Patellar Tenderness

For Medical Students

What It Tests

Patellar tenderness is elicited by palpating the patella's borders, its articular facets and the tendon above and below it, and the position of the tenderness separates the diagnoses.

The patella has a front surface that can be tender from a direct blow, borders that can be tender from a traction or dislocation injury, facets that can be tender from articular change, and attachments that can be tender from tendon disease. 2.4.1 covers the anatomy.

The front of the knee is where several diagnoses overlap, so a precise location is worth more here than anywhere else in the palpation. 4.2.8 covers pain location.

How It Is Performed

With the knee extended and the quadriceps relaxed, hold the patella and move it medially and laterally, noting its mobility.

Palpate the medial border by displacing the patella laterally and pressing on the exposed medial facet, and the lateral border by the reverse.

Palpate the superior and inferior poles and the tendon attachments at each. 4.6.6 covers tendon tenderness.

Palpate the front surface directly, which is where a prepatellar bursa or a contusion is tender.

Flex the knee to ninety degrees and palpate the patellar tendon under tension, then extend it again and palpate the tendon relaxed, since tendon tenderness changes with tension.

What a Positive Means

Tenderness on the medial border and medial facet after a dislocation indicates a medial retinacular injury, which is the characteristic finding. 4.2.22 covers the dislocation event.

Tenderness on the lateral facet with a tight lateral structure suggests lateral patellar compression rather than instability. 2.4.4 covers tracking.

Tenderness at the inferior pole suggests patellar tendinopathy at its origin, and it is tender with the tendon relaxed rather than under tension. 4.6.6 covers it.

Tenderness on the front surface with a boggy swelling indicates a prepatellar bursa rather than an intra-articular problem. 4.3.8 covers swelling.

Diffuse facet tenderness with crepitus on movement suggests articular change, and the age and the history carry it. 4.7.6 covers the painful arc.

MRCS Level

How It Is Performed

In a viva this is a station where precision is the whole mark, and naming the specific positions is what demonstrates it.

The expected points are the relaxed quadriceps, patellar mobility, the medial and lateral facets by displacement, the poles, the front surface, and the tendon under tension and relaxed.

Say that you would assess patellar mobility and apprehension in the same examination, since instability and pain often coexist. 4.2.2 covers instability as a symptom.

Say that you would assess the tracking in the sitting position, because tracking is active and the palpation is not. 4.3.4 covers the sitting assessment.

Say that you would look at the rotational alignment, since malrotation is a common underlying cause of anterior knee pain. 4.5.6 covers it.

What a Positive Means

The reasoning expected is that the patella's facets articulate with the trochlea through a range, so facet tenderness localises to the part of the articulation loaded at that angle. 2.4.3 covers patellar biomechanics.

The medial retinaculum tears when the patella dislocates laterally, which is why medial tenderness follows a lateral dislocation and is one of the few palpation findings with a specific mechanism. 2.4.5 covers surgical relevance.

A tendon's tenderness changes with tension because loading the tendon alters the pressure your finger can apply, which is the basis for examining it in two positions. 4.6.6 covers tendon tenderness.

The prepatellar bursa lies outside the joint, which is why a bursal problem leaves the range of movement intact. 4.7.1 covers active motion.

How Good It Is

Patellar palpation is the most precisely localising part of the knee examination, because the structures are superficial and separated by millimetres.

It is specific when the location is precise and non specific when recorded as anterior knee tenderness, which is how it is usually recorded.

Facet tenderness is reproducible and is present in asymptomatic knees, so a positive finding needs a complaint to match it.

It cannot grade articular change, which imaging does, and it cannot separate tendinopathy from a partial tear. 4.1.6 covers that relationship.

No figures appear for any accuracy comparison on this page, under decision 023, and the comparison is the claim being made.

FRCS Level

How Good It Is

At decision level patellar palpation contributes to the patellofemoral decisions and to little else, which is a narrow and genuine contribution.

Medial tenderness after a first dislocation contributes to the decision about whether the retinaculum is repaired, alongside the imaging and the number of episodes. 4.2.22 covers the event.

Inferior pole tenderness with a characteristic history is a tendinopathy diagnosis made clinically, and imaging adds staging rather than diagnosis. 4.6.6 covers it.

Facet tenderness with crepitus and a painful arc in an older patient is articular change, and the treatment is not arthroscopic. 4.7.6 covers the painful arc.

In a knee with anterior pain and a ligament complaint the palpation separates the two, which matters because operating on the ligament leaves the pain. 4.11.6 covers a knee where both coexist.

Where It Misleads

The commonest error is recording anterior knee tenderness, which discards the localisation that is the finding's whole value.

The second is palpating with the quadriceps contracted, which prevents the facets being reached.

The third is reading facet tenderness as a diagnosis in a knee whose complaint is elsewhere.

The fourth is examining the tendon in one position only.

The fifth is attributing anterior pain to the patella without assessing the rotational alignment. 4.5.6 covers it.

Fellowship Level

Where It Misleads

In referred practice patellar palpation is where an anterior problem that has been treated as something else is finally localised.

A patient referred with a meniscal complaint whose tenderness is on the patellar facets and whose pain is on stairs has a patellofemoral problem, and the arthroscopy that was planned would not have helped. 4.2.11 covers aggravating factors.

A patient with a posterior cruciate deficient knee and facet tenderness has patellofemoral loading as a consequence of the deficiency, and treating the patella alone misses the cause. 4.11.6 covers that knee.

A patient with tenderness over a previous tendon harvest site has graft site pain rather than a patellar problem, and the distinction is the position. 4.3.7 covers surgical scars.

In a knee with multiple previous patellofemoral procedures the anatomy is altered and the palpation findings are hard to attribute, which limits what the examination can add. 4.2.30 covers previous surgery.

In medicolegal work medial retinacular tenderness recorded acutely is useful evidence of a dislocation, and it is one of the few patellar findings that carries weight. 4.23.7 covers that setting.