#condition - Knee

Knee Tendonitis

  • Tendonitis means ‘inflammation of a tendon’
  • This can happen spontaneously or from overuse, eg in runners
  • Inflammation of the tendon at the front of the knee below the kneecap is called ‘patellar tendonitis’
  • Inflammation of the tendons just above the front of the knee is called ‘quadriceps tendonitis’
  • Inflammation of the tissues on the outer side of the knee may be due to ‘iliotibial band friction syndrome’
  • The best investigation is an ultrasound scan and/or an MRI scan
  • Most cases of tendonitis respond well to rest / physiotherapy
  • Some cases end up needing cortisone / steroid injections
  • Occasionally, surgery may be required, with a ‘tendon decompression’

What is tendonitis?

A not uncommon cause of pain around the knee is tendonitis. Tendonitis means ‘inflammation of a tendon’. This may occur after trauma, due to repetitive overuse or it can come on spontaneously.

Examples of some specific common tendinopathies around the knee include:

Typically, pain from tendonitis is localisable to one specific point or area and is a burning pain that is aggravated by exercise.

Tendinosis is the condition where there has been chronic tendonitis or long term wear and tear in a tendon, and the tissue has become thickened, degenerate and scarred. The scarring can form a barrier preventing in-growth of blood vessels. This diminishes the blood supply to the tissue, inhibiting the healing process and exacerbating the tendinosis.

Most cases of tendonitis can be treated well with:

  • Anti-inflammatories
  • Rest
  • Modification of activities
  • Splinting
  • Physiotherapy
  • Steroid injections (for inflammation of the tendon sheath – tenosynovitis – but steroids should NOT be injected directly into tendon tissue itself, as this can cause rupture of the tendon.

For those cases where the symptoms are severe or where previous attempts at conservative management have failed, surgical treatment may become necessary.

The basic principles of surgery for tendonitis are to:

  • Address any underlying causative factors, eg a bony spur that may be rubbing against the tendon
  • Excise any severely degenerate tissue
  • Open up the tendon tissue to encourage healing through in-growth of new blood vessels.

Patellar tendonitis

MRI scan (side-on view) of a knee with patellar tendonitis. The tendon should be dark throughout its length. At the top of the tendon, just below the patella, there is a pale area in the tendon, caused by inflammation and swelling.

MRI scan (side-on view) of a knee with patellar tendonitis. The tendon should be dark throughout its length. At the top of the tendon, just below the patella, there is a pale area in the tendon, caused by inflammation and swelling.

Inflammation of the patellar tendon usually occurs in the proximal (upper) part of the tendon, near its insertion where it attaches to the inferior (lower) pole of the patella (kneecap). It is sometimes referred to a “Jumper’s Knee”. This condition causes pain at the front of the knee, just below the kneecap, which is often worse when the knee is flexed. In particular, it may be painful for the sufferer to kneel, sit for long periods, squat or go up / down stairs.

The diagnosis of patellar tendonitis can normally be made clinically. However, it can sometimes be difficult to differentiate clearly between patellar tendonitis and pain coming from the actual patella itself (eg chondromalacia or osteoarthritis). The diagnosis can normally be confirmed clearly by MRI or ultrasound scanning.

Intra-operative view of a patellar tendon showing patellar tendonitis plus degeneration of the tendon.

Intra-operative view of a patellar tendon showing patellar tendonitis plus degeneration of the tendon.

Persistent symptoms from patellar tendonitis that has failed to respond to other conservative measures may require surgical tendon decompression. This requires a small open surgical procedure whereby an incision is made at the front of the knee and the central inflamed portion of the tendon is excised. At the same time, it is sometimes felt appropriate to perform a knee arthroscopy at the same time as the tendon decompression, if it is deemed necessary to try and exclude other potential active pathology within the knee.

