Complex Revision Glenoid Reconstruction with Use of a Distal Tibial Allograft.

BACKGROUND

Coracoid transfer procedures have been increasingly utilized for anterior shoulder instability with associated glenoid bone loss. Unfortunately, in a young, high-risk patient population, these procedures can fail secondary to traumatic causes but also because of bone graft resorption or malposition or hardware prominence, among other reasons. In active patients, revision glenoid reconstruction may be indicated. Distal tibial osteoarticular allografts have been utilized to treat recurrent anterior shoulder instability for several years. Recently, this technique has been applied to cases of failed Latarjet procedures in order to reconstitute the absent glenoid bone stock, demonstrating excellent clinical outcomes at a minimum follow-up of 3 years.

DESCRIPTION

The procedure is performed in the beach-chair position. First, a diagnostic shoulder arthroscopy is performed to assess the cartilaginous surfaces, to examine the Hill-Sachs lesion and its engagement, and to remove any loose bodies. Next, the prior deltopectoral incision is developed, and the deltopectoral interval is utilized to visualize the subscapularis. The subscapularis is split at the junction of its upper two-thirds and lower one-third. Careful dissection is used to develop the subscapularis split from lateral to medial because the prior coracoid transfer affects the native neurovascular anatomy medially. If substantial coracoid bone remains from the previous transfer, a conjoined tendon tenotomy can be performed to further aid in visualization. Next, any associated hardware is removed, and the coracoid bone remnant is removed. The glenoid defect is sized, and the osseous glenoid bed is prepared. A fresh-frozen distal tibial allograft is then fashioned, washed of marrow elements, and enhanced with platelet-rich plasma before being fixed to the glenoid with use of 2 cortical screws in a lagged fashion. The capsule and subscapularis split are then closed to complete the repair.

ALTERNATIVES

Alternatives to revision glenoid reconstruction with distal tibial allograft include reconstruction with an iliac crest autograft, distal clavicular autograft, revision coracoid transfer, or nonoperative treatment through rehabilitation and activity modification.

RATIONALE

In cases of failed coracoid transfer for anterior shoulder instability with associated glenoid bone loss, distal tibial allograft is the superior revision treatment option for several reasons: it allows for an osteoarticular graft, offers flexibility in terms of graft size, and requires no donor-site morbidity. Distal tibial allograft allows active, high-risk patients to have restored and maintained stability with low complication and graft-resorption rates.

EXPECTED OUTCOMES

Glenoid reconstruction with a distal tibial allograft is associated with improved patient-reported outcomes from preoperatively, as well as recurrence rates of <10% and graft-union rates of >90%.

IMPORTANT TIPS

Initiating the procedure with an arthroscopic evaluation allows for a complete diagnostic examination, including the Hill-Sachs lesion, articular cartilage, and rotator cuff, as well as removal of any loose bodies, which are frequently present and sometimes difficult to visualize and access during the open procedure.A subscapularis split allows for maintenance of the subscapularis insertion on the lesser tuberosity as well as minimal disruption of the muscle fibers.A conjoined tendon tenotomy can provide improved access for hardware removal if the coracoid bone graft from the prior transferred coracoid is present.A 5.5-mm arthroscopic burr is utilized to decorticate the anterior aspect of the glenoid, which facilitates graft union because the burr allows built-in suction capability during constant irrigation, minimizing the possibility of heat necrosis.The distal tibial allograft is thoroughly lavaged to remove residual marrow elements prior to insertion in order to diminish potential immunogenicity.Two solid, fully threaded 3.5-mm cortical screws are placed in a lagged fashion to fix the distal tibial allograft to the glenoid.