The swelling leads to an increase in knee pain, which in turn leads to more knee pain in future menstrual cycles. Progesterone is another hormone that has been shown to have an effect on knee pain. In a study, it was found that women who developed ACL injuries during their ovulatory phase experienced a lower occurrence of giving way in the knee when compared to women who sustained their injury during other phases. However, the same study found that there was no significant difference in knee stability among the different menstrual phases. The exact method by which progesterone influences knee pain and knee stability is not yet understood.
Pain in women often worsens in association with menstrual periods, and one of the common tools to help diagnose PFS is a hormone test. A high level of estrogen has been shown to have a direct effect on the severity of PFS, especially increasing the amount of patellar swelling after the occurrence of an injury. Studies have shown that there is an increased ratio of females to males who have developed PFS. This increased ratio is postulated to be primarily due to the high level of estrogen in women. This evidence supports the theory that hormonal changes in women, specifically high levels of estrogen, are a cause of PFS. Unfortunately, the increase in patellar swelling caused by elevated levels of estrogen may create a continuous cycle.
Hormonal Factors
Although these hormonal and anatomical determinants may place females at increased risk for knee problems, it is clear that female athletes are at particularly high risk. In knee pain Singapore, females participate in netball, and in many cases, soccer and basketball, in numbers equal to or near those of their male counterparts. Netball, in particular, is a sport involving sudden stops and sharp manoeuvres, placing tremendous forces on the knee in a predominantly female population. Studies have consistently shown that female athletes participating in sports involving jumping and cutting manoeuvres are at significantly higher risk for ACL injuries. These risks for the development of specific knee problems in the female athlete are best examined in the context of gender-specific differences in knee mechanics.
Estrogen modulation of the immune system and the repair of connective tissues may be an explanation for the higher prevalence of knee injuries, and in particular, the remarkably higher incidence of ACL ruptures in females compared to males. Recently, researchers have also discovered that females tend to have a larger Q angle due to the fact that they have wider hips. This larger Q angle may put more stress on the knee and increase the likelihood of sustaining an injury. Whether or not hormonal replacement therapy may mitigate these risks is unclear, and at present, the potential adverse effects of such therapy are believed to outweigh any potential protective benefits. Future work on the hormonal modulation of these mechanisms will help to better understand the implications and may point the way to preventive interventions.
Biomechanical Differences
Smaller hamstring size and higher estrogen levels are possibly a reason for slower activation of the hamstring muscles in women. In response to anterior tibial shear, estrogen may inhibit the hamstrings’ protective role of stabilizing the tibia. This inhibition, combined with delayed muscle firing and lower levels of co-contraction of the hamstrings, leaves the ACL vulnerable to injury. Consequently, the higher rate of ACL injuries in women compared to men may be related to differences in neuromuscular function and hormonal factors.
Women have smaller and weaker hamstrings in comparison to their quadriceps. The hamstrings to quadriceps strength ratio is 50% lower in women than in men. This imbalance is believed to be a significant factor in knee injuries. During eccentric muscle contractions, the hamstrings act to decelerate movement. When suddenly changing direction or landing from a jump, the quadriceps quickly contract eccentrically to control knee flexion and it’s during this phase of movement that the hamstrings often fail to generate an adequate force to counteract the pull of the quadriceps. This strength difference is also believed to be a contributing factor to ACL injuries.
Women have a greater quadriceps angle (Q angle) than men. As a result, the pull of the quadriceps on the patella is more lateral in women and more axial in men. This increased Q angle in women is believed to be caused by wider hips. Increased valgus at the knee also occurs, most likely as a compensatory mechanism to allow women to stand with their knees locked in extension, using less muscle force to support body weight. This knee alignment places excessive tension on the medial patellofemoral joint, possibly leading to PFPS.
Lifestyle Factors
It is said that “we are what we eat.” Many orthopedic problems in modern society, some of which affect women more than men, are born from a poor diet and overweight. Eating a lot more calories than a woman can burn can lead to weight gain. This additional weight can be harmful to the knees. Knees carry the brunt of the body’s weight, and the more weight that is put on them, the more likely they are to become damaged. Even a small increase in weight can increase the risk of cartilage breakdown in the knee and the risk of osteoarthritis. Obesity rates are on the rise in Singapore, especially in women. It is estimated that over a 1/4 of adult women in Singapore are obese or overweight. Women are taught from a young age that being slim is beautiful, and many feel increased pressure to diet and stay thin. Unfortunately, many popular “modern” weight control diets are unhealthy and may lead to an increased risk of knee problems. Some health conditions related to diet can also be harmful to the knee. Diabetes, for example, can cause damage to the nerves in the body, which can lead to a weakened state and a higher risk of injury. High blood pressure and high cholesterol can also add to the risk of knee cartilage breakdown. A good diet and regular exercise are the keys to maintaining a healthy body weight and avoiding these and many other health problems. Eating right and staying active in the right ways keep the whole body, including the knees, strong and healthy.
