Faculty Bibliography

STUDY DESIGN: In vitro laboratory study. OBJECTIVE: The purpose of this study was to identify the effect of dilute povidone-iodine (PVI) solutions on human osteoblast, fibroblast and myoblast cells in vitro. SUMMARY OF BACKGROUND DATA: Dilute PVI wound lavage has been used successfully in spine and joint arthroplasty procedures to prevent post-operative surgical site infection, but their biologic effect on host cells is largely unknown. METHODS: Human primary osteoblasts, fibroblasts, and myoblasts were expanded in cell culture and subjected to various concentrations of PVI (0%, 0.001%, 0.01%, 0.1%, 0.35%, 1%) for 3 minutes. To assess the effect of PVI on cell migration, a scratch assay was performed, in which a "scratch" was made by a standard pipette tip in a cell monolayer following PVI exposure, and time to closure of the scratch was evaluated. Cell survival and proliferation was measured 48 hours post-PVI exposure using a cell viability and cytotoxicity assay. RESULTS: Closure of the scratch defect in all cell monolayers was achieved in < 24 hours in untreated controls and following exposure to PVI concentrations < 0.1%. The scratch defect remained open indefinitely following exposure to PVI concentrations of >/= 0.1%. PVI concentrations < 0.1% did not have significant effect on survival rates compared with control for all cell types. Cells exposed to PVI >/= 0.1% had cell survival rates of less than 6% (p < 0.05). CONCLUSIONS: Clinically used concentration of PVI (0.35%) exerts a pronounced cytotoxic effect on osteoblasts, fibroblast, and myoblasts in vitro. Further investigation is required to systematically study the effect of PVI on tissue healing in vivo and also determine a safe and clinically potent concentration for PVI lavage. LEVEL OF EVIDENCE: N/A.

Arthroscopic SLAP tear repair has become an increasingly used treatment for patients presenting with symptomatic SLAP tears after failed nonoperative management. Debridement, SLAP repair, and open or arthroscopic biceps tenodesis or tenotomy have been used for the treatment of SLAP tears. Various techniques for repair have been described, and furthermore, there is a high incidence of concomitant pathology of the shoulder. Repair remains an excellent option in isolated SLAP tears amenable to repair, with excellent outcomes in well-indicated patients. We present a method for repairing a SLAP tear using standard suture anchor fixation, anterior and posterior portals, and an accessory portal of Wilmington. Adequate labral repair can be achieved with this technique in patients with no concomitant biceps pathology. This report highlights this technique for SLAP repair in patients with isolated symptomatic SLAP tears that have failed conservative management.

BACKGROUND: Intraoperative anesthetic typically consists of either general anesthesia (GA) or isolated regional anesthesia (RA). METHODS: A retrospective propensity-matched cohort analysis on patients undergoing TSA was performed to determine differences between GA and RA in regard to patient population, complications, LOS and hospital readmission. RESULTS: 4158 patients underwent TSA with GA or isolated RA. Propensity-matching resulted in 912 patients in each cohort. RA had lower overall in-hospital complications and greater homebound discharge disposition with lower 90-day readmission rates than GA. CONCLUSION: After TSA, isolated RA was associated with lower in-hospital complications, readmission rates and odds of hospital readmission than GA.

