Femoroacetabular impingement (FAI) is a pathologic condition of the hip that leads to osteoarthrosis. The goal of the surgical hip dislocation is to correct the bony malformations to prevent the progression of osteoarthrosis. We investigated the topographical cartilage thickness variation in patients with FAI and early stage osteoarthrosis using an ultrasonic probe during surgical hip dislocation. We performed a prospective case-series of 38 patients (41 hips) that underwent surgical hip dislocation. The mean age at operation was 30.6 (range, 18–48) years. Indication for surgery was symptomatic FAI with 4 hips (10%) with pincer-type, 7 hips (17%) with cam-type, and 20 hips (73%) with mixed-type of FAI. Cartilage thickness was measured intraoperatively using an A-mode 22 MHz ultrasonic probe at 8 locations on the acetabular cartilage. The thickest acetabular cartilage was found in the weight bearing zone (range 2.8–3.5mm), whereas the thinnest cartilage was in the posterior acetabular horn (1.0–2.2 mm). In all hips, cartilage was thicker in the periphery area compared to the central area. In the anterior and posterior acetabular horn, the anterior area, and the superior area (central parts) a significantly decreased cartilage thickness in pincer-type compared to cam-type of FAI was found (p<0.05). Cartilage thickness shows topographical differences in all types of FAI with pincer-type of FAI having generally thinner cartilage than cam-type FAI. This is the first study measuring in vivo cartilage thickness in the human hip

Cam type femoroacetabular impingement (FAI) is due to an aspheric femoral head, which is best quantified by the alpha angle described on MRI and CT-scan. Radiographic measurement of the alpha angle is not well codified and studies from the literature cannot conclude on the best view to measure it. Most authors also describe a mixed type FAI which associates an aspheric femoral head with an excessive anterior acetabular coverage of the femoral head. Anterior center edge (ACE) angle has been described on the false profile view to measure anterior acetabular coverage in hip dysplasia and has never been evaluated in FAI. In this study, we developed a new lateral hip view which associates a lateral view of the femoral neck and a false profile view of the acétabulum, which we called profile view in impingement position (PVIP). Twenty six patients operated for FAI had CT-scan, the PVIP and the false profile view of one or two hips according to pain. A control group of 19 patients who did not suffer from the hip had the PVIP. Alpha angles were measured twice on 17 CT scan of FAI patients by two observers and compared with the alpha angles measured on the corresponding hip PVIP by a correlation analysis. Alpha angles were measured twice on 45 PVIP in FAI patient and on 19 PVIP in the control group by three observers. ACE angles were measured once on 15 PVIP and on 15 false profile views. Means were compared by two tail paired t-tests, intra- and inter-observer reliability were measured by intraclass correlation coefficient. Mean alpha angle on CT scan was 65.8° and 65.6° for observers 1 and 2 respectively (p>0.05). It was 63.6° and 64.3° on the PVIP (p>0.05). No significant difference was found between CT scan and radiographic measurements, and Pearson's correlation coefficients were good at 0.74 and 0.8. ICC was 0.86 for inter-rater reliability, and 0.91 for intra-rater reliability for CT-scan alpha angle measures. ICC for PVIP measures varied from 0.82 to 0.9 for intra-rater reliability and from 0.6 to 0.9 for inter-rater reliability. Mean alpha angle measured on PVIP in FAI patients was 63.3° and was 44.9° in control subjects and the difference was significant (p<0.001) for the three observers. None of the FAI patients and 88% of the control subjects had an alpha angle < 50°. Mean ACE angle was 26.8° on PVIP and 32.8° on the false profile view, the difference was significant (p=0.015), and the Pearson's correlation coefficient was moderate (r=0.58). The PVIP is a reliable radiographic view to measure the alpha angle. It allows a good quantification of the alpha angle comparable to CT-scan measurements and permits to differentiate patients from control subjects. PVIP is not a good view to quantify anterior edge angle probably because of acetabular retroversion due to the hip flexion needed in this view. Mean ACE angle measured on the false profile view in FAI patient was comparable to ACE angle in general population reported in the literature

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples. Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34). Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples. We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement

