Prevalence of significant knee pain among older Americans: results from the Third National Health and Nutrition Examination Survey

Ten-year follow-up of a total knee prosthesis combining multi-radius, ultra-congruency, posterior-stabilization and mobile-bearing insert shows long-lasting clinically relevant improvements in pain, stiffness, function and stability

PURPOSE

There is a paucity of data available on total knee prostheses combining dual-radius, ultra-congruency, posterior-stabilization and mobile-bearing insert. This prospective cohort study aimed to assess the clinical evolution of the FIRST^® prosthesis (Symbios Orthopédie, Yverdon, CH), the earliest prosthesis with this particular design. It was hypothesized that the primary outcomes, evaluating pain, stiffness, function and stability, would improve following arthroplasty and remain improved during the follow-up period of 10 years.

METHODS

All patients programmed for a total knee arthroplasty using a FIRST^® prosthesis at our university hospital between 2006 and 2008 were invited to participate. Study knees were evaluated pre-operatively as well as one, five and ten years post-operatively. Patients filled out questionnaires at each evaluation point and had a radiographic assessment at the five-year and ten-year follow-ups. Primary outcomes were the total, pain, stiffness and function measures of the Western Ontario and McMaster Universities Osteoarthritis questionnaire (WOMAC) and the knee and function measures of the Knee Society Score (KSS). Friedman and Wilcoxon's rank-sum tests were used to compare measures across time points.

RESULTS

Hundred and twenty four prostheses were included (baseline demographics: 69.9 ± 8.3 years old, 28.1 ± 4.3 kg/m², 54% male) and 68 could be followed during ten years. Five prostheses underwent a revision. All other prostheses lost at follow-up were lost for reasons unrelated to the prosthesis. All primary measures reported statistically and clinically significant improvements between baseline and the three follow-up evaluations. Statistically significant improvements at the three follow-up evaluations were also observed for most secondary measures. There was no implant loosening. At ten-year follow-up, radiolucent lines were observed in 2.9% femoral implants and 1.5% tibial implants.

CONCLUSION

The positive results observed in all domains of assessment and the small revision rate demonstrated an effective functioning of the FIRST^® prosthesis during the ten-year follow-up period. The results, globally similar to those previously published for other prosthesis designs, encourage the development of assistive methods to select the most appropriate designs on an individual basis.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Computational biomechanics of human knee joint in stair ascent: Muscle-ligament-contact forces and comparison with level walking

About a third of knee joint disorders originate from the patellofemoral (PF) site that makes stair ascent a difficult activity for patients. A detailed finite element model of the knee joint is coupled to a lower extremity musculoskeletal model to simulate the stance phase of stair ascent. It is driven by the mean of measurements on the hip-knee-ankle moments-angles as well as ground reaction forces reported in healthy individuals. Predicted muscle activities compare well to the recorded electromyography data. Peak forces in quadriceps (3.87 BW, body weight, at 20% instance in our 607 N subject), medial hamstrings (0.77 BW at 20%), and gastrocnemii (1.21 BW at 80%) are estimated. Due to much greater flexion angles-moments in the first half of stance, large PF contact forces (peak of 3.1 BW at 20% stance) and stresses (peak of 4.83 MPa at 20% stance) are estimated that exceed their peaks in level walking by fourfold and twofold, respectively. Compared with level walking, ACL forces diminish in the first half of stance but substantially increase later in the second half (peak of 0.76 BW at 75% stance). Under nearly similar contact forces at 20% of stance, the contact stress on the tibiofemoral (TF) medial plateau reaches a peak (9.68 MPa) twice that on the PF joint suggesting the vulnerability of both joints. Compared with walking, stair ascent increases peak ACL force and both peak TF and PF contact stresses. Reductions in the knee flexion moment and/or angle appear as a viable strategy to mitigate internal loads and pain.

Gender Differences in Seeking Health Care and Postintervention Pain Outcomes in Foot and Ankle Orthopedic Patients

Background:

Materials and Methods:

Results:

Conclusions:

Treatment of Patellofemoral Pain Syndrome with Dielectric Radiofrequency Diathermy: A Preliminary Single-Group Study with Six-Month Follow-Up

Background and Objectives: Notwithstanding patellofemoral pain syndrome (PFPS) being one of the most common causes of pain in the front of the knee in outpatients, few studies have shown the effects of radiofrequency on knee pain and function in this population. The aim of the present study was to determine whether outpatients diagnosed with PFPS obtained improvement in pain and function after treatment by dynamic application of monopolar dielectric diathermy by emission of radiofrequency (MDR). Materials and Methods: An experimental study was conducted with 27 subjects with PFPS. Subjects were treated with 10 sessions of MDR in dynamic application. The visual analogue scale (VAS), the Kujala scale, the DN4 questionnaire, the lower extremity function scale (LEFS), the range of movement (ROM) in knee flexion and extension and the daily drug intake were measured pre- and post-intervention and at the time of the follow-up (six months). Results: Statistically significant differences were found in pain perception (VAS: F_1,26 = 92.43, p < 0.000, ŋ² = 0.78 and DN4: F_1.26 = 124.15, p < 0.000, ŋ² = 0.82), as well as improvements in functionality (LEFS: F_1.26 = 72.42, p < 0.000, ŋ² = 0.74 and Kujala: F_1.26 = 40.37, p < 0.000, ŋ² = 0.61]) and in ROM (Flexion: F_1.26 = 63.15, p < 0.000, ŋ² = 0.71). No statistically significant changes in drug intake were found. Conclusions: The present study shows that the dynamic application of MDR seems effective in reducing pain and increasing functionality and knee flexion in patients with PFPS, after a follow-up of six months.

Effects of technology-supported exercise programs on the knee pain, physical function, and quality of life of individuals with knee osteoarthritis and/or chronic knee pain: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The study sought to examine the effects of technology-supported exercise programs on the knee pain, physical function, and quality of life of individuals with knee osteoarthritis and/or chronic knee pain by a systematic review and meta-analysis of randomized controlled trials.

MATERIALS AND METHODS

We searched MEDLINE, EMBASE, CINAHL Plus, and the Cochrane Library from database inception to August 2020. A meta-analysis and subgroup analyses, stratified by technology type and program feature, were conducted.

