Faculty Bibliography

INTRODUCTION/BACKGROUND:The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures. METHODS:In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery. RESULTS:In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion. CONCLUSIONS:Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Developing effective treatment for osteoarthritis (OA), a prevalent and disabling disease, has remained a challenge, primarily because of limited understanding of its pathogenesis and late diagnosis. In the subchondral bone, rapid bone loss after traumatic injuries and bone sclerosis at the advanced stage of OA are well-recognized hallmarks of the disease. Recent studies have further demonstrated the crucial contribution of subchondral bone in the development of OA. However, the microstructural basis of these bone changes has not been examined thoroughly, and the paradox of how abnormal resorption can eventually lead to bone sclerosis remains unanswered. By applying a novel microstructural analysis technique, individual trabecula segmentation (ITS), to micro-computed tomography (μCT) images of human OA knees, we have identified a drastic loss of rod-like trabeculae and thickening of plate-like trabeculae that persisted in all regions of the tibial plateau, underneath both severely damaged and still intact cartilage. The simultaneous reduction in trabecular rods and thickening of trabecular plates provide important insights to the dynamic and paradoxical subchondral bone changes observed in OA. Furthermore, using an established guinea pig model of spontaneous OA, we discovered similar trabecular rod loss and plate thickening that preceded cartilage degradation. Thus, our study suggests that rod-and-plate microstructural changes in the subchondral trabecular bone may play an important role in the development of OA and that advanced microstructural analysis techniques such as ITS are necessary in detecting these early but subtle changes. With emerging high-resolution skeletal imaging modalities such as the high-resolution peripheral quantitative computed tomography (HR-pQCT), trabecular rod loss identified by ITS could potentially be used as a marker in assessing the progression of OA in future longitudinal studies or clinical diagnosis. © 2017 American Society for Bone and Mineral Research.

Osteoarthritis (OA) is a prevalent joint disease, yet its pathogenesis remains unclear. Studies have shown that detecting and blocking acute subchondral bone loss associated with traumatic injuries may prevent OA. By applying Individual Trabecula Segmentation (ITS) to muCT scans, we previously identified a loss of trabecular rods in the subchondral trabecular bone as an early and consistent microstructural marker of OA in animal and in human. To examine the potentials of rod loss as a quantitative and reliable biomarker to monitor OA in vivo, the sensitivity of ITS to detect these changes clinically was tested using the second-generation HR-pQCT, a valuable clinical scanner that permits in vivo quantification of trabecular microstructure in the knee. OA (n = 4) and control (n = 4) tibial plateaus were collected from total knee replacement patients and cadavers with no history of metabolic bone disease or fracture. Samples were scanned by muCT at 26-mm voxel size and by HR-pQCT at 61-mm voxel size. Images were registered and thresholded by matching BV/TV between the two resolutions. Cubic trabecular regions were selected from the subchondral bone beneath intact and severely damaged cartilage in OA samples and from corresponding control regions. ITS was used to analyze and compare trabecular morphology between OA and control at both resolutions. High correlation in morphological parameters was found in muCT and HR-pQCT scans. Furthermore, ITS analyses of muCT images and HR-pQCT images consistently reported significant increases in PR ratio in the OA subchondral bone beneath both intact and damaged cartilage. Interestingly, this increase was due to a simultaneous loss of trabecular rods by number and thickening of trabecular plates beneath intact cartilage, while solely due to plate thickening beneath damaged cartilage. Most importantly, despite the reduced resolution of HR-pQCT, ITS was still sensitive to these subtle but dynamic changes in trabecular microstructure. We previously showed that rod loss may be an early signature of OA. This study demonstrates the first attempt to correlate ITS based on 2nd generation HR-pQCT with gold standard muCT, and confirms the sensitivity of ITS to this rod loss at clinical resolution. The combination of ITS and HR-pQCT may serve as a useful tool in identifying early signs of bone loss quantitatively, monitoring microstructural changes in disease progression and identifying the best time window for preventative treatments. (Figure Presented)

