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Clin Orthop Relat Res. 2009 November; 467(11): 2970–2978.
Published online 2009 April 15. doi:  10.1007/s11999-009-0835-5
PMCID: PMC2758971

Predictors of Prognosis for Elderly Patients with Poststroke Hemiplegia Experiencing Hip Fractures

Abstract

Hip fracture is an important cause of mortality and disability in elderly patients, particularly in those with poststroke hemiplegia, but little information is available regarding differences of general characteristics between patients with and without hemiplegia who experience hip fractures, factors predicting recovery of prefracture ambulatory status, and mortality of patients with poststroke hemiplegia with hip fractures. We retrospectively reviewed 1379 consecutive prospectively followed patients with hip fractures treated from January 2000 to May 2006. Of the 1379 patients, 101 (7.3%) had poststroke hemiplegia. All patients were followed a minimum of 1 year if they survived more than a year or until death if they died within a year after surgery (mean, 19.5 months; range, 4–49 months). According to the American Society of Anesthesiologists (ASA) rating, the patients with hemiplegia were sicker than patients without hemiplegia, more likely to have three or more comorbidities, lower cognitive ability, weaker prefracture ambulatory status, more days of hospitalization, and higher mortality rate. Gender, ASA rating, number of comorbidities, and prefracture ambulatory status predicted mortality of hip fractures in elderly patients with poststroke hemiplegia, and the ASA rating, number of comorbidities, and cognitive ability predicted recovery of prefracture ambulatory status for these patients.

Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Introduction

The proportion of elderly people is increasing in most countries. Sweden has one of the largest proportions of elderly people in the world; 18% are older than 65 years, and by 2010, this figure will have increased to approximately 26% [16]. From 2001 to 2020, China similarly is faced with rapid aging of the population, increasing by 3.28% per year [41]. By 2020, the aging population (at least 60 years of age) will increase to approximately 17.17% [41]. Hip fracture often occurs in the elderly population, and the number of patients with hip fractures is increasing correspondingly with the sustained increase in the elderly population [26], such as in the United States [6, 31] and Asia [23, 25].

Stroke also is a substantial cause of morbidity in the elderly. As with hip fractures, stroke incidence increases with increasing age. In China, the morbidity rate of stroke is 640 per one million and the mortality rate is 66 per one million. Every 40 to 45 seconds, someone in the United States has a stroke [11]. One-fourth of initial stroke survivors have a second stroke within 5 years [21]. Patients who have a stroke are vulnerable for osteoporotic fractures and falls. Increased fracture risk is a recognized complication after a stroke, particularly in patients who have hemiplegia after the stroke [32]. Patients who have had strokes have as much as a fourfold increased risk of hip fracture [36] because of a high incidence of falls [35, 42] and loss of bone mass on the paretic side [14, 37]. In a study of 363,447 patients who had strokes, 4528 patients had hip fractures, 2.0% had fractures by 1 year, and 10.6% had fractures by 10 years [7].

Various factors (eg, age [9, 38], gender [10, 13, 38], ASA rating [9, 17], dementia [4], and type of fracture [28, 29]) reportedly affect ambulatory status and mortality of elderly patients with hip fractures, but little is known of any differences in general characteristics between patients with and without hemiplegia who had hip fractures, factors predicting recovery of prefracture ambulatory status, and mortality of patients with hemiplegia after stroke who experienced hip fractures.

Therefore, the purpose of our study was fourfold: (1) to compare the general characteristics of patients with and without hemiplegia who experienced hip fractures; (2) to identify predictors of mortality of patients with hemiplegia who experienced hip fractures; (3) to identify predictors of recovery of prefracture ambulatory status of patients with hemiplegia who experienced hip fractures; and (4) to identify the relative frequency of fractures in the affected and unaffected sides of patients with hemiplegia.

