Hip fracture is the most common major injury in the elderly and an important cause of mortality and morbidity. The thirty-day mortality is 10%, and 20% to 30% of patients will die within one year after surgery1-3. For the majority of patients, optimum treatment requires surgical management of the hip fracture, and several studies have demonstrated that a delay in surgery increases morbidity and mortality in these patients4-7. Therefore, it is generally recommended that patients with a hip fracture undergo surgery within twenty-four hours after admission8.
Within many health-care systems, the demand for urgent surgery often exceeds the available resources. This leads to a delay in the surgical treatment of patients with a hip fracture for nonmedical reasons. The aims of this study were to compare the effects of delays in the operation for medical and nonmedical reasons on the mortality and morbidity following hip fracture and, if possible, to identify an optimal time for surgery in these often frail patients.
Materials and Methods
All patients with a hip fracture who are admitted to our university hospital are entered into a prospective database. This hospital is the sole provider of orthopaedic trauma care in a city with a population of 650,000. All adult patients with a fracture of the femoral neck are included in the database. Isolated femoral head (Pipkin-type) fractures and acetabular fractures are excluded. An independent audit staff collects data before and after surgery with use of a detailed data form based on the “Standardised Audit of Hip Fractures in Europe (SAHFE)”9 (see Appendix). Recorded data include age, sex, type of housing, mechanism of injury, activities of daily living, medical comorbidities, timing and type of anesthesia and surgery, postoperative complications, length of hospital stay, and social arrangements on discharge. Preinjury mobility was classified as the ability to walk outside the home (either alone or accompanied), the ability to walk inside the home (either alone or accompanied), or the inability to walk. Cognitive ability was evaluated with use of the minimental test score. The database is linked to the Office for National Statistics10, which allows 100% follow-up for mortality statistics, including those on patients who die following hospital discharge.
At our hospital, the consultant orthopaedic surgeon recommends the type of surgery. The majority of intertrochanteric fractures are treated with a sliding hip screw, and, in general, undisplaced subcapital fractures are managed with screw fixation and displaced subcapital fractures are treated with a hemiarthroplasty. All patients are assessed for fitness for surgery by an anesthetist. Routine preoperative investigations include a full blood-cell count, measurement of blood urea and electrolyte levels, a radiograph of the chest, and electrocardiography. Surgery is delayed when a patient requires treatment for acute medical comorbidities, and the condition of such a patient is optimized, usually in conjunction with general physicians, prior to the operation. In this study, early surgery was defined as surgery on the day of admission or the following day. Surgery performed after this time was considered to be delayed.
Surgery is undertaken in a laminar flow theater under the supervision of the consultant orthopaedic surgeon. All patients receive prophylactic antibiotics and thromboprophylaxis with low-molecular-weight heparin. There was no surveillance for preoperative or postoperative thromboembolism. Patients are mobilized the day following the surgery according to their preinjury mobility status and cognitive state.
At our hospital, one hundred hours are available each week for routine operations for trauma, but the demand for surgery often outweighs the supply. Surgery is scheduled according to clinical priority (with life-threatening injuries treated first, then limb-threatening injuries, etc.) and then according to the amount of time that the patient has waited. A trauma coordinator reviews and prioritizes the schedule on a daily basis. This system remained unchanged during the study period (as did the total number of admissions per year). The trauma coordinator and the consultants (except for the senior author [C.G.M.]) were unaware that an observational study of surgical delay was being carried out.
Chi-square tests and the Fisher exact test (two-sided) were used to determine basic statistical results, and these were followed by Kaplan-Meier survival analysis to determine the association between mortality and surgical delay. Patients were censored at the end of the follow-up period. (Survival probabilities involve the estimation of the time until some event, usually death or failure of some sort. Some of the patients may not experience the event because the study ends before they die or because the investigators lose contact with them partway through the study. Partial information is available for these patients: it is known that the event occurred [or will occur] at some time after the date of the last follow-up. We refer to these patients as “censored observations.”11)
Univariate and multivariate Cox regression analysis was used to evaluate the effect of fitness for surgery on the association between the delay until the surgery and the postoperative mortality. This produced hazard ratios, which are similar to odds ratios and relative risks. The hazard ratio is a multiplication factor that expresses the comparative risk of the event occurring between two groups (e.g., a hazard risk of 2.0 equals twice the risk). All multivariate analyses were adjusted for age and sex. A log-rank test for trend was used when appropriate. A number-needed-to-treat analysis of the survival data was performed to determine how many patients would need to move from one group to another to save one person. The SPSS statistical program (version 12.0.1; SPSS, Chicago, Illinois) and Microsoft Excel 2000 (Redmond, Washington) were used for the statistical analysis and data storage. The statistical analysis was undertaken with the supervision of a statistician.
