Faculty Bibliography

BACKGROUND: Significant attempts have been made to adopt practices to minimize blood transfusion after total joint arthroplasty (TJA) because of transfusion cost and potential negative clinical consequences including allergic reactions, transfusion-related lung injuries, and immunomodulatory effects. We aimed to evaluate risk factors for blood transfusion in a large cohort of TJA patients. METHODS: We used the all-payer California Healthcare Cost and Utilization Project data from 2006 to 2011 to examine the trends in utilization of blood transfusion among arthroplasty patients (n = 320,746). We performed descriptive analyses and multivariate logistic regression clustered by hospital, controlling for Deyo-Charlson comorbidity index, age, insurance type (Medicaid vs others), gender, procedure year, and race/ethnicity. RESULTS: Eighteen percent (n = 59,038) of TJA patients underwent blood transfusion during their surgery, from 15% with single knee to 45% for bilateral hip arthroplasty. Multivariate analysis indicated that compared with the referent category of single knee arthroplasty, single hip had a significantly higher odds of blood transfusion (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.68-1.83), as did bilateral knee (OR, 3.57; 95% CI, 3.20-3.98) and bilateral hip arthroplasty (OR, 6.17; 95% CI, 4.85-7.85). Increasing age (eg, age >/=80 years; OR, 2.99; 95% CI, 2.82-3.17), Medicaid insurance (OR, 1.36; 95% CI, 1.27-1.45), higher comorbidity index (eg, score of >/=3; OR, 2.33; 95% CI, 2.22-2.45), and females (OR, 1.75; 95% CI, 1.70-1.80) all had significantly higher odds of blood transfusion after TJA. CONCLUSION: Primary hip arthroplasties have significantly greater risk of transfusion than knee arthroplasties, and bilateral procedures have even greater risk, especially for hips. These factors should be considered when evaluating the risk for blood transfusions.

BACKGROUND: Although HbA1c is commonly used for assessing glycemic control before surgery, there is no consensus regarding its role and the appropriate threshold in predicting adverse outcomes. This study was designed to evaluate the potential link between HbA1c and subsequent periprosthetic joint infection (PJI), with the intention of determining the optimal threshold for HbA1c. METHODS: This is a multicenter retrospective study, which identified 1645 diabetic patients who underwent primary total joint arthroplasty (1004 knees and 641 hips) between 2001 and 2015. All patients had an HbA1c measured within 3 months of surgery. The primary outcome of interest was a PJI at 1 year based on the Musculoskeletal Infection Society criteria. Secondary outcomes included orthopedic (wound and mechanical complications) and nonorthopedic complications (sepsis, thromboembolism, genitourinary, and cardiovascular complications). A regression analysis was performed to determine the independent influence of HbA1c for predicting PJI. RESULTS: Overall 22 cases of PJI occurred at 1 year (1.3%). HbA1c at a threshold of 7.7 was distinct for predicting PJI (area under the curve, 0.65; 95% confidence interval, 0.51-0.78). Using this threshold, PJI rates increased from 0.8% (11 of 1441) to 5.4% (11 of 204). In the stepwise logistic regression analysis, PJI remained the only variable associated with higher HbA1c (odds ratio, 1.5; confidence interval, 1.2-2.0; P = .0001). There was no association between high HbA1c levels and other complications assessed. CONCLUSION: High HbA1c levels are associated with an increased risk for PJI. A threshold of 7.7% seems to be more indicative of infection than the commonly used 7% and should perhaps be the goal in preoperative patient optimization.

BACKGROUND: Many cost drivers of total knee arthroplasty (TKA) have been critically evaluated to meet the heightened quality-associated expectations of performance-based care. However, assessing the efficacy of the different modalities of skin closure has been an underappreciated topic. The present study aims to provide further insight by conducting a meta-analysis and systematic review evaluating the rates of common complications and perioperative quality outcomes associated with different suture and staple skin closure techniques after TKA. METHODS: The present study was conducted in accordance with both the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement and the Cochrane Handbook for meta-analyses and systematic reviews. Primary outcome measures evaluated rates of common complications associated with primary TKA. Secondary outcome measures evaluated wound closure time, direct surgical costs, and cosmetic and knee function outcomes. RESULTS: Our meta-analysis demonstrated that skin sutures had a higher likelihood of superficial and deep infections, abscess formation, and wound dehiscence. Conversely, staples had a higher tendency for prolonged wound discharge. A systematic review of wound closure times and overall resource utilization demonstrated that wound closure was faster and more cost-effective with skin staples than sutures. CONCLUSION: Primary skin incision closure with staples demonstrated lower wound complications, decreased wound closure times, and an overall reduction in resource utilization. Given these outcomes, the use of staples after TKA may have several subtle clinical advantages over sutures.

