Stefano A. Bini

Does Discharge Disposition After Primary Total Joint Arthroplasty Affect Readmission Rates

We reviewed 90-day readmission rates for 9150 patients with a primary total hip or knee arthroplasty performed between April 2001 and December 2004. Patients with an American Society of Anesthesiologists score of 3 or greater or with perioperative complications were excluded. We correlated the readmission rate with discharge disposition to either skilled nursing facilities (SNFs) or Home. Of the 9150 patients identified, 1447 were discharged to an SNF. After statistically adjusting for sex, age and American Society of Anesthesiologists scores, total hip arthroplasty and total knee arthroplasty patients discharged to SNFs had higher odds of hospital readmission within 90 days of surgery than those discharged home (total hip arthroplasty: odds ratio = 1.9; 95% confidence interval, 1.2-3.2; P = .008; total knee arthroplasty: odds ratio = 1.6; 95% confidence interval, 1.1-2.4; P = .01). Healthy patients discharged to SNFs after primary total joint arthroplasty need to be followed closely for complications.

Knee replacement: epidemiology, outcomes, and trends in Southern California 17,080 replacements from 1995 through 2004

Background and purpose There are limited popula-tion-based data on utilization, outcomes, and trends in total knee arthroplasty (TKA). The purpose of this study was to examine TKA utilization and short-term outcomes in a pre-paid health maintenance organization (HMO), and to determine whether rates and revision burden changed over time. We also studied whether this population is representative of the general population in California and in the United States. Methods Using hospital utilization and membership databases from 1995 through 2004, we calculated incidence rates (IRs) of primary and revision TKA for every 10,000 health plan members. The demographics of the HMO population were compared to published census data from California and the United States. Results The age and sex distributions of the study population were similar to those of the general population in California and the United States. 15,943 primary TKAs and 1,137 revision TKAs were performed during the 10-year period. Patients below the age of 65 accounted for one-third of all primary replacements and one-third of all revision replacements. IRs of primary TKAs increased from 6.3 per 10,000 in 1995 to 11.0 per 10,000 in 2004, at a rate of 5% per year (p<0.001). IRs of revision TKAs increased from 0.41 per 10,000 in 1995 to 0.74 per 10,000 in 2004 (p=0.4). Revision burden remained stable over the 10-year observation period. Surgical complications were higher in revision TKA than in primary TKA (10% vs. 7.7%; p=0.007). 90day complication rates for primary and revision TKA including death were 0.3% and 0.6% (p=0.1) and for pulmonary embolism 0.5% and 0.4% (p=0.6). 90day re-admission rates for primary and revision TKA including infection were 0.5% and 4.2% (p<0.001), for myocardial infarction 0.1% each, and for pneumonia 0.2% and 0.4% (p=0.08). Interpretation The incidence of primary and revision TKA increased between 1995 and 2005. The rates of postoperative complications were low. Comparisons of the study population and the underlying general populations of interest indicate that this population can be used to predict the incidences and outcomes of TKA in the general population of California and of the United States as a whole.

Surgical Outcomes of Total Knee Replacement According to Diabetes Status and Glycemic Control, 2001 to 2009

BACKGROUND Poor glycemic control in patients with diabetes may be associated with adverse surgical outcomes. We sought to determine the association of diabetes status and preoperative glycemic control with several surgical outcomes, including revision arthroplasty and deep infection. METHODS We conducted a retrospective cohort study in five regions of a large integrated health-care organization. Eligible subjects, identified from the Kaiser Permanente Total Joint Replacement Registry, underwent an elective first primary total knee arthroplasty during 2001 through 2009. Data on demographics, diabetes status, preoperative hemoglobin A1c (HbA1c) level, and comorbid conditions were obtained from electronic medical records. Subjects were classified as nondiabetic, diabetic with HbA1c < 7% (controlled diabetes), or diabetic with HbA1c ≥ 7% (uncontrolled diabetes). Outcomes were deep venous thrombosis or pulmonary embolism within ninety days after surgery and revision surgery, deep infection, incident myocardial infarction, and all-cause rehospitalization within one year after surgery. Patients without diabetes were the reference group in all analyses. All models were adjusted for age, sex, body mass index, and Charlson Comorbidity Index. RESULTS Of 40,491 patients who underwent total knee arthroplasty, 7567 (18.7%) had diabetes, 464 (1.1%) underwent revision arthroplasty, and 287 (0.7%) developed a deep infection. Compared with the patients without diabetes, no association between controlled diabetes (HbA1c < 7%) and the risk of revision (odds ratio [OR], 1.32; 95% confidence interval [CI], 0.99 to 1.76), risk of deep infection (OR, 1.31; 95% CI, 0.92 to 1.86), or risk of deep venous thrombosis or pulmonary embolism (OR, 0.84; 95% CI, 0.60 to 1.17) was observed. Similarly, compared with patients without diabetes, no association between uncontrolled diabetes (HbA1c ≥ 7%) and the risk of revision (OR, 1.03; 95% CI, 0.68 to 1.54), risk of deep infection (OR, 0.55; 95% CI 0.29 to 1.06), or risk of deep venous thrombosis or pulmonary embolism (OR, 0.70; 95% CI, 0.43 to 1.13) was observed. CONCLUSIONS No significantly increased risk of revision arthroplasty, deep infection, or deep venous thrombosis was found in patients with diabetes (as defined on the basis of preoperative HbA1c levels and other criteria) compared with patients without diabetes in the study population of patients who underwent elective total knee arthroplasty.

