RPS 1610 - Knee and lower extremities

Purpose:

To evaluate the diagnostic accuracy of axial strain elastography (ASE) for clinically diagnosed patellar tendinopathy (PTP) in youth basketball players.

Methods and materials:

52 participants (23 with PTP) were recruited from local youth basketball programs in 2016/17 and underwent sonographic assessment of bilateral patellar tendons, including ASE. Sonographers/sonologists were blinded to the case-control status of participants (PTP unilateral/PTP bilateral/no PTP). Images were partitioned, randomised, and archived for interpretation by two fellowship-trained musculoskeletal radiologists.

Using a graduated colour strain map (red-yellow-green-blue), two raters evaluated axial strain elastograms of the proximal patellar tendon and recorded tendons as ‘soft’(>2/3 red), ‘hard’(>2/3 blue), or ‘intermediate' (neither ‘hard’ nor ‘soft’). 'Soft’ tendons were considered pathologic and cross-tabulated with clinically diagnosed PTP and controls to calculate accuracy, sensitivity, and specificity. The agreement was assessed between raters.

Results:

104 patellar tendons were scanned with ASE. 9 nondiagnostic exams were excluded, leaving 95 tendons for assessment. The inter-rater reliability was moderate (Kappa=0.491). The percent agreement was 76.8%. Of disagreements, 18/22 (81.8%) related to differences between classifying a tendon as 'soft' versus 'intermediate'. For reader 1, the accuracy of ASE compared to the clinical evaluation was 53% (42%-63%), sensitivity was 18% (7%-35%), and specificity was 71 (58%-82%). For reader 2, accuracy was 59% (48%-69%), sensitivity was 24% (11%-42%), and specificity was 77% (65%-87%).

Conclusion:

ASE classification of tendons as 'soft', 'hard', or 'intermediate' stiffness had moderate inter-rater reliability. Further standardisation of definitions regarding ASE classification of tendons as 'normal' or 'pathologic' could improve inter-rater reliability.

As an isolated instrument, the accuracy of ASE for clinically diagnosed patellar tendopathy was poor.

Limitations:

B-mode images visible on ASE elastograms could bias the reader.

Ethics committee approval

Local institutional ethics approval. Each participant provided written consent.

Funding:

NBA/GE Orthopedics and Sports Medicine Collaboration Grant on Tendinopathy. Sport Injury Prevention Research Centre is supported by the International Olympic Committee.

Purpose:

To compare intra- and inter-rater reliability of a new scale to the international knee documentation committee (IKDC) scale for assessing radiographic osteoarthritis (OA) in anterior cruciate ligament (ACL) deficient subjects.

Methods and materials:

Preoperative/postoperative weight-bearing, bilateral posteroanterior semi-flexed radiographs from 44 subjects with ACL deficiency were presented as standard unblinded, showing surgical tunnels/hardware with the affected knee identified, and blinded, surgical tunnels/hardware digitally removed with the affected knee not identified. Radiographs were randomised and independently assessed by 3 raters for OA using a new scale and the IKDC scale on two occasions.

The new scale separately evaluates joint space narrowing (JSN), joint space uniformity (JSU), and osteophytes for both medial and lateral tibiofemoral compartments with a comparison to the unaffected side. JSN was graded as normal, detectable, obvious <50%, obvious >50%, and bone-on-bone, JSU as uniform/non-uniform, and osteophytes as present/absent.

Cohen's and Fleiss kappa statistics were used to measure the intra- and inter-rater reliability of the new and IKDC scales.

Results:

Intra-rater reliability was moderate to substantial for the new scale and IKDC, except fair reliability for one rater (unblinded radiographs) for lateral tibiofemoral joint uniformity. Kappa values were statistically significant (p<0.01). Inter-rater reliability ranged from slight to substantial for all categories of the new scale with statistically significant Kappa values (p<0.05), except for agreement on lateral osteophytes (standard unblinded). For both scales, intra- and inter-rater reliability was higher for blinded radiographs.

Conclusion:

Intra-rater reliability of the new OA scale for ACL-deficient knees is moderate to substantial and the same or better than IKDC. Inter-rater reliability for JSN is comparable to IKDC. Blinding surgical tunnels/hardware and the affected side may remove rater biases when assessing radiographic OA.

Limitations:

The comparison to unaffected knees assumes the knee is normal.

Ethics committee approval

The study received local ethics board approval. Informed written consent was obtained.

Funding:

Grant funding from Workers' Compensation Board, Alberta.

Purpose:

To study the natural history of new horizontal meniscal tears and to determine if they are associated with the progression of cartilage degeneration in individuals at risk for or with mild to moderate knee osteoarthritis over a period of 4 years.

Methods and materials:

Individuals who developed a new meniscal tear in the right knee were selected from the osteoarthritis initiative cohort 3T MRIs. Knee structural changes were monitored after 4 years using a modified whole-organ magnetic resonance imaging score (WORMS). Horizontal type tears were differentiated from non-horizontal tears. The control group included individuals without a meniscal tear at any timepoint matched according to BMI, gender, race, and age. Linear regression analysis was used to compare cross-sectional and longitudinal changes in cartilage WORMS scores between the groups.

