MBA Purpose:To compare the alpha-angle measurements in volunteers and patients with femoroacetabular impingement (FAI) and to develop potential threshold values. Materials and Methods:This study was approved by the institutional review board; all individuals signed informed consent. Magnetic resonance (MR) images at 1.5 T in 106 individuals (ages 20-50 years) were analyzed in 53 patients (33 cam-and 20 mixed-type FAI) and 53 age-and sex-matched asymptomatic volunteers. Alpha angles were measured on radially reformatted MR images of the proximal femur by two independent readers. Intraclass correlation coefficient (ICC) and receiver operating characteristic (ROC) were calculated. Results:Mean alpha angles were highest in the anterosuperior segment: 65.4° 6 11.5 [standard deviation] and 65.2° 6 7.3 for readers 1 and 2 in patients and 53.3° 6 9.6 and 55.0° 6 8.8 in volunteers, respectively (P , .001, patients vs volunteers). Alpha angles greater than 55° were measured in 20 (38%) and 33 (62%) of 53 volunteers for readers 1 and 2, respectively. Maximal alpha angle in any segment was substantially different (P , .001) in patients and volunteers (70.3° 6 11.2 vs 57.9° 6 10.5 for reader 1; 69.4° 6 8.8 vs 58.7° 6 8.9 for reader 2), with a large overlap. Overall interobserver agreement was good (ICC, 0.712). ROC showed the largest area under the curve at the anterosuperior segment: 0.791 and 0.824 for readers 1 and 2, respectively (P , .001). A 55° alpha-angle threshold value gave a sensitivity and specificity of 81% and 65% for reader 1 and of 90% and 47% for reader 2, respectively. A 60° alpha-angle threshold value gave a sensitivity and specificity of 72% and 76% for reader 1 and 80% and 73% for reader 2, respectively. Conclusion:There is substantial overlap in the alpha-angle measurements between volunteers and patients with cam-type deformities. Discrimination is best at the anterosuperior segment. Increasing the alpha-angle threshold value from 55° to 60° reduces false-positive results while maintaining a reasonable sensitivity.q RSNA, 2012 1

Femoral antetorsion can be measured rapidly and with good reproducibility with MR imaging. Patients with pincer-type FAI had a significantly larger femoral antetorsion than patients with cam-type FAI.

Purpose Sulcus-deepening trochleoplasty restores the trochlear groove in patients with patellofemoral instability and underlying trochlear dysplasia. There are types of dysplasia both with (B and D) and without (A and C) a supratrochlear spur. The aim of this study was to identify influencing factors for the clinical outcome following trochleoplasty. Methods Forty-four knees in 38 patients who underwent trochleoplasty for instability (type A in 9, B in 15, C in 9 and D in 11 knees) were assessed clinically with the Kujala score and radiologically with radiographs and MRI. The median follow-up was 4 (2-7.8) years. Results At follow-up, the median Kujala score had improved from 68 (29-84) to 90 (42-100) points (P \ 0.001). Instability (P \ 0.001) and pain (P = 0.027) decreased significantly, but in 3 knees, pain was worse postoperatively. Twenty-seven knees were ranked as excellent, 10 as good, 2 as fair and 5 as poor. Overall, dysplasia types B and D benefited more from surgery than types A and C. The postoperative MRI revealed no chondrolysis or subchondral necrosis, but deterioration of cartilage on the lateral trochlear facet was identified. Conclusion Trochleoplasty is a useful and reliable surgical technique to improve patellofemoral instability in patients with a dysplastic trochlea. While improved stability is predictable, pain is less predictable and may even increase following surgery. The overall results were directly dependent on the type of the dysplasia, with a significantly better clinical outcome in type B and D. The clinical relevance of this study is that severe dysplasia can successfully be treated with trochleoplasty. Level of evidence III.

Patients with a nonoperatively managed, moderately symptomatic massive rotator cuff tear can maintain satisfactory shoulder function for at least four years despite significant progression of degenerative structural joint changes. There is a risk of a reparable tear progressing to an irreparable tear within four years.

No abstract

When compared to SHD, HA results in faster recovery and better short-term outcome. However, some overcorrection of the cam deformity and limited frequency of labrum refixation with HA in this study may have a negative impact on long-term outcome.

