Occupational kneeling and radiographic tibiofemoral and patellofemoral osteoarthritis

Physiopathology of patello-femoral osteoarthritis: current concepts

Patellofemoral osteoarthritis (PFOA) is the result of degeneration and loss of articular cartilage of the patella and trochlea, and is a common cause of anterior knee pain. PFOA is triggered by insufficient adaptation to overload of the articular cartilage of the PF joint created by abnormal biomechanics. It is important to understand the pathophysiology and natural history to make the diagnosis and to plan treatment. Innate factors including malalignment, patellar instability, kinematic disorders, and acquired factors like trauma, obesity, and endocrine diseases have been found to be causes of PFOA. Genetic predisposition is also described as a contributing cause but without much scientific evidence. The diagnosis will be based on clinical manifestations, such as anterior knee pain aggravated by overloading activities, identification of risk factors, and exclusion of referred pain from other pathologies, followed by a systematic and structured physical examination. Imaging will be useful for assessing the presence of early osteoarthritis in the other compartments, for classification of the PFOA, and to identify features to establish an adequate treatment. This paper discusses varying management options for different causes of patellofemoral disease and explains the complexity of the PF joint and its often poorly understood biomechanics.

The ability to kneel before and after total knee arthroplasty : the role of the pattern of osteoarthritis and the position of the femoral component

AIMS

The aims of this study were to investigate the ability to kneel after total knee arthroplasty (TKA) without patellar resurfacing, and its effect on patient-reported outcome measures (PROMs). Secondary aims included identifying which kneeling positions were most important to patients, and the influence of radiological parameters on the ability to kneel before and after TKA.

METHODS

This prospective longitudinal study involved 209 patients who underwent single radius cruciate-retaining TKA without patellar resurfacing. Preoperative EuroQol five-dimension questionnaire (EQ-5D), Oxford Knee Score (OKS), and the ability to achieve four kneeling positions were assessed including a single leg kneel, a double leg kneel, a high-flexion kneel, and a praying position. The severity of radiological osteoarthritis (OA) was graded and the pattern of OA was recorded intraoperatively. The flexion of the femoral component, posterior condylar offset, and anterior femoral offset were measured radiologically. At two to four years postoperatively, 151 patients with a mean age of 70.0 years (SD 9.44) were included. Their mean BMI was 30.4 kg/m² (SD 5.36) and 60 were male (40%). They completed EQ-5D, OKS, and Kujala scores, assessments of the ability to kneel, and a visual analogue scale for anterior knee pain and satisfaction.

RESULTS

The ability to kneel in the four positions improved in between 29 (19%) and 53 patients (35%) after TKA, but declined in between 35 (23%) and 46 patients (30%). Single-leg kneeling was most important to patients. After TKA, 62 patients (41%) were unable to achieve a single-leg kneel, 76 (50%) were unable to achieve a double-leg kneel, 102 (68%) were unable to achieve a high-flexion kneel and 61 (40%) were unable to achieve a praying position. Posterolateral cartilage loss significantly affected preoperative deep flexion kneeling (p = 0.019). A postoperative inability to kneel was significantly associated with worse OKS, Kujala scores, and satisfaction (p < 0.05). Multivariable regression analysis identified significant independent associations with the ability to kneel after TKA (p < 0.05): better preoperative EQ-5D and flexion of the femoral component for single-leg kneeling; the ability to achieve it preoperatively and flexion of the femoral component for double-leg kneeling; male sex for high-flexion kneeling; and the ability to achieve it preoperatively, anterior femoral offset, and patellar cartilage loss for the praying position.

CONCLUSION

The ability to kneel was important to patients and significantly influenced knee-specific PROMs, but was poorly restored by TKA with equal chances of improvement or decline. Cite this article: Bone Joint J 2021;103-B(9):1514-1525.

Lower Limb Movement Pattern Differences Between Males and Females in Squatting and Kneeling

Movement pattern differences may contribute to differential injury or disease prevalence between individuals. The purpose of this study was to identify lower limb movement patterns in high knee flexion, a risk factor for knee osteoarthritis, and to investigate kinematic differences between males and females, as females typically develop knee osteoarthritis more commonly and severely than males. Lower extremity kinematic data were recorded from 110 participants completing 4 variations of squatting and kneeling. Principal component analysis was used to identify principal movements associated with the largest variability in the sample. Across the tasks, similar principal movements emerged at maximal flexion and during transitions. At maximal flexion, females achieved greater knee flexion, facilitated by a wider base of support, which may alter posterior and lateral tibiofemoral stress. Principal movements also detected differences in movement temporality between males and females. When these temporal differences occur due to alterations in movement velocity and/or acceleration, they may elicit changes in muscle activation and knee joint stress. Movement variability identified in the current study provides a framework for potential modifiable factors in high knee flexion, such as foot position, and suggests that kinematic differences between the sexes may contribute to differences in knee osteoarthritis progression.

Occupational Risk in Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Observational Studies

OBJECTIVE

To assess the association between occupational exposures and knee osteoarthritis (OA).

METHODS

We systematically searched for observational studies that examined the relationship between occupational exposures and knee OA and total knee replacement. Four databases were searched up to October 1, 2019. Two reviewers independently assessed study quality using the Newcastle-Ottawa Scale and evidence quality using the Grading of Recommendations Assessment, Development and Evaluation approach. Subgroup meta-analyses were conducted for important study characteristics and each type of occupational exposure. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated for the meta-analysis using random-effects models.

