 TRAUMA

Changes in the pattern of fractures of the hip in patients 60 years of age and older between 2001 and 2010 A RADIOLOGICAL REVIEW D. Lakstein, D. Hendel, Y. Haimovich, Z. Feldbrin From E. Wolfson Medical Center, Holon, Israel

The purpose of this study was to identify changing trends in the pattern of distribution of the type and demographics of fractures of the hip in the elderly between 2001 and 2010. A retrospective cross-sectional comparison was conducted between 179 fractures of the hip treated in 2001, 357 treated in 2006 and 454 treated in 2010. Patients aged < 60 years and those with pathological and peri-prosthetic fractures were excluded. Fractures were classified as stable extracapsular, unstable extracapsular or intracapsular fractures. The mean age of the 179 patients (132 women (73.7%)) treated in 2001 was 80.8 years (60 to 96), 81.8 years (61 to 101) in the 357 patients (251 women (70.3%)) treated in 2006 and 82.0 years (61 to 102) in the 454 patients (321 women (70.1%)) treated in 2010 (p = 0.17). There was no difference in the gender distribution between the three study years (p = 0.68). The main finding was a steep rise in the proportion of unstable peritrochanteric fractures. The proportion of unstable extracapsular fractures was 32% (n = 57) in 2001, 35% (n = 125) in 2006 and 45% (n = 204) in 2010 (p < 0.001). This increase was not significant in patients aged between 60 and 69 years (p = 0.84), marginally significant in those aged between 70 and 79 years (p = 0.04) and very significant in those aged > 80 years (p < 0.001). The proportion of intracapsular fractures did not change (p = 0.94). At present, we face not only an increasing number of fractures of the hip, but more demanding and complex fractures in older patients than a decade ago. This study does not provide an explanation for this change. Cite this article: Bone Joint J 2013;95-B:???–???.

 D. Lakstein, MD, Orthopaedic Surgeon, Senior Lecturer  D. Hendel, MD, Orthopaedic Surgeon, Associate Professor  Y. Haimovich, MD, Orthopaedic Surgeon  Z. Feldbrin, MD, Orthopaedic Surgeon, Lecturer E. Wolfson Medical Center, Orthopaedic Department, Holon 58100, Israel. Correspondence should be sent to Dr D. Lakstein; e-mail: [email protected] ©2013 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.95B9. 31752 $2.00 Bone Joint J 2013;95-B:–. Received 31 January 2013; Accepted after revision 23 May 2013

Fractures of the hip in the elderly represent a substantial portion of the overall orthopaedic workload, with an exponential increase of incidence and economic strain on society during the last few years.1 While the distinction between intra- and extracapsular fractures as separate entities with different prognoses and treatment strategies is generally agreed,2,3 the definition of various patterns and subtypes of fractures of the hip is not as clear. For practical purposes, intracapsular fractures may be classified as displaced or undisplaced.4,5 The established prognostic implications of displacement guide treatment.2,6 Several classification systems of extracapsular fractures have been described,7-9 but none has gained predominance as a guide to treatment. However, higher rates of complication have been demonstrated for fractures classified as unstable.10 The different types and patterns of fractures of the hip require specific surgical treatment and have their own prognoses.2,6,10 Surgical techniques and available technologies continue to evolve, along with a multidisciplinary

VOL. 95-B, No. 9, SEPTEMBER 2013

approach to the prevention of these fractures. Bone health and osteoporosis were a priority during the recent Bone and Joint Decade.11,12 The purpose of this study was to identify trends in the distribution of various types of fracture of the hip in the elderly and their complexity during the last decade (2001 to 2010).

Patients and Methods A retrospective comparison of fractures of the hip that were treated during the years of 2001, 2006 and 2010 was conducted. All patients were treated in one university-affiliated hospital serving a population of 500 000. The study had ethical approval and patients were enrolled without consent being obtained. Information was obtained from the Orthopaedic Department’s surgical records (manual records for 2001 and computer database in 2006 and 2010). Radiographs of all patients with the diagnosis of a femoral fracture were reviewed. Those with a fracture of the femoral neck or a peritrochanteric or subtrochanteric fracture were included. Subtrochanteric fractures were defined by the region between the lower margin 1

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D. LAKSTEIN, D. HENDEL, Y. HAIMOVICH, Z. FELDBRIN

Table I. Patient and fracture characteristics Year Characteristics

2001

2006

2010

p-value

Patients (n) Female (n, %)

179 132 (73.7)

357 251 (70.3)

454 321 (70.7)