Materials and Methods

We retrospectively reviewed the medical records of 1505 prospectively followed patients with hip fractures treated between January 2000 and May 2006. Patients were identified at the time of admission and were prospectively followed up. Information regarding prefracture ambulatory status was collected at the time of admission by patient or family member interview. We included patients (1) at least 65 years old with a nonpathologic femoral neck or intertrochanteric hip fracture and having surgical treatment; (2) with followup of at least 1 year after surgery if patients survived more than a year or until death if patients died within a year after surgery; and (3) who survived the perioperative period. We excluded patients who had prior surgery on the same hip or previous ipsilateral hip fracture. Of the 1505 patients, 126 (109 without hemiplegia and 17 with hemiplegia) were excluded by these criteria leaving 1379 patients. Of the 126 patients excluded, 68 were lost to followup, either because we failed to contact patients or the patients refused to be interviewed. Of these 68 patients, 25 dropped out within 6 months after surgery and 43 dropped out between 6 and 12 months after surgery. One hundred one of the 1379 patients (7.3%) had hemiplegia of a lower extremity before hip fracture and 1278 did not have hemiplegia. In the group of 101 patients with hemiplegia, 76 survived at least 1 year. The mean age of all 1278 patients without hemiplegia was 76.4 ± 7.1 years (range, 65–99 years) at the time of injury, and that of the 101 patients with hemiplegia was 76.2 ± 5.8 years (range, 65–89 years) (Table 1). The minimum followup was 4 months (mean, 19.5 months; range, 4–49 months).

Table 1
General characteristics of the patient groups

From the medical records, we abstracted data on fracture type, surgery type, patient’s general health status, severity of health problems at the time of admission, cognitive ability on admission, and days of hospitalization. For patients with poststroke hemiplegia, we recorded whether the fracture occurred on the hemiparetic or on the nonhemiplegic side. Followup information regarding ambulatory status was obtained by clinical or telephone interview. The date of death for patients who died was ascertained from the physician or a relative of the patient.

The patient’s general health status was defined by the number of preoperative comorbidities, including hypertension, stroke, ischemic heart disease, diabetes mellitus, congestive heart failure, cardiac arrhythmias, renal disease, cancer, chronic obstructive pulmonary disease, and the need for ongoing anticoagulation therapy. These comorbidities were chosen as being most important based on our experience and those reported in the literature [10, 44]. A previous study suggests patients with zero, one, or two comorbidities had similar outcomes [1]. Therefore, for this analysis, patients were categorized as having two or fewer or three or more comorbidities.

The ASA rating scale was used to assess the role of the severity of health problems at the time of admission. The categories are: I, normal, healthy; II, mild systemic disease; III, severe systemic disease, not incapacitating; IV, severe incapacitating systemic condition, constant threat to life; and V, moribund patient. There were no patients in Category V in this study. For purposes of statistical analysis, ASA ratings were collapsed into two categories: I or II and III or IV. This approach was used previously [10, 24, 39].

Cognitive ability was rated according to Hasegawa’s Intelligence Scale revised for dementia [15, 30]. A score of 20 or less was considered dementia and a score of 21 or greater was considered nondementia. Dementia was categorized in four levels: 3 = nondementia (score of 21 or greater), 2 = slight dementia (score of 15–20), 1 = moderate dementia (score of 10–14), and 0 = severe dementia (score of 0–9) [15, 17, 30].

All patients were treated with a similar postoperative physiotherapy protocol by a skilled physiatrist. We used a Pelma vein pump (Labtek Medical Co, Dalian City, China) to prevent thrombosis and edema as soon as the operation was completed. Patients began isometric contraction of the quadriceps femoris muscle, active movement, and passive activity of the knee and ankle on the first postoperative day. In 2 to 3 days, they were taken to the rehabilitation unit to begin ambulation using parallel bars. Patients were allowed partial weightbearing on the fractured extremity as tolerated. As soon as they felt secure using the parallel bars, patients were encouraged to use a walker or crutches, depending on their abilities before fracture. When patients felt secure using a walker or crutches, they received gait training. The average lengths of hospitalization were 25 days and 31 days in patients without hemiplegia and with hemiplegia, respectively. After discharge, patients received training in a rehabilitation hospital or outpatient rehabilitation clinic and gradually were allowed full weightbearing using a walker, crutches, or cane, or without assistance. Duration of supervised rehabilitation was 6 months.

