MRI-derived Articular Cartilage Strains Predict Patient-Reported Outcomes Six Months Post Anterior Cruciate Ligament Reconstruction

Key terms

Multicontrast and Multiparametric, Magnetic Resonance Imaging, Osteoarthritis, Functional Biomechanical Imaging, Knee Joint Degeneration What is known about the subject: dualMRI has been used to quantify strains in a healthy human population in vivo and in cartilage explant models. Previously, OA severity, as determined by histology, has been positively correlated to increased shear and transverse strains in cartilage explants. What this study adds to existing knowledge: This is the first in vivo use of dualMRI in a participant demographic post-ACL reconstruction and at risk for developing osteoarthritis. This study shows that dualMRI-derived strains are more significantly correlated with patient-reported outcomes than any MRI relaxometry metric.

Background

Anterior cruciate ligament (ACL) injuries lead to an increased risk of osteoarthritis, characterized by altered cartilage tissue structure and function. Displacements under applied loading by magnetic resonance imaging (dualMRI) is a novel MRI technique that can be used to quantify mechanical strain in cartilage while undergoing a physiological load.

Purpose

To determine if strains derived by dualMRI and relaxometry measures correlate with patient-reported outcomes at six months post unilateral ACL reconstruction.

Study Design

Cohort study.

Methods

Quantitative MRI (T2, T2*, T1ρ) measurements and transverse, axial, and shear strains were quantified in the medial articular tibiofemoral cartilage of 35 participants at six-months post unilateral ACL reconstruction. The relationships between patient-reported outcomes (WOMAC, KOOS, MARS) and all qMRI relaxation times were quantified using general linear mixed-effects models. A combined best-fit multicontrast MRI model was then developed using backwards regression to determine the patient features and MRI metrics that are most predictive of patient-reported outcome scores.

Results

Higher femoral strains were significantly correlated with worse patient-reported functional outcomes. Femoral shear and transverse strains were positively correlated with six-month KOOS and WOMAC scores, after controlling for covariates. No relaxometry measures were correlated with patient-reported outcome scores. We identified the best-fit model for predicting WOMAC score using multiple MRI measures and patient-specific information, including sex, age, graft type, femoral transverse strain, femoral axial strain, and femoral shear strain. The best-fit model significantly predicted WOMAC score (p<0.001) better than any one individual MRI metric alone. When we regressed the model-predicted WOMAC scores against the patient-reported WOMAC scores, we found that our model achieved a goodness of fit exceeding 0.52.

Conclusions

This work presents the first use of dualMRI in vivo in a cohort of participants at risk for developing osteoarthritis. Our results indicate that both shear and transverse strains are highly correlated with patient-reported outcome severity could serve as novel imaging biomarkers to predict the development of osteoarthritis.

Factors Influencing Surgeon's Choice of Procedure for Anterior Shoulder Instability: A Multicenter Prospective Cohort Study

PURPOSE

To investigate preoperative factors associated with selection of surgical treatment for anterior shoulder instability.

METHODS

Patient demographics, initial physical examinations, and patient-oriented outcome questionnaires were collected prospectively from 26 shoulder surgeons at 10 sites. Symptom duration, number of dislocations, sport, history of prior stabilization procedure, Hill-Sachs/glenoid bone loss, pain level, and failure of conservative treatment were recorded. Statistical analysis was performed with Fisher's exact test and logistic regression analysis.

RESULTS

A total of 564 patients who underwent surgical treatment for anterior shoulder instability from November 2012 to June 2017 were enrolled. Of these, 426 shoulders underwent arthroscopic stabilization alone, 38 underwent arthroscopic stabilization with remplissage, 28 underwent open Bankart repair, and 72 underwent a Latarjet procedure. Predictors for undergoing Latarjet (P < .003) were symptom duration (75% had symptoms for >1 year), number of dislocations (47% had >5 dislocations), revision surgery (69%), Hill-Sachs lesion size (45% had a lesion between 11% and 20% of the humeral head), and glenoid bone loss (75% of Latarjet patients had 11% to 30% loss). Predictors for undergoing open Bankart repair (P < .001) were number of dislocations (32% had >5 dislocations), revision surgeries (54%), and glenoid bone loss (11% of open Bankart patients had 11% to 20% loss). History of prior shoulder surgery was the only significant predictor of open versus arthroscopic Bankart procedure. Prediction models showed athletes involved in high-risk sports were 2.61 times more likely to have a Latarjet (P < .01).

