Patellar subluxation or dislocation is defined by partial or total dislocation of the patella, respectively. It is more common in young, active individuals, and occurs most often externally. It is associated with pain in the acute setting and possible evolution to recurrent instability and other consequences in the long-term, such as osteoarthritis and impairment of knee function. Management aims at correction of lower limb alignment either with physiotherapy, use of insoles or surgical correction and muscle strengthening with specific exercise programs.

Osgood-Schlatter disease is a traction apophysitis of the anterior tibial tuberosity and a common cause of anterior knee pain in athletic children. Treatment includes activity modification, physiotherapy, ice and occasionally NSAIDs.

Patellar tendinopathy is characterized by inflammation and degenerative changes of the patellar tendon and is a common cause of anterior knee pain, specially in athletes of jumping sports. Nonoperative treatment starts with relative rest, ice, NSAIDs and physiotherapy. Several injections are also available, such as PRP or hidrodissection. Surgery is the final option.

This syndrome is one of the most common causes of anterior knee pain in adolescents and young adults, usually being aggravated by knee flexion during weight-bearing activities (as descending stairs or squatting) but also by prolonged sitting. Patellofemoral syndrome results from a functional malalignment, which can be caused by multiple biomechanical imbalances of the lower limb. That being said, the treatment must be towards achieving the correction of the lower limb and trunk alignment as a whole, mainly by stretching and strengthening the appropriate muscles.

Knee collateral ligament sprains are common injuries in sports, being medial collateral sprains more frequent and lateral ones generally associated with other knee injuries. Mechanism of injury is usually a direct force that pushes the knee sideways, and patients describe pain on the injured aspect of the knee and a feeling of instability. Depending on severity of the lesion, treatment varies from relative rest plus ice plus physiotherapy, to adding the use of a knee orthosis, or to having to be operated to repair or reconstruct the injured ligament.

Meniscal tear is a common injury in athletes who suffered a knee trauma but is also frequent in older people as a degenerative lesion. Symptoms can range from a little discomfort to frank pain, catching or locking of the knee and a sensation of instability. Depending on several factors, may be best treated with conservative measures as relative rest, ice, NSAIDs and physiotherapy, occasionally intra-articular injections, or ultimately surgery to repair the meniscus or to remove a part or the whole injured structure.

Pes anserine bursitis refers to an inflammation of the bursa and nearby tendons of the goosefoot, located in the medial and inferior aspect of the knee. The main symptom is pain, which can be aggravated by exercise and climbing stairs but may also be present at rest, specially at night. Treatment may start with relative rest, ice, NSAIDs and should always include a good program of muscle strengthening and stretching exercises. Physiotherapy or local injections may be helpful and finally, if nothing works, surgery to remove the bursa is considered.

Iliotibial band tendonitis is considered an overuse injury associated with repetitive loading of this tendon, specially in running sports’ athletes. The main symptom is pain in the lateral aspect of the knee, which is aggravated by running. There can be a snapping sensation near the area of tendon insertion. In the case of a running athlete, training or shoe modification should be considered. Other than that, relative rest, applying ice, NSAIDs and occasionally a steroid injection may be suitable. Physiotherapy is an essential part of the treatment and in case nothing works surgery can be considered.

Baker’s cyst is a fluid-filled cyst localized in the popliteal fossa at the back of the knee. Usually, it results from a problem inside the knee joint, most commonly knee osteoarthritis. Common symptoms are pain behind the knee, along with difficulty in flexion movement of the knee. It can also be present without causing any symptoms in which case it should not be addressed. Treatment includes relative rest, ice, NSAIDs, physiotherapy, aspiration, and steroid injection of the cyst (usually with ultrasound guidance) and occasionally surgery.

Knee Osteoarthritis is the most common cause of knee pain in older adults and is characterized by degenerative changes of the joint, coupled with occasional inflammatory phases. Usually, pain has a gradual onset and worsens during physical activity but can also be present at rest and be associated with swelling of the knee, along with crepitus sensation and stiffness. Conservative approach includes lifestyle changes, like weight loss, avoiding high-impact activities, physiotherapy, and medication. Several intra-articular injections are available, and, in the end, surgical treatment may be recommended.