RESULTS

Twelve randomized controlled trials were reviewed, all of which implemented the programs for 4 weeks to 6 months. Telephone, Web, mobile app, computer, and virtual reality were used to deliver the programs. The meta-analysis showed that these programs were associated with significant improvements in knee pain (standardized mean difference [SMD] = -0.29; 95% confidence interval [CI], -0.48 to -0.10; P = .003) and quality of life (SMD = 0.25; 95% CI, 0.04 to 0.46; P = .02) but not with significant improvement in physical function (SMD = 0.22; 95% CI, 0 to 0.43; P = .053). Subgroup analyses showed that some technology types and program features were suggestive of potential benefits.

CONCLUSIONS

Using technology to deliver the exercise programs appears to offer benefits. The technology types and program features that were associated with health values have been identified, based on which suggestions are discussed for the further research and development of such programs.

Association of trajectory of body mass index with knee pain risk in Japanese middle-aged women in a prospective cohort study: the Japan Nurses' Health Study

OBJECTIVES

To investigate whether body mass index (BMI) trajectory, lifestyle and reproductive factors are associated with knee pain risk among middle-aged women.

DESIGN

Prospective study of the Japan Nurses' Health Study (JNHS).

SETTING

The JNHS investigates the health of female nurses in Japan. Biennial follow-up questionnaires are mailed to the participants.

PARTICIPANTS

The 7434 women aged over 40 years who responded to the 10-year self-administered follow-up questionnaire.

PRIMARY OUTCOME MEASURE

Self-reported knee pain at the 10-year follow-up was the primary outcome. We analysed BMI (normal or overweight) trajectory data from a baseline survey to the 10-year follow-up survey using group-based trajectory modelling. Exposure measurements were BMI trajectory, BMI at age 18 years, lifestyle variables and reproductive history.

RESULTS

BMI trajectories from baseline to the 10-year follow-up were divided into four groups: remained normal, remained overweight, gained weight or lost weight. At the 10-year follow-up, 1281 women (17.2%) reported knee pain. Multivariable logistic regression analysis revealed that compared with the remained normal group, multivariable-adjusted ORs (95% CI) of knee pain were 1.93 (1.60 to 2.33) for the remained overweight group, 1.60 (1.23 to 2.08) for the gained weight group and 1.40 (0.88 to 2.21) for the lost weight group. The attributable risk percent (95% CI) of the remained overweight group was 48.1% (37.3% to 57.0%) compared with the reference group of remained normal. Alcohol intake at baseline was significantly associated with knee pain.

CONCLUSIONS

The lost weight group had a lower risk than the remained overweight group and the gained weight group and did not carry statistically significant risks for knee pain. Weight reduction and maintaining a normal BMI in middle age was important for preventing knee pain in women.

A Comparative Study of Botulinum Toxin: A with Triamcinolone Compared to Triamcinolone alone in the treatment of Osteoarthritis of Knee

Introduction:

This study compares the efficacy in terms of pain relief and complications of intra-articular Botulinum toxin-A (BoNT-A) with intra-articular Triamcinolone versus Triamcinolone alone in the treatment of osteoarthritic knee pain of severe grade. If effective, BoNT-A may help in reducing the long term adverse effects due to prolonged analgesic consumption and reduce/delay requirement of knee replacement surgeries.

Materials and Methods:

In this prospective study, 30 patients of either sex, aged between 40 to 60 years with physical status ASA classes I or II suffering from knee joint osteoarthritis with knee pain and functional impairment were divided into 2 groups: The OA patients which received Botulinum toxin-A with Triamcinolone (Group A) & OA patients which received only Triamcinolone (Group B). Only patients with advanced OA of the knee; radiographically verified with a Joint space <2 mm were included. The efficacy of pain relief in the 2 groups were compared using Visual analog score (VAS) and Oxford knee Score and followed upto 6 months.

Results and Conclusions:

On comparing the VAS Score during the follow up period, there was a significant difference between groups A and B upto 3 months. During post treatment follow up, there was significant difference in pain relief as measured by the Oxford Knee score from 4 weeks to 6 months, where Group A patients fared much better in terms of pain relief than group B with a highly significant value of P =<0.001 during the time period of 6 weeks to 6 months. The study shows that the use intra-articular Botulinum toxin-A with steroid is far superior to intra-articular steroid alone in terms of pain relief as well as functional outcome.

Hydroethanolic extract of Psidium guajava leaf for induced osteoarthritis using a guinea pig model

We investigated the therapeutic effects of an extract of Psidium guajava (guava) leaf on experimentally induced osteoarthritis in guinea pig. The left knee of 30 male guinea pigs was anesthetized and the cranial cruciate ligament was severed. The animals were followed for 8 weeks until osteoarthritis was confirmed by radiography and histopathology. Animals were divided randomly into five groups; group 1, the ligament was severed and untreated; group 2, the ligament was severed and treated with piascledine, an extract of soybean and avocado; group 3, the ligament was severed and treated with 200 mg/kg hydroethanolic extract of guava; group 4, the ligament was severed and treated with 400 mg/kg hydroethanolic extract of guava; and group 5, control animals without surgery or extracts. Radiological and histopathological evaluations after 8 weeks showed reduced severity of osteoarthritis in the piascledine treatment group compared to group 1. The guava extract also reduce the severity of osteoarthritis compared to controls. Histopathological examination of treatment and control groups showed that treatment the guava extract improved lesions significantly. Hydroethanolic extracts of guava leaf appears to prevent osteoarthritis by inhibition of free radical formation in the knee joint.

Translating Comprehensive Conservative Care for Chronic Knee Pain Into a Digital Care Pathway: 12-Week and 6-Month Outcomes for the Hinge Health Program

Background

Chronic knee pain (CKP) affects a large number of adults, many of whom do not receive best-practice care and are at high risk for unnecessary surgery.

Objective

The aim of this study was to investigate the effect of the Hinge Health 12-week digital care program (DCP) for CKP on knee pain and function, with secondary outcomes of surgery interest and satisfaction, at 12 weeks and 6 months after starting the program.

Methods

Individuals with CKP were recruited onto the 12-week program, comprising sensor-guided physical exercises, weekly education, activity tracking, and psychosocial support such as personal coaching and cognitive behavioral therapy (CBT). We used a single-arm design with assessment of outcomes at baseline, 12 weeks, and 6 months after starting the program. We used a linear mixed effects model with Tukey contrasts to compare timepoints and report intention-to-treat statistics with last observation carried forward.

Results

The cohort consisted of 41 individuals (32 female, mean age 52 years, SD 9 years). Between baseline and week 12, participants reported clinically significant improvements in the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain and Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) function scales of 16 points (95% CI 12-21, P<.001) and 10 points (95% CI 6-14, P<.001), respectively. Significant reductions of 57% (mean difference 30, 95% CI 21-38, P<.001) and 51% (mean difference 25, 95% CI 16-33, P<.001) in visual analog scale (VAS) knee pain and stiffness, respectively, were observed at 12 weeks, as well as a 67% reduction in surgery interest (mean reduction 2.3 out of 10, 95% CI 1.5-3.1, P<.001). Average satisfaction at week 12 was 9.2 out of 10. Critically, all improvements were maintained at 6 months at similar or greater magnitude.

