What is the recommended management for mild acetabular overcoverage (pincer-type femoroacetabular impingement) of the right hip?

Management of Mild Acetabular Overcoverage (Pincer-Type FAI)

For mild acetabular overcoverage causing symptomatic pincer-type femoroacetabular impingement, begin with conservative management including NSAIDs and physical therapy; if symptoms persist after 3-6 months, proceed with hip arthroscopy for acetabular rim resection and labral repair (not resection) to preserve joint function and delay osteoarthritis progression. 1, 2

Initial Conservative Approach

• Start with non-steroidal anti-inflammatory medications to manage pain and inflammation as first-line therapy 1
• Consider diagnostic intra-articular anesthetic and steroid injection, which serves both diagnostic (confirming the hip as pain source) and therapeutic purposes 1, 3
• Conservative treatment should be attempted for 3-6 months, though it functions primarily as a temporizing measure rather than addressing the underlying structural abnormality 1, 4

Important caveat: Unlike cam-type FAI where the acetabulum may be shallower than normal, pincer-type impingement involves a deeper acetabulum (96° ± 5° vs 87° ± 4° in normal hips), making these distinct pathoanatomic entities 5. This distinction is critical because excessive acetabular rim resection in a patient misdiagnosed as having pincer impingement could render a normal or shallow acetabulum pathologically unstable.

Surgical Indications and Technique

Proceed to arthroscopic surgery when:

• Conservative management fails after 3-6 months 1
• Clinical and radiographic evidence confirms pincer impingement with minimal to moderate degenerative changes 2
• Patient has persistent groin pain with hip catching or locking 6

Arthroscopic Procedure Details

The surgical approach involves: 2

• Peripheral compartment arthroscopy using proximal anterolateral viewing portal with anterior and anterolateral working portals
• Labral assessment and release from capsular reflection
• Limited bony resection of the acetabular rim using a burr (not excessive resection)
• Labral refixation if tissue quality is sufficient (this is critical—labral repair provides better outcomes than resection) 2
• Central compartment arthroscopy under traction for complete visualization

Critical surgical principle: The labrum should be detached to expose the bony overhang, the rim resected conservatively, then the labrum refixed if healthy 2. Labral preservation through repair rather than resection leads to superior clinical outcomes 2.

Management of Associated Chondral Injury

If chondral damage is identified during arthroscopy: 1, 3

• For small delaminated cartilage lesions <3 cm²: perform debridement followed by microfracture of exposed subchondral bone 1, 3
• For lesions >3 cm²: more complex management required, though evidence for specific techniques remains limited 1, 3
• Microfracture technique involves creating 3-4mm deep holes spaced 3-4mm apart in subchondral bone to promote fibrocartilage formation 6

Postoperative Rehabilitation

Rehabilitation protocol differs based on labral management: 2

• If labral resection performed: Partial weight bearing with pain-controlled progression to full weight bearing over 1-2 weeks
• If labral refixation performed: Protected weight bearing (20 kg maximum) for first 4 weeks to allow healing
• All patients: Continuous passive motion therapy and stationary bicycle for 4 weeks, with early proprioceptive training 2

Contraindications to Arthroscopic Treatment

Do not proceed with arthroscopic rim resection in: 2, 5

• Advanced osteoarthritis of the hip joint
• Generalized overcoverage (coxa profunda) where the entire acetabulum is too deep
• Acetabular retroversion in a dysplastic hip (these patients need the coverage)
• Patients with already shallow acetabula (measure acetabular depth preoperatively to avoid iatrogenic instability) 5

Expected Outcomes and Monitoring

• Arthroscopic treatment provides symptomatic relief and improved hip outcome scores in appropriately selected patients 2, 7
• High rate of return to athletic activity when labral refixation is performed 7
• Long-term monitoring is essential as untreated or inadequately treated pincer impingement may lead to progressive cartilage damage and osteoarthritis 1, 3
• Regular follow-up to assess for symptom recurrence or progression 1

Common pitfall to avoid: Do not perform aggressive acetabular rim resection without first confirming the acetabulum is truly overcovered. Cam-type hips are actually shallower than normal (84° ± 5° vs 87° ± 4°), and mistaking a cam deformity for pincer impingement could lead to iatrogenic instability and early joint failure 5.