0.51
FAOS (score [IQR]) – FAOS symptoms – FAOS pain – FAOS activities of daily living – FAOS sport – FAOS quality of life	100 (56.3–100) 100 (100) 100 (100) 80 (65–95) 100 (70–100)	100 (72.8–100) 100 (87.5–100) 100 (100) 90 (65–100) 100 (50–100)	0.63 0.34 0.68 0.27 0.61

FAOS, Foot and Ankle Outcome Score; IQR, interquartile range, PRWE, Patient Rated Wrist Evaluation;

VAS, visual analogue scale

Discussion

This single-center, prospective, randomized controlled trial demonstrates that routine postoperative X-rays after fixation of distal radius and ankle fractures can be dispensed with if standardized intraoperative radiographs are obtained. Routine postoperative radiographs neither alter the treatment plan nor affect clinical outcome.

Postoperative X-rays are usually obtained as part of the standard postoperative examinations after fracture fixation. The postoperative “follow-up” radiograph is expected to provide additional information about the reduction and fixation of a fracture using standardized images. By establishing criteria for good intraoperative images and providing the treating surgeons with appropriate training, the potential risk of bias from suboptimal images can be reduced. This is a precondition if routine postoperative X-rays are to be safely dispensed with. Some trauma surgeons argue that these radiographs are necessary in order to ensure adequate comparison during the follow-up period, while also referring to the aspect of legal protection (22). It appears that 90% of surgeons would not reduce the number of postoperative follow-up X-rays purely for economic reasons (23). Indeed, previous studies have also shown that postoperative radiographs obtained immediately after surgical reduction and fixation do not provide any additional information (24, 25). Similarly, our results show that with standardized intraoperative X-rays, routine postoperative radiography can be omitted without compromising the quality of medical care.

Interestingly, van Gerven et al. found that up to three out of four trauma surgeons would reduce the number of routine radiographs during follow-up of surgically treated radius and ankle fractures if high-quality data supported such follow-up protocols (26).

The Warrior study sought to develop a standard protocol for outpatient follow-up of trauma patients with distal radius fractures. Although surgically treated radius fractures were underrepresented in this multicenter, prospective, randomized controlled study, the authors concluded that if adequate radiographs had been obtained during the two-week follow-up after open reduction and internal fixation, no additional imaging was required during further follow-up (3). This is consistent with the results of the present study, with the only difference being the timing of follow-up. Based on these two studies, we believe that a more cost-conscious follow-up protocol with lower radiation exposure is necessary and feasible. If standard intraoperative X-rays are obtained and the patient has an unremarkable clinical course, no further radiographs are required for up to six weeks after surgery.

Furthermore, a routine postoperative radiograph does not help reassure the patient. Given the comparable number of unscheduled or emergency outpatient appointments in both groups, patients appeared to feel equally confident with or without routine postoperative radiographs. Thus, we conclude that a routine postoperative X-ray does not contribute to the subjectively perceived quality of medical care.

However, there are some limitations to this study. Firstly, the originally calculated number of patients needed was based on the assumption that the treatment plan would be changed as a result of the standard postoperative radiograph in 7.2% of cases (15). In this prospective study, the treatment plan was changed in only 3.8% of cases. This could be due to the fact that the intraoperative images required for this study were standardized and carefully performed according to the training provided in the above-mentioned study. This may have resulted in problems such as incorrect screw length or inadequate fracture reduction being identified and corrected during the index procedure rather than after postoperative imaging, thereby decreasing the number of changes to the treatment plan. This was a positive quality improvement effect of the earlier prospective pilot study to improve and demonstrate the need for a standardized intraoperative imaging technique. However, the much smaller number of treatment plan changes in this study also weakens its statistical power.

Secondly, the implementation of a new follow-up protocol in routine clinical practice led to a weakening of adherence to the study protocol. This was evident from the number of patients in the intervention group who mistakenly had a postoperative X-ray (30 patients, 8.4%). This initially led to an imbalance in the number of participants in each group, which was corrected by switching to covariate-adaptive randomization.

Thirdly, the exclusion of patients with open fractures, ipsilateral compartment syndrome, or definitive treatment with an external fixator resulted in a very homogeneous cohort of patients in the present study. However, patients with the above-mentioned conditions do also occur in clinical practice, so the applicability of our data to a selected group of patients may be limited.

Given that a substantial proportion of patients in the intervention group were operated on by the department head or consultants, we are aware that these data may be biased. The department head or consultant was also the person who decided whether the quality of imaging and fracture fixation was adequate enough. This may have resulted in a slightly lower frequency of treatment plan changes in the intervention group.

Conclusions

In conclusion, in the present study postoperative X-rays did not contribute to patient care when routine intraoperative radiographs had been obtained. We advocate the introduction of standards for intraoperative images and the storage of these radiographs at the end of surgery to allow critical, independent assessment.