Disorders of acetabular labrum and articular cartilage in hip dysplasia: evaluation using isotropic high-resolutional CT arthrography with sequential radial reformation

Incorporating patient-specific hip orientation from weightbearing computed tomography affects discrete element analysis-computed regional joint contact mechanics in individuals treated with periacetabular osteotomy for hip dysplasia

Computational models of the hip often omit patient-specific functional orientation when placing imaging-derived bony geometry into anatomic landmark-based coordinate systems for application of joint loading schemes. The purpose of this study was to determine if this omission meaningfully alters computed contact mechanics. Discrete element analysis models were created from non-weightbearing (NWB) clinical CT scans of 10 hip dysplasia patients (11 hips) and oriented in the International Society of Biomechanics (ISB) coordinate system (NWB-ISB). Three additional models were generated for each hip by adding patient-specific stance information obtained via weightbearing CT (WBCT) to each ISB-oriented model: (1) patient-specific sagittal tilt added (WBCT-sagittal), (2) coronal and axial rotation from optical motion capture added to (1; WBCT-combo), and (3) WBCT-derived axial, sagittal, and coronal rotation added to (1; WBCT-original). Identical gait cycle loading was applied to all models for a given hip, and computed contact stress and contact area were compared between model initialization techniques. Addition of sagittal tilt did not significantly change whole-joint peak (p = 0.922) or mean (p = 0.871) contact stress or contact area (p = 0.638). Inclusion of motion-captured coronal and axial rotation (WBCT-combo) decreased peak contact stress (p = 0.014) and slightly increased average contact area (p = 0.071) from WBCT-sagittal models. Including all WBCT-derived rotations (WBCT-original) further reduced computed peak contact stress (p = 0.001) and significantly increased contact area (p = 0.001). Variably significant differences (p = 0.001-1.0) in patient-specific acetabular subregion mechanics indicate the importance of functional orientation incorporation for modeling applications in which local contact mechanics are of interest.

ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update

Chronic hip pain is a frequent chief complaint for adult patients who present for evaluation in a variety of clinical practice settings. Following a targeted history and physical examination, imaging plays a vital role in elucidating the etiologies of a patient's symptoms, as a wide spectrum of pathological entities may cause chronic hip pain. Radiography is usually the appropriate initial imaging test following a clinical examination. Depending on the clinical picture, advanced cross-sectional imaging may be subsequently performed for further evaluation. This documents provides best practice for the imaging workup of chronic hip pain in patients presenting with a variety of clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The imaging evaluation of acetabular labral lesions

The acetabular labrum is an important structure that contributes to hip joint stability and function. Diagnosing labral tears involves a comprehensive assessment of clinical symptoms, physical examinations, imaging examinations, and arthroscopic confirmation. As arthroscopy is an invasive surgery, adjuvant imaging of the acetabular labrum is increasingly imperative for orthopedists to diagnose and assess labral lesions prior to hip arthroscopy for surgical management. This article reviews the current imaging strategies for the evaluation of labrum lesions.

Understanding Painful Hip in Young Adults: A Review Article

A wide number of disorders, including pathologies outside the hip, can cause and refer pain to hip. However, determining the cause of a painful hip can be a major challenge to orthopedic surgeons. Failure to diagnose and appropriately investigate pathologies of the hip in adults may result in delayed management and prolonged patient morbidity. A systematic approach to investigating the etiology of hip pain in adults (e.g., history, careful clinical and radiographic examination), will help identify the majority of clinically important pathologies which can cause hip pain. Conservative treatment and selective use of injection therapies has proven quite successful for the treatment of most causes of hip pain.

The role of the labrum in early treatment of unstable developmental dysplasia of the hip

The objective of the paper is to analyse the role of the labrum with particular attention to its morphological changes in unstable dysplastic hips during treatment.

Between January 2013 and December 2015, data were collected on 86 unstable, dysplastic hips, which were divided into type D (n = 13), type III (n = 49) and type IV (n = 24). The labrum was evaluated with ultrasound examination (US) for echogenicity and dimensions with inter-/intra-observer tests comparing the US images at diagnosis and at the end of treatment. Statistical analysis was performed.

At the end of treatment of unstable, dysplastic hips, the labrum was more echogenic with a frequency of 97% and was larger with a frequency of 96%.

The labrum has an active stabilizing role in unstable dysplastic hips and it undergoes a statistically significant increase of echogenicity and dimensions after treatment.

Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180053

Utility of radial reformation of three-dimensional fat-suppressed multi-echo gradient-recalled-echo images for the evaluation of acetabular labral injuries and femoroacetabular impingement

OBJECTIVES

To assess the utility of the radial reformation of three-dimensional fat-suppressed multi-echo gradient-recalled-echo (3D FS me-GRE) for evaluating acetabular labral injuries and femoroacetabular impingement (FAI).

MATERIALS AND METHODS

A total of 25 patients with suspected acetabular labral injuries were examined using 3D FS me-GRE and radial 2D T2*-weighted imaging (T2*WI) on a 3-T magnetic resonance imaging (MRI) scanner. The range of acetabular labral injuries was evaluated by radial reformation through the center of the acetabulum perpendicular to the plane across the entire acetabular rim (type 1 radial reformation) of 3D FS me-GRE and radial 2D T2*WI. To evaluate the FAI morphology, we performed radial reformation perpendicular to the central axis of the femoral head and neck (type 2 radial reformation) of 3D FS me-GRE.