CONCLUSIONS

Indications for the Latarjet were: humeral and glenoid bone loss, duration of symptoms, number of dislocations, and revision stabilizations. Athletes involved in high-risk sports were more likely to undergo the Latarjet procedure, even if other predictive factors were not present. The open Bankart procedure was the least common procedure performed, with a history of prior shoulder surgery being the only predictor for use when treating recurrent instability.

LEVEL OF EVIDENCE

Level II, prospective prognostic cohort investigation.

The Incidence of Glenohumeral Bone and Cartilage Lesions at the Time of Anterior Shoulder Stabilization Surgery: A Comparison of Patients Undergoing Primary and Revision Surgery

BACKGROUND

Intra-articular glenohumeral joint changes frequently occur after shoulder instability events.

PURPOSE

(1) To compare demographic characteristics, baseline patient-reported outcomes, and intraoperative findings for patients undergoing primary or revision shoulder stabilization surgery and (2) to determine the incidence of glenohumeral bone and cartilage lesions in this population while identifying factors independently associated with these lesions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group shoulder instability database was used to identify all prospectively enrolled patients undergoing shoulder stabilization surgery for anterior instability between October 2012 and September 2016. Any patient who underwent surgery for posterior or multidirectional shoulder instability or concomitant rotator cuff repair surgery was excluded. Patient demographic characteristics, preoperative patient-reported outcomes, and intraoperative findings, including glenohumeral bone and cartilage lesions, were compared for patients undergoing primary and revision shoulder stabilization surgery. Additionally, patients with and without glenohumeral bone and cartilage lesions were compared and independent associations determined using multivariate analysis.

RESULTS

There were 545 patients available for analysis (461/545 [84.6%] primary; 84/545 [15.4%] revision). Patients undergoing revision surgery were older ( P = .001), were more frequently smokers ( P = .022), had a greater number of instability events before surgery ( P = .047), more frequently required reduction assistance ( P < .001), and had lower Short Form-36 (SF-36) Mental Component Summary ( P = .020) and Western Ontario Shoulder Instability Index (WOSI) ( P = .026) scores preoperatively. Additionally, patients undergoing revision surgery had a higher frequency of bone and cartilage lesions than those undergoing primary surgery (47.6% vs 18.4%, respectively; P < .001). Male sex, revision surgery, black race, increasing body mass index, increasing patient age, and lower preoperative SF-36 Physical Component Summary score were independently associated with the presence of glenohumeral bone and cartilage lesions at the time of shoulder stabilization surgery. Revision surgery was strongly associated with the presence of glenohumeral bone and cartilage lesions (odds ratio [OR], 4.381 [95% CI, 2.591-7.406]) and glenoid bone loss greater than 10% (OR, 9.643 [95% CI, 5.128-18.134]) or 20% (OR, 13.076 [95% CI, 5.113-33.438]) of the glenoid width.

CONCLUSION

Glenohumeral bone and cartilage lesions are common at the time of shoulder stabilization surgery, occurring more frequently in patients undergoing revision surgery as compared with primary surgery. On the basis of these findings, future prospective studies should aim to compare the clinical outcomes in these 2 groups.

Arthrographic Anatomy of the Biceps Tendon Sheath: Potential Implications for Selective Injection

The purpose of this investigation was to better define the anatomical features of the biceps tendon sheath, including the distance the sheath extends below the inferior margin of the subscapularis tendon and below the termination of the bony bicipital groove. A total of 110 magnetic resonance and computed tomography arthrograms performed during 1-year period at our institution were retrospectively reviewed, and the length of the biceps tendon sheath and distances from the inferior margin of the subscapularis tendon and from the termination of the bicipital groove to the inferior margin of the biceps tendon sheath were measured by 3 radiologists. The mean length of the biceps tendon sheath was 47.5mm. The mean distances from the inferior margin of the subscapularis tendon and from the inferior margin of the bicipital groove to the distal extent of the biceps tendon sheath were 24.5mm and 11.9mm, respectively. The relationships among these 3 anatomical measurements and biological confounders of sex and age were investigated while controlling for measurement variability. The anatomical relationships between the biceps tendon sheath and surrounding structures may have implications for needle placement when attempting to inject into the biceps tendon sheath for diagnostic or therapeutic purposes.

Biceps Tenotomy Versus Tenodesis

Long head biceps tendon is a common cause of anterior shoulder pain. Failure of conservative treatment may warrant surgical intervention. Surgical treatment involves long head biceps tenotomy or tenodesis. Several different techniques have been described for biceps tenodesis, including arthroscopic versus open and suprapectoral versus subpectoral. Most studies comparing tenodesis to tenotomy are limited by the level of evidence and confounding factors, such as concomitant rotator cuff tear. Many studies demonstrate similar outcomes for both procedures. Surgeon preference is likely more influential in choosing between tenotomy and tenodesis. Higher-powered studies are necessary to elucidate any differences in outcomes if present.

