- Email: [email protected]
Constant and intermittent knee pain and their relationship to physical activity: data from osteoarthritis initiative
Abstracts / Osteoarthritis and Cartilage 25 (2017) S76eS444
S371
Table 2 Factor Analysis Identified Novel Groups of Common Symptoms among Those at Risk for Accelerated Knee Osteoarthritis (AKOA) and Common Knee Osteoarthritis (KOA) AKOA (n ¼ 46 out of 54)
Difficulty: up stairs Difficulty: down stairs Difficulty: standing Difficulty: bending Difficulty: walking Difficulty: in car/out of car Difficulty: shopping Difficulty: socks on Difficulty: get out of bed Difficulty: socks off Difficulty: lying down Difficulty: sitting Difficulty: on/off toilet Difficulty: heavy chores Difficulty: light chores Pain: straightening knee fully Pain: bending knee fully Symptoms: swelling Symptoms: crepitus Symptoms: catching Symptoms: straightening Symptoms: bending Pain: walking Pain: up/down stairs Pain: in bed Pain: sit or lie down Pain: standing Eigen Value Variance explained by each factor
KOA (n ¼ 162 out of 187)
Factor1
Factor2
Factor3
Factor4
Factor5
Factor1
Factor2
Factor3
Factor4
0.86 0.86 0.48 0.68 0.38 0.72 0.36 0.20 0.66 0.28 0.10 0.18 0.75 0.36 0.28 0.44 0.42 0.20 0.32 0.01 0.05 0.14 0.37 0.71 0.26 0.18 0.66 13.44 6.02
0.17 0.08 0.66 0.33 0.60 0.25 0.40 0.18 0.10 0.02 0.21 0.79 0.12 0.47 0.43 0.32 0.33 0.07 0.07 0.05 0.09 0.01 0.42 0.26 0.14 0.51 0.29 2.05 3.14
0.07 0.12 0.14 0.22 0.43 0.20 0.21 0.12 0.39 0.09 0.86 0.41 0.28 0.08 0.29 0.35 0.23 0.35 0.14 0.00 0.04 0.08 0.11 0.01 0.83 0.66 0.23 1.77 3.14
0.23 0.11 0.11 0.19 0.34 0.38 0.46 0.88 0.42 0.82 0.13 0.12 0.05 0.13 0.16 0.29 0.18 0.24 0.01 0.03 0.21 0.24 0.37 0.15 0.12 0.02 0.09 1.53 2.74
0.00 0.08 0.14 0.19 0.08 0.06 0.13 0.19 0.14 0.32 0.01 0.01 0.17 0.15 0.01 0.14 0.05 0.01 0.23 0.17 0.79 0.81 0.05 0.06 0.13 0.06 0.13 1.34 1.74
0.31 0.16 0.69 0.44 0.73 0.17 0.45 0.25 0.27 0.24 0.19 0.22 0.25 0.44 0.50 0.44 0.63 0.30 0.02 0.01 0.05 0.21 0.62 0.42 0.26 0.27 0.66 12.76 4.22
0.68 0.73 0.41 0.66 0.30 0.61 0.50 0.25 0.40 0.25 0.22 0.49 0.53 0.56 0.44 0.22 0.23 0.11 0.07 0.18 0.08 0.16 0.13 0.43 0.26 0.11 0.13 1.47 4.17
0.25 0.21 0.21 0.16 0.20 0.23 0.33 0.86 0.52 0.87 0.29 0.19 0.38 0.36 0.36 0.27 0.28 0.09 0.01 0.02 0.09 0.10 0.14 0.20 0.10 0.19 0.15 1.12 2.97
0.15 0.22 0.17 0.21 0.17 0.21 0.23 0.17 0.20 0.17 0.74 0.25 0.10 0.11 0.12 0.27 0.16 0.26 0.03 0.07 0.09 0.01 0.26 0.18 0.80 0.56 0.16 1.09 2.26
604 CONSTANT AND INTERMITTENT RELATIONSHIP TO PHYSICAL OSTEOARTHRITIS INITIATIVE
KNEE PAIN AND ACTIVITY: DATA
THEIR FROM
J. Song y, A. Chang y, R. Chang y, J. Lee y, D. Pinto y, M. Nevitt z, D. Dunlop y. y Northwestern Univ., Chicago, IL, USA; z Univ. of California at San Francisco, San Francisco, CA, USA Purpose: To examine the relationship between knee pain and physical activity; and whether this relationship differs based on pain characteristics Methods: This cross-sectional study used data from 1894 participants with or at high risk for knee osteoarthritis who participated in the Osteoarthritis Initiative substudy at 48-month follow-up to objectively measure physical activity using accelerometers. Knee pain characteristics (constant and intermittent) during the previous week were scored by the Intermittent and Constant Osteoarthritis