rTSA With Humeral Head Autograft Glenoid Reconstruction

Abstract

Background:

Untreated chronic massive rotator cuff tears and primary osteoarthritis can lead to conditions of significant retroversion, posterior bone loss, and humeral head subluxation.

Indications:

Reverse total shoulder arthroplasty with humeral head autograft glenoid reconstruction may be indicated in patients with advanced glenohumeral osteoarthritis and/or severe glenoid retroversion/bone loss due to rotator cuff arthropathy, trauma, primary, or inflammatory osteoarthritis.

Technique:

Besides routine radiography and preoperative computed tomography (CT) scans, 3-dimensional (3D) planning software is often performed as a routine part of preoperative planning. A 3D printed model of the glenoid can also be helpful in cases of significant bone deformity. Patients are placed in a 45° modified beach chair position. Using a standard deltopectoral approach, the glenoid is exposed. An anatomic humeral head resection is made. The contour of the articular margin of the humeral head should match the glenoid bone deficiency anatomically as it has been chronically resting within the glenoid defect. Three dimensional preoperative planning and the 3D printed model are used to make an asymmetric humeral head autograft which should match the deficiency perfectly. The articular cartilage is removed with a burr. The graft and baseplate are coupled together (metaphyseal bone facing the baseplate and prepared articular side of the graft facing native bone) and measurements are performed with the preoperative planning software to fashion a graft with the appropriate dimension and with the desired amount of lateralization. The bone graft is then compressed with the baseplate to the native glenoid and fixed with screws.

Results:

In select patients with careful preoperative planning, excellent outcomes can be achieved with careful gradual resumption of range of motion and strength with physical therapy. Sequential radiographic imaging is performed up to 6 months and beyond to confirm solid union of graft to native glenoid bone and incorporation into the baseplate.

Discussion/Conclusion:

Reverse total shoulder arthroplasty (rTSA) with humeral head autograft glenoid reconstruction is an excellent option to address severe glenoid bone loss and restore the native joint line for both primary osteoarthritis and rotator cuff arthropathy. Using 3D CT scans, 3D preoperative planning software and 3D printing of the glenoid can help achieve a good outcome.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

This video demonstrates our technique for humeral head autograft before reverse total shoulder arthroplasty (rTSA) in a patient with severe glenohumeral osteoarthritis (OA) and severe glenoid deformity.

Here are our author disclosures.

Here is an outline of the presentation topics we will discuss in this video.

Glenohumeral osteoarthritis with severe glenoid bone loss can occur due to rotator cuff arthropathy, primary or inflammatory osteoarthritis, and trauma. In addition, given its association with glenoid loosening, severe glenoid erosion often contributes to worse outcome.

In this presentation, we will discuss rotator cuff arthropathy with severe glenoid bone loss. History and physical examination are the first steps in evaluating these patients which often indicates shoulder pain, with or without diminished range of motion.

Imaging includes a true anteroposterior (AP) view (Grashey view) and lateral axillary view. The Grashey view is used to determine Hamada classification.

A computed tomography (CT) scan is important for preoperative planning. Axial and coronal imaging provides a better understanding of inclination and version. The Walch classification is often used to describe glenoid wear for primary osteoarthritis. An A glenoid specifies central erosion with a concentric humeral head as grade A, a B glenoid is defined as a posterior subluxed humeral head, a C glenoid is a dysplastic glenoid with greater than 25° retroversion, and a D glenoid specifies anteversion or anterior subluxation.

A 3-dimensional (3D) reconstruction of the CT scan with preoperative planning software provides a more accurate assessment of anatomic parameters and allows for virtual and optimal placement of the glenoid component especially if combined with a patient specific guide particularly for server glenoid deformity. A 3D printed model of the glenoid may allow real-time understanding of the glenoid bony defect and help with intraoperative preparation of a humeral head autograft.

Operative treatment to address glenoid bone deficiency consists of 3 different options. The first option is eccentric reaming. In this technique, the native glenoid is reamed to correct version. This technique creates a matched surface for glenoid baseline at the expense of removing glenoid bone and potential medialization of the joint line. This technique may be inappropriate for severe glenoid retroversion due to the loss of glenoid bone vault and potential excessive removal of subchondral bone and is generally used for less severe deficiency such as glenoid retroversion ≤ 15^o.

A second technique for addressing glenoid bone defect is with use of an augmented glenoid baseplate. Augments are typically either full or half-wedged. This technique may be indicated if glenoid retroversion is > 15° to 20° or baseplate contact with a standard implant with native bone is <50% after appropriate ream correction. This technique preserves subchondral bone and can minimize ream preparation. There remains, however, a lack of long-term outcomes. In addition, augments may still not be able to address severe glenoid bone loss.

The third option to address glenoid bone defect is bone grafting, which may be indicated in severe glenoid bone deficiency or when deficiency is too great even for an augmented baseplate. The graft is fashioned to the glenoid bone deficiency and intended to restore glenoid version and volume, while maximizing graft to native bone contact. An additional advantage cited by Hussain et al⁴ is the lack of donor site morbidity when using a humeral head autograft source. However, this procedure may be technically demanding. Our personal experience with this technique reflects results reported in the literature from Tashjian et al⁵ and Boileau et al² demonstrating bone graft incorporation rates of 93% to 94%. Tashjian et al⁵ has also reported rates of 100% incorporation for large defects. Our indications for bone grafting are in severe deficiencies when off the shelf augments cannot accommodate the deformity. Our experiences are similar to Tashjian et al⁵ with 100% incorporation of the bone graft.

