High variability in patient reported outcome utilization following hip fracture: a potential barrier to value-based care.

For patients with hip fractures, outcomes can be measured by giving surveys measuring "patient rated outcome measures" (PROMs), performance based measures (PBMS), and objective medical outcomes (e.g., mortality, living situation, resource utilization). This study reviewed articles on hip fracture published in top academic journals, and found that most studies are not reliably using a single set of outcome measures including PROMs, and no single PROM or outcome battery is being used commonly. PURPOSE/INTRODUCTION: Osteoporotic hip fractures are associated with high levels of morbidity, mortality, and cost, while gains in mortality over the past 30 years have been modest. To improve care beyond simple mortality metrics requires identifying and then consistently measuring outcomes that are meaningful to patients and families. The purpose of this study was to review the top-tier hip fracture literature published in the past 30 years to determine if there are consensus outcome measures being routinely used and if the rate of reporting clinically meaningful patient-rated outcome measures is improving over time. METHODS: This was a systematic review and meta-analysis on outcome measures reported in osteoporotic hip fractures. Articles were included if they had been published over the last 30 years and were from high impact factor journals. Inclusion criteria were elderly hip fractures, therapeutic or prognostic study, unique and identifiable patients, and included follow-up beyond initial hospitalization. We analyzed study type, inclusion criteria, outcomes reported, and journal specialty orientation. RESULTS: Three hundred eighty-four articles were included in the final analysis. Sixty-seven percent of the articles were therapeutic studies; 33% were prognostic studies. The average number of patients in each study was 435; the average age was 78 years. The most commonly reported outcome was mortality, and was present in 79% of studies. There was a high degree of heterogeneity in patient-reported outcome measures, with the most popular score (Harris Hip Score) reported only 14% of the time. Only 6% of articles had all components of essential core outcome sets previously defined in the literature. CONCLUSIONS: Despite the apparent advances that have been made in our ability to care for hip fractures, the overall rate of reporting outcomes beyond mortality rate remains low. This lack of consensus represents a major barrier to implementation of value-based care in this patient population.

Do Metaphyseal Cones and Stems Provide Any Biomechanical Advantage for Moderate Contained Tibial Defects in Revision TKA? A Finite-Element Analysis Based on a Cadaver Model.

BACKGROUND: Satisfactory management of bone defects is important to achieve an adequate reconstruction in revision TKA. Metaphyseal cones to address such defects in the proximal tibia are increasingly being used; however, the biomechanical superiority of cones over traditional techniques like fully cementing the implant into the defect has not yet been demonstrated. Moreover, although long stems are often used to bypass the defects, the biomechanical efficacy of long stems compared with short, cemented stems when combined with metaphyseal cones remains unclear. QUESTIONS/PURPOSES: We developed and validated finite-element models of nine cadaveric specimens to determine: (1) whether using cones for addressing moderate metaphyseal tibial defects in revision TKA reduces the risk of implant-cement debonding compared with cementing the implant alone, and (2) when using metaphyseal cones, whether long, uncemented stems (or diaphyseal-engaging stems) reduce the risk of implant-cement debonding and the cone-bone micromotions compared with short, cemented stems. METHODS: We divided nine cadaveric specimens (six male, three female, aged 57 to 73 years, BMI 24 to 47 kg/m2) with standardized tibial metaphyseal defects into three study groups: no cone with short (50-mm) cemented stem, in which the defect was filled with cement; cone with short (50-mm) cemented stem, in which a metaphyseal cone was implanted before cementing the implant; and cone with long, diaphyseal-engaging stem, which received a metaphyseal cone and the largest 150-mm stem that could fit the diaphyseal canal. The specimens were implanted and mechanically tested. Then, we developed and validated finite-element models to investigate the interaction between the implant and the bone during the demanding activity of stair ascent. We quantified the risk of implant debonding from the cement mantle by comparing the axial and shear stress at the cement-implant interface against an experimentally derived interface failure index criterion that has been previously used to quantify the risk of cement debonding. We considered the risk of debonding to be minimal when the failure index was below 10% of the strength of the interface (or failure index < 0.1). We also quantified the micromotion between the cone and the bone, as a guide to the likelihood of fixation by bone ingrowth. To this end, we assumed bone ingrowth for micromotion values below the most restrictive reported threshold for bone ingrowth, 20 µm. RESULTS: When using a short, 50-mm cemented stem and cement alone to fill the defect, 77% to 86% of the cement-implant interface had minimal risk of debonding (failure index < 0.1). When using a short, 50-mm cemented stem with a cone, 87% to 93% of the cement-implant interface had minimal debonding risk. When combining a cone with a long (150-mm) uncemented stem, 92% to 94% of the cement-implant interface had minimal debonding risk. The differences in cone-bone micromotion between short, cemented stems and long, uncemented stems were minimal and, for both configurations, most cones had micromotions below the most restrictive 20-µm threshold for ingrowth. However, the maximum micromotion between the cone and the bone was in general smaller when using a long, uncemented stem (13-23 µm) than when using a short, cemented stem (11-31 µm). CONCLUSION: Although the risk of debonding was low in all cases, metaphyseal cones help reduce the biomechanical burden on the implant-cement interface of short-stemmed implants in high-demand activities such as stair ascent. When using cones in revision TKA, long, diaphyseal-engaging stems did not provide a clear biomechanical advantage over short stems. Future studies should explore additional loading conditions, quantify the interspecimen variability, consider more critical defects, and evaluate the behavior of the reconstructive techniques under repetitive loads. CLINICAL RELEVANCE: Cones and stems are routinely used to address tibial defects in revision TKA. Despite our finding that metaphyseal cones may help reduce the risk of implant-cement debonding and allow using shorter stems with comparable biomechanical behavior to longer stems, either cones or cement alone can provide comparable results in contained metaphyseal defects. However, longer term clinical studies are needed to compare these techniques over time.

