Dermal Allograft Superior Capsule Reconstruction Biomechanics and Kinematics.
- 2021
Available online from MWHC library: 1995 - present, Available in print through MWHC library:2004 - 2007
CONCLUSIONS: In an irreparable supraspinatus tear model, the dermal allograft SCR showed competency in stabilizing the glenohumeral joint, decreasing glenohumeral and subacromial contact pressures, and increasing the acromion-humeral distance. LEVEL OF EVIDENCE: Basic Science Study; Biomechanics. Copyright (c) 2021. Published by Elsevier Inc. METHODS: This controlled laboratory study tested eight fresh-frozen cadaveric shoulders using a custom test frame. Balanced loading configuration centered the humeral head on the glenoid, and unbalanced load created a force pulling the head towards the acromion. Experimental conditions included the intact rotator cuff, irreparable supraspinatus tear (ISST), and dermal allograft SCR. A digital sensor measured glenohumeral and subacromial contact pressure maps, and a microscribe measured acromion-humeral distance. PURPOSE: To investigate the effect of a dermal allograft SCR on kinematics and joint pressure biomechanics immediately after simulated superior irreparable rotator cuff tear. RESULTS: Glenohumeral contact pressure of ISST was 175% (295+/-44 kPa; P=0.018) of the intact rotator cuff value (169+/-10 kPa) at 0 in the balanced condition and 176% (P=0.048) of intact at 30. SCR decreased glenohumeral contact pressure to 110% (185+/-27 kPa; P=0.044) of intact at 0 and to 95% (P=0.034) at 30. Unbalanced ISST contact pressure was 146% (365+/-23 kPa; P=0.009) of intact (250+/-24 kPa) at 0 and 122% (P=0.045) at 60. SCR decreased contact pressures to 110% (274+/-21 kPa; P=0.039) of intact at 0 and to 89% (P=0.003) at 60. ISST increased superior migration of the humeral head, decreasing the acromion-humeral distance by 3.0+/-0.6 mm (P=0.006) in the unbalanced condition at 0. SCR increased the acromion-humeral distance to a value similar to that of the intact cuff (P=0.003). SCR significantly lowered subacromial pressures in the unbalanced condition.