Our patient is a 70-year-old woman, right-hand dominant, with chronic right shoulder pain which has been worsening over the last few months. She is unable to perform activities of daily living (ADLs) comfortably and has failed conservative management including physical therapy (PT), injections, and activity modification. Her past surgical history is relevant for an open rotator cuff repair 17 years ago. On physical examination, she has well preserved range of motion (ROM), with 4/5 strength in forward flexion (FF) and external rotation (ER) and 5/5 strength in internal rotation (IR).

Her x-ray show grade 4 Hamada changes with primarily superior glenoid wear and osteophyte formation and evidence of previous rotator cuff repair. A CT scan was performed to get a better understanding of her deformity and glenoid wear pattern.

We further assessed her CT scan using 3D preoperative planning software. On the coronal view, we can get a better appreciation of her large superior glenoid wear pattern and on the axial view, we can see the decreased glenoid vault volume. Using preoperative planning software, we did not feel that her deformity was amendable to ream correction or an augmented baseplate.

We will now transition to the video demonstration of the procedure.

For our surgical technique, we made a standard deltopectoral approach for glenoid exposure. We generally perform a standard humeral anatomic neck cut. However, the preoperative planning software can assist by determining the amount of lateralization required through the bone graft. This measurement will allow the surgeon to predetermine the largest dimension of the graft and the humeral head resection can be made accordingly.

With bone grafting, we routinely use a sterilizable 3D printing model of the glenoid using the Arthrex (Naples, FL) VIP planning system, allowing the surgeon to determine the portion of the bone graft or humeral head resection that articulates the defect intraoperatively, in addition to a patient specific guide for the central guide pin. The model has a hole created for the planned patient-specific central guide pin, and this aids in the ability to create an asymmetric bone graft, as illustrated in the video. In addition, a large 35 mm post is also available in the system, allowing flexibility of bone graft size to ensure 15 mm of the baseplate post is within the native glenoid vault. We then put the humeral head on the glenoid model with the articular side down. Since these have been articulating, they should match the contour perfectly and will help us better assess what portion of humeral head should be taken for the best fit contour of the graft. The humeral head bone graft is held in place while a guide pin is placed in antegrade fashion though the plane guide pin hole in the model. The humeral head is then placed on a tray lid with holes with articular side facing up and held in place with 2 towel clips. The female reamer is then placed over the pin to ensure that we will obtain a 360° graft and not violate one edge of the humeral head. We then ream over the pin to obtain our graft. After creating the bone graft, the articular portion of the graft is burred to the subchondral bone, and a 1.1 mm drill bit is used to penetrate holes for vascular channels. These 2 steps are necessary to create a bleeding surface and aid in bone graft incorporation. Once the bone graft is fully prepared, the flat side should sit against the baseplate, and the asymmetric articular side of the graft should be placed against the native glenoid.

Then humeral head graft is placed over the pin in the model. Ensure that the deformity has corrected, and the graft sits flush on the glenoid. A burr may have to be used to smooth out any irregularities and improve overall contact with the graft and the glenoid. We also make a mark at the 12 o’clock position on the graft to better judge the rotation during implantation. The graft is then placed on the inserter with the baseplate.

The patient’s specific guide is then placed over the guide pin on the model to assess how it should sit on the glenoid. The guide is then placed on the patient’s glenoid to confirm that it matches the preoperative plan. We then ream over the guide pin for our central post.

A lateralized baseplate is unnecessary as the bone graft can achieve the desired lateralization. We measure the graft and baseplate together so that we make sure this will not over lateralize the construct based on the preoperative CT scan. The graft and baseplate are then impacted in together. At least 15 mm of post should be within the glenoid vault to obtain appropriate fixation. In general, we aim for approximately 1 to -2 mm of lateralization on the high side of the glenoid defect, with an asymmetric bone graft accommodating the low side. However, the dimension of the bone graft can be adjusted accordingly based on the amount of lateralization desired, provided that 15 mm of post is within the native glenoid vault. We then confirm that we are fully seated circumferentially. We then place our 4 peripheral screws. The drill depth can be compared with the preoperatively planned screw length as one more check to make sure that we likely have good placement of the components and deformity correction.

Here is our final bone graft and baseplate construct. The glenosphere is then attached and humerus is prepared in standard fashion. Both inlay and onlay humeral components can be used with bone grafting on the glenoid. However, the authors prefer an inlay component with bone grafting, as we typically perform bone grafts when glenoid deformities are severe. These pathologies are associated with significantly medialized joint lines and glenohumeral joint stiffness. In these situations, a bone graft will by nature, lateralize the joint line greater than the preoperative pathologic glenoid, and an inlay humeral component allows greater ease of reduction of the joint in a stiff shoulder.

A standard postoperative protocol is followed. Postoperatively, the patient was placed in sling for 6 weeks with elbow ROM exercises at the first postoperative visit to allow for bone incorporation and healing. Physical therapy with active and passive ROM was initiated at 6 weeks. Strengthening began at 12 weeks. Routine x-rays are obtained to assess for bone graft incorporation and any concerns with osteolysis or loosening.

At 1 year, radiographs demonstrate full incorporation of the bone graft with an overall successful postoperative outcome.

The Visual Analog Scale VAS (VAS) score was 0/10, FF ROM 140°, ER 30°, and IR to L4. Strength was 4/5 in all directions, and Subjective Shoulder Value (SSV) was 85%. Currently, this patient is more than 2 years from surgery without failure of the bone graft, loosening, or significant osteolysis.

Please pause the video to review some pearls and pitfalls with this technique. Please see below for our presentation references. Thank you for viewing our video.