Conclusions

Participants on the Hinge Health DCP for CKP showed substantial clinical improvements that were maintained 6 months after enrolling in the program. This shows that DCPs carry strong potential to deliver evidence-based, cost-effective care to those suffering from CKP.

Relationship between biological factors and catastrophizing and clinical outcomes for female patients with knee osteoarthritis

AIM

To investigate the correlations between clinical outcomes and biopsychological variables in female patients with knee osteoarthritis (OA).

METHODS

Seventy-seven patients with symptomatic knee OA were enrolled in this study. We investigated the age, body mass index (BMI), pain catastrophizing scale (PCS) and radiographic severity of bilateral knees using a Kellgren-Lawrence (K-L) grading system of the subjects. Subsequently, a multiple linear regression was conducted to determine which variables best correlated with main outcomes of knee OA, which were pain severity, moving capacity by measuring timed-up-and-go test and Japanese Knee Osteoarthritis Measure (JKOM).

RESULTS

We found that the significant contributor to pain severity was PCS (β = 0.555) and BMI (β = 0.239), to moving capacity was K-L grade (β = 0.520) and to PCS (β = 0.313), and to a JKOM score was PCS (β = 0.485) and K-L grade (β = 0.421), respectively.

CONCLUSION

The results suggest that pain catastrophizing as well as biological factors were associated with clinical outcomes in female patients with knee OA, irrespective of radiographic severity.

The Use of MRI in Evaluating Knee Pain in Patients Aged 40 Years and Older

INTRODUCTION

The use of MRI is increasing when evaluating patients with knee pain because it is highly sensitive for detecting intra-articular pathology. However, such changes can be associated with degenerative joint disease, which may be demonstrated with weight-bearing radiographs. The purpose of this study was to determine how often MRI was obtained before orthopaedic referral in patients aged ≥40 years with knee pain, how often weight-bearing radiographs were obtained before MRI, and whether such imaging influenced treatment recommendations.

METHODS

In a study of 599 new patients, participating physicians documented the presence of a prereferral MRI and/or plain radiographic studies, the results of weight-bearing radiographs, treatment recommendations, and the impact of any prereferral imaging.

RESULTS

Prereferral use of MRI occurred in 130 patients (22%). Of these patients, plain radiographic studies were obtained for 58% before MRI and 13% had weight-bearing radiographs. Ultimately, 17% had weight-bearing radiographs that demonstrated >50% loss of joint space. Forty-eight percent of prereferral MRIs did not contribute to treatment recommendations. In patients with >50% loss of joint space, MRI was considered unnecessary in 95% of the cases.

DISCUSSION

Many prereferral MRIs do not contribute to clinical decision making. Weight-bearing radiographs can help identify those patients in whom MRI is unlikely to be helpful.

LEVEL OF EVIDENCE

Level III.

Vitamin D and the characteristics associated with risk for knee pain among Korean older adults: Findings from a nationally representative survey

AIM

To explore vitamin D and the risk factors associated with knee pain in a representative population of Korean older adults METHODS: Data were analyzed from the Korean National Health and Nutrition Examination Survey (2010-2013). A total of 3874 participants (1728 men, 2146 women) aged 65 years and older who had a measured serum 25-hydroxyvitamin D level were evaluated. Multivariate logistic regression was used to investigate the relationship between serum vitamin D and knee pain severity RESULTS: Sex, age, obesity, education, knee radiographic osteoarthritis, hip pain and back pain were associated with having knee pain. Also, the level of serum 25-hydroxyvitamin D was not significantly associated with knee pain severity. After controlling for confounding factors, the level of serum 25-hydroxyvitamin D was not significantly associated with knee pain, and severity levels of mild, moderate and severe.

CONCLUSIONS

The results show that the serum vitamin D did not have a significant effect on knee pain in older adults in Korea. Geriatr Gerontol Int 2017; 17: 1278-1285.

Prevalence of Self-Reported Arthritis Among Elders From Latin America and the Caribbean and Among Mexican Americans From the Southwestern United States

This study examines the prevalence of self-reported arthritis and arthritis symptoms and their relationship to functional limitations in elders from Latin America and the Caribbean and in Mexican Americans from the southwestern United States. This study includes 8,122 elderly aged 60 and older from seven Latin America and Caribbean countries and 2,580 noninstitutionalized Mexican Americans aged 65 or older residing in the southwestern United States. The estimated prevalence of self-reported arthritis ranged from 23.8% in Mexico City to 55.6% in Havana. The prevalence of self-reported pain among arthritic subjects across all countries ranged from 30.7% in older Mexican Americans to 83.7% in Santiago. Arthritis was independently associated with any Activities of Daily Living and any Instrumental Activities of Daily Living limitation across the eight countries after controlling for relevant factors. Self-reported arthritis and arthritis symptoms are highly prevalent among elders from Latin America and the Caribbean and older Mexican Americans and is a significant cause of disability in all studied populations.

Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain

Knee joint pain (KJP) is a cardinal symptom in knee pathologies, and quadriceps inhibition is commonly observed among KJP patients. Previously, KJP independently reduced quadriceps strength and activation. However, it remains unknown how disinhibitory transcutaneous electrical nerve stimulation (TENS) will affect inhibited quadriceps motor function. This study aimed at examining changes in quadriceps maximum voluntary contraction (MVC) and central activation ratio (CAR) before and after sensory TENS following experimental knee pain. Thirty healthy participants were assigned to either the TENS or placebo groups. All participants underwent three separate data collection sessions consisting of two saline infusions and one no infusion control in a crossover design. TENS or placebo treatment was administered to each group for 20 min. Quadriceps MVC and CAR were measured at baseline, infusion, treatment, and post-treatment. Perceived knee pain intensity was measured on a 100-mm visual analogue scale. Post-hoc analysis revealed that hypertonic saline infusion significantly reduced the quadriceps MVC and CAR compared with control sessions (P < 0.05). Sensory TENS, however, significantly restored inhibited quadriceps motor function compared with placebo treatment (P < 0.05). There was a negative correlation between changes in MVC and knee pain (r = 0.33, P < 0.001), and CAR and knee pain (r = 0.62, P < 0.001), respectively.

