Operative Treatment of Acetabular Fractures in the Medicare Population

Transcription

1 Operative Treatment of Acetabular s in the Medicare Population Peter J. Hayes, BA; Colin M. Carroll, MD; Craig S. Roberts, MD, MBA; David Seligson, MD; Edmund Lau, MS; Steven Kurtz, PhD; Kevin Ong, PhD; Arthur L. Malkani, MD abstract Full article available online at Healio.com/Orthopedics. Search: The purpose of this study was to determine the incidence of and evaluate the risk for complications and mortality following open treatment of acetabular fractures in the Medicare population. Patients treated with open reduction and internal fixation (ORIF) for acetabular fractures were identified using current procedural terminology codes in a 5% national sample of Medicare records. s within 90 days and within 1 year were evaluated based on the presence of ICD-9-CM diagnosis codes and Current Procedural Terminology reoperation codes. A total of 1286 fractures were treated closed and 359 were treated with ORIF. Multivariate Cox regression was performed to compare complication rates and risk factors. The incidence of acetabular fractures in the Medicare population has increased by 29% since s in the ORIF group included cardiac complications, deep venous thrombosis, infection, pulmonary embolism, refixation, and conversion to total hip arthroplasty. Risk factors for complications with ORIF included advanced age and comorbidities. Mortality in the ORIF group was 14.4% at 1 year. The incidence of reoperation with conversion to total hip arthroplasty or revision fixation following ORIF is 10% and 15%, respectively. Further investigation is required to improve outcomes and decrease complications in this group of patients, especially cardiac, deep vein thrombosis, and infection. The authors are from the Department of Orthopaedic Surgery (PJH, CMC, CSR, DS, ALM), University of Louisville, Louisville, Kentucky; and Exponent, Inc, Menlo Park, California (EL) and Philadelphia, Pennsylvania (SK, KO). This study was funded by a grant from Synthes. Mr Hayes and Dr Carroll have no relevant financial relationships to disclose. Dr Roberts receives support from Skeletal Trauma and receives institutional support for research from Synthes. Dr Seligson receives consultation support from Stryker. Dr Lau receives grant support and manuscript review support from Synthes, Stryker, and Medtronics. Dr Kurtz receives grant support from Synthes, Stryker, Zimmer, Biomet, Formae, JMM, Medtronic, and Stellcast and receives manuscript review support from Synthes. Dr Ong receives grant support from Synthes and manuscript review and preparation support from Stryker. Dr Malkani receives grant support from Synthes and Stryker and receives consultation, speaking, patent, royalty, educational presentation, manuscript preparation, and meeting support from Stryker. Presented at the American Academy of Orthopaedic Surgeons Annual Meeting; February 15-19, 2011; San Diego, CA. Correspondence should be addressed to: Arthur L. Malkani, MD, Department of Orthopaedic Surgery, University of Louisville, 550 S Jackson St, 1st Floor, ACB, Louisville, KY (art.malkani@louisville.edu). doi: / AUGUST 2013 Volume 36 Number 8 e1065

