Why chondral damage makes FAI a different condition

Being told you have FAI and cartilage damage in the same breath is significant — not because one is simply a worse version of the other, but because cartilage involvement shifts the condition into a clinically different category with a different prognosis and a different treatment pathway.

FAI arises when the bones forming the hip joint are not quite the right shape. In cam impingement, the femoral head (the ball) is not fully round; it has an extra bony prominence that grinds against the socket lining — the acetabular cartilage — with every flexion and rotation. This grinding action is the most directly cartilage-destructive pattern in FAI, concentrating shear force at the junction where cartilage meets the labral rim. In pincer impingement, the acetabulum (the socket) overhangs too far, crushing the labrum under the bony rim rather than shearing cartilage outright — but the transmitted force still causes a contrecoup chondral injury on the femoral head opposite the impact point.

Over years, each cycle of abnormal contact adds micro-damage. When that accumulation crosses a threshold into macroscopic cartilage loss — visible thinning, fissuring, or full-thickness defects — the joint is no longer dealing with a friction problem alone. It is dealing with a structural deficit that neither rest nor physiotherapy can reverse, and that conservative management addresses only partially.

Symptoms that suggest cartilage is now involved

For most people with uncomplicated FAI, the pain is activity-related — groin discomfort that flares during sport, prolonged sitting, or hip flexion, then settles with rest. Range of motion feels tight, but structured physiotherapy and activity modification often make a meaningful difference over weeks.

The picture tends to shift when cartilage damage becomes significant. Pain stops tracking activity as predictably: it may be present at rest or overnight, and it returns earlier during exercise and lingers longer afterwards. Mechanical symptoms — a catching sensation deep in the groin, an audible click, or a fleeting sense of giving way — may begin to intrude. These suggest disrupted or displaced cartilage rather than simple bone-on-bone friction, though catching and clicking alone are not specific enough to confirm the degree of damage; in context, they are a signal worth taking seriously, not a verdict.

The most telling sign, in practice, is a reduced or stalling response to rehabilitation that was previously helping. If a structured physiotherapy programme has plateaued or symptoms have worsened despite good adherence over several weeks, it is worth returning to a specialist for reassessment — because persisting with the same approach when cartilage loss is the dominant pathology is unlikely to change the trajectory.

How chondral damage in FAI is assessed and graded

Establishing how much cartilage damage is present — and how severe — usually takes more than one type of scan, because each modality answers a different question.

Weight-bearing X-rays are taken first: they reveal the bony architecture of the hip, confirm cam or pincer morphology, and show whether joint space has narrowed — the earliest plain-film indicator of cartilage loss. MRI, ideally performed as an MR arthrogram (with gadolinium injected into the joint), adds detail that plain film cannot: it characterises labral tears, maps cartilage signal changes, and gives a sense of lesion extent. CT is reserved mainly for cases where detailed three-dimensional bone anatomy is needed ahead of surgical planning.

A clinically important limitation applies to MRI: it systematically underestimates both the size and depth of cartilage defects when the findings are later compared directly at arthroscopy. In practical terms, a scan result describing 'mild' or 'superficial' cartilage damage may not reflect the full picture inside the joint. Patients and clinicians should hold imaging findings with some caution — they guide, rather than settle, the assessment.

Lesion severity is formally graded using the ICRS or Outerbridge classification. Partial-thickness damage (Grades 1 and 2) generally carries a more favourable outlook and a wider range of treatment options. Once a defect reaches full-thickness cartilage loss — through to the underlying bone (Grades 3 and 4) — the window for joint-preserving treatment narrows substantially. When clinical suspicion of deep damage remains high but imaging is equivocal, diagnostic arthroscopy may be the only reliable way to establish the true grade.

Starting with conservative care

Knowing that cartilage is involved does not automatically mean surgery comes next. The standard starting point is a structured, supervised conservative programme — and a meaningful proportion of patients manage their symptoms effectively within it without progressing further.

Hip-specific physiotherapy drives this phase: targeting range of motion, hip stabiliser strength, and the movement patterns that concentrate load on the damaged area. Activity modification and load management run alongside, reducing the repetitive stress that would otherwise accelerate wear.

Intra-articular injections — corticosteroid or hyaluronic acid — are sometimes added when pain is limiting participation in rehabilitation. They can offer meaningful symptomatic relief, but neither modifies the cartilage itself. Their role is to create a window in which physiotherapy can progress, not to arrest the underlying damage.

Three to six months is the standard timeframe for a structured conservative trial. This is not a waiting period — it reflects the time genuinely needed to distinguish a real treatment response from short-term fluctuation. If symptoms worsen steadily, or catching and giving-way sensations become more prominent during an adequate trial, that pattern is a clear signal to re-evaluate the approach rather than continue unchanged.

Escalation: what treatment looks like when conservative care is not enough

Grade 3 or 4 lesions confirmed on imaging or at arthroscopy — or a clinical course that has worsened steadily through an adequate conservative trial — shift the decision toward active treatment.

For focal defects where surrounding cartilage is intact and joint space is preserved, an injectable collagen scaffold — such as ChondroFiller, delivered as an ultrasound-guided outpatient procedure — offers a regenerative option before surgery is needed. These acellular matrix devices create a structural environment that recruits the patient's own progenitor cells to lay down new cartilage; they are suited to partial- or focal full-thickness lesions with clear, healthy borders.

Where surgery is the appropriate route, the choice turns on defect size and the underlying bony anatomy. Hip arthroscopy offers an important advantage here: the surgeon can correct the original cam or pincer deformity — removing the source of abnormal contact — while treating the chondral lesion in the same procedure. For focal defects up to roughly 2–4 cm², both microfracture (marrow stimulation to encourage fibrocartilage fill) and mosaicplasty (osteochondral autograft transfer) are established options. For defects of 3 cm² or larger, matrix-induced autologous chondrocyte implantation (MACI) has shown better pain and function outcomes at medium-term follow-up; most of this evidence, however, derives from knee studies — hip-specific randomised data remain limited.

When cartilage loss has become diffuse — no intact borders remaining to contain a focal repair — joint-preserving surgery is no longer viable. This is the point at which arthroplasty enters the conversation. It represents a genuine ceiling, not an arbitrary one, which is why accurate grading and timely specialist assessment matter: the window for tissue-preserving treatment is real and does not stay open indefinitely.

Getting the right assessment in London

Three questions are worth bringing to any specialist assessment: how extensive is the cartilage damage, which stage of the management pathway applies, and whether a tissue-preserving option remains viable at current lesion grade. These reframe the consultation from confirming a diagnosis already established to understanding where on the clinical clock the joint sits — and what that means for the decision ahead.

For London patients, the London Cartilage Clinic on Harley Street provides clinical review alongside access to the ChondroFiller injection — the ultrasound-guided injectable collagen scaffold pathway — for suitable candidates ahead of any surgical consideration. Professor Paul Y. F. Lee leads this service as the UK's certified delivery centre for the treatment.

Book an assessment at londoncartilage.com.

1. [1] Femoroacetabular Impingement. https://en.wikipedia.org/?curid=20754811 https://en.wikipedia.org/?curid=20754811
2. [2] Hip Arthroscopy. https://en.wikipedia.org/?curid=31963181 https://en.wikipedia.org/?curid=31963181