Patellofemoral pain syndrome is a term used to describe pain at the front of your knee, or around the kneecap. The cause of this pain is generally associated with the Patellofemoral joint. This is where the kneecap (patella) connects with your thigh bone (femur).
In younger people, pain around the patella is generally associated with the inflammation, softening or tearing of the cartilage that sits in between the kneecap and thigh bone. In older people, the pain usually occurs due to wearing or degeneration of the cartilage in between the kneecap & thigh bone.
- Pain usually worsens with activity, or towards the end of the day/activity. Activities will involve bending/straightening of the knee (e.g. lunging, squatting, walking up/down hills, kneeling)
- There may be popping or cracking noises, and you may feel grinding of the joint.
- The knee may lock at a certain range or have a feeling of giving way.
- Pain settles down with rest.
Risk factors vary on a case by case basis, but similar risk factors will contribute to patellofemoral pain in both younger and older populations
- Q Angle: The Q angle refers to the angle between the pull of the quadriceps muscle relative to the patella tendon (this attaches vertically from your knee-cap to the top of your shin bone). The Q angle is affected by the width of the hips, as well as the alignment of the hip joint. A higher Q angle means that the kneecap is more predisposed to moving sideways compared with a lower Q angle. More sideways movement means that there is more change of irritating or causing wear and tear of this knee cap joint.
- Knee Valgus: Knee valgus refers to when the knee joints cave inwards. This occurs when the angle between the thigh bone and knee bone increases. A conventional term for knee valgus is “knocked knees”. Knee valgus can contribute to patellofemoral pain syndrome as the contact surfaces between the kneecap and the thigh bone can change and the pull of the quadriceps muscle on the kneecap predisposes it to more sideways movement.
- Tibial Torsion: Tibial torsion refers to the alignment of the thigh bone and shin bones based on the way they rotate on each other. When the shin bone is rotated outwards relative to the thigh bone, there are increased sideways forces placed on the kneecap. This is one of the biggest factors contributing to kneecap related pain.
- Hip & Ankle Alignment: There may be variations in the way your hip or ankles are aligned, especially during movement. These may affect the alignment of your knee during movement, even if none of the 3 factors mentioned above are noted during a physical examination.
- Muscle Weakness: The quadriceps have a direct connection to the kneecap and are responsible for controlling its movement and alignment over the knee. Weakness of the quadriceps affects the kneecap alignment, and potentially knee alignment too. Weakness will present differently in everyone, and relative based on the requirements of sport or work.
- Overload/ overuse- Excessive running or jumping sports puts repetitive stress on your knee joint, which can cause irritation under the kneecap. Sustained sitting with the knee in the bent position can also irritate the patella-femoral joint(movie goers knee).
ManagementA physiotherapist will manage your condition by:
- Releasing tight muscles or soft tissue around the knee/ankle joint.
- Provide pain relief through use of hot/cold packs (depending on when the knee pain was last irritated), and electrotherapy.
- Mobilise the kneecap joint or knee joint to reduce stiffness or improve the patella’s contact with the thigh bone.
- Taping the patella to improve the way it is aligned with the rest of the knee joint.
- Advising you on how to manage relapses or exacerbation of pain, and how you can gradually return to full activity. For sports people load management is important in controlling the condition.
- Strengthen or lengthen the muscles around the knee – specifically the quadriceps
- Improve proprioceptive feedback at the knee – the awareness of your knee joint in space
- Co-ordination for sports/work specific movements/skills
- Agility/Plyometric based exercises with emphasis on appropriate knee alignment.