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 quadrant 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 quadrant compartment joint volumes; anteroinferior, anterosuperior, posterosuperior and posteroinferior). 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 quadrant compartments, the anteroinferior (Sc: Pearson coefficient, 0.26, p = 0.0199; ERs: Pearson coefficient, 0.23, p = 0.0336; ER90: Pearson coefficient, 0.25, p = 0.0246; IRb: Pearson coefficient, 0.26, p = 0.0168) and posterosuperior (Sc: Pearson coefficient, 0.24, p = 0.029; ER90: Pearson coefficient, 0.29, p = 0.008; IRb: Pearson coefficient, 0.22, p = 0.0491) and posteroinferior (Sc: Pearson coefficient, 0.30, p = 0.0064; ER90: Pearson coefficient, 0.29, p = 0.0072) showed moderate correlations with each shoulder motion.

Conclusion: Total joint volume, anteroinferior compartment joint volume, posterosuperior compartment joint volume and posteroinferior compartment joint volume were related to postoperative ROM after ARCR. Perioperative methods to increase the joint volume, especially the anteroinferior, posterosuperior and posteroinferior parts of the capsule may prevent postoperative stiffness after ARCR.

Level of evidence: Level III; Retrospective Case-Control Study.

Keywords: Arthrography; Arthroscopy; Multidetector Computed Tomography; Rotator Cuff Injuries; Shoulder; Shoulder Joint.

Fig. 1

Patient flow chart showing the inclusion and exclusion criteria used in this study

Fig. 2

Registration of three scapular landmarks (angular inferior, trigonum scapulae, and glenoid center) as fiducials before reconstruction. Scapular plane (green plane in the lower left image, green line in the upper left and lower right images): plane that passes through the three scapular landmarks. Axial plane (red plane in the upper left image, red line in the lower right and lower left images): plane that is perpendicular to the scapular plane. Sagittal plane (yellow plane in the lower right image, yellow line in the upper left and lower left images): plane that is orthogonal to the scapular and axial planes

Fig. 3

Separation of joint portion of image from others in semi-automated manner. If additional modification was needed, further manual erasing and segmentation were performed (upper right, lower left, and lower right images). When separation was performed appropriately, a 3D image of the segmented joint was generated (upper right image). The total joint volume was then calculated via the “Segment statistics” module

Fig. 4

Further separation of the total joint volume into each quadrant compartment joint volume performed in the scapular sagittal plane. The figure shows that the joint portion was separated into inferior compartment and then posteroinferior joint portions. Thereafter, calculation of the separated joint volume was performed via the “Segment statistics” module

Fig. 5

Scatter matrix of the relationship between the total joint volume (Vol.TJ) and each shoulder motion (Sc: scaption, ERs: external rotation on side, ER90: external rotation at 90°, IRb: internal rotation on back). The Vol.TJ showed a moderately positive correlation with each of the four shoulder motions

Fig. 6

Scatter matrix of the relationship between each quadrant compartment joint volumes (Vol. anteroinferior, Vol.anterosuperior, Vol.Posterosuperior, Vol.Posteroinferior) and each shoulder motion (Sc: scaption, ERs: external rotation on side, ER90: external rotation at 90°, IRb: internal rotation on back). The Vol. anteroinferior, Vol.Posterosuperior, Vol.Posteroinferior showed a moderately positive correlation with each of the four shoulder motions

Fig. 7

A schematic diagram showing the shoulder joint volume affected by postoperative tightening in a specific movement. Among the quadrant (AIQ: Anteroinferior quadrant, ASQ: Anterosuperior quadrant, PSQ: Posterosuperior quadrant, PIQ: Posterosuperior quadrant), the affected area in specific joint motion are filled in blue