Location of the Popliteal Artery in Knee Extension on Magnetic Resonance Imaging.

The goal of this study was to define the course of the popliteal artery (PA) and determine any variability among different patient demographics; by identifying risk factors for injury, surgeons can decrease patient morbidity and mortality. Ninety-four adult magnetic resonance imaging studies of the knee were reviewed. In extension, the artery is at most 7.87 mm posterior and 4.83 mm lateral to the midline below the tibial plateau. Proximally, the artery is more anterior and midline. With increasing body mass indexes, the artery is more posterior at any level. At the femur, 1 cm above the distal articular surface, the artery was more posterior in younger patients; 1 cm below the joint line, it was more posterior in elder patients. Attention should be given during total knee arthroplasty, revision surgery, lateral meniscal repair, posterior cruciate ligament reconstruction, high tibial osteotomy, and fixation of tibial tubercle fractures. Proximally, the PA is more anterior and midline, placing it at significant risk during these procedures. (Journal of Surgical Orthopaedic Advances 27(4):325-328, 2018).

Total Knee Arthroplasty in Obesity: In-Hospital Outcomes and National Trends.

BACKGROUND: Both the prevalence of obesity and the utilization rate of total knee arthroplasty are increasing. The rate and proportion of total knee arthroplasty (TKA) performed in the setting of obesity/morbid obesity is increasing significantly over time. METHODS: Using International Classification of Diseases-Ninth Revision codes, we searched the National Hospitals Discharge Survey national database for patients admitted for primary TKA between 2001 and 2010. We then used International Classification of Diseases-Ninth Revision codes for obesity (body mass index = 30-40 kg/m2) and morbid obesity (body mass index, ≥ 40 kg/m2) to select the obese cohorts. RESULTS: We found 29,694 nonobese, 2645 obese, and 1150 morbidly obese patients. There was an increase in each group over time. The rate of obesity/morbid obesity was strongly correlated with time. Obese and morbidly obese patients were more likely to be younger, female, diabetic, and have Medicaid than nonobese patients. Obese and morbidly obese patients had shorter hospital stays and higher home discharge rates than nonobese patients. Obese and morbidly obese patients had lower transfusion rates, shorter hospital stays, and no increase in inpatient wound infection or venous thromboembolic complications than nonobese patients. The Midwest region saw a greater burden of obese TKA patients. CONCLUSION: With the right measures and precautions, satisfactory inhospital outcomes are possible in the obese patient after primary TKA. A limitation of this study is short inhospital stay of the index procedure as complications may present later after discharge.

What Protects Certain Nerves from Stretch Injury?

The human tibial nerves is less prone to injury following joint arthroplasty compared with the peroneal nerves. Besides the anatomical distribution, other features may confer protection from stretch injury. We therefore examined the size, shape and connective tissue distribution for the two nerves. The tibial and peroneal nerves from each side of nine fresh human cadavers we reharvested mid-thigh. Proximal segments manually stretched 20%-25% were fixed in aldehyde, while the adjacent distal segments were fixed in their natural length. Paraffin sections stained by Masson's trichrome method for connective tissue were examined by light microscopy. Tibial nerves had 2X more fascicles compared with the peroneal, but the axonal content appeared similar. Analysis showed that neither nerve had a significant reduction in cross sectional area of the fascicles following stretch. However, fascicles from stretched tibial nerves become significantly more oval compared with those from unstretched controls and peroneal nerves. Tibial nerves had a greater proportion that was extrafascicular tissue (50-55%) compared with peroneal nerves (38%-42%). This epineurium was typically adipose tissue. Perineurial thickness in both nerves was directly related to fascicular size. Tibial nerves have several unique histological features associated with size, shape and tissue composition compared with the peroneal nerve. We suggest that more fascicles with their tightly bound perineurium and more robust epineurium afford protection against stretch injury. Mechanical studies should clarify how size and shape contribute to nerve protection and/or neurapraxia.