RESULTS

Acetabular labral injuries were identified in 23 patients, and no acetabular labral injury was seen in two patients on type 1 radial reformation of 3D FS me-GRE and radial 2D T2*WI. The diagnostic concordance rate for the range of acetabular labral injuries between the two imaging methods was 76.0%, and there was excellent agreement for the injured angles (r = 0.977, p < 0.001). FAI morphology could be evaluated in all patients (no FAI, n = 8; cam, n = 10; pincer, n = 4; combined cam and pincer, n = 3) using type 2 radial reformation of 3D FS me-GRE.

CONCLUSIONS

Type 1 and type 2 radial reformations of 3D FS me-GRE imaging were useful for evaluating acetabular labral injuries and determining whether patients with acetabular labral injuries have FAI, respectively.

Advanced Imaging in Osteoarthritis

Context:

Radiography is widely accepted as the gold standard for diagnosing osteoarthritis (OA), but it has limitations when assessing early stage OA and monitoring progression. While there are improvements in the treatment of OA, the challenge is early recognition.

Evidence Acquisition:

MEDLINE and PubMed as well as professional orthopaedic and imaging websites were reviewed from 2006 to 2016.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Magnetic resonance imaging (MRI) can provide the most comprehensive assessment of joint injury and OA with the advantages of being noninvasive and multiplanar with excellent soft tissue contrast. However, MRI is expensive, time consuming, and not widely used for monitoring OA clinically. Computed tomography (CT) and CT arthrography (CTA) can also be used to evaluate OA, but these are also invasive and require radiation exposure. Ultrasound is particularly useful for evaluation of synovitis but not for progression of OA.

Conclusion:

MRI, CT, and CTA are available for the diagnosis and monitoring of OA. Improvement in techniques and decrease in cost can allow some of these modalities to be effective methods of detecting early OA.

Management of Hip Pain in Young Adults

The diagnosis and treatment of hip pain in the young adult remains a challenge. Recently, understanding of a few specific hip conditions has improved; most notably femoroacetabular impingement. The differential diagnosis of hip pain has also expanded significantly, offering new challenges and opportunities. Along with the diagnostic dilemma, optimal treatment strategies for many conditions have yet to be proven and are current areas of important inquiry. This article reviews the current research on hip pain in the young adult and presents an overview of diagnostic and management strategies.

Cartilage Status at Time of Arthroscopy Predicts Failure in Patients With Hip Dysplasia

The purpose of our study was to determine whether chondral damage at the time of arthroscopy predicted conversion to THA in patients with dysplasia. We identified 166 patients with dysplasia who underwent hip arthroscopy. Forty-seven went on to receive THA. The articular cartilage of three regions of the acetabulum and femoral head were assessed for signs of chondral damage (absent, mild, or severe]). A stepwise multivariable logistic regression analysis revealed mild damage on the posterior femoral head (P=0.001) and severe damage on the anterior acetabulum (P=0.007) made a significant contribution to the predictor. The presence of mild posterior femoral head chondral changes was indicative of more global cartilage damage in this series of patients. Our findings show that chondral damage on the posterior femoral head and anterior acetabulum is a strong predictor of ultimate conversion to THA in dysplastic patients.

MDCT arthrography of the hip: value of the adaptive statistical iterative reconstruction technique and potential for radiation dose reduction

OBJECTIVE

The purpose of this article is to assess the effect of the adaptive statistical iterative reconstruction (ASIR) technique on image quality in hip MDCT arthrography and to evaluate its potential for reducing radiation dose.

SUBJECTS AND METHODS

Thirty-seven patients examined with hip MDCT arthrography were prospectively randomized into three different protocols: one with a regular dose (volume CT dose index [CTDIvol], 38.4 mGy) and two with a reduced dose (CTDIvol, 24.6 or 15.4 mGy). Images were reconstructed using filtered back projection (FBP) and four increasing percentages of ASIR (30%, 50%, 70%, and 90%). Image noise and contrast-to-noise ratio (CNR) were measured. Two musculoskeletal radiologists independently evaluated several anatomic structures and image quality parameters using a 4-point scale. They also jointly assessed acetabular labrum tears and articular cartilage lesions.

RESULTS

With decreasing radiation dose level, image noise statistically significantly increased (p=0.0009) and CNR statistically significantly decreased (p=0.001). We also found a statistically significant reduction in noise (p=0.0001) and increase in CNR (p≤0.003) with increasing percentage of ASIR; in addition, we noted statistically significant increases in image quality scores for the labrum and cartilage, subchondral bone, overall diagnostic quality (up to 50% ASIR), and subjective noise (p≤0.04), and statistically significant reductions for the trabecular bone and muscles (p≤0.03). Regardless of the radiation dose level, there were no statistically significant differences in the detection and characterization of labral tears (n=24; p=1) and cartilage lesions (n=40; p≥0.89) depending on the ASIR percentage.

