Top 10 Tips for the Humeral Technique in TSA
Total shoulder arthroplasty (TSA) is commonly performed to treat severe pain and stiffness resulting from arthritis or degeneration of the shoulder joint. A predictable, successful outcome requires good surgical technique, including glenoid exposure and balancing of the soft tissues.
Richard J. Friedman, MD, FRCSC, from the Medical University of South Carolina shared his top 10 tips for the humeral technique in TSA at ICJR’s annual Shoulder Course in Las Vegas:
1. For complete capsular release from the humeral neck, start anteriorly, move medially, and finally externally rotate to obtain posterior release. Posterior release is especially important for ensuring good exposure, Dr. Friedman said. Protect the axillary nerve from damage during this step.
2. All humeral osteophytes, whether anterior, medial, or posterior, should be removed with a rongeur and osteotome either before or after humeral osteotomy.
3. When performing a humeral head osteotomy, match the inclination with the prosthesis to ensure a 30° retroversion. After visualizing the sulcus medially to the greater tuberosity to determine the correct height, make the cut along the anatomic neck. Cutting at less than this height increases the risk of cutting into the greater tuberosity and damaging the rotator cuff; cutting higher leaves too much bone and makes the joint too tight. A correct cut will usually involve removing less bone than anticipated.
4. The humeral reaming step involves extending and adducting the humerus. Dr. Friedman recommends starting off-center in the superlateral part of the proximal humerus. Reaming should be performed with tapered tips until “cortical chatter” occurs, indicating initial contact of the reamer with cortical bone. Use a gentle technique that avoids torque.
5. When broaching, the arm should be supported under the elbow to keep the lateral fin 5 mm to 9 mm posterior to the bicipital groove. Broaching should start one to two sizes down from the last ream. Avoiding rotation and varus is crucial for maintaining press fit fixation. The broach is fully seated when the pitch changes from a high-pitched, banging sound to a deeper tone. At this point, press fit fixation and stability can be assessed. If using a calcar planar, it should be turned on before contacting bone.
6. During trial reduction, the humeral head should be positioned 5 mm to 9 mm above the greater tuberosity, keeping in mind the “Goldilocks” rule for a fit that is not too tight and not too loose. Dr. Friedman recommends assessing tension in the cuff, deltoid, and subscapularis muscles, as well as in the tuberosity-glenoid space (shuck test). To ensure proper tension and stability in the soft tissues, a humeral head of the appropriate thickness should be used, posterior and inferior subluxation should not exceed 50%, external rotation should be enabled without anterior displacement, and cross-body adduction should be possible without instability.
7. Either a concentric or eccentric humeral head may be selected. The size of the humeral head should provide coverage of the proximal humerus but avoid overhang in any direction, which can damage the cuff. The bone and implant should then be properly aligned relative to each other.
8. If an uncemented humeral stem is used, ensure that it is slightly larger than the last broach used for the interference fit. Dr. Friedman’s tip is to gently but firmly impact the humeral stem while avoiding pulsatile lavage and maintaining correct varus-valgus alignment.
9. If a cemented humeral stem is used, downsize the stem from the last broach to ensure an adequate cement mantle. The cement restrictor should be tapped 1 cm past the tip of the humeral stem. After brushing, irrigating, and drying the canal, the cement is injected in a retrograde manner. The humeral stem should be fully seated and held still until the cement sets.
10. During subscapularis repair, Dr. Friedman recommends using multiple non-absorbable sutures. If medializing the insertion, the sutures should be inserted through the bone before the stem is implanted. External rotation should be at least 30° without tension. Finally, the rotator interval is closed.