The effects of total knee arthroplasty on physical functioning and health among the under age 65 population

Magnetic Resonance Safety Evaluation of a Novel Alumina Matrix Composite Ceramic Knee and Image Artifact Comparison to a Metal Knee Implant of Analogous Design

Background

Image artifacts caused by metal knee implants in 1.5T and 3T magnetic resonance imaging (MRI) systems complicate imaging-based diagnosis of the peri-implant region after total knee arthroplasty. Alternatively, metal-free knee prostheses could effectively minimize MRI safety hazards and offer the potential for higher quality diagnostic images.

Methods

A novel knee arthroplasty device composed of BIOLOX delta, an alumina matrix composite (AMC) ceramic, was tested in a magnetic resonance (MR) environment. American Society for Testing and Materials test methods were used for evaluating magnetically induced displacement force, magnetically induced torque, radiofrequency-induced heating, and MR image artifact.

Results

Magnetically induced displacement force and magnetically induced torque results of the AMC ceramic knee indicated that these effects do not pose a known risk in a clinical MR environment, as assessed in a 3T magnetic field. Moreover, minimal radiofrequency-induced heating of the device was observed. In addition, the AMC ceramic knee demonstrated minimal MR image artifacts (7 mm) in comparison to a cobalt-chromium knee (88 mm). The extremely low magnetic susceptibility of AMC (2 ppm) underlines that it is a nonmetallic and nonmagnetic material well suited for the manufacturing of MR Safe orthopaedic implants.

Conclusions

The AMC ceramic knee is a novel metal-free total knee arthroplasty device that can be regarded as MR Safe, as suggested by the absence of hazards from the exposure of this implant to a MR environment. The AMC ceramic knee presents the advantage of being scanned with superior imaging results in 3T MRI systems compared to alternative metal implants on the market.

Highlighting the advantages and benefits of cementless total knee arthroplasty (Review)

In the field of orthopedic surgery, cemented total knee arthroplasty (TKA) is considered to be one of the gold standards. However, there are categories of patients (i.e., obese and morbidly obese patients, younger than 65 years old) among whom cemented TKA has however a high failure rate. Moreover, the frequency of using uncemented TKA is increasing due to the potential benefits of long-term biological fixation, being an innovative field that addresses a new generation orthopedic surgical treatment which is more suitable for young patients who have good bone quality (good to very good, in terms of density). The survival rates and functional results of the latest generation of cementless TKAs may be similar to functional results and survival rates of cemented prosthesis. In conclusion, this review-type article can be considered a powerful database, extremely informative, dense, and focused on the topic mentioned above, in the interest of all medical professionals and all interested individuals.

Budgetary Consequences of High Medical Spending Across Age and Social Status: Evidence from the Consumer Expenditure Surveys

BACKGROUND AND OBJECTIVES

This study examines high medical spending among younger, midlife, and older households.

RESEARCH DESIGN AND METHODS

We investigate high medical spending using data from the 2010 through March 2018 Consumer Expenditures Surveys (n = 92,951). We classify and describe high medical spenders relative to others within three age groups (household heads age 25-44, 45-64, and 65+) using finite mixture models and multinomial logistic regression, respectively. We then use hierarchical linear models to estimate the effects of high medical spending on nonmedical spending.

RESULTS

Among younger households, high medical spending is positively associated with higher education and increased spending on housing and food. Among older households, high medical spending is associated with lower education and decreased nonmedical spending.

DISCUSSION AND IMPLICATIONS

Earlier in the life course, high medical spending is more likely to indicate an investment in future household well-being, while at older ages, high medical spending is likely to indicate medical consumption.

Characteristics of young and lower functioning patients following total knee arthroplasty: a retrospective study

BACKGROUND

Rates of total knee arthroplasty (TKA) procedures in younger, more medically complex patients have dramatically increased over the last several decades. No study has examined categorization of lower and higher functioning subgroups within the TKA patient population. Our study aimed to determine preoperative characteristics of younger patients who are lower functioning following TKA.