BACKGROUND:This study quantifies the rate of improvement after anatomic and reverse total shoulder arthroplasty; a better understanding of the rate of improvement associated with each prosthesis type may better establish patient expectations for recovery. METHODS:Prospectively collected data on 1,183 patients who underwent either anatomic total shoulder arthroplasty (n = 505) or reverse total shoulder arthroplasty (n = 678) were collected. The Simple Shoulder Test (SST), University of California at Los Angeles (UCLA) Shoulder, American Shoulder and Elbow Surgeons (ASES), Constant, and Shoulder Pain and Disability Index (SPADI) scores, along with range of motion, were recorded preoperatively and at routine postoperative time points. All included patients had a minimum follow-up of 2 years. The rate of improvement of these outcome measures was quantified for patients who underwent anatomic total shoulder arthroplasty and those who underwent reverse total shoulder arthroplasty to compare recovery over time. RESULTS:In this study, 3,587 visits by 1,183 patients were analyzed and several differences between prosthesis types were noted. Patients who underwent reverse total shoulder arthroplasty experienced larger improvements in the Constant score and active forward flexion, and patients who underwent anatomic total shoulder arthroplasty demonstrated better improvement in external rotation compared with patients who underwent reverse total shoulder arthroplasty at nearly all time points. By 72 months, improvement in flexion and abduction decreased for each prosthesis type, but in particular for reverse total shoulder arthroplasty. Full improvement was achieved by 24 months, although the majority of improvement was achieved in the first 6 months, with all 5 scoring metrics following a similar rate of improvement. The ASES, SPADI, and UCLA Shoulder scores closely mirrored each other in the magnitude of improvement, and the SST score demonstrated the largest improvement and the Constant score demonstrated the smallest improvement for both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty. CONCLUSIONS:Both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty reliably result in improved patient outcomes. However, anatomic total shoulder arthroplasty more reliably improves range of motion, particularly external rotation. Most improvement occurs by 6 months, with some additional improvement up to 2 years for both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty. Although the indications for anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty are substantially different, in addition to the biomechanical differences, the improvement in outcome scores over time can be expected to be very similar. This study is helpful to patients and health-care providers to establish expectations regarding the rate of recovery after total shoulder arthroplasty. LEVEL OF EVIDENCE/METHODS:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Purpose: The intrawound application of lyophilized vancomycin has been reported to significantly decrease the rates of perioperative infection in arthroplasty and spine procedures. The local effect of clinically used supra-therapeutic concentration of intra wound vancomycin on surrounding healing tissue has been a topic of continued investigation. The purpose of this study was to examine the in vitro cytotoxicity profile of vancomycin hydrochloride on osteoblasts, fibroblast, and myoblasts. Methods: Human primary osteoblasts (Lonza), fibroblasts (Lonza), and myoblasts (DV Biologics) were expanded and passaged in sterile polystyrene tissue culture flasks and plated at a density of 10,000 cells/cm2. Cells were exposed to vancomycin hydrochloride (Sigma-Aldrich) at concentrations of 1, 3, 6, or 12 mg/cm2. To assess the effect of vancomycin on cell migration, a scratch assay was performed, in which a "scratch" was made in a cell monolayer following vancomycin exposure, and images were subsequently captured at regular intervals until cellular closure of the scratch. Cell survival was measured 48 hours post-vancomycin exposure using a cell cytotoxicity assay (Cell Counting Kit-8, Dojindo). Results: Vancomycin concentrations greater than or equal to 1 mg/cm2 decreased survival of myoblasts and osteoblasts to less than 11% relative to control. Vancomycin greater than or equal to 3 mg/ cm2 decreased fibroblast survival to less than 8% relative to control (Fig. 1). Vancomycin concentrations of 1 mg/cm2 did not significantly affect the survival of fibroblasts. Closure of the scratch defect was observed in less than 24 hours for all control conditions. In myoblasts and osteoblasts, the scratch defect remained open indefinitely following exposure to vancomycin concentrations greater than or equal to 1 mg/cm2. Closure of the scratch defect in fibroblasts was observed in less than 36 hours following exposure to vancomycin of 1 mg/cm2, and remained opened indefinitely following exposure to vancomycin greater than or equal to 3 mg/cm2. Conclusions: Vancomycin has a significant cytotoxic effect on proliferating osteoblasts and myoblasts at concentrations greater than (Figure Presented) or equal to 1 mg/cm2.Vancomycin has a pronounced cytotoxic effect on fibroblasts at concentrations greater than or equal to 3 mg/cm2. Further in vivo studies are warranted to investigate the effect of high local concentrations of vancomycin on infection, bony fusion, and wound healing

