Comparison of Dynamic In Vivo Shoulder Kinematics Before and After Superior Capsular Reconstruction for Irreparable Rotator Cuff Tears

Abstract

Background: Superior capsular reconstruction (SCR) is an alternative surgical option for young active patients with irreparable rotator cuff tears without arthritis. Although cadaveric studies have shown superior stability of the humerus, it remains unclear whether the humerus migrates superiorly after SCR in vivo. Purpose: To analyze the change in glenohumeral translation in patients before and after SCR. Study Design: Case series; Level of evidence, 4. Methods: A total of 22 patients who underwent SCR by a single surgeon for irreparable rotator cuff tears were included. Among them, 14 patients had intact grafts, and 8 patients were diagnosed with retears on 1-year postoperative magnetic resonance imaging (MRI) scans. Fluoroscopy was performed in all patients preoperatively and at 3-month, 6-month, and 1-year follow-up. Moreover, 3-dimensional bone models from computed tomography, MRI, and fluoroscopic scans during scapular plane abduction of the shoulder joints were analyzed. Results: In the intact graft group, 3-dimensional dynamic shoulder kinematics at 6 months ( P = .026) and 1 year ( P = .032) postoperatively showed statistically significant decreases in humeral head superior translation compared with preoperatively. The ≥6-mm acromiohumeral distance (AHD) subgroup had a larger decrease in humeral head superior translation from preoperatively than did the <6-mm AHD subgroup (6 months: P = .026; 1 year: P = .032). The retear group had significantly greater humeral head superior translation at 1 year postoperatively than did the ≥6-mm and <6-mm AHD subgroups (post hoc test: P < .001; ≥6-mm AHD vs retear group: P = .001; <6-mm AHD vs retear group: P = .012). Conclusion: SCR with intact grafts resulted in decreased humeral head superior translation after 6 months. Patients with retears showed no improvement in humeral head superior translation. Patients with a preoperative AHD <6 mm had less improvement in humeral head superior translation than did those with a preoperative AHD ≥6 mm. Early surgical treatment before an excessive decrease in preoperative AHD could be helpful for postoperative humeral head translation recovery.

Arthroscopic Superior Capsular Reconstruction for Massive Irreparable Rotator Cuff Tears Results in Significant Improvements in Patient Reported Outcomes and Range of Motion: A Systematic Review

“…Lee et al. 50 demonstrated that humeral head superior translation was detected between 6 months and 12 months after ASCR for MIRCTs. As such, the authors speculate that AHD may decrease over time postoperatively.…”

“…A recent study 49 reported that AHD had increased 2.2 mm postoperatively at 1year follow up, which was significantly higher than in a current study (mean improvement of AHD: 2.2 versus 1.7 mm, P < .05). Lee et al 50 demonstrated that humeral head superior translation was detected between 6 months and 12 months after ASCR for MIRCTs. As such, the authors speculate that AHD may decrease over time postoperatively.…”

Effect of Anterior Acromial Coverage on Functional and Radiological Outcomes After Arthroscopic Repair of Anteroposterior Massive Rotator Cuff Tears

“…Generally, in vivo glenohumeral kinematics is evaluated using biplane fluoroscopy, and superoinferior and AP translations of the humeral head during the entire process of arm elevation are measured; increased humeral head translation usually indicates shoulder dysfunction or treatment failure. 24,41 However, it is difficult to apply this reliable technique as a conventional examination for patients with RCTs because of radiation concerns and time-consuming analyses. Some researchers have introduced simplified methods of measuring PHM and GHA in the scapular plane using single-plane fluoroscopy or radiography at different stages of active scaption.…”

“…Recently, a case-control study demonstrated that MRCTs with captured fulcrums had larger anterior acromial coverage (AAC), 9 thus leading to improved glenohumeral kinematics such as greater shoulder abduction. 6 Given the significant superior translation of the humeral head in AP-MRCTs and the different types of mechanical fulcrums for shoulder abduction, 6,17,41 AAC may be a prognostic factor of rotator cuff repair in terms of glenohumeral kinematics, tendon integrity, and patient-reported outcomes.…”

The Number of Surgeons Using Superior Capsular Reconstruction for Rotator Cuff Repair Is Declining

“… 18 The key difference of IG compared with SCR is that IG attempts to provide a structural graft and fill in a defect between the dynamic residual tendon and the bone interface, whereas SCR is fixed from the glenoid to the tuberosity and aims to restore joint kinematics and stability. 15 , 19 Clinical results in RCR have been variable with these biologic products, although there have been some early favorable reports with lower levels of evidence. 20 , 21 , 22 There is basic science and early clinical reports to support SCR and biologic augmentation.…”