Abstract
Background:
Intramedullary nails provide no clear outcomes benefit in the majority of patients with intertrochanteric hip fracture, yet their use in the United States continues to increase. Non-patient factors that are associated with intramedullary nail use among Medicare patients have not been examined. The goal of this study was to identify the surgeon and hospital characteristics that were associated with the use of intramedullary nails compared with plate-and-screw devices among elderly Medicare patients with intertrochanteric hip fractures.
Methods:
Medicare beneficiaries who were sixty-five years of age or older and underwent inpatient surgery to treat an intertrochanteric femoral fracture with use of an intramedullary nail or a plate-and-screw device were identified from the United States Medicare files for 2000 to 2002. Surgeon and hospital characteristics from the Medicare provider enrollment files were merged with the claims. Generalized linear mixed models with fixed and random effects modeled the association between surgeon and hospital factors and intramedullary nail use (compared with plate and screws), controlling for patient age, sex, and race; subtrochanteric fracture; Charlson comorbidity score; nursing home residence; and Medicaid-administered assistance. The adjusted odds ratios of receiving an intramedullary nail by year, surgeon, and hospital factors are reported.
Results:
There were 192,365 claims for surgery to treat an intertrochanteric hip fracture that met the inclusion criteria and matched with surgeon and hospital information. There were 15,091 surgeons who performed intertrochanteric hip fracture surgeries in Medicare patients in 3480 hospitals between March 1, 2000, and December 31, 2002. The surgeon factors associated with intramedullary nail use include younger surgeon age (less than forty-five years old), an osteopathy degree, and operating at more than one hospital. The hospital factors associated with intramedullary nail use include a higher volume of intertrochanteric hip fracture surgeries, teaching hospital status, and having resident assistance during surgery. Surgeon factors improved the model fit more than hospital factors.
Conclusions:
The use of intramedullary nails was strongly associated with early-career surgeons and surgeon training programs. Our findings suggest that orthopaedic faculty at teaching hospitals and younger surgeons may be selecting orthopaedic implants on the basis of factors other than clinical outcomes evidence. We expect that intramedullary nail use will continue to increase as long as new surgeons are preferentially trained in intramedullary nailing procedures and surgeon reimbursement remains insulated from the treating hospital's burden of their choices for higher cost devices under the Medicare payment system.
Level of Evidence:
Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.
More than 280,000 hip fractures occur annually in the United States, and most affect elderly individuals1. Geriatric hip fractures are associated with high morbidity and mortality2-8. Intertrochanteric hip fractures account for nearly half (47%) of all hip fractures in elderly individuals9-12.
The majority of intertrochanteric hip fractures are treated surgically with one of two types of internal fixation devices: a plate with screws or an intramedullary nail. There are no outcomes benefits for intramedullary nails compared with plate and screws in the treatment of stable intertrochanteric hip fractures13-17, which account for up to 70% of such fractures18-21. Intramedullary nails are preferred by many surgeons for patients with intertrochanteric hip fractures with subtrochanteric extension and isolated subtrochanteric fractures22-24, although definitive outcomes support for the use of intramedullary nail devices in unstable fractures has not been established16,17,24-27.
Since 1992, Medicare has paid surgeons more to use intramedullary nail devices than a plate and screws because of the higher assigned relative value units (RVUs) for intramedullary nailing procedures. In contrast, hospitals are paid under the same diagnosis-related group for both the intramedullary nail and plate-and-screw procedures, although the intramedullary nail devices cost hospitals more than plate-and-screw implants13,28,29. Despite equivalent outcomes and higher implant-related complication rates16,17,25,30,31, intramedullary nail use in the United States has continued to increase and is now the dominant mode of internal fixation in the treatment of patients with an intertrochanteric hip fracture28,32,33. Additionally, substantial geographic variation in intramedullary nail use has been identified among Medicare patients with an intertrochanteric hip fracture, which was not explained by patient-related factors21,28.
