Thursday, June 8, 2017

Total shoulder: lesser tuberosity osteotomy or subscapularis tenotomy

Subscapularis Tenotomy Versus Lesser Tuberosity Osteotomy for Total Shoulder Arthroplasty: A Systematic Review 

Subscapularis tenotomy (ST) has been the standard method of mobilizing the subscapularis during the approach to a total shoulder arthroplasty (TSA). Recently, lesser tuberosity osteotomy (LTO) has gained in popularity. These authors performed a systematic review to elucidate any differences in clinical or radiographic outcomes between ST and LTO. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we identified clinical and/or radiographic TSA studies with minimum mean 2-year follow-up and level I to IV evidence. Twenty studies (1420 shoulders, 1392 patients) were included in the study. The ST group had significantly more patients with osteoarthritis (P = .03) and fewer patients with posttraumatic arthritis (P = .04). At final follow-up, mean (SD) forward elevation improvements were significantly (P < .01) larger for the ST group, +50.9° (17.5°) than for the LTO group, +31.3° (0.9°). Complication rates were almost identical, but the ST group showed a trend (P = .31) toward fewer revisions (10.0% vs 16.2%). There were no differences in Constant scores, pain scores, or radiolucencies.

Comment: We avoid lesser tuberosity osteotomy because (1)  it can weaken the metaphysics, compromising press fit fixation of the humeral component in the metaphysis, (2) it obligates sacrifice of the long head tendon of the biceps, which is an important contributor to shoulder stability, and (3) it can lead to troublesome non union of the osteotomized fragment.

Our surgical approach involves a careful peel of the subscapularis tendon from the lesser tuberosity with attention to preserving the integrity of the biceps tendon and a 360 degree release of the capsule from the glenoid to resolve limitation of external rotation. By retaining the capsule on the deep surface of the tendon, the strength of the repair is enhanced.

At the conclusion of the case, drill holes are placed through good bone at the margin of the neck cut and six sutures of #2 non-absorbable suture are passed through these holes.

 These sutures are then passed through the tendon edge and tied securely.

A principal cause of post operative subscapularis failure is the overzealous and premature stretching of external rotation or premature initiation of internal rotation strengthening as explained in this post:
Rehabilitation after shoulder arthroplasty - cautions!

Our approach is to limit external rotation stretching to zero degrees (the hand shake position) and avoid internal rotation strengthening exercises for at least 3 months after surgery. We also caution patients about the risk of events that may suddenly externally rotate the shoulder such as a fall or a sudden pull on the arm from a leashed dog.

The interested reader will want to read the related posts below:

Subscapularis failure after arthroplasty - evaluation and management

The biomechanics of subscapularis repair - all sutures are not equal!

Subscapularis in shoulder arthroplasty

Shoulder joint replacement arthroplasty - spare the subscapularis, spoil the arthroplasty?

How well does the subscapularis work after total shoulder arthroplasty? ?Hazards of inter scalene block?

Failure of lesser tuberosity osteotomy in total shoulder joint replacement - a cautionary tale

Is lesser tuberosity osteotomy a benign approach to shoulder arthroplasty?
Shoulder joint replacement arthroplasty - lesser tuberosity osteotomy, are there data in support of it?