The main goal of this study was to estimate the variability of gait parameters (angular changes) in patients after cruciate-retaining and cruciate-substituting total knee arthroplasties. Angular changes of the knee joint in three planes were taken into consideration. The three-dimensional analysis of locomotion pattern was carried out on 18 patients aged 60-74, using the Vicon system. 8 patients were after posterior cruciate-retaining (CR) total knee arthroplasty and 10 after posterior-stabilized (PS) arthroplasty. The control group consisted of 30 healthy subjects 50-70 years old. The results showed, that CR patients walked on flexed knees and the varus alignment in stance phase was observed. Increased internal rotation was also visible. The movement analysis of PS knee joints was similar to CR group but the angular changes in frontal and transversal planes were more increased compared to the norm.

BACKGROUND: Many patients report symptomatic relief after undergoing arthroscopy of the knee for osteoarthritis, but it is unclear how the procedure achieves this result. We conducted a randomized, placebo-controlled trial to evaluate the efficacy of arthroscopy for osteoarthritis of the knee. METHODS: A total of 180 patients with osteoarthritis of the knee were randomly assigned to receive arthroscopic débridement, arthroscopic lavage, or placebo surgery. Patients in the placebo group received skin incisions and underwent a simulated débridement without insertion of the arthroscope. Patients and assessors of outcome were blinded to the treatment-group assignment. Outcomes were assessed at multiple points over a 24-month period with the use of five self-reported scores--three on scales for pain and two on scales for function--and one objective test of walking and stair climbing. A total of 165 patients completed the trial. RESULTS: At no point did either of the intervention groups report less pain or better function than the placebo group. For example, mean (+/-SD) scores on the Knee-Specific Pain Scale (range, 0 to 100, with higher scores indicating more severe pain) were similar in the placebo, lavage, and débridement groups: 48.9+/-21.9, 54.8+/-19.8, and 51.7+/-22.4, respectively, at one year (P=0.14 for the comparison between placebo and lavage; P=0.51 for the comparison between placebo and débridement) and 51.6+/-23.7, 53.7+/-23.7, and 51.4+/-23.2, respectively, at two years (P=0.64 and P=0.96, respectively). Furthermore, the 95 percent confidence intervals for the differences between the placebo group and the intervention groups exclude any clinically meaningful difference. CONCLUSIONS: In this controlled trial involving patients with osteoarthritis of the knee, the outcomes after arthroscopic lavage or arthroscopic débridement were no better than those after a placebo procedure.

OBJECTIVE: To test the hypothesis that dynamic load at baseline can predict radiographic disease progression in patients with medial compartment knee osteoarthritis (OA). METHODS: During 1991-93 baseline data were collected by assessment of pain, radiography, and gait analysis in 106 patients referred to hospital with medial compartment knee OA. At the six year follow up, 74 patients were again examined to assess radiographic changes. Radiographic disease progression was defined as more than one grade narrowing of minimum joint space of the medial compartment. RESULTS: In the 32 patients showing disease progression, pain was more severe and adduction moment was higher at baseline than in those without disease progression (n=42). Joint space narrowing of the medial compartment during the six year period correlated significantly with the adduction moment at entry. Adduction moment correlated significantly with mechanical axis (varus alignment) and negatively with joint space width and pain score. Logistic regression analysis showed that the risk of progression of knee OA increased 6.46 times with a 1% increase in adduction moment. CONCLUSIONS: The results suggest that the baseline adduction moment of the knee, which reflects the dynamic load on the medial compartment, can predict radiographic OA progression at the six year follow up in patients with medial compartment knee OA.

OBJECTIVE: To assess the effect of a home based exercise programme, designed to improve quadriceps strength, on knee pain and disability. METHODS: 191 men and women with knee pain aged 40-80 were recruited from the community and randomised to exercise (n = 113) or no intervention (n = 78). The exercise group performed strengthening exercises daily for six months. The primary outcome measure was change in knee pain (Western Ontario McMaster Osteoarthritis index (WOMAC)). Secondary measures included visual analogue scales (VAS) for pain on stairs and walking and WOMAC physical function scores. RESULTS: WOMAC pain score reduced by 22.5% in the exercise group and by 6.2% in the control group (between group difference p < 0.05, unpaired t test). VAS scores for pain also reduced in the exercise group compared with the control group (p < 0.05). Physical function scores reduced by 17.4% in the exercise group and were unchanged in controls (p < 0.05). CONCLUSION: A simple programme of home quadriceps exercises can significantly improve self reported knee pain and function.