0.68

Mean age (yrs) (range) Extracapsular (types A + B) Intracapsular (type C)

80.8 (60 to 96) 80.9 (60 to 96) 80.5 (60 to 93)

81.8 (61 to 101) 81.8 (61 to 97) 81.2 (62 to 101)

82.0 (61 to 102) 82.5 (61 to 102) 81.3 (61 to 98)

0.17 0.165 0.81

Fracture type (n, %) A – stable extracapsular A1 – undisplaced A2 – displaced

56 (31.3) 9 (5.0) 47 (26.3)

98 (27.5) 22 (6.2) 76 (21.3)

85 (18.7) 20 (4.4) 65 (14.3)

< 0.001

B – unstable extracapsular B1 – unstable peritrochanteric B2 – reverse obliquity B3 – other subtrochanteric

57 (31.8) 44 (24.6) 9 (5.0) 4 (2.2)

125 (35.0) 91 (25.5) 23 (6.4) 11 (3.1)

204 (44.9) 154 (33.9) 34 (7.5) 16 (3.5)

< 0.001

C – intracapsular C1 – undisplaced C2 – displaced

66 (36.9) 14 (7.8) 52 (29.1)

134 (37.5) 34 (9.5) 100 (28.0)

165 (36.3) 19 (4.2) 146 (32.2)

0.94

of the lesser trochanter and 5 cm distal to it.13 Patients aged < 60 years and those with a pathological (secondary metastatic) or a peri-prosthetic fracture were excluded. During 2001, 399 patients had surgery for a fracture of the hip; the radiographs of 198 could not be found and 22 were excluded, leaving 179 patients (132 women and 47 men) in the study. During 2006, 461 patients had surgery for a fracture of the hip; the radiographs of 78 could not be found and 26 were excluded, leaving 357 patients (251 women and 106 men) in the study. During 2010, 478 patients had surgery for a fracture of the hip; their radiographs were reviewed and 24 were excluded, leaving 454 patients (321 women and 133 men) in the study (Table I). All radiographs were independently reviewed by two of the authors: an orthopedic consultant with extensive experience with hip fractures (DL) and an orthopaedic resident (YH). Inconsistencies in the assessment of the fractures were reconciled by discussion. The fractures were classified based on anteroposterior and lateral radiographs as stable extracapsular (A), unstable extracapsular (B) or intracapsular (C) (Table I). Simple uncomminuted peritrochanteric fractures were considered as stable (type A). Peritrochanteric fractures with comminution of the calcar or lateral cortex were further classified as unstable (B1).14-16 Reversed obliquity fractures were considered unstable (B2). Subtrochanteric fractures, as defined as those whose main fracture line lay between the lesser trochanter and 5 cm distal to it, were classified as B3. Intracapsular fractures were subclassified as undisplaced (C1) or displaced (C2).4,17 Previous studies consistently found good reliability of classifying intertrochanteric fractures as stable or unstable using

the AO16 or Evans’7 classifications.4,15,16 Other studies showed good reliability when classifying intracapsular fractures as displaced or undisplaced.4,17 Our classification originally included a type B4 fracture – atypical bisphosphonate related fractures.18 However, as this study was a radiological study with many of the medical records unavailable to confirm bisphosphonate therapy, and as many atypical fractures occur below the subtrochanteric region as defined here, we decided to include atypical fractures in the subtrochanteric region as type B3 fractures. The age and gender of patients were recorded. The authors chose not to include data about treatment or complications as those would only reflect differences in treatment strategies pursued by the surgeons in our department. Statistical analysis. Statistical analyses were performed using SPSS v19 software (IBM, Armonk, New York). The ages of the patients were compared using one-way analysis of variance (ANOVA). The distribution of gender and type of fracture was analysed with chi-squared testing. Interobserver agreement was quantified using Cohen’s weighted kappa calculation. We considered agreement as poor if < 0.2, fair if between 0.21 and 0.40, moderate if between 0.41 and 0.60, substantial if between 0.61 and 0.80 and good if > 0.80. A p-value < 0.05 was considered to be statistically significant.