RESULTS

Eighty eligible studies were identified including 25 case-control (n = 20,505 total participants), 36 cross-sectional (n = 139,463 total participants), and 19 cohort studies (n = 16,824,492 total participants). A synthesis of 71 studies suggested increased odds of knee OA (OR 1.52 [95% CI 1.37-1.69]) by combining different physically demanding jobs and occupational activities as compared to sedentary occupations and/or low-exposure groups. Odds of knee OA were greater in males and in industry-based studies and studies assessing lifetime occupational exposures. There were 9 specific job titles that were associated with knee OA, including farmer, builder, metal worker, and floor layer. Occupational lifting, kneeling, climbing, squatting, and standing were all associated with higher odds of knee OA as compared to the odds of knee OA in sedentary workers.

CONCLUSION

Strenuous, physically demanding occupations and occupational activities were associated with increased odds of knee OA as supported by moderate-quality evidence. Specifically, agricultural and construction sectors, which typically involve heavy lifting, frequent climbing, prolonged kneeling, squatting, and standing, carried increased odds of knee OA.

Kneeling as a risk factor of patellofemoral joint cartilage damage worsening: an exploratory analysis on the Osteoarthritis Initiative

OBJECTIVES

To determine whether kneeling activity is associated with the MRI measures of patellofemoral (PF) joint cartilage damage worsening in subjects with/without patella alta (PA).

METHODS

Baseline and 24-month 3-T MR images and semi-quantitative MRI Osteoarthritis Knee Score (MOAKS) of PF joint of 600 subjects from the FNIH study, a nested study within the Osteoarthritis Initiative (OAI), were extracted. At baseline visit, subjects were asked how many days per week they participated in kneeling activities lasted ≥ 30 min. Insall-Salvati ratio (ISR) (patellar tendon/patellar height) was measured on baseline MRIs by a musculoskeletal radiologist; ISR ≥ 1.3 was considered PA. Regression analysis adjusted for confounding variables was used to assess the impact of kneeling on worsening of MOAKS cartilage over 24 months. The potential moderating effect of PA was evaluated using adjusted regression analysis.

RESULTS

Six hundred subjects (58.8% female, years, BMI = 30.7 ± 4.8 kg/m²) were included; 13.7%, 6.2%, and 5.5% of participants reported 1 day, 2-5 days, and ≥ 6 days of kneeling activities per week. A higher frequency of kneeling activity was associated with the increased risk of MOAKS cartilage score worsening (adjusted OR (95% CI): 2.33 (1.08-5.06)). Stratification analysis showed that only ≥ 6 days/week of kneeling activities was associated with the worsening of MOAKS cartilage scores (2.74 (1.03-7.27)). When we included the presence of PA in regression models, the OR (95% CI) for the association between kneeling and PF cartilage damage will decrease to 1.26 (0.78-2.04), suggesting the potential role of PA as the moderator variable.

CONCLUSION

Extensive kneeling activity (≥ 6 days/week) may be associated with the MRI-based worsening of PF cartilage damage, specifically in subjects with an underlying patella alta.

KEY POINTS

• Frequent daily kneeling activity is associated with a higher risk of patellofemoral cartilage damage resulting in patellofemoral osteoarthritis. • The cartilage damage associated with extensive kneeling activity may be worse in subjects with an underlying patella alta (i.e., high-riding patella).

Risk factors for development of lower limb osteoarthritis in physically demanding occupations: A systematic review and meta-analysis

This systematic review and meta-analysis identified and critically reviewed the findings of recent studies (last 15 years) examining relationships between specific physically demanding occupations or occupational tasks and development of lower limb osteoarthritis (OA). Twenty-eight studies with 266,227 cases of lower limb OA were included. Occupational tasks contributing to OA included farming, floor laying, and brick laying. Activities significantly contributing to the risk of knee OA were lifting heavy loads (>10 kg/week) (odds ratio [OR] = 1.52, 95% confidence interval [95%CI] 1.29-1.79), squatting/kneeling (OR = 1.69, 95%CI 1.15-2.49), standing (>2 h/daily) (OR = 1.22 95%CI 1.02-1.46) and walking (OR = 1.40 95%CI 1.14-1.73). Lifting contributed significantly to the risk of hip OA (OR = 1.35, 95%CI 1.16-1.57). The effects of occupational exposures appear to be magnified by previous injury and BMI >25 kg/m². Since specific occupational activities increase OA risk, ergonomist should encourage the use of existing tools, or oversee the design of new tools that may decrease exposure to such activities.

Ex vivo physiological compression of human osteoarthritis cartilage modulates cellular and matrix components

Mechanical stimulation appears to play a key role in cartilage homeostasis maintenance, but it can also contribute to osteoarthritis (OA) pathogenesis. Accumulating evidence suggests that cartilage loading in the physiological range contributes to tissue integrity maintenance, whereas excessive or reduced loading have catabolic effects. However, how mechanical stimuli can regulate joint homeostasis is still not completely elucidated and few data are available on human cartilage. We aimed at investigating human OA cartilage response to ex vivo loading at physiological intensity. Cartilage explants from ten OA patients were subjected to ex vivo controlled compression, then recovered and used for gene and protein expression analysis of cartilage homeostasis markers. Compressed samples were compared to uncompressed ones in presence or without interleukin 1β (IL-1β) or interleukin 4 (IL-4). Cartilage explants compressed in combination with IL-4 treatment showed the best histological scores. Mechanical stimulation was able to significantly modify the expression of collagen type II (collagen 2), aggrecan, SOX9 transcription factor, cartilage oligomeric matrix protein (COMP), collagen degradation marker C2C and vascular endothelial growth factor (VEGF). Conversely, ADAMTS4 metallopeptidase, interleukin 4 receptor alpha (IL4Rα), chondroitin sulfate 846 epitope (CS846), procollagen type 2 C-propeptide (CPII) and glycosaminoglycans (GAG) appeared not modulated. Our data suggest that physiological compression of OA human cartilage modulates the inflammatory milieu by differently affecting the expression of components and homeostasis regulators of the cartilage extracellular matrix.

