There is a plethora of information available regarding knee pain assessments, clinical diagnoses, and treatment measures in patients. For this reason, a Task Force was commissioned to provide evidence-based guidelines to assist referring physicians, allied health personnel, and patients in making decisions concerning the management of knee pain. This task force comprised members of the American Medical Society for Sports Medicine, the American Academy of Family Physicians, the American Academy of Orthopaedic Surgeons, and the American Physical Therapy Association. It is the second set of comprehensive guidelines provided by this Task Force, the first set was published in 2000. These new guidelines are based on current best evidence and are presented as a series of recommended strategies with a focus on efficacy. It is hoped that these guidelines will be of most use to the subset of patients with knee pain who have substantial resultant functional limitations and/or participation restrictions. This document also provides a background to the field of knee pain and associated functional limitations as well as demonstrating the remaining clinical care gaps. By identifying and implementing the recommendations listed in this document, it is hoped that such gap areas can be addressed. This will provide the provision of best patient care and optimize patient outcomes. At the time of the Mosely et al. systematic review, it was considered that no previous clinical practice guidelines satisfied stringent identification and inclusion criteria. Therefore, the task force primarily aimed to provide such guidelines on the management of knee pain in patients that have functional deficits.
Workplace Factors Contributing to Knee Pain
The effect of knee OA was also seen in farmers owing to, again, the physically demanding nature of the job. High physical job demands often result in injuries, and to repair these injuries, workers tend to prolong their work to earn more money before seeking medical treatment. This is detrimental to the problem as studies show that twisting an already injured knee greatly increases the risk of OA. High physical job demands are indirectly linked to knee OA through injury, and injury is a major risk factor for the development of knee OA.
It has been found that improper ergonomics is associated with knee OA in the sense that knee OA is more likely to occur in jobs with higher levels of physical strain and a higher disability prevalence. A study on a diverse range of work suggested that those involving frequent heavy loads and level walking/stair climbing had higher odds of a total knee replacement due to OA. Another study examined lifetime occupational activity and the relative risk for total knee replacement due to OA, showing that the higher the physical demand and ability required at work, the greater the risk of OA and knee replacement. The effect of OA was also seen in a cohort of carpet layers suffering from knee pain and radiating knee symptoms, as it was found they had a higher risk of knee OA compared to referents matched by age, sex, and social class. This was all found to be due to the high physical demands of the job.
Improper ergonomics refer to an unsuitable working environment for the worker. This usually occurs when the physical aspects of the job do not match the physical capacity of the worker. There are two elements to consider in ergonomics, the first being the physical arrangement of the worker’s workplace in relation to others. This includes the height of the table, the placement of the phone, and the position of the keyboard and computer screen. These are vital considerations as awkward postures, such as reaching above shoulder height or twisting the wrist to one side, can lead to musculoskeletal problems. The second is the consideration of the tools and equipment of the job. Workers must use tools that are suitable for the task at hand and designed to exert minimum forces and postures on the body. An example of this would be workers using power tools to reduce the time and energy needed to complete a task. However, prolonged use of these tools can put unnecessary force on the body. This is also related to the concept of energy conservation, whereby the best way to do a task is the easiest way on the body. When this is achieved, there is a low risk of energy overload on the anatomical structures of the body.
Improper Ergonomics
Ergonomics, a term fairly familiar in workplace environments today, refers to the study of people’s efficiency in their working environment. More precisely, it focuses on how people can work more efficiently by altering their environment. With the advancement of technology over the last few decades, mobile devices have become an integral part of our lives. Gone are the days when pagers were widely used, having given way to smaller, sleeker mobile phones and PDAs. The newest technological advancement is the tablet, essentially a hybrid between a mobile phone and a laptop. These devices have become a necessity for work in various fields such as sales, administration, and healthcare. It is in healthcare where ergonomics should be given more attention. Devices such as ultrasound machines can weigh up to 40 pounds, which is a heavy load for a single machine, let alone for mobile ultrasound, which would require the machines to be lugged around various locations. It has often been pointed out that keyboards are too low for comfortable use, with an awkward chair and keyboard height potentially causing pressure on the leg joints. Steps have been taken to make improvements, such as a study conducted by the Laboratory of Rehabilitation Engineering, NPC (Neuromuscular Programme and Clinical Trials), with Tan Tock Seng’s Department of Physiotherapy. A new design for an ultrasound console was tested to improve its usability by reducing the size and weight, adding wheels, and adjusting the keyboard height to be ergonomic. Such approaches are potential directions for improving the working environment to be more knee joint-friendly.