This study tested whether the peak external knee adduction moments during walking in subjects with knee osteoarthritis (OA) were correlated with the mechanical axis of the leg, radiographic measures of OA severity, toe out angle or clinical assessments of pain, stiffness or function. Gait analysis was performed on 62 subjects with knee OA and 49 asymptomatic control subjects (normal subjects). The subjects with OA walked with a greater than normal peak adduction moment during early stance (p = 0.027). In the OA group, the mechanical axis was the best single predictor of the peak adduction moment during both early and late stance (R = 0.74, p < 0.001). The radiographic measures of OA severity in the medial compartment were also predictive of both peak adduction moments (R = 0.43 to 0.48, p < 0.001) along with the sum of the WOMAC subscales (R =-0.33 to -0.31, p < 0.017). The toe out angle was predictive of the peak adduction moment only during late stance (R =-0.45, p < 0.001). Once mechanical axis was accounted for, other factors only increased the ability to predict the peak knee adduction moments by 10 18%. While the mechanical axis was indicative of the peak adduction moments, it only accounted for about 50% of its variation, emphasizing the need for a dynamic evaluation of the knee joint loading environment. Understanding which clinical measures of OA are most closely associated with the dynamic knee joint loads may ultimately result in a better understanding of the disease process and the development of therapeutic interventions.

OBJECTIVE: To test the hypothesis that sex-related and joint compartment-related differences in the risk of osteoarthritis (OA) of the knee might be associated with variations in cartilage development, we investigated knee cartilage volume in healthy children. METHODS: We studied 92 children who were randomly selected from among students in grades 3-12 of a single school in Hobart, Tasmania (49 boys, 43 girls; age range 9-18 years). Articular cartilage thickness and volume were determined at the patella, medial tibial compartment, and lateral tibial compartment by magnetic resonance imaging (MRI). Sagittal T1-weighted fat-suppressed MRI images were obtained and processed on an independent computer work station. RESULTS: Males had significantly more knee cartilage than females. Sex accounted for 6-36% of the variation in cartilage thickness and volume, which was statistically significant at all sites. Even after adjustment for age, body mass index, bone area, and physical activity, males had 16-31% higher cartilage volume; this was most marked at the medial tibial site. In addition, lateral tibial thickness was greater than medial tibial thickness (5.9 versus 3.6 mm; P < 0.0001) and lateral tibial volume was greater than medial tibial volume (2,823 versus 2,299 microl; P < 0.0001). Furthermore, physical activity was a significant explanatory factor for cartilage volume at all sites (R2 7-14% depending on site; all P < 0.05). The most consistent activity association was with vigorous activity in the previous 2 weeks (difference between any vigorous activity versus none 22-25% greater; all P < 0.05). CONCLUSION: Sex- and joint compartment-related differences in cartilage development may be one explanation for variations in the pattern of knee OA seen in later life. Furthermore, the physical activity associations suggest that cartilage development is amenable to modification.

The knee kinematics and kinetics of 139 patients (47 males and 92 females) with Grade II knee osteoarthritis (OA) were measured during level walking, stair ascent and stair descent. There was no significant difference in knee motion between the patients and normal subjects. The patients with knee OA had a significantly reduced internal knee extensor moment compared to normal subjects. This difference reflects the patient's compensation to reduce the knee joint loading. Further, subjects with OA and a higher body mass index have a lower knee extensor moment. The female subjects had significantly greater knee flexion and a greater knee extensor moment. This gender difference may partially explain the increased prevalence of OA in females. Most tests of OA treatments are assessed by criteria that do not reflect functional activities. This study demonstrates that objective gait analysis can be used to document gait adaptations used by patients with knee OA.

OBJECTIVE: Quadriceps sensorimotor dysfunction may be important in the pathogenesis of knee osteoarthritis (OA) and a determinant of disability. Exercise regimes can increase quadriceps strength, but whether this improves proprioception and reduces disability is uncertain. Moreover, research regimes involve protracted treatment which is clinically impracticable. METHODS: We compared quadriceps sensorimotor function and disability in 60 patients with knee OA, before and after an exercise regime, with a control group (n = 37) who did not exercise. RESULTS: Exercise improved quadriceps strength (mean change, 95% CI; 73 N, 26-19 N), voluntary activation (14%, 5-20%), knee joint position sense (0.6 degrees, 0.1-1.8 degrees), and reduced the Lequesne Index (3.5, 0.5-4) and aggregate time of four activities of daily living (8.4 s, 0.2-16.7 s). At 6 month follow-up, these improvements were maintained. The parameters of the control group were unchanged. CONCLUSIONS: These results substantiate the association between quadriceps sensorimotor dysfunction and disability, emphasizing the importance of quadriceps exercise in the management of knee OA. The regimen is relatively brief and clinically practicable, but could be adapted to make it more cost effective.

