Trends in the Incidence of Clavicle Fractures and Surgical Repair in Sweden: 2001-2012

Huttunen, Tuomas T. MD, PhD; Launonen, Antti P. MD, PhD; Berg, Hans E. MD, PhD; Lepola, Vesa MD, PhD; Felländer-Tsai, Li MD, PhD; Mattila, Ville M. MD, PhD

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.15.01284
Scientific Articles
Abstract

Background: Clavicle fractures are common injuries causing substantial morbidity. Recent literature suggests that the incidence of surgically treated clavicle fractures has increased. However, it is unknown whether the increase is caused by more surgeons choosing operative over nonoperative treatment for the injury or an increase in the actual incidence of clavicle fractures. The aim of this study was to assess both the national incidence of clavicle fractures and the rate of surgical treatment of those fractures in Sweden.

Methods: We assessed the incidence and trends of clavicle fractures and rates of surgery in Sweden. The validated Swedish Hospital Discharge Register offers a unique opportunity to assess both outpatient and inpatient visits and was used to conduct a national register-based study including all adults (≥18 years of age) with a diagnosis of clavicle fracture in Sweden between 2001 and 2012.

Results: A total of 44,609 clavicle fractures occurred in Sweden between 2001 and 2012. The incidence of clavicle fractures increased from 35.6 per 100,000 person-years in 2001 to 59.3 per 100,000 person-years in 2012. Interestingly, the highest incidence rates were observed in the oldest age groups. The increase in the rate of surgically treated clavicle fractures (705%) was greater than the increase in the actual fracture incidence (67%). Most (77%) of the surgically treated patients were men. Open reduction and plate fixation was the most common surgical procedure. Overall, the proportion of surgically treated clavicle fractures increased markedly.

Conclusions: Although the incidence of clavicle fractures increased in Sweden between 2001 and 2012, the rate of surgical treatment of clavicle fractures increased much more than could be expected solely based on the increase in the fracture incidence. The observed changes in the rates of surgery require additional studies since there is still controversy regarding the indications for surgical treatment.

Author Information

1Department of Anesthesia (T.T.H.) and Division of Orthopedics and Traumatology, Department of Trauma, Musculoskeletal Surgery and Rehabilitation (A.P.L., V.L., and V.M.M.), Tampere University Hospital, Tampere, Finland

2School of Medicine, University of Tampere, Tampere, Finland

3Department of Clinical Science, Intervention and Technology, Karolinska Institutet; Division of Orthopedics and Biotechnology, Karolinska Institutet; and Department of Orthopedics, Karolinska University Hospital Huddinge, Stockholm, Sweden

4Department of Molecular Medicine and Surgery, Section of Orthopedics and Sports Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden

E-mail address for T.T. Huttunen: tuomas.huttunen@uta.fi

Article Outline

There are numerous population-based studies on the epidemiology of clavicle fractures1-5. In a Scottish study, Robinson retrospectively analyzed 1,000 consecutive clavicle fractures and derived an incidence rate of 29 per 100,000 person-years4. In another Scottish study, Court-Brown and Caesar described an incidence rate of 37 clavicle fractures per 100,000 person-years for adults2. A recent North American study by Karl et al. demonstrated an incidence rate of 58 per 100,000 person-years in all groups in a 2009 sample6. It has been estimated that clavicle fractures account for roughly 3% of all adult fractures2,5. Sports injuries are more common causes in younger age groups and simple falls, in older age groups1,3,4. In general, the clavicle fracture distribution curve has been described as bimodal; the first peak in incidence is between the second and third decades of life and the second peak is after 75 years of age2,5.

Clavicle fractures are classified into 3 groups: midshaft, lateral, and medial7, accounting for about 80%, 15%, and 5% of all clavicle fractures, respectively. Various operative techniques have been described in addition to nonoperative treatment. A recent publication by Heuer et al. highlighted the challenges in deciding between operative and nonoperative treatment as the interobserver agreement in treatment preference among 32 orthopaedic surgeons resulted in a moderate kappa value of 0.568.

