Acromion stress fracture is associated with poor intraoperative bone quality and rotator cuff arthropathy following reverse shoulder arthroplasty
Poster #: 084
Session/Time: A
Author:
Zachary Ross Krumm, BS
Mentor:
Justin William Griffin, MD
Research Type: Clinical Research
Abstract
INTRODUCTION:
Reverse total shoulder arthroplasty (RSA) is the most commonly performed shoulder arthroplasty worldwide. RSA has been demonstrated to improve shoulder pain and dysfunction for those with various shoulder pathologies including rotator cuff arthropathy. A common complication of RSA is a stress fracture to the scapula, specifically the acromion process or scapular spine. Known risk factors for scapular stress fracture following RSA are rotator cuff arthropathy (RC arthropathy) as the primary diagnosis, female sex, osteoporosis, and inflammatory arthritis. The purpose of this study is to identify influence of intraoperative factors that increase the risk of scapular stress fractures following RSA so that better predictions can be made for who is likely to suffer an acromion stress fracture. This study hypothesizes that there will be an increased risk of stress fracture with poor bone quality, female sex, shorter height.
METHODS:
A retrospective analysis was performed of patients who underwent RSA by a single surgeon between 2017 and 2022. Patients with minimum 2-years of follow-up who underwent RSA with a lateralized 135 degree inlay design were included. Exclusion criteria include RSA indication of fracture, lack of 3-month minimum post-operative radiographs, revision arthroplasty, or those who sustained a postoperative traumatic fracture. Collected variables included patient age, sex, height, weight, BMI, smoking status, comorbidities, prior shoulder surgery history, operative diagnoses, implant characteristics, and intraoperative bone quality assessment. Statistical analyses were performed using JMP Student Edition 18 with alpha set at .05 to denote a statistically significant difference. Chi-square and Fisher's Exact Tests assessed the relationship between categorical variables and the development of a scapular stress fracture. Nominal logistic regression was performed for continuous variables. This study presents preliminary findings as part of an ongoing multicenter study.
RESULTS:
283 patients (age 73.7 ± 7.7 years, 59.7% Male, 40.3% Female) were treated with RSA and included in the final analysis. From 2017 to 2022, 11 patients (3.9%) suffered a scapular stress fracture (Acromion process, 10 patients, 3.5%; Scapular Spine, 1 patient, 0.4%). Notation of intraoperative poor bone quality where the bone was soft and/or could not support a press fit (P=.018) and primary diagnosis of RC Arthropathy (P=.037) were significantly associated with development of a scapular stress fracture. All other variables were found to not have statistical significance.
CONCLUSION:
Intraoperative notation of poor bone quality is a measure by which surgeons can expect a patient to be at increased risk of developing a scapular stress fracture. Additionally, having the indication of rotator cuff arthropathy is a risk factor for developing scapular stress fractures. Aggregation of multi-site data may shed further light on risk factors associated with scapular stress fractures allowing surgeons to potentially vary factors to decrease risk.
Reverse total shoulder arthroplasty (RSA) is the most commonly performed shoulder arthroplasty worldwide. RSA has been demonstrated to improve shoulder pain and dysfunction for those with various shoulder pathologies including rotator cuff arthropathy. A common complication of RSA is a stress fracture to the scapula, specifically the acromion process or scapular spine. Known risk factors for scapular stress fracture following RSA are rotator cuff arthropathy (RC arthropathy) as the primary diagnosis, female sex, osteoporosis, and inflammatory arthritis. The purpose of this study is to identify influence of intraoperative factors that increase the risk of scapular stress fractures following RSA so that better predictions can be made for who is likely to suffer an acromion stress fracture. This study hypothesizes that there will be an increased risk of stress fracture with poor bone quality, female sex, shorter height.
METHODS:
A retrospective analysis was performed of patients who underwent RSA by a single surgeon between 2017 and 2022. Patients with minimum 2-years of follow-up who underwent RSA with a lateralized 135 degree inlay design were included. Exclusion criteria include RSA indication of fracture, lack of 3-month minimum post-operative radiographs, revision arthroplasty, or those who sustained a postoperative traumatic fracture. Collected variables included patient age, sex, height, weight, BMI, smoking status, comorbidities, prior shoulder surgery history, operative diagnoses, implant characteristics, and intraoperative bone quality assessment. Statistical analyses were performed using JMP Student Edition 18 with alpha set at .05 to denote a statistically significant difference. Chi-square and Fisher's Exact Tests assessed the relationship between categorical variables and the development of a scapular stress fracture. Nominal logistic regression was performed for continuous variables. This study presents preliminary findings as part of an ongoing multicenter study.
RESULTS:
283 patients (age 73.7 ± 7.7 years, 59.7% Male, 40.3% Female) were treated with RSA and included in the final analysis. From 2017 to 2022, 11 patients (3.9%) suffered a scapular stress fracture (Acromion process, 10 patients, 3.5%; Scapular Spine, 1 patient, 0.4%). Notation of intraoperative poor bone quality where the bone was soft and/or could not support a press fit (P=.018) and primary diagnosis of RC Arthropathy (P=.037) were significantly associated with development of a scapular stress fracture. All other variables were found to not have statistical significance.
CONCLUSION:
Intraoperative notation of poor bone quality is a measure by which surgeons can expect a patient to be at increased risk of developing a scapular stress fracture. Additionally, having the indication of rotator cuff arthropathy is a risk factor for developing scapular stress fractures. Aggregation of multi-site data may shed further light on risk factors associated with scapular stress fractures allowing surgeons to potentially vary factors to decrease risk.