Abstract
Aims
Recent studies of nonoperatively treated displaced midshaft clavicular fractures have shown a high incidence of nonunion and unsatisfactory functional outcome. Some studies have shown superior functional results and higher rates of healing following operative treatment. The aim of this study was to compare the outcome in these patients after nonoperative management with those treated with fixation.
Patients and Methods
In a multicentre, parallel randomized controlled trial, 146 adult patients with an acute displaced fracture of the midthird of the clavicle were randomized to either nonoperative treatment with a sling (71, 55 men and 16 women with a mean age of 39 years, 18 to 60) or fixation with a pre-contoured plate and locking screws (75, 64 men and 11 women with a mean age of 40 years, 18 to 60). Outcome was assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) Score, the Constant Score, and radiographical evidence of union. Patients were followed for one year.
Results
A total of 60 patients in the nonoperative group and 64 in the operative group completed one-year follow-up. At three months’ follow-up, both the median DASH (1.7 vs 8.3) and median Constant scores (97 vs 90) were significantly better in the operated group (both p = 0.02). After six months and one year, there was no difference in the median DASH or Constant scores. The rate of nonunion was lower in the operative group (2 vs 11 patients, p < 0.02). Nine patients in the nonoperative group underwent surgery for nonunion. The plate was subsequently removed in 16 patients (25%). One patient had a new fracture after removal of the plate and one underwent revision surgery for failure of fixation.
Conclusion
Fixation of a displaced midshaft clavicular fracture using a pre-contoured plate and locking screws results in faster functional recovery and a higher rate of union compared with nonoperative management, but the function of the shoulder is equal after six months and at one year.
Cite this article: Bone Joint J 2018;100-B:1385–91.
Take home message
Osteosynthesis of displaced midshaft clavicular fractures results in higher union rates and faster functional recovery compared with nonoperative treatment.
There is no long-term difference in functional outcome.
Osteosynthesis effectively reduces the risk of nonunion with a number-needed-to-treat (NNT) of seven.
Comminuted, displaced midshaft clavicular fractures are common.1-5 Early papers reported a low incidence of nonunion and high satisfaction following nonoperative treatment.3,4,6 Accordingly, the routine treatment has been nonoperative, regardless of displacement. Studies of nonoperatively treated displaced midshaft clavicular fractures, however, have shown a high incidence of nonunion and unsatisfactory functional outcome,2,7,8 and some have shown superior results with higher rates of healing following operative treatment.9,10
Our aim in this multicentre, randomized controlled trial was to compare the function of the shoulder and rate of nonunion after nonoperative treatment of a comminuted displaced midshaft clavicular fracture with fixation using a pre-contoured plate and locking screws. The null hypothesis was that operative treatment does not provide better functional outcomes or a reduced risk of nonunion in these patients.
Patients and Methods
This Danish multicentre trial was conducted at Aalborg University Hospital, Viborg Regional Hospital and Randers Regional Hospital, which together serve a population of approximately one million. Between February 2010 and May 2014, patients with an acute displaced midclavicular fracture who were treated in the emergency departments of one of the three hospitals were evaluated for inclusion in the study. The inclusion criteria were patients aged between 18 and 60 years with a displaced midclavicular who provided informed consent. A displaced fracture was defined as a fracture with no contact between the ends of the bone at the fracture site on at least one of two anteroposterior radiographs with a 15° to 30° angle between them in the sagittal plane. Exclusion criteria were: bilateral fractures, impending perforation of the skin, open fracture, neurovascular injury, another fracture in the same limb, pathological fracture, a history of symptoms from the shoulder, previous clavicular fracture, more than two weeks since the injury, cognitive impairment, an inability to follow the protocol of treatment, and contraindications to general anaesthesia or surgery.
After written informed consent was obtained, patients were randomized to either nonoperative or operative treatment using sealed envelopes based on computer-generated randomization, which was stratified by the surgical centre using blocks of ten patients. Each block had an equal allocation to nonoperative and operative treatment. This method of randomization was chosen to ensure an equal distribution of nonoperatively and operatively treated patients at the three centres.