We dichotomized postfracture ambulatory status as a return to the prefracture level or a decrease in at least one level of function [39]. Prefracture and postfracture ambulation levels were classified based on standard definitions of community, home, and nonfunctional ambulators [22, 39]. For purposes of a more detailed analysis, these categories were further subdivided (Table 2) [22, 39].

Table 2
Categories of ambulatory status

We compared the general characteristics of the patients with hip fractures with poststroke hemiplegia of the lower extremity with a population without hemiplegia, and investigated predictors of recovery of prefracture ambulatory status and mortality at 1 year followup of elderly patients with poststroke hemiplegia who had a hip fracture. Confounding variables included age, gender, ASA rating, number of preoperative comorbidities, type of fracture, prefracture ambulatory status, cognitive ability, and side of fracture. For continuous variables, we determined the mean ± standard deviation. We performed exploratory analyses to determine differences in the categorical variables (gender, ASA rating, number of preoperative comorbidities, type of fracture, surgery type, prefracture ambulatory status, cognitive ability, 1-year survival status) using contingency table methods (chi square) and differences in continuous variables (age, days of hospitalization) using unpaired two-tailed Student’s test or nonparametric test (Mann-Whitney U test) between patients with and without hemiplegia. We similarly compared the same variables between patients who survived and those who died, and between patients who recovered and those who did not recover prefracture ambulatory status; a p value of 0.05 or less was considered significant. To determine the simultaneous effect of potential confounding variables on dependent variables (mortality, recovery of prefracture ambulatory status), a multiple logistic regression was performed for variables with a p < 0.05 in the preliminary analysis. The data were analyzed using SPSS® Version 16.0 (SPSS Inc, Chicago, IL).

Results

The two groups did not differ in gender ratio, age, type of fracture, or surgery type (prosthetic replacement or internal fixation) (Table 1). The patients with hemiplegia were sicker (p = 0.021) than the patients without hemiplegia according to the ASA rating of preoperative risk, and the former were more likely to have an ASA rating of Category III or IV. Furthermore, there was a difference in the number of preoperative comorbidities between the groups. The patients with hemiplegia were more likely (p = 0.004) to have three or more comorbidities than the patients without hemiplegia. Prefracture ambulatory status was inferior (p < 0.001) in the patients with hemiplegia compared with the patients without hemiplegia, and patients without hemiplegia were more likely to be community ambulators. Patients with hemiplegia were more likely (p < 0.001) to have lower cognitive ability, and they had longer (p < 0.001) mean days of hospitalization (mean rank, 963.59) than patients without hemiplegia (mean rank, 668.38). The mortality rate was higher (p < 0.001) in patients with hemiplegia than in patients without hemiplegia, with 25 (24.8%) patients with and 138 (10.8%) patients without hemiplegia dying within 1 year of hip fracture.

In the preliminary analysis, age (p = 0.677), type of fracture (p = 0.388), and side of fracture (p = 1.00) were similar between the patients who survived and those who died; however, male gender (p < 0.001), higher ASA rating (p < 0.001), more number of preoperative comorbidities (p = 0.001), weaker prefracture ambulatory status (p < 0.001), and lower cognitive ability (p = 0.04) were more likely in patients who died within a year after surgery than in patients who survived (Table 3). In the multiple logistic regression analysis, gender (p = 0.012), ASA rating (p = 0.01), number of preoperative comorbidities (p = 0.03), and prefracture ambulatory status (p < 0.001) predicted mortality of elderly patients with poststroke hemiplegia who experienced hip fractures (Table 4).