Repetitive Movements
The repetitive motion can result in micro-traumatic injuries of the knee, and very often this type of injury is linked with a specific activity. Repetitive movements such as stair climbing, squatting, kneeling, and walking long distances increase the risk of development of knee osteoarthritis. In fact, work requiring kneeling and squatting are strong predictors of osteoarthritis and total knee replacement. The role of physical activity, including occupational and leisure time activities, in the development and progression of knee osteoarthritis is important when managing patients, as in some cases, the activity level must be modified to relieve symptoms. An understanding of the specific tasks that are causing knee symptoms can assist in targeting treatment and educating patients regarding their knee. This may involve simply modifying the tasks that aggravate the knee or, in more severe cases, a job or occupational change. High levels of static or peak force knee loading are thought to be a key mechanism of traumatic knee injury. The repetitive nature of high-load activities, such as heavy lifting and manual handling, increase the risk of a specific trauma, such as meniscal or articular cartilage damage. Static posture is often unrecognized as a high-force knee loading activity, and prolonged standing has been linked with the development of knee osteoarthritis. This is a common scenario in some occupations, such as teaching or nursing. Static posture in a knee-bent position carries a high risk of quadriceps fatigue, pain, and onset of patellofemoral joint osteoarthritis. Patellofemoral joint symptoms are common knee pain presentations and will be covered as a separate topic in this series of articles.
Prolonged Standing or Sitting
At the same time, a group of workers whose jobs require prolonged sitting in one position are also at risk of developing knee pain. When the knee joint is bent or kept in the same position for a prolonged period of time, it can cause the knee joint to stiffen up. This can lead to pain and swelling in the knee joints. One of the common conditions due to prolonged sitting with bent knees is known as housemaid’s knee or prepatellar bursitis, where the bursa in the knee is inflamed due to prolonged pressure from kneeling or due to frequent strong blows to the knee, for example, scrubbing the floor with forward on the knees. For mild knee pain patients, symptoms may still be bearable with no obvious signs of disability, but the knee condition will worsen over time, and this group of workers will likely suffer from severe knee pain and disability at an earlier age. Hence, it is important for knee pain patients to get treatment early and change the way they work.
Individuals with jobs that require prolonged periods of standing or sitting are at a higher risk of developing knee pain. Long periods of standing put more weight on the knee joint, leading to degeneration of the knee cartilage and the development of osteoarthritis. Walking puts between 3 to 6 times the body weight on the knee joint. Hence, for people working in occupations that require prolonged standing, a healthy knee joint will wear out faster. This has been proven in studies suggesting that knee pain is common in workers who spend the day on their feet, such as construction workers, nurses, and teachers. In contrast to office-based job workers, standing for long periods of time, the risk of knee pain is similar to those working in a job requiring more physical activity, such as frequent kneeling, squatting, and heavy lifting. Therefore, it is crucial for these workers to realize that their knee pain can be due to the nature of their job, and it is essential to relieve the pain, prevent worsening of their knee condition, and educate them in changing the way they work in order to increase the longevity of their knee joint.
Strategies for Addressing Workplace Factors
A comprehensive and specific search occurred using the keywords. Inclusion criteria were that the paper had to be about an intervention or assessment including people 18 years or older with knee pain, an intervention or workplace factors that contribute to knee pain. An occupational setting had to be specified. Massage therapy was also included in the search as it has been shown to be effective for pain relief. Simulation training and mobile spine units were not included initially but after retrieving no papers on the chosen topics, the authors allowed for less specific interventions and assessment to make sure enough information was obtained. Data extraction was done on each paper to find out it was not relevant to factors affecting knee pain and to devise a specific list of types of interventions and assessments which would only include literature on knee pain or knee injuries. This list was: ergonomics, specific exercises or stretches to relieve knee pain or prevent further knee injury, workplace assessments on risk factors, functional testing, and shoe inserts or orthoses. Forty-four randomized clinical trials, eight qualitative or controlled trials and two systematic reviews met the inclusion criteria. The random clinical trials were considered to be level of evidence II and the qualitative trials and systematic reviews were considered level of evidence I. Dropouts in the paper were too high or not specified in three of the trials and although most look at treatment methods there was little or no information on the specific factors of the intervention designed for people with knee pain. One important study investigated fear about the future deterioration of knee pain and its limiting effects with two focus groups of women with radiographically confirmed knee osteoarthritis. Given that there has been little information found on occupational factors centered on knee pain, the authors of this paper are confident that the results of their search has found the majority of useful literature.
Ergonomic Assessments and Modifications
Ergonomics is defined as the study of the relationship between workers and their environment and is acknowledged as an effective tool in the prevention of musculoskeletal injuries in the workplace. The mechanism of anterior knee pain often involves an exacerbation of pain during activities that involve high compressive or shearing forces at the patellofemoral joint. These forces are often generated in positions of knee flexion and/or by the lower limb being subjected to a moment arm or torque. Identification of activities and work tasks that involve these forces and positions is important in targeting aggravating or causative factors of knee pain. This can be achieved by a review of injury and illness records and by consultation with the workforce and can then lead to modification of tasks to decrease their impact on the knee. provide an example of task modification aimed at decreasing patellofemoral joint forces in soldiers. This involved substituting kneeling on one knee position (high patellofemoral joint compression) for sitting on a four-legged stool to do the same task. A sitting job is another example where simple task modification to a different job may be a feasible and effective way of reducing knee pain impact.