Results:

41/75 subjects (54.6%) developed horizontal tears, 24 at the medial meniscus (with 17/24 (70.8%) at the posterior horn), 16 tears at the lateral meniscus (11/16 (68.75%) at the body), and one patient developed a tear in both menisci. Over 4 years, there were 30/41 (73.2%) horizontal tears but only 22/34 (64.7%) non-horizontal tears remained stable. Individuals with a new tear had higher WORMS scores at baseline (p<0.05). The overall progression of cartilage degeneration over 4 years was not significantly different between horizontal tear and control groups (WORMS total knee summary score: p>0.597, 95%CI=-0.57-1.00).

Conclusion:

New horizontal meniscal tears tended to be stable over 4 years and no statistically significant differences in overall cartilage progression were found when compared to a matched control group.

Limitations:

Only subjects developing meniscal tear over a two-year period of observation were included.

Ethics committee approval

Informed consent was reviewed and approved by institutional review boards of all participating centres.

Funding:

The osteoarthritis initiative is funded by the NIH.

Purpose:

To clinically validate a novel, deep convolutional neural network (DCNN) for the detection of surgically proven ACL tears in a large patient cohort and to analyse the effect of MR examinations from different institutions, varying protocols, and field strengths.

Methods and materials:

512 consecutive patients were retrospectively included who underwent knee MRIs either in our (n=278) or at an outside institution (n=234), followed by knee arthroscopy in our institution. All MRIs were evaluated for a full-thickness ACL tear by three radiologists and the DCNN independently. The surgical reports served as a reference standard. Statistics included sensitivity, specificity, ROC curve analysis, and kappa-statistics. A p<0.05 was considered to represent statistical significance.

Results:

An ACL tear was present in 45.7% (234/512) and absent in 54.3% (278/512) of patients. In comparison to any of the three readers, the DCNN showed a similar sensitivity of 96.1% (all p≥0.118), but a significantly lower specificity of 93.1% (all p<0.001) and area under the curve (AUC) of 0.935 (all p<0.001). Subgroup analysis showed a significantly lower sensitivity, specificity, and AUC of the DCNN for patients examined at an outside institution (92.5%, 87.1%, and 0.898) in comparison to patients examined in our institution (99.0%, 94.4%, and 0.967), with p=0.026, p=0.043, and p<0.05, respectively. No significant differences of the DCNN assessments existed regarding field strength (1.5T or 3T MRI; all p≥0.753). The agreement between the radiologists was almost perfect with kappa=0.984.

Conclusion:

In our multi-institutional cohort (different institutions, varying protocols) our DCNN detects complete ACL tears with similar sensitivity and slightly lower specificity than specialised radiologists and with a similar accuracy than published meta-analyses.

Limitations:

Possible selection bias because only patients with subsequent arthroscopic surgery were included. Only binary classification; no tear versus full-thickness tear.

Ethics committee approval

Approved by the local ethics committee.

Funding:

No funding was received for this work.

Purpose:

To compare 3D PD fat-suppressed space turbo spin-echo (TSE) and conventional 2D PD sequences at 3T MRI in the detection of meniscal tears.

Methods and materials:

Dedicated MR knee imaging of 100 sequential patients with suspected meniscal injuries was retrospectively analysed by two independent radiologists in a novel study design using both a 2D PD standard multiplanar TSE MR technique and 3D PD TSE technique. The result was compared to arthroscopic results (arthroscopy was performed after MRI study) which were considered as a gold standard test. We determined the sensitivity, specificity, and interobserver agreement for each sequence.

Results:

The 3D TSE shows statistically higher sensitivity and specificity (100% and 100%) for the detection of meniscal radial tear compared to the 2D sequence (67% and 96%). No significant difference was found between the sensitivity and specificity of both techniques regarding the detection of horizontal, longitudinal, root, flap, and bucket handle tears. There was higher interobserver agreements on 3D TSE SPACE than 2D sequences for radial, root, and bucket handle tears.

Conclusion:

At 3T MRI, the 3D PD fat-suppressed space turbo spin-echo (TSE) has higher diagnostic performance compared to the routine 2D TSE protocol for the detection of meniscal radial tears and similar results as regarding the other types of tears with the advantage of faster acquisition.

Limitations:

n/a

Ethics committee approval

Written and informed consent was obtained.

Funding:

No funding was received for this work.

Purpose:

To evaluate the added advantage of shear-wave elastography (SWE) over grey-scale sonography in the diagnosis of plantar fasciitis and to obtain a reproducible and reliable sonoelastographic shear stress cut-off value.

Methods and materials:

In this prospective case-control study, 30 consenting patients having unilateral heel pain for >6 months and clinically diagnosed as unilateral heel pain were included. Patients were examined by the lead author and a faculty radiologist by B-mode sonography (for plantar fascia thickness), followed by SWE, obtaining a colour map for shear characteristics and quantitative data (shear velocity in cm/s and shear stress in kPa) using a 1x1 cm ROI placed at the position of the highest shear on the colour map. Sensitivity and false-positive rates with extrapolated specificity, PPV, and NPV were calculated, and shear stress cut-off values were obtained using the Chi-square test and ROC curve analysis. The unaffected foot from respective cases was taken as control (normal) for the study.