Knee Pain and a Prior Injury Are Associated with Increased Risk of a New Knee Injury: Data from the Osteoarthritis Initiative

OBJECTIVE

We explored whether knee pain or a history of knee injury were associated with a knee injury in the following 12 months.

METHODS

We conducted longitudinal knee-based analyses among knees in the Osteoarthritis Initiative. We included both knees of all participants who had at least 1 followup visit with complete data. Our first sets of exposures were knee pain (chronic knee symptoms and severity) at baseline, 12-month, 24-month, and 36-month visits. Another exposure was a history of injury that we defined as a self-reported injury at any time prior to baseline, 12-month, 24-month, or 36-month visit. The outcome was self-reported knee injury during the past year at 12-month, 24-month, 36-month, and 48-month visits. We evaluated the association between ipsilateral and contralateral knee pain or history of injury and a new knee injury within 12 months of the exposure using generalized linear mixed model for repeated binary outcomes.

RESULTS

A knee with reported chronic knee symptoms or ipsilateral or contralateral history of an injury was more likely to experience a new knee injury in the following 12 months than a knee without chronic knee symptoms (OR 1.84, 95% CI 1.57-2.16) or prior injury (prior ipsilateral knee injury: OR 1.81, 95% CI 1.56-2.09. Prior contralateral knee injury: OR 1.43, 95% CI 1.23-1.66).

CONCLUSION

Knee pain and a history of injury are associated with new knee injuries. It may be beneficial for individuals with knee pain or a history of injury to participate in injury prevention programs.

Patients with knee osteoarthritis undergoing total knee arthroplasty have a lower risk of subsequent severe cardiovascular events: propensity score and instrumental variable analysis

Objective

This population-based study investigated the subsequent cardiovascular risk of patients with knee osteoarthritis underwent total knee arthroplasty in Taiwan.

Materials and methods

This was a population-based follow-up study of 22931 patients diagnosed with knee osteoarthritis between 2008 and 2011. Each patient was followed for 3 years or until death. Treatment was dichotomized into conservative treatment and TKA. The association between TKA and cardiovascular disease (CVD) events was analyzed using propensity score analysis and instrumental variable analysis and two-stage least-squares regression model.

Results

Patients with knee osteoarthritis who underwent TKA had a lower 3-year cumulative risk of stroke and acute myocardial infarction (AMI). After adjusting for measured risk and confounding factors, propensity score showed a 0.56 fold (adjusted OR = 0.56; 95% CI, 0.51–0.61; p<0.001) risk for CVD in those with TKA. Use of instrumental variable analysis for adjusting measured and unmeasured factors and two-stage least squares regression model revealed that the average treatment effect of TKA was statistically associated with a decreased 7% risk of CVD events (95% CI, 0.2%–13.6%).

Conclusion

Our study revealed that patients with knee osteoarthritis who underwent TKA had a lower risk of suffering from a future severe cardiovascular event. This benefit may be attributed to an improvement in physical activity, reduction of psychosocial stress, and/or a decreased use of NSAIDs as a result of having undergone TKA.

Medial abrasion syndrome: a neglected cause of knee pain in middle and old age

Knee pain is a prevailing health problem of middle and old age. Medial plica-related medial abrasion syndrome (MAS), although a well-known cause of knee pain in younger individuals, has rarely been investigated in older individuals. This prospective study was conducted to investigate the prevalence and clinical manifestations of this syndrome as a cause of knee pain in middle and old age. The outcomes of arthroscopic treatment for this syndrome were also evaluated.A total of 232 knees of 169 patients >40 years of age (41-82, median: 63 years old) suffering from chronic knee pain were analyzed. The clinical diagnosis, predisposing factors, presenting symptoms, and physical signs were investigated. The sensitivity and specificity of each parameter of the clinical presentation for the diagnosis of MAS were evaluated after confirmation by arthroscopy. For patients with MAS, the roentgenographic and arthroscopic manifestations were investigated, and arthroscopic medial release (AMR) was performed. The outcomes were evaluated by the changes in the pain domain of the Knee Society scoring system and by patient satisfaction. The prevalence of medial plica was 95%, and osteoarthritis (OA) was the most common clinical diagnosis. Symptoms of pain and crepitus in motion and local tenderness during physical examination were the most sensitive parameters for the diagnosis. A history of a single knee injury combined with local tenderness and a palpable band found during physical examination were the most specific parameters for the diagnosis. The majority of patients suffering from this syndrome were successfully treated using AMR, yielding a satisfaction rate of 85.5% after a minimum of 3 years.MAS is a common cause of knee pain in middle and old age and can be effectively treated by AMR. Its concomitance with OA warrants further investigation.

Gender-specific outcome after implantation of low-contact-stress mobile-bearing total knee arthroplasty with a minimum follow-up of ten years

PURPOSE

The study aim was an analysis of gender-specific outcome differences after implantation of the low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) with a minimum follow-up of ten years.

METHODS

We retrospectively analysed 138 prostheses in 108 patients (82 women and 26 men) using our hospital database and a minimum follow-up of ten years (mean 14, range 11-23). Data was extracted with respect to quality of life, clinical outcome parameters [range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, visual analogue scale (VAS), Knee Society Score (KSS), and complications.

RESULTS

At follow-up, we observed no statistically significant differences in all outcome parameters between female and male patients after LCS TKA, except for VAS score, which revealed no clinical relevance due to the low difference (1.53 vs 1.03, p = 0.043).

CONCLUSIONS

Ten years after implantation of the LCS TKA, gender did not influence its beneficial outcome.

When it hurts, a positive attitude may help: association of positive affect with daily walking in knee osteoarthritis. Results from a multicenter longitudinal cohort study

OBJECTIVE

While depressive symptoms and knee pain are independently known to impede daily walking in older adults, it is unknown whether positive affect promotes daily walking. This study investigated this association among adults with knee osteoarthritis (OA) and examined whether knee pain modified this association.

METHODS

This study is a cross-sectional analysis of the Multicenter Osteoarthritis Study. We included 1,018 participants (mean ± SD age 63.1 ± 7.8 years, 60% women) who had radiographic knee OA and had worn a StepWatch monitor to record their number of steps per day. High and low positive affect and depressive symptoms were based on the Center for Epidemiologic Studies Depression Scale. Knee pain was categorized as present in respondents who reported pain on most days at both a clinic visit and a telephone screening.