Pain (ICOAP) instrument (range 0 no pain - 100 extreme pain). Constant and intermittent knee pain were separately categorized into 3 pain levels: 1) no pain (pain score ¼ 0), 2) low pain (0 < pain score < median), and 3) moderate/high pain (pain score median). Median pain was calculated among people who reported pain: constant pain score median ¼ 35.0 for 207 participants with constant pain, and intermittent pain score median ¼ 20.8 among 1087 participants with intermittent pain. Physical activity was objectively measured in the following week using uniaxial accelerometer. Light and moderate intensity activity were identified on minute-by-minute base of activity counts 100e2019 and 2020 per minute, respectively. A graded “dose-response” relationships between average weekly minutes spent in moderate or light intensity activity and 3 pain levels were assessed by quantile regression adjusted for demographic (age and sex) and health factors (knee OA presence, body mass index, lower body pain, medicine for knee symptoms). Results: This cohort with or at high risk for knee OA had a mean age of 65 years; 55% were female; 61% had radiographic knee OA in at least one knee; and 35% were obese. Approximately 10% participants reported constant knee pain and about 60% participants reported intermittent knee pain in the past week. On average, this group spent 1929 minutes on light intensity and 80 minutes on moderate intensity physical
activity during the week. A strong negative graded relationship was found between greater constant knee pain and less time spent in moderate intensity physical activity (Table 1, p-value for trend ¼ 0.025), and a negative although statistically insignificant relationship with less time in light intensity activity (Table 1, p-value for trend ¼ 0.119). While greater intermittent knee pain tended to show a negative graded relationship with less moderate intensity physical activity, that trend was not statistically significant (Table 2, p-value for trend ¼ 0.235). No significant relationships were found between levels of intermittent knee pain and time spent in light intensity physical activity. Conclusions: Constant knee pain had a greater impact on moderate intensity than on light intensity physical activity. This relationship suggests that increasing light intensity physical activity could be an alternative initial pathway to better quality of life in people with knee pain.
Table 1 Adjusteda Medians (95% CI) of Physical Activity by Constant Knee Pain Levels (n ¼ 1894) Constant Knee Pain Levels
No Constant Pain (n ¼ 1687) Low Pain (n ¼ 102) Moderate/High Pain (n ¼ 105) P for trend a
Difference (95% Confidence Interval) in Physical Activity Medians Compared to No Constant Pain; % Difference from No Constant Pain Moderate Intensity Activity (minutes/week)
Light Intensity Activity (minutes/week)
Reference
Reference
4 (29, 21); 7.0%* 37 (63, 10); 64.9% *
27 (142, 88); 1.4% ** 89 (208, 32); 4.6% **
0.025
0.119
Adjusted for age, gender, OA presence, obesity, lower body pain, medication for knee symptoms, and intermittent ICOAP knee pain score. * In relation to reference group median of 57 minutes/week moderate intensity activity. ** In relation to reference group median of 1923 minutes/week light intensity activity.