Non-patient-related factors that are associated with increased intramedullary nail use among Medicare patients have not been examined. The goal of this study was to identify the surgeon and hospital factors that were associated with intramedullary nail use among Medicare patients with an intertrochanteric hip fracture treated with internal fixation during 2000 to 2002, controlling for patient factors. We hypothesized that experienced orthopaedic surgeons and surgeons in teaching hospitals were most likely to use an intramedullary nail for intertrochanteric hip fracture treatment during 2000 to 2002.
Data Sources and Patient Selection
Medicare claims and enrollment data from March 1, 2000, through December 31, 2002, were used to identify Medicare beneficiaries who were sixty-five years of age or older, were enrolled in Parts A and B, were not enrolled in managed care plans, and underwent inpatient surgery to treat an intertrochanteric hip fracture with use of either an intramedullary nail or a plate-and-screw device. We used 2000 to 2002 as the study period because intramedullary nail devices were in widespread use in the United States and did not undergo design modifications from 1998 through 2002.
Patients were included if there was a specific, five-digit ICD-9 (International Classification of Diseases, Ninth Revision34) diagnosis code for a pertrochanteric femoral fracture (820.2x to 820.3x) on either the hospital or the physician claim for a particular surgical procedure, the corresponding claim in the other provider file had one of four ICD-9 diagnosis codes (820.2x, 820.3x, 820.8, or 820.9), and the patient was treated with either an intramedullary nail or plate-and-screw device by CPT (Current Procedural Terminology35) codes 27245 or 27244, respectively.
Patient data were obtained from the Medicare Provider Analysis and Review hospital claim files, the Medicare Part B (physician) claim files, and the Denominator (enrollment) files. Surgeon and hospital characteristics were determined from the Medicare Physician Identification and Eligibility Registry file and the Medicare Provider of Services facility file, and merged with the claims with use of the unique Medicare provider numbers.
Surgery dates were matched by patient identifier across the hospital and physician claims within a ±7-day time frame36. For patients with more than one intertrochanteric hip fracture during the study period, only the first surgical claim was retained. Since our interest was in index, low-energy hip fractures in elderly patients, we excluded patients whose hospital claim indicated surgery for complications or revisions of previous hip surgery, metastatic or associated cancers, infection, bilateral fracture, or high-energy trauma. Additional case selection details have been previously reported21.
The study was reviewed by the University of Minnesota institutional review board and was determined to be exempt.
Variables
The dichotomous outcome of interest was the type of implant used, either an intramedullary nail or plate and screws. The procedure code on the surgeon's claim enabled us to determine the specific internal fixation device used in each patient. The unit of analysis was the patient. Surgeon and hospital characteristics were used as predictors while controlling for patient factors. A year indicator was also included to account for changes in intramedullary nail use over time.
Each surgeon's volume of intertrochanteric hip fracture surgeries in Medicare patients was calculated as the total number of internal fixation procedures performed per surgeon provider number between March 1, 2000, and December 31, 2002. Surgeon volume was categorized into quartiles to facilitate comparison. As an estimate of surgical experience, each surgeon's age in years was calculated from his or her date of birth in the Medicare Physician Identification and Eligibility Registry file to December 31, 2001, and was then divided into five-year age categories. Orthopaedic board certification status (yes or no) and professional degree (MD or DO [doctor of osteopathy]) were determined from the Medicare Physician Identification and Eligibility Registry file, while practice structure (group or other) was determined from both the Medicare Physician Identification and Eligibility Registry file and the surgeons’ claims. The number of hospitals where each surgeon surgically treated patients with an intertrochanteric hip fracture (number of case hospitals) was determined from the number of unique hospital identifiers per surgeon identifier (1, 2, 3, and =4) in the claims.