BACKGROUND: A large component of the cost of revision total hip arthroplasty (THA) is the cost of the implants. We examined the pricing of revision THA implants to determine the possible savings of different pricing models. METHODS: From our institutional database, all revision THAs done from 9/1/2013 to 8/31/2014 were identified. The cost of the implants was analyzed as a percentage of the total cost of the hospitalization and compared to direct to hospital and fixed implant pricing models. RESULTS: Of 153 revision THAs analyzed, the cost of implants amounted to 36% of the total hospital cost. The direct to hospital cost and fixed implant pricing models would reduce the cost of an all-component revision to $4395 (saving $8962 per case) and $5000 (saving $8357 per case). CONCLUSION: Both fixed implant pricing and the direct to hospital pricing models would result in a decrease in revision implant costs.

BACKGROUND: Short-term and intermediate-term wear rates for highly cross-linked polyethylene (HCLPE) liners in total hip arthroplasty (THA) are significantly lower than published rates for traditional polyethylene liners. The aim of this study was to report the longest-to-date follow-up of a specific HCLPE liner. METHODS: A series of 35 THAs using a specific HCLPE liner were reviewed. Anteroposterior radiographs were reviewed for femoral head penetration, the presence of femoral and/or acetabular osteolysis, long-term survival, total wear, and wear rates in all patients. RESULTS: The average patient age at time of surgery was 70 years with an average follow-up of 10 years (118 months; range, 7.2-13.4 years). The mean wear rate in our cohort was 0.07 mm/y. Total wear was 0.71 mm over the study period. No hips showed evidence of osteolysis in any zones. Survivorship at latest follow-up was 100% with all-cause revision as an end point. CONCLUSION: The wear rate of HCLPE liners continues to be lower than published wear rates for traditional polyethylene and continues to reaffirm the acceptably low wear rates using HCLPE acetabular liner in primary THA.

BACKGROUND: Accurate measurement of acetabular cup position (CP), changes in leg length (LL), and offset (OS) are paramount in ensuring proper sizing and implantation of components during total hip arthroplasty (THA). LL/OS inaccuracies can cause low back pain, neurological deficits, and patient dissatisfaction, while inaccurate positioning of the acetabular cup can lead to instability, dislocation, and, ultimately, revision surgery. The objective of this study was to evaluate the accuracy of a mini-navigation tool in measuring CP and LL/OS differential during THA. MATERIALS AND METHODS: Three board-certified orthopedic surgeons each performed four THA procedures via the posterior approach on six cadavers (12 hips) utilizing a novel mini-navigation tool. Imaging included pre- and post-operative radiographs and post-operative CT scans. Image analysis was performed by two radiologists not involved in the surgical procedures. System accuracy regarding measurement of cup position (anteversion and inclination) was determined by comparing the CT measurement of cup orientation with data gathered intraoperatively by probing the face of the implanted cup with the navigation tool and recording the coordinates. RESULTS: The mean absolute difference between CT and device measurements of cup position was 0.74 masculine (SD: 0.47, range: 0.19-1.48) for anteversion and 0.97 masculine (SD: 0.67, range: 0.27-2.57) for inclination. The mean difference between device and radiograph measurements of LL changes was 0.27 mm (SD: 3.61, range: -5.20-7.78) (absolute mean: 2.71+/-2.25 mm), while the mean difference in OS was 1.75 mm (SD: 3.00, range: -2.47-6.65) (absolute mean: 2.37+/-2.44 mm). CONCLUSIONS: This novel mini-navigation tool measured CP, LL, and OS accurately when compared with implant position measured on imaging.

PURPOSE: The objective of this study was to quantify the amount of ensuing internal rotation of the tibial component when positioned along the medial border of the tibial tubercle, thus establishing a reproducible intraoperative reference for tibial component rotational alignment during total knee arthroplasty (TKA). METHODS: The angle formed from the tibial geometric centre to the intersection of both lines from the middle of the tibial tuberosity and its medial border was measured in 50 patients. The geometric centre was determined on an axial CT slice at 10 mm below the lateral tibial plateau and transposed to a slice at the level of the most prominent part of the tibial tuberosity. Similar measurements were taken in 25 patients after TKA, in order to simulate the intraoperative appearance of the tibia after making its proximal resection. RESULTS: This angle was found to be similar (n.s.) in normal and post-TKA tibiae [median 20.4 degrees (range 15 degrees -24 degrees ) vs. 20.7 degrees (range 16 degrees -25 degrees ), respectively]. In 89.3 % of the patients, the angle ranged from 17 degrees to 24 degrees . No statistical difference (p n.s.) was found between women and men in both normal [median -20.7 degrees (range 16 degrees -25 degrees ) vs. 19.9 degrees (range 15 degrees -24 degrees )] and post-TKA tibiae [median 21.4 degrees (range 19 degrees -24 degrees ) vs. 20 degrees (range 16 degrees -25 degrees )]. CONCLUSION: This study found that in 90 % of the patients, the medial border of the tibial tuberosity is internally rotated 17 degrees -24 degrees in relation to the line connecting the middle of the tuberosity to the tibial geometric centre. Since this anatomical landmark may be more easily identifiable intraoperatively than the commonly used "medial 1/3", it can provide a better quantitative reference point and help surgeons achieve a more accurate tibial implant rotational position. LEVEL OF EVIDENCE: Cohort and case control studies, Level III.