S372
Abstracts / Osteoarthritis and Cartilage 25 (2017) S76eS444
Table 2 Adjusteda Medians (95% CI) of Physical Activity by Intermittent Knee Pain Levels (n ¼ 1894) Intermittent Knee Pain Levels
No Pain (n ¼ 807) Low Pain (n ¼ 558) Moderate/High Pain (n ¼ 529) P for trend
Difference (95% Confidence Interval) in Physical Activity Medians Compared to No Intermittent Pain; % Difference from No Intermittent Pain
J. Westra y, z, E.L. Ashbeck y, A. Guermazi x, F. Roemer x, k, C.K. Kwoh y, ¶. y Univ. of Arizona Arthritis Ctr., Tucson, AZ, USA; z Dept. of Epidemiology and Biostatistics, Univ. of Arizona, Tucson, AZ, USA; x Boston Univ. Sch. of Med., Boston, MA, USA; k Dept. of Radiology, Univ. of ErlangenNuremberg, Erlangen, Germany; ¶ Dept. of Med., Div. of Rheumatology, The Univ. of Arizona, Tucson, AZ, USA
Moderate Intensity Activity (minutes/week)
Light Intensity Activity (minutes/week)
Reference 0 (13, 14); 0.0% * 10 (24, 4); 17.5% *
Reference 15 (78, 47); 1.0% ** 13 (79, 52); 1.0% **
0.235
0.595
a
Adjusted for age, gender, OA presence, obesity, lower body pain, medication for knee symptoms, and constant ICOAP knee pain score. * In relation to reference group median of 57 minutes/week moderate intensity activity. ** In relation to reference group median of 1925 minutes/week light intensity activity.
605 PREOPERATIVE PAIN SENSITIZATION REPLACEMENT OUTCOME
AND
TOTAL
606 BURDEN OF MRI-DETECTED PATHOLOGICAL FEATURES AND FUTURE TRAJECTORIES OF PAIN AND FUNCTION IN PARTICIPANTS WITH RADIOGRAPHIC KNEE OSTEOARTHRITIS
KNEE
Y.Y. Leung y, z, B. Chakraborty x, Z. Lim k, S. Yeo ¶, N. Lo ¶, M. Tan ¶, S. Wong #, H. Chong ¶, W. Yeo ¶, V. Wylde yy, P. Dieppe zz, J. Thumboo y, z. y Dept. of Rheumatology & Immunology, Singapore Gen. Hosp., Singapore, Singapore; z Duke-NUS Med. Sch., Singapore, Singapore; x Ctr. for Quantitative Med., Duke-NUS Med. Sch., Singapore, Singapore; k Yoo Long Lin Sch. of Med., Natl. Univ. of Singapore, Singapore, Singapore; ¶ Dept. of Orthopedic Surgery, Singapore Gen. Hosp., Singapore, Singapore; # Dept. of Diagnostic Radiology, Singapore Gen. Hosp., Singapore, Singapore; yy Musculoskeletal Res. Unit, Sch. of Clinical Sci., Univ. of Bristol, United Kingdom, United Kingdom; zz Univ. of Exeter, United Kingdom, United Kingdom Purpose: Approximately 20% of patients do not have a good outcome after knee replacement surgery (KR) for knee osteoarthritis (KOA). Pain sensitization could be a potential risk factor for poor KR outcomes. We aimed to evaluate the association between pre-operative pain sensitization and KR outcomes. Methods: Consecutive patients with severe KOA enlisted for KR were recruited at a tertiary orthopaedic centre. Pre-operative pressure pain thresholds at the knee (PPT-knee) and forearm (PPT-forearm) were measured using a digital pressure algometer. Data on sociodemographics was collected pre-operatively and patients completed the WOMAC questionnaire pre-operatively and at 6 months post-operative. Satisfaction was assessed 6 months after KR using a 4-point likert scale. Non-responders were defined as those reporting “somewhat dissatisfied” and “very dissatisfied” with KR. Results: Out of 243 patients recruited, 232 patients completed a questionnaire at 6 months post-operative (response rate 95.5%). The mean (SD) age of participants was 66.1(8.3) and 78.4% were women. The non-responder rate to KR was 8.6%. Non-responders had significant lower pre-operative PPT-knee (188.1 kPa vs 150.9 kPa, p ¼ 0.040); and lower PPT-forearm (186.1 kPa vs 156.9 kPa, p ¼ 0.059) but not reaching significance. Non-responders had significant worse pre-operative and 6 month post-operative WOMAC scores. Pre-operative PPT-knee was negatively associated with WOMAC movement pain, WOMAC function, and patient dissatisfaction at 6 months, which remained significant after adjustment with age, sex, body mass index, but became insignificant with further adjustment for pre-operative WOMAC. PPTs were not associated with change in WOMAC scores. Conclusions: PPTs as measured by digital pressure algometer do not predict degree of improvement and satisfaction to KR.