Bone Defects in Revision Total Knee Arthroplasty and Management

This article reviews the recent updates in revision of total knee arthroplasty (RTKA). We reviewed the recent articles on RTKA in databases including PubMed, Google Scholar, and SCOPUS. Total knee arthroplasty (TKA) involves the replacement of all three compartments of the knee in surgery of the knee joint to restore capacity and function. TKA is one of the most common and reliable surgical treatment options for the treatment of knee diseases. However, some patients require revision of TKA (RTKA) after primary TKA for various reasons, including mechanical wear, implant loosening or breakage, malalignment, infection, instability, periprosthetic fracture, and persistent stiffness. Unfortunately, the overall outcome of RTKA is not as satisfactory as for primary TKA due to the uncertainty regarding the actual success rate and the risk factors for failure. Cementation, modular metal augmentation, bone grafting, autologous bone grafting, allogenic bone grafting, impactation bone grafting, structural bone allografting, metaphyseal fixation, using porous titanium coated press fit metaphyseal sleeves and porous tantalum structural cones, and megaprostheses or customized prostheses are the currently available management options for RTKA. However, most of the management systems possess specific complications. Novel approaches should be developed to improve functional capacity, implant survival rates, and quality of life in a cost‐efficient manner.

Knee pain in nursing home workers after implementation of a safe resident handling program

PURPOSE

Approximately 25-30% of nursing personnel experience knee pain (KP). We sought to identify physical and psychosocial work exposures, and personal factors related to prevalent, incident, and persistent KP 5-8 years after safe resident handing program (SRHP) implementation in nursing homes.

METHODS

Health and exposure information was obtained from worker surveys 5-6 years ("F5") and 7-8 years ("F6") post-SRHP implementation. Prevalent KP correlates were examined at F5; persistent and incident KP predictors were analyzed at F6, utilizing robust Poisson multivariable regression.

RESULTS

F5 KP prevalence (19.7%) was associated with combined physical exposures, and with either high job strain or low social support, in separate models. Two-year persistent KP was similarly associated with these psychosocial exposures. Being overweight was associated with KP in all analyses.

CONCLUSIONS

The SRHP program did not eliminate knee physical loading, which should be reduced to prevent nursing home worker KP. Workplace psychosocial exposures (high job strain, low social support) also appeared germane.

Superolateral Hoffa's fat pad (SHFP) oedema and patellar cartilage volume loss: quantitative analysis using longitudinal data from the Foundation for the National Institute of Health (FNIH) Osteoarthritis Biomarkers Consortium

OBJECTIVES

To determine the association of superolateral Hoffa's fat pad (SHFP) oedema and patellofemoral joint structural damage in participants of Foundation for the National Institute of Health Osteoarthritis Biomarkers Consortium study.

METHODS

Baseline and 24-month MRIs of 600 subjects were assessed. The presence of SHFP oedema (using 0-3 grading scale) and patellar morphology metrics were determined using baseline MRI. Quantitative patellar cartilage volume and semi-quantitative MRI osteoarthritis knee score (MOAKS) variables were extracted. The associations between SHFP oedema and patellar cartilage damage, bone marrow lesion (BML), osteophyte and morphology were evaluated in cross-sectional model. In longitudinal analysis, the associations between oedema and cartilage volume loss (defined using reliable change index) and MOAKS worsening were evaluated.

RESULTS

In cross-sectional evaluations, the presence of SHFP oedema was associated with simultaneous lateral patellar cartilage/BML defects and inferior-medial patellar osteophyte size. A significant positive correlation between the degree of patella alta and SHFP oedema was detected (r = 0.259, p < 0.001). The presence of oedema was associated with 24-month cartilage volume loss (odds ratio (OR) 2.11, 95% confidence interval 1.46-3.06) and medial patellar BML size (OR 1.92 (1.15-3.21)) and number (OR 2.50 (1.29-4.88)) worsening. The optimal cut-off value for the grade of baseline SHFP oedema regarding both presence and worsening of patellar structural damage was ≥ 1 (presence of any SHFP hyperintensity).

CONCLUSIONS

The presence of SHFP oedema could be considered as a predictor of future patellar cartilage loss and BML worsening, and an indicator of simultaneous cartilage, BML and osteophyte defects.

KEY POINTS

• SHFP oedema was associated with simultaneous lateral patellar OA-related structural damage. • SHFP oedema was associated with longitudinal patellar cartilage loss over 24 months. • SHFP oedema could be considered as indicator and predictor of patellar OA.

The prevalence of radiographic and MRI-defined patellofemoral osteoarthritis and structural pathology: a systematic review and meta-analysis

BACKGROUND

Patellofemoral osteoarthritis (PF OA) is more prevalent than previously thought and contributes to patient's suffering from knee OA. Synthesis of prevalence data can provide estimates of the burden of PF OA.