BACKGROUND: To our knowledge, no study has assessed the ability of rigid patient positioning devices to afford arthroplasty surgeons with ideal acetabular orientation throughout surgery. The purpose of this study is to use robotic arm-assisted computer navigation to assess the reliability of pelvic position in total hip arthroplasty performed on patients positioned with rigid positioning devices. METHODS: A prospective cohort of 100 hips (94 patients) underwent robotic-guided total hip arthroplasty in the lateral decubitus position from the posterior approach, 77 stabilized by universal lateral positioner, and 23 by peg board. Before reaming, computed tomography-templated computer software generated true values of pelvic anteversion and inclination based on the position of the robot arm registered to the patient's preoperative pelvic computed tomography. RESULTS: Mean alteration in anteversion and inclination values was 1.7 degrees (absolute value, 5.3 degrees ; range, -20 degrees to 20 degrees ) and 1.6 degrees (absolute value, 2.6 degrees ; range, -8 degrees to 10 degrees ), respectively. And 22% of anteversion values were altered by >10 degrees and 41% by >5 degrees . There was no difference between hip positioners used (P = .36). Anteversion variability was correlated with body mass index (P = .02). CONCLUSION: Despite the use of rigid patient positioning devices-a lateral hip positioner or peg board-this study reveals clinically important malposition of the pelvis in many cases, especially with regard to anteversion. These results show a clear need to pay particular attention to anatomic landmarks or computer-assisted techniques to assure accurate acetabular cup positioning. Patient positioning should not be solely trusted.

OBJECTIVE: Orthopedic residents commonly perform closed manipulative reductions as a part of their training. Traditionally, this skill is taught early in training but difficult to simulate. Proficiency is achieved through repetition and experience; faculty observation and instruction is unfortunately often limited. Direct resident teaching has been shown to increase competency, comfort, and long-term skill retention. We hypothesize that video review of closed fracture reductions will provide an inexpensive and valuable tool for resident education and improve skill performance. DESIGN: Closed reductions performed by orthopaedic residents were recorded using a secured mobile tablet device in the emergency department (ED). Video review sessions were performed with both peer and faculty feedback/analysis of reduction technique. Anonymous resident and faculty surveys were completed following each session to evaluate the usage and perceived benefit of the program. SETTING: University-based Level I Trauma Center. PARTICIPANTS: Orthopedic surgery residents and faculty. RESULTS: All junior orthopedic residents (postgraduate year [PGY] 1-3) reported that direct video observation by faculty was beneficial. Furthermore, 97% of junior resident and 100% of faculty responses reported that they would use this educational technology in the future. Residents and faculty both strongly agreed that video review was more useful than other methods, improved resident preparation for ED fracture care, and felt this technique would improve patient care and outcomes. Compared with senior residents (PGY 4-5), PGY-1s believed that this technique helped them prepare for ED fracture care (p = 0.02). CONCLUSIONS: Video review provides a useful, innovative, and inexpensive method to improve resident competency in closed fracture reduction-a critical skill in orthopedic patient care. These procedures are uncommonly available for direct faculty observation. We have demonstrated that both residents and faculty were satisfied with the ability to review procedures, identify weaknesses, and obtain or provide direct feedback on this skill. Additionally, fracture reduction video review may help residents meet and achieve clinical milestones, an area of future investigation.

BACKGROUND: Changes in spinal alignment and pelvic tilt alter acetabular orientation in predictable ways, which may have implications on stability of total hip arthroplasty (THA). Patients with sagittal spinal deformity represent a subset of patients who may be at particularly high risk of THA instability because of postural compensation for abnormal spinal alignment. METHODS: Using standing stereoradiography, we evaluated the spinopelvic parameters, acetabular cup anteversion, and inclination of 139 THAs in 107 patients with sagittal spinal deformity. Standing images were compared with supine pelvic radiographs to evaluate dynamic changes in acetabular cup position. Dislocation and revision rates were procured through retrospective chart review. The spinal parameters and acetabular cup positions among dislocators were compared with those who did not dislocate. RESULTS: The rate of THA dislocation in this cohort was 8.0%, with a revision rate of 5.8% for instability. Patients who sustained dislocations had significantly higher spinopelvic tilt, T1-pelvic angle, and mismatch of lumbar lordosis and pelvic incidence. Among all patients, 78% had safe anteversion while supine, which decreased significantly to 58% when standing due to increases in spinopelvic tilt. Among dislocating THA, 80% had safe anteversion, 80% had safe inclination, and 60% had both parameters within the safe zone. CONCLUSION: In this cohort, patients with THA and concomitant spinal deformity have a particularly high rate of THA instability despite having an acetabular cup position traditionally thought of as within acceptable alignment. This dislocation risk may be driven by the degree of spinal deformity and by spinopelvic compensation. Surgeons should anticipate potential instability after hip arthroplasty and adjust their surgical plan accordingly.