Purpose: Knee pain and reduced function are common symptoms in patients with knee osteoarthritis (OA), but the relationship between MRI-detected pathological features of OA and change in pain and disability are poorly understood. The objective was to examine the relationship between structural features detected on MRI the year prior to incident radiographic OA (ROA), and pain and disability crosssectionally and longitudinally up to 3 years following MRI assessment. Methods: The Osteoarthritis Initiative (OAI) is a longitudinal cohort study of participants with or at risk of knee OA. A sample of 330 knees (contributed by 303 participants) with MRI readings available the year prior to evidence of incident ROA (i.e., KL 2) during 48 months followup was identified. Structural features included effusion-synovitis, Hoffa-synovitis, cartilage damage, bone marrow lesions (BML), and meniscal pathology, including tears, macerations and extrusions, ascertained from 3T MRI and scored using the MRI Osteoarthritis Knee Score (MOAKS) instrument. Burden of structural damage was calculated by counting the number of MRI-detected pathological features present (0e5). Pain and disability were assessed annually from one year prior to three years following MRI assessment, using Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee pain (0e20) and disability (0e68) in the past 7 days. Mixed models with random effects were used to estimate mean pain and disability levels at each visit, with adjustment for age and sex. Results: The 303 participants were mostly female (65%), overweight (43%) or obese (39%), white (81%), and with mean age of 62. Effusionsynovitis was medium/large in 49 knees, small in 145 knees, with 136 knees exhibiting no effusion. Knees with a medium/large amount of effusion-synovitis had higher WOMAC knee pain scores than knees with none the year of MRI assessment (mean difference: 2.5; 95% CI: 1.6e3.4) and one year later (mean difference: 1.2; 95% CI: 0.3e2.2), though the difference attenuated over the three years following MRI detection of effusion-synovitis [Figure 1A]. Knees with medium/large effusion-synovitis also had higher WOMAC disability than knees with none the year of MRI assessment (mean difference: 7.5; 95% CI: 4.4e10.5) and also the following year (mean difference: 6.0; 95% CI: 3.0e9.0), but the effect similarly attenuated over the three years following MRI detection of effusion-synovitis [Figure 1B]. When examined individually, Hoffa-synovitis, cartilage damage, BMLs, and meniscal pathology did not show strong evidence of distinguishing pain and disability levels (data not shown). With regard to structural damage burden, there were 9 knees (3%) with 0 MRI-detected features present, 33 (10%) with one, 73 (22%) with two, 97 (29%) with three, 82 (25%) with four, and 36 (11%) with five features. Knees with five MRI-detected features present had consistently higher levels of WOMAC knee pain and WOMAC disability up to three years following MRI assessment [Figure 1C]. Conclusions: MRI-detected effusion-synovitis was associated with knee pain and disability, but this effect attenuated longitudinally over three years, consistent with the transient nature of effusion-synovitis. Other MRI-detected features did not capture remarkable contrasts in pain and disability levels when examined individually. Burden of damage captured by a simple count of the number of the MRI-detected pathological features present demonstrated the greatest differences in pain and disability levels and these differences persisted over the following three years.