Diagnosis and Treatment Options
Due to the number of different issues that may cause knee pain in females, and the fact that many patients have more than one painful area or a combination of several pain generators, the medical evaluation can sometimes be quite involved. A detailed history is essential for the physician to begin to understand the patient’s primary concerns and the impact of the painful condition on the patient’s quality of life. Anatomic location and pain type are important elements of the history that can give the physician some preliminary understanding of the patient’s pain generators, and it is important for the physician to elucidate an onset and/or functional aggravating factor for the painful condition. A history of giving way, swelling, or mechanical symptoms can give insight into the possibility of intra-articular pathology and is important information for diagnosis and treatment planning. Mental health and coping mechanisms are also important issues in the patient’s history, as chronic pain can significantly affect a patient’s psychological well-being, and a patient’s ability to maintain a positive outlook and continue to self-manage their condition is paramount to treatment success. A history of medication usage, previous treatment, and response to previous treatment can also guide the physician’s decision-making for current and future treatments. Finally, a good understanding of the patient’s occupational and recreational demands can help the physician tailor treatment options to best suit the patient’s lifestyle and activity level.
Musculoskeletal pain evaluated as a chief symptom is one of the most common complaints in medicine, regardless of the patient’s age, gender, or ethnic background. Because musculoskeletal pain can arise from a wide variety of causes, successful evaluation and treatment can be challenging. Knee pain is often multifactorial in etiology, and female patients may have issues that are unique from those experienced by males. Successful treatment of knee pain in female patients depends on understanding both the typical causes of knee pain and the common issues and concerns that are unique to the female gender.
Medical Evaluation
The physical examination is the most significant part of the medical evaluation. The physical examination consists of two steps to correctly identify afflictive knee conditions. These steps are observation and palpation. During the observation, the knee pain specialist inspects the knee for any abnormal alignment of the leg and any atrophy in the muscles above and below the knee. Any abnormal alignment suggests that there is ligamentous damage in the knee. This could be an acute injury such as a ligament sprain or a chronic injury such as a ligament tear. An MRI would be needed to diagnose the acute injury, and a chronic injury would be substantiated by the decreased integrity of the ligament on a physical examination using the Lachman’s test. Atrophy of the thigh muscles may indicate a serious knee problem or be a result of disuse. In chronic and aggressive knee arthritides, the quadriceps muscles often are found to have an abnormal degree of atrophy. An MRI is effective at diagnosing most arthritides and will be able to delineate the causative factors for muscle atrophy. Lower on in the exam, the observational findings are used to assess the patient’s function of the knee affected and to predict any special tests that may be done later on in the examination. The second part of the physical exam, palpation, is done to elicit a specific reaction from the patient that aids in the diagnosis of a particular knee condition and to feel for any signs of inflammation in the knee. By palpating areas specifically around the knee joint, the doctor is able to test for pain and signs of inflammation. This method is used to confirm a suspected diagnosis from the medical history. An example of this would be the test for a meniscal tear. In a patient with mechanical symptoms of catching or locking of the knee, the exam will try to produce these symptoms by palpating the area of the joint line of the affected knee. Any pain or catching is suggestive of a meniscal tear that may require arthroscopic surgery. Other diagnostic tests that are done during the physical examination are specific to the existing symptoms of the patient. This part of the examination serves to confirm diagnosis that has already been done from the previous steps. For a patient with swelling of the knee that prevents normal function, a patellar tap may be performed to confirm a suspected diagnosis of rheumatoid arthritis which is causing an effusion of the knee.
Non-Surgical Treatments
An adequate examination by a physiotherapist or a supervised athletic trainer with instructions in a home-based program is a successful way to reduce knee pain. The program should consist of strengthening, coordination, and functional training parts combined into one specialized exercise program. There should be close supervision of the program for at least three times per week over an eight-week duration. This kind of program will have effects on all forms of knee pain. It can prevent pain if it is not present, decrease or eliminate current symptoms, and it is the most effective way to prevent recurrence. There have been many studies promoting the use of bracing and/or taping for those people with signs of knee instability, especially in those individuals with ligamentous laxity. The purpose of bracing or taping is to restrict abnormal knee joint movement and potentially prevent the onset or progression of degenerative knee issues.
Beginning a non-surgical treatment for women who may experience knee issues can be safely managed non-operatively. The aims of the non-operative treatments are to decrease pain, increase function, and improve patient satisfaction. Activity modification is suggested for those patients with pain connected to a specific activity from which they are unable to abstain. Weight loss is suggested because studies have clearly shown that weight loss is connected with significant pain relief in 30% of overweight people. Physical activity is the cornerstone of non-operative treatment for knee pain.
