Sonography-Based Determination of Hip Joint Anterior Alpha-Angle: A Reliable and Reproducible Method

Purpose Femoroacetabular impingement (FAI) is a known risk factor for hip osteoarthritis. The gold standard for diagnostics is X-ray and MRI. The accuracy of hip joint alpha angle measurements obtained using sonography is equal to measurements in MRI for patients with cam impingement of the hip joint. Materials and Methods Patients with hip pain and MRI and sonography were evaluated between January 2015 and December 2019 in a single center. Musculoskeletal sonography was performed according to the DEGUM guidelines by ultrasound-certified specialists. Measurements were repeated three times by two independent investigators. Results 285 patients were screened, and 110 patients (49 females, 61 males) met the inclusion criteria. The mean age at time of investigation of 54 left and 56 right hip joints was 54.2 years. 1320 measurements were performed. The mean alpha angle was 50.7° in MRI and 50.4° in sonography with a mean difference of 0.28° (p>0.05). Conclusion Determining hip alpha angle using sonography is a safe and reproducible method. No statistically significant differences between results in MRI and sonography could be seen. Although this is a retrospective, single-center study including only Caucasian mid-Europeans and with the known limitations of ultrasound imaging, it nevertheless shows that sonography can be used as a simple, cheap, and fast technique to assess the hip alpha angle without losing diagnostic quality.

Soft Tissue CAM Impingement in Adolescents: MRI reveals impingement lesions underappreciated on x-ray (138)

Objectives: The presence of femoroacetabular impingement (FAI) in adolescents has been established. However, the existence of a non-ossified CAM lesion in adolescent femoracetabular impingement (FAI) is not well described. The purpose of this study is to evaluate the presence of a non-ossified or soft CAM lesion in adolescent patients with FAI. Methods: A review of a prospective cohort of patients with symptomatic FAI in an institutional registry was performed. Subjects were included if they had an MRI and lateral x-ray of the hip (45o Dunn, Cross Table, or frog) at a baseline visit. On MRI, evaluation of the anterolateral femoral head was evaluated using radial, coronal, sagittal, or axial oblique sequences. When a soft CAM lesion was identified (all found between 2-5 o’clock), an alpha angle was performed on MRI and plain radiograph. The cohort of soft CAM lesions was reviewed and differences between radiographic and MRI alpha angles were assessed using a paired T-Test. Results: Thirty-one (9.3%) of 332 hips (mean age 16.4 yrs, range 13.66-19.59 yrs; 83.9% F) were identified with a soft impinging lesion at the femoral head-neck junction on MRI. The most common primary sport was track & field (4), the average duration of symptoms was 92.4 weeks and a majority with insidious onset (77.4%). The average alpha angle on MRI was greater than on x-ray [63.53 ± 7.94o vs 51.25 ± 7.92o; p<.05]. All subjects with soft CAM lesions demonstrated soft tissue consistent with extension of the physis (n=1),thickening of the peri-chondral ring (n=22), or thickening of the periosteum (n=8). Twenty-two of these patients (71%) with soft impingement underwent hip preservation surgery (n=13 labral repairs) with improvements in clinical outcome. Conclusions: In adolescent patients with symptomatic hip impingement, MRI may be useful to identify soft CAM lesions (non-ossified) that are under-represented on x-ray.

SOFT TISSUE CAM IMPINGEMENT IN ADOLESCENTS: MRI REVEALS IMPINGEMENT LESIONS UNDERAPPRECIATED ON X-RAY

Background: The presence of femoroacetabular impingement (FAI) in adolescents has been established. However, the existence of a non-ossified CAM lesion in adolescent femoracetabular impingement (FAI) is not well described. Hypthesis/Purpose: The purpose of this study is to evaluate the presence of a non-ossified or soft CAM lesion in adolescent patients with FAI. Methods: A review of a prospective cohort of patients with symptomatic FAI in an institutional registry was performed. Subjects were included if they had an MRI and lateral x-ray of the hip (45o Dunn, Cross Table, or frog) at a baseline visit. On MRI, evaluation of the anterolateral femoral head was evaluated using radial, coronal, sagittal, or axial oblique sequences. When a soft CAM lesion was identified (all found between 2-5 o’clock), an alpha angle was performed on MRI and plain radiograph. The cohort of soft CAM lesions was reviewed and differences between radiographic and MRI alpha angles were assessed using a paired T-Test. Results: Thirty-one (9.3%) of 332 hips (mean age 16.4 yrs, range 13.66-19.59 yrs; 83.9% F) were identified with a soft impinging lesion at the femoral head-neck junction on MRI. The most common primary sport was track & field (4), the average duration of symptoms was 92.4 weeks and a majority with insidious onset (77.4%). The average alpha angle on MRI was greater than on x-ray [63.53 ± 7.94o vs 51.25 ± 7.92o; p<0.05]. All subjects with soft CAM lesions demonstrated soft tissue consistent with extension of the physis (n=1),thickening of the peri-chondral ring (n=22), or thickening of the periosteum (n=8). Twenty-two of these patients (71%) with soft impingement underwent hip preservation surgery (n=13 labral repairs) with improvements in clinical outcome. Conclusion: In adolescent patients with symptomatic hip impingement, MRI may be useful to identify soft CAM lesions (non-ossified) that are under-represented on x-ray.

What Is the Impact of a CAM Impingement on the Gait Cycle in Patients with Progressive Osteoarthritis of the Hip?

