Search

OBJECTIVE The present study was undertaken to assess the comparative responsiveness of outcome measures used for the assessment of pain and function in individuals with osteoarthritis (OA) of the first metatarsophalangeal (MTP) joint. METHODS Eighty-eight patients (mean ± SD age 57.2 ± 10.2 years) with OA of the first MTP joint who participated in a randomized trial completed the Foot Health Status Questionnaire (FHSQ), the Foot Function Index Revised Short Form (FFI-RS), and 100-mm visual analog scales (VAS) of pain and stiffness at baseline and 12 weeks. Responsiveness of the subscales for each outcome measure was determined using paired t-tests, Cohen's d coefficient, the standardized response mean (SRM), and the Guyatt index (GI). Sample size estimations were calculated based on minimal important differences (MIDs). RESULTS All outcome measures were sensitive to change and demonstrated at least medium effect sizes. Three outcome measures exhibited large or very large effect sizes for Cohen's d coefficient, the SRM, and the GI: the FHSQ pain subscale (d = 1.03; SRM 1.10, GI score 1.30), the FFI-RS pain subscale (d = 1.09; SRM 1.05, GI score 1.73), and the 100-mm VAS of pain severity while walking (d = 1.22; SRM 1.07, GI score 1.78). Sample size calculations indicated that between 20 and 33 participants per group would be required to detect MIDs using these measures. CONCLUSION The FHSQ pain subscale, FFI-RS pain subscale, and the 100-mm VAS of pain severity while walking are the most responsive outcome measures for the assessment of pain and function in individuals with OA of the first MTP joint. These findings provide useful information to guide researchers in selecting appropriate outcome measures for use in future clinical trials.

Muscle function is often impaired in patients with knee osteoarthritis (OA), with reduced strength and increased pain. The role of vitamin D and the vitamin D-endocrine pathway in muscle health has recently been placed in the spotlight, with various groups reporting positive effects on muscle development, function and health. Recently, it has been shown that uptake into muscle of the specialized vitamin D binding protein (DBP) is dependent on the endocytic receptor, megalin. Here we analyse circulating vitamin D, and muscle DBP, megalin and the cognate vitamin D receptor (VDR) in patients with knee OA and compare them to asymptomatic controls. Muscle and blood samples were collected from 19 patients with end-stage OA of the knee and 10 age-matched controls. Muscle biopsies from the OA group were performed during knee replacement surgery and a needle biopsy was used on control volunteers. Immunoblots performed with specific antibodies were used to detect the presence of DBP, megalin, VDR (using the specific D-6 antibody) and albumin in the muscle biopsies. Results were correlated with FoxO1, a key regulator of the ubiquitin-proteasome degradation pathway in muscle. There were no differences in circulating levels of 25 (OH) vitamin D3 between the groups, and no subjects were vitamin D deficient. We found increased VDR, DBP and albumin protein in the muscle from patients with OA compared to controls, with no change in muscle megalin expression. Furthermore, DBP levels in the muscle correlated with FoxO1, suggesting an association between muscle protein breakdown and the activation of the vitamin D-endocrine pathway in muscle surrounding an OA affected joint. We show, for the first time, that the factors involved in the vitamin D-endocrine-pathway are present at higher levels in muscles from OA patients compared to asymptomatic controls. This is despite no differences in circulating 25 (OH) vitamin D levels between the groups. These findings indicate the activation of vitamin D pathway in these muscles that may provide a beneficial compensatory stimulation of the repair process in muscles that are subject to inflammatory and proteolytic processes.

Background Total hip/total knee replacement (THR/TKR) surgery is becoming an increasingly common approach for the management of primarily lower limb osteoarthritis. A number of factors such as reducing mobility, structural joint changes, and pain may predispose those awaiting hip and knee surgery to falls, which may impact on pre- and postsurgery functions. The aim of this study was to identify the prevalence of falls in the year preceding THR/TKR surgery, and factors associated with falls. Methods Cross-sectional survey of patients scheduled for THR/TKR, including measures of joint disease severity, falls, falls efficacy, quality of life, pain, and depression. Comparisons across falls status (nonfaller, single faller, or multiple faller) and high/low disease severity for both THR and TKR groups were undertaken. Results A total of 282 people (mean age 67.3 years) completed surveys before the surgery (197 TKR). As much as 41% reported one or more falls in the preceding year, and participants reported that the affected joint contributed to the fall in 35% of the cases. TKR multiple fallers (≥ 2 falls) had significantly lower falls efficacy, worse function, greater pain catastrophizing and depression, and poorer 36-Item Short Form Survey Mental Component Scores than nonmultiple fallers. For both THR and TKR groups, several measures were significantly worse for those with greater disease severity, including falls efficacy, depression, pain catastrophizing, self-rated health, and physical activity. Conclusion Falls are common in the 12 months preceding total hip or knee surgery. A number of factors are associated with risk of multiple falls and with joint disease severity. Strategies to reduce falls risk should be a priority in the year preceding lower limb joint surgery to optimize presurgery and postsurgery outcomes.

Summary Objectives Using a mouse surgical model of post-traumatic osteoarthritis (OA), we sought to determine if muscle function is altered following acute joint injury and whether this relates to OA progression. Design Male C57BL/6 mice underwent surgical transection of the medio-meniscal tibial ligament destabilisation of the medial meniscus (DMM) or sham surgery on one knee. Tibialis anterior (TA) muscle function was assessed in situ at 1, 4 and 8 weeks post-surgery. Cartilage damage and joint inflammation were assessed by histologic scoring. Muscle mRNA expression was quantified by qRT-PCR. Results Tetanic and twitch force production between DMM and sham muscle did not differ at 1 week post-surgery. Muscle function improved in both groups with time, but specific force production in DMM muscles was 18% and 22% lower than sham muscles at 4 and 8 weeks post-surgery respectively. At 8 weeks post-surgery, DMM muscles had a 40% slower relaxation rate and reduced expression of sarcoplasmic/endoplasmic reticulum Ca 2+ ATPase (Serca) pump mRNA compared to sham muscles; both observations indicate likely alterations in muscle Ca 2+ handling. There were no histologic signs of muscle atrophy or inflammation in DMM TA muscles. Specific force production in both sham and DMM mice showed a negative correlation with the severity of joint inflammation. Conclusions Acute knee injury in the DMM model of post-traumatic OA leads to a persistent deficit in TA muscle function that occurs in the absence of muscle atrophy. This study highlights that the impact of acute knee injury is unlikely to be limited to the muscles controlling knee movement.

Objective To evaluate the effects of prefabricated foot orthoses and rocker-sole footwear on spatiotemporal parameters, hip and knee kinematics, and plantar pressures in people with first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods. A total of 102 people with first MTP joint OA were randomly allocated to receive prefabricated foot orthoses or rocker-sole footwear. The immediate biomechanical effects of the interventions (compared to usual footwear) were examined using a wearable sensor motion analysis system and an in-shoe plantar pressure measurement system. Results Spatiotemporal/kinematic and plantar pressure data were available from 88 and 87 participants, respectively. The orthoses had minimal effect on spatiotemporal or kinematic parameters, while the rocker-sole footwear resulted in reduced cadence, percentage of the gait cycle spent in stance phase, and sagittal plane hip range of motion. The orthoses increased peak pressure under the midfoot and lesser toes. Both interventions significantly reduced peak pressure under the first MTP joint, and the rocker-sole shoes also reduced peak pressure under the second through fifth MTP joints and heel. When the effects of the orthoses and rocker-sole shoes were directly compared, there was no difference in peak pressure under the hallux, first MTP joint, or heel; however, the rocker-sole shoes exhibited lower peak pressure under the lesser toes, second through fifth MTP joints, and midfoot. Conclusion Prefabricated foot orthoses and rocker-sole footwear are effective at reducing peak pressure under the first MTP joint in people with first MTP joint OA, but achieve this through different mechanisms. Further research is required to determine whether these biomechanical changes result in improvements in symptoms.

