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    Total Shoulder Arthroplasty with a Glenoid Augment

    A 69-year-old male patient with chronic left shoulder pain had been “just trying to live with it,” but now the pain and impaired motion are interfering with his job as truck driver.

    Authors

    Cory Lebowitz, DO, and Luke S. Austin, MD

    Case Presentation

    A 69-year-old right-hand-dominant male patient who works as a truck driver presents with chronic left shoulder pain accompanied by a feeling of “grinding” in the shoulder and decreased range of motion. He was diagnosed with osteoarathritis in 2014. He has a history of primary hypertension, obstructive sleep apnea, and prostate cancer.

    The patient denies any specific trauma or prior injuries to his shoulder. He reports that over the course of 3 or 4 years, he has tried non-steroidal anti-inflammatory drugs, corticosteroid injections, and activity modification to mange the pain. He had been “just trying to live it,” but now he is seeking surgical management due to the constant pain and his inability to drive his truck.

    Physical Examination

    • Positive glenohumeral crepitus
    • Pain with passive and active range of motion at terminal end points
    • Passive forward flexion 90, external rotation 5
    • Deltoid motor function intact, with full strength distally in the left upper extremity
    • Axillary, median, musculocutaneous, radial, and ulnar nerve sensation intact to light touch
    • Palpable brachial, radial, and ulnar pulses

    Differential Diagnosis

    • Glenohumeral degenerative joint disease
    • Glenohumeral post-traumatic arthritis
    • Adhesive capsulitis

    Imaging

    Radiographs were ordered, including an anteroposterior internal rotation view, anteroposterior external rotation view, and axillary view of the left shoulder (Figure 1). Degenerative joint disease was seen throughout the glenohumeral joint,with posterior glenoid bone loss with posterior subluxation seen on axillary view. To better assess the posterior subluxation and glenoid bone loss, a computed tomography (CT) with 3-dimensional (3D) reconstruction was ordered (Figure 2).

    Figure 1. Radiographs show glenohumeral joint degenerative joint disease with glenoid bone loss and posterior subluxation of the humeral head

    Figure 2. The CT scans show glenohumeral joint degenerative joint disease with a retroverted glenoid and confirms glenoid bone loss and humeral head posterior subluxation.

    Diagnosis

    • Left glenohumeral degenerative joint disease with glenoid bone loss (Walch B2)

    Walch et al [1] examined 2-dimensional CT scans of glenoid morphology in primary glenohumeral osteoarthritis and developed a classification system with 3 grades and several subgroups:

    • A1: Glenoid with minimal erosion and a centered humeral head
    • A2: Glenoid with major central erosion with centered humeral head
    • B1: No bony erosion to the glenoid with a posterior subluxated head
    • B2: Posterior erosion with biconcavity of the glenoid and a posterior subluxated head
    • C: Dysplastic glenoid with at least 25° of retroversion regardless of glenoid erosion

    Modified classifications have since been introduced, adding B3 and D. [2]

    For more information on B2 glenoids and their surgical management, please refer to an article previously published on ICJR.net, Management of the B2 Glenoid with Anatomic TSA: Ream, Step, or Wedge? by Ho et al. [3]

    Surgical Treatment Option

    The authors recommended a left total shoulder arthroplasty with an augmented glenoid for:

    • Pain control
    • Restoration of premorbid anatomy (version, inclination, subluxation)
    • Restoration of function, motion, and strength
    • Return to functional activity level

    After the benefits and potential surgical and implant-related risks were explained to the patient, he agreed to the total shoulder arthroplasty. The type of implant to be used during the procedure was a 25 augmented glenoid (PerFORM+; Wright Medical Group, Memphis, Tennessee), a 52×19 high-offset head, and a 4B standard stem (Flex; Wright Medical Group, Memphis, Tennessee; Figure 8). Advantages of this implant include the following:

    • Technically less demanding than using a bone graft
    • Augment allows for decreased reaming/medialization, which maintains cortical bone and increases the stability of the implant
    • Unlike a bone graft, the augment does not rely on union

    A drawback of using glenoid augments, however, is the scarcity of long-term outcome studies.

    Preoperative Planning

    A 3D software system (Tornier BLUEPRINT 3D Planning; Wright Medical Group, Memphis, Tennessee) was used to customize the implant size and visualize the position specific to the glenoid, humerus, and joint based on the 3D CT scan:

    • Preoperative glenohumeral anatomy. The software calculates the patient’s glenoid retroversion, inclination, best fit radius, and posterior subluxation (Figure 3).
    • Glenoid and humerus planning. The glenoid is prepared in all planes to adequately seat the glenoid (>80%) (Figure 4). This is done through adjustments in the version, inclination, lateralizination, size, and augment. The reaming axis is configured after the appropriate glenoid size has been determined (Figure 5). Next, the humerus is planned for an appropriate-size head and stem (Figure 6).
    • Joint planning. After the glenoid and humerus have been sized, the software displays the correction of the version and inclination (Figure 7).

    Figure 3. Preoperatively, the glenoid is 21 retroverted with 4 of superior inclination. The humerus is 83% posterior sublimated.

    Figure 4. Glenoid planning: Sizing of the glenoid includes changing the inclination, overall size (small, medium, or large), radius, and augment (15, 25, or 35), version, and lateralization, with a goal of greater than 80% seating.