RESULTS

Compared to respondents with low positive affect (27% of all respondents), those with high positive affect (63%) walked a similar number of steps per day, while those with depressive symptoms (10%) walked less (adjusted β -32.6 [95% confidence interval (95% CI) -458.9, 393.8] and -579.1 [95% CI -1,274.9, 116.7], respectively). There was a statistically significant interaction of positive affect by knee pain (P = 0.0045). Among the respondents with knee pain (39%), those with high positive affect walked significantly more steps per day (adjusted β 711.0 [95% CI 55.1, 1,366.9]) than those with low positive affect.

CONCLUSION

High positive affect was associated with more daily walking among adults with painful knee OA. Positive affect may be an important psychological factor to consider for promoting physical activity among people with painful knee OA.

Sex-related outcome differences after implantation of low-contact-stress mobile-bearing total knee arthroplasty

PURPOSE

The aim of the study was to investigate outcome differences between female and male patients after implantation of low-contact-stress (LCS) mobile-bearing total knee prostheses at a minimum follow-up of five years with respect to clinical and radiological parameters.

METHODS

We retrospectively analysed 128 prostheses in 126 patients (90 women and 34 men) using our hospital database. Data was extracted with respect to range of motion (ROM), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the Knee Society Score (KSS) and radiolucent lines on conventional X-rays.

RESULTS

At follow-up, we observed no significant differences between female and male patients after LCS total knee prostheses. Benefit after implantation of LCS total knee prostheses after five years of minimum follow-up was not significantly different between female and male patients in terms of clinical outcome or radiolucent lines.

CONCLUSIONS

We found no factors in favour of gender-specific total knee prostheses.

Association of vitamin D status with knee pain and radiographic knee osteoarthritis

OBJECTIVE

The objective of the present study was to explore the association of serum vitamin D concentration and polymorphism in the vitamin D receptor (VDR), with knee pain and radiographic knee osteoarthritis (OA) among men and women in a large population-based UK cohort study.

METHODS

Seven hundred and eighty-seven participants in the Hertfordshire Cohort Study (399 men, 388 women; mean age 65.6±2.7 years) underwent a questionnaire on knee pain and radiographic knee examination. This study examined the association of Fok1, Cdx2 and Apa1 polymorphism in the gene for the VDR and serum 25(OH)D concentration with knee pain and radiographic knee OA by a generalized estimating equations population averaged logistic regression analysis in the Hertfordshire Cohort Study.

RESULTS

There were no associations of Fok1, Cdx2 and Apa1 polymorphisms of the VDR with knee OA except for Aa for Apa1 compared with AA [Odds ratio (OR) 0.59, 95% confidence interval (CI) 0.36-0.95, P=0.031]. While, ff for Fok1 (OR 1.60, 95% CI 1.07-2.39, P=0.022) and AA for Cdx2 polymorphism (OR 2.21, 95% CI 1.07-4.56, P=0.032) was significantly associated with higher prevalence of knee pain compared with FF for Fok1 and GG for Cdx2, respectively. None of these are statistically significant after adjusting for the three polymorphisms tested. 25(OH)D level was not significantly associated with radiographic knee OA, while, low tertile of 25(OH)D level tended to be associated with knee pain compared with high tertile of 25(OH)D level.

CONCLUSION

The present cross-sectional study using a large-scale population from the Hertfordshire Cohort study indicated that vitamin D may be associated with pain rather than radiographic change, but the evidence for an association between vitamin D genetic variation and pain in knee OA is very weak in the present study. Further replication of our results will be required to elucidate the association of vitamin D and knee OA.

Psychological health impact on 2-year changes in pain and function in persons with knee pain: data from the Osteoarthritis Initiative

OBJECTIVE

We determined whether baseline depressive symptoms, knee-related confidence and general psychological distress influenced changes in pain and function during 2 years of follow-up.

DESIGN

We included persons in the Osteoarthritis Initiative (OAI) dataset with baseline pain of 1 or greater on a 0-10 scale in at least one knee and no knee or hip surgery during the 2-year follow-up (n=3407). The four outcome variables were repeated chair standing, 20 m walk and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Disability. Linear mixed effects models assessed the association of each mental health variable with the yearly change in each baseline adjusted outcome measure after controlling for covariates.

RESULTS

Depressive symptoms were significantly predictive of worsening in most outcomes. The magnitude of worsening predicted for each year was small. For example, the dichotomized WOMAC Pain model indicated that depressed persons experience more rapid worsening than non-depressed persons at an average rate of 0.59 WOMAC points per year (95% CI 0.176, 1.013, P=0.005). Similar significant but very small effects of depressive symptoms on other outcomes were observed. Knee confidence was not predictive of change. General psychological distress was predictive of change in 20-m walk and WOMAC Pain.

CONCLUSIONS

The most consistent psychological predictor of yearly worsening was baseline depressive symptoms. Although a statistically robust predictor of outcome, given that change was very small and highly dependent on baseline status, our results indicate that a considerable degree of persistent depressive symptoms would be required to have a meaningful effect on future self-reported outcome.

Examining sex and gender disparities in total joint arthroplasty

BACKGROUND

Total joint arthroplasty (TJA) is remarkably successful for treating osteoarthritis: most patients see substantial gains in function. However, there are considerable geographic, racial, and gender variations in the utilization of these procedures. The reasons for these differences are complex.

QUESTIONS/PURPOSES

We examined sex and gender disparities in TJA.

METHODS

Through Medline/PubMed searches, we identified 632 articles and from these selected 61 for our review. WHERE ARE WE NOW?: A number of factors might explain sex and gender disparities in TJA: underrepresentation in clinical trials, differences in willingness to undergo surgery, pain responses to underlying disease and treatment, patient-physician relationships, treatment preferences, provider-level factors such as physician-patient communication style, and system-level factors such as access to specialist care. Since women have a higher prevalence of arthritis and degenerative joint diseases and overall demand for these procedures will continue to grow, the need to understand why there is a gap in utilization based on gender is imperative. WHERE DO WE NEED TO GO?: Understanding what exactly is meant by "disparity" is essential because it is possible anatomic factors may have different impacts on utilization from cultural factors. Ideally, information about these factors should be integrated into the decision-making process so that patients and providers can make the most informed choice about whether or not to undergo the procedure. HOW DO WE GET THERE?: To better understand all of the potential reasons for how anatomic and cultural factors related to sex and gender might impact decision-making and overall utilization of TJA, more research focusing on these factors must be designed and carried out.

Frequency of Bone Marrow Lesions and Association with Pain Severity: Results from a Population-based Symptomatic Knee Cohort

Objective.

To evaluate the prevalence of bone marrow lesions (BML) and their association with pain severity in a population-based cohort of symptomatic early knee osteoarthritis (OA).

