Content area
Full text
abstract
Full article available online at OrthoSuperSite.com/view.asp?rID=33723
Posterior glenoid bone loss often is seen in association with glenohumeral osteoarthritis. Many different techniques have been proposed to account for this bone loss during total shoulder arthroplasty, the most popular being eccentric anterior reaming. However, the amount of correction that can be achieved has not been been well quantified. The purpose of this study was to define the amount of eccentric posterior glenoid wear that can be corrected by anterior glenoid reaming. Eight cadaveric scapulae were studied. Simulations of posterior glenoid wear in 5° increments were performed on each scapula. The specimens were then eccentrically reamed to correct the deformity. Anteroposterior width, superior-inferior height, and the best-fit pegged glenoid prosthesis size were measured. Anterior reaming to correct a 10° posterior defect resulted in a decrease in anteroposterior glenoid diameter from 26.7±2.5 mm to 23.8±3.1 mm (P=.006). In 4 of 8 specimens, placing a glenoid prosthesis was not possible after correcting a 15° deformity because of inadequate bony support (N±2), peg penetration (N=1) or both (N=1). A 20°: deformity was correctable in 2 of 8 specimens and only after downsizing the glenoid component. Anterior glenoid reaming to correct eccentric posterior wear of≥10° results in significant narrowing of the anteroposterior glenoid width. A 15° deformity has only a 50% chance of successful correction by anterior, eccentric reaming. Orthopedic surgeons need to be cognizant of this in their preoperative planning for total shoulder arthroplasty.
Glenohumeral osteoarthritis often exhibits a pattern of eccentric posterior glenoid erosion.1,2 This poses a difficult problem that must be corrected during total shoulder arthroplasty to prevent abnormal loading, instability, and poor clinical results.3-6 Various techniques have been proposed to correct excessive glenoid retroversion, including increased humeral anteversion, bone grafting, use of an augmented glenoid component, or eccentric reaming of the glenoid.7,8
Many authors have advocated bone grafting to correct severe glenoid deformities. 9,10 Neer and Morrison11 recommended augmentation of the glenoid when instability can not be corrected by standard techniques, by either making minor changes in humeral version or contouring the glenoid subchondral bone. However no quantitative guidelines were given. Ibarra et al10 suggested that bone grafting or the use of a custom glenoid component may be necessary to correct deformities ≥20°:, but no justification...