Faculty Bibliography

Background/UNASSIGNED:Proper sizing of femoral and tibial components has been associated with long-term outcomes and survivorship in simultaneous bilateral total knee arthroplasty (SBTKA) and may be a reason for differences in outcomes between knees. The aim of this study compares post-operative outcomes and revision rates in patients undergoing SBTKA with different component sizes. Methods/UNASSIGNED:A retrospective review was conducted at a single academic institution identifying patients who underwent SBTKA from 2011 to 2019. Inclusion criteria included: primary osteoarthritis, similar pre-operative deformity, and same implant manufacturer. The primary outcome compares pre- and post-op (delta, Δ) Knee Society Score-Knee Score (KSS-KS) and range of motion (ROM) between knees. Secondary outcome measures were all-cause revisions rates, including manipulations under anesthesia and arthroscopy with or without lysis of adhesions. Results/UNASSIGNED:149 patients were identified who met the inclusion criteria: 128 patients had femoral size difference (FSD) of 0, 138 patients had tibial size difference (TSD) of 0, 21 patients with FSD of 1, and 11 patients with TSD of 1. There was no difference in ΔKSS-KS or ΔROM in patients for any FSD or TSD. Revisions for aseptic loosening were greater for TSD 1 compared to TSD 0 (p < 0.001). No other differences in cause of revision were identified. Conclusion/UNASSIGNED:A TSD of 1 may be associated with increased revision rates for aseptic loosening in both smaller and larger sized implants. Surgeons may achieve optimal patient outcomes in SBTKA with proper sized implants through increased awareness of component asymmetry and repeat intraoperative evaluation when asymmetrical measurements occur.

Complex regional pain syndrome (CRPS) is an uncommon cause of residual pain after total knee arthroplasty (TKA). The presentation is variable, and there is no gold standard diagnostic test. Diagnosis is more difficult after TKA because some classic signs of CRPS may be unreliable and imaging may be difficult to interpret. Early intervention is the most important factor in predicting improvement, necessitating high suspicion in patients with exaggerated pain and stiffness after excluding more common causes. This article reviews the literature regarding CRPS following TKA, explains the diagnosis, and discusses treatment. [Orthopedics. 2020;4x(x):xx-xx.].

Orthopedic implant device sales representatives ("reps") can provide intraoperative guidance based on their product knowledge, as part of their many responsibilities. However, for experienced high-volume arthroplasty surgeons, a representative may not be required in the room for most primary total knee arthroplasty (TKA) procedures. The goal of this study was to describe the authors' experience with a modified rep model for primary TKA. Between January and December 2017, a total of 100 unilateral primary TKAs were performed with a modified rep model and compared with 100 primary TKAs that were performed before this protocol. The authors adopted 2 additional initiatives to institute this protocol safely: (1) improved education of operating room staff and allocation of responsibilities; and (2) reengineering of the existing surgical trays. No perioperative complications, including readmission, periprosthetic fracture, or infection, occurred in either group. In addition, no difference was found in mean length of stay between the modified rep and conventional cohorts (2.2 and 2.4 days, respectively; P=.49). Mean operating room time was less with the modified rep cohort (102.1 vs 117.8 minutes; P<.001), as was total instrument turnover time in the operating room (13.9 vs 29.7 minutes; P<.0001) and in central sterilization (59.4 vs 126.8 minutes; P<.001). No errors occurred with implant accuracy or trays, and there was no need to change the type of implant with the modified rep model, compared with 6% of trays requiring additional sterilization with the conventional model. The negotiated implant cost with the modified rep model was approximately $2000 less than that for the conventional group. This study found that the modified rep model for primary TKA is safe and has the potential for substantial cost savings. [Orthopedics. 202x;4x(x):xx-xx.].

Electronic health record (EHR) technologies have improved the ease of access to structured clinical data. The standard means by which data are collected continues to be manual chart review. The authors compared the accuracy of manual chart review against modern electronic data warehouse queries. A manual chart review of the EHR was performed with medical record numbers and surgical admission dates for the 100 most recent inpatient venous thromboembolic events after total joint arthroplasty. A separate data query was performed with the authors' electronic data warehouse. Data sets were then algorithmically compared to check for matches. Discrepancies between data sets were evaluated to categorize errors as random vs systematic. From 100 unique patient encounters, 27 variables were retrieved. The average transcription error rate was 9.19% (SD, ±5.74%) per patient encounter and 11.04% (SD, ±21.40%) per data variable. The systematic error rate was 7.41% (2 of 27). When systematic errors were excluded, the random error rate was 5.79% (SD, ±7.04%) per patient encounter and 5.44% (SD, ±5.63%) per data variable. Total time and average time for manual data collection per patient were 915 minutes and 10.3±3.89 minutes, respectively. Data collection time for the entire electronic query was 58 seconds. With an error rate of 10%, manual chart review studies may be more prone to type I and II errors. Computer-based data queries can improve the speed, reliability, reproducibility, and scalability of data retrieval and allow hospitals to make more data-driven decisions. [Orthopedics. 2020;43(x):xx-xx.].

