Carina A Thorstensson

Reduced functional performance in the lower extremity predicted radiographic knee osteoarthritis five years later

Background: Reduced quadriceps strength is an early finding in subjects with knee osteoarthritis, but it is not clear whether it is a cause or a consequence of knee osteoarthritis. Objective: To determine whether reduced functional performance in the lower extremity predicts the incidence or progression of radiographic knee osteoarthritis. Design: Prospective, epidemiological, population based cohort study. Patients: 148 subjects (62 women), aged 35–54 (mean 44.8), with chronic knee pain from a population based cohort. Measurements: Predictors analysed were age, sex, body mass index, baseline knee pain, and three tests of lower extremity functional performance: maximum number of one-leg rises from sitting, time spent walking 300 m, and timed standing on one leg. Weightbearing tibiofemoral knee radiographs were obtained at baseline and after 5 years (median 5.1, range 4.2–6.1), and classified according to Kellgren and Lawrence as no osteoarthritis (Kellgren and Lawrence = 0, n = 94) or prevalent osteoarthritis (Kellgren and Lawrence ⩾1, n = 54). Results: Fewer one-leg rises (median 17 v 25) predicted incident radiographic osteoarthritis five years later (OR 2.6, 95% CI 1.1 to 6.0). The association remained significant after controlling for age, sex, body mass index, and pain. No significant predictor of radiographic progression in the group with prevalent osteoarthritis was found. Conclusion: Reduced functional performance in the lower extremity predicted development of radiographic knee osteoarthritis 5 years later among people aged 35–55 with chronic knee pain and normal radiographs at baseline. These findings suggest that a test of one-leg rises may be useful, and interventions aimed at improving functional performance may be protective against development of knee osteoarthritis.

Proprioception in knee osteoarthritis: a narrative review

OBJECTIVE To give an overview of the literature on knee proprioception in knee osteoarthritis (OA) patients. METHOD A literature search was performed and reviewed using the narrative approach. RESULTS (1) Three presumed functions of knee proprioception have been described in the literature: protection against excessive movements, stabilization during static postures, and coordination of movements. (2) Proprioceptive accuracy can be measured in different ways; correlations between these methods are low. (3) Proprioceptive accuracy in knee OA patients seems to be impaired when compared to age-matched healthy controls. Unilateral knee OA patients may have impaired proprioceptive accuracy in both knees. (4) Causes of impaired proprioceptive accuracy in knee OA remain unknown. (5) There is currently no evidence for a role of impaired proprioceptive accuracy in the onset or progression of radiographic osteoarthritis (ROA). (6) Impaired proprioceptive accuracy could be a risk factor for progression (but not for onset) of both knee pain and activity limitations in knee OA patients. (7) Exercise therapy seems to be effective in improving proprioceptive accuracy in knee OA patients. CONCLUSIONS Recent literature has shown that proprioceptive accuracy may play an important role in knee OA. However, this role needs to be further clarified. A new measurement protocol for knee proprioception needs to be developed. Systematic reviews focusing on the relationship between impaired proprioceptive accuracy, knee pain and activity limitations and on the effect of interventions (in particular exercise therapy) on proprioceptive accuracy in knee OA are required. Future studies focusing on causes of impaired proprioceptive accuracy in knee OA patients are also needed, taking into account that also the non-symptomatic knee may have proprioceptive impairments. Such future studies may also provide knowledge of mechanism underlying the impact of impaired proprioceptive accuracy on knee pain and activity limitations.

Six-week high-intensity exercise program for middle-aged patients with knee osteoarthritis: a randomized controlled trial [ISRCTN20244858]