Objectives: Imaging assessment for the clinical management of femoroacetabular impingement syndrome (FAIS) remains controversial because of a paucity of evidencebased guidance and notable variability in clinical practice, ultimately requiring expert consensus. The purpose of this agreement is to establish expert-based statements on FAIS imaging, using formal techniques of consensus building driven by relevant literature review. Methods:The validated Delphi method and peer-reviewed literature were used to formally derive consensus among 30 panel members (21 musculoskeletal radiologists and 9 orthopedic surgeons) from 13 countries.Forty-two questions were agreed on, and recent relevant seminal literature was circulated and classified in five major topics ("General issues", "Parameters and reporting", "Radiographic assessment", "MRI evaluation" and "Ultrasound") in order to produce answering statements.The level of evidence was noted for all produced statements and panel members were asked to score their level of agreement with each statement (0 to 10) during iterative rounds. Either "group consensus", "group agreement" or "no agreement" was achieved.Items near consensus were further queried using 4 moderated group sessions and in 4 Delphi rounds.Results: Forty-five statements were generated and group consensus was reached for 43 (95.7%). Seventeen of these statements were selected as most important for dissemination in advance. There was no agreement for the two statements pertaining to "Ultrasound". Conclusion:The first international Delphi-based consensus for the imaging assessment of FAIS was developed. The resulting consensus can serve as a tool to reduce variability in clinical practices and guide further research for the clinical management of FAIS. Key Points• FAI imaging literature is extensive although often of low level of evidence.• Radiographic evaluation with a reproducible technique is the cornerstone of hip imaging assessment.• MRI with a dedicated protocol is the gold standard imaging technique for FAI assessment.

Diagnosis of Propionibacterium acnes bone and joint infection is challenging due to the long cultivation time of up to 14 days. We retrospectively studied whether reducing the cultivation time to 7 days allows accurate diagnosis without losing sensitivity. We identified patients with at least one positive P. acnes sample between 2005 and 2015 and grouped them into "infection" and "no infection." An infection was defined when at least two samples from the same case were positive. Clinical and microbiological data, including time to positivity for different cultivation methods, were recorded. We found 70 cases of proven P. acnes infection with a significant faster median time to positivity of 6 days (range, 2 to 11 days) compared to 9 days in 47 cases with P. acnes identified as a contamination (P < 0.0001). In 15 of 70 (21.4%) patients with an infection, tissue samples were positive after day 7 and in 6 patients (8.6%) after day 10 when a blind subculture of the thioglycolate broth was performed. The highest sensitivity was detected for thioglycolate broth (66.3%) and the best positive predictive values for anaerobic agar plates (96.5%). A prolonged transportation time from the operating theater to the microbiological laboratory did not influence time to positivity of P. acnes growth. By reducing the cultivation time to 7 days, false-negative diagnoses would increase by 21.4%; thus, we recommend that biopsy specimens from bone and joint infections be cultivated to detect P. acnes for 10 days with a blind subculture at the end. P ropionibacterium acnes is a facultative anaerobic Gram-positive rod, abundant on the human skin, and mainly associated with the sebaceous glands of the shoulder and axilla (1). It is most commonly associated with the chronic skin disease acne vulgaris. However, it may also cause bone and joint infections, including implant-associated infections. P. acnes has been recognized as an emerging cause of shoulder infections (2, 3) and is among the most common pathogens isolated in shoulder periprosthetic joint infections (PJI) (4, 5). P. acnes has also been implicated in other biofilm-related infections (6-8), such as cardiovascular implantassociated infections (9), spinal osteomyelitis (10, 11), and endophthalmitis (12, 13).Diagnosis of P. acnes bone and joint infections is challenging since pain is often the only symptom (14, 15). For a long time, P. acnes was underdiagnosed in bone and joint infections due to the short cultivation time routinely used in diagnostic laboratories. In general, biofilm-forming bacteria are known to replicate at a slow rate due to low metabolism (16). Since recent studies recommended a prolonged cultivation time of up to 14 days for bone and joint infections (17, 18), the diagnosis of P. acnes infections has become more frequently documented (19). In view of the high costs of a long incubation period, a recent study suggested that 7 days of incubation should be sufficient for accurately diagnosing orthopedic implant-associated infections (20). In this study, 96.6% ...