Methods.

Subjects with knee pain (n = 255), age 40–79 years, were evaluated by radiograph and magnetic resonance imaging (MRI) and classified into OA stages: no OA (NOA), preradiographic OA (PROA), and radiographic OA (ROA). BML were graded 0–3 (none, mild, moderate, severe) in 6 regions and defined as (1) BMLsum = the sum of 6 scores; and (2) BMLmax = the worst score at any region. Pain was assessed by the Western Ontario and McMaster Universities OA Index (WOMAC). Linear regression analysis was completed to assess the association of Total WOMAC Pain (primary outcome) versus BMLsum or BMLmax. Secondary outcomes were WOMAC Pain on Walking and WOMAC Pain on Climbing Stairs. All analyses were adjusted for age, sex, body mass index, OA stage, joint effusion, and meniscal damage.

Results.

BML were present in 11% of NOA, 38% of PROA, and 71% of ROA subjects (p < 0.001). No association was seen for BMLsum or BMLmax versus Total WOMAC Pain or Pain on Walking. However, BMLsum was associated with Pain on Climbing Stairs [regression coefficients (RC) = 0.09, 95% CI 0.00–0.18]. BMLmax was associated with Pain on Climbing Stairs, with the strongest association for severe BML (RC 0.60, 95% CI 0.04–1.17).

Conclusion.

BML were present in 38% of PROA and 71% of ROA subjects in this symptomatic knee cohort. BML were significantly associated with Pain on Climbing Stairs but not Total WOMAC or Pain on Walking.

Efficacy and safety of flavocoxid, a novel therapeutic, compared with naproxen: a randomized multicenter controlled trial in subjects with osteoarthritis of the knee

INTRODUCTION

Flavocoxid is a novel flavonoid-based "dual inhibitor" of the 5-lipoxygenase (5-LOX) enzyme and the cyclooxygenase (COX) enzymes. This study was designed to compare the effectiveness and safety of flavocoxid to naproxen in subjects with moderate to severe osteoarthritis (OA) of the knee.

METHODS

In this randomized, multicenter, double-blind study, 220 subjects were assigned to receive either flavocoxid (500 mg twice daily) or naproxen (500 mg twice daily) for 12 weeks. The trial was structured to show noninferiority of flavocoxid to naproxen. Primary outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subscales and a timed walk.

RESULTS

More than 90% of the subjects in both groups noted significant reduction in the signs and symptoms of knee OA. There were no statistically significant differences in efficacy between the flavocoxid and naproxen groups when the entire intent-to-treat population was analyzed. The flavocoxid group had significantly fewer upper gastrointestinal (UGI) and renal (edema) adverse events (AEs) as well as a strong trend toward fewer respiratory AEs.

CONCLUSION

Flavocoxid, a first-in-class flavonoid-based therapeutic that inhibits COX-1 and COX-2 as well as 5-LOX, was as effective as naproxen in managing the signs and symptoms of OA of the knee. Flavocoxid demonstrated better UGI, renal (edema), and respiratory safety profiles than naproxen.

In rural Tibet, the prevalence of lower limb pain, especially knee pain, is high: an observational study

QUESTION

What is the point prevalence and 12-month prevalence of lower limb musculoskeletal pain in rural Tibet? Does this differ with gender or age? What factors that could contribute to lower limb musculoskeletal pain are commonly present?

DESIGN

Observational study using an investigator-administered questionnaire and observation walks through villages.

PARTICIPANTS

499 people aged 15 years and over living in 19 rural villages of Shigatse Municipality, Tibet.

RESULTS

The point prevalence of lower limb musculoskeletal pain was 40% (95% CI 34 to 46) while the 12-month prevalence was 48% (95% CI 42 to 54). In particular, the point prevalence of knee pain was 25% (95% CI 20 to 30) and the 12-month prevalence was 29% (95% CI 23 to 35), which was significantly higher than at any other site in the lower limb. On average, being female was not associated with lower limb musculoskeletal pain either currently (OR 1.3, 95% CI 0.9 to 1.9) or over the previous 12 months (OR 1.2, 95% CI 0.9 to 1.8), whereas being older than 50 years was, both for current pain (OR 4.1, 95% CI 2.8 to 6.1) and pain over the previous 12 months (OR 4.0, 95% CI 2.7 to 6.0). Observation walks through the villages revealed people squatting for sustained periods, carrying heavy loads for long distances, wearing poor quality footwear, and with severe bowing of the legs but no obesity.

CONCLUSION

Lower limb musculoskeletal pain, particularly knee pain, is common in this rural Tibetan population. They live an extremely arduous life that appears to place considerable pressure on their knees.

Knee extensor strength does not protect against incident knee symptoms at 30 months in the multicenter knee osteoarthritis (MOST) cohort

OBJECTIVE

Knee extensor weakness has not been associated consistently with the risk for incident knee pain. Additionally, the balance of hamstring-to-quadriceps strength (H:Q ratio) may affect risk and has not been studied. The authors determined whether knee extensor weakness or muscle imbalance is a risk factor for development of frequent knee pain or stiffness and whether the effect is modified by lower limb alignment.

DESIGN

Observational study.

SETTING

Community.

PARTICIPANTS

Community-dwelling adults ages 50-79 years with or at risk of knee osteoarthritis based on obesity, knee injury, or surgery. A total of 1269 knees from women and 1006 knees from men without frequent knee symptoms at baseline and with 15- or 30- month follow-up outcome data were included.

ASSESSMENT OF RISK FACTORS

Isokinetic knee extensor and flexor strength as well as radiographic hip-knee-ankle alignment were measured at baseline. H:Q ratio was dichotomized, with normal being considered to be >/=0.6.

MAIN OUTCOME MEASUREMENTS

Frequent knee symptoms at 15- or 30-month follow-up (frequent knee pain, aching, or stiffness on most days of the past month reported at both telephone contact just before and at visit).

RESULTS

Mean +/- SD age was 62.2 +/- 8.0 years and mean body mass index (BMI) was 30.1 +/- 5.4 kg/m(2). Mean peak knee extensor strength (KES) was 132.6 +/- 42.4 and 76.9 +/- 25.3 N.m in men and women, respectively. Approximately 50% of knees in men and 59% of knees in women had an H:Q ratio <0.6. A total of 307 of 2275 eligible knees developed frequent knee symptoms at follow-up. Logistic regression controlling for age, BMI, femoral neck bone mineral density, activity score, and baseline Kellgren Lawrence grade revealed that neither KES nor H:Q ratio predicted the development of knee symptoms in gender-stratified or combined analyses. These results were unaffected by adjusting for lower limb alignment.