CONCLUSION

The use of up to 50% ASIR in hip MDCT arthrography helps to reduce radiation dose by approximately 35-60%, while maintaining diagnostic image quality comparable to that of a regular-dose protocol using FBP.

Evaluation of Labral Pathology and Hip Articular Cartilage in Patients with Femoroacetabular Impingement (FAI): Comparison of Multidetector CT Arthrography and MR Arthrography

Background

To compare the multidetector computed tomography (MDCT) arthrography (CTa) and magnetic resonance (MR) arthrography (MRa) findings with surgical findings in patients with femoroacetabular impingement (FAI) and to evaluate the diagnostic performance of these methods.

Material/Methods

Labral pathology and articular cartilage were prospectively evaluated with MRa and CTa in 14 hips of 14 patients. The findings were evaluated by two musculoskeletal radiologists with 10 and 20 years of experience, respectively. Sensitivity, specificity, accuracy, and positive predictive value were determined using surgical findings as the standard of reference.

Results

While the disagreement between observers was recorded in two cases of labral tearing with MRa, there was a complete consensus with CTa. Disagreement between observers was found in four cases of femoral cartilage loss with both MRa and CTa. Disagreement was also recorded in only one case of acetabular cartilage loss with both methods. The percent sensitivity, specificity, and accuracy for correctly assessing the labral tearing were as follows for MRa/CTa, respectively: 100/100, 50/100, 86/100 (p<0.05). The same values for acetabular cartilage assessment were 89/56, 40/60, 71/71 (p>0.05) and for femoral cartilage assessment were 100/75, 90/70, 86/71 (p>0.05). Inter-observer reliability value showed excellent agreement for labral tearing with CTa (κ=1.0). Inter-observer agreement was substantial to excellent with regard to acetabular cartilage assessment with MRa and CTa (κ=0.76 for MRa and κ=0.86 for CTa)

Conclusions

Inter-observer reliability with CTa is excellent for labral tearing assessment. CTa seems to have an equal sensitivity and a higher specificity than MRa for the detection of labral pathology. MRa is better, but not statistically significantly, in demonstrating acetabular and femoral cartilage pathology.

The role of imaging in early hip OA

Hip osteoarthritis (OA) is characterized by cartilage degradation, subchondral bone sclerosis and osteophyte formation. Nowadays, OA is thought to develop via different etiologies that all lead to a similar form of end stage joint degradation. One of these subtypes is related to an abnormal shaped hip joint, like acetabular dysplasia and a cam deformity. These bony abnormalities are highly predictive for development of hip OA, but they are likely to already be present from childhood. This suggests that these deformations induce OA changes in the hip, well before extensive hip degradation becomes present three to four decades later. Accurate detection and successful characterization of these early OA events might lead to better treatment options for hip OA besides nowadays available invasive joint replacement surgery. However, current diagnostic imaging techniques like radiographs or plain magnetic resonance imaging (MRI), are not sensitive enough to detect these subtle early OA changes. Nor are they able to disentangle intertwined and overlapping cascades from different OA subtypes, and neither can they predict OA progression. New and more sensitive imaging techniques might enable us to detect first OA changes on a cellular level, providing us with new opportunities for early intervention. In this respect, shape analysis using radiography, MRI, computed tomography (CT), single photon emission computed tomography (SPECT)/CT, and positron emission tomography (PET) might prove promising techniques and be more suited to detect early pathological changes in the hip joint. A broad application of these techniques might give us more understanding what can be considered physiological adaptation of the hip, or when early OA really starts. With a more clear definition of early OA, more homogenous patient populations can be selected and help with the development of new disease modifying OA interventions.

Computed tomography arthrography with traction in the human hip for three-dimensional reconstruction of cartilage and the acetabular labrum

AIM

To develop and demonstrate the efficacy of a computed tomography arthrography (CTA) protocol for the hip that enables accurate three-dimensional reconstructions of cartilage and excellent visualization of the acetabular labrum.

MATERIALS AND METHODS

Ninety-three subjects were imaged (104 scans); 68 subjects with abnormal anatomy, 11 patients after periacetabular osteotomy surgery, and 25 subjects with normal anatomy. Fifteen to 25 ml of contrast agent diluted with lidocaine was injected using a lateral oblique approach. A Hare traction splint applied traction during CT. The association between traction force and intra-articular joint space was assessed qualitatively under fluoroscopy. Cartilage geometry was reconstructed from the CTA images for 30 subjects; the maximum joint space under traction was measured.

RESULTS

Using the Hare traction splint, the intra-articular space and boundaries of cartilage could be clearly delineated throughout the joint; the acetabular labrum was also visible. Dysplastic hips required less traction (∼5 kg) than normal and retroverted hips required (>10 kg) to separate the cartilage. An increase in traction force produced a corresponding widening of the intra-articular joint space. Under traction, the maximum width of the intra-articular joint space during CT ranged from 0.98-6.7 mm (2.46 ± 1.16 mm).

CONCLUSIONS

When applied to subjects with normal and abnormal hip anatomy, the CTA protocol presented yields clear delineation of the cartilage and the acetabular labrum. Use of a Hare traction splint provides a simple, cost-effective method to widen the intra-articular joint space during CT, and provides flexibility to vary the traction as required.