Results The weighted kappa analysis of interobserver variability of fracture classification was good (0.85). There was no statistically significant difference between the mean ages of the patients treated in each year (p = 0.17), THE BONE & JOINT JOURNAL

CHANGES IN THE PATTERN OF FRACTURES OF THE HIP IN PATIENTS 60 YEARS OF AGE AND OLDER BETWEEN 2001 AND 2010

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Table II. Incidence of the different types of fracture stratified by years and age groups Age group Year/Fracture type 2001 A B C Total 2006 A B C Total 2010 A B C Total

60 to 60 years

70 to 79 years

80 to 89 years

90 to 102 years

4 5 6 15

17 18 20 55

24 29 35 88

11 5 5 21

6 11 14 31

21 31 34 86

55 67 62 184

16 16 24 56

6 12 17 35

17 51 44 112

50 106 81 237

12 35 23 70

50

Proportion (%)

2001 45

2006

40

2010

45

37

36

32

31 30

38

35

35 27

25 20

remarkable in older patients (p < 0.001 between 80 to 89 years; p = 0.004 aged > 90 years) (Table II). The proportion of intracapsular versus extracapsular fractures was not influenced by age group (p = 0.95, 60 to 69 years; p = 0.15, 70 to 79 years; p = 0.13, 80 to 89 years; p = 0.3, > 90 years).

19

15 10 5 0 A Stable extracapsular

B Unstable extracapsular

C Intracapsular

Fig. 1 Bar chart showing the distribution of type of hip fracture in 2001, 1006 and 2010.

nor when further divided into extracapsular (p = 0.165) and intracapsular fracture types (p = 0.81) (Table I and II). There was also no significant difference in gender distribution of patients between the three study years (p = 0.68) (Table I). The main finding was a steep rise in the proportion of unstable extracapsular fractures during this time (Fig. 1). The number of unstable extracapsular fractures was 57 (32%) in 2001, 125 (35%) in 2006 and 204 (45%) in 2010 (p < 0.001), but the proportion of intracapsular fractures did not change (p = 0.94) (Table I, Fig. 1). Subgroup analysis stratifying patients into four age groups reveals that while the change in the proportion between type A and type B fractures over the years in the youngest age groups was not significant (p = 0.84 between the ages of 60 to 69 years) and marginal in patients in their seventies (p = 0.04), it was VOL. 95-B, No. 9, SEPTEMBER 2013

Discussion A fracture of the hip in the elderly has substantial morbidity and mortality.19 The most important preventable cause of these fractures is the presence of low bone mass.20 Over the last few decades, both the prevention of fractures of the hip and the treatment of osteoporosis have been emphasised, with subsequent increasing attention and awareness, and this formed a focus for the Bone and Joint Decade.11,12 Our comparison of the demographics of fractures of the hip and the pattern of distribution of the types of fracture between 2001 and 2010 demonstrated an increase in their complexity. This increase is not significant in younger patients and marginally significant in septuagenarians but very significant in patients aged > 80 years. This study has several limitations. First, it was based on radiological data, with no clinical data to confirm the mechanism of injury or bone pathology. For 2001, many of the medical records and radiographs could not be retrieved, and the community records including details of bone density measurement and medication were unavailable. In order to include mainly osteoporotic low-energy fractures, patients aged < 60 years and fractures thought to be pathological were excluded. This, of course, did not absolutely eliminate high-energy and pathological fractures from the study. Secondly, about half of the 2001 radiographs and 18% of 2006 radiographs were unavailable. However, lost radiological data were due to problems of storage and may be considered as random, causing no apparent bias. Thirdly, the study was conducted in one hospital and thus, these results may not necessarily reflect the situation for

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D. LAKSTEIN, D. HENDEL, Y. HAIMOVICH, Z. FELDBRIN

Table III. Studies reporting the distribution of stable and unstable extracapsular fractures of the hip Author/s 7

Evans Sernbo and Johnell25 Kyle et al22 Jensen8 Zain Elabdien et al23 Hornby et al24 Sernbo and Johnell25 Bridle et al26 Current study (2001 series) Current study (2010 series)

Year of interest

Patients (n)

Mean age (yrs)

Stable:unstable (%)

Female:male (%)