The most recent Cochrane review9 comparing operative and nonoperative treatment of middle-third clavicle fractures was published in 2013. The systematic review and meta-analysis included 4 randomized controlled trials (RCTs) that compared plate fixation with nonoperative treatment and 4 RCTs comparing intramedullary nailing with nonoperative treatment9. The conclusion was that there were no clinically relevant or statistically significant differences in Constant scores between the treatments after 1 year9. However, it has been also suggested that some patients with a completely displaced midshaft clavicle fracture benefit from primary surgical fixation in terms of an earlier return to work or sports and a lower nonunion rate10-12.

As described in a recent study, operative treatment has gained popularity in Finland13. However, as outpatient visits are not recorded in the Finnish National Hospital Discharge Register, the authors of the study were unable to determine whether operative treatment was increasing because more surgeons were choosing operative over nonoperative treatment for the injury or because the actual fracture incidence was increasing13. As both outpatient treatment and inpatient treatment are recorded in the Swedish Hospital Discharge Register (SHDR), the purpose of this study was to assess the national incidence of clavicle fractures in Sweden. As suggested by the previous Finnish study, we hypothesized that there had been a marked increase in both fracture incidence and surgical treatment of clavicle fractures in Sweden.

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Materials and Methods

To investigate the national incidence of clavicle fractures we obtained data recorded in the SHDR between 2001 and 2012. All adult patients (≥18 years of age) in the SHDR were included. The Swedish National Board of Health and Welfare established the national register in 1964, and it has included national coverage of inpatient care since 1987 and outpatient visits since 2001. The register has been extensively reviewed and validated14.

Contribution of data to the SHDR is mandatory for all Swedish hospitals, both public and private. The register contains data such as personal identification number, age, sex, domicile of the patient, length of hospital stay, primary and secondary diagnoses, and surgical procedures performed during the hospital stay. Diagnoses in the SHDR have been coded with the International Classification of Diseases, Tenth Revision (ICD-10), starting in 1997. The SHDR has had national coverage of medical health care (>99%) since 1987. Day surgery has been included in the register since 1997 and outpatient visits, since 2001. The register undergoes routine validity checks by the Swedish National Board of Health and Welfare, and it has been estimated that <1% of the records on somatic care are missing data on diagnosis14.

The main outcome measure in this study was the number of patients who were treated for a clavicle fracture in the hospital or as outpatients (ICD-10 code S42.0, S42.00, or S42.01) in Sweden between 2001 and 2012. The secondary outcome measure was the number of surgically treated patients who had a clavicle fracture as the primary or secondary diagnosis. Surgical procedures were assessed using procedural coding according to a Swedish version of the NOMESCO (Nordic Medico-Statistical Committee) classification. Procedural codes used included external fixation (NBJ29), fixation with biodegradable implant (NBJ39), wire fixation (NBJ49), intramedullary nailing (NBJ59), plate fixation (NBJ69), screw fixation (NBJ79), combination surgery (NBJ89), and other fracture surgery (NBJ99). When a patient had undergone multiple hospitalizations, we included only the first one because we were not able to reliably differentiate whether the rehospitalization was due to a new fracture in the contralateral clavicle or a complication such as a new fracture in the original clavicle. Only de-identified register data were used in this study. Ethics approval was obtained from the Regional Ethics Committee of Stockholm (Dnr 2013/5:6).

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Statistical Analysis

To calculate the incidence rates of clavicle fractures and of surgically treated clavicle fractures, the annual population data were obtained from the Official Statistics of Sweden (OSS). The OSS maintains an electronic national register of the population of Sweden. The resulting rates (per 100,000 person-years) are based on the results in the entire adult population of Sweden rather than being cohort-based or sample-based estimates; thus, 95% confidence intervals were not calculated and no other statistical estimation methods were used. Statistical analysis was performed using SPSS 22.0 software (IBM).