Patients in the nonoperative arm of the study were treated with a sling (Collar’n’Cuff, Mölnlycke Health Care, Sweden) for a maximum of three weeks. They were encouraged to discontinue the sling when they no longer felt it was necessary and to use the arm and shoulder within the limits of pain. No physiotherapy was instituted. Patients with symptomatic radiological nonunion six months after the injury were offered surgical treatment, consisting of debridement, reaming of the medullary canals, and fixation with a plate. Bone graft was used from hypertrophic local bone and from the iliac crest if necessary. This group of patients was analyzed using the intention-to-treat principle.
Those in the operative arm underwent surgery within 14 days of the injury. The operations were undertaken under general anaesthesia accompanied by a single dose of intravenous prophylactic antibiotic by orthopaedic specialists (SLJ, CM, MTV) using a pre-contoured plate and locking screws (Acumed, Hillsboro, Oregon). The skin was incised parallel to the bone and the supraclavicular nerves were identified and preserved if possible. The plate with the best fit was chosen, so that at least three bicortical screws could be placed in each main fragment. The postoperative regimen was identical to that of the non-operatively treated patients.
At six months patients with radiological and clinical significant signs of non-union were offered secondary surgical treatment. This group of patients was analysed after the intention-to-treat principle. Patients with symptomatic hardware, whose fractures were united, were offered removal of the plate six months postoperatively.
Outcome
Patients were examined clinically and radiographically after six weeks and after three, six, and 12 months. The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) score.11 Secondary outcomes were the Constant score12 and radiographical evidence of union. Nonunion was defined as lack of callus formation, persistent fracture lines, and/or sclerotic edges of the bones at the fracture site at six months. The nonunion was regarded as symptomatic if these findings were combined with pain at the fracture site, tenderness and local crepitation. The Constant score was recorded by a specialist nurse; the patients were encouraged not to tell which treatment they had received, and both shoulders were covered by clothes.
Statistical analysis
The sample size was calculated on the basis of a power (1 - β) of 80%, a risk of type I error (α) of 5% and a standard deviation of 20 points for the DASH score. A total of 63 patients were required in each group to demonstrate a clinically relevant ten-point difference in DASH score13 at 12 months. In order to allow for loss to follow-up, the recruitment was increased to 150 patients in total. All statistical analysis was conducted using Stata (version 13.1, Stata Corp, College Station, Texas). Continuous variables were analyzed using Student’s t-test for normally distributed data and Mann–Whitney U test for non-Gaussian distributed data. Categorical variables were tested using chi-squared test or Fisher’s exact test if one value was five or less. A number-needed-to-treat (NNT) analysis was performed to evaluate the effectiveness of surgery in order to avoid nonunion. The level of significance was set at p < 0.05.
Results
A total of 150 patients were enrolled and 75 randomized to each group. Four patients randomized to the nonoperative group withdrew consent after randomization and were excluded. One in the operative treatment group who declined surgery was followed in this group according to the intention-to-treat principle.14,15
A total of 22 patients, 11 in each group, were lost to follow-up. All the data before the time of loss to follow-up were included in the analysis. A total of 60 patients (85%) in the nonoperative group and 65 (85%) in the operative group completed one-year follow-up (Fig. 1).
Fig. 1
Study flow diagram.
The detailed demographics and the morphology of the fracture are shown in Table I.
Table I.
