The key terms in your MRI report, explained

MRI reports are written for radiologists, not patients — so receiving one covered in unfamiliar terms is a frustrating but entirely normal experience. The glossary below covers the words that appear most often in hip MRI reports relating to femoroacetabular impingement (FAI) and labral pathology.

Labral tear

The acetabular labrum is a fibrocartilaginous ring — roughly triangular in cross-section — that rims the hip socket and acts as a gasket seal around the joint. A labral tear means this ring has a split or partial detachment, most commonly at the point where the labrum meets the articular cartilage (the labral-chondral junction). The report may describe this as a 'signal change at the labral-chondral junction' or simply as an anterior or posterior labral tear.

Cam impingement

The hip is a ball-and-socket joint. In cam impingement, the 'ball' (femoral head) is not perfectly round — it carries a bony prominence, the cam lesion, that catches against the inside of the socket during flexion and internal rotation. On an MRI report this appears as a 'non-spherical femoral head' or an elevated alpha angle. The alpha angle is a measurement of how far the femoral head deviates from a true sphere; an angle above roughly 55° is the widely used clinical benchmark for a significant cam deformity, though exact threshold values are always interpreted alongside symptoms and clinical findings.

Pincer impingement

Here the problem lies in the socket rather than the ball. The acetabular rim extends too far and over-covers the femoral head. The report may describe this as acetabular retroversion or a reduced lateral centre-edge angle — both indicate that the rim protrudes beyond its normal boundary and is capable of crushing the labrum beneath it during movement.

Combined-type FAI

Cam and pincer deformities frequently coexist. Most MRI reports describing FAI refer to this combined type rather than a single pure pattern.

Paralabral cyst

A fluid-filled pocket adjacent to the labrum. It forms when joint fluid tracks through a tear, much like water seeping through a crack in a seal. Its presence is a useful secondary sign on an MRI: it suggests the labral tear is structurally real and active, rather than an incidental finding.

Why the labrum tears — and what FAI has to do with it

Think of the labrum as the rubber seal around a refrigerator door. It maintains the pressurised fluid film inside the hip joint that keeps the cartilage surfaces from grinding against each other. When that seal is intact, the femoral head moves smoothly. When it is torn, the pressurised environment is lost — and the cartilage begins to wear at an accelerated rate.

The connection to FAI explains why the two findings appear together on the same report rather than representing separate problems. Both cam and pincer deformities create repeated, low-grade friction at the point where the labrum is attached. With every hip flexion — cycling, sitting down, a deep squat — there is a small mechanical insult to the labral tissue. Across months or years of normal activity, this cumulative microtrauma eventually causes the labrum to split or partially detach.

This is the reason most patients with a labral tear cannot point to a specific incident that 'caused' it. There was no single injury. The tear is the endpoint of a gradual process, which is also why symptoms often begin subtly — a vague groin ache after sport, a catching sensation when standing from a chair — before becoming persistent.

The clinical significance of the finding goes beyond pain. Once the labral seal is disrupted, joint fluid leaks across the tear, articular cartilage loses part of its protective environment, and the rate of cartilage wear increases. This is why an MRI finding of labral pathology warrants specialist review even when current symptoms are mild: the concern is not only today's discomfort but the longer-term risk of early osteoarthritis if the underlying impingement continues unchecked.

When the MRI finding explains your pain — and when it might not

Receiving a report that describes a labral tear or cam morphology can feel like a definitive answer — but the scan describes anatomy, not causation. Whether that anatomy is actually generating your symptoms is a separate clinical question, and one imaging alone cannot resolve.

Cam morphology, for instance, is present in a sizeable proportion of people who played high-volume sport during their teenage years — football, rugby, ice hockey — without ever causing pain. The elevated alpha angle was there throughout; it simply never became symptomatic. Labral signal changes follow a similar pattern: some drive genuine daily pain, others are incidental findings that have been structurally stable for years.

The features that suggest a labral tear is clinically active tend to be consistent: a deep groin ache that worsens with hip flexion (climbing stairs, sitting in a low chair), a catching or clicking sensation at the front of the hip, discomfort that builds after prolonged sitting and eases briefly on standing, and pain at end-range internal rotation. These are the flags a specialist weighs when deciding whether a scan finding warrants treatment.

That assessment combines the imaging with a structured physical examination — controlled provocation tests that load the labrum in the positions where it is most vulnerable — and a careful symptom history. Together, those three sources tell a clinician what the scan alone cannot: whether the anatomy described in the report is the anatomy behind the pain.