S371
Table 2 Factor Analysis Identified Novel Groups of Common Symptoms among Those at Risk for Accelerated Knee Osteoarthritis (AKOA) and Common Knee Osteoarthritis (KOA) AKOA (n ¼ 46 out of 54)
Difficulty: up stairs Difficulty: down stairs Difficulty: standing Difficulty: bending Difficulty: walking Difficulty: in car/out of car Difficulty: shopping Difficulty: socks on Difficulty: get out of bed Difficulty: socks off Difficulty: lying down Difficulty: sitting Difficulty: on/off toilet Difficulty: heavy chores Difficulty: light chores Pain: straightening knee fully Pain: bending knee fully Symptoms: swelling Symptoms: crepitus Symptoms: catching Symptoms: straightening Symptoms: bending Pain: walking Pain: up/down stairs Pain: in bed Pain: sit or lie down Pain: standing Eigen Value Variance explained by each factor
KOA (n ¼ 162 out of 187)
Factor1
Factor2
Factor3
Factor4
Factor5
Factor1
Factor2
Factor3
Factor4
0.86 0.86 0.48 0.68 0.38 0.72 0.36 0.20 0.66 0.28 0.10 0.18 0.75 0.36 0.28 0.44 0.42 0.20 0.32 0.01 0.05 0.14 0.37 0.71 0.26 0.18 0.66 13.44 6.02
0.17 0.08 0.66 0.33 0.60 0.25 0.40 0.18 0.10 0.02 0.21 0.79 0.12 0.47 0.43 0.32 0.33 0.07 0.07 0.05 0.09 0.01 0.42 0.26 0.14 0.51 0.29 2.05 3.14
0.07 0.12 0.14 0.22 0.43 0.20 0.21 0.12 0.39 0.09 0.86 0.41 0.28 0.08 0.29 0.35 0.23 0.35 0.14 0.00 0.04 0.08 0.11 0.01 0.83 0.66 0.23 1.77 3.14
0.23 0.11 0.11 0.19 0.34 0.38 0.46 0.88 0.42 0.82 0.13 0.12 0.05 0.13 0.16 0.29 0.18 0.24 0.01 0.03 0.21 0.24 0.37 0.15 0.12 0.02 0.09 1.53 2.74
0.00 0.08 0.14 0.19 0.08 0.06 0.13 0.19 0.14 0.32 0.01 0.01 0.17 0.15 0.01 0.14 0.05 0.01 0.23 0.17 0.79 0.81 0.05 0.06 0.13 0.06 0.13 1.34 1.74
0.31 0.16 0.69 0.44 0.73 0.17 0.45 0.25 0.27 0.24 0.19 0.22 0.25 0.44 0.50 0.44 0.63 0.30 0.02 0.01 0.05 0.21 0.62 0.42 0.26 0.27 0.66 12.76 4.22
0.68 0.73 0.41 0.66 0.30 0.61 0.50 0.25 0.40 0.25 0.22 0.49 0.53 0.56 0.44 0.22 0.23 0.11 0.07 0.18 0.08 0.16 0.13 0.43 0.26 0.11 0.13 1.47 4.17
0.25 0.21 0.21 0.16 0.20 0.23 0.33 0.86 0.52 0.87 0.29 0.19 0.38 0.36 0.36 0.27 0.28 0.09 0.01 0.02 0.09 0.10 0.14 0.20 0.10 0.19 0.15 1.12 2.97
0.15 0.22 0.17 0.21 0.17 0.21 0.23 0.17 0.20 0.17 0.74 0.25 0.10 0.11 0.12 0.27 0.16 0.26 0.03 0.07 0.09 0.01 0.26 0.18 0.80 0.56 0.16 1.09 2.26
604 CONSTANT AND INTERMITTENT RELATIONSHIP TO PHYSICAL OSTEOARTHRITIS INITIATIVE
KNEE PAIN AND ACTIVITY: DATA
THEIR FROM
J. Song y, A. Chang y, R. Chang y, J. Lee y, D. Pinto y, M. Nevitt z, D. Dunlop y. y Northwestern Univ., Chicago, IL, USA; z Univ. of California at San Francisco, San Francisco, CA, USA Purpose: To examine the relationship between knee pain and physical activity; and whether this relationship differs based on pain characteristics Methods: This cross-sectional study used data from 1894 participants with or at high risk for knee osteoarthritis who participated in the Osteoarthritis Initiative substudy at 48-month follow-up to objectively measure physical activity using accelerometers. Knee pain characteristics (constant and intermittent) during the previous week were scored by the Intermittent and Constant Osteoarthritis Pain (ICOAP) instrument (range 0 no pain - 100 extreme pain). Constant and intermittent knee pain were