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis on the prevalence of PF OA and structural damage based on radiography and MRI studies in different populations.

METHODS

We searched six electronic databases and reference lists of relevant cross-sectional and observational studies reporting the prevalence of PF OA. Two independent reviewers appraised methodological quality. Where possible, data were pooled using the following categories: radiography and MRI studies.

RESULTS

Eighty-five studies that reported the prevalence of patellofemoral OA and structural damage were included in this systematic review. Meta-analysis revealed a high prevalence of radiographic PF OA in knee pain or symptomatic knee OA (43%), radiographic knee OA or at risk of developing OA (48%) and radiographic and symptomatic knee OA (57%) cohorts. The MRI-defined structural PF damage in knee pain or symptomatic population was 32% and 52% based on bone marrow lesion and cartilage defect, respectively.

CONCLUSION

One half of people with knee pain or radiographic OA have patellofemoral involvement. Prevalence of MRI findings was high in symptomatic and asymptomatic population. These pooled data and the variability found can provide evidence for future research addressing risk factors and treatments for PF OA.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42016035649).

Patellar position in weight-bearing radiographs compared with non-weight-bearing: significance for the detection of osteoarthritis

Background Diagnosis and treatment of patellofemoral disorders including osteoarthritis are currently often based on imaging and clinical assessment with patients in the supine position. Purpose To evaluate differences in patellar position in the trochlear groove and to assess the detection of medial and lateral patellofemoral (PF) osteoarthritis (OA) on axial radiographs in supine and standing positions, respectively. Material and Methods Thirty-five women and 23 men (mean age, 56 years; age range, 18-87 years) referred for routine radiographic examinations of the knees were included. Axial radiographs of the PF joint in both supine non-weight-bearing and standing weight-bearing position in 30° knee flexion were obtained of 111 knees. Measurements performed on the radiographs: patellar tilt, patellar displacement, joint space width, and grade of OA according to Ahlbäck. Results From supine to standing position the patella moved medially and medial joint space width and lateral patellar tilt angle decreased ( P < 0.0001 for the three measured parameters). In the standing position, medial PF OA was observed in 19 knees compared to three knees in the supine position. Fourteen knees had lateral PF OA with almost unchanged grade of OA irrespective of position. Conclusion In weight-bearing positions, the patella is positioned medially in the trochlear groove compared to supine non-weight-bearing positions. Therefore, this study suggests that the common occurrence of medial PF OA can generally not be detected on axial radiographs in supine non-weight-bearing positions and confirms the importance of imaging the PF joint in standing weight-bearing positions.

Patient reported outcomes in patients undergoing arthroscopic partial meniscectomy for traumatic or degenerative meniscal tears: comparative prospective cohort study

OBJECTIVES

 To compare patient reported outcomes from before surgery to 52 weeks after surgery between individuals undergoing arthroscopic partial meniscectomy for traumatic meniscal tears and those for degenerative meniscal tears.

DESIGN

 Comparative prospective cohort study.

SETTING

 Four public orthopaedic departments in the Region of Southern Denmark. Participants were recruited between 1 February 2013 and 31 January 2014, and at one of the original four hospitals from 1 February 2014 to 31 January 2015.

PARTICIPANTS

 Individuals selected from Knee Arthroscopy Cohort Southern Denmark, aged 18-55, and undergoing arthroscopic partial meniscectomy for a traumatic or degenerative meniscal tear (defined by a combination of age and symptom onset).

INTERVENTIONS

 Both participant groups underwent arthroscopic partial meniscectomy for a meniscal tear, with operating surgeons recording relevant information on knee pathology. Patient reported outcomes were recorded via online questionnaires.

MAIN OUTCOME MEASURES

 Primary outcome was the average between-group difference in change on four of five subscales of the knee injury and osteoarthritis outcome score (KOOS). The four subscales covered pain, symptoms, sport and recreational function, and quality of life (KOOS₄). A 95% confidence interval excluding differences greater than 10 KOOS points between groups was interpreted as absence of a clinically meaningful difference. Analyses adjusted for age, sex, and body mass index.

RESULTS

 397 eligible adults (42% women) with a traumatic or degenerative meniscal tear (n=141, mean age 38.7 years (standard deviation 10.9); n=256, 46.6 years (6.4); respectively) were included in the main analysis. At 52 weeks after arthroscopic partial meniscectomy, 55 (14%) patients were lost to follow-up. Statistically, participants with degenerative meniscal tears had a significantly larger improvement in KOOS₄ scores than those with traumatic tears (adjusted between-group difference -5.1 (95% confidence interval -8.9 to -1.3); P=0.008). In the analysis including KOOS₄ score at all time points, a significant time-by-group interaction was observed in both the unadjusted (P=0.025) and adjusted analysis (P=0.024), indicating better self-reported outcomes in participants with degenerative tears. However, the difference between groups was at no time point considered clinically meaningful.

CONCLUSIONS

 These results question the current tenet that patients with traumatic meniscal tears experience greater improvements in patient reported outcomes after arthroscopic partial meniscectomy than patients with degenerative tears.Trial registration ClinicalTrials.gov identifier NCT01871272.

Evaluation of knee joint forces during kneeling work with different kneepads

The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work.