Often, patellar tendonitis occurs secondary to patellar tendon impingement, where a small spur of bone from the inferior (lower) pole of the patella rubs against the back of the patellar tendon when the knee flexes. The diagnosis of patellar impingement can normally be seen at ultrasound scanning or otherwise usually is clear on MRI.

In cases of patellar tendon impingement that require surgery, in addition to the tendon decompression the inferior pole of the patella is explored and the bony spur is excised.

Rehab after surgery for patellar tendonitis does vary according to the severity of the condition and the corresponding magnitude of the procedure performed. However, the standard protocol follows the approximate guidelines of:

  • Day 1 – Week 6: Partial weightbearing with a crutch +/- a knee brace
  • Week 6 – Week 12: Physiotherapy to regain range of motion and muscle strength, but no running, jumping, hopping, squatting or heavy weights.
  • 3 months onwards: Gradual return to full activities and sports under the supervision of an appropriate physiotherapist.

Quadricep tendonitis

This condition is similar to patellar tendonitis (see above), except that it occurs in the distal (lower) part of the quadriceps tendon at the upper part of the front of the knee, at the superior (upper) pole of the patella.

Quadriceps tendonitis can be confirmed by ultrasound scanning, and it normally responds well to conservative treatments, only relatively rarely requiring surgical treatment.

Iliotibial band friction syndrome

This is a condition whereby sufferers feel a burning pain around the lateral (outer) part of the knee, overlying the region of the lateral epicondyle of the femur. Pain may radiate up the lateral side of the thigh. The pain usually only comes on with exercise, typically running, and often only comes on after a set distance or time from onset of exercise. The pain normally eases fairly rapidly with rest, although a persistent aching around the area is common.

Anmation of how ITB Friction Syndrome develops

The condition occurs due to some relatively unusual anatomy in this part of the knee. The iliotibial band is a sheet of fascia running down the lateral side of the thigh. Proximally, at the top of the thigh, there is a muscle – tensor fascia lata – that originates from the pelvis and which passes down, attaching to the top of the fascia lata. The whole structure is referred to as the iliotibial band. The fascia lata passes distally, attaching to the proximal tibia at a region called Gerdy’s Tubercle. At the side of the distal end of the femur, there are prominent lumps of bone on either side of the knee; the medial and lateral epicondyles. These are the points of origin of the medial and lateral collateral ligaments.

With the knee flexed, the iliotibial band (ITB) sits posterior to (behind) the bony prominence of the lateral epicondyle. When the knee is flexed to about 20 or 30 degrees, the ITB lies directly over the lateral epicondyle. When the knee is fully extended, the ITB sits anterior to (in front of) the lateral epicondyle. Between the ITB and the lateral epicondyle there is a thin sack of fluid (a bursa) that helps reduce friction between the fascia and the bone. However, if the epicondyle is particularly prominent, if the ITB is over-tight and if the patient undertakes large amounts of exercise, then the ITB can rub excessively on the epicondyle, leading to inflammation, with associated pain.

CLICK HERE TO SEE AN ANIMATION OF HOW ITB FRICTION SYNDROME DEVELOPS

Treatment of ITB Friction Syndrome is based on conservative measures, including:

  • Rest
  • Avoidance of activities that trigger the symptoms
  • Use of anti-inflammatories
  • Physiotherapy
  • Local steroid (cortisone) injections

In situations where conservative measures fail, then surgical treatment may become necessary. This involves making an incision (normally about 5cm long) longitudinally over the lateral side of the knee and then releasing the distal ITB either through a small posterior snip in the tissue or, where necessary, through a larger release and lengthening procedure as appropriate depending on the severity of the condition.

Rehab after surgical treatment of ITB Friction Syndrome normally follows the basic protocol of:

  • Day 1 – Week 6: Supported weight bearing with a crutch
  • Week 6 – Week 12: Gradual incremental muscle strengthening exercises under supervision of an appropriate physiotherapist
  • 3 months onwards: Gradual return to exercises (including running) plus sport under supervision.