2 Acetabular fractures in elderly patients can be a challenging problem due to their underlying comorbidities and osteoporotic bone. Culemann et al 1 stated that the most typical acetabular fracture pattern in elderly patients was an anterior column fracture combined with a posterior hemitransverse. Treatment options for acetabular fractures in elderly patients include nonoperative treatment, percutaneous fixation, open reduction and internal fixation (ORIF), and arthroplasty. 2-8 Treatment options are based on several factors, including fracture pattern, quality of the host bone, extent of comminution, age of the patient, and associated comorbidities, 2-8 as well as the surgeon s level of expertise at the institution where the patient is being treated. The purpose of this study was to identify the incidence, complications, and mortality of operative treatment of acetabular fractures in the Medicare population at 90-day and 1-year follow-up and identify any associated risk factors. Materials and Methods The administrative claims data for a 5% nationwide sample of Medicare beneficiaries between 1998 and 2007 was used to identify patients with acetabular fractures undergoing ORIF or closed reduction. The Medicare database has been used for longitudinal studies of revision risk and complication risk following total joint arthroplasty Using the physician s component of the claims data (Part B file), patients who underwent ORIF to treat a wall fracture, a fracture, or a fracture were identified using CPT-4 codes to 27228, respectively. Patients who underwent closed reduction were identified using CPT codes or Patients younger than 65 years, those enrolled in a managed-care program, or those not enrolled for a full year prior to the fracture were excluded from the study. Patients younger than 65 years who enroll in Medicare qualify for benefits because of disability or end-stage renal disease. Claims for managed-care enrollees are not submitted to the Centers for Medicare and Medicaid Services for payment and, therefore, claims from these beneficiaries may not be complete. The full year of enrollment was required to allow the evaluation of comorbidities for all patients in the 12 months prior to the fracture. Subsequent to their surgical treatment, patients were followed for up to 1 year. Patients who were diagnosed with subsequent complications, except mortality, were identified from both the hospital (Part A) and physician (Part B) files using relevant diagnosis and procedure codes. s included deep venous thrombosis (DVT), infection, mechanical complications, malunion/nonunion, pulmonary embolism (PE), cardiac complications, conversion to hip replacement (or revision hip replacement for patients with primary total hip arthroplasty [THA]), and reoperation with subsequent ORIF. The mortality rate for each treatment type was also determined using the Medicare denominator file. Each beneficiary s enrollment status and date of death were identified in the annual Medicare denominator files to determine mortality. The cumulative incidence of these complications were computed for up to 90 days postoperatively, except for malunion/nonunion, conversion to hip replacement, reoperation with subsequent ORIF, and mortality, which were computed for up to 1 year postoperatively. To evaluate the relative risk of complications and mortality between the various treatment groups, multivariate Cox regression analysis was used, adjusting for age, sex, race, comorbidity (Charlson comorbidity index), year of the procedure, period ( or ), socioeconomic status, and type of acetabular fracture (for the ORIF group). The health status of each patient was determined using the Charlson comorbidity index score, which was based on each patient s diagnoses in the 12 months prior to treatment. Patients were categorized based on their overall comorbidity score: 0 (none), 1 to 2 (low), 3 to 4 (moderate), and 5 or more (high). Medicare buy-in status for each patient was used as a proxy for their socioeconomic status because it identified patients whose Medicare premiums and deductibles were subsidized by the state due to their financial status. Results A total of 1645 patients with acetabular fractures who underwent ORIF or closed reduction were identified from the 5% sample of the Medicare dataset. Using the 5% sample size, the number of patients increased from 150 in 1998 to 194 in 2007, corresponding with a 29% increase in trend over the past decade. Of the 1645 patients, 359 were treated with ORIF for acetabular wall fractures (n599), fractures (n5111), and fractures (n5149). Of patients treated with ORIF for fractures, 61.7% were men. By contrast, of patients treated with ORIF for wall fractures and fractures, 48.5% and 45.1%, respectively, were men. Furthermore, patients undergoing ORIF for fractures tended to be older, with approximately 30% of patients aged 80 years and older (Table 1). The short-term outcomes for patients undergoing ORIF did not generally differ by fracture type. Compared with patients who underwent ORIF for acetabular wall fractures, those with fractures had a 4.5-fold higher adjusted risk of infection at 90 days (P5.031) (Table 2) but a lower adjusted risk of cardiac complications (284%) at 90 days. However, no other differences in complications at 90 days or 1 year (Table 3) existed among patients undergoing ORIF for wall,, or fractures. Of the complications examined in this study, DVT and mechanical complications were the most frequently reported 90-day complications in the ORIF group (Table 2). The cumulative incidence of DVT at 90 days averaged 16.1%, while the cumulative incidence of mechanical e1066 ORTHOPEDICS Healio.com/Orthopedics