Correlation of Structural Bony Abnormalities and Mechanical Symptoms of Hip Joints

PURPOSE

The purpose of this study is to determine structural bony abnormalities predisposing for femoroacetabular impingement by comparison of patients with and without mechanical symptoms.

MATERIALS AND METHODS

We conducted this comparative study on 151 patients (151 hips; mean age 44.8 years; range 16-73 years) with mechanical symptoms with results of multi-detector computed tomography (MDCT) arthrography (the symptomatic group). Each patient was matched with a control who underwent MDCT due to ureter stone (the asymptomatic group) in terms of age, gender, site (right or left), and time at diagnosis. Acetabular evaluations, which included cranial and central anteversion and anterior and lateral center edge angles and femoral measurements, were performed. In addition, we evaluated the prevalence and characteristics of structural bone abnormalities between the two groups.

RESULTS

The prevalence for patients who had at least one structural bony abnormality in the symptomatic and asymptomatic groups was 80.1% (121/151) and 54.3% (82/151), respectively (odds ratio: 3.39, 95% confidence interval: 2.30-5.66; P<0.001). The most common osseous abnormality was the isolated Pincer type in both groups: 89 (73.6%) of 121 hips with an osseous abnormality in the symptomatic group and 57 (69.5%) of 82 hips with an osseous abnormality in the asymptomatic group. By analysis of CT arthrography in symptomatic patients, a labral tear was found in 107 hips (70.9%), and 86 (80%) of these hips had a structural bony abnormality.

CONCLUSION

A significantly greater prevalence rate of structural bony abnormality was observed for the symptomatic group than for the asymptomatic group. These findings are helpful for development of appropriate treatment plans.

Visualization of joint and bone using dual-energy CT arthrography with contrast subtraction: in vitro feasibility study using porcine joints

OBJECTIVE

To assess the feasibility of subtracting various concentrations of iodinated contrast material on dual-energy computed tomographic (DECT) arthrography to provide both CT arthrography and virtual unenhanced CT (VUCT) in a single CT acquisition.

MATERIALS AND METHODS

This was an in vitro study for which institutional review board approval was not required. CT arthrographies of 12 joints of pig cadavers were obtained using dual-energy CT. Various concentrations of iodinated contrast material, 25% (75 mg/ml), 50% (150 mg/ml), 75% (225 mg/ml), and 100% (300 mg/ml) were used for the DECT arthrography. The paired regions of interest (ROI) were drawn over the same location on two paired CT scans at different tube voltages (80 kVp and 140 kVp). The average Hounsfield units (HU) ratio of the contrast media(HU on CT at 80 kVp/HU on CT at 140 kVp) was calculated for each joint. Subtraction of contrast material was carried out using VUCT application

RESULTS

The 25% iodinated contrast mixture was successfully subtracted from DECT arthrography of four joints, in which the average HU ratio ranged from 1.95 to 2.0. The subtraction of the 50%,75%, and 100% iodine contrast mixtures was not successful, because of the upper demonstrable HU limit in dual-energy CT.

CONCLUSIONS

DECT arthrography with 25% iodinated contrast medium injection can provide both CT arthrography and virtual unenhanced images in a single CT acquisition.

Diagnostic value of ultrasound and computed tomographic arthrography in diagnosing anterosuperior acetabular labral tears

PURPOSE

This study investigated the sensitivity, specificity, and accuracy of ultrasound as well as the computed tomography arthrography (CTA) findings and arthroscopic findings for the diagnosis of anterosuperior acetabular tear and correlated tear types using the Lage classification system on ultrasound and CTA compared with the arthroscopic findings.

METHODS

We retrospectively reviewed the results of ultrasonographic examinations conducted before injection and after injection of contrast for subsequent CTA in 36 hips (34 patients; 24 men [71%] and 10 women [29%]; mean age, 36 years). All patients had chronic groin pain and a positive impingement test. We analyzed the sensitivity, specificity, and accuracy before injection, after injection, and at CTA and compared these with findings with the arthroscopic findings. Interobserver agreement and intraobserver reproducibility of the presence of a tear and tear type in the anterosuperior quadrant of the acetabular labrum on ultrasonography and CTA were calculated by use of κ coefficients.

RESULTS

The sensitivity, specificity, and accuracy for sonographic detection of labral tear before injection/after injection were 58%/79%, 67%/58%, and 61%/72%, respectively, for observer 1 and 75%/92%, 25%/42%, and 58%/75%, respectively, for observer 2. The sensitivity, specificity, and accuracy for CTA detection of labral tears were 96%, 92%, and 94%, respectively, for observer 1 and 88%, 92%, and 89%, respectively, for observer 2. When the sonographic classification was compared with the arthroscopic findings of observer 1 and observer 2, the accuracy before injection/after injection was only 53%/67% and 58%/75%, respectively. The accuracy of morphologic classification of CTA and arthroscopic findings of observer 1 and observer 2 was 83% and 75%, respectively. Interobserver correlation before injection and at CTA was poor (κ = 0.056) and moderate (κ = 0.642), respectively.

