Faculty Bibliography

BACKGROUND: We describe the features of modern and historical bicruciate-retaining (BCR) total knee arthroplasty (TKA) implants compared with other TKA implant designs, reviewing kinematics, proprioception, operative technique, and clinical results. METHODS: We performed a review based on PubMed, Embase, CINAHL Plus, and Cochrane databases from January 1990 to April 2016 using combinations of the following keywords: "bicruciate-retaining arthroplasty," "bicruciate-retaining total knee arthroplasty," "bicruciate-retaining TKA," "kinematics," "knee kinematics," and "TKA kinematics." RESULTS: Four studies have supported the notion that preservation of both cruciate ligaments in TKA preserves more "normal" knee kinematics. BCR implants provide greater proprioceptive performance when compared with posterior cruciate-retaining (CR) TKA implants. However, the operative implantation is more challenging with BCR TKAs, requiring the surgeon to take additional precautions. Overall, there did not seem to be a significant difference in short-term clinical outcomes between the BCR and CR implants. CONCLUSIONS: The utility of BCR TKA is still debatable. The literature has not shown clear indications and guidelines for the value and use of this implant. Although kinematics have been shown to mirror the native knee more closely, the clinical outcomes of BCR vs CR TKAs do not differ significantly. Moreover, additional care must be taken when inserting a BCR implant. The anterior cruciate ligament exploration and preservation is more challenging and certain preparation and precautions must take place. Overall, we have not found that BCR implants are significantly superior to CR implants with regards to short term clinical outcomes despite the BCR TKA having improved kinematics and proprioception.

PURPOSE: How changes in the surgical team's culture can potentially reduce operating room (OR) traffic. INTRODUCTION: Excessive OR traffic during surgical procedures can present a risk to the patient's safety and recovery. Data suggest that limiting the number of OR personnel during the intraoperative period can reduce excessive OR traffic. However, it is unclear whether the surgeon's verbal intervention can also successfully reduce intraoperative OR traffic. This study compares traffic rates in hip and knee arthroplasty cases against traffic rates during nonarthroplasty cases to examine the effects of verbal interventions implemented by the surgeon to reduce intraoperative traffic. METHOD: The study consisted of 16 orthopedic surgeons in a noninterventional group and 1 orthopedic surgeon in the interventional group. The surgeon in the interventional group implemented verbal protocols to OR staff to limit excessive intraoperative traffic. Operating room traffic was monitored for 3 consecutive months (January-March 2015) with the use of infrared automated door counters that tracked door openings when someone entered or left the OR. RESULTS: A total of 50 hip and knee arthroplasties cases and 157 nonarthroplasty cases were tracked during the study period. A total of 134 hours and 4482 movements were collected for the hip and knee arthroplasty cases. A total of 498 hours and 22 902 movements were collected for the nonarthroplasty cases. Comparing the 2 groups, the interventional group averaged 33 movements per hour while the noninterventional group averaged 46 movements per hour (P < .001). CONCLUSIONS: These results suggest that operative room traffic can be reduced through simple verbal protocols established by the surgical team.

Acute blood loss anemia following total joint arthroplasty procedures puts patients at risk for multiple perioperative complications. Preventing symptomatic anemia in the arthroplasty patient population is specifically important because these patients are often at greater risk for myocardial ischemia due to medical comorbidities, and because it delays progression with physical therapy. In addition to maintaining hemostasis with meticulous surgical technique, several techniques have been developed to help surgeons minimize blood loss. Fibrin sprays, antifibrinolytics such as tranexamic acid, hypotensive anesthesia, bipolar sealers, reinfusion drains, and specific techniques for arthrotomy closure are several strategies that have become part of a multimodal approach to minimize blood loss and reduce transfusion requirement associated with total joint arthroplasty. Currently, published evidence most supports the routine use of tranexamic acid and hypotensive anesthesia in standard, primary hip and knee arthroplasty, but specific adjunctive strategies may be considered when warranted by the patient's clinical condition or surgical procedure.