Intra- and interobserver agreement in the classification and treatment of distal third clavicle fractures

BACKGROUND

In treatment of distal third clavicle fractures, the Neer classification system, based on the location of the fracture in relation to the coracoclavicular ligaments, has traditionally been used to determine fracture pattern stability.

PURPOSE

To determine the intra- and interobserver reliability in the classification of distal third clavicle fractures via standard plain radiographs and the intra- and interobserver agreement in the preferred treatment of these fractures.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

Thirty radiographs of distal clavicle fractures were randomly selected from patients treated for distal clavicle fractures between 2006 and 2011. The radiographs were distributed to 22 shoulder/sports medicine fellowship-trained orthopaedic surgeons. Fourteen surgeons responded and took part in the study. The evaluators were asked to measure the size of the distal fragment, classify the fracture pattern as stable or unstable, assign the Neer classification, and recommend operative versus nonoperative treatment. The radiographs were reordered and redistributed 3 months later. Inter- and intrarater agreement was determined for the distal fragment size, stability of the fracture, Neer classification, and decision to operate. Single variable logistic regression was performed to determine what factors could most accurately predict the decision for surgery.

RESULTS

Interrater agreement was fair for distal fragment size, moderate for stability, fair for Neer classification, slight for type IIB and III fractures, and moderate for treatment approach. Intrarater agreement was moderate for distal fragment size categories (κ = 0.50, P < .001) and Neer classification (κ = 0.42, P < .001) and substantial for stable fracture (κ = 0.65, P < .001) and decision to operate (κ = 0.65, P < .001). Fracture stability was the best predictor of treatment, with 89% accuracy (P < .001).

CONCLUSION

Fracture stability determination and the decision to operate had the highest interobserver agreement. Fracture stability was the key determinant of treatment, rather than the Neer classification system or the size of the distal fragment.

The interaction between the whipstitch sutures of multi-strand ACL grafts and interference screw fixation

In a recent experiment examining the effect of interference screw sizing on the fixation stability of multi-strand anterior cruciate ligament grafts, we noticed a large variation in fixation strengths and attributed it to the suturing of the grafts and its interaction with the screw. We performed an experiment using interference screws for fixation of hamstring grafts within a bone tunnel model to compare how the presence of sutures affected graft fixation. We found that having sutures along the region of the graft that contacts the screw within the bone tunnel can increase graft fixation strength 100%.

Silica-induced activation of c-Jun-NH2-terminal amino kinases, protracted expression of the activator protein-1 proto-oncogene, fra-1, and S-phase alterations are mediated via oxidative stress

Crystalline silica has been classified as a group 1 human carcinogen in the lung. However, its mechanisms of action on pulmonary epithelial cells which give rise to lung cancers are unclear. Using a nontransformed alveolar type II epithelial cell line (C10), we show that alpha-quartz silica causes persistent dose-related increases in phosphorylation of c-Jun-NH2-terminal amino kinases (JNKs) that are inhibited by antioxidants (P < or = 0.05). Increases in activator protein-1 (AP-1) binding to DNA and transactivation of AP-1-dependent gene expression by silica were accompanied by increases in steady-state mRNA levels of the AP-1 family members, c-jun, junB, fra-1, and c-fos at 8 h and elevated mRNA levels of fra-1 at 24 h (P < or = 0.05). Addition of tetramethylthiourea inhibited silica-associated increases infra-1 and proportions of cells in S-phase (P < or = .05). Our findings indicate that silica induces JNK activity, AP-1-dependent gene expression, ie., fra-1, and DNA synthesis via oxidative stress. Moreover, they suggest that silica may act mechanistically as a mitogen or tumor promoter, rather than a genotoxic carcinogen, in the development of lung cancers.

Elimination of Current Dissipation in High Transition Temperature Superconductors

The relaxation of the shielding current-induced magnetic moment in YBa(2)Cu(3)O(7) thin films, which were grown in situ, is studied as a function of temperature. Although typical relaxations cause a large amount of decay in the magnetic shielding current (on the order of 10 to 20 percent for the first 1000 seconds), it is shown that this is not necessarily a serious problem for applications such as magnets operating in persistent-current modes. This is because the decay of the magnetic shielding current depends sensitively on how far away the operating current density is from the critical current density J(c). By using a quenching process the shielding current is reduced slightly below J(c) and the relaxation is dramatically reduced. A general relation between the relaxation rate at J(c) and the reduction of the relaxation rate upon lowering of the operating current is obtained and is shown to be consistent with experimental data.