1949 1950s 1979 1980 1984 1989 1980s 1991 2001 2010

101 970 622 234 127 106 1359 100 179 454

62.2

72:28 - :45 57:42 59:41 28:72 28:72 - :45 41:59 49:40 30:54

76:24 60:40 76:24 75:25 74:26 84:16 74:26 71:29

other groups of patients. Evaluating changes in the incidence of fractures of the hip was not one of the goals of this study. The rise in incidence nationally has been widely established in previous studies.1 The current study showed a constant distribution between intra- and extracapsular fractures, with a little more than a third being intracapsular fractures. However, within the group of extracapsular fractures, the proportion of unstable fractures increased significantly. These unstable extracapsular fractures have previously been demonstrated to have a poorer prognosis and higher rate of complications than stable fractures, including failure of fixation and infection.10,21 Several previous studies have recorded the distribution between stable and unstable fractures during the last seven decades (Table III).7,8,22-26 The definition of stability and the inclusion of subtrochanteric fractures differed between the studies but a slow increase in the incidence of unstable fractures over the years is noticeable. More apparent was the increase in patients' age over the years (Table III). Endogeous factors influence the pattern of the fracture rather than merely the mechanism of injury or chance.25,27,28 This notion is supported by the finding that patients with bilateral hip fractures more often suffered fractures of the same type bilaterally.29,30 Evaluation of the prediction of the risk of a fracture of the hip by morphological parameters estimated from dual energy x-ray absorptiometry in the EPIDOS (Epidémiologie de l’ostéoporose) study demonstrated that the morphology of the proximal femur can influence the risk and the type of fracture that is sustained.31,32 Patients with trochanteric fractures had lower bone mineral density, thinner cortices and a higher buckling ratio, and patients with femoral neck fractures had longer hip axes.31,32 Other studies demonstrated that women with trochanteric fractures tend to be older, shorter and lighter than those with femoral neck fractures. On the other hand, the biomechanics of falling have not been found to be different in the two types of hip fracture.33 Women with trochanteric fractures have more severe and generalised bone loss, especially of the trabecular component, while cervical fractures seem to be more related to pelvic structure.33 Zain Elbdien et al23 demonstrated that 65% to 75% of patients with stable trochanteric fractures

73.4 78.9 81.8 80.8 82.0

had well preserved bone while only 10% to 20% of patients with unstable fractures had well preserved bone. However, these findings relied on radiological measurements of cortical thickness in the thickest diaphyseal portion of the femur and not on more contemporary imaging modalities to assess the quality and morphology of bone. Therefore, changes in the pattern of fractures that were sustained in the population under investigation and hence the prognosis may be influenced by endogenous factors, which may include an increase in patients’ age, changes in the quality of bone and other factors, which remain unclear, such as medical treatment, alterations in lifestyle and nutrition. At the present, in addition to the global increase in the incidence of fracture of the hip, we identified that the proportion of complex fractures is rising. If these changes are not limited to our community, they should be taken into consideration when allocating resources. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first-proof edited by J. Scott.

References 1. Burge R, Dawson-Hughes B, Solomon DH, et al. Incidence and economic burden of osteoporosis-related fractures in the United States, 2005-2025. J Bone Miner Res 2007;3:465–475. 2. Miyamoto RG, Kaplan KM, Levine BR, Egol KA, Zuckerman JD. Surgical management of hip fractures: an evidence-based review of the literature. I: femoral neck fractures. J Am Acad Orthop Surg 2008;16:596–607. 3. Kaplan K, Miyamoto R, Levine BR, Egol KA, Zuckerman JD. Surgical management of hip fractures: an evidence-based review of the literature. II: intertrochanteric fractures. J Am Acad Orthop Surg 2008;16:665–673. 4. Thomsen NO, Jensen CM, Skovgaard N, et al. Observer variation in the radiographic classification of fractures of the neck of the femur using Garden’s system. Int Orthop 1996;20:326–329. 5. Bhandari M, Devereaux PJ, Tornetta P 3rd, et al. Operative management of displaced femoral neck fractures in elderly patients: an international survey. J Bone Joint Surg [Am] 2005;87-A:2122–2130. 6. Barnes R, Brown JT, Garden RS, Nicoll EA. Subcapital fractures of the femur: a prospective review. J Bone Joint Surg [Br] 1976;58-B:2–24. 7. Evans EM. The treatment of trochanteric fractures of the femur. J Bone Joint Surg [Br] 1949;31-B:190–203. 8. Jensen JS. Classification of trochanteric fractures. Acta Orthop Scand 1980;51:803– 810. 9. Müller ME, Nazarian S, Koch P. The comprehensive classification of fractures of the long bones. Berlin: Springer, 1990:120–121. 10. Suckel AA, Dietz K, Wuelker N, Helwig P. Evaluation of complications of three different types of proximal extra-articular femur fractures: differences in complications, age, sex and surviving rates. Int Orthop 2007;31:689–695. THE BONE & JOINT JOURNAL