Results:

Of 30 examined cases, mean thickness of plantar fascia was significantly higher (5.4 mm) in the affected foot compared to the unaffected (2.9 mm), with a standard ROC cut-off of 3.7 mm (sensitivity 93%, false-positive rate 10%). The mean shear stress in the plantar fascia on the affected side (60.1kPa) differed significantly from the unaffected side (150.7kPa). Taking 97.5kPa as the shear stress cut-off, considering affected patients having values below this cut-off, sensitivity was 81.8% and the false-positive rate was 10.6%. Extrapolated specificity, PPV, and NPV were 89.4%, 88.5%, and 83.1%. AUC was 0.91.

Conclusion:

SWE shows superior diagnostic accuracy compared to grey-scale sonography in patients with plantar fasciitis and promises the potential for routine use in addition to B-mode US for the assessment of plantar fasciitis cases.

Limitations:

A limited number of patients.

Ethics committee approval

Ethic committee approval obtained.

Funding:

No funding was received for this work.

Purpose:

Recent MRI-studies revealed that tenosynovitis in the hands is associated with rheumatoid arthritis (RA). Although the forefoot is a preferential location for RA-inflammation, it is unknown whether MRI-detected tenosynovitis at the metatarsophalangeal (MTP)-joints is associated with RA. Additionally, anatomic literature leaves it undetermined if tendons at MTP-joints are surrounded by a synovial sheath. These questions were investigated.

Methods and materials:

634 persons were included: 157 newly presenting RA-patients, 284 patients with other early arthritides, and 193 symptom-free persons. All underwent MRI of unilateral MTP (1-5)-joints. Images were scored by two independent readers for tenosynovitis, synovitis, and bone marrow oedema. Its association with RA was analysed using logistic regression. Macroscopically, 14 forefeet of donated bodies were examined at the flexor-tendons and extensor-tendons for the presence and course of tendon sheaths. Tissue surrounding tendons was injected with blue-dyed resin or silicon. The presence of a sheath was also studied by light-microscopy.

Results:

MRI-detected tenosynovitis was associated with RA (OR 2.4 (95%CI 1.5-3.8, P<0.001) for flexor and OR 3.1 (95%CI 1.9-5.2, P<0.001) for extensor tendons). The sensitivity of tenosynovitis in RA was 42%. The specificity compared to other arthritides was 78% and compared to symptom-free persons 98%. Macroscopically, all extensor and flexor tendons crossing MTP-joints demonstrated clearly demarcated sheaths surrounding tendons. Microscopy revealed a synovial sheath at flexor and extensor tendons.

Conclusion:

Flexor and extensor tendons at metatarsophalangeal-joints are surrounded by a tenosynovium. MRI-detected tenosynovitis at metatarsophalangeal-joints was associated with, and specific for, rheumatoid arthritis, both when compared to patients with other arthritides and healthy controls.

Limitations:

Our study is cross-sectional; additional longitudinal studies on the diagnostic value are needed.

Ethics committee approval

Ethics committee approval obtained.

Funding:

European Research Council and the Dutch Arthritis Foundation.

Purpose:

The increasing use of cone-beam CT to diagnose ankle and foot problems urges the development of quantitative 3D analysis tools that deliver geometrical parameters corresponding to well-known 2D counterparts. We compared estimates of geometrical parameters from both cone-beam CT and radiographs as differences can be expected between 2D and 3D analyses.

Methods and materials:

WB and non-WB cone-beam CT-images of the left and right hindfoot and forefoot were acquired on a Planmed verity cone-beam CT-scanner. Geometric analyses were performed on images of the foot in 2D using simulated radiography images and 3D using custom analysis software. Measurements included the calcaneal pitch, Meary’s angle, the angle between 1^stand 2^nd metatarsal (MTT), the talocalcaneal angle, and cuboid height.

Results:

5 patients were included with a mean age of 39.6 years. All measurement results were statistically different in 2D and 3D (p<0.001). The average calcaneal pitch decreased in 2D and in both 3D WB compared to non-WB results. Meary’s angle decreased in 2D measurements, however, increased using 3D measurements. The average angle between MTT1-2 increased in both approaches. During WB, the talocalcaneal angle decreased in both lateral-lateral and anterior-posterior 2D views and increased in 3D. Cuboid height decreased between non-WB and WB images by 1.3 and 6.5 mm in 2D and 3D images respectively (p<0.001).

Conclusion:

The geometric parameters evaluated in 2D were different compared to 3D, which is likely caused by over-projection and the specific point of view. We expect that 3D measurement tools are more univocal and therefore more suitable for future use. Also, switching to 3D enables advanced analysis such as obtaining joint space maps.

Limitations:

Sample-size, 2D and 3D comparisons, and multiple observers.

Ethics committee approval

n/a

Funding:

No funding was received for this work.