CONCLUSIONS

Although intra-articular injection during sonographic examination could improve diagnosis of labral tears, sonographic examination as a diagnostic technique is still of limited use. However, CTA shows reliable validity in the diagnosis of acetabular labral tears.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Differences in the locations and modes of labral tearing between dysplastic hips and those with femoroacetabular impingement

We investigated differences in the location and mode of labral tears between dysplastic hips and hips with femoroacetabular impingement (FAI). We also investigated the relationship between labral tear and adjacent cartilage damage. We retrospectively studied 72 symptomatic hips (in 68 patients: 19 men and 49 women) with radiological evidence of dysplasia or FAI on high-resolution CT arthrography. The incidence and location of labral tears and modes of tear associated with the base of the labrum (Mode 1) or body of the labrum (Mode 2) were compared among FAI, mildly dysplastic and severely dysplastic hips. The locations predominantly involved with labral tears were different in FAI and mild dysplastic hips (anterior and anterosuperior zones) and in severely dysplastic hips (anterosuperior and superior zones) around the acetabulum. Significant differences were observed in the prevalence of Mode 1 versus Mode 2 tears in FAI hips (72% (n = 13) vs 28% (n = 5)) and severe dysplastic hips (25% (n = 2) vs 75% (n = 6)). The frequency of cartilage damage adjacent to Mode 1 tears was significantly higher (42% (n = 14)) than that adjacent to Mode 2 tears (14% (n = 3)).

Hip pathology is significantly related to the locations and modes of labral tears. Mode 1 tears may be a risk factor for the development of adjacent acetabular cartilage damage.

Cite this article: Bone Joint J 2013;95-B:1320–5.

Effect of pelvic inclination and torsional deformity on canine acetabular morphology with computed tomography. A phantom study

OBJECTIVES

To evaluate how the inclination and torsional deformity of the hemipelvis using extra-rotation as a model affect acetabular angle (AA) and dorsal acetabular rim angle (DARA) assessment with computed tomography (CT).

METHODS

A normal canine hemipelvis positioned in dorsal recumbency was scanned with a 16-slice multidetector CT scanner, with different degrees of torsional deformity, using extra-rotation around the long axis (0-5-10-15°) of the hemipelvis. Each degree of extra-rotation was acquired at 0°, +20° and -20° of gantry tilt, to mimic different pelvic inclinations on its transverse axis. Cranial and central individual acetabular angles (IAA) and central DARA were calculated and correlated with inclination and torsional deformity.

RESULTS

A very strong negative correlation was found between cranial and central IAA, pelvic inclination, and torsional deformity. A very strong positive correlation was found between DARA, pelvic inclination, and torsional deformity.

CLINICAL SIGNIFICANCE

Pelvic inclination and torsional deformity affect acetabular angles assessment with CT. The greater the inclination (ilia far from the tabletop in dorsal recumbency) and torsional deformity of the pelvis, the worse the acetabulum appeared. A standardized scanning protocol for acetabular morphology assessment is needed and it should consider pelvic inclination. The actual relevance of pelvic torsional deformity is not well known and it should be investigated more thoroughly.

The diagnostic value of direct CT arthrography using MDCT in the evaluation of acetabular labral tear: with arthroscopic correlation

OBJECTIVE

The purpose of this study was first, to determine the sensitivity, specificity, and accuracy of MDCT arthrography (CTA) for the diagnosis of acetabular labral tear and sulcus; second, to correlate tear types using the Lage classification system on CTA compared with the arthroscopic classification; and third, to correlate CTA localization with arthroscopic localization.

MATERIALS AND METHODS

Direct CTA was performed using 16- or 64-slice MDCT in 126 hips (124 patients) who had chronic groin pain and positive impingement test. Images were reviewed and evaluated by two experienced musculoskeletal radiologists preoperatively. CTA findings were compared with arthroscopic findings in 58 hips (56 patients) under consensus by two orthopedic surgeons.

RESULTS

Forty-one of the 58 hips were diagnosed as labral tears on CT arthrography. Forty-three of the 58 hips were shown to have a labral tear on arthroscopy. Sensitivity, specificity, and accuracy for detecting labral tear and sulcus by CTA were 90.7%, 86.7%, and 89.7%, and 93.8%, 97.6% and 96.6% respectively for observer 1, and 90.7% and 80.0%, 87.9% and 87.5%, 95.2%, and 93.1 % respectively for observer 2. Thirty-five out of 41 hips (85%) that were diagnosed with labral tear on CTA correlated substantially with arthroscopic Lage classification (kappa coefficient = 0.65). CTA and arthroscopic findings showed similar distribution patterns of the tears with most lesions located in antero- and postero-superior areas (p = 0.013).

CONCLUSION

Direct CT arthrography using MDCT may be a useful diagnostic technique in the detection of acetabular labral tear.

Anterior delayed gadolinium-enhanced MRI of cartilage values predict joint failure after periacetabular osteotomy

BACKGROUND

Several available compositional MRIs seem to detect early osteoarthritis before radiographic appearance. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been most frequently used in clinical studies and reportedly predicts premature joint failure in patients undergoing Bernese periacetabular osteotomies (PAOs).

