Influence of Joint Volume on Range of Motion after Arthroscopic Rotator Cuff Repair

Abstract

Background: Capsular contracture is a well-known etiology in the primary stiff shoulder; thus capsular contracture and resultant decreased joint volume could lead to postoperative stiffness, which is a commonly reported morbidity after arthroscopic rotator cuff repair (ARCR). The purpose of this study was (1) to quantify the joint volume (total joint volume and each half compartmental volume) using computed tomography arthrography (CTA) and (2) to demonstrate the relationship between joint volume and postoperative range of motion (ROM) after ARCR Materials and Methods: Eighty-three patients (60 ± 5.11 years, men=26, women=57) who had undergone ARCR between January 2015 to December 2020 due to small to medium full-thickness tear and followed by CTA 6 months postoperatively were retrospectively reviewed. An image reconstruction program (3D Slicer, version 4.11.2 software) was used to calculate the joint volume (total joint volume and four half compartment joint volumes; anterior, posterior, superior, and inferior). For shoulder ROM, data including scaption (Sc), external rotation on side (ERs), external rotation at 90° (ER90), and internal rotation on back (IRb) were collected 6 months postoperatively. An evaluation of the correlation between joint volume and each shoulder motion was performed. Results: There were moderate correlations between the total joint volume and each motion (Sc: Pearson coefficient, 0.32, p=0.0047; ERs: Pearson coefficient, 0.24, p=0.0296; ER90: Pearson coefficient, 0.33, p=0.0023; IRb: Pearson coefficient, 0.23, p=0.0336). Among the half compartments, the posterior half (Sc: Pearson coefficient, 0.34, p=0.0016; ERs: Pearson coefficient, 0.21, p=0.0493; ER90: Pearson coefficient, 0.37, p=0.0006; IRb: Pearson coefficient, 0.25,p=0.0217) and inferior half (Sc: Pearson coefficient, 0.31, p=0.0038; ERs: Pearson coefficient, 0.21, p=0.0483; ER90: Pearson coefficient, 0.31, p=0.0047; IRb: Pearson coefficient, 0.25, p=0.0254) showed moderate correlations with each shoulder motion. Conclusion: Total joint volume, posterior half compartment joint volume, and inferior half compartment joint volume were related to postoperative ROM after ARCR. Perioperative methods to increase the joint volume, especially the posterior part and inferior part of the capsule may prevent postoperative stiffness after ARCR. Level of Evidence: Level III; Retrospective Case-Control Study