Ultrasound assessment after a subscapularis-sparing approach to total shoulder arthroplasty.

BACKGROUND: Although anatomic total shoulder arthroplasty (ATSA) has favorable outcomes, nearly all techniques involve subscapularis tendon release for shoulder joint access. Such takedown of the subscapularis may be associated with decreased function, instability, and pain. Subscapularis-sparing approaches have the theoretical benefits of improved function, decreased failure of the tendon reattachment site, and early range of motion and rehabilitation. The primary purpose of this study was to use ultrasound to assess the postoperative integrity of the subscapularis tendon and surrounding soft tissues after ATSA with a subscapularis-sparing technique through an extensile anterosuperior skin incision. Our hypothesis was that this subscapularis-sparing approach would have low rates of subscapularis disruption. METHODS: A consecutive cohort of patients who underwent subscapularis-sparing ATSA between 2014 and 2017 were included. Ultrasound was used to evaluate the rotator cuff tendons and deltoid postoperatively, and these were classified as intact, disrupted, or unable to be adequately visualized. Clinical outcome scores, range of motion, and strength measurements were also collected at 1-3 years postoperatively. RESULTS: Thirty-seven subscapularis tendons and 40 supraspinatus and infraspinatus muscles were adequately visualized and included for analysis. Of the subscapularis muscles, 32 (86%) were intact; 38 of the visualized supraspinatus muscles (95%) and 39 of the infraspinatus muscles (98%) were intact. No dehiscence or loss of integrity of the deltoid was noted. Clinical comparison between patients with disrupted subscapularis muscles and patients without such disruption demonstrated no difference in clinical outcome scores and postoperative range of motion but showed less strength in forward flexion, abduction, and external rotation. CONCLUSIONS: The rate of subscapularis disruption using a subscapularis-sparing approach for ATSA was low (14%), but the potential for tendon disruption was not eradicated. Favorable clinical outcomes support this surgical approach as a potential technique for ATSA.

Subscapularis sparing total shoulder arthroplasty through a superolateral approach: a radiographic study.

BACKGROUND: Most anatomic total shoulder arthroplasty (ATSA) techniques release and reattach the subscapularis tendon. The risk of failed healing is a widely recognized complication. The purpose of this study was to radiographically compare a traditional deltopectoral (DP) approach and a superolateral subscapularis sparing (SSS) technique through the rotator interval. METHODS: A single, independent, blinded, reviewer analyzed preoperative and postoperative radiographs of patients undergoing ATSA performed by a single surgeon. The reviewer assessed humeral head height, humeral head medial offset, humeral head diameter, head-neck angle, humeral head centering, and coracohumeral offset, and used the anatomic reconstruction index (ARI) to evaluate overall reconstruction quality. RESULTS: There were 70 SSS and 20 DP patients included. When comparing preoperative with postoperative differences, we found that there was no difference between groups in humeral head height (P = .19), humeral head medial offset (P = .38), and coracohumeral offset (P = .07). The DP group had a mean humeral head diameter oversizing of 1.4 mm, whereas the superolateral group had an undersizing of 2.8 mm (P < .001). The head-neck angle difference of the SSS approach was 2° greater than that found with the DP group (P < .001). The humeral head centering in the DP group was 7% displaced vs. 12% with the SSS group (P = .001) relative to the glenoid size. The ARI was 7.35 for the DP group and 6.93 for the SSS group (P = .50). DISCUSSION AND CONCLUSIONS: Radiographic comparison of these 2 ATSA techniques identified no statistical significant difference in 4 of 7 radiographic measurements and ARI. The SSS ATSA is a reasonable approach that yields similar radiographic measurements as a traditional DP total shoulder arthroplasty approach.

Subscapularis-Sparing Rotator Interval Approach for Anatomic Total Shoulder Arthroplasty.

BACKGROUND: A subscapularis-sparing approach to anatomic total shoulder arthroplasty (TSA) is used for patients with glenohumeral osteoarthritis who have an intact rotator cuff and sufficient bone volume. DESCRIPTION: A 7 to 10-cm anterosuperior incision is made with the patient in the beach chair position. The anterolateral deltoid muscle raphe is split, and the shoulder is externally rotated to bring the rotator interval to the field. A flap of interval tissue is incised, tenodesis of the biceps tendon is performed, and the interval tissue is incised straight back to the glenoid from the upper edge of the subscapularis, creating a triangular piece of tissue referred to as a "trapdoor." Two Darrach retractors are placed to expose the humeral head. An intramedullary guide is placed, and a humeral head osteotomy is performed. The glenoid is exposed, and the glenoid component is placed after sizing, preparation, drilling, and insertion of trial components per the surgical technique. The humeral head size is estimated by measuring, and the humeral stem size is decided by sequentially inserting the trial components. The permanent humeral stem is inserted, and the permanent humeral head is implanted after insertion of trial components. The trapdoor is sutured, the deltoid is reattached, and subcutaneous tissue and skin are sutured. ALTERNATIVES: The traditional surgical approach for anatomic TSA involves release and reattachment of the subscapularis tendon. RATIONALE: Nearly all anatomic TSA techniques require the subscapularis to be released, with a peel, tenotomy, or osteotomy, and then repaired on completion of the arthroplasty. Failure of the subscapularis to heal is an unfortunate and potentially devastating complication following anatomic TSA that has been linked to decreased function, instability, and pain1-4. Subscapularis dysfunction following anatomic TSA is seen in one-third to two-thirds of patients, with evidence of complete tears in up to 50% of asymptomatic patients using ultrasound examinations1-5.Sling immobilization with avoidance of excessive passive external rotation and active internal rotation is recommended to help prevent postoperative rupture of the subscapularis repair6-8. However, postoperative motion restrictions to protect the subscapularis may lead to stiffness and may negatively impact function and satisfaction.We describe a subscapularis-sparing TSA, in which we address and improve on 3 technical difficulties identified by Lafosse et al.9: (1) difficulty ensuring an anatomic humeral neck cut because of the difficulty visualizing the anterior aspect of the shoulder, (2) inadequate resection of inferior humeral neck osteophytes, and (3) undersizing of the humeral head.