Demographic data and fracture morphology
| Parameter | Nonoperative treatment (n = 71) | Operative treatment (n = 75) |
|---|---|---|
| Mean age, yrs (range) | 39 (18 to 60) | 40 (18 to 60) |
| Age, 18 to 30 yrs vs 31 to 45 yrs vs 46 to 60 yrs, n | 19:30:22 | 19:29:27 |
| Male vs female, n | 55:16 | 64:11 |
| Smoker:non-smoker, n | 16:53 (N/A: 2) | 18:54 (N/A: 3) |
| Shoulder straining work, % | 51 | 42 |
| Fracture at dominant arm, yes:no, n | 29:39 (N/A: 3) | 30:44 (N/A: 1) |
| Non-comminuted:comminuted fracture, n | 20:48 (N/A: 3) | 26:46 (N/A: 3) |
| Shortening category ratio, < 1 cm:1 cm to 2 cm:> 2 cm, n | 20:32:16 (N/A: 3) | 18:32:21 |
Functional outcome
At six weeks’ and three months’ follow-up, the mean DASH (p < 0.001 and p = 0.02, respectively; Mann–Whitney U test) and Constant (p < 0.001 and p = 0.02, respectively; Mann–Whitney U test) scores were significantly better in the operated group (p < 0.05). There was, however, no significant difference thereafter (Figs 2 and 3).
Fig. 2
Bar chart showing median Disabilities of the Arm, Shoulder and Hand (DASH) scores during one year of follow-up. At six weeks’ and three months’ follow-up, median scores were significantly better in the operated group (p < 0.001 and p = 0.02, respectively; Mann–Whitney U test). After six months and at one year, there was no difference between the groups. Error bars indicate interquartile ranges.
Fig. 3
Bar chart showing median Constant scores. At six weeks’ and three months’ follow-up, the median scores were significantly better in the operated group (p < 0.001 and p = 0.02, respectively; Mann–Whitney U test). After six months and at one year, there was no significant difference between the groups. Error bars indicate interquartile ranges.
Union of the fracture
A total of 11 patients (17%, 95% confidence interval (CI) 9.1 to 29.1) in the nonoperative group developed nonunion. One was asymptomatic; ten were symptomatic and nine of these were treated with open reduction and plate fixation. One patient, with an aortic aneurysm, did not undergo surgical treatment for nonunion. All surgically treated nonunions had united one year after inclusion in the study.
Two patients (3%, 95% CI 0.0 to 7.1) in the operative group developed a nonunion. The first had initial fixation using only two screws in each main fragment, rather than three, as required in the protocol. Accordingly, revision surgery was undertaken and union obtained. The other nonunion was in the patient who declined operation after randomization, and the nonunion thus should not be regarded as a failure following fixation. Both patients continued in the operative treatment group according to the intention-to-treat principle.14,15
The rate of nonunion was significantly lower in the operated group (p = 0.009, Fisher’s exact test). The relative risk of developing a nonunion after nonoperative treatment compared with operative treatment was 5.7 (95% CI 1.3 to 24.6; p = 0.02), and the number-needed-to-treat (NNT) operatively in order to prevent one nonunion was seven. A per-protocol analysis lowered the rate of nonunion following surgery to 1.5% (95% CI 0.0 to 4.5) and raised this rate following nonoperative treatment to 18.8% (95% CI 10.1 to 30.4). The NNT calculated using per-protocol analysis was six.
The mean DASH scores in the nonoperative group were significantly worse at six months follow-up for those with nonunion compared with those whose fractures united (15.8 vs 2.5, p = 0.02, Mann–Whitney U test). There was no significant difference in the nonoperative group between patients with nonunion and those with union in regard to age, gender, smoking status, and the comminution or displacement of the fracture (Table II).
Table II.