Over the four-year period from May 8, 1999, to May 7, 2003, 2903 patients were admitted to our hospital with a hip fracture. The mean age was eighty years (range, seventeen to 103 years). Sixty-one percent of the patients were more than eighty years old, and 3% were less than fifty years old. There were 2219 women (76%) and 684 men (24%). Two hundred and forty-three patients were excluded from the study: ninety-seven patients who had sequential hip fractures within the study period had the first fracture excluded; six patients with bilateral, simultaneous hip fracture were excluded to ensure independent data; and 140 patients who did not have surgery at our hospital were excluded. Of the 140 patients who did not have surgery at our hospital, eighty-three patients were managed nonoperatively because they were bedbound and had minimal pain, had severe chronic medical conditions, or chose not to have surgical treatment; thirty-seven patients were admitted to our institution for rehabilitation after surgery at another hospital; and twenty patients were admitted to our institution with an acute medical comorbidity that led to death before surgery could be performed. This left a cohort of 2660 patients who underwent hip fracture surgery at our institution, and they were the subjects of this study. Two hundred and ninety-four of these patients had a delayed presentation because the patient had ignored the symptoms or a fracture had not been recognized initially.
Two thousand, one hundred and forty-eight patients (81%) were judged to be fit for surgery on admission; 982 (46%) of these patients had surgery on the day of admission or the following day (the early surgery group) and 1166 (54%) had the operation delayed because of the unavailability of operating room time (the delayed surgery group). The majority of these patients had surgery within five days after admission. Table I lists the length of the delay until surgery and the thirty-day mortality in this group of patients who were fit for surgery.
Three hundred and eighty-nine patients (15%) were deemed unfit for surgery within twenty-four hours after admission, as determined by the trauma, anesthesiology, and medical teams. The most frequent reason for delaying surgery was an acute medical comorbidity that required treatment prior to the operation (206 patients; Table II). Other reasons for delay included investigation for chronic medical comorbidities and staging of patients in whom a pathological fracture was suspected because of a previous diagnosis of a malignant lesion. All of these patients were included in the analysis.
The remaining 123 patients were excluded from the study as there was a delay in the diagnosis of the fracture, they were admitted with a medical condition to a medical ward and were later diagnosed as having a fracture of the neck of the femur, or they were waiting to have an investigation for a fracture (e.g., magnetic resonance imaging or bone scan).
The most common postoperative complications were chest infection (223 patients, 8.4%), cardiac failure (124 patients, 4.7%), and urinary tract infection (103 patients, 3.9%). A deep wound infection developed in twenty-eight patients (1.1%). There was no significant difference in the rate or type of complications, including decubitus ulcers, between patients who had early surgery and those for whom it was delayed for one to four days. There was also no significant difference in the prevalence of clinically detected deep vein thrombosis and pulmonary embolism among patients who were fit for surgery and had no delay (fifteen [1.5%] of 982), patients who were fit for surgery and had a delay (nineteen [1.6%] of 1166), and those who had a delay for medical reasons (two [1.0%] of 206) (p = 0.75). Similarly, the rehabilitation period following surgery, in both the acute ward and the rehabilitation ward, did not differ significantly among groups. The only difference in the total length of stay was in the preoperative wait for the surgery.
The thirty-day postoperative mortality for all patients was 9% (246 deaths). The cumulative mortality with time is shown in Figure 1, which demonstrates a linear relationship between mortality and time for the first twenty days following surgery. This relationship is described by the equation y = 0.3x. After twenty days, the mortality tails off. The mortality was 19% at ninety days, and it rose to 30% by one year (Fig. 2).