BACKGROUND: Perioperative care pathways are tools used in high-volume clinical settings to standardize care, reduce variability, and improve outcomes. However, the mechanism by which the information is transmitted to other caregivers is often inconsistent and error-prone. At our institution, we developed an online, user-editable ("wiki") database to communicate post-operative protocols. The purpose of this study is to evaluate the hypothesis that implementation of the wiki would improve protocol adherence and reduce unintentional deviations inpatient care. METHODS: We conducted a retrospective review of patients who underwent primary lower extremity arthroplasty at our institution during three 6-month time periods including immediately before, 6 months after, and 2 years following introduction of the wiki. Adherence to defined perioperative care pathways (laboratory studies, post-operative imaging, perioperative antibiotics, and inpatient pain medications) was compared between the groups. RESULTS: After wiki implementation, adherence to protocols improved significantly for laboratory orders (P < .0001), imaging (P < .001), pain control regimen (P = .03), and overall protocol adherence (P < .001). Improvements were seen in some areas almost immediately, while others did not show improvements until 2 years after implementation. Costs associated with unnecessary testing were reduced by 82%. CONCLUSION: Development of an online wiki for tracking post-operative protocols improves care pathway adherence and reduces variability in care while lowering costs associated with unnecessary testing, although some benefits may not be immediately realized. Several practical barriers to implementing the wiki are also discussed, along with proposed solutions.

BACKGROUND: The Center for Medicare and Medicaid Services (CMS) has proposed a move to payment based on patient-reported outcomes (PROs), and failure to report on PROs will result in a penalty of 2% in 2016. However, the cost to the physician to collect PROs is not known. METHODS: Using data from the 2013 Medical Group Management Association Compensation and Financial survey and Center for Medicare and Medicaid Services reimbursement, a calculation was performed to determine the cost to the physician to report on PROs for patients undergoing total knee arthroplasty and total hip arthroplasty. Using Medical Group Management Association and Medicare fee for service rates, calculations were performed based on an annual volume of 200 Medicare operative cases (125 total knee arthroplasties, 75 total hip arthroplasties) with 1000 new patients (level 4) and 2000 established patients (level 3) visits. A range of start-up and annual costs necessary to collect PROs including hardware, software, and personnel costs was calculated and then compared with the calculated 2% Medicare penalty for failing to report PROs in 2016. RESULTS: The cost to collect PROs ranged from $47,973 to $56,288 which far outweighed the penalty of $2954 in 2016 for failing to report these measures. CONCLUSION: With the move toward requiring surgeons to report PROs for reimbursement, the current financial model would prove to be cost prohibitive and the incentive to report PROs might be too costly to gain wide acceptance.

BACKGROUND: Hemiarthroplasty (HA) has been a mainstay treatment for displaced femoral neck fractures for many years. The purpose of this study was to report the conversion rate of HA to total hip arthroplasty (THA) for displaced femoral neck fractures and compare outcomes between implant constructs (bipolar vs unipolar), fixation options (cemented vs cementless stems), and age groups (<75 years vs >/=75 years). METHODS: We retrospectively reviewed the results of a consecutive cohort of 686 patients who underwent HA for the treatment of femoral neck fractures at our institution between 1999 and 2013 with a minimum of 2-year follow-up. RESULTS: The overall component revision rate, including conversion to THA, revision HA, revision with open reduction internal fixation, and Girdlestone procedure, was 5.6% (39/686). Seventeen patients (2.5%) were converted from HA to THA at an average of 1.9 years after index procedure. A significantly lower conversion rate of 1.4% (7/499 patients) was found in the older patient cohort (>/=75 years old) compared to 5.3% (11/187) in the younger cohort. The most common causes for conversion surgery to THA were acetabular wear (5 patients), aseptic loosening (4 patients), and periprosthetic fracture (3 patients). There was a significantly lower rate of periprosthetic fracture (0.4% vs 2.5%, P value .025) in the cemented implant group compared to the cementless group. We observed a higher rate of dislocations in the bipolar vs unipolar group (3.8% vs 1%, P value .02) and no other significant differences between these groups. CONCLUSION: We observed a low reoperation rate for this cohort of patients, relatively higher conversion rates for the younger population, fewer periprosthetic fractures with the use of cemented stems, and no advantage of bipolar over unipolar prostheses.

