Shoulder arthroplasty in osteoarthritis: correlation between function and radiographic parameters

OBJECTIVES: To evaluate the correlation between radiographic parameters and functional assessments of patients with osteoarthritis of the shoulder who underwent shoulder arthroplasty and to describe the functional outcomes of this procedure in our institution. METHODS: We evaluated 21 patients (22 shoulders) who underwent shoulder arthroplasty between 1998 and 2010 and with a minimum follow-up of 12 months. Clinical evaluation was performed using the Constant-Murley scale, UCLA, EVA and by measuring the active motion. We analysed preoperative (distance between the top of the head and the humerus and the acromion, superior migration, neck angulation, medial "offset", subluxation, glenoid erosion) and postoperative radiographic parameters (rod inclination, migration of components and loosening). RESULTS: Patients showed significant improvement in all parameters: flexion (p = 0.0083), abduction (p = 0.0266), external rotation (p = 0.0062), Constant-Murley (p = 0.0001 ), UCLA (p <0.0001) and VAS (p = 0.0002). The superior migration of the humerus showed a significant correlation with UCLA and Constant-Murley scores (p = 0.0480 and p = 0.0110, respectively). The other radiographic parameters showed no correlation with the clinical outcomes. CONCLUSION: The superior migration of the humerus is related to worse clinical scores. Level of Evidence IV, Case Series.