CONCLUSIONS

Neither concentric quadriceps strength nor H:Q ratios predicted the development of frequent knee symptoms at 15- or 30-month follow-up in this cohort.

Sex, gender, and pain: a review of recent clinical and experimental findings

Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed.

PERSPECTIVE

This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men.

Gender differences influence the outcome of geriatric rehabilitation following hip fracture

Hip fracture represents the most dramatic expression of the disease, in terms of morbidity, medical cost and mortality. The incidence of hip fracture increases substantially with age. The purpose of this study was to evaluate the association between gender and geriatric rehabilitation outcome after traumatic hip fracture. Ninety-nine community-dwelling elderly patients (older than 65 years), 64 women and 35 men, who were admitted to geriatric rehabilitation after operated hip fracture were studied. We assessed the patients' clinical and demographic data, preoperative risk (ASA), type of fracture and orthopedic repair, pain intensity (VAS), cognitive (MMSE), mood (Zung IDS), and functional status (FIM) on admission and at the end of geriatric rehabilitation. Men had higher mean number of comorbid conditions at the time of the fracture. Men recovered more from depressed mood in comparison with women during the rehabilitation. Significant improvement in FIM motor subscore on discharge was found in both groups. The FIM motor subscore gain was higher in men (24.47) in comparison with women (19.22, p=0.036). Those differences were demonstrated in mean subscores of transfers (p=0.004), and locomotion (p=0.019). Women were more functionally dependent in locomotion, transfers and sphincter control. There were no differences between the groups by duration on rehabilitation stay. Recovery after hip fracture depends in large part on the pre-fracture health and functional ability of the patient. Gender differences in functional recovery may affect therapeutic and rehabilitative decision making. Functional recovery after traumatic hip fracture was better in men in comparison with women.

Epidemiology of hip and knee pain in a community based sample of Italian persons aged 65 and older

OBJECTIVE

To describe prevalence, characteristics and correlates of hip pain (HP) and knee pain (KP) in an Italian community based cohort aged 65 and older (65+).

METHOD

Baseline survey (1998-2000), population-based study in the Chianti area (Tuscany, Italy); 1299 persons aged 65+ were selected from the city registry of Greve in Chianti and Bagno a Ripoli (multistage sampling method); 1006 participants (564 women and 442 men, age 75.2+/-7.1) provided information for this analysis. Persons reporting HP/KP in the past 4 weeks were recorded and their Western Ontario and McMaster University Osteoarthritis Index pain score (WPS-range 0-20) calculated. Potential correlates of HP/KP, including clinical, lifestyle and psycho-social features and physical measures, were tested in age- and gender-adjusted regression analyses and then entered a multivariate regression model.

RESULTS

HP was reported by 11.9% participants, while 22.4% reported KP and 7.2% both conditions. Climbing/descending stairs and walking were the activities eliciting more severe pain in either condition. Average WPSs were 5.6+/-3.5 for HP and 5.4+/-10.4 for KP. Both HP and KP were related to back pain, reduced hip abduction, reduced muscle power and increased trunk flexibility. HP was also related to KP and poor self-rated health (SRH), while KP to HP, foot pain, high body mass index, reduced knee passive flexion and knee extension torque, low education.

CONCLUSION

In a community sample of an Italian persons aged 65+, the prevalence of KP almost doubled that of HP. While both conditions were related to pain in other joints and specific joint impairment, only HP was related to poor SRH, and only KP to mechanical overload.

Prevalence of symptoms of knee or hip joints in older adults from the general population

BACKGROUND AND AIMS

The prevalence of knee and hip symptoms varies from study to study, or is unknown. The goals of this study were to determine the prevalence of these symptoms, of diagnosed osteoarthritis and the use of prostheses, by age and gender, in a sample of the general older population.

METHODS

We mailed a questionnaire to 11,002 people aged 60 to 90 years who were selected by stratified random sampling. The questionnaire included questions on pain, functional limitations, diagnosed osteoarthritis, previous operations on either or both joints, and sociodemographic data. Descriptive statistics were performed.

RESULTS

From 10,150 people who fulfilled the selection criteria, 74.6% answered the questionnaire. Up to 49.2% of the subjects reported pain in either knee or hip or both, with pain in the knee reported more frequently (38.3%) than the hip (23.8%). Functional limitations were present in 51.6% of respondents, with 42.5% having limitations in the knees and 27.7% in the hips. The symptoms increased with age and were more prevalent in women. About 6.6% of respondents reported that they had already had prosthesis implant (hip 3.9%; knee 2.6%). The presence of a hip prosthesis was slightly lower in women than in men and more women had a knee prosthesis. Physicians had already diagnosed osteoarthritis in 38.5% of the sample, 19.4% of the hip and 31% of the knee.

CONCLUSIONS

The prevalence of pain symptoms is relatively high among older people, more often in the knee and, in both joints, more often in women, but the rate of prosthetic surgeries was low, which means that additional studies are necessary to gain insight into the healthcare needs of the population.

Gender difference in symptomatic radiographic knee osteoarthritis in the Knee Clinical Assessment--CAS(K): a prospective study in the general population

Background

A recent study of adults aged ≥50 years reporting knee pain found an excess of radiographic knee osteoarthritis (knee ROA) in symptomatic males compared to females. This was independent of age, BMI and other clinical signs and symptoms. Since this finding contradicts many previous studies, our objective was to explore four possible explanations for this gender difference: X-ray views, selection, occupation and non-articular conditions.

Methods

A community-based prospective study. 819 adults aged ≥50 years reporting knee pain in the previous 12 months were recruited by postal questionnaires to a research clinic involving plain radiography (weight-bearing posteroanterior semiflexed, supine skyline and lateral views), clinical interview and physical examination. Any knee ROA, ROA severity, tibiofemoral joint osteoarthritis (TJOA) and patellofemoral joint osteoarthritis (PJOA) were defined using all three radiographic views. Occupational class was derived from current or last job title. Proportions of each gender with symptomatic knee ROA were expressed as percentages, stratified by age; differences between genders were expressed as percentage differences with 95% confidence intervals.

Results

745 symptomatic participants were eligible and had complete X-ray data. Males had a higher occurrence (77%) of any knee ROA than females (61%). In 50–64 year olds, the excess in men was mild knee OA (particularly PJOA); in ≥65 year olds, the excess was both mild and moderate/severe knee OA (particularly combined TJOA/PJOA). This male excess persisted when using the posteroanterior view only (64% vs. 52%). The lowest level of participation in the clinic was symptomatic females aged 65+. Within each occupational class there were more males with symptomatic knee ROA than females. In those aged 50–64 years, non-articular conditions were equally common in both genders although, in those aged 65+, they occurred more frequently in symptomatic females (41%) than males (31%).