OBJECTIVE: This study tests the hypothesis that the peak external knee adduction moment during gait is increased in a group of ambulatory subjects with knee osteoarthritis (OA) of varying radiographic severity who are being managed with medical therapy. Tibiofemoral knee OA more commonly affects the medial compartment. The external knee adduction moment can be used to assess the load distribution between the medial and lateral compartments of the knee joint. Additionally, this study tests if changes in the knee angles, such as a reduced midstance knee flexion angle, or reduced sagittal plane moments previously identified by others as load reducing mechanisms are present in this OA group. DESIGN: Thirty-one subjects with radiographic evidence of knee OA and medial compartment cartilage damage were gait tested after a 2-week drug washout period. Thirty-one normal subjects (asymptomatic control subjects) with a comparable age, weight and height distribution were also tested. Significant differences in the sagittal plane knee motion and peak external moments between the normal and knee OA groups were identified using t tests. RESULTS: Subjects with knee OA walked with a greater than normal peak external knee adduction moment (P=0.003). The midstance knee flexion angle was not significantly different between the two groups (P=0.625) nor were the peak flexion and extension moments (P> 0.037). CONCLUSIONS: Load reducing mechanisms, such as a decreased midstance knee flexion angle, identified by others in subjects with endstage knee OA or reduced external flexion or extension moments were not present in this group of subjects with knee OA who were being managed by conservative treatment. The finding of a significantly greater than normal external knee adduction moment in the knee OA group lends support to the hypothesis that an increased knee adduction moment during gait is associated with knee OA.

OBJECTIVE: A clinical trial was conducted in 600 patients with OA of the knee to test the hypothesis that the specific COX-2 inhibitor, celecoxib, has equivalent efficacy and a superior tolerability/safety profile when compared to diclofenac, the current worldwide standard of care. METHODS: Patients were administered celecoxib 100 mg BID, diclofenac 50 mg TID or placebo for 6 weeks in a multicentre, double-blind. placebo-controlled trial. RESULTS: Primary efficacy measures (index joint pain by VAS, WOMAC index) indicated statistically significant improvement versus placebo for both celecoxib and diclofenac and no statistically significant differences between celecoxib and diclofenac. American Pain Society (APS) measures to assess the rapidity of onset of action showed statistically significant and comparable pain relief versus placebo within 24 h for both celecoxib and diclofenac. More diclofenac patients reported GI side effects than patients treated with either placebo or celecoxib. Diclofenac-treated patients experienced statistically significant elevations in mean hepatic transaminases and serum creatinine and reductions in haemoglobin concentration when compared to placebo, events not observed with celecoxib. CONCLUSION: Celecoxib 200 mg daily is as effective as diclofenac 150 mg daily for relieving signs and symptoms of OA of the knee, including pain, and has a rapid onset of action. However, celecoxib appears to have a superior safety and tolerability profile.

OBJECTIVES: Why some patients with knee osteoarthritis (OA) report greater pain severity than others is unclear. We examined the demographic variables, psychosocial variables, and physical findings that predict severity of pain in patients with symptomatic knee OA comparing 3 different pain scales. METHODS: Pain severity was measured in 68 outpatients with knee OA using the WOMAC OA Index, the McGill Pain Questionnaire (MPQ), and a 0-100 visual analog scale (VAS). Depression, anxiety, fatigue, helplessness, self-efficacy, and quality of life were measured using standard instruments. Pain threshold was measured by dolorimetry and a standard knee examination performed. Radiographs were viewed when available. RESULTS: Significant correlations (r = 0.39-0.61) were found between pain measures. In unadjusted analysis, BMI and helplessness correlated with all 3 scales; race, education, female sex, and osteophyte score also correlated with at least one instrument. Depression, anxiety, and fatigue correlated only with the MPQ. Age, duration, and quality of life were not related to pain severity. After adjusted analysis the following variables remained: education, helplessness, and osteophyte score (WOMAC); BMI and helplessness (MPQ); duration, education, helplessness, and osteophyte score (VAS)."Sitting pain" and "night pain" had different associations from pain on walking, standing, or using stairs. CONCLUSION: Different pain scales measure different facets of the pain experience in knee OA and cannot be used interchangeably. The WOMAC pain scale has advantages over other instruments. Helplessness, education, and BMI appear to be important, potentially treatable, factors in determining self-reported pain severity in knee OA: other associations vary with both the pain scale used and the situation in which pain occurs, supporting the hypothesis that pain in knee OA is heterogeneous.