CHANGES IN THE PATTERN OF FRACTURES OF THE HIP IN PATIENTS 60 YEARS OF AGE AND OLDER BETWEEN 2001 AND 2010

11. Dreinhöfer KE, Féron JM, Herrera A, et al. Orthopaedic surgeons and fragility fractures: a survey by the Bone and Joint Decade and the International Osteoporosis Foundation. J Bone Joint Surg [Br] 2004;86-B:958–961. 12. Dreinhöfer KE, Anderson M, Féron JM, et al. Multinational survey of osteoporotic fracture management. Osteoporos Int 2005;16(Suppl):S44–S53. 13. Loizou CL, McNamara I, Ahmed K, Pryor GA, Parker MJ. Classification of subtrochanteric femoral fractures. Injury 2010;41:739–745. 14. Pervez H, Parker MJ, Pryor GA, Lutchman L, Chirodian N. Classification of trochanteric fracture of the proximal femur: a study of the reliability of current systems. Injury 2002;33:713–715. 15. Jin WJ, Dai LY, Cui YM, et al. Reliability of classification systems for intertrochanteric fractures of the proximal femur in experienced orthopaedic surgeons. Injury 2005;36:858–861. 16. Schipper IB, Steyerberg EW, Castelein RM, et al. Reliability of the AO/ASIF classification for pertrochanteric femoral fractures. Acta Orthop Scand 2001;72:36–41. 17. Frandsen PA, Andersen E, Madsen F, Skjødt T. Garden’s classification of femoral neck fractures: an assessment of inter-observer variation. J Bone Joint Surg [Br] 1988;70-B:588–590. 18. Schilcher J, Michaëlsson K, Aspenberg P. Bisphosphonate use and atypical fractures of the femoral shaft. N Engl J Med 2011;364:1728–1737. 19. Egol KA, Koval KJ, Zuckerman JD. Functional recovery following hip fracture in the elderly. J Orthop Trauma 1997;11:594–599. 20. Riggs BL, Melton LJ 3rd. The prevention and treatment of osteoporosis. N Engl J Med 1992;327:620–627. 21. Audigé L, Hanson B, Swiontkowski MF. Implant related complications in the treatment of unstable intertrochanteric fractures: meta-analysis of dynamic screwplate versus dynamic screw-intramedullary nail devices. Int Orthop 2003;27:197–203. 22. Kyle RF, Gustilo RB, Premer RF. Analysis of six hundred and twenty-two intertrochanteric hip fractures. J Bone Joint Surg [Am] 1979;61-A:216–221.

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23. Zain Elabdien BS, Olerud S, Karlström G. The influence of age on the morphology of trochanteric fracture. Arch Orthop Trauma Surg 1984;103:156–161. 24. Hornby R, Evans JG, Vardon V. Operative or conservative treatment for trochanteric fractures of the femur: a randomised epidemiological trial in elderly patients. J Bone Joint Surg [Br] 1989;71-B:619–623. 25. Sernbo I, Johnell O. Changes in bone mass and fracture type in patients with hip fractures: a comparison between the 1950s and the 1980s in Malmö, Sweden. Clin Orthop Relat Res 1989;238:139–147. 26. Bridle SH, Patel AD, Bircher M, Calvert PT. Fixation of intertrochanteric fractures of the femur: a randomised prospective comparison of the gamma nail and the dynamic hip screw. J Bone Joint Surg [Br] 1991;73-B:330–334. 27. Dretakis EK, Christodoulou NA. Significance of endogenic factors in the location of fractures of the proximal femur. Acta Orthop Scand 1983;54:198–203. 28. Alffram PA. An epidemiologic study of cervical and trochanteric fractures of the femur in an urban population: analysis of 1,664 cases with special reference to etiologic factors. Acta Orthop Scand Suppl 1964;65(Suppl):1–109. 29. Dretakis E, Kritsikis N, Economou K, Christodoulou N. Bilateral non-contemporary fractures of the proximal femur. Acta Orthop Scand 1981;52:227–229. 30. Sawalha S, Parker MJ. Characteristics and outcome in patients sustaining a second contralateral fracture of the hip. J Bone Joint Surg [Br] 2012;94-B:102–106. 31. Szulc P, Duboeuf F, Schott AM, et al. Structural determinants of hip fracture in elderly women: re-analysis of the data from the EPIDOS study. Osteoporos Int 2006;17:231–236. 32. Duboeuf F, Hans D, Schott AM, et al. Different morphometric and densitometric parameters predict cervical and trochanteric hip fracture: the EPIDOS Study. J Bone Miner Res 1997;12:1895–1902. 33. Mautalen CA, Vega EM, Einhorn TA. Are the etiologies of cervical and trochanteric hip fractures different? Bone 1996;18(Suppl):133S–137S.