Conclusion

The excess of knee ROA among symptomatic males in this study seems unlikely to be attributable to the use of comprehensive X-ray views. Although prior occupational exposures and the presence of non-articular conditions cannot be fully excluded, selective non-participation bias seems the most likely explanation. This has implications for future study design.

Diagnosis and management of a patient with knee pain using the movement system impairment classification system

STUDY DESIGN

Case report.

BACKGROUND

Selecting the most effective conservative treatment for knee pain continues to be a challenge. An understanding of the underlying movement system impairment that is thought to contribute to the knee pain may assist in determining the most effective treatment. Our case report describes the treatment and outcomes of a patient with the proposed movement system impairment (MSI) diagnosis of tibiofemoral rotation.

CASE DESCRIPTION

The patient was a 50-year-old female with a 3-month history of left anteromedial knee pain. Her knee pain was aggravated with sitting, standing, and descending stairs. A standardized clinical examination was performed and the MSI diagnosis of tibiofemoral rotation was determined. The patient consistently reported an increase in pain with activities that produced abnormal motions or alignments of the lower extremity in the frontal and transverse planes. The patient was educated to modify symptom-provoking functional activities by restricting the abnormal motions and alignments of the lower extremity. Exercises were prescribed to address impairments of muscle length, muscle strength, and motor control proposed to contribute to the tibiofemoral rotation. Tape also was applied to the knee in an attempt to restrict tibiofemoral rotation.

OUTCOMES

The patient reported a cessation of pain and an improvement in her functional activities that occurred with correction of her knee alignment and movement pattern. Pain intensity was 2/10 at 1 week. At 10 weeks, pain intensity was 0/10 and the patient reported no limitations in sitting, standing, or descending stairs. The patient's score on the activities of daily living scale increased from 73% at the initial visit to 86% at 10 weeks and 96% at 1 year after therapy was discontinued.

DISCUSSION

This case report presented a patient with knee pain and an MSI diagnosis of tibiofemoral rotation. Diagnosis-specific treatment resulted in a cessation of the patient's pain and an improved ability to perform functional activities.

The role of pain in the recovery of instrumental and social functioning after hip fracture

OBJECTIVE

It is critical to identify modifiable factors associated with functional recovery from hip fracture. The authors examined the association between pain intensity and two functional endpoints-instrumental activities of daily living and social activity participation-after hip fracture.

METHOD

A total of 270 cognitively intact, community-dwelling persons older than 65 who underwent surgical hip fracture repair in New Haven, Connecticut, were followed for 12 months.

RESULTS

Pain intensity was strongly negatively associated with both instrumental and social functioning (p values < .001). Increases in pain intensity between 6 and 12 months were also associated with concurrent decreases in function (p values < .001). These relationships were partly explained by depressive symptoms and a marker of physical ability-gait speed.

DISCUSSION

Interventions to control pain may enhance functional status after hip fracture; however, pain relief must be maintained to sustain recovery. Attention to the complex relationships among pain, depressive symptoms, and physical impairments should inform intervention development.

Pain, lower-extremity muscle strength, and physical function among older Mexican Americans

OBJECTIVE

To examine the relation between pain on weight bearing, lower-extremity muscle strength, and physical function among older Mexican Americans.

DESIGN

Cross-sectional study.

SETTING

Five Southwestern states: Texas, New Mexico, Colorado, Arizona, and California.

PARTICIPANTS

A population-based sample of 544 noninstitutionalized Mexican-American men and women age 71 years and older.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain on weight bearing, lower-extremity muscle strength, and physical function.

RESULTS

Of the 544 subjects, 244 (44.9%) reported pain on weight bearing. Mean muscle strength in men ranged from 9.3 kg for knee extension, 12.8 kg for hip flexion, to 13.0 kg for hip abduction. In women, mean strength ranged from 6.6 kg for knee extension, 9.5 kg for hip flexion, to 8.6 kg for hip abduction. Mean of physical function score was 70.7 for men and 60.6 for women. Pain on weight bearing was negatively associated with summary lower-extremity muscle strength only in women (-.05, P < .001) after controlling for all covariates. Pain on weight bearing was negatively associated with physical function in both men (-15.33, P < .001) and women (-11.03, P < .001), and lower-extremity muscle strength was positively associated with physical function in both men (37.77, P < .001) and women (73.50, P < .001), after controlling for all covariates.

CONCLUSIONS

Among older Mexican Americans, the presence of pain was associated with decreased muscle strength in women and decreased physical function in both men and women. High muscle strength was associated with high physical function in both men and women.

Osteoarthritis and meniscus disorders of the knee as occupational diseases of miners

AIM

To determine whether kneeling or squatting for prolonged periods is sufficiently causally associated with an increased risk of injury or degenerative disease of the knee joint as to meet the classic criteria to be considered an occupational disease of coal miners for whom these are or have been routine working postures.

METHOD

Systematic literature searches were made for studies relating to kneeling and squatting as part of the working environment of coal mines and the role of these postures in causation of knee disorders in coal miners, analogous occupations, populations, and communities. The working environment and potentially damaging forces on the knee when kneeling or squatting were described. Papers on the incidence or prevalence of knee disorders in occupational and other groups were scored against five criteria independently by each author, and from this a single consensus score representing the overall strength of evidence given by the research was awarded. The evidence was then weighed against the criteria for an occupational disease.

RESULTS

Nineteen published papers were scored, the majority of which focussed on osteoarthritis as the outcome of interest. Few of the studies found focussed specifically on miners, and those that did tended to involve small numbers of subjects and were carried out before 1960, when the mining population was at its largest but epidemiological evidence of the risk factors for knee disorders was not well established. The non-mining studies in the review represent groups of workers with a similar or lesser kneeling content in their work.

CONCLUSION

The papers reviewed provide sufficient evidence to conclude that work involving kneeling and/or squatting is causally associated with an increased risk of osteoarthritis of the knee. In some of the more recent epidemiologically sound studies, frequent or prolonged kneeling or squatting doubles the general risk of osteoarthritis of the knees found in the general population. This may be of particular importance in welfare and medico-legal situations. There was also evidence to suggest that lifting, in combination with kneeling/squatting, an activity also performed by miners in the course of their work, is associated with an excess risk of osteoarthritis above that attributed to kneeling/squatting alone.