Optimization of Analgesics for Greater Exercise Therapy Participation Among Patients With Knee Osteoarthritis and Severe Pain: A Feasibility Study.

OBJECTIVE: Severe pain in patients with knee osteoarthritis (OA) hampers the ability to exercise. A protocol for the standardized optimization of analgesics in combination with exercise therapy was developed. The purpose of this protocol was to reduce pain, thereby allowing the patient to participate in exercise therapy. The objective of the present study was to evaluate the feasibility and outcome of the protocol. METHODS: Forty-nine patients with knee OA and severe knee pain (numerical rating scale for pain ≥7) were included. Analgesics were prescribed following an incremental protocol. After 6 weeks, a 12-week exercise therapy program was added. Information about analgesic use and exercise therapy content was recorded. Knee pain and activity limitations were assessed at baseline, after 6 weeks, and after 18 weeks. RESULTS: Statistically significant improvements in pain and activity limitations were found in intent-to-treat analysis after 6 weeks of analgesic use and after the intervention was completed. Mean improvements from baseline were 30% (P < 0.001) for pain and 17% (P < 0.001) for activity limitations after the intervention was completed. Seventy-eight percent of the patients were able to exercise according to the protocol. In these patients, exercise therapy following 6 weeks of analgesic use resulted in a further improvement of activity limitations of 10% (P = 0.004). CONCLUSION: The combined intervention of standardized analgesic prescription and exercise therapy allows most patients with knee OA and severe pain to participate in exercise therapy, leading to reduction of pain and activity limitations. These promising results need to be confirmed in a randomized controlled trial.

The association of body-mass index and depressed mood with knee pain and activity limitations in knee osteoarthritis: results from the Amsterdam osteoarthritis cohort.

BACKGROUND: Body-mass index (BMI) and depressed mood are both positively associated with pain and activity limitations in knee osteoarthritis (OA), and are interrelated. The aims of the present study were: 1) to assess whether BMI and depressed mood are independently associated with knee pain and activity limitations; and 2) to compare the relative contributions of BMI and depressed mood to knee pain and activity limitations. METHODS: A cross-sectional study in 294 patients with clinical knee OA. Regression analyses were performed with knee pain or activity limitations (self-reported and performance-based) as dependent variables, and BMI and depressed mood as independent variables. All analyses were adjusted for age, gender, marital status, education level, radiographic OA and comorbidity. Dominance analyses were performed to examine the relative contributions of BMI and depressed mood to knee pain and activity limitations. RESULTS: BMI and depressed mood were positively and independently associated with knee pain and activity limitations. BMI and depressed mood explained small parts (3.0% and 2.3%, respectively) of variance in knee pain. BMI explained a substantial part of variance in both self-reported (9.8%) and performance-based (20.4%) activity limitations, while depressed mood explained a small part of variance (3.1% in self-reported and 2.6% in performance-based activity limitations). CONCLUSIONS: In patients with knee OA both BMI and depressed mood seem to be independently associated with knee pain and activity limitations. The contribution of BMI to activity limitations is most substantial, thereby offering a relevant target for interventions.

Biomechanical factors and physical examination findings in osteoarthritis of the knee: associations with tissue abnormalities assessed by conventional radiography and high-resolution 3.0 Tesla magnetic resonance imaging.

INTRODUCTION: We aimed to explore the associations between knee osteoarthritis (OA)-related tissue abnormalities assessed by conventional radiography (CR) and by high-resolution 3.0 Tesla magnetic resonance imaging (MRI), as well as biomechanical factors and findings from physical examination in patients with knee OA. METHODS: This was an explorative cross-sectional study of 105 patients with knee OA. Index knees were imaged using CR and MRI. Multiple features from CR and MRI (cartilage, osteophytes, bone marrow lesions, effusion and synovitis) were related to biomechanical factors (quadriceps and hamstrings muscle strength, proprioceptive accuracy and varus-valgus laxity) and physical examination findings (bony tenderness, crepitus, bony enlargement and palpable warmth), using multivariable regression analyses. RESULTS: Quadriceps weakness was associated with cartilage integrity, effusion, synovitis (all detected by MRI) and CR-detected joint space narrowing. Knee joint laxity was associated with MRI-detected cartilage integrity, CR-detected joint space narrowing and osteophyte formation. Multiple tissue abnormalities including cartilage integrity, osteophytes and effusion, but only those detected by MRI, were found to be associated with physical examination findings such as crepitus. CONCLUSION: We observed clinically relevant findings, including a significant association between quadriceps weakness and both effusion and synovitis, detected by MRI. Inflammation was detected in over one-third of the participants, emphasizing the inflammatory component of OA and a possible important role for anti-inflammatory therapies in knee OA. In general, OA-related tissue abnormalities of the knee, even those detected by MRI, were found to be discordant with biomechanical and physical examination features.

Proprioception, laxity, muscle strength and activity limitations in early symptomatic knee osteoarthritis: results from the CHECK cohort.

OBJECTIVE: To establish whether proprioception and varus-valgus laxity moderate the association between muscle strength and activity limitations in patients with early symptomatic knee osteoarthritis. DESIGN: A cross-sectional study. SUBJECTS: A sample of 151 participants with early symptomatic knee osteoarthritis from the Cohort Hip and Cohort Knee study. METHODS: Regression analyses were performed to establish the associations between muscle strength, proprioception (knee joint motion detection threshold in the anterior--posterior direction), varus-valgus laxity and activity limitations (self-reported and performance-based). Interaction terms were used to establish whether proprioception and laxity moderated the association between muscle strength and activity limitations. RESULTS: Proprioception moderated the association between muscle strength and activity limitations: the negative association between muscle strength and activity limitations was stronger in participants with poor proprioception than in participants with accurate proprioception (performance-based activity limitations p = 0.02; self-reported activity limitations p = 0.08). The interaction between muscle strength and varus-valgus laxity was not significantly associated with activity limitations. CONCLUSION: The results of the present study support the theory that in the absence of adequate proprioceptive input, lower muscle strength affects a patient's level of activities to a greater degree than in the presence of adequate proprioceptive input.

Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: results from the Amsterdam Osteoarthritis cohort.

OBJECTIVE: To determine whether muscle strength, proprioceptive accuracy, and laxity are associated with self-reported knee instability in a large cohort of knee osteoarthritis (OA) patients, and to investigate whether muscle strength may compensate for impairment in proprioceptive accuracy or laxity, in order to maintain knee stability. METHODS: Data from 283 knee OA patients from the Amsterdam Osteoarthritis cohort were used. Univariable and multivariable logistic regression analyses were performed to assess the association between muscle strength, proprioceptive accuracy (motion sense), frontal plane varus-valgus laxity, and self-reported knee instability. Additionally, effect modification between muscle strength and proprioceptive accuracy and between muscle strength and laxity was determined. RESULTS: Self-reported knee instability was present in 67% of the knee OA patients and mainly occurred during walking. Lower muscle strength was significantly associated with the presence of self-reported knee instability, even after adjusting for relevant confounding. Impaired proprioceptive accuracy and high laxity were not associated with self-reported knee instability. No effect modification between muscle strength and proprioceptive accuracy or laxity was found. CONCLUSION: Lower muscle strength is strongly associated with self-reported knee instability in knee OA patients, while impairments in proprioceptive accuracy and laxity are not. A compensatory role of muscle strength for impaired proprioceptive accuracy or high laxity, in order to stabilize the knee, could not be demonstrated.