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Results

A total of 44,609 clavicle fractures were identified in Sweden between 2001 and 2012. The number of clavicle fractures was greater in men (n = 28,516, 64%) than in women (n = 16,093, 36%). There were 2,480 clavicle fractures in 2001 and 4,525 in 2012. The mean age at the time of injury was 45 years for men and 62 years for women. The mean age of all patients at the time of the injury remained very similar between 2001 and 2012 (52 versus 51 years), but there was a difference in the mean age of patients according to treatment modality (surgical versus conservative) and sex. The mean age of surgically treated women decreased from 61.7 years in 2001 to 48.6 years in 2012 whereas the mean age of conservatively treated women increased from 61.7 to 63.2 years. There were no marked changes in the ages of the men.

The incidence of clavicle fracture was 45.1 per 100,000 person-years in 2001 and 76.5 per 100,000 person-years in 2012 for men and 26.4 per 100,000 person-years in 2001 and 42.5 per 100,000 person-years in 2012 for women. The overall incidence of clavicle fractures increased from 35.6 per 100,000 person-years in 2001 to 59.3 per 100,000 person-years in 2012. The increase was evident in all age groups (Figs. 1 and 2). The highest incidences were seen in women 70 years of age and older. The greatest relative increase in incidence occurred in 50 to 59-year-old women, for whom the incidence doubled from 18.8 per 100,000 person-years in 2001 to 38.3 per 100,000 person-years in 2012 (Fig. 2).

The relative increase in the rate of surgery exceeded the increase in the incidence of clavicle fractures (Fig. 3). The proportion of clavicle fractures treated with surgery increased during the study period, from 2.5% of all clavicle fractures in 2001 to 12.1% in 2012. Surgical treatment was more common in men.

Between 2001 and 2012, there were 3,518 surgically treated clavicle fractures, 2,725 (77%) of which were in men and 793 (23%) of which were in women. Plate fixation was the most commonly used surgical technique (n = 2,928) followed by intramedullary nailing (n = 273), combination surgery (n = 129), and pinning (n = 86). The number of fractures fixed with screws alone or with biodegradable implants was low. There was a clear increase in the rate of surgical treatment during the study period, and surgical treatment was more common in the younger age groups (Fig. 4). Between 2001 and 2012, the rate of surgical treatment increased 705% overall, 780% in men, and 505% in women.

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Discussion

To our knowledge, this is the first study describing a population-based national incidence of clavicle fracture. The main finding of our study was that between 2001 and 2012 the incidence of clavicle fracture increased in both men (from 45.1 to 76.5 per 100,000 person-years) and women (from 26.4 to 42.5 per 100,000 person-years). In total, the incidence of clavicle fracture increased by two-thirds: from 35.6 to 59.3 per 100,000 person-years. The rate of surgical treatment increased even more than the fracture incidence did. However, nearly 90% of clavicle fractures were still treated without surgery.

Both Nordqvist and Petersson1 and Nowak et al.3 reported slightly higher total incidence rates of clavicle fractures in Sweden. However, their studies were based on smaller patient samples and differed from the current study by also including children. Taking this into account, our current results are well in line with previously reported rates of the clavicle fracture incidence in Sweden. The results are also very close to other reported incidences in Scotland, England, and the U.S2,4-6. It seems, on the basis of the current study, that a major reason for the increasing incidence of clavicle fractures is an increase in these injuries in older age groups, especially older women. The mean age at the time of injury was 45 years for men and 62 years for women. The increased rates of injuries in older groups may be caused by the more active lifestyles of middle-aged and older people today but may also be an indication of frailty, although the incidence of osteoporotic fractures has been suggested to have reached a plateau in Sweden15,16. The finding of an increased risk among elderly women needs further research in other Western populations. Even though the number of fractures in patients 70 years of age and older was lower than that in the younger age groups, the age-adjusted incidence rate rose even higher in that age group than it did in young men, who are typically active and often participate in high-energy sports and other activities. We also showed that the proportion of surgically treated clavicle fractures has increased substantially. However, the increase in the rate of surgical treatment appears to be attributable to the younger age groups, given that the mean age of both men and women who underwent surgical treatment decreased between 2001 and 2012. This change was greater for women.