Each hospital's volume of intertrochanteric hip fracture surgeries in Medicare patients was calculated as the total number of Medicare patients who had internal fixation for an intertrochanteric hip fracture per hospital identifier during the thirty-four-month study period. Each hospital's case volume was then grouped into a four-level categorical variable by volume quartiles. The type of hospital ownership (for profit, nonprofit, or government) and teaching status (nonteaching, teaching without any resident assistance in cases, or teaching with resident assistance in one case or more) were determined from the Provider of Services file, and medical resident case involvement under the direction of a teaching physician was determined by the presence of a —GC modifier on the procedure code from the surgeon's Part B claim35,37.
Our models contained patient factors that potentially influence device choice, including age (sixty-five to seventy-four years, seventy-five to eighty-four years, and eighty-five years or more), sex, race (white, black, or other), residence in a nursing home before the fracture (yes or no), subtrochanteric fracture, and state Medicaid-administered assistance. We considered patients to have resided in a nursing home at the time of fracture if we identified at least one Medicare Part B provider claim that took place in a nursing home within two months preceding the date of hip surgery using the Place of Service code from any provider's Part B claim38. To control for differences in socioeconomic status, patients who received state Medicaid-administered assistance during their hospital stay were identified from monthly enrollment indicators in the Denominator file. We then created a four-level categorical variable by cross-classifying preadmission residence (nursing home or other) with state Medicaid-administered assistance status (yes or no) to avoid potential bias from nursing home patients in the regression coefficient for state Medicaid-administered assistance. The adapted Charlson comorbidity scores (0, 1, 2, or =3)39,40 were excluded from our final models because of the lack of significance in predicting device choice in all preliminary models, which was consistent with prior work on patient factors that used device choice as the outcome21.
Separate models were estimated by calendar year and then pooled for the final analyses because of the consistency of our findings over time. We excluded cases with surgical dates prior to March 1, 2000, to allow for the two-month nursing facility claim look-back, which resulted in a thirty-four-month analytic file.
Statistical Analyses
We used generalized linear mixed models with fixed and random effects to model the association between surgeon and hospital factors and the outcome of device choice (intramedullary nail or plate and screws), while controlling for patient factors. Random effects models are typically used to study variation, rather than simply control for it. These models can account for the correlated nature of the data and the imperfect nesting of surgeons within hospitals41,42. Patients in this study were perfectly nested within surgeons, but surgeons often operated at several hospitals, with just over half of the surgeons operating at only one hospital during the study period. Likelihood ratio tests were used to compare nested models41. Non-nested models were compared with use of information criteria, which penalizes the log likelihood for the number of model parameters (Akaike information criterion; AIC) or subjects (Bayesian information criterion; BIC), with smaller values indicating better fit of the model to the data41.
We considered three types of models: fixed (means) without random intercepts, random hospital intercepts, and random surgeon intercepts. We examined four groups of predictors, each with and without random surgeon or hospital intercepts, for a total of twelve models, including an intercept-only model; patient factors with year; patient and surgeon factors with year; and patient, surgeon, and hospital factors with year, for which Akaike and Bayesian information criteria model fit estimates are reported. Analyses were conducted with use of the SAS statistical program, NLMIXED procedure (version 9.1 for Windows; SAS Institute, Cary, North Carolina). Coefficient estimates, standard errors, odds ratios, and 95% confidence intervals for the odds ratios are reported for the regression results. Descriptive statistics are reported as the percentage, mean, or median.
Source of Funding
The Centers for Medicare and Medicaid Services provided the data for this study but did not play a role in the investigation.
Sample Description
Between March 1, 2000, and December 31, 2002, 192,365 Medicare claims for intertrochanteric hip fracture surgeries met our inclusion criteria and matched with complete surgeon and hospital information (98.2% matched). Intertrochanteric hip fracture surgeries with internal fixation were performed by 15,091 surgeons in 3480 United States hospitals for fee-for-service Medicare beneficiaries during that time period. The proportion of patients with an intertrochanteric hip fracture who received an intramedullary nail compared with a plate and screws increased from 8.1% of the patients in 2000 to 17.1% in 2002.