separately categorized into 3 pain levels: 1) no pain (pain score ¼ 0), 2) low pain (0 < pain score < median), and 3) moderate/high pain (pain score median). Median pain was calculated among people who reported pain: constant pain score median ¼ 35.0 for 207 participants with constant pain, and intermittent pain score median ¼ 20.8 among 1087 participants with intermittent pain. Physical activity was objectively measured in the following week using uniaxial accelerometer. Light and moderate intensity activity were identified on minute-by-minute base of activity counts 100e2019 and 2020 per minute, respectively. A graded “dose-response” relationships between average weekly minutes spent in moderate or light intensity activity and 3 pain levels were assessed by quantile regression adjusted for demographic (age and sex) and health factors (knee OA presence, body mass index, lower body pain, medicine for knee symptoms). Results: This cohort with or at high risk for knee OA had a mean age of 65 years; 55% were female; 61% had radiographic knee OA in at least one knee; and 35% were obese. Approximately 10% participants reported constant knee pain and about 60% participants reported intermittent knee pain in the past week. On average, this group spent 1929 minutes on light intensity and 80 minutes on moderate intensity physical
activity during the week. A strong negative graded relationship was found between greater constant knee pain and less time spent in moderate intensity physical activity (Table 1, p-value for trend ¼ 0.025), and a negative although statistically insignificant relationship with less time in light intensity activity (Table 1, p-value for trend ¼ 0.119). While greater intermittent knee pain tended to show a negative graded relationship with less moderate intensity physical activity, that trend was not statistically significant (Table 2, p-value for trend ¼ 0.235). No significant relationships were found between levels of intermittent knee pain and time spent in light intensity physical activity. Conclusions: Constant knee pain had a greater impact on moderate intensity than on light intensity physical activity. This relationship suggests that increasing light intensity physical activity could be an alternative initial pathway to better quality of life in people with knee pain.
Table 1 Adjusteda Medians (95% CI) of Physical Activity by Constant Knee Pain Levels (n ¼ 1894) Constant Knee Pain Levels
No Constant Pain (n ¼ 1687) Low Pain (n ¼ 102) Moderate/High Pain (n ¼ 105) P for trend a
Difference (95% Confidence Interval) in Physical Activity Medians Compared to No Constant Pain; % Difference from No Constant Pain Moderate Intensity Activity (minutes/week)
Light Intensity Activity (minutes/week)
Reference
Reference
4 (29, 21); 7.0%* 37 (63, 10); 64.9% *
27 (142, 88); 1.4% ** 89 (208, 32); 4.6% **
0.025
0.119
Adjusted for age, gender, OA presence, obesity, lower body pain, medication for knee symptoms, and intermittent ICOAP knee pain score. * In relation to reference group median of 57 minutes/week moderate intensity activity. ** In relation to reference group median of 1923 minutes/week light intensity activity.
