The implications of the glenoid angles and rotator cuff status in patients with osteoarthritis undergoing shoulder arthroplasty

Abstract

Background The success of shoulder arthroplasty, both reverse and anatomical, depends on correcting the underlying glenoid deformity especially in patients with an osteoarthritis. We hypothesized that the distribution of glenoid version and especially inclination are underestimated in the shoulder arthritis population, and also that superior glenoid inclination can be detected through 3-dimensional (3D) software program of computed tomography (CT) to a greater proportion in patients with rotator cuff insufficiency, but also in patients with osteoarthritis with an intact rotator cuff. Because of the influence of rotator cuff imbalance on secondary glenoid wear the values of the critical shoulder angle (CSA) and the fatty infiltration of the rotator cuff are further analyzed. The aim of our study is to determine; 1) the distribution of glenoid inclination and version; 2) the relationship between glenoid inclination, version, the critical shoulder angle (CSA) to the status of the rotator cuff; 3) the proportion of patients with both an intact rotator cuff and a superior inclination greater than 10°. Methods A total of 231 shoulders were evaluated with X-ray images, 3-dimentional (3D) software program of computed tomography (CT), and magnetic resonance imaging. The cohort was divided into 3 groups according to their inclination angles and also grouped as intact-rotator cuff and torn-cuff group. Results The median (min/max) values for the 231 shoulders were 8° (− 23°/56°) for the inclination angle, − 11°(− 55°/23°) for the version angle, and 31.5°(17.6°/61.6°) for the CSA. The majority of the glenoids were found to show posterior-superior erosion. Glenoid inclination angle and CSA were significantly higher in torn-cuff group when compared with intact-cuff group (P < 0.001, both). The rotator cuff tears were statistically significant in high inclination group than low inclination group and no inclination group (p < 0.001). In the high inclination group, 41 of 105 (39%) shoulders had an intact rotator cuff, in about 18% of all shoulders. Conclusion Our findings show that 3D evaluation of glenoid inclination is mandatory for preoperative planning of shoulder replacement in order to properly assess superior inclination and that reverse shoulder arthroplasty may be considered more frequently than as previously expected, even when the rotator cuff is intact. Level of evidence Level III.

CT-based and morphological comparison of glenoid inclination and version angles and mineralisation distribution in human body donors

“…Based on the literature (see above), we found inclination angles ≤10° in glenoids with mineralisation distribution patterns considered as healthy [ 45 ], frequently combined with healthy morphology and low 3D-CT osteoarthritis gradings. In agreement, high inclination was recently grouped as ≥10°, low inclination between 0° to 10° and no inclination ≤0° [ 39 ].…”

“…Osteoarthritis is one of the most common diseases worldwide, causing pain and severe restrictions of the range of motion and quality of life, particularly in the elderly [ 39 , 52 , 54 ]. Progressive disease causes extensive morphological changes in articular cartilage and subchondral bone, which may result in narrowed joint gap, subchondral sclerosis, osteophytes and deformation of the glenoid including alterations of glenoid angles.…”

“…Progressive disease causes extensive morphological changes in articular cartilage and subchondral bone, which may result in narrowed joint gap, subchondral sclerosis, osteophytes and deformation of the glenoid including alterations of glenoid angles. An ideal range is not clearly defined to date, but the geometry of the glenoid may predispose for alterations [ 15 , 17 , 36 , 39 , 55 ]. To achieve an optimal treatment outcome, e.g., positioning of the prosthetic glenoid component, a profound knowledge on optimal geometry, particularly the glenoid angles, and bone mineralisation is essential [ 3 , 15 – 17 , 29 , 33 , 39 ].…”

“…An ideal range is not clearly defined to date, but the geometry of the glenoid may predispose for alterations [ 15 , 17 , 36 , 39 , 55 ]. To achieve an optimal treatment outcome, e.g., positioning of the prosthetic glenoid component, a profound knowledge on optimal geometry, particularly the glenoid angles, and bone mineralisation is essential [ 3 , 15 – 17 , 29 , 33 , 39 ].…”

A lower critical coracoid process angle is associated with type-B osteoarthritis: a radiological study of normal and diseased shoulders

“… 14 , 54 This eccentric wear results in formation of a biconcave neo-glenoid and an acquired pathological glenoid retroversion (RV). 11 , 30 , 36 , 40 , 44 Other axial plane variations of scapular morphology associated with type-B OA have not yet been reported although abnormal coracoid morphology has been associated with glenoid dysplasia in obstetric brachial plexus palsy (OBPP). 26 , 35 , 38 , 46 , 51 , 58 …”