G. Segal

Novel classification of knee osteoarthritis severity based on spatiotemporal gait analysis

OBJECTIVE To describe a novel classification method for knee osteoarthritis (OA) based on spatiotemporal gait analysis. METHODS Gait analysis was initially performed on 2911 knee OA patients. Females and males were analyzed separately because of the influence of body height on spatiotemporal parameters. The analysis included the three stages of clustering, classification and clinical validation. Clustering of gait analysis to four groups was applied using the kmeans method. Two-thirds of the patients were used to create a simplified classification tree algorithm, and the models accuracy was validated by the remaining one-third. Clinical validation of the classification method was done by the short form 36 Health Survey (SF-36) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaires. RESULTS The clustering algorithm divided the data into four groups according to severity of gait difficulties. The classification tree algorithm used stride length and cadence as predicting variables for classification. The correct classification accuracy was 89.5%, and 90.8% for females and males, respectively. Clinical data and number of total joint replacements correlated well with severity group assignment. For example, the percentages of total knee replacement (TKR) within 1 year after gait analysis for females were 1.4%, 2.8%, 4.1% and 8.2% for knee OA gait grades 1-4, respectively. Radiographic grading by Kellgren and Lawrence was found to be associated with the gait analysis grading system. CONCLUSIONS Spatiotemporal gait analysis objectively classifies patients with knee OA according to disease severity. That method correlates with radiographic evaluation, the level of pain, function, number of TKR.

312 GENDER AND BODY MASS INDEX PREDICTWOMAC AND QUALITY OF LIFE SCORES IN KNEE OSTEOARTHRITIS

Methods: Data were obtained from information recorded in the medical records of sequential patients who underwent autologous bone-patellar tendon-bone graft ACL reconstruction by one of us (Levy) during the years 2003-2005. Injury to specific articular structures, as well as the effects of age, height, weight, body mass index (BMI), occupation, tobacco and alcohol use, gender, and timing of surgery relevant to the date of injury were assessed. Results: Eighty-six patients who underwent this procedure for ACL reconstruction were analyzed. Among them, 24 patients had medial meniscal tears (most commonly partial thickness, longitudinal and bucket handle tears in the posterior horns), 15 had lateral meniscal tears (most commonly radial and longitudinal tears in the posterior horns), and 7 had tears in both menisci. Nineteen patients suffered chondral injuries: 3 in the lateral femoral condyle, 8 in the patella, 9 in the medial femoral condyle, and 3 in the trochlea. Obese patients, (defined as a BMI of 30 or over), had an increased risk for patellar chondral lesions (2.3% versus 31.3%). Surgical delay greater than a year was associated with an increased risk for medial meniscal tears (29.7% versus 75%), but not lateral meniscal tears, as well as medial femoral condyle injuries (6.8% versus 33.3%). Patients over the age of 25 were more likely to have medial femoral condyle lesions (2.5% versus 17.4%). Gender, height, weight, occupation, and use of alcohol or tobacco showed no effect on chondral or meniscal injuries in patients with ACL tears. Conclusion: The observations recorded on this group of patients are very similar to those recorded by other orthopedic surgeons who have attempted to map meniscal and chondral lesions observed at the time of ACL repair procedures (Slauterbeck et al., 2009, Kaeding et al., 2005). The correspondence among these recordings supports their accuracy. Therefore, among patient groups with identical surgical interventions, it seems reasonable to undertake a large-scale study correlating recordings of initial injury patterns with biomarkers of cartilage extracellular matrix turnover, imaging studies of the menisci and cartilage, and clinical features of OA at 5 to 15 years of follow-up as a means of testing the hypothesis.

125 DO FEMALE GAIT PATTERNS DIFFER FROM MALE GAIT PATTERNS IN KNEE OSTEOARTHRITIS

width with LWAS could be another mechanism for the further reduction of the moment with that type of insole. The analyses of biomechanical parameters at subtalar joints revealed that the change of valgus angle at the joints was smaller with LWAS than with LW, while the magnitude of subtalar adduction moment was similar for LW and LWAS. This may indicate that LWAS could allow the subject to walk in a more natural manner, while exerting load shift similar to that with LW. Conclusions: The addition of an arch support to the laterally wedged insole reduced knee adduction moment more efficiently than the conventional laterally wedged insoles, presumably through the reduction of the toe-out angle and step width. Current results also indicated that the conventional laterally wedged insole could have potential drawbacks to induce toe-out gait with wider stance, which might impair its biomechanical effects. The result of insole therapy for medial knee OA could be significantly improved by the addition of an arch support to the laterally wedged insole.