The provider characteristics are described in Table I. The median age among surgeons was forty-six years. Over the thirty-four-month study period, the median surgeon volume of intertrochanteric hip fractures was ten cases (average, 3.4 cases per year); 7.8% of surgeons operated on only one patient during the study. Surgeons with an MD degree composed 95.4% of the providers, and surgeons were almost exclusively self-identified as orthopaedic surgeons (98.4%). Nearly two-thirds (64.9%) of surgeons were orthopaedic board certified; 64.2% practiced in a group practice. Just over half of surgeons (55%) operated at only one hospital, while 14.2% of surgeons operated at three or more hospitals during the study.
The median number of Medicare patients treated for an intertrochanteric hip fracture per hospital was forty-one over thirty-four months, or approximately fourteen patients per year (Table I). Eighty hospitals (2.3%) treated only one patient who had a hip fracture with internal fixation during the study period. Two-thirds (66.9%) of the case hospitals were nonprofit facilities. The majority of hospitals (69.1%) were not teaching facilities. Only 150 hospitals (4.3%) were teaching hospitals that had resident involvement in surgical cases, and an additional 26.6% of the hospitals were identified as teaching hospitals without resident assistance during hip fracture surgeries.
The patients were, on the average, eighty-four years old (Table II); 77.2% were female and 94.6% were white. Subtrochanteric fractures were identified in 10.6% of the patients. One-fifth (20.1%) of the patients with a hip fracture were admitted from a nursing home. The majority (80.8%) of patients did not receive state Medicaid-administered assistance.
Surgeon Random Intercepts Model
The results from the best-fitting model, the surgeon random intercepts model with the full set of predictors, are shown in Table III. This regression model shows the average effect of each predictor across surgeons, but additionally it allows each surgeon to have their own intercept, or baseline probability of intramedullary nail use. The odds of a patient with an intertrochanteric hip fracture receiving an intramedullary nail device compared with a plate and screws in 2001 were 1.77 times higher than in 2000, and nearly five times higher in 2002 compared with 2000 (odds ratio, 4.68; 95% confidence interval, 4.40 to 4.97).
There was an inverse relationship between the age of the surgeon and intramedullary nail use. After controlling for patient and other provider factors, surgeons under the age of forty-five years had higher odds of intramedullary nail use compared with surgeons in the median age group (forty-five to forty-nine years old), with the highest comparative odds of intramedullary nail use among the youngest group of surgeons (less than thirty-five years old) (odds ratio, 5.13; 95% confidence interval, 3.87 to 6.81). Surgeons who were fifty years or older had significantly lower odds of selecting an intramedullary nail than did surgeons who were forty-five to forty-nine years old; however, the standard errors for surgeons who were fifty years or older were slightly larger than for those who were less than forty-five years old, indicating larger variability in device choice among the older surgeons.
Surgeons’ volume of patients with an intertrochanteric hip fracture was not significantly associated with device selection. The odds of receiving an intramedullary nail device among patients of surgeons who performed four or fewer operations over the thirty-four months were not significantly different from the odds of receiving an intramedullary nail among patients of the highest-volume surgeons (eighteen patients or more). Although not significant, there was a U-shaped trend in the odds ratios of intramedullary nail use by surgeon volume categories, with lower values among mid-volume surgeons relative to the highest and lowest-volume providers.
The odds ratios of intramedullary nail use increased as the number of hospitals where a surgeon performed such procedures increased. Patients of surgeons who performed hip fracture surgeries at four or more hospitals had more than double the odds of receiving an intramedullary nail device than did patients of surgeons who operated at only one hospital, controlling for other factors (odds ratio, 2.4; 95% confidence interval, 1.76 to 3.38).
After controlling for surgeon age and other patient and provider factors, patients treated by doctors of osteopathy had twice the odds of receiving an intramedullary nail device than did patients of medical doctors.
