What is Knee Pain ?
Many people are referred to a Physiotherapist because they are experiencing non-traumatic knee pain and I have seen a fair few in my time. However, it can be a mistaken belief that Physiotherapy is the answer to all kinds of knee problems.
Tendonopathies are conditions mainly affecting the tendon of the quadriceps muscle. This may be a tendonitis (inflammation) or a tendinosis where the tendon had started to undergo degeneration. Tendonitis can be caused by excessive explosive activities, using the muscle in a way it is not designed, for example poor posture or indeed embarking on an activity which could cause direct trauma to the tendon for example repeatedly kneeling down on a hard surface without wearing knee pads. Constant abuse of the tendon could eventually lead to a degradation of the integrity of the tissue causing it to malfunction. Typically, this condition can cause pain with any activity requiring a contraction of the thigh muscle and could cause discomfort when the tendon is stretched. Over time the muscle contraction will become weaker as the increase in pain will reduce the effort required for a good contraction.
There are a number of reasons why knee pain may exist. Examples of these reasons are listed below;
Osteoathritis recognised to be a type of degenerative change that affects big weight bearing joints. Joints going through this type of change may be sore, swollen, look ‘red’ or ‘angry’, feel hot at times and have reduced range of movement. Patients sometimes complain of morning stiffness/discomfort that eases the more mobile they become and in later stages of the condition they do report a lot of ‘noise’ coming from the joint during activity. It is not usually a condition that starts as a result of a traumatic incident. It is important to understand here that this is not a bone condition but a Joint one.
Bursitis is an inflammatory condition affecting a ‘pad’ at the front of the knee just below the knee cap. This pad is designed to protect the knee when it is knelt down on. It has also been referred to as ‘housemaids’ knee’. Although this condition may produce the same kind of discomfort as osteoarthritis, bursitis produces a localised area of tenderness and swelling. It is not usual for such patients to describe morning stiffness but walking and kneeling down can be a problem.
Chondromalacia Patella is a condition affecting the under surface of the knee cap. Contrary to belief, the knee cap is not a flat bone but more like a squashed diamond with the pointed section riding up and down a groove located in the lower end of the femur or thigh bone. When there is friction between the patella and one of the sides of that groove the smooth surface of the patella becomes rough and the cartilage becomes softened(1). This condition can be caused by activities involving prolonged bending of the knee(2). Patients complain of pain and discomfort during activity irrespective of the time of the day and they are unable to contract their thigh muscles without discomfort but do not experience any pain when at rest. They may also like the later stages of osteoarthritis complain of ‘noise’ coming from the knee during activity.
Patellofemoral Malalignment is a condition which may cause non-specific pain in the knee. This is a structural problem in which the position of the knee cap (patella), as the name suggests, is not aligned with the natural movement of the knee cap during contraction of the thigh muscles. The difference in the position to the expected is known as the ‘Q’ angle and is greater in females than males(3) by virtue of their naturally wider hips. It can be reason for recurrent patella dislocation. This condition typically can cause pain when walking down slopes and stairs, jumping, hopping, kneeling, running, squatting and prolonged sitting tasks. It can be detected by sitting on the floor with the knee stretched out and flat against the floor and feeling the amount of pressure against the index fingers as they are placed on either side of the patella whilst a strong thigh muscle contraction is made. The pressure should be similar on both fingers. Unequal pressure is caused by the patella shifting more towards that side. This is typically towards the outside aspect of the knee.
Osgood-schlatter’s syndrome is when the tendon of the quadriceps (thigh) muscle attaches to the tibia (shin bone) at an angle. The point of attachment can be felt if you run your finger along the ridge of your shin bone upwards towards the knee until you feel a ‘bump’ known as the tibial tubercle. This bump can be extremely sore to touch and may feel much bigger than the one on the other leg. It may feel slightly warm to touch and may feel spongy where there may be swelling. Any activity requiring contractions of the thigh muscles will be painful. It usually affects males more than females and occurs most frequently during the ages of 9 and 16; the growing period of adolescence.
Genu valgum and genu varus otherwise known as ‘knocked knees’ and ‘bow legs’ respectively.
Both these conditions are ‘structural’ and in most cases naturally occurring to some extent. The severity of these conditions depends upon the degree of angulation from the norm. Genu varum can be acquired from osteoarthritis in the later stages and from bone diseases such as rickets, infections and tumours. Genu valgum can be caused by several underlying bone conditions but most strikingly this can be caused by obesity. Genu varum may cause pain on the inside aspect of the knee which is usually worse when walking long distances or when in a crouched position for long periods of time. Sometimes there may be a feeling of warmth in the area of tenderness and ‘noise’ within the joint during weight bearing activities. The knee may also appear to be ‘puffy’ on the inside aspect of the joint line. There may be a sharp pain on the outside aspect of the knee when walking. Similarly, Genu valgum may cause the same kind of symptoms but this is usually felt on the outside aspect of the knee and the pain is worse with standing for too long rather when in the crouched position. Both conditions put excessive pressure on individual components of the knee structure.
Pes Planus or ‘flat foot’ is a condition where the foot has lost its natural arch support. The arch structure of the foot provides a means of ensuring that the vast weight of the body is managed through the relatively small structure of the ankle. To do this the arch creates a shape similar to a tripod system that allows the 50% of body weight that each leg experiences to be split safely three ways through the foot; 1/3rd through the heel, 1/3rd towards the little toe and 1/3rd towards the big toe.
Most of us have some semblance of flat feet as some of us have some hard skin on the ball of the foot either under the little or big toe or on the heel. This hard skin is evidence of excessive pressure. In most cases this does not have any major effect other than frequent trips to a chiropodist but occasionally the problem will be severe enough to cause the middle of the foot to roll inwards causing the shin bone to rotate inwards and thus cause tension within aspects of the knee joint. The condition causes pain and discomfort during activity and the symptoms are usually similar to that of Osgood-schlatter’s syndrome as previously described.
The above conditions are some of the main reasons why some people develop unexplained knee pain and seek help. A common misconception is that Physiotherapy and exercise will be the answer and unfortunately some of my colleagues will attempt to treat theses conditions without reflecting on the underlying cause. If the underlying cause cannot be rectified then of what use is Physiotherapy intervention? All too often these patients have a very poor outcome to treatment and then feel that Physiotherapy in general is little more than a waste of time.
Physiotherapy can only change the mechanical behaviour of the constituents of the body structure THEY CANNOT CHANGE STRUCTURAL CHANGES. Therefore before you are referred for treatment of any knee pain with an underlying cause involving any of the above always ask for what the expected realistic outcome is. If your problem is linked to pes planus, genu varum or genu valgum for instance ask to see a PODIATRIST. If you do not know one, ask your Physiotherapist who may have a useful phone number. Remember your Physiotherapist is not superhuman! Please do not purchase any item of the shelf that is supposed to be designed to correct the above conditions without first seeking advice from your Physiotherapist or Podiatrist; this is not about seeing you and saying ‘kerching!’
(1) Whiting, W. C. & Zernicke, R. F. (1998). Biomechanics of musculoskeletal Injury. Human Kinetics, USA.
(2)Callaghan, M. J. and Oldham, J. A. (1996). The role of quadriceps exercise in the treatment of patello femoral pain syndrome. Sports Medicine. 21, 5, 384-91.
(3)Aglietti, P.; Insall, J. N.; Cerulli, G. (1983). Patellar Pain and Incongruence: I: Measurements of Incongruence. Clinical Orthopaedics & Related Research. June, 176:217-224.
© Dr A. A. Aluko, March 2013
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