QUESTIONS/PURPOSES

We asked, given regional variations in biochemical composition in dysplastic hips, whether the dGEMRIC index of the anterior joint would better predict premature joint failure after PAOs than the coronal dGEMRIC index as previously reported.

METHODS

We retrospectively reviewed 43 hips in 41 patients who underwent Bernese PAO for hip dysplasia. Thirty-seven hips had preserved joints after PAOs and six were deemed premature failures based on pain, joint space narrowing, or subsequent THA. We used dGEMRIC to determine regional variations in biochemical composition. Preoperative demographic and clinical outcome score, radiographic measures of osteoarthritis and severity of dysplasia, and dGEMRIC indexes from different hip regions were analyzed in a multivariable regression analysis to determine the best predictor of premature joint failure. Minimum followup was 24 months (mean, 32 months; range, 24-46 months).

RESULTS

The two cohorts were similar in age and sex distribution. Severity of dysplasia was similar as measured by lateral center-edge, anterior center-edge, and Tönnis angles. Preoperative pain, joint space width, Tönnis grade, and coronal and sagittal dGEMRIC indexes differed between groups. The dGEMRIC index in the anterior weightbearing region of the hip was lower in the prematurely failed group and was the best predictor.

CONCLUSIONS

Success of PAO depends on the amount of preoperative osteoarthritis. These degenerative changes are seen most commonly in the anterior joint. The dGEMRIC index of the anterior joint may better predict premature joint failure than radiographic measures of hip osteoarthritis and coronal dGEMRIC index.

LEVEL OF EVIDENCE

Level II, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Anterior impingement test for labral lesions has high positive predictive value

BACKGROUND

The anterior impingement test is intended to detect anterosuperior acetabular labral lesions. In patients treated for labral lesions its sensitivity is reportedly 95% to 100%, and in a small group of patients undergoing periacetabular osteotomy, its sensitivity was 59% and specificity 100%. However, the sensitivity, specificity, positive predictive value, and negative predict value of this test to detect these labral lesions in unselected patients with hip pain are unknown.

QUESTIONS/PURPOSES

We investigated these four parameters (1) in unselected patients with hip pain, and (2) in three subgroups of patients with dysplasia, femoroacetabular impingement (FAI), and with an intact joint space.

METHODS

We prospectively studied 69 patients (15 men and 54 women) with a mean age of 57.2 years (range, 27-81 years). One observer performed the anterior impingement test in all patients. We determined the presence or absence of an anterosuperior labral lesion with radial MRI in 107 hips (38 patients in both hips: 14 with pain, and 24 without pain). We also investigated the parameters in the three subgroups which consisted of 60 cases of dysplasia, 27 cases of FAI, and 80 cases with intact joint space; the third subgroup partially overlapped the first and second subgroups.

RESULTS

The four parameters in all hips were 50.6% (45/89), 88.9% (16/18), 95.7% (45/47), and 26.7% (16/60), respectively. Parameters in the three subgroups were similar to those of all cases.

CONCLUSIONS

Although the sensitivity of the anterior impingement test did not reach a sufficient level for detecting anterosuperior labral lesions, we believe the high positive predictive value makes the test useful.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Three-dimensional patterns of early acetabular cartilage damage in hip dysplasia; a high-resolutional CT arthrography study

OBJECTIVE

The purpose of this study was to examine the three-dimensional (3D) progression patterns of early acetabular cartilage damage in hip dysplasia using high-resolutional computed tomography (CT) arthrography.

DESIGN

Thirty-two dysplastic hips of 26 Japanese symptomatic females including 21 hips in pre-stage of osteoarthritis (Kellgren-Lawrence (K-L) grade 0; mean patient age, 32.0 years) and 11 hips in early stage of osteoarthritis (K-L grade 1 or 2; mean patient age, 32.8 years) were examined. Isotropic high-resolutional CT arthrography with an image resolution of 0.5 mm in any orthogonal direction was performed. A 3D acetabular cartilage model was generated and we evaluated distribution of cartilage thickness in 12 zones after dividing the weight-bearing area of the hip joint in radial and lateral/medial directions.

RESULTS

In pre-stage of osteoarthritis, significant differences in cartilage thickness were observed between the lateral and medial zones in all radial regions, most prominently in the antero-superior region. In early stage of osteoarthritis, no significant differences in cartilage thickness were observed, except in the most posterior region. The lateral-medial (LM) ratio was defined as cartilage thickness in the lateral zone divided by that in the medial zone, and hips with the LM ratio in the antero-superior region of <1.4 had significantly more extensive involvement of labral tears than hips with the LM ratio of ≥1.4.

CONCLUSIONS

In hip dysplasia, acetabular cartilage damage was probably occurred in the antero-superior lateral area. The LM ratio may be a sensitive index to quantify early cartilage damage associated with extent of labral disorders.

First assessment of three-dimensional quantitative photoacoustic tomography for in vivo detection of osteoarthritis in the finger joints

PURPOSE

The purpose of this pilot clinical study is to assess three-dimensional (3-D) quantitative photoacoustic tomography (qPAT) for in vivo detection of osteoarthritis (OA) in the finger joints.