A Cohort Study on Meniscal Lesions among Airport Baggage Handlers

Meniscal lesions are common and may contribute to the development of knee arthrosis. A few case-control and cross-sectional studies have identified knee-straining work as risk factors for meniscal lesions, but exposure-response relations and the role of specific exposures are uncertain, and previous results may be sensitive to reporting and selection bias. We examined the relation between meniscal lesions and cumulative exposure to heavy lifting in a prospective register-based study with complete follow-up and independent information on exposure and outcome. We established a cohort of unskilled men employed at Copenhagen Airport or in other companies in the metropolitan Copenhagen area from 1990 to 2012 (the Copenhagen Airport Cohort). The cohort at risk included 3,307 airport baggage handlers with heavy lifting and kneeling or squatting work tasks and 63,934 referents with a similar socioeconomic background and less knee-straining work. Baggage handlers lifted suitcases with an average weight of approximately 15 kg, in total approximately five tonnes during a 9-hour workday. The cohort was followed in the National Patient Register and Civil Registration System. The outcome was a first time hospital diagnosis or surgery of a meniscal lesion. Baggage handlers had a higher incidence of meniscal lesions than the referents. Within baggage handlers spline regression showed that the incidence rate ratio was 1.91 (95% confidence interval: 1.29-2.84) after five years as a baggage handler and then decreased slowly to reach unity after approximately 30 years, adjusted for effects of potential confounders. This relation between baggage handling and meniscal lesions was present for work on the apron which involves lifting in a kneeling or squatting position, but not in the baggage hall, which only involves lifting in standing positions. The results support that long-term heavy lifting in a kneeling or squatting position is a risk factor for the development of symptomatic meniscal lesions.

Comparison of musculoskeletal disorder health claims between construction floor layers and a general working population

OBJECTIVES

Compare rates of medical insurance claims for musculoskeletal disorders (MSD) between workers in a construction trade and a general worker population to determine if higher physical exposures in construction lead to higher rates of claims on personal medical insurance.

METHODS

Health insurance claims between 2006 and 2010 from floor layers were frequency matched by age, gender, eligibility time and geographic location to claims from insured workers in general industry obtained from MarketScan. We extracted MSD claims and dates of service from six regions of the body: neck, low back, knee, lower extremity, shoulder and distal arm, and evaluated differences in claim rates.

RESULTS

Fifty-one per cent of floor layers (n=1475) experienced musculoskeletal claims compared with 39% of MarketScan members (p<0.001). Claim rates were higher for floor layers across all body regions with nearly double the rate ratios for the knee and neck regions (RR 2.10 and 2.07). The excess risk was greatest for the neck and low back regions; younger workers had disproportionately higher rates in the knee, neck, low back and distal arm. A larger proportion of floor layers (22%) filed MSD claims in more than one body region compared with general workers (10%; p<0.001).

CONCLUSIONS

Floor layers have markedly higher rates of MSD claims compared with a general worker population, suggesting a shifting of medical costs for work-related MSD to personal health insurance. The occurrence of disorders in multiple body regions and among the youngest workers highlights the need for improved work methods and tools for construction workers.

Exploring physical exposures and identifying high-risk work tasks within the floor layer trade

INTRODUCTION

Floor layers have high rates of musculoskeletal disorders yet few studies have examined their work exposures. This study used observational methods to describe physical exposures within floor laying tasks.

METHODS

We analyzed 45 videos from 32 floor layers using Multimedia-Video Task Analysis software to determine the time in task, forces, postures, and repetitive hand movements for installation of four common flooring materials. We used the WISHA checklists to define exposure thresholds.

RESULTS

Most workers (91%) met the caution threshold for one or more exposures. Workers showed high exposures in multiple body parts with variability in exposures across tasks and for different materials. Prolonged exposures were seen for kneeling, poor neck and low back postures, and intermittent but frequent hand grip forces.

CONCLUSIONS

Floor layers experience prolonged awkward postures and high force physical exposures in multiple body parts, which probably contribute to their high rates of musculoskeletal disorders.

Occupational physical loading tasks and knee osteoarthritis: a review of the evidence

Purpose : To perform a systematic review with best evidence synthesis examining the literature on the relationship between occupational loading tasks and knee osteoarthritis (OA).

METHODS

Two databases were searched to identify articles published between 1946 and April, 2011. Eligible studies were those that (1) included adults reporting on their employment history; (2) measured individuals' exposure to work-related activities with heavy loading in the knee joint; and (3) identified presence of knee OA (determined by X-ray), cartilage defects associated with knee OA (identified by magnetic resonance imaging), or joint replacement surgery.

RESULTS

A total of 32 articles from 31 studies met the inclusion criteria. We found moderate evidence that combined heavy lifting and kneeling is a risk factor for knee OA, with odds ratios (OR) varying from 1.8 to 7.9, and limited evidence for heavy lifting (OR=1.4-7.3), kneeling (OR=1.5-6.9), stair climbing (OR=1.6-5.1), and occupational groups (OR=1.4-4.7) as risk factors. When examined by sex, moderate level evidence of knee OA was found in men; however, the evidence in women was limited.

CONCLUSIONS

Further high-quality prospective studies are warranted to provide further evidence on the role of occupational loading tasks in knee OA, particularly in women.

Level and determinants of knowledge of symptomatic knee osteoarthritis among railway workers in Malaysia

BACKGROUND

Symptomatic knee osteoarthritis, an ancient malady greatly impairing modern population quality of life, has stimulated global attention to find effective modes of prevention and intervention.

PURPOSE

This study aimed to assess factors affecting knowledge of symptomatic knee osteoarthritis (knee OA) among Malaysian railway workers.

