DOI 10.1002/acr.20055 Acetabular labral tear: do not miss the underlying deformity. Comment on the article by Haroon et al To the Editors: We read with interest the case report by Haroon et al (1) in a recent issue of Arthritis Care & Research. The authors describe a 26-year-old male construction worker who had groin pain for 2 years and was referred to the Spondylitis Clinic for further evaluation. They report that the radio- graphic findings were normal and that magnetic resonance imaging (MRI) showed mild synovitis. The patient’s de- tailed history revealed a mechanical type of pain, and clinical examination showed restriction of internal rota- tion of the hip. MR arthrography showed a tear of the anterosuperior labrum and small marginal osteophytes arising from the femoral head (1). We believe that an important diagnosis was missed in this patient and disagree that the radiograph shown in Figure 1 of the case report is normal. The femoral head is deformed (with a nonspherical extension of the femoral head), there is a decreased anterior head–neck offset, and, as later confirmed by MR arthrography, there is an osteo- phyte at the femoral head visible in the plain radiograph. Therefore, we believe that the patient described above is experiencing a cam-type femeroacetabular impingement (2). Cam impingement usually occurs in young men who are physically active, and these patients are often seen by orthopedic surgeons because of groin pain of unknown origin (2). Internal rotation is typically found to be dimin- ished (3). The radiographic appearance of the deformity has different names, such as pistol grip deformity, tilt deformity, or cam-type deformity. It has been associated with an increased risk of hip osteoarthritis (OA) in the elderly (4) and was proposed to cause early OA in the nondysplastic hip (5). Cartilage and labral damage are explained by the increased radius of the femoral head entering the acetabulum, resulting in shearing forces against the acetabular cartilage, especially during flexion and internal rotation. High-velocity movements, fre- quently occurring during athletic exercises or heavy labor, may play a detrimental role. These lead to an outside-in abrasion of the anterosuperior acetabular cartilage, and to an avulsion of the cartilage at the labrum and the subchon- dral bone at the anterior superior rim (6). Cam impingement is not uncommon and should be rec- ognized not only by orthopedic surgeons but also by rheu- matologists. If conservative treatment fails and a surgical treatment is chosen, the prognosis depends not only on the presence of early OA, but also on the correction of the underlying deformity; if this is missed, resection of the labral tear will probably not yield the expected results (7–11). Stephan Reichenbach, MD, MSc Peter Ju ¨ ni, MD Reinhold Ganz, MD University of Bern Bern, Switzerland Michael Leunig, MD Schulthess Clinic Zurich, Switzerland 1. Haroon N, O’Shea D, Salonen D, Inman RD. Acetabular labral tear mimicking seronegative arthritis in a young male. Arthri- tis Rheum 2009;61:850 –2. 2. Ito K, Minka MA II, Leunig M, Werlen S, Ganz R. Femoro- acetabular impingement and the cam-effect: a MRI-based quantitative anatomical study of the femoral head-neck offset. J Bone Joint Surg Br 2001;83:171– 6. 3. Wyss TF, Clark JM, Weishaupt D, Notzli HP. Correlation be- tween internal rotation and bony anatomy in the hip. Clin Orthop Relat Res 2007;460:152– 8. 4. Doherty M, Courtney P, Doherty S, Jenkins W, Maciewicz RA, Muir K, et al. Nonspherical femoral head shape (pistol grip deformity), neck shaft angle, and risk of hip osteoarthritis: a case– control study. Arthritis Rheum 2008;58:3172– 82. 5. Ganz R, Parvizi J, Beck M, Leunig M, Notzli H, Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res 2003;417:112–20. 6. Beck M, Kalhor M, Leunig M, Ganz R. Hip morphology influ- ences the pattern of damage to the acetabular cartilage: femoro- acetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br 2005;87:1012– 8. 7. May O, Matar WY, Beaule PE. Treatment of failed arthro- scopic acetabular labral debridement by femoral chondro- osteoplasty: a case series of five patients. J Bone Joint Surg Br 2007;89:595– 8. 8. Philippon MJ, Schenker ML, Briggs KK, Kuppersmith DA, Maxwell RB, Stubbs AJ. Revision hip arthroscopy. Am J Sports Med 2007;35:1918 –21. 9. Kim KC, Hwang DS, Lee CH, Kwon ST. Influence of femoro- acetabular impingement on results of hip arthroscopy in pa- tients with early osteoarthritis. Clin Orthop Relat Res 2007; 456:128 –32. 10. Larson CM, Guanche CA, Kelly BT, Clohisy JC, Ranawat AS. Advanced techniques in hip arthroscopy. Instr Course Lect 2009;58:423–36. 11. Bardakos NV, Vasconcelos JC, Villar RN. Early outcome of hip arthroscopy for femoroacetabular impingement: the role of femoral osteoplasty in symptomatic improvement. J Bone Joint Surg Br 2008;90:1570 –5. DOI 10.1002/acr.20060 Reply To the Editors: We thank Dr. Reichenbach and colleagues for their in- terest in our case report. The main purpose of our report was to caution rheumatologists against always attributing hip pain to arthritis. Our patient had an acetabular labral tear with which he presented to our clinic, and this had Arthritis Care & Research Vol. 62, No. 5, May 2010, pp 743–746 © 2010, American College of Rheumatology LETTERS 743