S372
Abstracts / Osteoarthritis and Cartilage 25 (2017) S76eS444
Table 2 Adjusteda Medians (95% CI) of Physical Activity by Intermittent Knee Pain Levels (n ¼ 1894) Intermittent Knee Pain Levels
No Pain (n ¼ 807) Low Pain (n ¼ 558) Moderate/High Pain (n ¼ 529) P for trend
Difference (95% Confidence Interval) in Physical Activity Medians Compared to No Intermittent Pain; % Difference from No Intermittent Pain
J. Westra y, z, E.L. Ashbeck y, A. Guermazi x, F. Roemer x, k, C.K. Kwoh y, ¶. y Univ. of Arizona Arthritis Ctr., Tucson, AZ, USA; z Dept. of Epidemiology and Biostatistics, Univ. of Arizona, Tucson, AZ, USA; x Boston Univ. Sch. of Med., Boston, MA, USA; k Dept. of Radiology, Univ. of ErlangenNuremberg, Erlangen, Germany; ¶ Dept. of Med., Div. of Rheumatology, The Univ. of Arizona, Tucson, AZ, USA
Moderate Intensity Activity (minutes/week)
Light Intensity Activity (minutes/week)
Reference 0 (13, 14); 0.0% * 10 (24, 4); 17.5% *
Reference 15 (78, 47); 1.0% ** 13 (79, 52); 1.0% **
0.235
0.595
a
Adjusted for age, gender, OA presence, obesity, lower body pain, medication for knee symptoms, and constant ICOAP knee pain score. * In relation to reference group median of 57 minutes/week moderate intensity activity. ** In relation to reference group median of 1925 minutes/week light intensity activity.
605 PREOPERATIVE PAIN SENSITIZATION REPLACEMENT OUTCOME
AND
TOTAL
606 BURDEN OF MRI-DETECTED PATHOLOGICAL FEATURES AND FUTURE TRAJECTORIES OF PAIN AND FUNCTION IN PARTICIPANTS WITH RADIOGRAPHIC KNEE OSTEOARTHRITIS
KNEE
Y.Y. Leung y, z, B. Chakraborty x, Z. Lim k, S. Yeo ¶, N. Lo ¶, M. Tan ¶, S. Wong #, H. Chong ¶, W. Yeo ¶, V. Wylde yy, P. Dieppe zz, J. Thumboo y, z. y Dept. of Rheumatology & Immunology, Singapore Gen. Hosp., Singapore, Singapore; z Duke-NUS Med. Sch., Singapore, Singapore; x Ctr. for Quantitative Med., Duke-NUS Med. Sch., Singapore, Singapore; k Yoo Long Lin Sch. of Med., Natl. Univ. of Singapore, Singapore, Singapore; ¶ Dept. of Orthopedic Surgery, Singapore Gen. Hosp., Singapore, Singapore; # Dept. of Diagnostic Radiology, Singapore Gen. Hosp., Singapore, Singapore; yy Musculoskeletal Res. Unit, Sch. of Clinical Sci., Univ. of Bristol, United Kingdom, United Kingdom; zz Univ. of Exeter, United Kingdom, United Kingdom Purpose: Approximately 20% of patients do not have a good outcome after knee replacement surgery (KR) for knee osteoarthritis (KOA). Pain sensitization could be a potential risk factor for poor KR outcomes. We aimed to evaluate the association between pre-operative pain sensitization and KR outcomes. Methods: Consecutive patients with severe KOA enlisted for KR were recruited at a tertiary orthopaedic centre. Pre-operative pressure pain thresholds at the knee (PPT-knee) and forearm (PPT-forearm) were measured using a digital pressure algometer. Data on sociodemographics was collected pre-operatively and patients completed the WOMAC questionnaire pre-operatively and at 6 months post-operative. Satisfaction was assessed 6 months after KR using a 4-point likert scale. Non-responders were defined as those reporting “somewhat dissatisfied” and “very dissatisfied” with KR. Results: Out of 243 patients recruited, 232 patients completed a questionnaire at 6 months post-operative (response rate 95.5%). The mean (SD) age of participants was 66.1(8.3) and 78.4% were women. The non-responder rate to KR was 8.6%. Non-responders had significant lower pre-operative PPT-knee (188.1 kPa vs 150.9 kPa, p ¼ 0.040); and lower PPT-forearm (186.1 kPa vs 156.9 kPa, p ¼ 0.059) but not reaching significance. Non-responders had significant worse pre-operative and 6 month post-operative WOMAC scores. Pre-operative PPT-knee was negatively associated with WOMAC movement pain, WOMAC function, and patient dissatisfaction at 6 months, which remained significant after adjustment with age, sex, body mass index, but became insignificant with further adjustment for pre-operative WOMAC. PPTs were not associated with change in WOMAC scores. Conclusions: PPTs as measured by digital pressure algometer do not predict degree of improvement and satisfaction to KR.