METHODS

A cross-sectional study was conducted among 513 railway workers involving eight major states within Peninsular Malaysia using population-based sampling. The assessment instrument was a face-validated, prepiloted, self-administered instrument with sociodemographics and knowledge items on knee OA.

RESULTS

Mean (± SD) age of the respondents was 41.4 (± 10.7), with the majority aged 50 years or older (34.9%). Of the total respondents, 53.6% had low levels of knowledge of knee OA disease. Multivariate analysis found that four demographic predictors, age ≥ 50 years, family history of knee OA, self-awareness, and clinical diagnosis of the disease entity, were significantly associated with knowledge scores.

CONCLUSION

The finding of a low level knee OA knowledge among Malaysian railway workers points to an urgent need for massive information to be disseminated among the workers at risk to foster primary prevention and self-care.

Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To identify risk factors for osteoarthritis (OA) of the knee, hip, and ankle, including joint injury, sport, physical activity, overweight/obesity, and occupational activity, in all age groups.

BACKGROUND

OA is a significant health problem worldwide, affecting up to 10% of men and 18% of women over 60 years of age. There has not been a comprehensive review examining modifiable physical risk factors associated with the onset of OA. This evidence is important to inform the physiotherapy management of individuals following onset of OA.

METHODS

Twelve electronic databases were systematically reviewed. The studies selected met the following criteria: (1) original data; (2) joint injury, sport activity, physical activity, overweight/obesity, and/or occupational activity investigated as risk factors; (3) outcomes included OA (hip, knee, and/or ankle); and (4) analytic component of study design. The data extracted included study design, years of follow-up, study population, OA definition, risk factors, and results (effect estimates reported or calculated where available). The quality of evidence was assessed based on a modified version of the Downs and Black checklist.

RESULTS

Joint injury, obesity, and occupational activity were associated with an increased risk of OA of the knee and hip. Sport and physical activity produced inconsistent findings. Joint injury was identified as a significant risk factor for knee OA (combined odds ratio = 3.8; 95% confidence interval: 2.0, 7.2) and hip OA (combined odds ratio = 5.0; 95% confidence interval: 1.4, 18.2), as was previous meniscectomy with or without anterior cruciate ligament injury for knee OA (combined odds ratio = 7.4; 95% confidence interval: 4.0, 13.7). There is a paucity of research examining risk factors associated with ankle OA; this review identified only 2 studies with this outcome.

CONCLUSION

Joint injury, obesity, and occupational activity are associated with an increased risk of knee and hip OA. Some findings remain inconclusive, including levels of physical activity and sport specificity in individuals who do not suffer an injury. Early identification of individuals at risk for OA provides an opportunity for physiotherapy management or other interventions to modify risk-related behavior. There is a need in the literature for additional high-quality studies, such as prospective cohort studies, that minimize potential bias in examining the relationship between physical risk factors and OA.

LEVEL OF EVIDENCE

Prognosis, level 2a-.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis in the United States and is a leading cause of disability. It is typically defined in epidemiologic studies by radiographic findings and consideration of symptoms. Its incidence and prevalence are rising, likely related to the aging of the population and increasing obesity. Risk factors for OA include numerous person-level factors, such as age, sex, obesity, and genetics, as well as joint-specific factors that are likely reflective of abnormal loading of the joints. In studying OA, several methodologic challenges exist that can hamper our ability to identify pertinent relationships.

Symptomatic knee disorders in floor layers and graphic designers. A cross-sectional study

BACKGROUND

Previous studies have described an increased risk of developing tibio-femoral osteoarthritis (TF OA), meniscal tears and bursitis among those with a trade as floor layers. The purpose of this study was to analyse symptomatic knee disorders among floor layers that were highly exposed to kneeling work tasks compared to graphic designers without knee-demanding work tasks.

METHODS

Data on the Knee injury and Osteoarthritis Outcome Score (KOOS) were collected by questionnaires. In total 134 floor layers and 120 graphic designers had a bilateral radiographic knee examination to detect TF OA and patella-femoral (PF) OA. A random sample of 92 floor layers and 49 graphic designers had Magnetic Resonance Imaging (MRI) of both knees to examine meniscal tears. Means of the subscales of KOOS were compared by analysis of variance. The risk ratio of symptomatic knee disorders defined as a combination of radiological detected knee OA or MRI-detected meniscal tears combined with a low KOOS score was estimated by logistic regression in floor layers with 95% confidence interval (CI) and adjusted for age, body mass index, traumas, and knee-straining sports activities. Symptomatic knee OA or meniscal tears were defined as a combination of low KOOS-scores and radiographic or MRI pathology.

RESULTS

Symptomatic TF and medial meniscal tears were found in floor layers compared to graphic designers with odds ratios 2.6 (95%CI 0.99-6.9) and 2.04 (95% CI 0.77-5.5), respectively. There were no differences in PF OA. Floor layers scored significantly lower on all KOOS subscales compared to graphic designers. Significantly lower scores on the KOOS subscales were also found for radiographic TF and PF OA regardless of trade but not for meniscal tears.

CONCLUSIONS

The study showed an overall increased risk of developing symptomatic TF OA in a group of floor layers with a substantial amount of kneeling work positions. Prevention would be appropriate to reduce the proportion of kneeling postures e.g. by working with tools used from a standing working position.