This article will now look at some of the effective strategies for dealing with knee pain within the workplace. An injury prevention model to address anterior knee pain in a military training setting was used as a basis for identifying appropriate workplace interventions. These strategies included: ergonomic assessment and modifications; stretching and strengthening exercise programs; workstation adjustments; and alterations to break schedules and job rotation. At present there are no published studies specifically addressing the effectiveness of these strategies in a workplace setting in relation to knee pain. However, studies have shown support for the effectiveness of ergonomic assessments, exercise programs and breaks/rotation on musculoskeletal pain and injury reduction in general. Therefore it is reasonable to infer that these strategies would also be effective in reducing the impact of knee pain in the workplace. Randomised trials evaluating each of these interventions with a specific focus on knee pain in various work populations are needed to confirm their effectiveness.
Stretching and Exercise Programs
Stretching for someone with knee pain is fundamentally different from other injuries and can often cause more harm than good. For example, a common stretch for hamstring flexibility is to place the foot on a chair and lean forward, stretching the back of the leg. This is an unsuitable exercise as it places too much stress and compression on the knee joint. A more suitable exercise would be to sit on the edge of a table and let one leg gently swing, using its own momentum to increase the stretch at the back. This prevents the stretch from becoming too aggressive and is easily controlled. Static stretching exercises should only be held for a maximum of 15 seconds. This is because static stretching has been shown to cause up to a 20% decrease in muscle strength when held for longer than this. Muscle strength may take over 6 hours to return to normal. Flexibility can still be gained through repeated short spells of stretching and is therefore more beneficial for the strength of knee muscles.
Stretching and strengthening exercises are often recommended by knee pain doctor Singapore. Research has shown that individuals who exercise regularly have less pain. However, to be effective and not cause further damage, exercises should be specifically tailored to the individual and changed in accordance with the person’s symptoms.
Workstation Adjustments
Workstation adjustments can be made simply and with minimal cost, yet the results can be very beneficial in reducing knee pain. It has been suggested that higher seated chair heights can reduce the need for deep knee flexion, potentially reducing knee joint loads. However, it has been recommended that if a more upright posture is adopted, the seat angle should be adjustable so that the user can vary between 85-105 degrees at the hip. Changing the angle of the seat pan has also been shown to alter pelvic tilt and ischial tuberosity contact force, which may in turn affect lower limb kinematics and kinetics. Armrests can also be useful to help users get in and out of chairs. This is an important function as increased loads on the patellofemoral joint occur when rising from a seated position. Prolonged standing can also be aggravating to pre-existing knee conditions, joint laxity and post-operative effusions. The installation of a footrest can reduce discomfort and knee extensor electromyography activity when sitting on a high stool. However, if prolonged sitting causes more discomfort then the chair should be changed. With respects to structural changes, if ramps are available then slope angles can be decreased to reduce joint torque and muscle forces at the knee, particularly in loading and unloading activities.
Break Schedules and Rotation
Simulation studies have shown that OA is a developmentally slow process and that progression is not necessarily continuous. This suggests that there could be potential to prevent or reduce knee OA in individuals who are identified as being at high risk. Hence, it is possible that mismatched dissimilar to work as a risk factor for knee OA could be lasting damage to the joint caused by heavy and/or frequent and prolonged loading of the knee.
A recent laboratory study has shown that simple static knee loading can cause pain in individuals with OA. This has implications for squatting and static kneeling work tasks because it is likely that pain could occur during the task being performed. High knee pain prevalence has been noted in miners and floor layers, many of whom are required to work in a static kneeling position.
Break schedules and rotations are a common feature of many workplace environments. However, there may be quality differences between the characteristics of breaks on the three shift systems. It is likely that changing from a two 12-hour shift system to three 8-hour shifts would improve quantitative and qualitative characteristics of off-the-job time by providing more time off and also more frequent long breaks between work periods. Also, implementing three or four teams working 8-hour shifts could offer some advantage in terms of greater time off but possibly less consistency in work and rest patterns.
Collaboration with Knee Pain Doctors in Singapore
The fourth objective is to achieve a durable and sustainable return to previous job tasks. This is especially important for patients who have undergone surgery. The doctor’s involvement will ensure good communication with the employer and the planning of a realistic timeline for returning to previous job duties.
