MR-arthrography in superior instability of the shoulder: correlation with arthroscopy

Purpose. This study was undertaken to evaluate magnetic resonance (MR) arthrography in the detection and classification of lesions that may cause superior instability. Materials and methods. Forty-two consecutive patients with clinical signs of chronic superior instability of the shoulder underwent MR arthrography followed by arthroscopic surgery. For each patient we retrospectively reviewed the MR arthrography and surgical findings. Results. We detected 31 superior labral anterior posterior (SLAP) lesions, all confirmed on arthroscopy with three cases of underestimation: in the detection of SLAP lesions, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of MR arthrography were 100%; in the evaluation of the type of SLAP lesion, sensitivity was 100%, specificity was 78.5%, accuracy was 92.8%, PPV was 71.7% and NPV was 100%. All cases of capsular laxity (13/42) and biceps tendon lesions (3/42) were confirmed on arthroscopy with sensitivity, specificity, accuracy, PPV and NPV of 100%. Eleven cuff lesions were detected on MR arthrography, 10 of which confirmed at arthroscopy: sensitivity was 100%, specificity was 96.8%, accuracy was 97.6%, PPV was 90.9% and NPV was 100%. Associated lesions were found in 38/42 patients. Conclusions. Superior instability is frequently associated with different anatomical variants or pathological conditions, such as SLAP lesions. The role of MR arthrography is to describe the key features of lesions affecting the superior portion of the shoulder, including location, morphology, extent, and associated injuries and

Obiettivo. Scopo del presente lavoro è stato valutare il ruolo dell’artro-risonanza magnetica (RM) nell’identificazione e nella classificazione delle lesioni che possono essere alla base dell’instabilità superiore di spalla. Materiali e metodi. Quarantadue pazienti consecutivi con segni clinici di instabilità superiore cronica di spalla sono stati sottoposti ad artro-RM e successiva artroscopia chirurgica. Per ogni paziente abbiamo retrospettivamente considerato i reperti artro-RM e i reperti artroscopici. Risultati. Abbiamo riscontrato 31 lesioni del labbro glenoideo superiore da anteriore a posteriore (SLAP lesions), tutte confermate all’esame artroscopico con 3 casi di sottostima del grado di lesione: nella individuazione delle SLAP lesions la sensibilità, specificità, accuratezza, valore predittivo positivo (VPP) e valore predittivo negativo (VPN) dell’artro-RM sono risultati del 100%; nella valutazione del tipo di SLAP lesion la sensibilità è stata del 100%, la specificità del 78,5%, l’accuratezza del 92,8%, il VPP del 71,7% e il VPN del 100%. Tutti i casi di lassità capsulo-legamentosa (13/42) e di lesione del tendine del capo lungo del bicipite (3/42) sono stati confermati all’artroscopia con sensibilità, specificità, accuratezza, VPP e VPN del 100%. Delle 11 lesioni dei tendini della cuffia dei rotatori diagnosticate con artro-RM, 10 sono state confermate artroscopicamente con sensibilità del 100%, specificità del 96,8%, accuratezza del 97,6%, VPP del 90,9% e VPN del 100%. Lesioni associate sono state diagnosticate in 38/42 pazienti.