Objective To compare the effectiveness of prefabricated foot orthoses to rocker-sole footwear in reducing foot pain in people with first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods Participants (n = 102) with first MTP joint OA were randomly allocated to receive individualized, prefabricated foot orthoses or rocker-sole footwear. The primary outcome measure was the pain subscale on the Foot Health Status Questionnaire (FHSQ) at 12 weeks. Secondary outcome measures included the function, footwear, and general foot health subscales of the FHSQ; the Foot Function Index; severity of pain and stiffness at the first MTP joint; perception of global improvement; general health status; use of rescue medication and co-interventions to relieve pain; physical activity; and the frequency of self-reported adverse events. Results The FHSQ pain subscale scores improved in both groups, but no statistically significant difference between the groups was observed (adjusted mean difference 2.05 points, 95% confidence interval [95% CI] −3.61, 7.71; P = 0.477). However, the footwear group exhibited lower adherence (mean ± SD total hours worn 287 ± 193 versus 448 ± 234; P < 0.001), were less likely to report global improvement in symptoms (39% versus 62%; relative risk [RR] 0.63, 95% CI 0.41, 0.99; P = 0.043), and were more likely to experience adverse events (39% versus 16%; RR 2.47, 95% CI 1.12, 5.44; P = 0.024) compared to the orthoses group. Conclusion Prefabricated foot orthoses and rocker-sole footwear are similarly effective at reducing foot pain in people with first MTP joint OA. However, prefabricated foot orthoses may be the intervention of choice due to greater adherence and fewer associated adverse events.

This systematic review evaluated the available evidence for the effects of Masai Barefoot Technology (MBT) footwear on lower limb biomechanics during gait. Electronic databases (MEDLINE, EMBASE, CINAHL, SPORTDiscus, and PubMed) were searched in January 2015. Methodological quality of included studies was evaluated using the Quality Index. Standardised mean differences and 95% confidence intervals were calculated, and meta-analysis was conducted where possible. 17 studies satisfied the inclusion criteria; 16 cross-sectional studies and one randomised control trial (RCT). Quality Index scores ranged from 7 to 12 (out of 15). All 17 studies investigated walking gait only. Evidence showed that MBT footwear caused asymptomatic individuals to walk with a shorter stride length, reduced peak hip flexion, increased peak knee extension, and reduced hip and knee range of motion throughout gait. All kinematic effects occurred in the sagittal plane. There was a trend towards a decrease in internal and external joint moments and power, except for the foot, where increases in force were observed. There were only a small number of changes to lower limb muscle amplitude and timing. No statistically significant effects were observed in symptomatic individuals with knee osteoarthritis or following total knee replacement, but there was an increase in cadence and a decrease in step length in individuals following tibiotalar arthrodesis. These findings suggest that MBT footwear does change lower limb biomechanics in both asymptomatic and symptomatic individuals during gait. However, further clinical trials need to be undertaken to determine whether these changes are therapeutically beneficial.

To explore the perceptions of people with severe knee osteoarthritis and increased cardiovascular risk about participating in a walking program.Qualitative study using semistructured interviews for people with severe knee osteoarthritis and increased cardiovascular risk who participated in a 12-week walking program. Interviews were audiotaped, transcribed verbatim, member-checked, coded and themes developed using thematic analysis. Findings were triangulated with quantitative data including pain, function and cardiovascular risk factors from previously reported data.Twenty-one participants were interviewed after the completion of the walking program. The main theme identified was the preoccupation with the knee including pain, damage and the view that surgery was required. Three subthemes to emerge were (i) the perception of functional, cardiovascular and psychosocial benefits with the walking program; (ii) that supervision, monitoring and commitment were important enablers; and (iii) external factors such as ill-health, weather and the environment were key barriers. The perceived functional and cardiovascular benefits converged with results from quantitative data.Even when patients with severe osteoarthritis of the knee report other benefits from participating in a walking program, the core theme to emerge was their preoccupation with knee pain, knee damage and the view that they needed a knee replacement. Implications for Rehabilitation Patients with severe osteoarthritis of the knee and moderate cardiovascular risk reported functional, cardiovascular and psychosocial benefits from participating in a walking program. Despite patients reporting functional, cardiovascular and psychosocial benefits, the core theme to emerge was their preoccupation with knee pain, knee damage and the view that they needed a knee replacement. The core theme highlights the challenges in promoting physical activity for patients with severe knee osteoarthritis.

Summary Objective To determine how much physical activity, in the form of walking, can be safely and feasibly tolerated for people with severe knee osteoarthritis (OA). Design Phase I dose response trial with escalating walking doses of 10, 20, 35, 50, 70, and 95 min over 1 week, were prescribed non-randomly to people with severe knee OA. The primary stopping rule was a substantial increase in knee pain. The primary outcomes were an estimation of the maximum tolerated dose of walking; and the proportion of people who did not complete the dose for feasibility reasons. The secondary outcomes were pain, stiffness and activity limitation Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results Twenty-four participants (13 women) aged 53–83 years, and average body mass index (BMI) of 34 kg/m 2 (SD 9) were recruited. Three participants were assigned to each dose between 10 and 70 min, and nine participants assigned to the 95-min dose. The trial was stopped at 95 min due to the maximum number of adverse events occurring at this dose. Therefore, the maximum tolerated dose was 70 min. No participant stopped due to reasons related to feasibility. There was a moderate association between dose and increased activity (linear R 2 = 0.31, cubic R 2 = 0.69) and reduced stiffness (linear R 2 = 0.20, cubic R 2 = 0.52), with increased benefits at moderate to higher doses. Conclusions There is preliminary evidence that 70 min per week of moderate intensity supervised walking was safe and feasible for people with severe OA of the knee; for higher doses there was a risk of exacerbating knee pain levels.

Summary The association between vitamin D and muscle function associated with balance recovery and falls in people with knee osteoarthritis is unclear. Those with vitamin D insufficiency demonstrated poorer knee function during balance recovery, greater pain and locomotor dysfunction. Vitamin D insufficiency may have an adverse effect on muscle power function. Purpose Low vitamin D status in people with knee osteoarthritis (OA) is often reported to be associated with increased pain and locomotor dysfunction. However, despite the growing evidence of the effect of vitamin D on the pathogenesis of knee OA, its role remains conflicting. Importantly, muscle function is important for knee joint health; however, the association between vitamin D levels and muscle function associated with balance recovery and falls is unclear. This study investigated the effect of circulating 25-hydroxyvitamin D (25 (OH) D) on pain, quadriceps strength, lower limb muscle mass and knee power function during balance recovery in people with knee OA. Methods Twenty-four participants with clinical symptoms of knee OA (68.6 ± 6.2 years) participated in the study. Serum levels of 25 (OH) D were assessed and participants were classified as follows: vitamin D insufficiency ≤ 50 nmol/L and vitamin D sufficiency > 50 nmol/L. The groups were compared on knee function during balance recovery tasks, lower limb strength and muscle mass as well as perceived pain and function. Results Seven patients (29.1%) were classified as vitamin D-insufficient. Vitamin D insufficiency was associated with reduced knee muscle function during the balance recovery task, increased pain (Western Ontario and McMasters University Osteoarthritis Index (WOMAC) subscore), dysfunction (WOMAC subscore) and total WOMAC score (p < 0.05). Conclusion People with knee OA with vitamin D insufficiency demonstrated poorer knee function during balance recovery, greater pain and locomotor dysfunction. Vitamin D insufficiency may have an adverse effect on muscle power function.

Background The number of falls experienced by people with knee osteoarthritis (OA) is almost double the number experienced by people with no OA. The neuromuscular elements required to arrest a fall are more impaired in people with knee OA compared to their asymptomatic counterparts. Therefore, these elements may need to be incorporated into an exercise intervention to reduce the risk of falling. The aim of this study will be to examine the feasibility, safety and patient satisfaction of a high-speed resistance-training program, with and without balance exercises, in people with knee OA compared to a control group. The effect of these exercise programs on lower-limb muscle strength and physiological and functional risk factors for falls will also be examined. Methods This study will be a pilot randomized controlled trial with a pre- and post-intervention design (outcome assessments at baseline and 8 weeks after participation commencement) comparing three groups: a control group (no intervention), a high-speed resistance-training group and a high-speed resistance-training plus balance exercises group. Thirty people with knee osteoarthritis aged 60–90 years will be recruited and randomized to one of the three groups. Feasibility and safety will be assessed by examining adherence to the exercise program, dropout rate, pain level during and following exercise, number of exercises stopped due to pain, and any adverse event or any incident that prevents the participant from completing the prescribed exercise. Secondary measures of lower-limb strength, physical function, self-reported pain and function, fear of falls, and executive function and quality of life will also be assessed. To determine statistical trends of effectiveness and hence to inform sample size for a fully powered study, analyses of the secondary outcomes will be performed to assess the changes within and between groups over time (pre-post) using repeated measure ANOVA. Discussion The results of this study will improve understanding of what type of exercise is safe and beneficial for people with knee OA to reduce their risk of falling, and hence will inform the development of a future large research trial. Trial registration Australian New Zealand Clinical Trials Registry, ID: ACTRN12616001382460. Registered on 6 October 2016. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-2129-7) contains supplementary material, which is available to authorized users.