What a specialist assessment adds to the scan

A consultation appointment translates the scan findings into a clinical picture. Two standard provocation manoeuvres sit at the centre of that examination: the FADIR test (flexion, adduction, internal rotation), which reproduces pain by compressing the labrum between the femoral head and the acetabular rim, and the FABER test (flexion, abduction, external rotation), which assesses posterior impingement and hip joint irritability. A positive FADIR alongside matching MRI findings substantially strengthens the case that the anatomy described is genuinely symptomatic.

Beyond these tests, the specialist will measure hip range of motion in multiple planes, assess the strength of the surrounding musculature, and establish which positions or activities trigger symptoms. These are features the scan cannot capture: whether internal rotation is already restricted, whether the gluteal muscles have weakened in response to pain, or whether the discomfort is reproducibly tied to the movements that load the impingement zone.

When the clinical picture remains uncertain after examination — perhaps because pain is diffuse, or because adjacent structures such as the hip flexor tendons or lower back could be contributing — a diagnostic intra-articular injection of local anaesthetic can help resolve the question. Temporary pain relief following the injection confirms the hip joint itself as the primary source; absence of relief redirects attention elsewhere. This is a clarifying step rather than a treatment in its own right.

From here, the specialist grades the overall severity — weighing the structural finding, the symptom burden, and the functional impact together — and maps an appropriate pathway. Patients whose symptoms are mild, improving, and unaccompanied by cartilage damage may be managed conservatively without further imaging or immediate intervention at that stage.

Your treatment options at this stage

For most patients, the pathway begins with physiotherapy — not because surgery is off the table, but because structured muscle-control work resolves or significantly reduces symptoms in a substantial proportion of people with FAI and labral pathology. A programme targeting hip flexor and rotator strength, movement pattern correction, and progressive load management gives the joint its best chance to settle without intervention. Activity modification sits alongside this — reducing provocative flexion loads in the short term or adjusting sport technique — but the aim is returning to normal movement, not avoiding it permanently.

When pain limits engagement with physiotherapy, an intra-articular injection provides a practical bridge. Cortisone reduces joint inflammation reliably; PRP is increasingly used where tissue support rather than symptom suppression alone is the goal. Neither repairs the labrum nor changes the bone morphology described in your report — but a well-timed injection can reduce pain enough to make rehabilitation effective, and that is its specific purpose here.

Arthroscopic surgery enters the conversation when optimised conservative care has not resolved symptoms, or when the cam deformity is significant enough that continued loading will predictably worsen cartilage damage. The decision is clinical, not radiological: the MRI finding in isolation is not an indication for surgery. Factors that genuinely drive the surgical conversation include the degree of cartilage involvement, the patient's activity level and age, and a realistic commitment to post-operative rehabilitation.

When FAI and a labral tear coexist, addressing both the bone shape and the labral tissue in a single arthroscopic procedure is considered to give the best outcomes — avoiding the need for revision if the cam lesion is left untreated at the time of repair.

What hip arthroscopy involves and what recovery looks like

Hip arthroscopy is performed through two or three small portal incisions — typically under a centimetre — with the leg briefly distracted to open the joint space. For cam FAI, the surgeon reshapes the non-spherical femoral head through osteoplasty: trimming the bony prominence back to a round contour so it no longer jams against the cartilage lining during flexion. The labrum is then reattached to the acetabular rim using suture anchors. Where pincer over-coverage is also present, the excess rim is trimmed in the same session; combined-type FAI does not require staging across two procedures.

Recovery follows a structured, progressive pathway. Crutches and protected weight-bearing are standard for approximately two to four weeks, with loading increased as pain and movement allow. Most patients are walking normally and driving within four to six weeks of surgery.

Return to sport is governed by functional criteria rather than a fixed date in the calendar. The relevant thresholds — adequate hip strength symmetry, full comfortable range of motion, and the ability to perform sport-specific loading without compensatory movement patterns — are reached at different points depending on the demands of the activity. High-load activities such as cutting sports and distance running typically take longer to reach safely than swimming or cycling. In clinical practice this process commonly unfolds over three to six months, but readiness is assessed individually at each stage.

The factor that most clearly shapes what surgery can achieve is the condition of the articular cartilage at the time of the operation. Patients with a structurally significant cam deformity and an otherwise healthy joint surface tend to do well; where cartilage damage is already established, the procedure can prevent further mechanical harm but cannot reverse what has already occurred. Understanding the cartilage grading within your MRI report — and having it placed in clinical context — is therefore central to forming a realistic expectation of what arthroscopy is and is not likely to deliver.

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
3. [3] Acetabular labrum tear. https://en.wikipedia.org/?curid=77797474 https://en.wikipedia.org/?curid=77797474
4. [4] Acetabular labrum. https://en.wikipedia.org/?curid=6915197 https://en.wikipedia.org/?curid=6915197