A third objective is to improve the patient’s physical condition. Dealing with occupational knee pain often requires attention to overall physical fitness and weight management. As compared to the average family physician, a knee pain specialist will have a better understanding of fitness and conditioning for athletes and workers with physically demanding jobs. A family physician may advise a mailman with knee pain to take a few weeks off work and give him some anti-inflammatories. A knee pain specialist may recommend a course of physical therapy and advise a strength and conditioning program for the legs, reassuring that it is okay to continue working. A stronger leg will better support the knee joint, and leg strength in patients with knee osteoarthritis has been correlated with decreased symptom progression.
The second is to identify suitable alternate or modified job tasks. This is especially important for patients recovering from recent surgery or serious injury. showed in a study involving worker’s compensation patients that those who were able to resume modified duty had significantly shorter disability and wage loss.
There are four objectives in collaborating with knee pain specialists. The first is to identify the cause of the problem. This will enable the accurate management of the condition and prevent recurrence. By better understanding the problems and demands of a particular job, the doctor can advise the best course of action for the worker. For example, an elderly retiree suffering from knee pain aggravated by climbing stairs may be advised to limit stair climbing as much as possible, while a soldier with the same diagnosis may undergo arthroscopic surgery as he needs to continue with high levels of physical activity.
Diagnosis and Treatment Options
Use of Magnetic Resonance Imaging (MRI) for non-specific LBP is common despite evidence that findings do not change clinical management or outcomes. Knee OA has characteristic clinical and/or x-ray findings to confirm diagnosis. In both LBP and knee OA, the use of allied health interventions before medical assessment is common and may delay optimal medical management. Development of triage algorithms to determine the appropriate time and type of medical assessment have been shown to improve clinical outcomes for specific LBP diagnoses. In knee OA, identification of clinical and x-ray criteria for mild, moderate and severe disease has been used to determine appropriate medical and surgical interventions. An effective approach to identification of diagnosis and severity for LBP and knee OA will result in more timely and specific medical interventions. Tiered pathways based on diagnostic criteria can be developed for each M&MP specialty area to determine the most effective medical intervention and surgical procedures at each stage of disease.
This refers to effective medical intervention in chronic diseases to deliver better clinical outcomes and productive work status. It is essential to develop specific diagnostic and treatment pathways for LBP and knee OA. In the acute stage, a LBP diagnosis may not be possible because of its non-specific nature. However, for those with radiculopathy, zoster, vertebral fracture, spinal infection or spinal tumor, specific diagnosis is essential. This should be followed by rapid referral to an appropriate medical specialist for attention to Red Flags and treatment of the specific diagnosis.
Rehabilitation and Physical Therapy
High-quality therapy and rehabilitation programs, more often than not, are cost-effective in getting the injured worker back to full duties and preventing recurrence of the injury. This will also be useful in the next stage described by employers on the return-to-work plan.
In the event that surgery is required, the individual’s occupation will influence the type and time of surgery (to reduce the time off work) and a realistic time frame for returning to work. This also has implications on workplace compensation and funding for surgery. By engaging local knee pain doctors on what their patients’ needs are, we hope to do a better job of directing patients to the most suitable therapy program. This may also involve developing schemes or information to better inform patients about their condition and therapy options in order to improve utilization of therapy services.
Rehabilitation and physical therapy services in Singapore have, in the past, been underutilized. A study on ACL reconstruction patients found that 76% of patients did not seek the help of a physical therapist after surgery. This is pertinent because different demands on the knee will result in different rehabilitation and therapy programs. An office worker suffering from knee pain may not require a big change in their work duties compared to a construction worker who spends the majority of his day squatting and lifting heavy objects.
Return-to-Work Plans
One essential aspect of our research deals with return-to-work issues and the perspectives of the employees and employers. Our research team is from a tertiary hospital. In Singapore, the employees with knee pain are of older age group as compared to Western countries, where the retirement age is 62-67 years old (as of 2012). This itself is a challenge, as in the current workforce, older employees may have different job demands and may be less savvy in terms of adaptability to modifications at the workplace or the job nature. Additionally, there is a higher prevalence of knee pain in Chinese and Indian population when compared with Caucasians. This takes into account the racial mix in Singapore. These factors will influence the duration of work absenteeism, or whether the employee will stop work altogether and apply for an invalidity status. Keen understanding of the employers’ perspectives and demands are necessary to derive a suitable return-to-work plan for the employees. The time spectrum of return-to-work can vary greatly from one to two weeks after an arthroscopic procedure for a minor meniscus tear, to 3-6 months for those who had major reconstructive surgery for ACL injury. Studies done in the US have shown that the progression of knee pain has a significant influence on work loss, but this has not been addressed in the workplace setting. Usually, the employee will take SL or no pay leave during the surgical period. Determining from the employee as to when to start the clock on formulating a return-to-work plan is quite nebulous. The employers will have different perceptions from our recommendation, being afraid that a premature return may potentially affect productivity or medical cost. This itself can create tension and conflicts within the employment relationship.