BACKGROUND: Lumbar-pelvic fusion reduces the variation in pelvic tilt in functional situations by reducing lumbar spine flexibility, which is thought to be important in maintaining stability of a total hip arthroplasty (THA). We compared dislocation and revision rates for patients with lumbar fusion and subsequent THA to a matched comparison cohort with hip and spine degenerative changes undergoing only THA. METHODS: We identified patients in New York State who underwent primary elective lumbar fusion for degenerative disc disease pathology and subsequent THA between January 2005 and December 2012. A propensity score match was performed to compare 934 patients with prior lumbar fusion to 934 patients with only THA according to age, gender, race, Deyo comorbidity score, year of surgery, and surgeon volume. Revision and dislocation rates were assessed at 3, 6, and 12 months post-THA. RESULTS: At 12 months, patients with prior lumbar fusion had significantly increased rates of THA dislocation (control: 0.4%; fusion: 3.0%; P < .001) and revision (control: 0.9%; fusion: 3.9%; P < .001). At 12 months, fusion patients were 7.19 times more likely to dislocate their THA (P < .001) and 4.64 times more likely to undergo revision (P < .001). CONCLUSION: Patients undergoing lumbar fusion and subsequent THA have significantly higher risks of dislocation and revision of their hip arthroplasty than a matched cohort of patients with similar hip and spine pathology but only undergoing THA. During preoperative consultation for patients with prior lumbar fusion, orthopedic surgeons must educate the patient and family about the increased risk of dislocation and revision.

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.

BACKGROUND: Valgus cut angle (VCA), defined as the angle between the anatomical and the mechanical axes of femur, is an important parameter upon which a critical step of knee arthroplasty is based. Some variables have been proposed to affect the magnitude of this cut. However, little information is available regarding whether a generic value can be used, or if a patient-specific value from a long leg X-ray, or factors that can be determined preoperatively, is necessary to accurately set the VCA. METHODS: Standard standing 3-joint views were used to measure a number of anatomical measurements in 358 limbs, 202 patients (116 women, 86 men). Neck-shaft angle, medial offset, femoral length (FL), distal femoral articular angle, and VCA were measured. Demographic data including gender and height were extracted from hospital charts. The correlation of VCA with each of the other factors was evaluated using linear regression and t-test and finally multivariate analysis. RESULTS: The average VCA was 5.76 degrees (range 4-8). Gender and distal femoral articular angle were not related to VCA (P = .343 and .995). FL was found to be a function of height with similar effects on multivariate analysis. Only the height (or FL) and femoral offset were identified as independent factors, with a negative correlation for the former (P < .001) and a positive correlation for the latter (P < .001). CONCLUSION: Femoral offset and height are the 2 independent factors determining VCA. Other parameters are indirectly related to these 2 factors. Tall patients with a small femoral offset have smaller VCA and short patients with a large offset have larger VCA. The wide variety of VCA values does not support using a generic value for all patients during knee arthroplasty.

Femoral fractures between a total hip arthroplasty prosthesis and total knee arthroplasty prosthesis, also called interprosthetic fractures, are challenging clinical problems. The number of patients who have undergone ipsilateral primary or revision joint arthroplasty procedures in both the hip and the knee continues to rise, and the number of interprosthetic fractures is increasing, as well. The growing body of biomechanical and clinical literature on interprosthetic fractures reflects the increased frequency of and interest in these injuries. Similar to the management of periprosthetic fractures, the management of interprosthetic fractures depends on the location of the fracture, the stability of the implant, and the ability to achieve stable fracture fixation. These factors are the basis of recently described classification systems and treatment strategies. In patients with stable implants, fracture fixation alone is performed. When the implant is loose, both revision arthroplasty and fracture fixation may be required to provide stability of the limb.

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.

BACKGROUND: The most commonly used postacute care facility after total joint arthroplasty is a skilled nursing facility (SNF). However, little is known regarding the role of physical therapy achievements and insurance status on the decision to discharge from an SNF. In this study, we aim to compare functional outcomes and length of stay (LOS) at an SNF among patients with Medicare vs private health coverage. METHODS: We retrospectively collected physical therapy data for 114 patients who attended an SNF following acute hospitalization for total joint arthroplasty. Medicare beneficiaries were compared with patients covered by Managed Care (MC) policies (health maintenance organization [HMO] and preferred provider organization [PPO]) using several SNF discharge outcomes, including LOS, distance ambulated, and functional independence in gait, transfers, and bed mobility. RESULTS: LOS at the SNF was significantly longer for Medicare patients (Medicare: 24 +/- 22 days, MC: 12 +/- 7 days, P = .007). After adjusting for LOS and covariates, MC patients had significantly greater achievements in all functional outcomes measured. In a study subanalysis, Medicare patients were found to achieve similar functional outcomes by SNF day 14 as MC patients achieved by their day of discharge on approximately day 12. Yet, the Medicare group was not discharged until several days later. CONCLUSION: Medicare status is associated with poor functional outcomes, long LOS, and slow progress in the SNF. Our results suggest that insurance reimbursement may be a primary factor in the decision to discharge, rather than the achievement of functional milestones.