3 Operative Treatment of Acetabular s in the Medicare Population Hayes et al Table 1 Cumulative Rate and Relative Risk at 90-day Follow-up for ORIF Wall Cumulative Incidence, % Adjusted Risk Ratio [95% CI] (P) vs Cardiac a [0.03, 0.72] (.017) 0.50 [0.21, 1.18] (.11) 3.21 [0.69, 14.9] (.14) DVT [0.59, 2.52] (.60) 1.31 [0.66, 2.58] (.44) 1.08 [0.59, 1.96] (.81) Infection a [1.17, 26.0] (.031) 2.58 [0.52, 12.7] (.24) 0.47 [0.17, 1.26] (.13) Mechanical [0.44, 1.67] (.65) 0.77 [0.40, 1.47] (.42) 0.90 [0.47, 1.70] (.74) PE [0.34, 9.59] (.49) 3.13 [0.68, 14.4] (.14) 1.74 [0.58, 5.24] (.32) Abbreviations: CI, confidence interval; DVT, deep venous thrombosis; ORIF, open reduction and internal fixation; PE, pulmonary embolism. a P,.05. Table 2 Cumulative Rate and Relative Risk at 1-year Follow-up for ORIF Wall Cumulative Incidence, % Adjusted Risk Ratio [95% CI] (P) vs Death [0.61, 2.65] (.52) 0.85 [0.41, 1.78] (.67) 0.67 [0.34, 1.31] (.25) Malunion/ nonunion Conversion to THA Reoperation with ORIF [0.40, 5.28] (.57) 1.63 [0.50, 5.34] (.42) 1.12 [0.40, 3.18] (.83) [0.44, 2.56] (.90) 1.05 [0.46, 2.37] (.91) 0.99 [0.44, 2.22] (.98) [0.43, 1.97] (.82) 1.07 [0.55, 2.09] (.85) 1.17 [0.60, 2.29] (.65) Abbreviations: CI, confidence interval; ORIF, open reduction and internal fixation; THA, total hip arthroplasty. complications at 90 days averaged 16.5%. Mechanical complications included loss of fixation and broken hardware. Mortality and re-operation with ORIF were the most frequently reported complications at 1 year (Table 3), with an average mortality rate of 14.4% and an average reoperation rate of 14.9%. Patients undergoing closed reduction had a lower risk of complications at 90 days (Table 4) and 1 year (Table 5). Discussion The purpose of this study was to evaluate the incidence of and risk factors leading to complications and mortality following ORIF of acetabular fractures in the Medicare population between 1998 and The use of the 5% national sample of Medicare records for longitudinal studies and the complication risks has been established in the total joint literature and only recently has been used in the orthopedic trauma literature The results of this study come from a 5% national sample of this Medicare database using ICD-9 codes along with Current Procedural Terminology codes. An overall 29% increase occurred in the incidence of acetabular fractures in the Medicare population during the study period. The authors surmise that the increase in the incidence of acetabular fractures in elderly patients is primarily due to the fact that patients are living longer and trying to maintain their functional activities. In this group of elderly patients, acetabular fractures can result from high-energy trauma in addition to low-energy trauma due to compromised or osteoporotic bone. Treatment options for acetabular fractures in elderly patients include ORIF, closed reduction, and, on rare occasions, immediate arthroplasty. 7,12-18 Carroll et al 3 developed algorithms for the treatment of acetabular fractures in elderly patients that take into consideration these multiple factors, including comorbidities. Elderly patients who are active and ambulatory are most likely to be treated with ORIF, whereas nonambulatory elderly patients are more likely to be treated with closed reduction. The 90-day complication risk with respect to cardiac complications, DVT, in- AUGUST 2013 Volume 36 Number 8 e1067

4 Table 3 Patient Demographics Table 4 Comparison of Rates at 90 Days Demographic Sex fection, mechanical complications, and PE were greater in the ORIF group than in the closed reduction group, which was statistically significant in each group (Table 4). The complication risk at 1-year followup with respect to nonunion, malunion/ nonunion, conversion to THA and reoperation, and redo external fixation was also greater in the ORIF group compared with the closed reduction group. The risk of reoperation and redo internal fixation in the ORIF group was 15% at 1 year. Loss of fixation or fracture migration is common in this patient population, given the osteoporotic bone. The incidence of conversion to THA following failed treatment was 10.3% after ORIF. The incidence of conversion to THA in this series seems lower % Closed Reduction (n51286) ORIF (n5359) Male Female Age, y > Race White Black Other Charlson index score > Abbreviation: ORIF, open reduction and internal fixation. than in the literature. Carroll et al 3 reported an incidence of approximately 31% of delayed THA due to failed operative intervention of acetabular fractures in elderly patients. Their follow-up was more than 2 years. 3 The current authors believe that if their series had extended its follow-up to approximately 2 years, their results may be similar. Follow-up in this longitudinal series stopped at 1 year after to the index procedure and, therefore, did not capture patients who may have progressed to arthrosis after 12 months. The overall mechanical failure rate in the ORIF group leading to % Closed Reduction ORIF Adjusted Risk Ratio [95% CI] a Cardiac [0.35, 0.96].032 DVT [0.30, 0.60],.001 Infection [0.09, 0.41],.001 Mechanical [0.06, 0.16],.001 PE [0.21, 0.77].006 Abbreviations: CI, confidence interval; DVT, deep venous thrombosis; ORIF, open reduction and internal fixation; PE, pulmonary embolism. a ORIF group as reference group. Table 5 Comparison of Rates at 1 Year % Closed Reduction ORIF Adjusted Risk Ratio [95% CI] a Death [0.95,1.77].10 Malunion/ nonunion Conversion to THA Reoperation with ORIF [0.08, 0.38], [0.13, 0.38], [0.06, 0.18],.001 Abbreviations: CI, confidence interval; ORIF, open reduction and internal fixaton; THA, total hip arthroplasty. a ORIF group as reference group. conversion to THA or redo fixation was 10% and 15%, respectively, at 1 year. Mortality was 14.2% in the ORIF group and 23.6% in the closed reduction group. The higher mortality in the closed reduction group in all likelihood represents their general medical health, which may have precluded surgical intervention. The incidence of PE was 5% in the ORIF group and 2% in the closed reduction group (P,.006). Greater attention needs to be paid to screening and prophylactic treatment for DVT and subsequent PE in this patient population. The authors have no pharmacologic data regarding the DVT prophylaxis used, if any. P P e1068 ORTHOPEDICS Healio.com/Orthopedics