To determine if a pre-operative group rehabilitation programme can improve arthritis self-efficacy for people with severe hip and knee osteoarthritis.Single group, repeated measures design: 4-week baseline phase followed by a 6-week intervention phase of water exercise, and education with self-management strategies. The primary outcome was arthritis self-efficacy. The secondary outcomes were measures of pain (WOMAC), activity limitation (WOMAC), activity performance (30 s chair stand test, 10 m walk test) and health-related quality of life (EuroQol).Twenty participants (10 knee osteoarthritis and 10 hip osteoarthritis) with a mean age of 71 years (SD 7) attended 92% (SD 10%) of the scheduled sessions. All measures demonstrated baseline stability between two time points for measurements at week 1 and measurements at week 4. After the 6-week intervention programme there were no significant improvements for arthritis self-efficacy. There was a 12% increase for fast walking speed (mean increase of 0.14 m/s, 95% CI 0.07, 0.22). There were no significant improvements for other secondary outcomes.A pre-operative water-based exercise and educational programme did not improve arthritis self-efficacy, self-reported pain and activity limitation, and health-related quality of life for people with hip and knee osteoarthritis who were candidates for joint replacement. While there was a significant increase in one measure of activity performance (walking speed), these findings suggest the current programme may be of little value. Implications for Rehabilitation This pre-operative group rehabilitation programme for people with severe hip and knee osteoarthritis did not change arthritis self-efficacy, pain, activity limitation and health-related quality of life. This programme may have little value in preparing people for joint replacement surgery. The optimal pre-operative programme requires further design and investigation.

Pain and disability often persist following hip (THR) and knee replacement (TKR) surgery predisposing patients to increased risk of falling. This study identified pre-operative predictors for post-operative falls in TKR and THR patients, and the incidence and circumstances of falls in the 12 months post-surgery. A survey was undertaken of patients before THR and TKR, and was repeated 12 months post-operation. The survey included (1) medical history and medications usage, (2) pain and function, (3) health-related and physical activity and (4) fear of falls and history of falls questionnaires. Patients were classified as ‘fallers’ (≥1 fall) or ‘non-fallers’ based on prospectively documented falls in the 12 months post-surgery. Binary logistic regression was conducted to identify independent pre-operative predictors of incident falls status. Eighty-two of the 243 participants (33.7%) reported ≥1 fall in the 12 months post-operatively [60 (34.1%) patients following TKR and 22 (32.8%) following THR]. The logistic regression model was statistically significant, χ 2 = 24.731, p

Summary Objective The primary aim was to evaluate the effect of a dosed walking program on knee pain for patients with severe knee osteoarthritis (OA). Secondary aims evaluated the effects on cardiovascular health, function and quality of life. Design Participants with severe knee OA and increased cardiovascular risk were randomly assigned to a 12-week walking program of 70 min/week of at least moderate intensity, or to usual care. The primary outcome was knee pain (0–10). Secondary outcomes were of cardiovascular risk including physical activity, blood pressure, blood lipid and glucose levels, body mass index and waist circumference; WOMAC Index scores; physical function; and quality of life. Results Forty-six participants (23 each group) were recruited. Sixteen participants (70%) adhered to the walking program. Intention to treat analysis showed no between-group difference in knee pain. The walking group had increased odds of achieving a healthy systolic blood pressure (OR = 5.7, 95% CI 1.2–26.9), and a faster walking speed (Mean Difference (MD) = 0.12 m/s, 95% CI 0.02–0.23). Per protocol analysis based on participant adherence showed the walking group had more daily steps (MD = 1345 steps, 95% CI 365–2325); more time walking (MD = 18 min/day, 95% CI 5–31); reduced waist circumference (MD = −5.3 cm, 95% CI −10.5 to −0.03); and increased knee stiffness (MD = 0.9 units, 95% CI 0.07–1.8). Conclusions Patients with severe knee OA prescribed a 12-week walking program of 70 min/week may have had cardiovascular benefits without decreasing knee pain. Australian New Zealand Clinical Trials Registry ACTRN12615000015549.

AIM: We investigated differences in function, strength and pain in those with knee osteoarthritis (OA) who responded with a single step compared to multiple steps during balance recovery during an induced forward fall. METHOD: The stepping response of 24 participants with knee OA (50% female, age 68.6 ± 6.2 years) as they recovered balance from an induced forward fall was recorded. Participants were grouped based on their stepping response as single-stepper and multi-stepper. Comparison was made between the groups for functional and strength tests and self-reported pain, function, quality of life, fear of falls and physical activity. RESULTS: Fourteen of the participants (58%) responded with a multiple step response. Multiple steppers demonstrated greater time for the up and go (P = 0.01), the stair climb tests (P = 0.05), as well as reduced distance during the 2 min walk test (P = 0.001) and reduced isokinetic knee extension strength (P = 0.02). CONCLUSION: Those who demonstrated multiple step response had impaired function, reduced strength and were less physically active. Given the high prevalence of falls in people with knee OA, further studies are required to better understand the ability of people with knee OA to respond and avoid falls.© 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd. Language: en