Surgical Interventions
These observations suggest a need to develop better guidelines for therapeutic decision-making in knee disorders in general and for surgery in specific. Key elements to this process are identification of factors leading to adverse outcomes such as pain and loss of function, clarification of differences in structural and functional deficits among affected populations, and development and testing of interventions targeted at the identified factors. This is an area ripe for clinical and epidemiological research, using both observational studies and relevant RCTs.
Surgery affects a greater proportion of women with knee disorders than men, its peak use being in the age range of 45 to 64 years. This is true in spite of the absence of information on the effects of many procedures in women and on the best indications for surgery. It is known that certain procedures performed to a greater extent in women than men, such as arthroscopically-assisted anterior cruciate ligament reconstruction and arthroplasty, carry good potential for relief of pain and improvement in physical function. However, many procedures are done primarily to alleviate mechanical symptoms, without strong evidence that they will alter the natural history of the disorder or prevent functional decline. In addition, there is evidence that elderly men and women with similar knee radiographs and symptoms represent subgroups with different structural and functional deficits.
Given the continuing painful experiences and missed social and recreational activities reported by women with knee disorders, it is important to provide appropriate treatment.
Prevention and Management Strategies
Patients with patellofemoral pain, osteoarthritis, and ligamentous injuries can benefit from physical therapy, which can include a variety of modalities and exercise programs. McConnell has demonstrated that patients with acute onset and chronic patellofemoral pain can be effectively treated with patellar taping, bracing, and foot orthotics. A recent systematic review of the literature has shown that exercise is effective in reducing pain and improving physical function with knee osteoarthritis. Several modalities, including cycling, aquatic exercise, and strength training, have been shown to decrease pain and improve physical function in adults with knee osteoarthritis. Strength training has had a consistent and substantive effect on the improvement of pain and physical function, and quadriceps strengthening with isometric exercise is effective in decreasing pain in osteoarthritis. High intensity and long-term exercise programs have been effective, and the effects of exercise in osteoarthritis are long lasting. Similar results in pain reduction and functional improvement have been found among aerobic, resistance, and performance exercise programs. Static and dynamic progressive resistance programs have been shown to effectively aid patients with less severe osteoarthritis. Finally, exercise effects were sustained after the completion of the programs in the absence of adverse effects on pain or joint safety.
Prevention and/or management strategies for knee pain usually depend on the source of the pain and the lifestyle of the person. Regardless of one’s knee pain is derived from, weight loss should be strongly considered as a primary factor. The effectiveness of weight management can be measured simply by loads on the knee joint. Losing a little weight can decrease a large amount of joint load. For instance, research has shown that losing 11 pounds of body weight decreases knee pain in people with osteoarthritis. Each pound of weight loss results in a 4-fold reduction in load exerted on the knee for each step taken. Patients who are advised to lose weight for knee pain should be instructed to adopt strategies that combine diet and exercise under the supervision of a health professional. Weight loss achieved through diet can be effectively facilitated by consultation with dieticians, and it is a cost-effective way to reduce joint load.
Exercise and Physical Therapy
The ability to be active and exercise is related to work status, socioeconomic factors, access to facilities, and environmental determinants. Understanding and promoting physical activity is a complex issue and requires behavior change at individual, community, and societal levels. Global initiatives aimed at prevention and management of chronic conditions such as non-communicable disease will have an effect on knee pain in the future.
Exercise-based therapy can include various types of stretching and strengthening exercises, neuromuscular education, and proprioceptive training. There is increasing evidence to show the importance of the latter two. Traditional exercise and physical therapy can be done at home or supervised by a therapist, and newer methods are emerging such as hydrotherapy and tai chi. Both of these methods have been shown to be beneficial in osteoarthritis. High-quality evidence from a number of trials shows a short-term benefit of acupuncture in relieving knee pain and improving functional status. No study has found an increased risk of adverse effects for exercise therapy in knee pain.
Pain has a major effect on functional performance and results in avoidant strategies and disuse of the affected area. This may lead to muscle wastage, reduced muscle strength, decreased proprioception, and poor joint position sense. All of this is a risk factor for the progression and increased severity of the initial condition. Pain relief and improved function are essential in the management of knee pain, and this is sometimes used as a treatment goal in itself. Regular moderate exercise has been consistently proven to be one of the most effective interventions for long-term pain relief and improved functional status. It can be cheaper than drug intervention and results in fewer visits to the healthcare provider. There are a very large number of trials and therefore evidence for the beneficial effects of exercise in many different knee conditions, and it is particularly beneficial in osteoarthritis and after certain surgeries. There is no direct comparison on efficacy between different types of exercise or between exercise and drug treatments, so these will be choices made between the individual and the healthcare provider. It is to be noted that some people with acute knee injuries may not experience an exercise-based intervention until later in their rehabilitation phase. A systematic review has shown a benefit of exercise therapy in the treatment of osteoarthritis, which is only moderate in comparison to a placebo control.