5 Operative Treatment of Acetabular s in the Medicare Population Hayes et al The literature is divided regarding whether ORIF is successful in the treatment of acetabular fractures in the Medicare population. Matta 19 reported inferior results in patients older than 40 years compared with patients younger than 40 years. They found that 65 (68%) of 96 hips in patients older than 40 years had a good or excellent results compared with 134 (81%) of 166 hips in patients younger than 40 years (P5.02). Liebergall et al 20 reported similar inferior results in patients older than 40 years undergoing ORIF for acetabular fractures (mean age, 36.4 years [range, years]). By contrast, Helfet et al 4 found that ORIF can lead to successful outcomes in the elderly population. In a study of 18 patients with a mean age of 67 years (range, years), they found that ORIF is a viable alternative to early THA because only 1 (6%) of 18 patients failed treatment. Moreover, only 2 (12%) of 18 patients developed pulmonary emboli that were subsequently managed with anticoagulation. They reported no incidence of infection or cardiac complications. Their improved results can be attributed to an emphasis placed on the treatment of acetabular fractures and their related complications at their institution. A significant amount of literature has been published regarding the short-term complications of failed ORIF of acetabular fractures converted to THA. Winemaker et al 21 combined the short-term complications from several published studies. In a sample of 341 patients, they found a deep infection rate of 3.8%, a superficial infection rate of 4.5%, a periprosthetic fracture rate of 6.2%, a dislocation rate of 11.4%, an early implant failure rate of 1.5%, and a redo revision rate of 10.9%. In all likelihood, the higher complication rates following conversion to THA reflect the complexity and challenges of surgery in this group of patients. Furthermore, Siebler and Mormino 22 reported 3 complications of ORIF that are specific to the elderly population and offer strategies to reduce the risk of the complications. First, elderly patients with spinal stenosis and foraminal stenosis are more susceptible to sciatic nerve injury during retraction. Ensuring that the hip is flexed and knee extended during posterior exposure can significantly reduce the risk of neurological injury. Second, elderly patients have more inelastic vessels compared with younger patients due to atherosclerosis, making vessel rupture and thrombosis more likely. This can be avoided by using caution when retracting vessels and only using self-retaining retractors when absolutely necessary. Last, nutrition status and osteopenia increase the risk of poor wound healing, infection, and failed fixation in elderly patients. Careful evaluation of nutrition status, use of dietary supplements, and use of secure fixation techniques greatly reduce these risks. The current study has several limitations. The authors have no information about the specific selection criteria used for ORIF in this series. Based on their data, they conclude that patients who underwent ORIF were younger and had few comorbidities, whereas those treated with closed reduction were, in general, elderly and had multiple comorbidities. One could surmise that elderly patients with multiple comorbidities and a probable sedentary lifestyle may have significant risks involved with operative intervention, especially given their osteoporotic and poor bone quality for fixation. In this series, 74% of patients undergoing ORIF were younger than 80 years compared with 43% of patients undergoing closed reduction. Several factors, such as dementia, overall medical health of the patient, and fracture type, are taken into consideration when deciding between ORIF and closed reduction. When comparing the outcomes between the cohorts in the current study, the authors adjusted for differences in demographic characteristics. This study was not designed to compare ORIF and closed reduction of acetabular fractures in elderly patients. The Medicare database is derived from all institutions, including community hospitals, large metropolitan hospitals, and university teaching hospitals. The selection criteria for ORIF vs closed reduction may vary between institutions based on the availability and expertise of the orthopedic trauma surgeons trained to treat this type of fracture pattern. In addition, the authors cannot provide functional data on these patients with respect to baseline functional activities, outcomes measurements, or radiographic analysis with respect to the type of fracture pattern and quality of the fracture reduction. All of these factors contribute to the decision-making process for surgical intervention and predictors of outcomes. 16,17 Despite these limitations and the lack of available data, this study s results demonstrated a high complication incidence and failure rate following operative treatment of acetabular fractures in elderly patients. Acetabular fractures in elderly patients have increased by 29% over the past decade. High mechanical failure rates can be attributed to compromised bone quality leading to loss of fixation with subsequent redo fixation or conversion to THA. The treatment of acetabular fractures in elderly patients is challenging due to the overall compromised health status of patients with advanced age, associated comorbidities, and osteoporotic bone. The data from this study demonstrate that the overall mortality in this group of patients approaches 21.5%, which is similar to patients with hip fractures in general. The incidence of mechanical failure leading to conversion to THA or redo fixation was 10% and 15%, respectively. A high incidence of infection (5.85%), DVT (16.4%), and PE (5.01%) was observed in the ORIF group. Trauma centers treating elderly patients with acetabular fractures need to be aware of the significant risks and complications associated with this group of patients to minimize the incidence of DVT, PE, cardiac risks, and mechanical failure leading to readmission and mortality. AUGUST 2013 Volume 36 Number 8 e1069

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