BACKGROUND: The goal of this study was to evaluate the effectiveness of the American Orthopaedic Association's Own the Bone secondary fracture prevention program in the United States. METHODS: The objective of this quality improvement cohort study was dissemination of Own the Bone and implementation of secondary prevention (osteoporosis pharmacologic and bone mineral density [BMD] test recommendations). The main outcome measures were the number of sites implementing Own the Bone and implementation of secondary prevention, i.e., orders for BMD testing and/or pharmacologic treatment. The 177 sites participating in the program were academic and community hospitals, orthopaedic surgery groups, and a health system; data were obtained from the first 125 sites utilizing its registry, between January 1, 2010, and March 31, 2015. It included all patients, aged 50 years or older, presenting with fragility fractures (n = 23,132) who were enrolled in the Own the Bone web-based registry. The interventions were education, development of program elements, dissemination, implementation, and evaluation of the Own the Bone program at participating sites. RESULTS: A growing number of institutions implemented Own the Bone (14 sites in 2005-2006 to 177 sites in 2015). After consultation, 53% of patients had a BMD test ordered and/or pharmacologic therapy for osteoporosis. CONCLUSIONS: The Own the Bone intervention has succeeded in improving the behaviors of medical professionals in the areas of osteoporosis treatment and counseling, BMD testing, initiation of pharmacotherapy, and coordination of care for patients who have experienced a fragility fracture.

BACKGROUND: The purpose of this study is to compare acetabular component version measurements from cross-table lateral (XTL) radiographs, anteroposterior pelvis (AP-P) and anteroposterior hip (AP-H) radiographs, and axial pelvic computed tomography (CT) scans. METHODS: One hundred fifty hips met our inclusion criteria of having a CT, XTL, and AP-P done postoperatively. Version was measured by 2 authors. Pearson regression analysis assessed correlation between versions of the modalities. Analysis of variance testing compared the averages of the values as a whole and based on demographics. When available, comparisons were also done with AP-H radiographs. RESULTS: Mean version for XTL and CT scan was 21.7 degrees and 23.8 degrees , respectively, whereas that from AP-P and AP-H radiographs was 12.5 degrees and 17.2 degrees , respectively. XTL and AP-H version measures were closely correlated with CT (P = .81), whereas AP-P measurements were only moderately correlated with CT (P = .75). AP-P and AP-H were significantly (P < .05) different from CT, whereas XTL was not (P = .36). CONCLUSION: The XTL radiograph remains a useful, cheaper, and safer substitute for CT scan when assessing supine version in the postoperative setting.

BACKGROUND: Significant variability exists across orthopedic surgeons in the management of the displaced femoral neck fracture in the elderly patient (>75 years old). These patients tend to be less healthy, have inferior bone quality, and gait instability leading to increased risk of periprosthetic fracture, compromised implant fixation, dislocation, and need for revision. The surgeon's goals should be to restore mobility while eliminating pain and need for reoperation. METHODS: In this review article, we examine the best available evidence in the literature to determine which strategy achieves optimal outcomes. We examine outcome studies comparing use of hemiarthroplasty and total hip arthroplasty, unipolar and bipolar hemiarthroplasty, and cemented vs cementless fixation of femoral stems. RESULTS AND CONCLUSIONS: For the active, healthy, and lucid patient, or one who has preexisting groin pain, who sustains a displaced femoral neck fracture, the literature supports a total hip arthroplasty. Patients sustaining a displaced femoral neck fracture and who are less active, have decreased bone mass, and are at increased risk of falls would benefit most from a device that optimally balances the need for revision surgery, restores ambulation, and eliminates pain. Thus, the current evidence favors cemented, unipolar hemiarthroplasty for the dependent osteopenic elderly patient with a displaced femoral neck fracture.