Hugo Barret1, Marc-Olivier Gauci1, Tristan Langlais1, Olivier van der Meijden1, Laurie Tran2, Pascal Boileau3. 1. iULS (Institut Universitaire Locomoteur et du Sport) Hôpital Pasteur 2, University Côte d'Azur, Nice, France. 2. Department of Anesthesiology, Hôpital Pasteur 2, University Côte d'Azur, Nice, France. 3. iULS (Institut Universitaire Locomoteur et du Sport) Hôpital Pasteur 2, University Côte d'Azur, Nice, France. Electronic address: boileau.p@chu-nice.fr.
Abstract
BACKGROUND: We evaluated survival and midterm results of pyrocarbon interposition shoulder arthroplasty (PISA) in arthritic patients younger than 65 years. METHODS: Fifty-eight PISAs (InSpyre; Tornier-Wright, Bloomington, MN, USA), implanted in 56 patients between 2010 and 2015, were prospectively observed. The mean age at surgery was 52 ± 13 years. The cause was primary osteoarthritis (18), fracture sequelae (16), post-instability arthritis (15), aseptic necrosis (3), inflammatory disease (2), and failed hemiarthroplasty (4); 34 shoulders (61%) had previously undergone surgery. Glenoid erosion was assessed in 4 grades according to the Sperling classification. Humeral erosion was also assessed in 4 grades. Multivariate analysis was used to determine predisposing risk factors for both humeral and glenoid erosion. RESULTS: At a mean follow-up of 47 ± 15 months, survival rate was 90%. Six patients (10%) required conversion to reverse total shoulder prosthesis for painful glenoid erosion (n = 2) and humeral erosion with greater tuberosity stress fractures (n = 4). The mean Constant score and subjective shoulder value significantly increased from 36 ± 14 points to 70 ± 15 points and 32% ± 14% to 75% ± 19%, respectively (P < .001). Humeral medialization was observed in 78% of the cases with increased pain score. Uncorrected anteroposterior implant subluxation (12 cases) was associated with lower Constant score (50 points vs. 72 points; P = .02) and lower subjective shoulder value (53% vs. 78%; P = .002). On multivariate analysis, no risk factors for glenoid or humeral erosion were found. CONCLUSION: At midterm follow-up, PISA does not protect from progressive glenoid erosion and can lead to greater tuberosity erosion and stress fractures. Longer follow-up is required to see whether PISA survival will be superior to that of hemiarthroplasty.
BACKGROUND: We evaluated survival and midterm results of pyrocarbon interposition shoulder arthroplasty (PISA) in arthriticpatients younger than 65 years. METHODS: Fifty-eight PISAs (InSpyre; Tornier-Wright, Bloomington, MN, USA), implanted in 56 patients between 2010 and 2015, were prospectively observed. The mean age at surgery was 52 ± 13 years. The cause was primary osteoarthritis (18), fracture sequelae (16), post-instability arthritis (15), aseptic necrosis (3), inflammatory disease (2), and failed hemiarthroplasty (4); 34 shoulders (61%) had previously undergone surgery. Glenoid erosion was assessed in 4 grades according to the Sperling classification. Humeral erosion was also assessed in 4 grades. Multivariate analysis was used to determine predisposing risk factors for both humeral and glenoid erosion. RESULTS: At a mean follow-up of 47 ± 15 months, survival rate was 90%. Six patients (10%) required conversion to reverse total shoulder prosthesis for painful glenoid erosion (n = 2) and humeral erosion with greater tuberosity stress fractures (n = 4). The mean Constant score and subjective shoulder value significantly increased from 36 ± 14 points to 70 ± 15 points and 32% ± 14% to 75% ± 19%, respectively (P < .001). Humeral medialization was observed in 78% of the cases with increased pain score. Uncorrected anteroposterior implant subluxation (12 cases) was associated with lower Constant score (50 points vs. 72 points; P = .02) and lower subjective shoulder value (53% vs. 78%; P = .002). On multivariate analysis, no risk factors for glenoid or humeral erosion were found. CONCLUSION: At midterm follow-up, PISA does not protect from progressive glenoid erosion and can lead to greater tuberosity erosion and stress fractures. Longer follow-up is required to see whether PISA survival will be superior to that of hemiarthroplasty.