Making Sense of Your Hip Imaging Report
A hip MRI or pelvis X-ray report reads like a foreign language until someone walks you through the acetabular labrum, the femoral head, and the abductor tendons that stabilize the joint. The articles below unpack cam and pincer morphology, alpha angle and centre-edge angle measurements, Tonnis grading, and the rehabilitation milestones that follow arthroscopy or a hip replacement, so you can follow along with your surgeon or radiologist instead of just nodding along.
Will It Heal on Its Own?
Decoding Hip Imaging Reports
Hip Rehab, Phase by Phase
Angles, Grades and Stages
Choosing Between Hip Imaging Options
Reading the Report Section by Section
Most hip MRI reports open with the acetabular labrum, the ring of fibrocartilage that deepens the socket and seals joint fluid in place. Radiologists describe labral tears by clock-face position — anterior-superior tears are the most common pattern in younger, active hips — and by whether the tear is a simple fray or a full-thickness detachment. Right below that, most reports flag femoroacetabular impingement as cam morphology (an extra bump of bone on the femoral neck), pincer morphology (over-coverage from the socket rim), or a mixed pattern combining both.
Two numbers do most of the work in an impingement work-up. The alpha angle measures how round the femoral head-neck junction stays as it rotates inside the socket; a value above roughly 55 degrees flags cam-type bone that can pinch the labrum during deep hip flexion. The lateral centre-edge angle measures how much bony roof covers the femoral head from the side — a low centre-edge angle points toward dysplasia and under-coverage, while a high one supports a pincer-type diagnosis. Read together, these two angles say whether a hip is impinging, under-covered, or somewhere between the two.
Further down, the report turns to the joint space itself. Narrowing is measured in millimetres and staged with the Tonnis grade, which runs from grade 0 (no changes) through grade 3 (bone-on-bone with cyst formation), and it is one of the strongest predictors of how close a hip is to needing a replacement. A separate line usually covers the femoral head, where radiologists look for avascular necrosis — patches of bone that lost their blood supply and show up as a dark band on MRI or a crescent sign on X-ray, both of which change staging and treatment options.
Around the outside of the joint, the gluteus medius and gluteus minimus tendons attach to the greater trochanter and form the hip's abductor system. A report describing tendinosis, partial tearing, or a full-thickness tear here explains lateral hip pain that can be mistaken for arthritis. The trochanteric bursa sits right next to those tendons, and its own inflammation — greater trochanteric pain syndrome — is graded separately from any tendon tear even though the symptoms overlap heavily.
Pelvis imaging almost always includes the sacroiliac joints, where the spine meets the pelvis. Reports note joint space width, subchondral sclerosis, and erosions, which matter for telling mechanical SI joint pain apart from an inflammatory process such as ankylosing spondylitis. Because the SI joints sit at the edge of most hip-focused MRI protocols, a dedicated pelvis view is sometimes ordered separately to get a clearer look.
Labral tears rarely heal by growing new cartilage, but many settle into a stable, low-symptom state once the underlying impingement or instability is addressed. Abductor tendinosis and bursitis usually respond to load management and targeted strengthening, while full-thickness tendon tears and advanced avascular necrosis are far less likely to improve without a procedure. This section walks through what actually changes on repeat imaging for each of these conditions.
Reading a hip MRI or pelvis X-ray report gets easier once you know which structure each paragraph is describing and which measurement drives the recommendation. This set of guides walks through the sequences radiologists use for the labrum, cartilage, and bone marrow, and translates the shorthand that shows up between the findings and the impression.
Rehabilitation after hip arthroscopy or a total hip replacement follows a predictable arc: protecting the repair or implant, restoring hip flexor and abductor strength, then rebuilding the single-leg control needed for walking, stairs, and sport. These guides set out the milestones physiotherapists check for at each phase and the warning signs that mean a phase needs to slow down.
Impingement, dysplasia, and hip arthritis each use their own grading language: alpha angle and centre-edge angle for impingement and dysplasia, the Tonnis grade for arthritis, and Goutallier grading for fatty change in the abductor tendons. These articles explain what each grade or stage means for treatment planning.
X-ray, MRI, MR arthrogram, and CT each answer a different question about the hip: X-ray for alignment and Tonnis staging, MRI for labrum and tendon detail, MR arthrogram for subtle labral tears in younger, active hips, and CT for precise bony morphology before surgical planning. These comparisons explain when a surgeon typically orders each one.
See What Your Hip Imaging Shows
Upload your hip MRI, pelvis X-ray, or CT DICOM files for private, AI-assisted analysis.
Start AnalysisEducation, Not a Diagnosis
Nothing on this site replaces a hip surgeon or a musculoskeletal radiologist. These articles explain the vocabulary and measurements that appear in hip MRI, X-ray, MR arthrogram, and CT reports so you can have a more informed conversation about your own imaging, but only a clinician who has examined your hip and reviewed your full study can turn those findings into a diagnosis or a treatment plan.
Frequently Asked Questions
What does the alpha angle on my hip MRI mean?
The alpha angle measures how round the junction between the femoral head and neck stays as the hip moves through flexion. A value above roughly 55 degrees is usually flagged as cam morphology, meaning extra bone at the neck can pinch the labrum during deep bending. It is one measurement, not a diagnosis on its own, so it is read alongside the labrum findings and your symptoms.
How is hip arthritis graded on an X-ray?
Hip X-rays are commonly staged with the Tonnis grade, running from grade 0 (no visible changes) to grade 3 (bone-on-bone contact with cyst formation and marked joint space loss). The grade helps a surgeon judge how far the joint has progressed and whether conservative care, an osteotomy, or a hip replacement is the more realistic next step.
Will my labral tear heal without surgery?
A torn labrum does not regrow cartilage, but many tears become stable and asymptomatic once the impingement or instability driving them is managed with activity changes and targeted strengthening. Tears with mechanical catching, locking, or ongoing pain despite several months of rehabilitation are more likely to be discussed for arthroscopic repair or debridement.
What is the difference between a hip MRI and an MR arthrogram?
A standard hip MRI images the joint without any injection. An MR arthrogram adds contrast fluid injected directly into the hip capsule before scanning, which outlines the labrum and cartilage surfaces more sharply. Surgeons often request an arthrogram when a standard MRI is inconclusive for a subtle labral tear in a younger, active patient.
How long does recovery after hip arthroscopy take?
Most patients use crutches for one to three weeks, regain full range of motion by six to eight weeks, and return to impact sport between four and six months, though labral repair and microfracture procedures run toward the longer end of that range. Our rehabilitation guides break each stage down into the strength and control targets a physiotherapist checks before progressing.
What should I expect from physiotherapy after a hip replacement?
Early physiotherapy after a hip replacement focuses on safe walking distance, hip precautions, and gentle range of motion, then shifts toward abductor and hip flexor strengthening as the implant settles. Most patients walk without an aid by six weeks and return to low-impact activities such as swimming or cycling within three months, with full strength gains continuing for up to a year.