Evaluation of the Effect of Bariatric Surgery-Induced Weight Loss on Knee Gait and Cartilage Degeneration.

The objective of the study was to investigate the effects of bariatric surgery-induced weight loss on knee gait and cartilage degeneration in osteoarthritis (OA) by combining magnetic resonance imaging (MRI), gait analysis, finite element (FE) modeling, and cartilage degeneration algorithm. Gait analyses were performed for obese subjects before and one-year after the bariatric surgery. FE models were created before and after weight loss for those subjects who did not have severe tibio-femoral knee cartilage loss. Knee cartilage degenerations were predicted using an adaptive cartilage degeneration algorithm which is based on cumulative overloading of cartilage, leading to iteratively altered cartilage properties during OA. The average weight loss was 25.7±11.0 kg corresponding to a 9.2±3.9 kg/m2 decrease in body mass index (BMI). External knee rotation moment increased, and minimum knee flexion angle decreased significantly (p < 0.05) after weight loss. Moreover, weight loss decreased maximum cartilage degeneration by 5±23% and 13±11% on the medial and lateral tibial cartilage surfaces, respectively. Average degenerated volumes in the medial and lateral tibial cartilage decreased by 3±31% and 7±32%, respectively, after weight loss. However, increased degeneration levels could also be observed due to altered knee kinetics. The present results suggest that moderate weight loss changes knee kinetics and kinematics and can slow-down cartilage degeneration for certain patients. Simulation results also suggest that prediction of cartilage degeneration is subject-specific and highly depend on the altered gait loading, not just the patient's weight.

Structure-symptom relationship with wide-area ultrasound scanning of knee osteoarthritis.

The aetiology of knee pain in osteoarthritis (OA) is heterogeneous and its relationship with structural changes and function is unclear. Our goal was to determine the prevalence of wide-area scanned ultrasound-defined knee OA structural features and their association with pain and functional impairment in 79 symptomatic and 63 asymptomatic subjects. All subjects underwent ultrasound knee wide-area scanning and the severity of articular cartilage degeneration, the presence and size of osteophytes, and meniscal extrusion were evaluated. Subjects filled in a self-administrated questionnaire on present knee pain, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) on clinical symptoms and function over the past week. Cartilage changes were the most prevalent followed by lateral meniscal extrusion, osteophytes and medial meniscal extrusion. The global femoral cartilage grade associated strongly with pain and the WOMAC index. Site-specifically, early medial cartilage changes and thinning in sulcus and lateral site were associated with symptoms. The presence of femoral lateral osteophytes was also associated with both outcomes. Using the novel wide-area ultrasound scanning technique, we were able to confirm the negative impact of femoral cartilage OA changes on clinical symptoms. Presence, not necessarily size, of lateral femoral osteophytes was also associated with increased pain and disability.

Comparison of Diagnostic Performance of Semi-Quantitative Knee Ultrasound and Knee Radiography with MRI: Oulu Knee Osteoarthritis Study.

Osteoarthritis (OA) is a common degenerative musculoskeletal disease highly prevalent in aging societies worldwide. Traditionally, knee OA is diagnosed using conventional radiography. However, structural changes of articular cartilage or menisci cannot be directly evaluated using this method. On the other hand, ultrasound is a promising tool able to provide direct information on soft tissue degeneration. The aim of our study was to systematically determine the site-specific diagnostic performance of semi-quantitative ultrasound grading of knee femoral articular cartilage, osteophytes and meniscal extrusion, and of radiographic assessment of joint space narrowing and osteophytes, using MRI as a reference standard. Eighty asymptomatic and 79 symptomatic subjects with mean age of 57.7 years were included in the study. Ultrasound performed best in the assessment of femoral medial and lateral osteophytes, and medial meniscal extrusion. In comparison to radiography, ultrasound performed better or at least equally well in identification of tibio-femoral osteophytes, medial meniscal extrusion and medial femoral cartilage morphological degeneration. Ultrasound provides relevant additional diagnostic information on tissue-specific morphological changes not depicted by conventional radiography. Consequently, the use of ultrasound as a complementary imaging tool along with radiography may enable more accurate and cost-effective diagnostics of knee osteoarthritis at the primary healthcare level.