What actually happens during a hip arthroscopy

Most patients arrive on the day of their procedure and leave a few hours after it finishes — hip arthroscopy is routinely performed as a day-case in UK hospitals, with no overnight stay required in straightforward cases.

In the anaesthetic room, a general anaesthetic is given so the hip joint can be fully relaxed. Once asleep, the patient is positioned on a traction table, which gently pulls the leg to separate the ball-and-socket surfaces by roughly 1 cm — just enough room to pass instruments safely inside the joint without placing undue stress on surrounding tissue.

The surgeon then makes two to four small incisions, each around 5–10 mm. Sterile fluid is introduced to expand the joint cavity and provide a clear view, and a fibre-optic arthroscope — a slim instrument with a miniature camera and light source — is guided through one of these openings. Live images feed directly to a monitor in the operating theatre, allowing the surgeon to inspect the articular cartilage of the acetabulum and femoral head, the labrum, and surrounding soft-tissue structures in real time.

If damage is identified — frayed or thinning cartilage, a torn labrum, loose bony fragments — specialised micro-instruments can be passed through the remaining incisions to address it straight away. Assessment and treatment therefore happen within the same operative session, removing any need for a return to theatre. The whole procedure typically takes 60–90 minutes.

Why imaging alone often misses hip cartilage damage

MR arthrography — an MRI scan performed after contrast dye is injected directly into the hip joint — is the standard imaging step before hip arthroscopy and provides genuinely useful structural context: the overall shape of the joint, broad labral anatomy, and gross cartilage contours. What it cannot reliably do is confirm whether cartilage damage is present or absent in the zones that matter most clinically.

A 2025 study using arthroscopy as the reference standard found that even high-resolution, deep-learning-enhanced MRI achieved only 37–42% overall sensitivity for detecting cartilage lesions — meaning roughly six in every ten damaged areas went undetected on the scan. The shortfall was most acute in the posteroinferior acetabular and posterior femoral zones, where sensitivity fell below 6%. These are precisely the load-bearing regions where cartilage deterioration carries the greatest clinical significance and where early characterisation of a lesion is most likely to influence what happens next.

Arthroscopy closes this gap not by interpreting reflected signals but by placing a camera inside the joint itself. The surgeon views the cartilage surface directly, grades lesion depth and area in real time, and can act on what is found within the same session. This is why arthroscopy is formally the gold standard for cartilage assessment — the benchmark against which imaging results are measured — rather than simply an extension of the pre-operative workup.

What arthroscopy can find inside the hip joint

Inside the joint, the surgeon works through a systematic assessment covering several distinct structures — and the findings from each can alter the direction of treatment.

Cartilage grading

Articular cartilage on both the acetabular socket and femoral head is graded using the Outerbridge scale, which runs from 1 to 4 and reflects how deeply damage penetrates:

• Grade 1 — surface softening or swelling with the cartilage skin still intact, comparable to paint that has dulled without yet flaking
• Grade 2 — partial-depth fissuring involving less than 50% of cartilage thickness
• Grade 3 — damage extending beyond 50% of cartilage depth, with significant surface disruption
• Grade 4 — full-thickness loss, exposing the underlying bone

Alongside depth, the surface area of any defect is recorded. Both pieces of information feed directly into the decision about whether cartilage preservation, repair, or eventual joint replacement is the most appropriate next step.

Other structures assessed

The labrum, the joint capsule, and the overall bony shape of the socket and femoral head are inspected in the same session. At the anterosuperior head–neck junction — where CAM deformities typically arise — a colour-based boundary between capsule fibrocartilage and hyaline articular cartilage provides a reliable intraoperative landmark for any bone reshaping required; undercorrection of a CAM lesion at this point is a recognised cause of ongoing symptoms after surgery.

Conditions routinely identified include femoroacetabular impingement syndrome (FAIS), labral tears, acetabular dysplasia, synovitis, loose bodies, and ligament damage. Taken together, the assessment yields a detailed diagnostic map of the joint interior — structural information that shapes every subsequent decision on the care pathway.

Why the grade found at arthroscopy shapes long-term decisions

The grade recorded at arthroscopy is not simply a descriptor for the operative note — it carries measurable weight across the years that follow.

Long-term outcome data make this concrete. A study with minimum 10-year follow-up found that patients who required reoperation after primary hip arthroscopy for FAIS had high-grade acetabular chondral defects in 33% of cases, compared with 8% in those who did not require further surgery (p=0.004). That fourfold difference underlines how strongly intraoperative cartilage findings predict the durability of the initial procedure.

