Preoperative three-dimensional computer planning for reverse total shoulder arthroplasty and bone grafting for severe glenoid deformity.

BACKGROUND: Computer assisted planning without patient specific instrumentation may be utilized to guide reverse total shoulder arthroplasty baseplate placement. The purpose of this study was to determine the difference between planned and achieved inclination and retroversion correction with three-dimensional preoperative computer assisted planning in reverse total shoulder arthroplasty without patient specific instrumentation with bone grafting for severe glenoid erosion. METHODS: Preoperative three-dimensional computer assisted planning without patient specific instrumentation was performed on 15 patients undergoing primary reverse total shoulder arthroplasty with glenoid bone grafting for severe glenoid erosion. On preoperative and immediate postoperative computed tomography slices, two-dimensional retroversion and inclination were measured. Preoperative three-dimensional baseline retroversion and inclination and planned postoperative three-dimensional retroversion and inclination were measured. Planned and achieved version and inclination changes were compared. RESULTS: The planned and achieved retroversion corrections were 18° and 12°, respectively (p < 0.001). The planned and achieved inclination corrections were 11° and 11°, respectively (p = 0.803). CONCLUSIONS: Three-dimensional computer assisted planning without patient specific instrumentation in the setting of reverse total shoulder arthroplasty with severe glenoid erosion requiring bone grafting can accurately guide baseplate placement. All cases in which failure to correct retroversion or inclination within 10° of planning occurred in patients with severe erosion (B3 or E3 glenoids), therefore patient specific guides may be warranted in these cases to improve accuracy of implantation. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Structural glenoid allograft reconstruction during reverse total shoulder arthroplasty.

BACKGROUND: Large glenoid defects present a challenge during primary and revision reverse total shoulder arthroplasty (RTSA) especially when humeral head autograft is not available as a bone graft source. The purpose of this study was to evaluate the clinical and radiographic outcomes of RTSA with concomitant structural allografting to reconstruct large glenoid defects. METHODS: From May 2008 to July 2016, 22 patients underwent primary or revision RTSA with structural glenoid allografting. Of 22 patients, 19 (86%) were available for a minimum 2-year clinical follow-up (average, 2.8 ± 1.3 years), and 17 of 22 (77%) were available for a minimum 1-year radiographic follow-up. Functional outcomes, range of motion, radiographic deformity correction, allograft incorporation, and complication rates were determined. RESULTS: From preoperatively to postoperatively, significant improvements in the average Simple Shoulder Test score (2 ± 2 preoperatively vs. 10 ± 8 postoperatively, P = .002), the average American Shoulder and Elbow Surgeons score (31 ± 19 preoperatively vs. 70 ± 25 postoperatively, P < .001), and average active forward elevation (71° ± 41° preoperatively vs. 128° ± 28° postoperatively, P < .001) were noted. Coronal-plane radiographic correction was 29° ± 12° as measured with the reverse shoulder arthroplasty angle (P < .001) and 14° ± 11° as measured with the ß angle (P < .001). Postoperatively, of 17 patients with a minimum 1-year radiographic follow-up, 14 (82%) had complete radiographic incorporation of the graft. Acromial fracture nonunions developed in 2 patients and loosening and migration of the baseplate were found in 2 patients, although no patients elected to undergo further surgery. CONCLUSIONS: RTSA with allograft reconstruction of severe glenoid defects allows restoration of glenoid anatomy and leads to high rates of bony incorporation with low rates of glenoid loosening or requirement for revision. Structural allograft is an excellent alternative to autograft in revision RTSA to avoid graft-site morbidity.

Glenoid Retroversion Associates With Asymmetric Rotator Cuff Muscle Atrophy in Those With Walch B-type Glenohumeral Osteoarthritis.

BACKGROUND: Our purpose was to determine whether glenoid retroversion associates with asymmetric rotator cuff muscle atrophy in eccentric glenohumeral osteoarthritis (GHOA) and if this asymmetry is worsening of GHOA-related atrophy. METHODS: Two groups of shoulder magnetic resonance images were studied: patients older than 50 years without a rotator cuff tear or GHOA (control group) and patients preoperative to anatomic total shoulder arthroplasty (GHOA group). Retroversion and rotator cuff muscle cross-sectional areas were measured using reliable and accurate techniques. Proportional muscle areas were created by dividing by total cuff area to correct for differences in overall patient size. Walch grades were assigned via consensus. RESULTS: The control group consisted of 102 patients and the GHOA cohort consisted of 141 patients. Within the eccentric GHOA group, retroversion associated with relative increasing supraspinatus (r = 0.268, P = 0.035), increasing infraspinatus (r = 0.273, P = 0.032), and decreasing subscapularis areas (r = -0.343, P = 0.006). However, the combined GHOA group had a significantly higher relative subscapularis area than the control group (P = 0.026). CONCLUSION: In the eccentric GHOA, increasing retroversion is associated with increasing volume of the posterior cuff relative to the anterior cuff muscles, which is a reversal of the asymmetric increasing volume of the anterior cuff relative to the posterior cuff muscles seen with concentric GHOA. LEVEL OF EVIDENCE: Diagnostic, level III.