Table 3
Comparison of patients’ characteristics 1 year after surgery
Table 4
Predictors of 1-year mortality in the hemiplegic group

To assess return to prefracture ambulatory status, we excluded three of the 76 patients with hemiplegia who were nonfunctional ambulators before experiencing hip fracture, and of the remaining 73 patients, 50 (68.5%) returned to their prefracture ambulatory status, and 23 did not return to their prefracture ambulatory status (Table 5). Of these 23 patients, 15 had decreases of one ambulatory level from their prefracture level, seven had decreases of two ambulatory levels, and one had a decrease of three ambulatory levels. In the preliminary analysis, age (p = 0.133), type of fracture (p = 0.16), prefracture ambulatory status (p = 0.531), and side of fracture (p = 0.306) were similar between the patients who recovered and those who did not recover prefracture ambulatory status. In the multiple logistic regression analysis, ASA rating (p = 0.005), number of preoperative comorbidities (p = 0.021), and cognitive ability (p = 0.006) predicted recovery of prefracture ambulatory status in elderly patients with poststroke hemiplegia who experienced hip fractures (Table 6).

Table 5
Characteristics of recovery status of hemiplegic patients who survived to 1 year
Table 6
Predictors of 1-year recovery of ambulatory status

Eighty-nine hip fractures (88.1%) occurred in patients with hemiplegia and 12 (11.9%) occurred in patients without hemiplegia (Table 3).

Discussion

The proportion of elderly people is increasing worldwide. Hip fractures and strokes often occur in the elderly population and their rates increase with increased age. Patients who have strokes are vulnerable for osteoporotic fractures. Increased fracture risk is a recognized complication after stroke [2, 7, 20], particularly with strokes with resulting hemiplegia [32], but factors predicting recovery of prefracture ambulatory status and mortality for patients with poststroke hemiplegia who experienced hip fractures are not reported, and little information is known regarding differences of general characteristics between patients with or without hemiplegia who have hip fractures. Our purpose was fourfold: (1) to compare the general characteristics of patients with and without hemiplegia who experienced hip fractures; (2) to identify predictors of mortality of patients with hemiplegia who experienced hip fractures; (3) to identify predictors of recovery of prefracture ambulatory status of patients with hemiplegia who experienced hip fractures; and (4) to identify the relative frequency of fractures in the affected and unaffected sides of patients with hemiplegia.

This study has some limitations. The sample size of patients with hemiplegia was relatively small. We lacked information about other factors, such as economic and social factors, that might influence return of function. Also, we did not classify or stage patients who had a stroke. The severity is an important influence on mortality and recovery of function. Hip fracture during an earlier period of stroke rehabilitation results in a more negative influence because the fracture disturbs rehabilitation training, and earlier-period rehabilitation training is more crucial. We did not consider type of surgery as a variable because type of surgery and type of fracture are almost collinear variables [17].

We found patients who had a previous stroke represented 7.3% of all patients, which is similar to a reported percentage [43] (Table 7). Patients who have had a stroke have an increased risk for an osteoporotic hip fracture [36] because of a high frequency of falls [35, 42] and loss of bone mass on the paretic side [14, 18, 19, 33, 37]. Most fractures that occur after a stroke are on the paretic side [3, 34, 43] and are caused by accidental falls [12, 33]. We found 88.1% of hip fractures after strokes occurred on the hemiparetic side. We also found patients with hemiplegia were sicker than patients without hemiplegia according to the ASA rating and more likely to have three or more comorbidities, lower cognitive ability, and weaker walking ability. The aforementioned reasons led to a higher mortality rate in patients with hemiplegia. The patients with hemiplegia also had longer mean days of hospitalization, which is in accordance with previous studies [8, 43] (Table 7).