(1) Background: The femoroacetabular impingement (FAI) type cam leads to a conflict between the acetabular rim and a bony thickening of the femoral neck junction. While maximal excursions in flexion, adduction and internal rotation provoke pain, the aim of this study was to analyze if a cam morphology shows an impact on gait pattern. (2) Methods: Fifty-five patients with end-stage hip osteoarthritis performed gait analysis before hip replacement as well as three, six and 12 months postoperatively. Thirty-three (60%) of them presented an FAI type cam. An ANOVA was used to compare the hip angles in sagittal, frontal and transversal planes between patients with a FAI type cam (group “+cam”) and without (group “−cam”). (3) Results: Before surgery the patients of the +cam-group showed a tendency towards a reduced flexion and internal rotation at the heel strike (p > 0.05). Over time, the differences were adjusted by total hip arthroplasty. (4) Conclusions: We did not find any differences in the gait analysis of patients with a FAI type cam compared to patients without.

Epiphyseolysis capitis femoris (ECF)

ZusammenfassungDie Epiphyseolysis capitis femoris (ECF) ist die häufigste Hüftgelenkserkrankung des Jugendlichen bei steigender Tendenz. Grund dafür ist der ebenfalls steigende Body Mass Index in dieser Altersgruppe. Um Komplikationen und Folgeschäden zu minimieren, ist eine frühzeitige Diagnostik und Therapie erforderlich, um ein persistierendes Cam-Impingement mit späterer Arthroseentwicklung zu vermeiden. Es gibt sowohl offene als auch arthroskopische Operationsverfahren um eine Rekonturierung des Schenkelhalses nach Abschluss des physiologischen Remodelings zu erzielen. Zu klären bleibt weiterhin die Frage nach dem optimalen Operationsverfahren mit den bestehen Langzeitergebnissen bei Epiphyseolysis capitis femoris.

Cystoscopy as a tool for hip arthroscopy for treating morbidly obese patients: a case report of treating a Sumo wrestler

Sports medicine surgeons sometimes encounter morbidly obese athletes with femoroacetabular impingement, such as Sumo wrestlers. In such cases, traditional arthroscopic equipment will not reach the joint. This case report describes the use of a cystoscope to perform arthroscopy to treat borderline developmental dysplasia of the hip combined with cam impingement in a morbidly obese athlete. The cystoscope enables hip arthroscopy to be performed when traditional instruments are not of sufficient length to access the hip and/or an extra-long arthroscope is not available. The use of the cystoscope provides a practical, feasible and minimally invasive option to treat non-arthritic intraarticular hip pathology in the morbidly obese or extremely muscular athletes.

Radiographic factors associated with hip osteoarthritis: a systematic review

The purpose of this study was to outline factors that contribute to the appearance of hip osteoarthritis (OA). Secondarily, this study aims to describe radiographic factors that are associated with the progression of OA in the arthritic hip. Pubmed/MEDLINE and Embase were searched in November 2018 for radiographic risk factors for hip OA. All articles were eligible if they (i) were written in the English language and (ii) commented on OA as it relates to radiographic description, appearance or progression of OA. Demographic characteristics of the study cohort, definition of OA, baseline OA and factors for prediction or progression of OA were recorded. Nine articles were included in this review. A total of 3268 patients were analyzed across all studies. The mean age was 60.0 years (range 18–91.5). The most common descriptors for OA were dysplasia and cam impingement. Six of the nine articles found acetabular under-coverage to be associated with developing OA. Four articles found cam morphology to be an associated factor. Finally, four articles commented on the factors associated with the progression to more severe grades of OA, reporting exclusively on acetabular under-coverage, whereas only one reported on cam morphology to be associated. This systematic review found acetabular under-coverage followed by cam morphology to be strongly associated with both the development and progression of hip OA. These findings define patients at risk for developing hip OA and emphasize the importance of early awareness of future joint degeneration.

Predictors of total hip replacement in community based older adults: a cohort study

Background Hip osteoarthritis (OA) commonly affects older adults and leads to high morbidity. There is no preventative treatment available and total hip replacement (THR) is offered for end stage disease. Known predictors of THR include pain and radiographic OA. Hip structure has also been shown to worsen hip OA and predict THR. A better understanding of predictors of THR can aid in triaging patients and researching preventative strategies. The purpose of this study is to describe predictors of THR in community dwelling older adults.Methods At baseline, participants had assessment of radiographicOA and cam impingement (from pelvic radiographs), shape mode scores (from dual energy X-ray absorptiometry (DXA)) and hip bone mineral density (BMD) (from DXA). After 2.6 and 5 years, participants reported hip pain using WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), and had hip structural changes assessed using magnetic resonance imaging (MRI). Risk of THR was analysed using mixed-effect Poisson regression.Results Incidence of THR for OA over 14 years was 5.0% (40 / 802). As expected, WOMAC hip pain and hip radiographic OA both predicted risk of THR. Additionally, shape mode 2 score (decreasing acetabular coverage) (RR 1.57 per SD; 95% CI 1.01-2.46), shape mode 4 score (non-spherical femoral head) (RR 0.65/SD; 95% CI 0.44-0.97), cam impingement (α >60°) (RR 2.66/SD; 95% CI 1.38-5.13), neck of femur BMD (RR 1.85/SD, 95% CI 1.4-2.44) and bone marrow lesions (BMLs) increased risk of THR (RR 5.62/unit; 95% CI 1.1 – 28.81). There was a trend for hip effusions to increase the risk of THR (RR 1.88/SD; 95% CI 0.24 to 14.78).Conclusion In addition to hip pain and radiographic hip OA, measures of hip shape, cam impingement, BMD and BMLs independently predict risk of THR. This supports the role of hip bone geometry and structure in the pathogenesis of end stage hip OA and has identified factors that can be used to improve prediction models for THR.