Ganz, Clin Orthop Relat Res 2003 - Femoroacetabular Impingement: A Cause for Osteoarthritis of the Hip - Article Summary

Femoroacetabular Impingement: A Cause for Osteoarthritis of the Hip

Ganz, Siebenrock, et al.·Clin Orthop Relat Res·2003·3,410 citations·Case series

Ganz and colleagues proposed that femoroacetabular impingement drives early osteoarthritis in nondysplastic hips, and outlined how to recognize and treat it.

Concept paper drawn from more than 600 surgical hip dislocations, with direct intraoperative inspection of joint damage.

Methods

Design: Concept paper based on operative experience
Patients: More than 600 surgical hip dislocations (case mix not described)
Basis: Damage pattern seen in situ at surgical dislocation
Dynamic confirmation of where the damage arose

Key Points

The authors proposed rim impingement between femur and acetabulum as the mechanism behind early osteoarthritis in most nondysplastic hips.
Their concept puts hip motion, rather than axial load, at the center of joint damage.
Citing their earlier series of 26 reverse periacetabular osteotomies for acetabular retroversion, the authors reported impingement confirmed in all and anterosuperior labral and chondral lesions in over half.
Labral tears without cartilage injury were seen only in early pincer impingement, and the authors considered isolated traumatic labral tears rare.
Surgery aims to give the hip more room to move and to stop the femur abutting on the acetabular rim.
The authors proposed that early surgery may slow degeneration in these young patients, beyond relieving symptoms.

Board pearl

In pincer impingement, chronic leverage of the head against an often anterior rim can cause a contre‑coup cartilage lesion in the posteroinferior acetabulum.

Cam vs pincer impingementGanz, Clin Orthop Relat Res 2003

	Cam	Pincer
Cause	Femoral head of increasing radius jams into the acetabulum in forceful motion, especially flexion	Linear contact of the acetabular rim with the head‑neck junction from acetabular overcoverage
Typical patient	Young athletic men	Middle‑aged women
Damage	Shear abrades anterosuperior rim cartilage from outside in, and the labrum tears secondarily	Labrum fails first. Leverage can injure posteroinferior cartilage (contre‑coup)
Cartilage lesions	Deep, often with extensive labral tears	Limited to a small rim area, more benign

Cause

Cam: Femoral head of increasing radius jams into the acetabulum in forceful motion, especially flexion
Pincer: Linear contact of the acetabular rim with the head‑neck junction from acetabular overcoverage

Typical patient

Cam: Young athletic men
Pincer: Middle‑aged women

Damage

Cam: Shear abrades anterosuperior rim cartilage from outside in, and the labrum tears secondarily
Pincer: Labrum fails first. Leverage can injure posteroinferior cartilage (contre‑coup)

Cartilage lesions

Cam: Deep, often with extensive labral tears
Pincer: Limited to a small rim area, more benign

Authors' conclusion

It is proposed that early surgical intervention for treatment of femoroacetabular impingement, besides providing relief of symptoms, may decelerate the progression of the degenerative process for this group of young patients.