Hydrogen peroxide skin preparation reduces Cutibacterium acnes in shoulder arthroplasty: a prospective, blinded, controlled trial.

BACKGROUND: The purpose of this study was to determine whether preoperative skin preparation with hydrogen peroxide reduces intraoperative culture positivity for Cutibacterium acnes in shoulder arthroplasty. METHODS: This was a prospective, controlled, parallel/noncrossover, nonrandomized, single-blinded trial registered at clinicaltrials.gov. We included a consecutive series of patients scheduled to undergo primary anatomic or reverse total shoulder arthroplasty. The first group of patients underwent a standard skin preparation and the second group underwent the same preparation with the addition of hydrogen peroxide. We then took skin, dermis, glenohumeral joint, and air (negative control) aerobic and anaerobic culture swabs. We blinded the laboratory analyzing the samples. An a priori power analysis determined that 56 patients would be needed to see a 50% reduction in culture positivity rates. We also conducted a post hoc gender-stratified analysis. RESULTS: Between January 2017 and October 2018, the authors performed 124 primary shoulder arthroplasties, of which we included 65 and collected samples on 61. There were no demographic differences. There were fewer patients within the peroxide group with triple-positive cultures (skin, dermis, and joint) (0% vs. 19%, P = .024) and positive cultures from the joint (10% vs. 35%, P = .031). In our subgroup analysis, these differences were only significant in males. The vast majority of positive cultures were with C. acnes. CONCLUSION: Although larger, randomized studies are needed, adding hydrogen peroxide to the preoperative skin preparation may be a low-cost, low-risk method to reduce deep tissue contamination with C. acnes, particularly within males.

An analysis of costs associated with shoulder arthroplasty.

BACKGROUND: The purpose of this study was to identify factors associated with variation in direct costs with shoulder arthroplasty. METHODS: This was a retrospective study of all shoulder arthroplasties performed at a single facility between July 1, 2011, and November 30, 2016. We collected patient factors, indications, procedure (including implant details), implant brand (A, B, and other), and complications. We collected direct costs over a 90-day period using a validated internal tool. We identified patient and procedure characteristics associated with costs using multivariable generalized linear models. RESULTS: A total of 361 patients were included, 19% with revision arthroplasty procedures, 32% with anatomic total shoulder arthroplasties, and 66% with reverse total shoulder arthroplasties (RTSAs). Of total costs, 13% were operative facility utilization costs and 58% were operative supply costs. Factors associated with increased total cost included younger age (P = .002) and an indication for surgery of other, that is, not osteoarthritis, a failed arthroplasty, or the sequelae of a rotator cuff tear (P = .030). Factors associated with increased operative costs included younger age (P = .002), use of an RTSA (P < .001), use of a bone graft (P < .001), implant brand B (P = .098), implant brands other than A and B (P = .04), the sequelae of a rotator cuff tear as an indication for surgery (P = .041), or an indication for surgery of other (P = .007). CONCLUSION: Most short-term (90-day) costs with shoulder arthroplasty are operative costs. Nonmodified factors associated with increased cost included younger age and less common indications for surgery, whereas potentially modifiable factors included the intraoperative use of a bone graft, implant brand, and RTSA use.

Do magnetic resonance imaging and computed tomography provide equivalent measures of rotator cuff muscle size in glenohumeral osteoarthritis?

BACKGROUND: Rotator cuff muscle volume is associated with outcomes after cuff repair and total shoulder arthroplasty. Muscle area on select magnetic resonance imaging (MRI) slices has been shown to be a surrogate for muscle volume. The purpose of this study was to determine whether computed tomography (CT) provides an equivalent measurement of cuff muscle area to a previously validated MRI measurement. METHODS: We included 30 patients before they were undergoing total shoulder arthroplasty with both preoperative CT and MRI scans performed within 30 days of one another at 1 institution using a consistent protocol. We reoriented CT sagittal and MRI sagittal T1 series orthogonal to the scapular plane. On both CT and MRI scans, we measured the area of the supraspinatus, infraspinatus-teres minor, and subscapularis on 2 standardized slices as previously described. We calculated intraclass correlation coefficients and mean differences. RESULTS: For the 30 subjects included, when MRI and CT were compared, the mean intraclass correlation coefficients were 0.989 (95% confidence interval [CI], 0.976-0.995) for the supraspinatus, 0.978 (95% CI, 0.954-0.989) for the infraspinatus-teres minor, and 0.977 (95% CI, 0.952-0.989) for the subscapularis. The mean differences were 0.2 cm2 (95% CI, 0.0-0.4 cm2) for the supraspinatus (P = .052), 0.8 cm2 (95% CI, 0.1-1.4 cm2) for the infraspinatus-teres minor (P = .029), and -0.3 cm2 (95% CI, -1.2 to 0.5 cm2) for the subscapularis (P = .407). CONCLUSION: CT provides nearly equivalent measures of cuff muscle area to an MRI technique with previously validated reliability and accuracy. While CT underestimates the infraspinatus area as compared with MRI, the difference is less than 1 cm2 and thus likely clinically insignificant.