Orthopaedic board certification and practice structure were not significantly associated with intramedullary nail use. A provider specialty indicator variable (orthopaedic or other) was omitted from the final models because it was not significantly related to device choice in all preliminary models among this almost exclusively orthopaedic provider group.
Hospitals’ volume of Medicare patients with an intertrochanteric hip fracture was positively associated with intramedullary nail use (Table III). Compared with the highest volume hospitals (seventy-nine operations or more overall and corresponding to twenty-eight operations or more per year), patients surgically treated in hospitals that performed less than the median volume of forty-one operations during the study had 16% to 17% lower odds of receiving an intramedullary nail, controlling for other factors. Hospitals that performed just above the median number of operations (third volume quartile) were equally as likely to use intramedullary nails as hospitals in the highest volume quartile for patients with a hip fracture.
Patients treated at teaching hospitals that did not have resident assistance during surgeries had 12% higher odds of receiving an intramedullary nail for the fracture than patients treated at nonteaching facilities. Moreover, patients who had the surgery performed at a teaching hospital with resident assistance during surgery had 58% higher odds of receiving an intramedullary nail device than patients treated at nonteaching hospitals, controlling for patient and other provider factors. Intramedullary nail use did not significantly differ by the type of hospital ownership.
Patient Covariates
Patients with a subtrochanteric fracture compared with other pertrochanteric fractures had substantially higher odds of receiving an intramedullary nail (odds ratio, 17.51; 95% confidence interval, 16.47 to 18.61; see Appendix), although only one-third of patients with a subtrochanteric fracture received an intramedullary nail during this period. Consistent with previous work21, the influence of other patient factors on intramedullary nail use was generally modest and tended to contradict the device use expectations based on claim factors that correlate with clinical factors, such as low bone density43,44.
Model Comparisons
Our findings are highly consistent across all three models (Table III and Appendix). Regardless of how we modeled the provider-device association, we arrived at the same conclusions regarding the influence of various provider predictors on intramedullary nail use. Although the magnitude of each factor's influence differed across models, the direction of the influence of each predictor on intramedullary nail use essentially did not change, regardless of the model used. The odds ratios for the influence of the surgeon's age, his or her professional degree, the number of hospitals where the surgeon operated, the hospital's teaching status, and the hospital's case volume were particularly stable across all models. The effect of the surgeon's case volume was similar across the three models, but it was not a significant predictor of device choice in the model with surgeon random intercepts, suggesting a great deal of variation in intramedullary nail use among providers within the surgeon volume strata. The odds ratios of intramedullary nail use, particularly among young surgeons (less than forty years old), showed dramatic increases with use of the surgeon random intercepts model.
Model Fit
The models with either surgeon or hospital random intercepts had significantly better fit than the models without random effects (p < 0.0001 for likelihood ratio tests; results not shown). The surgeon-specific random intercepts models better fit the data (lower information criteria) than the hospital-specific random intercepts models did. The best-fitting model contained all patient, surgeon, and hospital predictors with surgeon random intercepts (see Appendix). However, after inclusion of the surgeon-specific intercepts, the addition of the hospital predictor variables only minimally improved the model fit.
We found a strong association between surgeon factors, teaching hospital status (with and without resident involvement in surgery), and hospital volume and intramedullary nail use in the treatment of intertrochanteric hip fracture in Medicare patients during 2000 to 2002. Surgeon factors accounted for more of the variation in intramedullary nail use than the hospital factors we examined.
Younger surgeons were the primary adopters of the intramedullary nailing procedures, likely reflecting higher intramedullary nail use in surgeries performed at the teaching hospitals that trained them. Given the seventeen-year duration of higher RVUs for intramedullary nailing procedures largely because of the work RVU component, we expected the odds of intramedullary nail use to be higher among mid-career, board-certified surgeons in group practices45,46 who had attained some degree of experience and surgical proficiency that would enable them to master a new procedure that Medicare estimated would require more planning and technical skills, greater judgment, and a longer time to perform than plate-and-screw procedures for intertrochanteric hip fracture. Experienced teaching surgeons who mentored and educated residents first had to adopt intramedullary nailing procedures in order to train young surgeons in the technique. By the time of this study, however, we found the highest intramedullary nail use among the youngest surgeons, presumably with the least experience, implying that our study took place somewhere during mid-diffusion of intramedullary nail technology into hip fracture treatment. Our findings suggest that younger surgeons continue to perform the procedures that they become familiar with in training, while older surgeons, who may be more comfortable or proficient with plate-and-screw procedures, were less likely to change to the newer intramedullary nail devices during 2000 to 2002.