Exercise suffers from poor compliance rates in the western world. People do not exercise enough, and the levels are even lower in persons with chronic illnesses and disabilities. Knee pain is no exception, and reliance on medication can be one of the barriers to exercise. Smokers are an example of a hard group to get to exercise. Advice to stop smoking is likely to be more successful and may indirectly lead to increased exercise. A US study has looked at the ability to walk in older persons with the onset of recent knee pain. People who develop mild, moderate, and severe levels of knee pain have all been found to subsequently reduce the distances that they are able to walk. However, increased pain is not associated with decreased walking speed, strength, or balance.
Weight Management
Anti-gravity treadmills and aquatic therapy are other good options. Elliptical machines or cross country skiing machines, stair climbing machines, for aerobic conditioning. These machines will not stress the knees if they are set on the proper resistance and intensity. For strength training, machines are generally better than free weights for targeted muscle strength/endurance training. High rep and low resistance is usually best for people with most any type of knee problem. Supervised exercise therapy has the added benefit of the patient’s own commitment to the program. Group therapy and exercise may improve patient’s compliance with treatment protocols. Supervised physiotherapist-led exercise programs can result in patient symptoms improving by 42%, function by 45%, and decrease disability by 59% compared to unsupervised home exercise programs. Tai Chi or Qi Gong are suitable for elderly people with knee pain due to OA or chronic knee pain. Both are low impact and can improve gait, leg strength, and balance, abilities which may prevent the onset of knee pain in the future.
Joint Protection Techniques
The use of assistive devices has been shown to be the most effective strategy for reducing pain and even the number of total joint arthroplasties performed on a particular joint. While joint arthroplasty is a reasonable option, if this can be delayed, there are many benefits to maintaining the integrity of the native joint, and an assistive device can provide this. For any use of an assistive device to be successful, there must be a positive attitude by the user, and importantly, the device must be the most appropriate choice for that individual, the task, and the environment.
Functional use of the hand and upper extremity joint position should be observed with the appropriate use of adaptive equipment and devices. Often an individual who has an acute condition or flare-up of their joint ROM does not have available equipment to assist them with their daily activities, and the lack of this equipment further exacerbates their condition.
Stress Distribution: Joints can be protected by modifying the position or the way an activity is performed so that the stress on the joint is minimized. The load on the knee can be reduced if that person sleeps with a pillow under the knee. If a patient is suffering from osteoarthritis of the hip, they may avoid bending the hip past a right angle. Use adaptive equipment that makes it easier to perform a particular task.
Energy conservation is the principle which involves the distribution of weight during activity so that minimal efforts are required to perform that activity. This can be achieved by using a trolley during shopping, trying to sit as much as possible, and avoiding lifting heavy material. It can be accomplished by simplifying tasks, receiving help to do tasks, and avoiding or interrupting tasks causing pain. Take more rest breaks during activities. Alternate heavy tasks with lighter ones. Get help from family, friends, and co-workers.
Joint protection techniques are the strategies which can reduce load on joints and prevent them from being damaged. Different joint protection techniques include energy conservation, stress distribution, performance of alternate methods or operations, and use of assistive devices.
Supportive Devices and Braces
Unloader knee braces can be very effective for WOMAC pain – the trial data is very good. Anecdotally, patients feel that their knee is more stable, and there may be a biomechanical unloading effect which is hard to quantify objectively. In my experience, they are well tolerated as long as they are well fitted and patient compliance is good. The same is true for other ligament unloading braces, though this is more relevant to meniscal injury. Patellar taping is a cheap and simple way of offloading the patellofemoral joint, though some patients can develop an irritant dermatitis with long-term use. Most of these devices can be assessed by physiotherapists, but input by an orthotist is often helpful, particularly when looking at more complex devices. Step in rigid offloader braces, and there is an increasing need for medical expertise in determining the nature of malalignment and the specific ligamentous damage. These devices, particularly when tailor-made, are expensive, and if the evidence base is weak, the cost effectiveness comes into question. High tibial osteotomy unloads the medial compartment of the knee and is effective in the earlier stages of osteoarthritis with malalignment. The indication for osteotomy is based on the weight-bearing line on a long leg x-ray – if it is medial to the center of the tibial plateau, there is increased medial compartment load, and the patient is a candidate for osteotomy. Randomized trials have shown it to be effective in relieving pain in the short and medium term, but the long-term results are variable.