Introduction. Femoroacetabular impingement (FAI) is a relatively recent recognised condition and a potential cause of anterior hip pain in the young military adult population. Both Cam and Pincer type FAI may lead to inflammation, labral tears, and or damage to the smooth articular cartilage of the acetabulum leading potentially to early osteoarthritis of the hip. Open Surgical hip dislocation using the Ganz Trochanteric Flip approach is an accepted technique allowing osteoplasty of the femoral neck and acetabular rim combined with labral repair if required. We present our results of this technique used in military personnel. Methods. All Military personnel who underwent FAI surgery in our unit since August 2006 were included in the study. Functional outcome was measured using the Oxford hip and McCarthy non-arthritic hip scores pre and post-operatively. Results: 13 hips in 11 patients with an average age of 36 years (21–45) underwent surgical hip dislocation for treatment of FAI. Average time of downgrading prior to surgery was 9.3(3-18) months. 6 out of the 11 patients have been upgraded to P2. Average time to upgrading was 6.8(3-17) months. There were no infections, dislocations, or neurovascular complications. Mean Oxford Hip Score improved from 22.8(range 8–38) to 39.5(11–48) and mean McCarthy hip score from 49.6(33.75–80) to 79.2(36.25–100) with an average follow up of 19.4 months (range 4– 42 months). Discussion. The early results of surgical hip dislocation in military personnel are encouraging. Long-term follow-up is required to see if this technique prevents the natural progression to osteoarthritis

Background. Femoroacetabular impingement (FAI) may be a predisposing factor in progression of osteoarthritis. The use of hip arthroscopy is in its infancy with very few studies currently reported. Early reports show favourable results for treatment of young patients with FAI. This prospective study over a larger age spectrum represents a significant addition to this expanding field of minimally invasive surgery. Methods. Over a twenty-two month period all patients undergoing interventional hip arthroscopy were recorded on a prospective database. Patient demographics, diagnosis, operative intervention and complications were noted. Patients were scored pre-operatively and postoperatively at 6 months and 1 year using the McCarthy score. Results. 94 patients met the criteria for inclusion in this study. Median age was 39 (15–66) years with 57.4% female, 16 patients were over the age of 50 years. At operation, 50 patients had a labral tear, 70 had cam impingement and 62 had chondral damage, with 21 of these deemed severe (grade 3 or 4). For all patients a mean increase in the McCarthy score of 14.6 (p=<0.0001) was seen at 6 months and 19.1 (p=0.0002) at 1 year postoperatively. For those over 50 years, at 6 months an increase of 11.9 (p=0.08) was seen, improving to 33.8 (p=<0.0001) at 1 year. Eight patients underwent THR, of these, 2 were over 50 years of age. All of this group of patients had chondral damage (50% judged as severe at arthroscopy). At 6 months postoperatively these patients had severe pain and their mean score worsened by −16.3 (p=0.2). Few complications were seen, 7 patients had tight access (5 males), 3 of which received chondral scuffing and 1 had the procedure abandoned, 1 patient had groin labral bruising and 2 patients had transient parasthesia. Conclusions. Patients see a gradual and significant improvement post hip arthroscopy, with symptoms continuing to improve until 1 year. This is a well-tolerated procedure with a low complication rate and the opportunity for treatment of a range of hip pathology. Patients over the age of 50 gain a significant improvement from this procedure. Two groups of patients who gain no improvement are those with inflammatory arthropathy and those with dysplastic acetabulae

Aims

Malreduction of the syndesmosis has been reported in up to 52% of patients after fixation of ankle fractures. Multiple radiological parameters are used to define malreduction; there has been limited investigation of the accuracy of these measurements in differentiating malreduction from inherent anatomical asymmetry. The purpose of this study was to identify the prevalence of positive malreduction standards within the syndesmosis of native, uninjured ankles.