Assuming that both surgical skill and judgment improve with experience and given the intramedullary nail adoption pattern found among the youngest and least experienced surgeons, these findings challenge Medicare's estimate through 2008 that intramedullary nailing procedures require superior surgical skills and surgeon judgment. Our finding of high intramedullary nail use among young surgeons is consistent with recent patterns of intramedullary nail use noted in the American Board of Orthopaedic Surgery data28.
The precise mechanisms that account for our finding of higher intramedullary nail use among osteopathic surgeons compared with surgeons with a medical degree in all models suggest that there are additional, unmeasured factors that differentially affect decisions by osteopathic surgeons in their implant choices for patients with an intertrochanteric hip fracture.
After controlling for patient and other provider factors, we found higher odds ratios of intramedullary nail use among surgeons who operated at more than one hospital, particularly among surgeons who operated at four or more hospitals. Compared with surgeons who operated at one hospital, those who operated at four or more hospitals were younger (a median age of forty-two years compared with forty-seven years), had a higher average case volume (seventeen compared with seven cases), and more often held a degree in osteopathy compared with a medical degree (10.2% compared with 3.7%), but the difference persisted even when surgeon age and other factors were controlled in our models. Lower use of intramedullary nails among surgeons who operated at one hospital may reflect their greater cognizance of the facility costs incurred by their device choices within their host hospitals, rather than their slightly higher median age.
One-third of the hospitals in this study were staffed by at least one surgeon who operated at four or more hospitals, and these hospitals tended to be moderate-to-high volume, nongovernment facilities. A greater proportion of the hospitals used by surgeons who operated at four or more hospitals were teaching facilities, and these teaching hospitals had the same proportion of cases with surgical resident involvement compared with hospitals that did not have cases by surgeons who operated at four or more hospitals. These findings, combined with higher intramedullary nail use in high-volume hospitals, suggest that factors other than orthopaedic surgeon coverage or resident availability, such as faster procedure times28,47, may be a factor in intramedullary nail use that allows more rapid operating-room turnover in high-volume hospitals, thereby at least partially offsetting the higher cost of intramedullary nail devices to these hospitals24,28,29.
The modestly higher use of intramedullary nails among teaching hospitals compared with nonteaching hospitals reflects their earlier adoption of new technology in general46,48. There are several possible explanations for earlier adoption of technology among teaching hospitals. Academic surgeons at teaching hospitals may feel responsible for educating surgeon trainees in state-of-the-art techniques. Academic surgeons may also be more likely to work closely with manufacturers to design and test new devices49,50. The orthopaedic device industry may provide surgeons in teaching hospitals with intensive marketing and operating-room attention for select devices in the hopes of training a new cohort of surgeons in these procedures. Although teaching hospitals may treat patients with more severe case-mix profiles than nonteaching facilities do, the substantially higher odds of receiving an intramedullary nail device in hospitals with resident involvement in cases, compared with those without resident involvement, suggest that there are differences in patient selection for operations in which resident involvement is allowed or other intramedullary nail-related incentives that uniquely affect resident-supervising surgeons that we were not able to account for in this analysis. Ironically, both younger surgeons and teaching surgeons who are expected to have greater understanding of evidence-based medicine principles than older and nonteaching surgeons51 were most likely to select intramedullary nail implants to treat intertrochanteric femoral fractures in this study.