Giant Cell Tumor of Bone: Curettage and Cement Reconstruction

A retrospective review was conducted of all consecutive giant cell tumors treated by the senior author (JOJ) between 1975 and 1990 using the technique of aggressive curettage through a large bone window followed by acrylic cement reconstruction. Steinmann pins were used as reinforcement bars within the methacrylate in large lesions. Thirty-eight patients with a mean followup of 5.2 years (range, 2-16 years) were identified. Three (8%) recurrences are reported. There were no infections or mechanical failures of the construct. Functional results were good to excellent in 84% of patients. Ninety-five percent of patients reported good or excellent stability, no deformity, and emotional acceptance of the procedure. The recurrence rate with this protocol (8%) approached that associated with wide resection or amputation (0%-5%), and was lower than that seen with simple curettage and bone grafting (27%-55%). Acrylic cement reconstruction is a safe and effective procedure that provides local adjuvant therapy and immediate stability for early rehabilitation. The authors emphasize the importance of aggressive curettage of the lesion through a large bone window and suggest the use of reinforcement bars within the cement for large defects.

Intraepiphyseal resection of the proximal tibia and its impact on lower limb growth.

From 1989 through 1996, 10 children affected by high grade bone tumors of the proximal tibia underwent an intraepiphyseal intercalary resection. The residual epiphyseal bone segment measured less than 2 cm in thickness in all cases and reconstruction always was performed using the combination of a vascularized fibular autograft and a massive bone allograft. The proximal epiphyseal osteosynthesis was fixed by small fragment screws. The aim of this study was to report the growth pattern of the residual proximal tibial epiphysis and to evaluate any possible lower limb discrepancy and/or deformity after the end of skeletal maturity. At current followup six patients were available for the final evaluation. Radiographic documentation included computed tomography scan of both knees before surgery, a panoramic radiographic view and a computed tomography scan of both lower limbs after the end of skeletal growth. The length of both femurs and tibias, the size of the tibial plateau and of the opposite distal femur, and any possible deformity of femur or tibia were measured and compared with the preoperative data. No patient had a limb length discrepancy greater than 3.5 cm. In all cases the ipsilateral femur had a valgus deformity of the hip develop. In two patients this deformity was associated with an elongation of the femur, partially compensating for the shortening of the tibia. The tibial plateau close to reconstruction grew less than the contralateral one (range 2%-8%) but maintained its normal relationship with the distal femur. None of these patients reported any restriction in recreational activities. They could walk, run, and jump. Their functional result according the International Society of Limb Salvage functional grading system was satisfactory in all cases.

Compliant prestress fixation in tumor prostheses: interface retrieval data.

This article reports the first available human retrieval data following the use of a new fixation system for tumor prostheses. The compliant prestress (CPS) fixation system obviates the need for long intramedullary stems. The CPS was designed to provide a stable, high-pressure, motion-free bone-implant interface that would prevent aseptic loosening and allow osseointegration at the bone-implant interface. At 10 months, the fourth patient in the human trial required amputation. Backscatter electron microscopy revealed a buttress of new bone had formed along 70% of the bone-metal interface, with excellent bony ingrowth (average: 42%) into the transverse, porous-coated titanium interface.

Pulmonary Embolism Prophylaxis in More Than 30,000 Total Knee Arthroplasty Patients: Is There a Best Choice?

Prophylaxis for pulmonary embolism (PE) prevention in total knee arthroplasty remains controversial. A joint registry evaluated venous thromboembolism prophylaxis and anesthesia impact on the incidence of PE, fatal PE, and death. Patients received mechanical prophylaxis alone or chemical with or without mechanical prophylaxis. The overall PE incidence was 0.45%; fatal PE, 0.01%; and death, 0.31%. The only significant difference in any outcome was the incidence of PE between Coumadin and mechanical prophylaxis alone. Variables associated with a higher incidence of PE were age, an American Society of Anesthesiologists score of 3 or higher, and the use of general anesthesia. Based on the findings, general anesthesia can be discouraged, and only Coumadin fared better than mechanical prophylaxis alone, whereas other forms of chemical prophylaxis revealed no significant differences.

