Aching at the front of the knee is one of the most common presenting symptoms in athletes. It is typical in children and more common in girls than boys.
The two most common causes of anterior knee pain are
- Patello-Femoral Syndrome
- Patellar Tendinopathy
Diagnosing these conditions can often be difficult as they often have similar symptoms, and can even present together. The patello-femoral joint is formed by the knee cap (patella) sitting on the front of the thigh bone (femur).
As the knee bends, the patella moves in a groove found at the end of the femur. The patella is a floating bone. Therefore, the patella’s position and function depend intimately on the structures that attach to the patella. This is important to remember when we discuss treatment and management.
Patellofemoral Pain What is it?
Patello-femoral pain occurs when the under surface of the patella (knee cap) is pain sensitive, due to damage and irritation to any of the pain sensitive structures between the patella and femur. This can be caused by incorrect tracking, or movement of the patella, as the knee bends and straightens. The patella rubs against the femur, instead of gliding correctly in the groove.
What causes it?
Remember the patella is a floating bone. Therefore, structures that are too tight will pull the patella into the wrong position. Usually the tightness occurs in the lateral thigh structures (tensor fascia latae, gluteals, quadriceps, hamstrings, calf) and a loss of muscular control (and strength) of the inner quadriceps muscle, the vastus medialis oblique (VMO). Typically, the ‘tug-of-war’ between the outside and inside structures is won by the outside, pulling the patella laterally. Eventually, too much incorrect rubbing leads to inflammation, pain, swelling and dysfunction (ie difficulty walking down stairs and hills). What are the symptoms?
- Pain that gradually worsens with activity i.e. running
- Pain going up or down stairs
- Pain with squatting
- Pain with prolonged sitting (movie-goers knee)
- Pain deep in the front of the knee
- Giving way or a feeling of instability
- Recurrent clicking What can be done? A thorough physical and biomechanical assessment, including functional testing to reproduce the patient’s pain and locate the nature of the symptoms is required.
Physiotherapy management is based on scientific research led by physiotherapists. Treatment concentrates on improving the control of the patella, leading to a successful recovery and return to sport.
This will include:
- Relative Rest: inflammation must settle for motor control to improve
- Minimise inflammation: regular application of ice will provide pain relief. Anti-inflammatories prescribed from your doctor may also assist at this time.
- Taping: of the patella to correct abnormal patellar position, will minimize pain and facilitate the contraction of the VMO / quadriceps muscle.
- Massage: plays an important role in allowing the lateral structures to stretch by ironing out any tight knots.
- Foam Roller and Self Trigger Point Management: self massage at home will help improve the effects of stretching and restore muscle function and alleviate tightness
- Increase Strength: of the VMO, to improve the control of the patella, and pelvic stabilisers (i.e. gluteal muscles of the buttock), to minimise the load on the patellofemoral joint.
- Correction of Pre-Disposing Factors: this ensures that the problem doesn’t re-occur and can include advice on training principles (overload and recovery) and biomechanical issues such as lower limb mechanics including foot posture and function:
Patella Tendinopathy In the past this injury was labelled ‘patella tendonitis’.
Tendonitis suggests inflammation of the patella tendon, however recent clinical research has more accurately termed it ‘patella tendinopathy’. Histochemical examination indicates that there are few if any inflammatory chemicals in the patella tendon when it has pain and dysfunction. Hence the name change to tendinopathy. What is it? Patella tendinopathy, or ‘Jumper’s knee’, refers to a painful overuse injury of the patella tendon, which connects the kneecap (patella) to the shin (tibia). This occurs as a result of degeneration (either acute or chronic) and a ‘weakening’ within the patella tendon itself, without the presence of inflammation. Many cases of patella tendinopathy also co-exist with patellofemoral syndrome.
What causes it?
It is caused by excessive loads on the patella tendon, particularly if there are insufficient rest periods. It is most commonly seen in athletes that engage in running and jumping type sports, such as netball or basketball. What are the symptoms?
- pain is well localised (from a dull ache to severe and sharp) at the front of the knee
- anterior knee pain is usually of a gradual onset
- jumping and landing activities will increase the pain
- the bottom of the patella will be tender to touch
- pain will occur with squats and stairs, particularly descending
- below the patella can be swollen, or ‘puffy’, but this is rare
- unlikely to be episodes of giving way or instability What can be done? Rehabilitation is a lengthy process and the athlete may take from 3 – 6 months to return to sport. This may include:
- Rest / Ice: Reducing your activity levels and regular periods of applying ice is essential to prevent the patella tendon becoming more sensitive and painful.
- Taping: of the patellofemoral joint should be used if it is contributing to the symptoms. Taping the patella tendon itself can also assist in reducing the load on the tendon.
- Massage: is performed on the patella tendon to improve local blood flow and release adhesions between the collagen fibres that compose the patella tendon. Often other thigh structures (quadriceps, iliotibial bands) will also need to have any trigger points resolved.
- Stretching: poor hamstring and quadriceps muscle flexibility can overload the patella tendon. Hence, a regular stretching program, particularly in ‘growing’ children, is essential.
- Increase Strength: a quadriceps strengthening program is needed to increase the tensile strength of the patella tendon. This involves a graduated series of exercises, that start slowly, and then progress by increasing the speed and weight involved during exercise.
- Correction of Pre-Disposing Factors: as already outlined in ‘patellofemoral pain’ above, these changes ensure that the problem doesn’t re-occur in the future.
- Surgery: if conservative management fails, then surgery can be a possibility with long-standing patella tendinopathy. Further investigations (ultrasound, MRI) can assist in determining whether surgery is required. The rehabilitation process is slow and lengthy, following the principles outlined above. A return to sport is approximately 6 – 12 months, with only 60-75% of patients returning to their previous levels of sport.