MR Imaging of Intra- and Periarticular Cyst-Like Lesions of the Knee Joint in Workers with Occupational Kneeling

Objective. To determine the risk of intra- and periarticular cyst-like lesions of the knee joint in occupational kneeling. Methods. Magnetic resonance imaging of both knees (n = 282) was conducted in 92 male floor layers and 49 male graphic designers (referents), with a mean age of 55.6 years (range 42–70 years). The prevalence of cyst-like lesions was computed among floor layers and graphic designers, respectively, and associations with occupation summarized by odds ratio (OR) with 95% confidence intervals (CIs). Using logistic regression, models were adjusted for age, body mass index, knee injuries, and knee-straining sports. Results. Floor layers had a significantly higher prevalence of cyst-like lesions in the posterior part of the knee joint compared to graphic designers (OR 2.70, 95% CI 1.50–4.84). Floor layers also had a higher prevalence of fluid collections in the popliteus tendon recess (OR 2.17, 95% CI 0.99–4.77) and large cystic lesions of the popliteus muscle (OR 3.83, 95% CI 0.78–18.89). The prevalence of cystic lesions in the anterior part of the knee joint was low among floor layers (8.7%) and there was no significant difference between the two trade groups (P = 0.34). Conclusions. Occupational kneeling increases the risk of cyst-like lesions in the posterior part of the knee joint.

Occupational activities and osteoarthritis of the knee

BACKGROUND

The prevalence of knee osteoarthritis (OA) is rising and the search for interventions to mitigate risk is intensifying. This review considers the contribution of occupational activities to disease occurrence and the lessons for prevention.

SOURCES

Systematic search in Embase and Medline covering the period 1996 to November 2011.

AREAS OF AGREEMENT

Reasonably good evidence exists that physical work activities (especially kneeling, squatting, lifting and climbing) can cause and/or aggravate knee OA. These exposures should be reduced where possible. Obese workers with such exposures are at additional risk of knee OA and should therefore particularly be encouraged to lose weight. AREAS OF UNCERTAINTY/RESEARCH NEED: Workplace interventions and policies to prevent knee OA have seldom been evaluated. Moreover, their implementation can be problematic. However, the need for research to optimize the design of work in relation to knee OA is pressing, given population trends towards extended working life.

Response of cartilage and meniscus tissue explants to in vitro compressive overload

OBJECTIVE

To examine the relative susceptibility of cartilage and meniscus tissues to mechanical injury by applying a single, controlled overload and observing cellular, biochemical, and mechanical changes.

DESIGN

Cartilage and meniscus tissue explants in radial confinement were subjected to a range of injury by indenting to 40% strain at three different strain rates: 0.5%/s (slow), 5%/s (medium), or 50%/s (fast). Following injury, samples were cultured for either 1 or 9 days. Explants were assayed for cell metabolic activity, water content, and sulfated glycosaminoglycan (sGAG) content. Mechanical properties of explants were determined in torsional shear and unconfined compression. Conditioned medium was assayed for sGAG and lactate dehydrogenase (LDH) release.

RESULTS

Peak injury force increased with strain rate but both tissues displayed little to no macroscopic damage. Cell metabolism was lowest in medium and fast groups on day 1. Cell lysis increased with peak injury force and loading rate in both tissues. In contrast, sGAG content and release did not significantly vary with loading rate. Additionally, mechanical properties did not significantly vary with loading rate in either tissue.

CONCLUSION

By use of a custom confinement chamber, large peak forces were obtained without macroscopic destruction of the explants. At the loads achieved in this studied, cell damage was induced without detectable physical or compositional changes. These results indicate that sub-failure injury can induce biologic damage that may not be readily detected and could be an early event in osteoarthritis genesis.

Relationship between years in the trade and the development of radiographic knee osteoarthritis and MRI-detected meniscal tears and bursitis in floor layers. A cross-sectional study of a historical cohort

OBJECTIVES

An increased risk of developing knee disorders including radiographic knee osteoarthritis (OA) have been shown among workers with kneeling working demands. There may also be a dose-related association between duration of employment in occupations with kneeling work and development of radiographic knee OA and magnetic resonance imaging (MRI)-detected meniscal tears and bursitis.

DESIGN

A cross-sectional study of a historical cohort.

SETTING

Members of the trade unions for floor layers and graphic designers in Denmark.

PARTICIPANTS

92 male floor layers and 49 graphic designers aged 36-70 years were randomly selected among participants from a clinical and radiographic study of 156 floor layers and 152 graphic designers.

OUTCOME MEASURES

Radiographic tibiofemoral (TF) and patellofemoral (PF) knee-OA and MRI-detected meniscal tears and bursitis. Results were adjusted for age, earlier knee traumas, sports activities and body mass index in logistic regression models. Association between TF OA and years in the floor-laying trade was graphically examined by a restricted cubic spline with four knots.

RESULTS

Increase in number of years with exposure to kneeling work is associated with radiographic TF knee OA with ORs 0.7, 95% CI 0.07 to 4.42; OR 1.89, 95% CI 0.29 to 12.3; OR 4.82, 95% CI 1.38 to 17 for <20 years, 20-30 years and >30 years of kneeling work, respectively. MRI-verified medial meniscal tears was increased among subjects with kneeling work with OR 1.96, 95% CI 0.79 to 4.88 to OR 4.73, 95% CI 1.16 to 19.4 but was not associated with duration of employment. Periarticular bursitis was increased in subjects with <20 years of kneeling working activity. Lateral meniscal tears and PF knee OA were not associated with duration of kneeling working activity or with kneeling work in general.