Purpose: Knee pain and reduced function are common symptoms in patients with knee osteoarthritis (OA), but the relationship between MRI-detected pathological features of OA and change in pain and disability are poorly understood. The objective was to examine the relationship between structural features detected on MRI the year prior to incident radiographic OA (ROA), and pain and disability crosssectionally and longitudinally up to 3 years following MRI assessment. Methods: The Osteoarthritis Initiative (OAI) is a longitudinal cohort study of participants with or at risk of knee OA. A sample of 330 knees (contributed by 303 participants) with MRI readings available the year prior to evidence of incident ROA (i.e., KL 2) during 48 months followup was identified. Structural features included effusion-synovitis, Hoffa-synovitis, cartilage damage, bone marrow lesions (BML), and meniscal pathology, including tears, macerations and extrusions, ascertained from 3T MRI and scored using the MRI Osteoarthritis Knee Score (MOAKS) instrument. Burden of structural damage was calculated by counting the number of MRI-detected pathological features present (0e5). Pain and disability were assessed annually from one year prior to three years following MRI assessment, using Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee pain (0e20) and disability (0e68) in the past 7 days. Mixed models with random effects were used to estimate mean pain and disability levels at each visit, with adjustment for age and sex. Results: The 303 participants were mostly female (65%), overweight (43%) or obese (39%), white (81%), and with mean age of 62. Effusionsynovitis was medium/large in 49 knees, small in 145 knees, with 136 knees exhibiting no effusion. Knees with a medium/large amount of effusion-synovitis had higher WOMAC knee pain scores than knees with none the year of MRI assessment (mean difference: 2.5; 95% CI: 1.6e3.4) and one year later (mean difference: 1.2; 95% CI: 0.3e2.2), though the difference attenuated over the three years following MRI detection of effusion-synovitis [Figure 1A]. Knees with medium/large effusion-synovitis also had higher WOMAC disability than knees with none the year of MRI assessment (mean difference: 7.5; 95% CI: 4.4e10.5) and also the following year (mean difference: 6.0; 95% CI: 3.0e9.0), but the effect similarly attenuated over the three years following MRI detection of effusion-synovitis [Figure 1B]. When examined individually, Hoffa-synovitis, cartilage damage, BMLs, and meniscal pathology did not show strong evidence of distinguishing pain and disability levels (data not shown). With regard to structural damage burden, there were 9 knees (3%) with 0 MRI-detected features present, 33 (10%) with one, 73 (22%) with two, 97 (29%) with three, 82 (25%) with four, and 36 (11%) with five features. Knees with five MRI-detected features present had consistently higher levels of WOMAC knee pain and WOMAC disability up to three years following MRI assessment [Figure 1C]. Conclusions: MRI-detected effusion-synovitis was associated with knee pain and disability, but this effect attenuated longitudinally over three years, consistent with the transient nature of effusion-synovitis. Other MRI-detected features did not capture remarkable contrasts in pain and disability levels when examined individually. Burden of damage captured by a simple count of the number of the MRI-detected pathological features present demonstrated the greatest differences in pain and disability levels and these differences persisted over the following three years.