METHODS

All subject data were handled in compliance with the rules and regulations concerning the privacy and security of protected health information under HIPAA. Seven female subjects (two OA patients and five healthy controls) entered the study and their distal interphalangeal (DIP) joints were examined by a 3-D photoacoustic scanner. 3-D optical absorption coefficient images of all the photoacoustically examined joints were recovered using a 3-D qPAT reconstruction algorithm.

RESULTS

The recovered quantitative photoacoustic images revealed obvious difference in the optical absorption coefficient of the joint cavity (cartilage and synovial fluid) between the OA and healthy joints. Quantitative analysis of the joints also indicated an apparent difference in the recovered joint spacing between the OA and healthy subjects.

CONCLUSION

This initial clinical evaluation suggests that it is feasible to detect osteoarthritis in the finger joints with our 3-D qPAT approach, which has paved the way to further statistically evaluate the diagnostic performance of the 3-D qPAT approach in comparison with radiography or magnetic resonance imaging (MRI) on a sample of hand osteoarthritis.

MR-based parameters as a supplement to radiographs in managing developmental hip dysplasia

BACKGROUND

Some dysplastic hips with favorable radiographic parameters fail to develop normally, suggesting that we should consider cartilaginous or soft tissue structures for further information regarding the condition of the hip. The purpose of this study was to provide a clear definition of concentric reduction in developmental dysplasia of the hip (DDH) based on magnetic resonance imaging (MRI), and to determine how radiographic and MR-based parameters could be used together to treat dysplastic hips.

METHODS

We studied range of motion (ROM)-MRI of 25 patients with unilateral hip dysplasia (mean age at the time of MR imaging, 44.1 months). Each ROM-MRI consisted of a set of bilateral hip scans in the following positions: neutral; abduction; abduction- internal rotation; abduction-internal rotation-flexion; and adduction. Before MR scanning, the 25 patients received the following primary treatments: closed reduction (n = 15; at a mean age of 14.5 months); and open reduction (n = 10; at a mean age of 10.0 months). The following new parameters appear to be useful in treating DDH: 1) the labral angle, the angle the labrum makes with the acetabulum; 2) the uncorrected labral deformity (ULD), the "residual deformity" (deflection of the labrum) when the affected labrum is freed from pressure in abduction; and 3) the zone of compressive force (ZCF), the region of the acetabulum through which the body weight acts on the femoral head.

RESULTS

A concentrically-reduced hip is one in which the labrum points downward in the neutral position, at the same angle as that of the normal side; and in which the ZCF is zone 3, the inner acetabular zone as defined herein. The ULD and the ZCF may be determined precisely as we have done, or the physician may simply observe the changes in the orientation of the labrum and compare the changes qualitatively to the unaffected side, and likewise for the medial joint space.

CONCLUSIONS

Detailed analysis of the labrum as permitted by ROM-MRI, together with acetabular index and other parameters measured from radiographs, provides important information for physicians treating childhood hip dysplasia.

High-resolution x-ray guided three-dimensional diffuse optical tomography of joint tissues in hand osteoarthritis: morphological and functional assessments

PURPOSE

The aim of this study was to investigate the potential use of multimodality functional imaging techniques to identify the quantitative optical findings that can be used to distinguish between osteoarthritic and normal finger joints.

METHODS

Between 2006 and 2009, the distal interphalangeal finger joints from 40 female subjects including 22 patients and 18 healthy controls were examined clinically and scanned by a hybrid imaging system. This system integrated x-ray tomosynthetic setup with a diffuse optical imaging system. Optical absorption and scattering images were recovered based on a regularization-based hybrid reconstruction algorithm. A receiver operating characteristic curve was used to calculate the statistical significance of specific optical features obtained from osteoarthritic and healthy joints groups.

RESULTS

The three-dimensional optical and x-ray images captured made it possible to quantify optical properties and joint space width of finger joints. Based on the recovered optical absorption and scattering parameters, the authors observed statistically significant differences between healthy and osteoarthritis finger joints.

CONCLUSIONS

The statistical results revealed that sensitivity and specificity values up to 92% and 100%, respectively, can be achieved when optical properties of joint tissues were used as classifiers. This suggests that these optical imaging parameters are possible indicators for diagnosing osteoarthritis and monitoring its progression.

The role of multidetector CT arthrography in the investigation of suspected intra-articular hip pathology

The aim of this study was to evaluate the role of multidetector CT (MDCT) arthrography in the diagnosis of intra-articular hip pathology. A retrospective review of 96 patients who had undergone CT hip arthrography was performed. Data regarding the presence of a labral tear, paralabral cyst, chondral loss, acetabular version, femoral morphology and fibrocystic change were collected. We detected 28 labral tears (24 anterior, 2 anterolateral, 1 lateral and 1 posterolateral). An abnormal labral-chondral transitional zone was seen in 9 patients and 4 patients had surface labral fraying. We identified three paralabral cysts. Acetabular cartilage loss was detected in 45 and femoral cartilage loss in 9 patients. An abnormal anterior femoral head and neck junction was present in 18 hips and fibrocystic change in 8. Acetabular retroversion was present in 11 hips. 63 sets of patient notes were reviewed, of which 49 were in-patients with abnormal MDCT arthrogram findings. Surgical correlation was available in 27 patients. There was a discrepancy between the findings of a labral tear in one patient (false negative, 90% sensitivity and 100% specificity) and the presence of acetabular cartilage loss (88% sensitivity and 100% specificity) and femoral cartilage loss (94% sensitivity and 100% specificity) in three patients. MDCT arthrography affords accurate detection of intra-articular hip pathology.

