Symptoms And Treatment of Knee Pain :

Anterior knee pain is the most common presenting symptoms in many physiotherapy and sports physician practises.1 It contributes substantially to the 20-40% of family practise consultations that relate to the musculoskeletal system. Two common causes of anterior knee pain in sports people are patellofemoral pain and patellar tendinopathy.

We first outline a practical approach to assessing the  patient  with  anterior knee pain particularly with a view to distinguishing the common conditions; we  then detail their management. These concludes with an outline of other cause of anterior knee pain such as fat pad impingement, which may mimic features of both patellofemoral pain and patellar tendinopathy.

Clinical approach

Distinguishing between patellofemoral pain and patellar tendinopathy as a cause of anterior knee pain can be difficult as their clinical features can be similar. Furthermore, on occasions, the two conditions may both be present.

History

There are a number of important factors to elicit from the history of a sportsperson with the general presentation of anterior knee pain. These include the specific location of the pain, the nature of aggravating activities, the history of the onset and behaviour of the pain and any associated clicking, giving way of swelling.

Although it may be difficult for the patient with anterior knee pain to be specific, the area of pain often gives an important clue as to which structure is contributing to the pain .For example, retropatellar or peripatellar pain suggests that the patellofemoral joint (PFJ) is a likely culprit, lateral pain localized to the lateral femoral epicondyle indicates iliotibial band friction syndrome and inferior patellar pain implicates the patellar tendon or infrapatellar fat pad. The patient presents with bilateral knee pain is more likely to have patellofermoral pain or tendinopathy than an interal derangement of both knees.

The onset of typical patellofemoral pain is often insidious but it may present secondary to an acute traumatic episode (e.g. falling on the knee) or post other knee injury (e.g. meniscal, ligament) or knee surgery. The patient presents with a diffuse ache, which is usually exacerbated by loaded activities, such as stair ambulation or running. Sometimes patellofemoral pain is aggravated by prolonged sitting (movie-goers knee), but sitting tends to aggravate pain of patellar tendinopathy so is not diagnostic of patellofemoral pain. Pain during running that gradually worsens is more likely to be of patellofemoral origin, whereas pain that occurs at the start of activity, settles after warm-up and returns after activity is more likely to be patellar tendinopathy. To clinical differentiation of patellofemoral pain, patellar tendinopathy and fat pad impingement. As these conditions can coexist, accurate diagnosis can be challenging.

A history of recurrent crepitus may suggest patellofemoral pain. A feeling that the patella moves laterally at certain times suggests recurrent patellofemoral instability. An imminent feeling of giving way may be associated with patellar subluxation, patellofemoral pain or meniscal abnormality, although frank, dramatic giving way is usually associated with anterior cruciate ligament instability. Nevertheless, giving way due to muscle inhibition, or due to pain, is not uncommon in anterior knee pain presentations.

Examination

Initially, the primary aim of the clinical assessment to determine the most likely cause of the patient’s since location of tenderness and aggravating factors are integral to the differential diagnosis, it is critical to reproduce the patient’s anterior knee pain. This is usually done with either a double- or single-leg squat. A squat done on a decline may make the test more specific to the anterior knee. The clinician should palpate the anterior knee carefully to determine the site of maximal tenderness.

Examination includes:

1. Observation

• standing
• walking
• supine

2. Functional tests

• squats
• step-up/step-down
• jump
• lunge
• double-then single – leg decline squat

3. Paplation

• patella and inferior pole
• medial lateral retinaculum
• patellar tendon
• infrapatellar fat pad
• tibial tubercle
• effusion

4. PFI assessment

static assessment of patella position

• superior
• inferior
• medial
• lateral glide
• dynamic assessment of patella position
• assessment of vasti function

5. Flexibility

• lateral soft tissue structures
• quadriceps
• hamstring
• iliotibial band
• gastrocnemius

Investigations

Imaging may be used to confirm a clinical impression obtained from the history and examination. Structural imaging includes conventional radiography, ultrasound, CT and MRI. Occasionally, radionuclide bone scan is indicated to evaluate the metabolic status of the knee (e.g. after trauma, in suspected stress fracture).

The majority of patients with patellofemoral pain syndrome will require either no imaging, or plain radiography consisting of a standard AP view, a true lateral view with the knee in 300 of flexion, and an axial view through the knee in 300 of flexion. Plain radiography can detect bipartite patella and osteoarthritis, provide evidence of an increased likelihood of Sinding-Larsen-Johansson lesions as well as rule out potentially serious complications such as tumor or infection .Although CT and three dimensional CT have been used to assess the PFI ,MRI is gaining increasing popularity as an investigations of patellofermoral pain, and the unstable patella because of its capacity to image the patellar articular cartilage.

Treatment

Treatment of patellar tendinopathy requires patience and a multifaceted approach, which is outlined. It is essential that the practitioner and patience recognize that tendinopathy that has been present for months may require a considerable period of treatment associated with rehabilitation before symptoms disappear. Conservative management of patellar tendinopathy requires appropriate strengthening exercises, load reduction, correcting biomechanical errors, and soft tissue therapy. An innovation has been the use of sclerotherapy of neovessels with polidocanol.

Surgery is indicated after a considered and lengthy conservative program has failed. This section outlines the physical therapy approach of correction of biomechanics that might be contributing to excessive load on the tendon, targeted exercise therapy and soft tissue treatment before outhning medical treatments including medication, sclerotherapy and surgery.