s / Osteoarthritis and Cartilage 24 (2016) S63eS534 S92 143 BALANCE RECOVERY DURING INDUCED FALLS IS IMPAIRED IN PEOPLE WITH KNEE OSTEOARTHRITIS: IMPLICATIONS FOR FALLS PREVENTION P. Levinger y, H. Nagano y, C. Downie y, A. Hayes y, K. Sanders z, F. Cicuttini x, R. Begg y. yVictoria Univ., Melbourne, Australia; zAustralian Catholic Univ., Melbourne, Australia; xMonash Univ., Melbourne, Australia Purpose: Knee osteoarthritis (OA) is a major risk factor for falls with high falls rates reported; 50% in people with knee OA who are over the age of 60. Increased neuromuscular deficits are common in people with knee OAwhichmay further impact on postural control mechanisms and the ability to defend against a fall. Despite the high prevalence of falls in people with knee OA, the mechanism of falling in this group is unclear. This study investigated the biomechanical response of the lower limb joints during a forward induced fall under different task conditions in people with knee OA. Moreover, the balance recovery step responses (single vs multi steps) were also investigated to determine how dynamic postural control would be affected due to the presence of knee OA while undertaking the three task conditions. Methods: Twenty four participants with knee OA (68.6± 6.2 years) and fifteen asymptomatic healthy controls (72.4± 4.8 years) participated in the study. Forward fallwas induced by releasing participants froma static forward leaning position. Participants were required to recover balance during three conditions: normal, physical dual task (obstacle clearance) and cognitive dual task (counting backwards). Spatiotemporal parameters, lower limb joint kinematics and kinetics of the recovery limb were compared between the two groups and across the three task conditions using two way full factorial Multiple Analyses of Covariate (MANCOVA) with Bonferroni-adjusted post-hoc tests with age as a covariate. Results: TheOAgroupdemonstrated significantly slower spatio-temporal characteristics and reduced hip and knee flexion angles, joint moments/ powers and lower knee and ankle negative works. Cognitive dual task resulted in reduced centre of mass velocity and step length (p1⁄4 0.03) compared to the physical dual task condition. Reduced knee (p1⁄4 0.02) and hip powers (p1⁄4 0.03) were demonstrated in the OA group during the dual task conditions especially obstacle clearance where additional cognitive demand was required. The number of participants who responded with multi steps was similar for both groups during normal balance recovery task (60%; p>0.05). Although not significant, with increased task complexity the number of multi-step responders increased in the OA group compared to the control (75% for OA vs 60% for control during the obstacle task and 83% for OA vs 60% for control during the cognitive task). Conclusions: When simulating a forward fall, participants with knee OA demonstrated difficulty in absorbing the impact and slowing down the forward momentum of the body during a recovery step. Differences in biomechanical response of the hip and knee were identified which could provide useful and important information regarding the strategies used by people with knee OA to recover balance and avoid a potential fall. Poor dynamic postural control was also demonstrated when required to simultaneously recover balance and attend to a secondary task such as obstacle clearance and cognitive task. As task complexity increased (i.e. use of physical/cognitive dual task), poor recovery strategies (multiple steps) were used more often in the knee OA group. Hence, balance impairment may be further exacerbated by impaired attention dynamics in people with knee OA. 144 TIBIOFEMORAL CONTACT FORCES 2e3 YEARS FOLLOWING ANTERIOR CRUCUATE LIGAMENT RECONSTRUCTION: A COMPARISON WITH HEALTHY INDIVIDUALS D.J. Saxby y, A.L. Bryant z, L. Modenese y, P. Gerus x, B. Killen y, J. Konrath y, K. Fortin z, T.V. Wrigley z, K.L. Bennell z, F.M. Cicuttini k, C. Vertullo y, J.A. Feller ¶, T. Whitehead#, P. Gallie yy, D.G. Lloyd y. yCtr. for Musculoskeletal Res., Menzies Hlth.Inst. Queensland, Griffith Univ., Gold Coast, Australia; zCtr. for Hlth., Exercise and Sports Med., Univ. of Melbourne, Melbourne, Australia; x Lab. of Human Motion, Ed. and Hlth., Univ. of Nice Sophia-Antipolis, Nice, France; kDept. of Epidemiology and Preventive Med., Monash Univ., Melbourne, Australia; Coll. of Sci., Hlth.and Engineering, La Trobe Univ., Melbourne, Australia; OrthoSport Victoria, Melbourne, Australia; yy Pacific Private Clinic, Gold Coast, Australia Purpose: Due to the risk of osteoarthritis development in those with anterior cruciate ligament (ACL) rupture and reconstruction (ACLR), we need to better understand in vivo articular contact loading in ACLR knees. To date, few studies have explored in vivo tibiofemoral contact forces in ACLR knees, and of those studies the examination has focused on affected and unaffected limbs, considered only females and/or been confined to small sample sizes. As a result, it remains unclear whether the ACLR tibiofemoral contact forces are comparable with healthy individuals, or whether they are peculiar in some way. The purpose of this study was to compare in vivo tibiofemoral contact forces in a large sample of ACLR individuals and healthy controls during normal walking and sporting gait tasks. Methods: This cross-sectional study was conducted at Griffith University’s Centre for Musculoskeletal Research (CMR) and University of Melbourne’s Centre for Health, Exercise and Sports Medicine (CHESM) (ethics approvals CMR: PES/36/10/HREC, CHESM: 0932864.3). Both ACLRs (68% male, n1⁄4 107, 29.7 ± 6.5 years, 78.1± 14.4 kg) and healthy controls (58% male, 27.5 ± 5.4 years, 67.8± 14.0 kg) participated. ACLRs were tested 2e3 years after a single combined hamstrings autograft reconstruction (2.51± 0.44 years). All participants underwent comprehensive 3-dimensional gait analysis wherein they walked (1.42 ± 0.20 m.s-1), ran (4.46± 0.46 m.s-1) and ran with a 45 diagonal sidestep (3.66± 0.60 m.s-1). Gait tasks were performed shod (Dunlop Volleys), and surface electromyography (EMG) was performed on the eight major muscles (rectus femoris, vastii, gastrocnemii, hamstrings, tensor fasciae latae) on the reconstructed (ACLRs) or randomized (controls) knee. From the gait analysis data, joint kinematics and kinetics were determined using OpenSim, and an EMG-driven neuromusculoskeletal model was then developed for each subject to determine their in vivo tibiofemoral contact forces during the different gait tasks. Analyses of variance were performed to determine if main and interaction effects existed for group (ACLR and controls) and gait task (walk, run, sidestep). If significant effects were found, ttests with Bonferroni corrections were applied to assess specific differences. Results: ACLRs and controls were of similar age, sex, tested limb-side and height, and had similar spatiotemporal parameters (i.e. velocity, cadence, etc...) during the different gait tasks. Compared to controls, ACLRs had a significantly smaller peak flexion angle, excursion and moment during running (angle: 41.4 ± 6 vs 44± 5.9 , excursion: 32.4 ± 5.4 vs 34.4 ± 4.6 , and moment: 0.25± 0.08 Nm.kg-1 vs 0.29 ± 0.06 Nm.kg-1) and sidestepping (angle: 50.6± 6.9 vs 53.4 ± 7.3 , excursion: 39.9 ± 6.7 vs 42.5 ± 7.1 , and moment: 0.29 ± 0.1 Nm.kg-1 vs 0.33 ± 0.1 Nm.kg-1) (all p

Objectives. Foot orthoses are commonly used in the management of knee OA, although the relationship between foot function and knee OA is still unclear. The purpose of the study was to examine foot function during walking in people with and without medial compartment knee OA. Methods. Motion of the tibia, rearfoot and forefoot in 32 patients with medial compartment knee OA and 28 age-matched control subjects was investigated. Multivariate analysis was used to compare the groups. Results. The knee OA group contacted the ground with a more everted rearfoot, demonstrated greater peak rearfoot eversion and exhibited reduced rearfoot frontal plane range of motion and reduced rearfoot peak inversion. The tibia was more internally rotated and laterally tilted throughout the gait cycle, with reduced peak external rotation. Conclusion. People with medial compartment knee OA exhibit altered foot kinematics during gait that are indicative of a less mobile, more everted foot type. The presence and degree of tibial malalignment and the available rearfoot range of motion during walking may affect individual responses to load-altering interventions, such as foot orthoses and footwear modifications. Trial registration: Australian New Zealand Clinical Trials Registry, www.anzctr.org.au/, ACTRN

Objective Knee osteoarthritis (OA) has been shown to be a risk factor for falls. Reductions in foot clearance during the swing phase of walking can cause a trip and potentially lead to a fall. This study examined the swing phase mechanics of people with and without knee OA during walking. Design Minimum toe clearance (MTC) height, joint angles at the time of MTC and the influence of the angular changes of the hip, knee and ankle of the swing leg on foot clearance using sensitivity analysis were investigated in 50 knee OA participants and 28 age-matched asymptomatic controls. Results Although both groups had a similar MTC height (controls: 12.8 ± 6.7 mm, knee OA: 13.4 ± 7.0 mm), the knee OA group used a different strategy to achieve the same foot clearance, as evidenced by greater knee flexion (52.5 ± 5.3° vs 49.4 ± 4.8°, p = 0.007), greater hip abduction (−3.6 ± 3.3° vs −1.8 ± 3.3°, p = 0.03) and less ankle adduction (2.8 ± 1.9° vs 4.2 ± 2.1°, p = 0.01). Conclusion MTC height was comparable between the groups, however a different swing phase mechanism was used by the knee OA. Although adequate MTC is an important component of safe locomotion, it does not appear to be impaired in people with knee OA. Other factors, such as inadequate responses to postural perturbation, may be responsible for falls in this group.

Knee osteoarthritis (OA) is a major cause of disability and a risk factor for falls in older people. The purpose of this study was to assess the falls risk of people with knee OA before surgery and at 4 months following surgery and to compare this to a control group. Thirty-five patients with knee OA prior to undergoing knee replacement surgery and 27 asymptomatic age-matched controls participated in the study. The surgical group were tested prior to their surgery and at 4 months post-surgery. The short form of the Physiological Profile Assessment was used to assess falls risk and included tests of vision, lower limb proprioception, knee extension strength, reaction time and postural sway. Physical activity, quality of life, fear of falls and disability before and after surgery were also documented. At least one fall in the previous 12 months was reported for 48% of the surgical group compared with 30% of the control group. Following the surgery, there was a reduction in fear of falling and pain, and improvements in function for the surgical group. However, compared to the control group, the surgical group exhibited a greater fear of falling and reduced lower limb proprioception and knee extension strength both pre- and post-surgery. People who undergo knee replacement surgery may be at increased risk of falls both prior to and 4 months following their surgery, primarily due to deficits in knee extension strength and lower limb proprioception. Therefore, interventions to reduce the risk of falls should be implemented early after the surgery.