Patients Who Were Fit for Surgery
Eighty-five (8.7%) of the 982 patients who were fit for surgery and had the operation early died within thirty days, and eighty-five (7.3%) of the 1166 patients who were fit for surgery but had a delay before the surgery for logistical reasons died within thirty days. This difference was not significant (chi square = 0.43; p = 0.51). We also found no significant trend in mortality when we compared patients who were fit for surgery and had a delay of one to four days (log-rank test for trend statistic = 1.70; p = 0.19) and those who were fit for surgery and had a delay of more than four days (log-rank test for trend statistic = 0.52; p = 0.47).
A delay in surgery of one to four days had no adverse effect on the ninety-day mortality (hazard ratio = 0.99, 95% confidence interval = 0.8 to 1.2; p = 0.91) (Fig. 3) or the one-year mortality (hazard ratio = 1.1, 95% confidence interval = 0.9 to 1.25; p = 0.47). However, multivariate analysis of patients with a delay of more than four days indicated a significant associated increase in mortality at ninety days (hazard ratio = 2.25, 95% confidence interval = 1.2 to 4.3; p = 0.01) and at one year (hazard ratio = 2.4, 95% confidence interval = 1.45 to 3.99; p = 0.001). It should be noted that this analysis had only 6% power as only twenty-eight patients had this length of delay. Multivariate analysis demonstrated that a delay between the fracture and the presentation of more than one day was not a confounding variable in patients who were fit for surgery on admission (hazard ratio = 0.9, 95% confidence interval = 0.6 to 1.3; p = 0.57). An inhospital delay of more than four days remained significant (hazard ratio = 2.2, 95% confidence interval = 1.2 to 4.2; p = 0.01).
A number-needed-to-treat analysis was undertaken with use of the ninety-day mortality statistics. The analysis indicated that, for there to be one additional survivor, five patients would have to have had surgery within one to four days rather than more than four days after admission (95% confidence interval = 2.7 to 67.0).
Acute Medical Comorbidities
Thirty-six (17%) of the 206 patients with acute medical comorbidities on admission died within thirty days after the surgery. In contrast, the thirty-day mortality of the patients who had been declared fit for surgery on admission was 8% (170 of the 2148 patients died). This difference in mortality rates is highly significant (hazard ratio = 2.3, 95% confidence interval = 1.62 to 3.33; p < 0.001) (Fig. 4). Multivariate analysis confirmed that this increase in mortality persisted at ninety days (hazard ratio = 2.1, 95% confidence interval = 1.6 to 2.7; p < 0.001) and one year (28% compared with 43%; hazard ratio = 1.72, 95% confidence interval = 1.38 to 2.15; p < 0.001). In this group of patients with acute medical comorbidities, there was no significant relationship between the timing of the surgery and the mortality at thirty days (hazard ratio = 0.68, 95% confidence interval = 0.34 to 1.39; p = 0.29), ninety days (hazard ratio = 1.16, 95% confidence interval = 0.72 to 1.86; p = 0.54), or one year (hazard ratio = 1.03, 95% confidence interval = 0.68 to 1.58; p = 0.88). Thus, there is no clear optimal time to operate on these so-called high-risk patients (Fig. 5). Multivariate analysis showed that a delay from the fracture to presentation of more than one day (294 patients) was a borderline confounding variable (hazard ratio = 2.1, 95% confidence interval = 1.01 to 4.2; p = 0.048). This means that a delay before presentation was associated with a significant increase in mortality in patients who were medically unfit for surgery.
Patients who sustain a hip fracture have a significantly higher mortality rate in the year following the fracture compared with age-matched controls without a fracture1. Whether a delay in surgery contributes to this increased mortality remains controversial. Several studies have demonstrated that delaying surgery for more than twenty-four hours increases mortality4-7. Other studies have demonstrated no significant difference in the mortality of patients in whom surgery was delayed by up to three days9. There have even been reports suggesting that operating within twenty-four hours may increase mortality10. The majority of these studies have been based on retrospective reviews of patient records or databases12,13, which often did not include the reasons for the delay in surgery. Most studies involved relatively small numbers of patients, whereas, in the larger studies, the data were often collected from several different centers over a long period of time.