    Figure 5. Reaming axis guide for the glenoid.

    Figure 6. Humerus planning: The appropriate head and stem are chosen.

    Figure 7. Joint planning: After the glenoid, head, and stem are sized, the joint is mapped out.

    Procedure

    • The patient was placed in the beach chair position, with his left arm draped free. He received an interscalene block with general anesthesia.
    • A deltopectoral approach was used to expose the glenoid and proximal humerus, which included a long-head of the proximal biceps tenodesis to the pectoralis major tendon and lesser tuberosity osteotomy. The anterior capsular was excised. Glenoid retroversion with posterior wear was observed intraoperatively.
    • The glenoid was sized by aligning the center of glenoid profile with the subscapularis fossa using the Fossa Referencing Guide and placing the centering K-wire to correct the glenoid version and inclination deformity. The anterior glenoid was then reamed (Figure 8). Due to cost considerations, the Fossa Referencing Guide was used instead of a patient-specific guide.

    Figure 8. Introperative images showe the native glenoid with the Fossa Referencing guide to appropriately seat the guide pin and proceed with anterior glenoid reaming.

    • A wedge glenoid was trialed to find the appropriate size. A small guide hole was then drilled into the glenoid to properly fit a specialized reamer to create a 25 posterior wedge (Figure 9).

    Figure 9. Intraoperative images show the use of posterior reamer to further correct the glenoid retroversion and posterior wear.

    • A center hole over the K-wire was drilled using the guide, followed by 3 peripheral holes (Figure 10).

    Figure 10. Intraoperative images show the glenoid holes drilled appropriately to seat the trial.

    • The glenoid trial fit flush on the glenoid surface and also corrected the version and inclination deformity. This was the same trial size that was indicated by the preoperative planning system (Figure 11).

    Figure 11. Intraoperative images show the prepared glenoid and its A25 augment trial.

    • Bone from the humeral head was used to graft the central hole. The glenoid component was placed using cement.
    • The humerus was then prepared, broached, sized, and trialed appropriately. Minor changes were made from preoperative blueprint planning. Preoperatively, we had planned to use a 52 x 19 high-offset head and 4B stem, but after trialing the components, we ended up using a 52 x 23 low-offset head with a 5B stem.
    • The final humeral implant was press-fit into place, the shoulder was reduced, and stability was confirmed.
    • The shoulder was copiously irrigated with antibiotic saline.
    • The lesser tuberosity osteotomy was then repaired.
    • The deltopectoral interval was closed, followed by the skin, and then the incision was covered with a sterile dressing.

    Postoperative Course

    The patient tolerated the procedure well without any complications. Postoperative radiographs of the anteroposterior shoulder taken in the PACU can be seen in Figure 12.

    Figure 12. Postoperative radiographs of the left shoulder 6 weeks after anatomic total shoulder replacement with augmented glenoid. The humerus is well seated in the center of the glenoid without subluxation.

    The patient was made non-weight-bearing in a sling following the procedure and was started on 81 mg of aspirin daily for deep vein thrombosis prophylaxis. He began a passive range-of-motion protocol on POD1 and was then discharged home.

    On POD14, the patient returned to our office for a follow-up visit. He was doing well, without any numbness, tingling, fevers, or chills. He did not have any drainage from the incision. His Visual Analogue Scale (VAS) pain score was 0 mm. He could hold his arm for belly press testing against gravity, and he had passive forward elevation to 130 and external rotation to 30.

    By 6 weeks postoperative, the patient had 150 of forward elevation, to L1 internal rotation, and 35 of external rotation. His VAS pain score was 10 mm. The ASES score at 6 weeks was 86, however, 4 categories could not be assessed secondary to postoperative restrictions.

    Author Information

    Cory Lebowitz, DO, is an orthopaedic surgery resident at Rowan University School of Osteopathic Medicine, Stratford, New Jersey. Luke S. Austin, MD, is a board-certified orthopaedic surgeon specializing in shoulder and elbow management at The Rothman Institute, Philadelphia, Pennsylvania. He is an associate professor of orthopaedic surgery at Thomas Jefferson University Hospital in Philadelphia.

    Disclosures

    Dr. Lebowitz has no disclosures relevant to this article. Dr. Austin has disclosed that he receives research funding from Zimmer Biomet.

    Shoulder and Elbow Section Editor, Rothman Institute Grand Rounds

    Luke S. Austin, MD

    References

    1. Walch G, Badet R, Boulahia A, Khoury A. Morphologic study of the glenoid in primary glenohumeral osteoarthritis. J Arthroplasty 1999;14:756-60.
    2. Bercik, Michael J., et al. “A modification to the Walch classification of the glenoid in primary glenohumeral osteoarthritis using three-Dimensional imaging.” Journal of Shoulder and Elbow Surgery, vol. 25, no. 10, 2016, pp. 1601–1606
    3. Ho, Jason C, et al. “Management of the B2 Glenoid with Anatomic TSA: Ream, Step, or Wedge.” International Congress for Joint Reconstruction, 16 Jan. 2018, https://icjr.net/articles/management-of-the-b2-glenoid-with-anatomic-tsa-ream-step-or-wedge.