Introduction

The knee being one of the major weight bearing joint in our body, absorbs a lot of stress over the years. Years of stresses across the joint can lead to overuse and malalignment in the structures of the knee joint. This further leads to strain, irritation and inflammation of the quadriceps tendon and can sometimes even lead to tears in the tendon. This may manifest as nagging pain above the knee which maybe associated with swelling and weakness in the functioning of the quadriceps. Quadriceps tendonitis is essentially an overuse injury and sports which are the usual culprits are running, football and volleyball.

 Relevant Anatomy

The quadriceps mechanism involves the confluence of the large quadriceps muscle into a tendon. The patella is cushioned inside the tendon, and this tendon further extends inferiorly from the patella and goes and inserts into the tibial tubercle on the tibia. The tendon along with the patella essentially comprise the quadriceps mechanism. Though functionally the  tendon is treated as one, it comprises of two different structures, the quadriceps tendon inserting on the upper half of the patella and the patellar tendon which is the continuity of the tendon from the lower end of the patella inserting onto the tibial tubercle.

Contraction of the quadriceps brings about straightening of the knee. The patella acts as a fulcrum whereas the femur(thigh bone) and (leg bone)tibia act as levers subjecting the knee joint and surrounding structures to massive loads. The joint reaction forces  are two to three times body weight during walking and upto five times while running.

Causes

An overuse injury, the cause for Quadriceps tendonitis might be intrinsic or extrinsic.

Extrinsic- These factors which include improper footwear, errors in training protocols and very importantly regular playing and  training on hard unforgiving surfaces like cement. Generally excessive training(duration and intensity) and rapid escalation in level of training can be major risk factors for developing quadriceps tendonitis.

Intrinsic-   These are host specific factors and include age, flexibility, and joint laxity Some of the specific host characteristics which predispose an individual are

• Malalignment of the foot, ankle, and leg .
• Flat foot(pes plants),
• Patellar maltracking
• Rotation of tibia
• Leg length discrepancy
• Obesity

Pathology

The strength of the quadriceps tendon  is directly proportional the size, number and orientation of the constituent collagen fibres. A mismatch between the load on the quadriceps and it’s ability to satisfactorily distribute the force can lead to Overuse. This mismatch or overuse can weaken the tendon over time and make it ripe for an impending injury. Repeated microtrauma at the muscle tendon junction can prevent full healing. Tissue breakdown can lead to inflammation and tendonitis ensues(can also cause partial tears). Chronic tendonitis eventually leads to a condition called Tendinosis.

Symptoms

Patients typically localise the pain to the bottom of the thigh, just above the knee cap. Movements of the knee joint can aggravate the pain in this area of tendon attachment.

Sometimes the presentation might include a swelling in the distal thigh, Swelling might be very tender to touch in some cases. Stiffness is usually described in the mornings just after waking up(following a period of relative immobilisation) or after excercise.

Diagnosis

Clinical examination is carried out after through history taking. Tenderness can be usually elicited with palpation of the quadriceps tendon insertion. The knee is examined for range of movement, detecting laxity and structural integrity in various planes.The clinician should rule out intrinsic and extrinsic factors affecting the knee eg.sudden changes in training habits.  Alignment of the knee, foot and ankle is checked. In case of a ruptured quadriceps tendon, a gap might be palpated at the insertion site. Weakness in the extensor mechanism might be indicative of insufficiency of the quadriceps.

An X-ray  of the knee can show fractures or the presence of calcium deposits in the quadriceps muscle but these do  not pick up soft tissue injuries. High definition Ultrasound and MRI are the preferred investigations in diagnosing tears, tendonitis and tendinosis. Ultrasound can be further helpful in guiding Regenerative treatments like Platelet Rich Plasma and Prolotherapy.

Treatment

CONSERVATIVE TREATMENT

The initial treatment  initiated usually involves rest, ice , elevation and anti inflammatory medication. The offending activity(eg running) must be stopped.

Relative rest to gradually increasing activities promoting recovery is the way to go. However if the patient experiences pain at rest, Immobilisation with a splint or brace is initially undertaken. Relative rest is a term used to describe a process of rest-to-recovery based on the severity of symptoms. Pain at rest means strict rest and a short time of immobilization in a splint or brace is required. When pain is no longer present at rest, then a gradual increase in activity is allowed so long as the resting pain doesn’t come back.

Physical therapy plays an extremely crucial role in rehabilitation. Modalities like ice massage, local ultrasound  application and electrical stimulation help in limiting the pain and inflammation. Stretching and strengthening exercises serve the purpose of correcting muscle imbalances. Eccentric Muscle strengthening helps in patients where the contributing factor is constant eccentric muscle loading in closed chain kinetic activities.( Closed chain- foot is in contact with the ground)

Heat may be used in cases of chronic tendinosis as it helps in  boosting blood circulation and promotes tissue healing.

Bracing and taping of the patella makes excercises less painful.

INTERVENTIONAL PAIN MANAGEMENT & REGENERATIVE MEDICINE -Platelet Rich Plasma with Prolotherapy- In our experience, we have seen the best results in patients who undergo Prp with prolotherapy,follow a structured excercise regime and are ready to incorporate lifestyle and nutritional modifications to improve the environment of the affected tendon to heal. Image guidance in the form of a high definition ultrasound is used. Prp is delivered at the site of maximum pathology and the rest of the structures are treated with dextrose prolotherapy.

Sometimes, local steroid injection to reduce the inflammation must be undertaken. Care must be taken to avoid successive steroid injections as they can weaken the muscle.

SURGICAL INTERVENTION

If nonsurgical treatment fails to serve the purpose,, surgery may be suggested. Surgery is aimed at  stimulating healing through revascularization (restoration of blood supply).  Damaged tissue is removed and the tendon is repaired.  A  well-planned rehabilitation program lets most patients return to their previous level of activity without recurring symptoms.