Cartilage thickness in the hip measured by MRI and stereology before and after periacetabular osteotomy

BACKGROUND

Untreated hip dysplasia can result in a degenerative process joint and secondary osteoarthritis at an early age. While most periacetabular osteotomies (PAOs) are performed to relieve symptoms, the osteotomy is presumed to slow or prevent degeneration unless irreparable damage to the cartilage has already occurred.

QUESTIONS/PURPOSES

We therefore determined (1) whether changes in the thickness of the cartilage in the hip occur after PAO, and (2) how many patients had an acetabular labral tear and whether labral tears are associated with thinning of the cartilage after PAO.

PATIENTS AND METHODS

We prospectively followed 22 women and four men with hip dysplasia with MRI before PAO and again 1 year and 2(1/2) years postoperatively to determine if cartilage thinning (reflecting osteoarthritis) occurred. The thickness of the femoral and acetabular cartilage was estimated with a stereologic method. Three and one-half years postoperatively, 18 of 26 patients underwent MR arthrography to investigate if they had a torn acetabular labrum.

RESULTS

The acetabular cartilage thickness differed between 1 and 2(1/2) years postoperatively (preoperative 1.40 mm, 1 year postoperatively 1.47 mm, and 2(1/2) years postoperatively 1.35 mm), but was similar at all times for the femoral cartilage (preoperative 1.38 mm, 1 year postoperatively 1.43 mm, and 2(1/2) years postoperatively 1.38 mm.) Seventeen of 18 patients had a torn labrum. The tears were located mainly superior on the acetabular rim.

CONCLUSION

Cartilage thickness 2(1/2) years after surgery compared with preoperatively was unchanged indicating the osteoarthritis had not progressed during short-term followup after PAO.

Acetabular labral tears

Acetabular labral tears rarely occur in the absence of a structural osseous abnormality. Labral tears are frequently associated with lesions of acetabular cartilage such as delamination. Hip arthroscopy is the preferred operative approach in the treatment of labral injuries in the absence of substantial structural osseous abnormalities.

Osteoarthritis: current role of imaging

Osteoarthritis (OA) is the most prevalent joint disease; it is increasingly common in the aging population of Western society and has a major health economic impact. Despite surgery and symptom-oriented approaches there is no efficient treatment. Conventional radiography has played a role in the past in confirming diagnosis and demonstrating late bony changes and joint space narrowing. MRI has become the method of choice in large research endeavors and may become important for individualized treatment planning. This article focuses on radiography and MRI, with insight into other modalities, such as ultrasound, scintigraphy, and CT. Their role in OA diagnosis, follow-up, and research is discussed.

Relationships among measurements obtained by use of computed tomography and radiography and scores of cartilage microdamage in hip joints with moderate to severe joint laxity of adult dogs

OBJECTIVE

To evaluate correlations among measurements on radiographic and computed tomography (CT) images with articular cartilage microdamage in lax hip joints of dogs.

ANIMALS

12 adult mixed-breed hounds.

PROCEDURES

Pelvic CT and radiography were performed. Hip joints were harvested following euthanasia. Orthopedic Foundation for Animals (OFA) and PennHIP radiograph reports were obtained. Norberg angle (NA) and radiographic percentage femoral head coverage (RPC) were determined. Center-edge angle (CEA), horizontal toit externe angle (HTEA), ventral acetabular sector angle (VASA), dorsal acetabular sector angle (DASA), horizontal acetabular sector angle (HASA), acetabular index (AI), and CT percentage femoral head coverage (CPC) were measured on 2-dimensional CT images. Femoral head-acetabular shelf percentage was measured on sagittal 3-dimensional CT (SCT) and transverse 3-dimensional CT (TCT) images. Light microscopy was used to score joint cartilage. Relationships of OFA confirmation and PennHIP osteoarthritis scores with radiography, CT, and cartilage variables and relationships of cartilage scores with radiography and CT measurements were evaluated with Spearman rank correlations. Pearson correlation was used for relationships of distraction index (DI) with radiography, CT, and cartilage variables.

RESULTS

Significant relationships included PennHIP osteoarthritis score with cartilage score, CEA, HTEA, DASA, AI, CPC, and TCT; OFA confirmation score with cartilage score, NA, RPC, CEA, HTEA, DASA, AI, CPC, and TCT; cartilage score with NA, RPC, CEA, HTEA, DASA, HASA, AI, and TCT; and DI with cartilage score, CEA, HTEA, DASA, HASA, AI, and CPC.

CONCLUSIONS AND CLINICAL RELEVANCE

CT appeared to be a valuable imaging modality for predicting cartilage microdamage in canine hip joints.