Increased load on the knee joint by excessive levels of impact forces during initial contact has been suggested to lead to knee osteoarthritis (OA). Asymmetric loading after knee replacement may also relate to the development of OA in the contralateral limb, therefore this study investigated the heel strike transient vertical force and subsequent lower extremity kinematic, kinetic and spatio-temporal parameters during level walking between the operated and the contralateral limbs in patients 12 months following unilateral knee replacement. A six camera motion analysis system with a force plate was used to investigate the differences between limbs in the heel strike transient vertical GRF and its relative timing, and hip, knee and ankle angles and moments at initial contact, as well as spatio-temporal parameters during the stance phase of walking in 19 subjects with unilateral knee replacement. Paired t tests showed a significant difference in the contralateral limb relative to the operated limb in the heel strike transient magnitude (p=0.03), hip moment (p=0.01), knee moment (p=0.02) and ankle moment (p=0.03). No significant differences were found for the joint angles at heel contact or the spatio-temporal parameters (p>0.05). The heel strike transient magnitude was lower for the operated limb with no differences in the spatio-temporal parameters or the joint angles at initial contact between the limbs. Differences in the hip, knee and ankle moments were also found indicating an asymmetric loading of the impact force at initial contact on the lower extremity. The current findings may indicate an asymmetric loading on the knee joint and therefore may be clinically relevant in patients undergoing unilateral knee replacement.

People with knee osteoarthritis (OA) are at twice the risk of falling compared to older people without knee OA, however the mechanism for this is poorly understood. This study investigated the biomechanical response of the trunk and lower limb joints during a forward induced fall under different task conditions in people with and without knee OA.Twenty-four participants with OA (68.6±6.2 years) and 15 asymptomatic controls (72.4±4.8 years) participated in the study. Forward fall was induced by releasing participants from a static forward leaning position. Participants were required to recover balance during three conditions: normal, physical (obstacle clearance) and cognitive dual tasks (counting backwards). Spatiotemporal parameters, lower limb joint kinematics and kinetics of the recovery limb were compared between the two groups and across the three task conditions.The OA group demonstrated slower spatio-temporal characteristics and reduced hip and knee flexion angles, joint moments/powers and reduced muscle negative work at the knee and ankle (p0.05). Cognitive dual task resulted in reduced centre of mass velocity and step length (p=0.03) compared to the physical dual task condition. Reduced knee (p=0.02) and hip joint powers (p=0.03) were demonstrated in the OA group in the physical task condition.When simulating a forward fall, participants with OA demonstrated difficulty in absorbing the impact and slowing down the forward momentum of the body during a recovery step. Moreover, poor dynamic postural control was demonstrated as task complexity increased.

The molecular regulation of muscle function in knee osteoarthritis is unclear. Elevated muscle atrophy regulation marker expression was associated with reduced muscle strength in knee osteoarthritis. The level of protein expression appears to be different between muscle, knee joint and serum, suggesting that inflammation is regulated differently within these tissues. Impaired muscle function is common in knee osteoarthritis (OA). Numerous biochemical molecules have been implicated in the development of OA; however, these have only been identified in the joint and serum. We compared the expression of interleukin-15 (IL-15) and Forkhead box protein-O1 (FoxO1) in muscle of patients with knee OA and asymptomatic individuals and examined whether IL-15 was also present in the joint and serum. Muscle and blood samples were collected from 19 patients with knee OA and 10 age-matched asymptomatic individuals. Synovial fluid and muscle biopsies were collected from the OA group during knee replacement surgery. IL-15 and FoxO1 were measured in the skeletal muscle. IL-15 abundance was also analysed in the serum of both groups and synovial fluid from the OA group. Knee extensor strength was measured and correlated with IL-15 and FoxO1 in the muscle. FoxO1 protein expression was higher (p = 0.04), whereas IL-15 expression was lower (p = 0.02) in the muscle of the OA group. Strength was also lower in the OA group and was inversely correlated with FoxO1 expression. No correlation was found between IL-15 in the joint, muscle or serum. Skeletal muscle, particularly the quadriceps, is affected in people with knee OA where elevated FoxO1 protein expression was associated with reduced muscle strength. While IL-15 protein expression in the muscle was lower in the knee OA group, no correlation was found between the expression of IL-15 protein in the muscle, joint and serum, which suggests that inflammation is regulated differently within these tissues. Australian Clinical Trials Registry (ACTR) number: ACTRN12613000467730 ( http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12613000467730&isBasic=True )

Objective To evaluate the effects of prefabricated foot orthoses and rocker‐sole footwear on spatiotemporal parameters, hip and knee kinematics, and plantar pressures in people with first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods. A total of 102 people with first MTP joint OA were randomly allocated to receive prefabricated foot orthoses or rocker‐sole footwear. The immediate biomechanical effects of the interventions (compared to usual footwear) were examined using a wearable sensor motion analysis system and an in‐shoe plantar pressure measurement system. Results Spatiotemporal/kinematic and plantar pressure data were available from 88 and 87 participants, respectively. The orthoses had minimal effect on spatiotemporal or kinematic parameters, while the rocker‐sole footwear resulted in reduced cadence, percentage of the gait cycle spent in stance phase, and sagittal plane hip range of motion. The orthoses increased peak pressure under the midfoot and lesser toes. Both interventions significantly reduced peak pressure under the first MTP joint, and the rocker‐sole shoes also reduced peak pressure under the second through fifth MTP joints and heel. When the effects of the orthoses and rocker‐sole shoes were directly compared, there was no difference in peak pressure under the hallux, first MTP joint, or heel; however, the rocker‐sole shoes exhibited lower peak pressure under the lesser toes, second through fifth MTP joints, and midfoot. Conclusion Prefabricated foot orthoses and rocker‐sole footwear are effective at reducing peak pressure under the first MTP joint in people with first MTP joint OA, but achieve this through different mechanisms. Further research is required to determine whether these biomechanical changes result in improvements in symptoms.

While training upregulates skeletal muscle Na(+), K(+)-ATPase (NKA), the effects of knee injury and associated disuse on muscle NKA remain unknown. This was therefore investigated in six healthy young adults with a torn anterior cruciate ligament, (KI; four females, two males; age 25.0 ± 4.9 years; injury duration 15 ± 17 weeks; mean ± SD) and seven age- and BMI-matched asymptomatic controls (CON; five females, two males). Each participant underwent a vastus lateralis muscle biopsy, on both legs in KI and one leg in CON. Muscle was analyzed for muscle fiber type and cross-sectional area (CSA), NKA content ([(3)H]ouabain binding), and α1-3 and β1-2 isoform abundance. Participants also completed physical activity and knee function questionnaires (KI only); and underwent quadriceps peak isometric strength, thigh CSA and postural sway assessments in both injured and noninjured legs. NKA content was 20.1% lower in the knee-injured leg than the noninjured leg and 22.5% lower than CON. NKA α2 abundance was 63.0% lower in the knee-injured leg than the noninjured leg, with no differences in other NKA isoforms. Isometric strength and thigh CSA were 21.7% and 7.1% lower in the injured leg than the noninjured leg, respectively. In KI, postural sway did not differ between legs, but for two-legged standing was 43% higher than CON. Hence, muscle NKA content and α2 abundance were reduced in severe knee injury, which may contribute to impaired muscle function. Restoration of muscle NKA may be important in rehabilitation of muscle function after knee and other lower limb injury.

The discrepancy between patient-desired outcomes and achievable functional outcomes is a source of patient dissatisfaction. This paper reports development and validation of a questionnaire to assess this discrepancy in patients undergoing knee replacement surgery. The initial questionnaire (Knee Surgery Perception Questionnaire, KSPQ) comprised two parts. Part A, assessed patients’ perception of their current level of function and pain, and Part B, assessed patients’ desired outcomes of the surgery. Validation was carried out for Part A and then applied to Part B using a one-factor congeneric model and was tested in 185 patients preceding surgery. A discrepancy score between patients’ expectations and desired outcome (Part B) and their perception of current function (Part A) was also calculated. Pearson correlations were used between the KSPQ total score and subscales and other knee-specific questionnaires to determine construct validity. The final best set of models included four items for each subscale with a Chi-square value of 7.3 (n.s). The subscales and the total KSPQ showed significant strong to moderate correlations with knee-specific questionnaires. The discrepancy score in each subscale and the overall score showed relatively large discrepancy between patients’ expectations and their perception of current function; with higher discrepancy score reported for pain and walking. The KSPQ is a valid questionnaire to assess patients’ expected and desired outcomes of knee replacement surgery and their perception of their current abilities and function, and discrepancy between these. The KSPQ now requires further investigation at different stages of recovery following surgery. III.