Demographics and morphology of the fracture in the nonoperative group
| Parameter | Union (n = 52) | Nonunion (n = 11) | p-value |
|---|---|---|---|
| Mean age, yrs (range) | 37 (27 to 50) | 41 (36 to 53) | 0.11* |
| Male vs female, n | 40:12 | 8:3 | 0.71† |
| Smoker vs non-smoker, n | 9:43 | 5:6 | 0.05† |
| Comminution vs no Comminution, n | 36:16 | 7:4 | 0.74† |
| Shortening more than 2 cm vs less than 2 cm, n | 12:40 | 3:8 | 0.71† |
-
*
Student’s t-test
-
†
Chi-squared test, or Fisher’s exact test if one value was five or less
Adverse events and complications
A total of 16 patients (25%) in the operative group had the plate removed after six months without complications. One patient had a new fracture four months after removal of the plate. This was medial to the original fracture, independent of previous screw holes, and healed after nonoperative treatment. One patient who had failure of fixation with screws pulling out medially four months postoperatively underwent revision with debridement and further fixation. There were no clinical signs of infection, but perioperative cultures showed Propionibacterium. The fracture united after eight weeks of antibiotic treatment.
At one year, 13 patients (21%) in the nonoperative group and 44 (70%) in the operative group complained of dysaesthesia around and below the fracture site.
Discussion
In this randomized study, we found that operating on patients with a displaced midclavicular fracture reduced the risk of developing nonunion. In the nonoperative group, 11 patients (17%) developed nonunion, which is comparable with previously reported rates.2,9,10,16-19 Previous randomized studies have shown that fixation with a plate reduces the risk of nonunion by a similar factor.9,10,16-19 In the operative group, only two patients (3%) developed nonunion. Although one of these decided against surgical treatment, the patient remained in the operative treatment group in accordance with the intention-to-treat principle.15
The NNT with primary plate fixation in order to prevent one nonunion was seven. For some patients, such a number may appear high considering that a symptomatic nonunion may be treated successfully. There is also a risk of neurovascular complications,20 although surgery for a clavicular fracture generally has a low complication rate.9,10,16-19 Some patients may, however, be willing to expose themselves to the risks of surgery in order to have a quicker recovery and reduce the 1:6 risk of nonunion. In our series, all nine nonunions treated by debridement, plate fixation, and bone grafting healed. A rate of healing of more than 90% may be expected following the surgical treatment of mid-clavicular nonunions.21 It may be possible to reduce the NNT by only operating on those with a high risk of nonunion following nonoperative treatment. We found two statistical models that estimate the risk of nonunion.22,23 These are based on the comminution and displacement of the fracture combined with either age and gender23 or smoking status.22 Based on these parameters, each model gives a probability of nonunion at 24 weeks. These models have not been externally validated. In a newer study, Clement et al24 found that smoking and a DASH score of > 35 points at six weeks following fracture was associated with a high risk of nonunion. We suggest further investigation of the possible benefits of surgery in which only patients at a high risk of nonunion are treated.
One patient in this study developed a deep infection, which resolved after debridement and antibiotic treatment. Including the need for removal of hardware, which was considered in this study to be a complication, 17 patients in the operative group had further surgery due to complications.
Although the branches of the supraclavicular nerve were protected at the time of surgery, many patients in the operative group developed dysaesthesia. Avoiding injury to this nerve, however, can be difficult, as the distribution of its branches varies widely.25 Interestingly, some patients in the nonoperative group also developed dysaesthesia. This may have been due to nerve injury at the time of the initial fracture, or callus formation. Patients were initially examined for neurovascular injury affecting the arm, but not for local dysaesthesia. For patients with a simple uncomminuted fracture, it may be possible to further reduce the risk of complications by using elastic stable intramedullary nailing (ESIN) instead of plating.26 The use of ESIN shows no other advantages compared with plating.27
We found early improvements in functional outcome for patients in the operative group, in whom both DASH and Constant scores improved faster with higher scores at six weeks and three months. This difference was not subsequently maintained, and there were no differences in functional outcome at six and 12 months. Similar findings were reported in a Canadian multicentre study.10 Robinson et al9 also reported improved functional outcomes in patients treated operatively at three months and one year, but no difference in the Constant score at six weeks and six months. Ahrens et al18 more recently also found early improvements in functional outcome for surgically treated patients at six weeks and three months, but no difference at nine months. Woltz et al19 and Virtanen et al16 found no difference in functional outcome at any timepoints. In a recent meta-analysis, Woltz at al28 found a mean difference of 5.1 points in DASH score favouring operative treatment, at 12 months’ follow-up. This difference is not, however, clinically relevant,13 and Woltz et al28 concluded that there is not enough evidence to support routine operative treatment. In the Canadian study,10 nonunions in the nonoperative group were not treated, but were included in the analysis. We found that patients with a nonunion had a poorer functional outcome compared with those whose fractures united, and therefore including untreated nonunions may affect the outcome. Accordingly, Robinson et al9 showed no significant difference in DASH or Constant score at any timepoint after excluding patients with nonunion.