Purpose. The purpose of this retrospective study was to investigate the acetabular morphology of pincer impingement hips in order to better understand damage pattern in these patients. We compared MRI measurements made at different postions from anterior to posterior on the acetbulum in patients with pure pincer type FAI to those made in patients with pure cam-type to collect parameters that may be useful in the diagnosis and classification of pincer impingement. Material and Methods. From an initial consecutive retrospective population of 1022 patients that underwent MRI with clinical impingement signs 78 hips which were selected with as clear cam (n=57) or pincer (n=21) impingement on plain radiographics. On these MR Imaging was performed with a 1.5-Tesla system. For analysis, a lateral angle of overcoverage on coronal MRI (MR_LCE), the MR extrusion index and the alpha angle (after Nötzli) were used. In addition to these the gamma angle, the acetabular depth and the angle of lateral acetabular overcoverage were described clock-wise on 7 radial slides from anterior to posterior. These were compared between the cam and pincer population using students-t-test. Measurements were obtained by two observers and inter-observer variability was assessed. Results. The acetabular depth showed in all 7 positions significant smaller values for pincer-type in comparison to cam-type impingement. Highest difference was found is superior-posterior position. The acetabular angle is also significant smaller for pincer than for cam in all radial positions. Highest difference of the acetabular angle is located in superior (pincer −102.93°/cam 109.62°) and anterior-superior position (pincer 102.48°/cam 108.77 °). The gamma angle showed significant differences in all radial positions except anterior position. The highest difference is located in superior-posterior position (pincer 86.18 °/cam 08.77°). The mean MR extrusion index was significant lower for pincer type (12.73%) compared to cam-type patients (17.76%) (p=0.004). LCE angle and extrusion index on MRI displayed a Person correlation coefficient of 0.920. The correlation of the acetabular depth and angle was 0.638. Conclusion. There are several morphological differences between pincer and cam acetabuli: They are significantly deeper in all radial positions than cam hips. They tend to have greater retroversion and have smaller gamma angles. Our results suggest that the superior-posterior quadrant displays greater coverage in pincer hips than cam hips, and therefore damage to the labrum and cartilage surface may extend further into the posterior portion of the acetabulum in pincer hips than in cam hips

Introduction. Ectopic ossification (EO) at the acetabular rim has been suggested to be associated with pincer impingement and to lead to ossification of the labrum. However, this has never been substantiated with histological, radiographic and MRI findings in large cohorts of patients. We hypothesized that it is more a bone apposition of the acetabular rim and that it occurs more frequently in coxa profunda (CP) hips. Materials and Methods. In the first part, a cohort of 20 hips with this suspected ectopic rim ossification (EO) pattern were identified. The radiographic features that could be associated with this ossification pattern were described and evaluated by a histologic examination of intra-operative samples taken from the rim trimming. In the second part, we assessed the prevalence of this ectopic ossification process in a cohort of 203 patients treated for FAI. Results. Histologic examination revealed that new acetabular bone formation was either overgrowing the non-ossified labrum or moving it away from the native rim. Radiologically, this was associated with an “indentation sign” and/or a “double line sign”. There were no specimens that had shown any evidence of labral ossification. EO was found in 26 hips (18%) of the second cohort. Twenty of 26 hips (77%) with EO had CP morphology and 29% of CP hips had EO signs. In contrast, only 6 non-profunda hips (8%) were associated with EO. There was a high correlation between XR and MRI findings as >80% of XR findings were confirmed on MRI. Sixty-nine hips had CP morphology. The double line sign (N = 13), the indentation sign (N = 12) and a prominent lateral rim (N = 11) were found. Hips with an EO pattern were found in patients that were significantly older than those without EO (p = 0.01). The acetabular characteristics of the EO groups were not significantly different from the CP hips without EO. The femoral characteristics were significantly different between groups with lower neck shaft angles (128° vs 134°;p = 0,0002) and shorter femoral necks lengths (62mm vs 65mm; p = 0,04)) in the EO group. The mean Tonnis classification was not significantly different (p = 0,18). In addition, the mean acetabular cartilage degeneration status was not different between both groups (p = 0,9). Rim trimming down to the native acetabular bone was done in all cases either by arthroscopy (N = 40) or open surgical dislocation (N = 17). Discussion. Ectopic ossification of the acetabular rim predominantly occurs in CP and is associated with specific anatomic features of the proximal femur. This type of impingement seems to be different and less aggressive than other described impingement processes. The double line sign and indentation sign are highly indicative for this EO process and are indicative for a longstanding impingement problem. Trimming of the acetabular rim should be conducted