In vitro testing of a novel limb salvage prosthesis for the distal femur

OBJECTIVE: The aim of this paper was to define strain pattern in the host bone following distal femoral resection and implantation of a massive prosthesis. Two methods of coupling the prosthesis to the bone were compared: the Compliant Pre-Stress device, and a standard cemented tumour prosthesis. DESIGN: The composite femur model was selected to minimize variables. Four femurs were tested before and after implantation. Both coaxial and cantilever loading were applied. BACKGROUND: Cemented distal femoral replacement following resection of malignant tumours has a high failure rate at 5 years and is associated with extensive bone resorption thought to be secondary to stress shielding. METHODS: Strain was measured in the medial and lateral sides at four levels with physiologic loads applied, in the intact, Compliant Pre-Stress, and cemented femurs. Repeated measurements were taken. Strains in the implanted femur were calculated as percentage of the intact, and statistically analyzed. RESULTS: The most reproducible results were noted in cantilever bending (variability <5%). The Compliant Pre-Stress device demonstrated a more physiologic strain pattern than the cemented stem. The most significant difference between the two implants was in the area adjacent to the interface. CONCLUSIONS: The Compliant Pre-Stress device shows less stress shielding than a standard cemented implant. The protocol described and the use of composite femurs demonstrated reproducible results. RELEVANCE: Massive prosthesis are commonly used following tumour resection or removal of failed primary joint replacement prostheses. The failure rate for aseptic loosening for cemented implants is 25% at 5 years with significant bone resorption about the implant. Compliant Pre-Stress is an innovative technology that allows coupling of metallic implants to bone with little stress shielding. This paper aims to define the strain patterns about the implant and compare them to a standard cemented device. The reduced stress shielding of the Compliant Pre-Stress fixation system should guarantee reduced bone loss around the implant and help to obtain improved clinical results.

Prophylaxis Against Pulmonary Embolism in Patients Undergoing Total Hip Arthroplasty

BACKGROUND The optimal method of prophylaxis for the prevention of pulmonary embolism in patients undergoing total hip arthroplasty remains controversial. Guidelines appear to be contradictory. The purpose of the present study was to examine whether a best prophylactic agent exists for the prevention of postoperative pulmonary embolism and whether the type of anesthesia affects the rates of pulmonary embolism. METHODS From 2001 to 2008, a total joint registry from a nationwide health maintenance organization was evaluated to determine the rates of pulmonary embolism, fatal pulmonary embolism, and death among 17,595 patients without a history of venous thromboembolism who were managed with unilateral total hip arthroplasty. All patients were followed for ninety days postoperatively. Data were abstracted electronically and were validated through chart reviews. Multivariate logistic regression models were used to assess associations between the types of prophylaxis and anesthesia that were used and pulmonary embolism while adjusting for other risk factors. RESULTS Patients received either mechanical prophylaxis alone (N = 1533) or chemical prophylaxis (aspirin [N = 934], Coumadin [warfarin] [N = 6063], or low-molecular-weight heparin [N = 7202]) with or without mechanical prophylaxis. The rate of pulmonary embolism was 0.41% (95% confidence interval [CI], 0.32% to 0.51%) overall, 0.37% (95% CI, 0.05% to 0.70%) for mechanical prophylaxis, 0.43% (95% CI, 0.01% to 0.85%) for aspirin, 0.43% (95% CI, 0.26% to 0.59%) for Coumadin, 0.40% (95% CI, 0.26% to 0.55%) for low-molecular-weight heparin, 0.43% (95% CI, 0.28% to 0.58%) for general anesthesia, and 0.40% (95% CI, 0.28% to 0.52%) for non-general anesthesia. The mortality rate was 0.51% (95% CI, 0.40% to 1.01%) overall, 0.67% (95% CI, 0.23% to 1.34%) for mechanical prophylaxis, 0.64% (95% CI, 0.13% to 1.28%) for aspirin, 0.51% (95% CI, 0.33% to 1.02%) for Coumadin, 0.42% (95% CI, 0.27% to 0.83%) for low-molecular-weight heparin, 0.51% (95% CI, 0.35% to 0.67%) for general anesthesia, and 0.50% (95% CI, 0.36% to 0.64%) for non-general anesthesia. Regression models did not show any association between the type of prophylaxis used or the choice of anesthesia and increased odds of pulmonary embolism when adjusting for age, sex, and American Society of Anesthesiologists score. CONCLUSIONS No clinical differences were detected among the types of prophylaxis against venous thromboembolism or the types of anesthesia with respect to pulmonary embolism, fatal pulmonary embolism, or death on the basis of prospective collection of data by a contemporary total joint registry.

Slowing demand for total joint arthroplasty in a population of 3.2 million.

Accurate projections of future demand require constant updates of current data. This article reviews the most recent usage data for primary total joint arthroplasty (TJA) in a community-based hospital system with 3.2 million members. We used administrative databases to determine plan membership, surgical volume, and age-adjusted incidence rates for TJA from 1996 through 2009. The annual growth rate in surgical volume peaked in 2002 at 18% and decreased to 3% by 2009. The annual growth rate for age-adjusted incidence rates peaked in 2002 at 13% and declined to 2% in 2009. In our population, the incidence of TJA continues to rise but at a much slower pace than in recent years.