METHODS

Patients were categorized into higher and lower functioning subgroups defined using a median split of 1) postoperative Timed Up and Go (TUG) test times and 2) Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale scores. A split in age (65 years) was used to further classify patients into four categories: younger lower functioning, younger higher functioning, older lower functioning and older higher functioning. Measures from preoperative domains of health, psychological, physical performance and pain severity were examined for between-group differences.

RESULTS

Comparing mean values, the younger lower functioning subgroup using the TUG had significantly weaker knee extensor, slower gait speed, higher body mass index and greater pain compared to other subgroups. The younger lower functioning subgroup using the WOMAC physical function subscale demonstrated higher pain levels and Coping Strategies Questionnaire-Catastrophizing Subscale scores compared to the older lower functioning subgroup.

CONCLUSIONS

Poorer preoperative physical performance and pain severity appear to have the largest influence on early postoperative TKA recovery in younger lower functioning patients relative to both younger and older higher functioning patients.

Knee Disarticulation for a Total Knee Arthroplasty Periprosthetic Fracture

Total knee arthroplasty, although a very successful surgery, can present the patient with several potential complications, including the risk for periprosthetic fractures. Complications involving periprosthetic fractures after total knee arthroplasty can present a complex clinical scenario for orthopedic surgeons. To date, adequate literature exists to guide surgeons in approaching most periprosthetic fractures; however, standard operating procedure can fall short when confronted with more complex clinical scenarios. The authors present an alternative approach, falling outside the traditional paradigm, to addressing a periprosthetic tibial fracture in the setting of a previous total knee arthroplasty. Given both the patient's physiological factors and the inherent factors of the fracture, the authors found that the first-line treatments for periprosthetic fracture, including open reduction and internal fixation and joint revision, were inadequate and posed more potential risks than benefits for the patient. In light of this situation, the authors elected to treat this patient's periprosthetic fracture with a through knee amputation, as this provided the patient with the lowest cost in morbidity while still addressing the fracture. [Orthopedics. 2016; 39(4):e775-e778.].

Hyaluronic Acid Injections Are Associated with Delay of Total Knee Replacement Surgery in Patients with Knee Osteoarthritis: Evidence from a Large U.S. Health Claims Database

BACKGROUND

The growing prevalence of osteoarthritis (OA) and the medical costs associated with total knee replacement (TKR) surgery for end-stage OA motivate a search for agents that can delay OA progression. We test a hypothesis that hyaluronic acid (HA) injection is associated with delay of TKR in a dose-dependent manner.

METHODS AND FINDINGS

We retrospectively evaluated records in an administrative claims database of ~79 million patients, to identify all patients with knee OA who received TKR during a 6-year period. Only patients with continuous plan enrollment from diagnosis until TKR were included, so that complete medical records were available. OA diagnosis was the index event and we evaluated time-to-TKR as a function of the number of HA injections. The database included 182,022 patients with knee OA who had TKR; 50,349 (27.7%) of these patients were classified as HA Users, receiving ≥1 courses of HA prior to TKR, while 131,673 patients (72.3%) were HA Non-users prior to TKR, receiving no HA. Cox proportional hazards modelling shows that TKR risk decreases as a function of the number of HA injection courses, if patient age, gender, and disease comorbidity are used as background covariates. Multiple HA injections are therefore associated with delay of TKR (all, P < 0.0001). Half of HA Non-users had a TKR by 114 days post-diagnosis of knee OA, whereas half of HA Users had a TKR by 484 days post-diagnosis (χ2 = 19,769; p < 0.0001). Patients who received no HA had a mean time-to-TKR of 0.7 years; with one course of HA, the mean time to TKR was 1.4 years (χ2 = 13,725; p < 0.0001); patients who received ≥5 courses delayed TKR by 3.6 years (χ2 = 19,935; p < 0.0001).

CONCLUSIONS

HA injection in patients with knee OA is associated with a dose-dependent increase in time-to-TKR.