Introduction: While total shoulder arthroplasty (TSA) is generally associated with good to excellent outcomes in majority of patients, the integrity and the function of the subscapularis tendon may be compromised after the procedure and lead to inferior outcomes. Therefore, the efficacy of a subscapularis sparing TSA procedure was evaluated in a prospective, double blinded, randomized study. Methods: With IRB approval, patients with end stage osteoarthritis of the shoulder were enrolled into a prospective clinical trial from 2010 to 2014. These patients were randomized into two groups. Group 1 patients were treated with TSA using the subscapularis sparing surgical approach in which the prosthesis was inserted entirely through the rotator interval without violating the subscapularis tendon (SPARING). Group 2 patients were treated with TSA using the standard surgical approach with subscapularis tenotomy (STANDARD). Both the patient and the evaluators remained "blinded" to the surgical approach throughout the study period. Minimum 2 year outcome data was collected using the visual analog score (VAS) for pain and the American Shoulder and Elbow Surgeon (ASES) outcome score. Results: A total of 107 shoulders were enrolled (57 SPARING, 50 STANDARD). Of these, 14 TSA procedures could not be completed as initially randomized. In addition, 3 patients expired (unrelated to the procedure), 7 patients withdrew from the study, and 2 moved away. Of the remaining 81 patients, 2 year outcome data could not be collected from another 11. Thus, complete 2 year outcome data was collected from 32 SPARING and 38 STANDARD patients at an average follow up of 31.1 and 34.4 months, respectively. The ASES score and VAS for the SPARING group improved significantly from 29.3 +/- 12.5 and 6.6 +/- 2.1 to 82.6 +/- 18.8 and 1.6 +/- 2.2 (mean +/- standard deviation). Similarly, the ASES score and VAS for the STANDARD group also improved significantly from 32.8 +/- 16.1 and 6.3 +/- 2.4 to 87.1 +/- 14.5 and 1.0 +/- 1.7. In comparison to their pre-operative status, the ASES score for the SPARING and the STANDARD groups improved 53.9 +/- 22.3 and 54.0 +/- 18.7 points, respectively. The VAS for the SPARING and the STANDARD groups also improved 5.1 +/- 3.1 and 5.3 +/- 2.5 points, respectively. Neither of these differences between the SPARING and the STANDARD groups reached statistical significance. Complication profiles were similar in both groups with 3 in the SPARING group and 2 patients in the STANDARD group requiring revision surgery during the study period. Discussion: At a short term follow up, the outcome of TSA using the subscapularis sparing surgical approach was similar to that after TSA using the standard surgical approach. Future studies with longer follow up of these patients will be required to document the potential benefits of this surgical technique

Total hip arthroplasty has been utilized for the past 50 years as an effective treatment for degenerative, inflammatory and traumatic disorders of the hip. The design of these implants has generally followed the anatomy of the hip as a ball and socket joint with the femoral head representing the ball and the acetabulum representing the socket. We describe a novel hip arthroplasty design in which the "ball" is located on the acetabular side and the "socket" is located on the femoral side. The results of extensive biomechanical testing are described and document wear and corrosion characteristics that are at least equivalent to standard designs. These results support clinical assessment as the next step of the evaluation.

BACKGROUND: Scapular notching is a complication unique to reverse total shoulder arthroplasty (rTSA), although its clinical implications are unclear and remains controversial. METHODS: We retrospectively reviewed rTSA patients of a single implant design in 476 shoulders with a minimum 2-year clinical and radiographic follow-up. Clinical measures included active range of motion and American Shoulder and Elbow Surgeons scores, in addition to one or more of the Constant score, Shoulder Pain and Disability Index, Simple Shoulder Test (SST), and University of California, Los Angeles Shoulder Rating Scale. Complications and rates of humeral radiolucencies were also recorded. RESULTS: Scapular notching was observed in 10.1% (48 of 476) of rTSAs and was associated with a longer clinical follow-up, lower body weight, lower body mass index, and when the operative side was the nondominant extremity. Patients with scapular notching had significantly lower postoperative scores on the Shoulder Pain and Disability Index, Constant, Simple Shoulder Test, and University of California, Los Angeles, Shoulder Rating Scale compared with patients without scapular notching. Patients with scapular notching also had significantly lower active abduction, significantly less strength, and trended toward significantly less active forward flexion (P = .0527). Finally, patients with scapular notching had a significantly higher complication rate and trended toward a significantly higher rate of humeral radiolucent lines (P = .0896) than patients without scapular notching. CONCLUSIONS: This large-scale outcome study demonstrates that patients with scapular notching have significantly poorer clinical outcomes, significantly less strength and active range of motion, and a significantly higher complication rate than patients without scapular notching. Longer-term follow-up is necessary to confirm that these statistical observations in the short-term will result in greater clinically meaningful differences over time.