Background Osteoarthritis affecting the first metatarsophalangeal joint of the foot is a common condition which results in pain, stiffness and impaired ambulation. Footwear modifications and foot orthoses are widely used in clinical practice to treat this condition, but their effectiveness has not been rigorously evaluated. This article describes the design of a randomised trial comparing the effectiveness of rocker-sole footwear and individualised prefabricated foot orthoses in reducing pain associated with first metatarsophalangeal joint osteoarthritis. Methods Eighty people with first metatarsophalangeal joint osteoarthritis will be randomly allocated to receive either a pair of rocker-sole shoes (MBT® Matwa, Masai Barefoot Technology, Switzerland) or a pair of individualised, prefabricated foot orthoses (Vasyli Customs, Vasyli Medical™, Queensland, Australia). At baseline, the biomechanical effects of the interventions will be examined using a wireless wearable sensor motion analysis system (LEGSys™, BioSensics, Boston, MA, USA) and an in-shoe plantar pressure system (Pedar®, Novel GmbH, Munich, Germany). The primary outcome measure will be the pain subscale of the Foot Health Status Questionnaire (FHSQ), measured at baseline and 4, 8 and 12 weeks. Secondary outcome measures will include the function, footwear and general foot health subscales of the FHSQ, severity of pain and stiffness at the first metatarsophalangeal joint (measured using 100 mm visual analog scales), global change in symptoms (using a 15-point Likert scale), health status (using the Short-Form-12® Version 2.0 questionnaire), use of rescue medication and co-interventions to relieve pain, the frequency and type of self-reported adverse events and physical activity levels (using the Incidental and Planned Activity Questionnaire). Data will be analysed using the intention to treat principle. Discussion This study is the first randomised trial to compare the effectiveness of rocker-sole footwear and individualised prefabricated foot orthoses in reducing pain associated with osteoarthritis of the first metatarsophalangeal joint, and only the third randomised trial ever conducted for this condition. The study has been pragmatically designed to ensure that the findings can be implemented into clinical practice if the interventions are found to be effective, and the baseline biomechanical analysis will provide useful insights into their mechanism of action. Trial registration Australian New Zealand Clinical Trials Registry: ACTRN12613001245785

Knee osteoarthritis (OA) is a debilitating disorder prevalent in older populations that is accompanied by declines in muscle mass, strength, and physical activity. In skeletal muscle, the Na+-K+ pump (NKA) is pivotal in ion homeostasis and excitability and is modulated by disuse and exercise training. This study examined the effects of OA and aging on muscle NKA in 36 older adults (range 55–81 yr), including 19 with OA (69.9 ± 6.5 yr, mean ± SD) and 17 asymptomatic controls (CON, 66.8 ± 6.4 yr). Participants completed knee extensor strength testing and a physical activity questionnaire. A vastus lateralis muscle biopsy was analyzed for NKA content ([3H]ouabain binding sites), α1–3- and β1–3-isoform protein abundance (immunoblotting), and mRNA (real-time RT-PCR). The association between age and NKA content was investigated within the OA and CON groups and in pooled data. The NKA content was also contrasted between subgroups below and above the median age of 68.5 yr. OA had lower strength (−40.8%, P = 0.005), but higher NKA α2- (∼34%, P = 0.006) and α3-protein (100%, P = 0.016) abundance than CON and performed more incidental physical activity ( P = 0.035). No differences were found between groups for NKA content, abundance of other NKA isoforms, or gene expression. There was a negative correlation between age and NKA content within OA ( r = −0.63, P = 0.03) and with both groups combined ( r = −0.47, P = 0.038). The NKA content was 25.5% lower in the older (69–81 yr) than in the younger (55–68 yr) subgroup. Hence older age, but not knee OA, was related to lowered muscle NKA content in older adults.

Objective To determine the proportion of people with hip and knee osteoarthritis that meet physical activity guidelines recommended for adults and older adults. Method Systematic review with meta-analysis of studies measuring physical activity of participants with hip and knee osteoarthritis using an activity monitor. Physical activity levels were calculated using the mean average [95% confidence interval (CI)] weighted according to sample size. Meta-analyses determined the proportion of people meeting physical activity guidelines and recommendations of (1) ≥150 min per week of moderate to vigorous physical activity (MVPA) in bouts of ≥10 min; (2) ≥150 min per week of MVPA in absence of bouts; (3) ≥10,000 steps per day and ≥7000 steps per day. The Grades of Research, Assessment, Development and Evaluation (GRADE) approach was used to determine the quality of the evidence. Results For knee osteoarthritis, 21 studies involving 3266 participants averaged 50 min per week (95% CI = 46, 55) of MVPA when measured in bouts of ≥10 min, 131 min per week (95% CI = 125, 137) of MVPA, and 7753 daily steps (95% CI = 7582, 7924). Proportion meta-analyses provided high quality evidence that 13% (95% CI = 7, 20) completed ≥150 min per week of MVPA in bouts of ≥10 min, low quality evidence that 41% (95% CI = 23, 61) completed ≥150 min per week of MVPA in absence of bouts, moderate quality evidence that 19% (95% CI = 8, 33) completed ≥10,000 steps per day, and low quality evidence that 48% (95% CI = 31, 65) completed ≥7000 steps per day. For hip osteoarthritis, 11 studies involving 325 participants averaged 160 min per week (95% CI = 114, 216) of MVPA when measured in bouts of ≥10 min, 189 min per week (95% CI = 166, 212) of MVPA, and 8174 daily steps (95% CI = 7670, 8678). Proportion meta-analyses provided low quality evidence that 58% (95% CI = 18, 92) completed ≥150 min per week of MVPA in absence of bouts, low quality evidence that 30% (95% CI = 13, 50) completed ≥10,000 steps per day, and low quality evidence that 60% (95% CI = 47, 73) completed ≥7000 steps per day. Conclusion A small to moderate proportion of people with knee and hip osteoarthritis met physical activity guidelines and recommended daily steps. Future research should establish the effects of increasing physical activity in this population to meet the current physical activity guidelines.

We investigated the biomechanical changes that occur in the lower limb following total knee arthroplasty (TKA). Lower limb joint kinematics and kinetics were evaluated in 32 patients before and 12 months following TKA and 28 age-matched controls. Analysis of variance with Bonferroni-adjusted post-hoc tests showed no significant changes in knee joint kinematics and kinetics following TKA despite significant improvements in pain and function. Significant increases in peak ankle plantarflexion and dorsiflexion moments and ankle power generation were observed which may be a compensatory response to impaired knee function to allow sufficient power generation for propulsion. Differences in knee gait parameters may arise as a result of the presence of osteoarthritis and mechanical changes associated with TKA as well as retention of the pre-surgery gait pattern.

Objective Patients with knee osteoarthritis (OA) are characterized by increased muscle inflammation and altered gait. We investigated the association between proinflammatory mediators in the vastus lateralis and physical function and gait in patients with knee OA. Methods Nineteen patients with knee OA underwent gait analysis, assessment of self-reported pain and physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), and a muscle biopsy that was taken during their knee replacement surgery. Muscle was analyzed for cellular protein inflammatory mediators, interleukin-6, monocyte chemotactic protein 1 (MCP-1), p65 NF-κB, signal transducer and activator of transcription 3 (STAT-3), and JNK-1. Sagittal plane knee function, including early stance knee range of motion (ROM) and knee sagittal plane impulse, was measured using a motion analysis system. Pearson's correlation was used to assess relationships between selected variables. Results Significant positive correlations were found between MCP-1 and self-perceived stiffness, physical function, and the total WOMAC score (P < 0.05). MCP-1 was also negatively correlated with early stance knee ROM (r = −0.52, P = 0.023). Reduced velocity was associated with elevated levels of p65 NF-κB and STAT-3 (P < 0.05). Knee sagittal plane impulse was negatively correlated with JNK-1 (P = 0.02), indicating reduction in knee impulse with an increased level of JNK-1. Conclusion Increased levels of several proinflammatory mediators were correlated with altered knee function during walking as well as greater physical disability and slower gait velocity. Identification of the cellular and molecular mechanisms associated with muscle inflammation is important to better understand the underlying mechanism responsible for altered gait and function in patients with knee OA.