The current study has several advantages over previous reports. The data were collected prospectively by an audit staff; the database was linked to the British Office for National Statistics, which allowed a 100% follow-up for mortality; the study included patients treated at a single center over a relatively short period of time; and data on more than 2500 patients were collected. Therefore, the accuracy and statistical power of the study allowed us to draw some firm conclusions.
We demonstrated that a delay of up to four days before hip fracture surgery in patients who are considered fit for anesthesia and an operation (i.e., those with no acute medical comorbidities) does not affect mortality, morbidity, or the length of the postoperative hospital stay. A small number of patients had a delay of more than four days before the surgery. Those delays occurred during severe peaks of admissions (during winter) or after patients had initially declined surgery but later changed their minds. Our analysis indicated that patients with a delay of more than four days have a significantly increased risk of dying by ninety days (hazard ratio = 2.25) and one year (hazard ratio = 2.4). It should be recognized that only twenty-eight patients had the surgery delayed beyond four days so this aspect of the study has limited statistical power. However, the number-needed-to-treat analysis indicated that only five patients needed to undergo surgery within four days after admission to save one additional life. We believe that patients with a hip fracture must be given priority to avoid this length of delay. Health-care systems vary from country to country, but responsible public health bodies should be aware of this problem and ensure that adequate facilities are available for the timely management of these elderly, often frail, patients. In addition, patients who decline surgery should be informed of the potential risks associated with a delay in surgery of more than four days.
The treatment of patients admitted with a hip fracture and an acute medical comorbidity, such as a chest infection, is a challenge. The current study confirmed that this group has a high risk of mortality within thirty days (17%; hazard ratio = 2.3) and at one year (43%; hazard ratio = 1.72). In general, surgery should proceed when the patient's condition is optimal; however, this can be a difficult decision that needs to be individualized and should involve the anesthetist, general (or specialist) physician, and surgeon. Our study gives no indication of the optimal time for surgery in this group of patients but indicates that a delay from the fracture to the hospital presentation is associated with increased mortality.
The limitations of this study must be recognized. It was an observational study, not a randomized controlled trial, so it lacks the accuracy that could be achieved with a protocoldriven study. There was no a priori protocol for determining which patients were unfit for surgery and anesthesia, a judgment that will always vary between clinicians. However, the striking difference in mortality between the patients deemed to be fit for surgery and those considered to be unfit for surgery indicates that current clinical methods are successful in identifying patients who are at increased risk of death following hip fracture surgery. This important subgroup of patients requires separate analysis in future studies, and any national audit should also include a separate analysis of these patients, who could have an important effect on the observed mortality in individual trauma units.
In conclusion, we performed a large, prospective, observational study of patients treated surgically for a hip fracture, with complete follow-up for mortality statistics. The study indicated that a delay in surgery of up to four days in patients without an acute medical comorbidity does not increase postoperative mortality, morbidity, or duration of the rehabilitation following surgery. We do not advocate such delays, as we believe that they cannot be justified on humanitarian grounds; however, when surgical facilities are unable to cope with demand, a short delay before surgery will not significantly increase morbidity and mortality in this group of patients. A delay of more than four days in patients who are fit for surgery significantly increases mortality and must be avoided.
The Standardised Audit of Hip Fractures in Europe (SAHFE) form is available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation and click on “Supplementary Material”) and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM). ▪
NOTE: The authors thank the following clinicians for allowing their patients to be included in this study: Mr. N. Badhe, Mr. N.D. Downing, Mr. D.M. Hahn, Mr. M. Hatton, Mr. B.J. Holdsworth, Mr. C.J. Howell, Mr. J.B. Hunter, Mr. P.J. James, Mr. A.R. Manktelow, Mr. J.A. Oni, Mr. P.J. Radford, Ms. B.E. Scammell, and Mr. E.P. Szypryt. They also thank Dr. Sarah Armstrong, Statistician (University of Nottingham), and Christopher White, Audit Clerk in Trauma and Orthopaedics, for their assistance with this study.
The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
A commentary is available with the electronic versions of this article, on our web site () and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM).
Investigation performed at the Department of Trauma and Orthopaedics, University Hospital Nottingham, Nottingham, United Kingdom
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