RESUMO
Purpose: To determine the prevalence of 4 different types of acetabular rim ossifications, including partial labral ossification or punctate calcification, true os acetabuli, acetabular rim stress fracture, and complete labral ossification, and to determine whether different types of periacetabular ossifications are linked to demographic or radiological factors. Methods: We retrospectively reviewed the medial records of patients presenting for hip-related complaints at 2 sports medicine practices from September 2007 to December 2009. An anteroposterior radiograph of both hips and a lateral radiograph of each hip was obtained for all patients and reviewed for findings of cam and pincer femoroacetabular impingement, degenerative changes (Tönnis grade), and periacetabular calcifications for both hips. These parameters were also evaluated with respect to symptoms, sex, and age. Results: Four hundred ninety-one consecutive patients (982 hips) presented to 2 orthopaedic surgeons at 2 centers for "hip"-related complaints. There were 223 males and 268 females (age 39 ± 14 years). The overall prevalence of periacetabular calcifications in hips was 17.6%, with 56.6% of calcifications in the symptomatic hip and 43.4% in the contralateral hip. Four basic patterns of calcification were identified: punctuate calcifications within the labrum (8.0% hips), large rounded calcifications (os acetabuli) (4.2% hip), large fragments with a vertical line of the superior-lateral acetabular rim, consistent with healed or non-healed stress fracture (2.0% hips), and complete ossification of the labrum (3.4% hips). Overall, male sex (P = .002), increased lateral center-edge angle (P = .046), and higher Tönnis grade (P < .001) statistically predicted the presence of periacetabular ossification. Punctate calcifications were more prevalent in males (P = .002). Higher Tönnis grade (P = .029) and increased alpha angle (P = .046) were more prevalent with os acetabuli. Younger age (P = .001), male sex (P = .048), increased alpha angle (P = .012), and increased lateral center-edge angle (P < .001) were more prevalent in acetabular rim fractures. No factors were statistically significant at predicting the presence of an ossified labrum. Conclusions: Periacetabular calcifications are not uncommon. Four particular patterns of calcification are identified: punctate labral calcifications (8%), larger rounded calcifications (i.e., os acetabuli) (4.2%), acetabular rim stress fractures (2%), and complete ossification of the labrum (3.4%) for a combined prevalence of 17.6% in patients presenting to an orthopaedic surgeon with "hip"-related complaints. Nearly half were in the asymptomatic hip. Male sex had a higher prevalence of periacetabular calcifications. An increased lateral center edge angle and higher Tönnis grade also had a higher prevalence of periacetabular calcifications. Younger male patients are more likely to have acetabular rim stress fractures. Patients with an increased alpha angle have a higher prevalence of os acetabuli and rim stress fractures. Clinical Relevance: This study aims to identify, quantify, and categorize periacetabular calcifications about the hip. Their clinical relationships and relevance have been discussed, but no study has distinctly categorized the various types and their prevalence. This study provides a framework for identification and categorization.
RESUMO
PURPOSE: The first purpose of the study was to evaluate the prevalence of various radiographic parameters and pathomorphologies for patients presenting with the diagnosis of hip pain. The second purpose of this study was to identify those pathomorphologies and radiographic parameters that were predictive of clinically suspected intra-articular and hip joint-related symptoms. METHODS: A total of 998 hips (499 patients, 228 males, 271 females, mean age 38 years) presented to 2 orthopaedic surgeons with the diagnosis of hip pain. Patients were retrospectively identified as intra-articular and hip joint-related symptoms or extra-articular and non-hip joint-related symptoms based on history, examination, injection response, and diagnosis listed on clinical notes. A detailed morphologic evaluation of anteroposterior and 45° modified Dunn lateral radiographs of both hips was performed for all patients. RESULTS: The presence of at least 1 finding consistent with femoroacetabular impingement (FAI) was noted in 96.6% of patients (89.9% of hips) and was bilateral in 83%. The prevalence of dysplasia was 10.6% in patients (6.7% of hips) and was bilateral in 2.8%. Cam-type morphology was more common in males (P < .001). Profunda and protrusio were more common in females (P < .001). Acetabular retroversion was more common in males (P = .02). Fifty-seven percent of hips (564/998) were diagnosed clinically with intra-articular and hip joint related symptoms. Cam-type FAI, mixed-type FAI, increasing alpha angle, and increasing Tönnis grade were independent predictors of clinically suspected intra-articular and hip joint symptoms (P < .001), whereas isolated Pincer-type morphology was not. CONCLUSIONS: FAI is highly prevalent (96.6%) and frequently bilateral (83%) in patients presenting to an orthopaedic clinic with hip pain. Cam-type morphology and acetabular retroversion are more frequent in men, whereas profunda and protrusio are more frequent in women. Cam-type morphology, increasing alpha angle (larger cam morphology), and increasing Tönnis grade were highly predictive of clinically suspected intra-articular symptoms, whereas isolated pincer-type morphology was not. LEVEL OF EVIDENCE: Level III, case-control study.