An abnormal flexor moment pattern is often evident following total knee replacement (TKR) surgery. We investigated whether such a pattern at 12 months post-surgery could be predicted using biomechanical gait measures assessed before surgery and at 4 months post-surgery. Thirty two TKR patients were evaluated and classified as normal (biphasic pattern) or abnormal (flexor moment pattern) at each time point. Biomechanical parameters collected before surgery and at 4 months post-surgery were then explored for their ability to predict gait patterns at 12 months post-surgery. The gait pattern at 4 months was significantly associated with the 12 month post-surgery gait pattern, with over half of those with a flexor moment pattern at 4 months retaining this pattern at 12 months. Discriminant function analysis indicated that peak knee flexion during early stance, peak knee extension, and peak knee extension moment at 4 months post-surgery were independent predictors of the gait pattern at 12 months. Thus, an abnormal knee flexor moment pattern at 12 months post-surgery can be predicted by biomechanical analysis 4 months after surgery. Therefore, interventions aimed at improving active extension may need to be implemented early after surgery to restore a normal gait pattern.

Increased inflammation and pain are inseparable parts of knee osteoarthritis (OA) that may lead to disuse of the affected limb. The aim of this study was to examine the effects of knee OA on inflammation- and atrophy-related genes and proteins in the vastus lateralis muscle of patients with knee OA. Methods Nineteen patients with knee OA and 14 asymptomatic control subjects matched for age and body mass index underwent strength measurements and a muscle biopsy. Muscle was analyzed for the total cellular protein of inflammatory kinases (p65 NF-κB, JNK1/2, STAT-3, and suppressor of cytokine signaling 3 [SOCS-3]) and inflammatory intracellular molecules (interleukin-6 [IL-6], IL-8, monocyte chemoattractant protein 1 [MCP-1], tumor necrosis factor [TNF], IL-1β, and atrogin-1). Results Knee OA resulted in greater levels of IL-6 protein (34%; P = 0.002). The levels of inflammatory kinases, including STAT-3 (187%; P = 0.002), p65 NF-κB (156%; P = 0.002), and JNK1 (179%; P = 0.027), were also elevated. Furthermore, elevated expression of gene transcripts encoding MCP-1 (28%; P = 0.023), TNF (85%; P < 0.001), and SOCS-3 (38%; P = 0.055) was observed in patients with knee OA compared with control subjects. Patients with knee OA had reduced muscle strength compared with control subjects (mean ± SEM 84.7 ± 8.7 versus 143.1 ± 20.8 Nm; P = 0.005). Negative correlations were observed between muscle strength and MCP-1 protein abundance (r = −0.37 [P = 0.042]) and the gene expression of TNF and atrogin-1 messenger RNA (r = −0.46 [P = 0.012] and r = −0.36 [P = 0.040], respectively). Conclusion Gene expression and the protein abundance of numerous muscle markers of inflammation and atrophy were elevated in patients with knee OA, and the increase in muscle inflammation was associated with a reduction in muscle strength. Given the role inflammation markers may play in muscle strength and atrophy, further studies are needed to investigate the effect of exercise intervention on skeletal muscle inflammation.

Knee pain and disability can persist following knee replacement surgery which may place patients at increased risk of falls. This study investigated the falls risk and the occurrence of falls of people with knee osteoarthritis (OA) before and at 12 months following knee replacement surgery. Thirty-five patients with knee OA were tested prior to undergoing knee replacement surgery and at 12 months following surgery using the short form Physiological Profile Assessment, which incorporates tests of vision, lower limb proprioception, knee extension strength, reaction time and postural sway. Physical activity, number of falls, fear of falling, pain, disability and health-related quality of life were also assessed. No significant differences were found between the number of falls pre- and post-surgery (n.s.), with 48.5 and 40% reporting at least one fall in the 12 months before and following the surgery, respectively. Improvements in knee strength, reaction time and fear of falling were evident following surgery, with no improvement in lower limb proprioception. Self-reported pain, function and stiffness were significantly improved, but health-related quality of life deteriorated following the surgery. The number of falls experienced following knee replacement surgery remained relatively high, which may be attributed to the persistence of impaired lower limb proprioception. Although knee replacement surgery improves function and alleviates pain, people who undergo this procedure may need to engage in rehabilitation following the surgery to reduce the risk of falling. Therapeutic study investigating the result of treatment on patient outcomes, Level IV.

Background Foot posture has long been considered to contribute to the development of lower limb musculoskeletal conditions as it may alter the mechanical alignment and dynamic function of the lower limb. This study compared foot posture in people with and without medial compartment knee osteoarthritis (OA) using a range of clinical foot measures. The reliability of the foot measures was also assessed. Methods The foot posture of 32 patients with clinically and radiographically-confirmed OA predominantly in the medial compartment of the knee and 28 asymptomatic age-matched healthy controls was investigated using the foot posture index (FPI), vertical navicular height and drop, and the arch index. Independent t tests and effect size (Cohen's d) were used to investigate the differences between the groups in the foot posture measurements. Results Significant differences were found between the control and the knee OA groups in relation to the FPI (1.35 ± 1.43 vs. 2.46 ± 2.18, p = 0.02; d = 0.61, medium effect size), navicular drop (0.02 ± 0.01 vs. 0.03 ± 0.01, p = 0.01; d = 1.02, large effect size) and the arch index (0.22 ± 0.04 vs. 0.26 ± 0.04, p = 0.04; d = 1.02, large effect size). No significant difference was found for vertical navicular height (0.24 ± 0.03 vs. 0.23 ± 0.03, p = 0.54; d = 0.04, negligible effect size). Conclusion People with medial compartment knee OA exhibit a more pronated foot type compared to controls. It is therefore recommended that the assessment of patients with knee OA in clinical practice should include simple foot measures, and that the potential influence of foot structure and function on the efficacy of foot orthoses in the management of medial compartment knee OA be further investigated.

Knee osteoarthritis (OA) can lead to pain and disability in the older population. Excessive loading has been suggested to contribute to the development of knee OA. In this paper, we investigated the frequency components in accelerometric signals of the tibia in the anterior-posterior (AP), medial-lateral (ML) and vertical (Vert) directions during walking between people with severe knee OA and asymptomatic control group. The Fast Fourier Transform (FFT) was applied to the tibia accelerations in the three directions for 3 trials. The FFT decomposes the acceleration signal into a series of signals at different frequencies to investigate the frequency components (harmonics) in a signal where the power spectrum graphs provide quantitative information of signal composition. The frequency components in the AP and ML accelerations appear at similar frequencies for both healthy and knee OA subjects. Frequency components in the vertical acceleration, however, were found to have larger frequency components in the higher frequencies (>5 Hz) for the knee OA subjects compared to the healthy group. The differences in power peaks corresponding to higher harmonics (>6 Hz) between the groups may indicate instability and altered attenuation of the impact during walking for people with knee OA. Further work, should be directed on investigating the position of occurrence of the high frequency during the gait cycle and understanding the biomechanical mechanism responsible for these differences.

Knee osteoarthritis (OA) is one of the leading causes of disability among the elderly which, depending on severity, may require surgical intervention. Knee replacement surgery provides pain relief and improves physical function including gait. However gait dysfunction such as altered spatio-temporal measures may persist after the surgery. In this paper, we investigated the application of support vector machines (SVM) to classify gait patterns indicative of knee OA before surgery based on 12 spatio-temporal gait parameters and investigated whether SVMs could be used to predict gait improvement 2 and 12 months following knee replacement surgery. Test results for the pre-operative data indicated that the SVM could successfully identify individuals with OA gait from the healthy using all of the spatio-temporal parameters with a maximum leave one out accuracy of 100% for the training set and 88.89% for the test set. Findings indicated that three patients still had altered gait patterns 2 months post-knee replacement surgery, but all individuals showed improvement in gait 12 months following surgery. Consequently, the SVM detected improvement in gait function due to surgical intervention at 2 and 12 months following knee replacement which coincided with clinical assessment of the knee. This suggests that spatio-temporal parameters contain important discriminative information which may be used for the identification of pathological gait using an SVM classifier.