BackgroundStudies on exercise in knee osteoarthritis (OA) have focused on elderly subjects. Subjects in this study were middle-aged with symptomatic and definite radiographic knee osteoarthritis. The aim was to test the effects of a short-term, high-intensity exercise program on self-reported pain, function and quality of life.MethodsPatients aged 36–65, with OA grade III (Kellgren & Lawrence) were recruited. They had been referred for radiographic examination due to knee pain and had no history of major knee injury. They were randomized to a twice weekly supervised one hour exercise intervention for six weeks, or to a non-intervention control group. Exercise was performed at ≥ 60% of maximum heart rate (HR max). The primary outcome measure was the Knee injury and Osteoarthritis Outcome Score (KOOS). Follow-up occurred at 6 weeks and 6 months.ResultsSixty-one subjects (mean age 56 (SD 6), 51 % women, mean BMI 29.5 (SD 4.8)) were randomly assigned to intervention (n = 30) or control group (n = 31). No significant differences in the KOOS subscales assessing pain, other symptoms, or function in daily life or in sport and recreation were seen at any time point between exercisers and controls. In the exercise group, an improvement was seen at 6 weeks in the KOOS subscale quality of life compared to the control group (mean change 4.0 vs. -0.7, p = 0.05). The difference between groups was still persistent at 6 months (p = 0.02).ConclusionA six-week high-intensive exercise program had no effect on pain or function in middle-aged patients with moderate to severe radiographic knee OA. Some effect was seen on quality of life in the exercise group compared to the control group.

Serum levels of Cartilage Oligomeric Matrix Protein (COMP) increase temporarily after physical exercise in patients with knee osteoarthritis

BackgroundCOMP (Cartilage oligomeric matrix protein) is a matrix protein, which is currently studied as a potential serum marker for cartilage processes in osteoarthritis (OA). The influence of physical exercise on serum COMP is not fully elucidated.The objective of the present study was to monitor serum levels of COMP during a randomised controlled trial of physical exercise vs. standardised rest in individuals with symptomatic and radiographic knee OA.MethodsBlood samples were collected from 58 individuals at predefined time points before and after exercise or rest, one training group and one control group. The physical exercise consisted of a one-hour supervised session twice a week and daily home exercises. In a second supplementary study 7 individuals were subjected to the same exercise program and sampling of blood was performed at fixed intervals before, immediately after, 30 and 60 minutes after the exercise session and then with 60 minutes interval for another five hours after exercise to monitor the short-term changes of serum COMP. COMP was quantified with a sandwich-ELISA (AnaMar Medical, Lund, Sweden).ResultsBefore exercise or rest no significant differences in COMP levels were seen between the groups. After 60 minutes exercise serum COMP levels increased (p < 0.001). After 60 minutes of rest the serum levels decreased (p = 0.003). Median serum COMP values in samples obtained prior to exercise or rest at baseline and after 24 weeks did not change between start and end of the study. In the second study serum COMP was increased immediately after exercise (p = 0.018) and had decreased to baseline levels after 30 minutes.ConclusionSerum COMP levels increased during exercise in individuals with knee OA, whereas levels decreased during rest. The increased serum COMP levels were normalized 30 minutes after exercise session, therefore we suggest that samples of blood for analysis of serum COMP should be drawn after at least 30 minutes rest in a seated position. No increase was seen after a six-week exercise program indicating that any effect of individualized supervised exercise on cartilage turnover is transient.

Natural course of knee osteoarthritis in middle-aged subjects with knee pain: 12-year follow-up using clinical and radiographic criteria

Objective: To explore the natural course of knee osteoarthritis (OA) in a middle-aged population with chronic knee pain. Methods: A population-based sample of 143 subjects (mean age 45 (range 35–54), 44% women) with knee pain (>3 months) at inclusion was studied. Weight-bearing posteroanterior tibiofemoral (TF) radiographs were obtained at baseline and 12 years later, and classified according to Kellgren/Lawrence (K/L). Patellofemoral (PF) OA was determined at 5- and 12-years’ follow-up using a skyline view and a cut-off point of <5 mm joint space width. The ACR clinical criteria were used at baseline. Results: Seventy-six (53%) had no TF OA (K/L 0) at baseline, but 49 had clinical OA. Overall, 65/76 (86%) developed incident TF OA over 12 years (K/L ⩾1): 44/49 (90%) of the subjects with clinical OA and 21/27 (78%) without clinical OA. Progression was found in 65/67 (97%) with TF OA at baseline. Of the 84 with no PF OA at the 5-year examination, 26 (31%) developed PF OA over 7 years. Conclusion: A majority of the subjects with chronic knee pain developed knee OA over 12 years. It is concluded that knee pain is often the first sign of knee OA.

Identification of phenotypes with different clinical outcomes in knee osteoarthritis: data from the Osteoarthritis Initiative

To identify subgroups or phenotypes of knee osteoarthritis (OA) patients based on similarities of clinically relevant patient characteristics, and to compare clinical outcomes of these phenotypes.

Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort

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.

Patient perspective of hand osteoarthritis in relation to concepts covered by instruments measuring functioning: a qualitative European multicentre study

Objective: To explore whether the concepts important to patients with hand osteoarthritis (OA) are covered by the most commonly used instruments measuring functioning. Method: A qualitative multicentre study using a focus group technique was performed in five European countries: Austria, The Netherlands, Norway, Sweden and the United Kingdom. The qualitative data analysis followed a modified form of “meaning condensation” and used the International Classification of Functioning, Disability and Health (ICF) as a theoretical framework. Finally, the concepts from the focus groups were compared with the content of the most commonly used instruments which had been identified in an earlier theoretical analysis. Results: Fifty-six people (51 women, mean (SD) age 62.7 (7.9) years) with hand OA participated in this study in two focus groups per centre. 63 concepts were extracted from the focus groups. Twenty-one (33%) of the 63 concepts were covered by at least one instrument. Psychological consequences, different qualities of pain, aesthetic changes and leisure activities are important concepts from the focus groups which were not covered by the instruments. The qualitative analysis revealed detailed descriptions of pain-concerning sensations, levels and a certain relation to activity, none of which were fully represented in the instruments routinely used. Conclusion: It was possible to combine the concepts of the focus groups from each centre into a common qualitative analysis. The concepts important to people with hand OA are not fully represented in the most commonly used instruments.

How do middle-aged patients conceive exercise as a form of treatment for knee osteoarthritis?

Purpose. To describe conceptions, as registered by a semi-structured interview, of exercise as treatment among sixteen middle-aged patients with moderate to severe knee osteoarthritis. Method. Sixteen patients (aged 39 – 64) with symptomatic, radiographic knee osteoarthritis and previous participants in an exercise intervention, were interviewed. The qualitative data obtained were analysed using phenomenographic approach. Results. Four descriptive categories containing 13 conceptions emerged: Category 1) To gain health included five conceptions; to experience coherence, to experience well-being, to be in control, to experience improved physical functioning, to experience symptom relief; 2) To become motivated included three conceptions; to experience inspiration, to be prepared to persevere, to experience the need to exercise; 3) To experience the need for support included three conceptions; to have structure, to receive guidance, to devote time; 4) To experience resistance included two conceptions; to hesitate, to deprecate. Conclusion. Patients with knee osteoarthritis and knee pain, previously participating in exercise intervention, are aware of the health benefits of exercise, but have many doubts and concerns about exercise as treatment. These aspects should be considered when designing patient information and treatment programmes. Furthermore, a hesitative and resistive perception of exercise as a concept could have major influences on the implementation of health programmes.

Risk of sick leave and disability pension in working-age women and men with knee osteoarthritis

Objectives To investigate sick leave and disability pension in working-age subjects with knee osteoarthritis (OA) compared with the general population. Methods Population-based cohort study: individual-level inpatient and outpatient Skåne Health Care Register data were linked with data from the Swedish Social Insurance Agency. In 2009 all working-age (16–64 years) Skåne County residents who in 1998–2009 had been diagnosed with knee OA (International Classification of Diseases-10 code M17) were identified and their sick leave and disability pension in 2009 related to those of the general working-age population (n=789 366) standardised for age. Results 15 345 working-age residents (49.6% women) with knee OA were identified. Compared with the general population, the RR (95% CI) of having had one or more episodes of sick leave during the year was 1.82 (1.73 to 1.91) for women and 2.03 (1.92 to 2.14) for men with knee OA. The corresponding risk for disability pension was 1.54 (1.48 to 1.60) for women and 1.36 (1.28 to 1.43) for men with knee OA. The annual mean number of sick days was 87 for each patient with knee OA and 57 for the general population (age- and sex-standardised). Of all sick leave and disability pension in the entire population, 2.1% of days were attributable to knee OA or associated comorbidity in the patients with knee OA (3.1% for sick leave and 1.8% for disability pension). Conclusions Subjects with doctor-diagnosed knee OA have an almost twofold increased risk of sick leave and about 40–50% increased risk of disability pension compared with the general population. About 2% of all sick days in society are attributable to knee OA.