Patellofemoral pain is one of the most common knee conditions affecting a range of people from young athletes to the elderly. The kneecap is named the patella, this articulates with your thigh bone (femur), creating the patellofemoral joint.
The core criteria for defining patellofemoral pain is pain around or behind the patella, which is aggravated by a weight bearing activity that loads a bent knee, such as; squatting, stairs, walking, running and hopping.
Additional symptoms may include;
- grinding sensation emanating from kneecap when bending the knee
- tender along sides of patella
- small amount of swelling
- pain on sitting, rising from a chair or straightening the knee following sitting
Studies indicate a prevalence of 12% in men and 15% in women, and in adolescents 7-28%, although some research indicates it may affect 25% of the population at some time in their lives. This is more common in the sporting population and can sometimes be called runner’s knee.
The most common causes of patellar malalignment are an abnormal muscle imbalance and poor biomechanical control. This is evident in the quadriceps muscle (front of thigh), the outer portion (vastus lateralis) is stronger and more dominant than the inner portion (vastus medialis obliques). This pulls the kneecap outwards and causes it to track laterally in the groove.
The hip muscles are extremely important in knee positioning, especially your gluteus medius (mid buttock muscle). There are a group of buttock muscles that are responsible for rotating the entire leg, if these are weak this may cause the knee to drop inwards.
Exercise therapy: a program specifically tailored to addressing any muscle imbalances with emphasis on correct alignment and technique should be undertaken. Exercises should target the leg and hip/pelvis muscles. Evidence shows that exercise improves pain and function in the short and long term.
Combined interventions: the physiotherapist may use techniques to address muscle overuse, these may include deep tissue massage, dry needling, foam rolling, and mobilisation. Decreased lower back mobility may also place strain on the knee joint, this can also be addressed with mobilisation and exercise.
*Remember the techniques mentioned above will likely only provide short term relief, the long term effects come from addressing the underlying alignment issues with exercise.
Foot orthoses: these can reduce pain in the short term if foot alignment is a main causative factor.
People with patellofemoral pain may also develop OA. Risk factors for this include muscle weakness especially in the quadriceps and gluteals, abnormal biomechanics and alignment. Specific exercise can assist in correcting biomechanics and muscle strength issues.
Patellofemoral pain treatment must be tailored to each individual to address the underlying cause. Evidence shows that specific exercise is the most effective intervention, so you will need to do some homework!
2016 patellofemoral pain consensus statement from 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient reported outcome measures. British Journal of Sports Medicine. Crossley et al 2016.
Part 2: recommended physical interventions (exercise taping bracing foot orthoses and combined interventions). British Journal of Sports Medicine. Crossley et al 2016.