Table 7
Literature summary

Similar to the study of Clague et al. [4], we observed no association between age and mortality, but another study [38] concluded otherwise (Table 8). This might have been attributable to exclusion of people younger than 65 years and the relatively short followup in our study. We found the type and side of fractures did not affect mortality, although other studies suggested intracapsular [28] or extracapsular fractures [29] increased mortality. Gender, ASA rating, number of comorbidities, prefracture ambulatory status, and cognitive ability showed an effect on mortality in the preliminary analysis, but cognitive ability disappeared in multivariate logistic regression. There are several possible explanations; first, dementia negatively influences health. Second, presumably dementia is entangled with prefracture ambulatory status and/or comorbidities because dementia is related to prefracture ambulatory status and is one of the comorbidities. Male patients were more likely to have more severe medical comorbidities than women and had a greater likelihood of having more severe complications develop after surgery [10]. Obviously, ASA rating and number of comorbidities influence mortality. Prefracture ambulatory status reflects status of physical agility and cardiorespiratory function. Therefore, male gender, three or more comorbidities, Category III or IV ASA rating, and weaker prefracture ambulatory status predicted mortality. Similar results have been reported for patients without hemiplegia who have hip fractures [5, 9, 10, 13, 40].

Table 8
Literature summary of factors affecting mortality

In our preliminary analysis, age, type of fracture, prefracture ambulatory status, and side of fracture did not have an effect on recovery of prefracture ambulatory status. Ishida et al. [17] also reported age did not predict recovery of prefracture ambulatory status after surgery. Other studies [17, 24] reported fracture type did not predict recovery of prefracture ambulatory status. Youm et al. [43] showed the functional recovery of elderly patients with a prior stroke who experience a hip fracture was similar to that of patients without a prior stroke when controlling for prefracture level of function. We found 68.5% of patients with hemiplegia who were surviving at the 1-year followup and were not nonfunctional ambulators before the fracture returned to their prefracture ambulatory status, which is similar to the result reported by Kitamura et al. [22]. In the preliminary analysis, we found gender, ASA rating, number of comorbidities, and cognitive ability influenced recovery of prefracture ambulatory status, however, gender disappeared in the multivariate logistic regression, which is consistent with the results of other studies [17, 24] (Table 9). A possible explanation is that gender is entangled with the ASA rating because men were more likely to have a higher ASA rating for operative risk [10]. Patients with three or more comorbidities [40] or Category III or IV ASA rating generally possess inferior physical capacity, and consequently, their rehabilitation training is limited. Several studies have shown dementia decreases the likelihood of recovery of prefracture ambulatory status [17, 22, 27], a finding our study confirms. Because patients with severe dementia have poor motivation and are unable to follow instructions, it is difficult for them to complete the rehabilitation schedule [22, 27]. Therefore, patients with three or more comorbidities, Category III or IV ASA rating, or moderate to severe dementia were less likely to regain their prefracture ambulatory status.

Table 9
Literature summary of factors affecting recovery of ambulatory status

Our data indicate gender, ASA rating, number of comorbidities, and prefracture ambulatory status are predictors of mortality in elderly patients with poststroke hemiplegia who experience a hip fracture, whereas ASA rating, number of comorbidities, and cognitive ability are factors associated with recovery of prefracture ambulatory status for these patients. These predictors are helpful for us to judge prognosis and curative effect for these patients in clinical practice. In addition, because the mortality rate is higher in patients when compared with patients without hemiplegia, prevention of hip fractures is even more important for patients who have had a stroke. Treatment of osteoporosis and avoiding falls are essential for patients with poststroke hemiplegia.

Acknowledgments

We thank Sun Fei and Zhu Yan (statistical experts) for invaluable statistical advice; Tan Jing, MD, and Alexi for helpful comments on the manuscripts; Dr Nie Qingbing for collecting documents; and Editor-in-Chief, Dick Brand, and editorial assistant, Ryan Krausmann, for invaluable remarks and instructions.

Footnotes

Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.

Each author certifies that his or her institution has approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.

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