Ganz et al. propose femoroacetabular impingement as the primary mechanical cause of early osteoarthritis in most nondysplastic hips. The paper defines cam and pincer impingement types based on in-situ inspection during more than 600 surgical hip dislocations. It describes each type's distinct damage pattern, demographics, and surgical correction via the trochanteric flip dislocation approach.
Before this paper, osteoarthritis in young patients with radiographically normal hips was labeled idiopathic, and labral tears found at arthroscopy were treated as primary pathology rather than as signs of an underlying mechanical problem.
When you see a young man with groin pain, limited internal rotation, and a positive impingement test, think cam FAI — not a labral tear in isolation. The chondral lesion is already there, and treating only the labrum without addressing the non-spherical head will fail.
When you see a middle-aged woman with acetabular overcoverage (coxa profunda, retroversion), think pincer FAI. The labrum fails first, but the goal is to restore clearance. Rim resection or reverse PAO. Not just labral debridement.
This paper is the reason every FAI workup now includes assessment of head-neck offset, acetabular version, and coverage on plain films before arthroscopy. It also established that periacetabular osteotomy can create FAI if clearance is not preserved. A principle that applies every time you plan a corrective osteotomy around the hip.
Ganz et al. propose femoroacetabular impingement as the primary mechanical cause of early osteoarthritis in most nondysplastic hips. The paper defines cam and pincer impingement types based on in-situ inspection during more than 600 surgical hip dislocations. It describes each type's distinct damage pattern, demographics, and surgical correction via the trochanteric flip dislocation approach.
Before this paper, osteoarthritis in young patients with radiographically normal hips was labeled idiopathic, and labral tears found at arthroscopy were treated as primary pathology rather than as signs of an underlying mechanical problem.
When you see a young man with groin pain, limited internal rotation, and a positive impingement test, think cam FAI — not a labral tear in isolation. The chondral lesion is already there, and treating only the labrum without addressing the non-spherical head will fail.
When you see a middle-aged woman with acetabular overcoverage (coxa profunda, retroversion), think pincer FAI. The labrum fails first, but the goal is to restore clearance. Rim resection or reverse PAO. Not just labral debridement.
This paper is the reason every FAI workup now includes assessment of head-neck offset, acetabular version, and coverage on plain films before arthroscopy. It also established that periacetabular osteotomy can create FAI if clearance is not preserved. A principle that applies every time you plan a corrective osteotomy around the hip.