Computational biomechanics to simulate the femoropopliteal intersection during knee flexion: a preliminary study

To assess if finite element (FE) models can be used to predict deformation of the femoropopliteal segment during knee flexion.

All cause and disease specific mortality in patients with knee or hip osteoarthritis: population based cohort study

Objective To examine all cause and disease specific mortality in patients with osteoarthritis of the knee or hip. Design Population based cohort study. Setting General practices in the southwest of England. Participants 1163 patients aged 35 years or over with symptoms and radiological confirmation of osteoarthritis of the knee or hip. Main outcome measures Age and sex standardised mortality ratios and multivariable hazard ratios of death after a median of 14 years’ follow-up. Results Patients with osteoarthritis had excess all cause mortality compared with the general population (standardised mortality ratio 1.55, 95% confidence interval 1.41 to 1.70). Excess mortality was observed for all disease specific causes of death but was particularly pronounced for cardiovascular (standardised mortality ratio 1.71, 1.49 to 1.98) and dementia associated mortality (1.99, 1.22 to 3.25). Mortality increased with increasing age (P for trend <0.001), male sex (adjusted hazard ratio 1.59, 1.30 to 1.96), self reported history of diabetes (1.95, 1.31 to 2.90), cancer (2.28, 1.50 to 3.47), cardiovascular disease (1.38, 1.12 to 1.71), and walking disability (1.48, 1.17 to 1.86). However, little evidence existed for increased mortality associated with previous joint replacement, obesity, depression, chronic inflammatory disease, eye disease, or presence of pain at baseline. The more severe the walking disability, the higher was the risk of death (P for trend <0.001). Conclusion Patients with osteoarthritis are at higher risk of death compared with the general population. History of diabetes, cancer, or cardiovascular disease and the presence of walking disability are major risk factors. Management of patients with osteoarthritis and walking disability should focus on effective treatment of cardiovascular risk factors and comorbidities, as well as on increasing physical activity.

Endovascular Revascularization of Below-the-Knee Arteries: Prospective Short-Term Angiographic and Clinical Follow-up

PURPOSE: To evaluate arterial lesion characteristics and their impact on angiographic and clinical outcomes after endovascular below-the-knee (BTK) revascularization. MATERIALS AND METHODS: Between April 2008 and June 2009, 33 patients (mean age 74.9 years) with 34 limbs and 50 arterial segments (mean lesion length 59.3 mm) undergoing endovascular BTK revascularization agreed to undergo prospective clinical and intraarterial angiographic 6-month follow-up evaluation. Clinical indication for BTK revascularization was critical limb ischemia (CLI) in 18 patients and delayed wound healing without hemodynamic evidence of CLI and intermittent claudication (IC) in 15 patients. RESULTS: Binary restenosis was observed in 40% of treated segments at 6 months. Primary sustained clinical improvement was 82.4% and 55.9% at 3 months and 6 months. Lesion length was independently associated with binary restenosis (hazard ratio [HR] 1.013, 95% confidence interval [CI] 1.000-1.016, P = .05) and lower rates of primary sustained clinical improvement (HR 1.024, 95% CI 1.006-1.042, P = .008). CONCLUSIONS: Endovascular BTK revascularization yields clinical and angiographic benefits both for patients with IC and for patients with CLI. Although arterial lesion length adversely affects angiographic and clinical outcomes after endovascular revascularization, limb salvage rates were substantially higher compared with the comparatively low patency rates after BTK angioplasty.

International survey of primary and revision total knee replacement

Purpose Total knee arthroplasty (TKA) is currently the international standard of care for treating degenerative and rheumatologic knee joint disease, as well as certain knee joint fractures. We sought to answer the following three research questions: (1) What is the international variance in primary and revision TKA rates around the world? (2) How do patient demographics (e.g., age, gender) vary internationally? (3) How have the rates of TKA utilization changed over time? Methods The survey included 18 countries with a total population of 755 million, and an estimated 1,324,000 annual primary and revision total knee procedures. Ten national inpatient databases were queried for this study from Canada, the United States, Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, and Switzerland. Inpatient data were also compared with published registry data for eight countries with operating arthroplasty registers (Denmark, England & Wales, Norway, Romania, Scotland, Sweden, Australia, and New Zealand). Results The average and median rate of primary and revision (combined) total knee replacement was 175 and 149 procedures/100,000 population, respectively, and ranged between 8.8 and 234 procedures/100,000 population. We observed that the procedure rate significantly increased over time for the countries in which historical data were available. The compound annual growth in the incidence of TKA ranged by country from 5.3% (France) to 17% (Portugal). We observed a nearly 27-fold range of TKA utilization rates between the 18 different countries included in the survey. Conclusion It is apparent from the results of this study that the demand for TKA has risen substantially over the past decade in countries around the world.

Age at hip or knee joint replacement surgery predicts likelihood of revision surgery

We compared revision and mortality rates of 4668 patients undergoing primary total hip and knee replacement between 1989 and 2007 at a University Hospital in New Zealand. The mean age at the time of surgery was 69 years (16 to 100). A total of 1175 patients (25%) had died at follow-up at a mean of ten years post-operatively. The mean age of those who died within ten years of surgery was 74.4 years (29 to 97) at time of surgery. No change in comorbidity score or age of the patients receiving joint replacement was noted during the study period. No association of revision or death could be proven with higher comorbidity scoring, grade of surgeon, or patient gender. We found that patients younger than 50 years at the time of surgery have a greater chance of requiring a revision than of dying, those around 58 years of age have a 50:50 chance of needing a revision, and in those older than 62 years the prosthesis will normally outlast the patient. Patients over 77 years old have a greater than 90% chance of dying than requiring a revision whereas those around 47 years are on average twice as likely to require a revision than die. This information can be used to rationalise the need for long-term surveillance and during the informed consent process.

Anterior knee pain after total knee arthroplasty: does it correlate with patellar blood flow?

Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause of postoperative anterior knee pain. We examine whether disrupted patellar blood flow correlates with anterior knee pain following TKA.

Biochemical (T2, T2* and magnetisation transfer ratio) MRI of knee cartilage: feasibility at ultra-high field (7T) compared with high field (3T) strength

This study compares the performance and the reproducibility of quantitative T2, T2* and the magnetisation transfer ratio (MTR) of articular cartilage at 7T and 3T.

Automatic Scan Planning for Magnetic Resonance Imaging of the Knee Joint

Automatic scan planning for magnetic resonance imaging of the knee aims at defining an oriented bounding box around the knee joint from sparse scout images in order to choose the optimal field of view for the diagnostic images and limit acquisition time. We propose a fast and fully automatic method to perform this task based on the standard clinical scout imaging protocol. The method is based on sequential Chamfer matching of 2D scout feature images with a three-dimensional mean model of femur and tibia. Subsequently, the joint plane separating femur and tibia, which contains both menisci, can be automatically detected using an information-augmented active shape model on the diagnostic images. This can assist the clinicians in quickly defining slices with standardized and reproducible orientation, thus increasing diagnostic accuracy and also comparability of serial examinations. The method has been evaluated on 42 knee MR images. It has the potential to be incorporated into existing systems because it does not change the current acquisition protocol.

Laser-assisted lipolysis for knee remodelling: A prospective study in 30 patients

Unsightly fat knees are a frustrating aesthetic deformity exacerbated by genetic predisposition and resistance to diet. This article reports our experience with laser-assisted lipolysis (LAL) in knee remodelling.