Grade 4, full-thickness loss, carries particular significance in younger patients. In a cohort with a mean age of 31 years, full-thickness chondral injury was associated with meaningfully worse pain scores and patient-reported functional outcomes than partial-thickness or absent damage — a finding that makes early grading especially relevant for active patients who have many decades of hip use ahead of them.

Conversion to total hip replacement is also related to what arthroscopy shows. Acetabular chondral defects graded above Outerbridge 2, combined with a high BMI, are independently associated with progression to arthroplasty — giving cartilage grading a direct influence on surgical planning well beyond the arthroscopy itself.

The Royal Orthopaedic Hospital reports hip arthroscopy achieves meaningful pain improvement in approximately 70–80% of patients. Around 5% experience worsening, most commonly where irreversible arthritis was already established before the procedure. This figure is not a reason to avoid assessment; it is precisely why thorough pre-operative cartilage evaluation matters — identifying joints where arthroscopy cannot halt progression allows the care pathway to be planned honestly from the outset.

What can be treated during the same procedure

The assessment and the first stage of treatment often happen in a single theatre visit, sparing eligible patients a return to hospital before repair work can begin.

Symptomatic interventions

Chondroplasty — arthroscopic debridement of frayed cartilage surfaces — can reduce mechanical irritation and ease symptoms. It is a symptomatic intervention, not a regenerative one; it tidies the joint but does not restore cartilage tissue. Loose body removal and labral repair or debridement are completed in the same session where findings indicate them.

Restorative interventions and their limits

Microfracture can stimulate a biological repair response in smaller focal defects by perforating the subchondral bone to release marrow cells. The limitation is the quality of tissue produced: evidence shows the fibrocartilage repair that results tends to break down within two to three years, and repeated microfracture also damages the subchondral bone plate, which can compromise future repair options. Use has therefore declined. Scaffold-augmented marrow stimulation — AMIC — provides a more durable biological environment and is increasingly preferred where marrow stimulation is being considered.

CAM resection for femoroacetabular impingement is carried out arthroscopically in the same session, guided by the anatomical landmarks assessed during the cartilage inspection.

When a planned second stage follows

If grading reveals a larger or more complex defect — one better suited to a procedure such as MACI, OATS, or a fresh osteochondral allograft — the arthroscopy has still done essential work: it has confirmed defect dimensions and established candidacy for the subsequent repair. A second stage in these circumstances is planned clinical progression, not a failure of the first visit.

Costs and access for hip arthroscopy in Lincolnshire

Private costs for hip arthroscopy follow a consistent pattern across the UK. An initial specialist consultation typically costs £250–£350, and a pre-operative MR arthrogram adds £350–£900. The all-inclusive surgical package — covering hospital fees, surgeon, and anaesthetist — generally falls between £4,000 and £8,000, with base facility-only prices starting at around £2,300 before professional fees. More complex interventions, such as labral repair, can take costs beyond this range.

In Lincolnshire, two private routes are accessible. Circle Health Group's The Lincoln Hospital provides orthopaedic assessments and fixed-price packages; specific hip arthroscopy pricing requires a direct enquiry following consultation. Lincolnshire Hip — with clinics in Grantham and Sleaford — is the region's dedicated hip-specialist provider, focused entirely on hip joint care.

NHS hip arthroscopy is available through standard referral routes. Patients wanting an accurate picture of current waiting times at their local trust are best served by asking their GP directly, as figures vary by site and change frequently. For those who prefer to avoid an uncertain wait, both private options are accessible from most parts of Lincolnshire without travelling to London — and an early specialist assessment can establish whether the procedure is appropriate before any commitment to a pathway is made.

Lincolnshire Hip is part of the MSK Doctors group and accepts patients without a GP referral.

1. [1] Hip arthroscopy. https://en.wikipedia.org/?curid=31963181 https://en.wikipedia.org/?curid=31963181
2. [2] EP93 A Technique for determining the Proximal Margin of CAM Resection in Hip Arthroscopy. (2025). https://doi.org/10.1093/jhps/hnaf069.225 https://doi.org/10.1093/jhps/hnaf069.225
3. [3] Deep learning and conventional hip MRI for the detection of labral and cartilage abnormalities using arthroscopy as standard of reference. (2025). https://doi.org/10.1007/s00330-025-11546-9 https://doi.org/10.1007/s00330-025-11546-9
4. [4] EP245 Hip morphology is related with the severity of cartilage injury under hip arthroscopy in patients younger than 40 years old. (2025). https://doi.org/10.1093/jhps/hnaf069.343 https://doi.org/10.1093/jhps/hnaf069.343