To examine the physical function, gait, and quality of life of patients after total hip replacement (THR) randomly assigned to either a targeted home- or center-based exercise program.Randomized controlled trial.Rehabilitation research center in Australia.Twenty-three patients with unilateral THR were randomly assigned to a supervised center-based exercise group (n=11) or an unsupervised home-based exercise group (n=12).The center-based group completed an 8-week targeted exercise program while under the direct supervision of a physiotherapist. After initial instruction, the home-based group completed the 8-week targeted exercise program at home without further supervision.Quality of life, physical function, and spatiotemporal measures of gait.No significant interaction (group by time) or main effects of grouping were found. Within each group, quality of life, and stair climbing improved significantly (P.05) as did Timed UpGo test and 6-minute walk test performances (P.05). Walking speed increased by 16 cm/s (P.01), cadence by 8 steps/min (P.05), step length by 4.7 cm (P.05), and double-support time reduced by a factor of 16%. Step length symmetry showed significant improvement (P.05) over time. Step length differential between the affected and unaffected limbs reduced from 4.0 to 2.7 cm.The targeted strengthening program was effective for both the home- and center-based groups. No group differences were found in the majority of the outcome measures. This finding is important because it shows that THR patients can achieve significant improvements through a targeted strengthening program delivered at a center or at home.

Knee pathologies such as patellofemoral pain syndrome (PFPS) and knee osteoarthritis (OA) can lead to pain and disability. PFPS limits mobility and potentially leads to knee osteoarthritis. A common treatment for knee OA is joint replacement surgery. In this paper, we investigated the application of multiclass support vector machines (SVM) to classify gait patterns between three knee pathology groups using ground reaction force (GRF) data. Results indicate that the multiclass SVM could identify the different knee pathologies with a maximum leave one out (LOO) accuracy of 78%-88% on the testing set. When feature selection was applied, the accuracy improved to 85%-92% and accuracy on the test set improved from 37% to 62%. The SVM detected 7 and 8 GRF features related to the peak GRFs and their relative timing as being sensitive to distinguish between patients with knee replacement and both knee OA and PFPS, respectively. Only 2 features (peak anterior GRF and time to heel strike transient) were required to discriminate knee OA from PFPS group. The SVM classifier was able to effectively recognize gait parameters that were altered due to the various knee pathology conditions. This suggests that GRF information is indicative of abnormal joint loading and can be detected using the multiclass SVM.

s / Osteoarthritis and Cartilage 21 (2013) S63–S312 S219 this is due to pain causing loss of muscle strength in knee OA, rather than loss of muscle strength causing structural progression of knee OA to higher KL grades. 413 IMPAIRED MUSCLE FUNCTION IN A MOUSE SURGICAL MODEL OF OSTEOARTHRITIS C. van der Poel y, P. Levinger z, B.A. Tonkin x, I. Levinger z,k, N.C. Walsh; x. yDept. of Human BioSci.s, La Trobe Univ., Melbourne, Australia; z Inst. of Sport, Exercise & Active Living, Victoria Univ., Melbourne, Australia; x St Vincent's Inst. of Med. Res., Melbourne, Australia; k Sch. of Sport and Exercise Sci., Victoria Univ., Melbourne, Australia Purpose: Osteoarthritis (OA) is typically characterised by progressive loss of articular cartilage and aberrant bone formation. However, in knee OA in particular, loss of muscle mass, strength and function is also common and this contributes to impaired quality of life through deterioration of functional capacity. Our previous studies in knee OA patients have shown that reduced muscle strength and altered walking pattern is associated with increased expression of pro-inflammatory cytokines and signalling molecules. It is not clear if the loss of muscle mass and strength in knee OA occurs as a result of reduced limb use, or if the muscle itself is a direct target of the OA degenerative processes. In order to better understand the relationship between OA and muscle function, we examined the changes in muscle function during the onset and progression of OA in a mouse surgical model of OA (destabilisation of the medial meniscus, DMM-OA) Methods: Male C57BL/6 mice underwent DMM or sham surgery on the right knee only. Tibialis anterior (TA) muscle function was assessed in situ at 1, 4 and 8 weeks post surgery (n 1⁄4 6 sham and 6 DMM-OA mice per timepoint). Parameters measured : tetanic forces absolute force (Po) and specific force (sPo, normalized to muscle mass); twitch force measurements twitch force production (Pt), time to peak (TPT) and time taken to relax to 50% of peak twitch force (1/2RT). Importantly, the TA muscle is not impacted directly by the surgical procedure. Joint damage and synovial inflammation were assessed by histology. Statistics: Multivariate analysis of variance (MANOVA) with Bonferroni correction was used to examine the differences within groups for the 3 time points. Results: DMM surgery results in destabilization of the knee joint leading to increased loading within the medial compartment of the knee joint. By 4 weeks post-surgery, proteoglycan loss, subchondral bone accrual and osteophyte formation are evident with significant cartilage erosion present at 8 weeks post surgery. Inflammation of the synovial lining due to surgery subsides in both the sham and DMM-OA knee joints by 4 weeks post surgery, but a thickened synovial lining layer remains within DMM-OA joints. At 1 week post surgery, there was no difference in either the tetanic or twitch force parameters between the DMM-OA and SHAM TAmuscle. However both DMM-OA and SHAM TA muscles showed improvement in their tetanic and twitch force parameters with time suggesting an effect of the surgery itself on muscle function. The tetanic parameters absolute force (Po) and specific force (sPo), were reduced in DMM-OA muscle compared to sham muscle at both 4 weeks and 8 weeks post surgery (P

Chronic musculoskeletal conditions in the lower extremities, particularly arthritis, and the chronic pain associated with them, are independent risk factors for falls, with approximately 50% of people with arthritis reporting one or more falls. Despite this, few studies have specifically addressed balance dysfunction, falls risk and falls incidence in people with arthritis. This review aimed to identify potential factors contributing to the increased risk of falls in people with lower limb osteoarthritis or rheumatoid arthritis and to summarise the evidence base for effective exercise interventions targeted to reduce their risk of falls. A systematic search of the literature was conducted in February 2010 and included the following databases: MEDLINE (Ovid), EMBASE, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine, Cochrane Library and PsycINFO. Only three studies that investigated exercise programmes for people with lower limb arthritis met all inclusion criteria, but none used falls as an outcome measure. To broaden the review, systematic reviews that assessed the effectiveness of exercise interventions for fall prevention in older people were also included. The presence of any form of lower limb arthritis and the associated consequences including pain, balance impairment, reduced muscle strength and reduced function are all associated with increased risk of falling. Due to the link between musculoskeletal pain and the increased risk of falls, further research needs to investigate which type of exercise programme will be effective in reducing the risk of falls in populations with arthritis in the lower limbs.

Background Dynamic joint loading, particularly the external knee adduction moment (KAM), is an important surrogate measure for the medio-lateral distribution of force across the knee joint in people with knee osteoarthritis (OA). Foot motion may alter the load on the medial tibiofemoral joint and hence affect the KAM. Therefore, this study aimed to investigate the relationship between tibia, rearfoot and forefoot motion in the frontal and transverse planes and the KAM in people with medial compartment knee OA. Method Motion of the knee, tibia, rearfoot and forefoot and knee moments were evaluated in 32 patients with clinically and radiographically-confirmed OA, predominantly in the medial compartment. Pearson’s correlation coefficient was used to investigate the association between peak values of tibia, rearfoot and forefoot motion in the frontal and transverse planes and 1st peak KAM, 2nd peak KAM, and the knee adduction angular impulse (KAAI). Results Lateral tilt of the tibia was significantly associated with increased 1st peak KAM (r = 0.60, p

Knee osteoarthritis (OA) is one of the leading causes of disability among the elderly which, depending on severity, may require surgical intervention. Knee replacement surgery provides pain relief and improves physical function including gait. Gait dysfunction such as altered spatio-temporal measures and gait asymmetry both pre- and post-surgery, however, may still persist after the surgery. In this paper, we investigated the application of support vector machines (SVM) to classify gait patterns pertaining to knee OA before surgery based on spatio-temporal gait parameters and to investigate whether SVM can assess gait improvement at 2 months following knee replacement surgery. Test results indicate that the SVM can identify the OA gait from the healthy ones with a max leave one out (LOO) accuracy of 94.2%. When feature selection technique was applied, the accuracy improved to 97.1% using only 2 symmetry index features. Further, the post surgery test results by the SVM indicated 4 patients still had altered gait. This suggests that subject gait symmetry should be monitored closely after surgery to assess treatment outcomes and recovery.