Two important strengths of this claims-based study are the large number of patients with a hip fracture for whom we were able to evaluate device-related provider patterns and the inclusion of multiple patient and provider variables to predict the device choice outcome.
We acknowledge several important limitations of our study. Our analysis incorporated only one random effect at a time, which limited our ability to analyze provider patterns with higher degrees of nesting. However, given the stability of the direction of the findings across the models examined, we do not expect that alternative models would change the overall findings.
The patients in this study were in fee-for-service Medicare only; full provider volumes, especially in areas of high enrollment in managed care, are not reflected. However, given the insignificant effect of surgeon volume on intramedullary nail use, potential underclassification of surgeon volume in several states that had high enrollment in Medicare managed care in 2000 to 2002 would most likely not change our overall surgeon volume findings. We would expect any misclassification of hospital volume to enhance or not substantially change our hospital volume findings, given the positive effect of volume on intramedullary nail use. We would not expect subtrochanteric fracture rates or fracture patterns that may impact device selection to differ by the type of insurance.
We were unable to account for other factors that may influence the surgeon's device choice for Medicare patients with an intertrochanteric hip fracture, including specific fracture patterns, procedure speed and ease, marketing and related device industry influences, clinical patient features, and the surgeon's opinion about which fracture patterns are unstable, none of which are available in claims-based studies. In the presence of preferential training in intramedullary nailing procedures, we do not expect that inclusion of data on fracture patterns would change our findings. We do not expect systematic variation in unstable fractures that would favor newly trained surgeons or teaching and high-volume hospitals, particularly for what is essentially a nonelective surgical condition. Additionally, there is no consensus among surgeons as to which intertrochanteric fracture patterns constitute unstable fractures, particularly within the AO/OTA 31-A2 subtypes52. Thus, the decision to label a fracture as unstable relaxes the clinical criteria necessary to justify the selection of an intramedullary nail device.
Practice structure and orthopaedic board-certification status were not significantly associated with intramedullary nail use when other surgeon factors were included in the models. Board-certification status is likely underidentified in the Medicare provider enrollment file, since it is not required enrollment information for Medicare providers53,54, may reflect initial provider enrollment prior to board examinations, and may only be updated for practice site changes. Neither variable affects Medicare payments to surgeons, and the validity of the board certification and group practice identifiers in the Medicare Physician Identification and Eligibility Registry file specifically among orthopaedic surgeons have not been examined54.
Finally, although this study used Medicare patient information derived from claims for case selection, excellent concordance has been shown between the Medicare physician and hospital claim files in the identification of hip fracture diagnoses and type of implant used36. However, this device validation was reported only for femoral neck fractures for which only one CPT code is used to report two distinct procedures36. In contrast to femoral neck fractures, internal fixation procedures for intertrochanteric hip fractures are CPT code-specific to both fracture site and device (27244 and 27245) in the physician claim files and both diagnosis and ICD-9-CM procedure code in the hospital files, which enhances the validity of our case determination for this exclusively claims-based study36,55.
In conclusion, the use of intramedullary nail devices was strongly associated with early-career surgeons and hospitals with surgeon training programs. Despite the emphasis on evidence-based medicine, our findings suggest that orthopaedic faculty at teaching institutions, surgeons at high-volume hospitals, and younger surgeons are tending to select orthopaedic implants that are more expensive but not more effective. We expect that intramedullary nail use will continue to increase as long as new surgeons are preferentially trained in intramedullary nailing procedures and surgeon reimbursement remains insulated from the treating hospital's burden of their choice of higher cost devices under Medicare's diagnosis-related group payment system. We recommend further analysis to determine how these device-related provider patterns affect outcomes for Medicare patients after surgery for intertrochanteric hip fracture.
Tables showing the influence of patient factors on intramedullary nail use, the influence of provider factors using alternate models, and the relative improvement of model fit from successive models are available with the electronic version of this article on our web site at jbjs.org (go to the article citation and click on "Supporting Data").
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