A semi-automated quantitative CT method for measuring rotator cuff muscle degeneration in shoulders with primary osteoarthritis

Abstract

a b s t r a c tBackground: Rotator cuff muscle degeneration is an important parameter to consider when planning shoulder arthroplasty. Hypothesis: We hypothesized that rotator cuff muscle degeneration is correlated with scapulohumeral subluxation in patients planned for anatomical total shoulder arthroplasty (TSA). Materials and methods: We developed a semi-automated quantitative CT method to measure rotator cuff muscle degeneration, and retrospectively analyzed 107 preoperative shoulder CT scans of patients with primary osteoarthritis. On a standardized sagittal-oblique CT slice perpendicular to the scapular axis, two observers measured the cross-sectional areas of residual rotator cuff muscle tissues, normalized by the estimated area of healthy muscles. Muscle degeneration was quantified in a semi-automated manner, and divided into atrophy and fatty infiltration. Scapulohumeral subluxation was determined in 3D as the distance between the humeral head center and the glenoid surface center, projected on the same CT slice, and normalized by the humeral head radius. We tested all potential correlations between muscle degeneration and scapulohumeral subluxation. Results: Muscle degeneration, primarily due to atrophy, predominated in the supraspinatus; it varied from 0.8% to 88.8%. Scapulohumeral subluxation varied from 2.5% to 72.9%, and was mainly in a posterior and postero-superior orientation. There was a significant but weak correlation between the amount of subluxation and both supraspinatus (R = 0.207, P = 0.032) and infraspinatus (R = 0.225, P = 0.020) degeneration. Inter-and intra-observer reproducibility of muscle degeneration measurements were both excellent respectively). Conclusion: This new semi-automated CT method allows to quantitatively and reproducibly measure rotator cuff muscle degeneration in shoulders with primary osteoarthritis. Muscle degeneration is weakly correlated with scapulohumeral subluxation in patients planned for anatomical TSA. Level of evidence: Level IV. Type of study: Diagnostic retrospective study.

Deep learning for the rapid automatic quantification and characterization of rotator cuff muscle degeneration from shoulder CT datasets

“…In particular, muscle degeneration parameters such as fatty infiltration and atrophy influence surgical decision-making and overall patient management [4,5]. Although magnetic resonance imaging (MRI) offers higher contrast resolution for the evaluation of soft tissues, computed tomography (CT) still allows for the detailed quantitative analysis of muscles, distinguishing between muscle, fat, and bone tissues using specific Hounsfield unit (HU) thresholds [6][7][8]. Furthermore, CT is widely available, fast, and well accepted by patients, and this examination is increasingly being used in the imaging evaluation of glenohumeral osteoarthritis and preoperative planning of shoulder arthroplasty [9][10][11].…”

“…In clinical practice, the status of RC muscles is currently assessed using qualitative and/or semi-quantitative methods, most notably Thomazeau's occupation ratio [12] or Zanetti's tangent sign [13] for supraspinatus muscle atrophy and the Goutallier classification for fatty infiltration [1], which are all fast and easy to use but also only moderately accurate and/or reliable [14,15]. More robust and accurate quantitative CT techniques have been developed but have not yet established themselves in increasingly busy clinical workflows, mainly because of time constraints [6,7]. Automation of such techniques would make them clinically viable and could further promote the use of CT as the onestop-shop imaging prior to shoulder replacement surgery.…”

Correction to: Qualitative and quantitative analysis of glenoid bone stock and glenoid version: inter-reader analysis and correlation with rotator cuff tendinopathy and atrophy in patients with shoulder osteoarthritis

“…However, we wanted to study both CT and MRIs in the same patients to evaluate both static and dynamic stabilizers of the shoulder joint, which has not been done previously. The inclusion of patients with only CT scans would have increased sample size, and using published protocols, information on the rotator cuff muscles could have been obtained, but we thought it prudent to include tendinous integrity to examine all possible anatomic effectors of shoulder stability and wear simultaneously, despite reduced sample size, to avoid misinterpreting any potential relationships [25,26]. We were also limited by the cross-sectional nature of the study.…”

A Robotic Glenohumeral Simulator for Investigating Prosthetic Implant Subluxation

“…Compared to existing simulators, this novel simulator used a set of orthonormal actuators, as suggested by Ref. [31], but in addition had the ability to generate actuated rotations over two axis, which were not produced with some other robotic simulators [10,21,22]. Moreover, unlike existing simulators [24,32] where the force was limited (e.g., to 200 N), it was possible to produce enough load on the prosthesis (e.g., up to 2 kN) to simulate situations found in diverse activities of daily living.…”

“…Subluxation can occur in any orientation, and may or may not be associated with rotator cuff tendon tears or osteoarthritis [8]. Rotator cuff muscle degeneration may induce joint instability and eventually asymmetric glenoid loading after anatomic TSA [9][10][11].…”