CONCLUSIONS

The findings suggest a dose-response relationship for radiographic TF knee OA in floor layers with a significant amount of kneeling work and an increase of MRI-verified medial meniscal tears among workers with kneeling work.

Burden of work-related knee disorders in Washington State, 1999 to 2007

OBJECTIVE

To describe the burden of knee work-related musculoskeletal disorders (WMSDs).

METHODS

Knee WMSDs were identified using Washington State Fund workers' compensation data from 1999 to 2007 and analyzed by cost, industry, occupation, and claims incidence rates.

RESULTS

Knee WMSDs accounted for 7% of WMSD claims and 10% of WMSD costs. The rate of decline in claims incidence rates for knee WMSDs was similar to the rate of decline for all other WMSDs. Industries at highest risk for knee WMSDs included construction and building contractors. Occupations of concern included carpenters and truck drivers in men and nursing aides and housekeepers in women.

CONCLUSIONS

Between 1999 and 2007, Washington State Fund knee WMSDs were widespread and associated with a large cost. Identification of specific occupational knee WMSD risk factors in high-risk industries is needed to guide prevention efforts.

Occupational risk factors for osteoarthritis of the knee: a meta-analysis

INTRODUCTION

Systematic reviews agree that knee osteoarthritis (OA) is related to occupational activities, but have not quantified the overall risks.

METHODS

Systematic review of observational studies of knee OA and occupation. Job titles, elite sport, heavy work, kneeling, and other activities were included. Relative risk estimate and 95% confidence interval (CI) compared to sedentary work were retrieved or calculated for meta-analysis. Publication bias was examined with Egger tests and heterogeneity was determined with I(2) values and Q tests. Subgroup analysis was performed to examine causes of heterogeneity. A random effects model was performed to combine the data.

RESULTS

Studies of knee OA (n=51), persistent knee pain (n=12) and knee OA progression (n=3) were retrieved. Occupational risks for knee OA were examined in a total of 526,343 subjects in 8 cohort/prospective/longitudinal studies, 25 cross-sectional studies and 18 case control studies. The overall odds ratio (OR) was 1.61 (95% CI 1.45-1.78) with significant heterogeneity (I(2)=83.6%). Study designs showed a positive association between knee OA and occupational activities; cohort (OR 1.38, 95% CI 1.10-1.74), cross-sectional (OR 1.57, 95% CI 1.37-1.81) and case control (OR 1.80, 95% CI 1.48-2.19). Overall there was evidence of publication bias (P<0.0001) which was apparent in the cross-sectional and case control studies (P<0.0001 and P=0.0247 respectively).

CONCLUSIONS

Some occupational activities increase the risk of knee OA, although the influences of publication bias and heterogeneity are important limitations of this study. Prospective studies would greatly improve the evidence base.

Osteoarthritis prevention

PURPOSE OF REVIEW

We discuss recent published epidemiologic data regarding risk factors for incident and progressive knee osteoarthritis and related knee pain to identify targets for primary and secondary prevention. We also discuss recently identified methodologic challenges to the study of knee osteoarthritis, particularly osteoarthritis progression.

RECENT FINDINGS

Recent epidemiologic studies and systematic reviews of knee osteoarthritis have confirmed that being overweight and obese, and knee injuries increase the risk for incident knee osteoarthritis. Biomechanical risk factors such as leg-length inequalities and malalignment require further study. Obesity also appears to play a role in accelerating osteoarthritis worsening. However, with the exception of malalignment, no risk factors for knee osteoarthritis progression have been identified. Novel approaches to the study of knee pain have demonstrated a strong association between structural abnormalities and knee pain, contrary to the 'so-called' structure-symptom discordance, as well as between fluctuations of knee pain with changes in specific structural lesions. A number of methodologic issues, including conditioning on an intermediate stage of disease and depletion of susceptibles may explain, in part, the difficulty in identifying risk factors for knee osteoarthritis.

SUMMARY

There is strong epidemiologic evidence that being overweight or obese and knee injury are associated with increased risk of developing knee osteoarthritis. Further study is required to confirm associations of leg-length inequality and malalignment with incident knee osteoarthritis. Few new risk factors for progression of knee osteoarthritis have been identified in the past few years. Without such knowledge, secondary prevention of osteoarthritis remains challenging.

Risk factors for radiographic tibiofemoral knee osteoarthritis: the wuchuan osteoarthritis study

Objective. To investigate the risk factors of radiographic tibiafemoral knee osteoarthritis (OA). Methods. A population-based cross-sectional survey was conducted in Wuchuan County. A questionnaire and bilateral weight-bearing posterior-anterior semi-flexed knee radiographs were completed and read for Kellgren and Lawrence (K/L) grade and joint space narrowing (JSN; 0-3 scale) in each compartment. An logistic regression analysis was performed for radiographic tibiafemoral, lateral compartment, and medial compartment knee OA, respectively. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated. Results. Age, sex, and knee injury were strongly associated with tibiafemoral, lateral and medial compartment knee OA. BMI also had a dose-response relationship with them. Physical activity level, and physical activity exposure at work, not significantly though, were associated with an elevated risk for this three kinds of knee OA. Conclusions. Physical activity exposure increased the risk of knee OA. It was likely to be the heavier physical activity in Wuchuan osteoarthritis study that counteracted the BMI gap compared with the Beijing and the Framingham OA study. We verified that Chinese had a more valgus alignment of the knee compared with Caucasian population, and this provide a possible explanation why Chinese have a higher prevalence of lateral compartment OA.