BACKGROUND: Periprosthetic shoulder infections (PSIs) are challenging to treat and often result in significant patient morbidity. Without a standardized treatment protocol, PSIs are often managed similarly to periprosthetic hip and knee infections. Because 2-stage revision is the gold standard for treating periprosthetic hip and knee infections, we performed a case series and literature review to determine its effectiveness in PSIs. METHODS: We identified 19 patients (14 men) from our institution who were treated with a 2-stage revision after presenting with a PSI. Mean patient age was 63 +/- 9 years, and average body mass index was 30.8 +/- 5.8. The average time from the index arthroplasty to treatment was 40 months, 8 of 13 positive cultures were Propionibacterium acnes, and 9 of 19 patients had multiple shoulder operations before presenting with infection. Minimum follow-up for all patients was 2 years. RESULTS: After a mean follow-up of 63 months (range, 25-184 months), 15 of 19 patients in our study were successfully treated for PSI. Average postoperative American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment score was 69 (range, 32-98) and average postoperative forward elevation was significantly increased from 58 degrees to 119 degrees (P < .001). The incidence of recurrent infection was 26%. The rate of noninfection complications was 16%, for a total complication rate of 42%. CONCLUSION: In patients with PSIs, especially those with intractable, chronic infections, a 2-stage revision represents a viable treatment option for eradicating infection and restoring function. However, it is important to recognize the risk of recurrent infection and postoperative complications in this challenging patient population.

BACKGROUND: Revision shoulder arthroplasty is a technically challenging procedure. It is associated with increased blood loss and operative time, and it frequently necessitates revision implants, augments, and bone-grafting. Shoulder arthroplasty systems with a convertible-platform humeral stem have been developed to reduce the complexity of revision procedures by eliminating the need for humeral component explantation when converting from anatomic shoulder arthroplasty (hemiarthroplasty or total shoulder arthroplasty) to reverse total shoulder arthroplasty (rTSA). METHODS: A multicenter, retrospective analysis involving 102 consecutive shoulders (102 patients) that underwent revision of an anatomic shoulder arthroplasty to an rTSA was conducted. During the revision, 73 of the shoulders needed exchange of the humeral stem (the exchange group) and 29 had retention of a convertible-platform humeral component (the retention group). Patient demographics, operative time, blood management, range of motion, complications, and patient-reported outcomes were compared between the 2 groups. RESULTS: Patients with retention had significantly shorter operative time (mean and standard deviation, 130 +/- 48 versus 195 +/- 58 minutes; p < 0.001) and lower estimated blood loss (292 +/- 118 versus 492 +/- 334 mL; p = 0.034). The rate of intraoperative complications was lower in the retention group (0% versus 15%; p = 0.027). Patients with retention had slightly better postoperative range of motion (active external rotation, 26 degrees +/- 23 degrees versus 11 degrees +/- 23 degrees [p = 0.006]; active forward elevation, 112 degrees +/- 37 degrees versus 96 degrees +/- 33 degrees [p = 0.055]). CONCLUSIONS: Shoulder arthroplasty systems that utilize a convertible-platform humeral stem offer an advantage for rTSA conversion in that a well-fixed, well-positioned humeral stem can be retained. There were significantly fewer complications as well as significantly decreased blood loss and operative time when a convertible-platform stem was utilized (p < 0.050). LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.