In a previous study from Finland, data had been recorded only for hospitalized patients, thereby excluding fractures treated on an outpatient basis13. The authors of that study were therefore unable to show whether the increase in surgical treatment was due to an increase in the rate of clavicle fracture or whether Finnish surgeons were more likely to select surgical treatment17. In Sweden, the rate of surgery increased markedly during the study period, from 0.9 per 100,000 person-years in 2001 to 7.2 per 100,000 person-years in 2012. This finding is interesting as the rate of surgical treatment in the neighboring country of Finland was 8.4 per 100,000 person-years in 2001 and 10.8 per 100,000 person-years in 201013. Thus, it seems that Swedish surgeons were previously more conservative in treating clavicle fractures. The more conservative treatment approach of the Swedish orthopaedic surgeons compared with their Finnish colleagues has been previously reported, with rates of arthroscopy for degenerative knee disease18 and of surgery for Achilles tendon rupture also lower in Sweden19 than in Finland20. However, the rate of clavicle surgery is converging with the rate in Finland. The results of the current study indicate that only a small part of the increase in surgical activity is due to the rise in clavicle fracture incidence. Sweden and Finland are neighboring countries that have similar climates, demographics, and lifestyles so the fracture incidences would be expected to be somewhat similar.

Although controversial, the availability of modern implants and more active patients with greater demands certainly affect our decision-making in the clinical setting. In a multicenter RCT by the Canadian Orthopaedic Trauma Society comparing surgical and conservative treatment of completely displaced clavicle fractures, there was, at 1 year, a statistically significant and almost clinically relevant difference of 10 points in the Disabilities of the Arm, Shoulder and Hand (DASH) score favoring operative treatment12. In another RCT, Virtanen and coworkers found no clinically relevant or statistically significant difference between the results of surgical and conservative treatment of completely displaced clavicle fractures11. Robinson et al. reported similar findings; surgical treatment yielded statistically but not clinically better outcomes in the DASH score but with 4 times the cost of conservative treatment10. However, these trials, and the systematic reviews by Rehn et al.21 and Virtanen et al.22, suggest that surgical treatment of completely displaced clavicle fractures produces a lower nonunion rate, a reduced time to recovery, and a faster return to work or sports. These findings may support surgical treatment of young, active patients who need to return to their previous level of activity in the shortest possible time and may be considered to justify the increased rate of operatively treated patients of up to 12%. On the other hand, high-quality evidence that surgery produces superior long-term results compared with nonoperative treatment remains lacking. Additional large-scale studies, including systematic reviews and meta-analyses, may offer additional insight into the optimal treatment of clavicle fractures11.

The strength of the current study is that it was based on national data on both outpatient and inpatient treatment of clavicle fractures in Sweden. Thus, the reported incidences represent the total rates of clavicle fracture in Sweden. The SHDR has been extensively studied and validated, with the quality of the data found to be excellent14. A clear limitation of this study is that the current version of the ICD does not allow coding of clavicle fracture diagnoses according to the affected anatomical site (e.g., lateral, shaft, or medial). Therefore, we were unable to report the distribution of fractures according to the location in the clavicle. Another limitation is that the SHDR does not reliably include subsidiary diagnoses such as diabetes, malignant tumor, or other chronic conditions that could be used to assess different risk factors underlying clavicle fractures.

In conclusion, there was a marked increase in the incidence of clavicle fractures in Sweden between 2001 and 2012 but the rate of surgical treatment of these fractures increased much more than could be expected solely based on the increase in the fracture incidence. Additional studies on the indications for surgical treatment are needed to clarify the overall 705% increase in surgical treatment of clavicle fractures and also the observed sex differences regarding the choice of a surgical or conservative approach.

Investigation performed at Tampere University Hospital, Tampere, Finland

Disclosure: This study was financially supported by the Competitive State Research Financing of the Expert Responsibility Area of Tampere University Hospital, Tampere, Finland, and research grants from the Stockholm County Council. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work.

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