The rate of loss to follow-up in this study was 15%, and similar in both groups. In the worst-case scenario, symptomatic patients in the nonoperative group drop out to seek surgery elsewhere, and patients in the operative group drop out because the outcome is good and they no longer feel the need to be reviewed. Such a scenario may give an overestimation of the functional outcome in the nonoperative group and underestimation in the operative group. Since patients were routinely presented with the option of removal of the plate as a part of the study, there is a risk that this need is overemphasized. Likewise, the nonunions may have been overtreated, and we do not know if symptoms of nonunion may diminish over time and make these patients less likely to seek further attention.
As in multicentre studies, there was a risk of straying from the protocol. The surgical protocol was not adhered to in one patient with failure of fixation and nonunion. If the prescribed technique had been used, it is possible that the fracture would have healed unremarkably, resulting in a lower rate of nonunion in the operative group.
The statistical analysis does not account for potential bias as a result of a clustering effect by clinic. The risk of clustering in this study is believed to be low, as all surgeons had the same level of experience, the number of clinics was low, and data from each clinic included both treatment options.
In the nonoperative group, only 60 patients were available for analysis at follow-up of one year. Our sample size calculation required 63 patients in each group to demonstrate a clinically relevant ten-point difference in DASH score. There is thus a risk of type 2 error in the analysis of DASH scores at one-year follow-up.
In our sample size calculation, we assumed a standard deviation of 20 points. This assumption may be too high, as randomized controlled trials completed after our sample size calculation report a lower standard deviation in DASH score at one-year follow-up.9,16,19 The highest standard deviation in these trials was 13.5, as reported by Virtanen et al.16 Assuming the width of the interquartile range of the 12-month DASH score in our study to be 1.35 times the standard deviation,29 the standard deviation in our study would be 7.9 points. Using a standard deviation of 13.5 points as a worst-case scenario, a new sample size calculation would require only 29 patients in each group. We believe that our initial calculation overestimates the required number of patients and we estimate the risk of type 2 error due to lack of power to be low.
In conclusion, fixation of a displaced midshaft clavicular fracture with a pre-contoured plate and locking screws results in a higher rate of union and faster functional recovery compared with nonoperative treatment, but there is no difference in function after six months and one year. Fixation effectively reduces the risk of nonunion, and routinely operating all these fractures means that seven patients need surgical treatment to avoid one nonunion. We suggest that further studies should be undertaken to identify patients at high risk of developing a nonunion.
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Author contributions:
A. H. Qvist: Acquiring and analyzing the data, Drafting and approving the manuscript.
M. T. Væsel: Acquiring the data, Revising and approving the manuscript.
C. M. Jensen: Designing the study, Acquiring the data, Revising and approving the manuscript.
S. L. Jensen: Designing the study, Acquiring and analyzing the data, Revising and approving the manuscript.
Funding statement:
This study received funding from Swemac Orthopaedics Aps.ClinicalTrials.gov Identifier: NCT01078480.
Although none of the authors has received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article, benefits have been or will be received but will be directed solely to a research fund, foundation, educational institution, or other non-profit organization with which one or more of the authors are associated.
Acknowledgements
The authors would like to acknowledge Ulla Hornum and Andrea Søe-Larsen for their contribution to this study.
This article was primary edited by J. Scott.