INTRODUCTION/BACKGROUND:Hip dislocation is a devastating complication after total hip arthroplasty (THA), which is slightly higher when using the traditional posterior approach. The piriformis tendon is the most important dynamic posterior stabilizing structure. The piriformis-sparing technique provides a reproducible method for THA, greatly reducing the dislocation rate. MATERIALS AND METHODS/METHODS:After exposure and identifying piriformis, the inferior border of the piriformis is released from the short rotators and capsule with a BOVIE® (Symmetry Surgical, Inc, Nashville, Tennessee). This dissection is continued to the lesser trochanter as one sleeve and then tagged. The anterior/inferior capsule is released with a BOVIE® from the femur to aid in acetabular exposure. The femur is roughly placed in 30° of adduction, 70° of flexion, and slight internal rotation. An anterior retractor is used to displace the proximal femur anteriorly and superiorly. The reamer is placed inside the acetabulum through the inferior approach. Next, the acetabulum is progressively reamed to the appropriate size and depth, and the final component is placed in proper anteversion and abduction angles based on preoperative functional assessment. After insertion of final components and final hip reduction, the interval beneath the piriformis tendon and superior portion of the capsule is repaired with ETHIBOND® sutures (Johnson & Johnson Inc., New Brunswick, New Jersey). Then, two tunnels in the proximal femur with a 2.7mm drill bit is made and posterior capsule and short rotators are secured through these tunnels. RESULTS:This technique was used in 150 THAs with a minimum follow up of six months and a mean of 1.2 years ± 1.5 years. There was no dislocation at final follow up. The mean anteversion and abduction was 23 ± 2.7 and 42 ± 3.1, respectively. CONCLUSION/CONCLUSIONS:Preserving the piriformis tendon may cause less visualization of the superior portion of the acetabulum. However, the anterior/inferior capsular release, and proper placement of the femur with flexion, internal rotation, and adduction, makes it possible to achieve highly reproducible results.

INTRODUCTION/BACKGROUND:Choice of articulating spacer in selected Methicillin-resistant Staphylococcus aureus (MRSA) patients with instability that do not qualify for a second-stage revision (i.e., due to significant co-morbidities, multiple persistent infections, open wound ulcers) is challenging. To avoid a recurrent biofilm when using a cruciate-retaining (Cr/Cb) femoral implant, we have utilized a polymer femoral implant and constraint all-polyethylene (all-poly) tibia with stem extensions as a permanent spacer. MATERIALS AND METHODS/METHODS:After removal of prior implants and final debridement, appropriate-sized trial femur and proper thickness all-poly tibia are selected. Two chest tubes are loaded with cement with a delivery gun to make the extension rods. A Steinmann pin is inserted into the stem of the tibial insert. The components are inserted and the knee is reduced, then flexion and extension gaps are assessed. Small adjustments can be made to fill the gaps with extra cement. If there is collateral insufficiency, a constrained polyethylene (poly) can be used with the extension rod. An appropriate antibiotic is used based on the final culture, sensitivity, and availability in powder form. RESULTS:This technique has been performed on 32 MRSA prosthetic joint infection (PJI) cases, followed for a minimum of nine months (nine months to three years). The mean final range of motion was 70 ± 15 degrees (30-110 degrees). Final radiographs do not show any sign of subsidence, loosening, or failure of the spacer. Rate of eradication of infection was 97% in the remaining 31 cases. One patient required amputation due to lack of wound coverage. CONCLUSION/CONCLUSIONS:Custom-made articulating spacer using all-poly tibia and a trial femur with stem extension can provide reproducible outcomes in treating PJI while maintaining mobility.

Background: Proper positioning of the acetabular cup deters dislocation after total hip arthroplasty (THA) and is therefore a key focus for orthopaedic surgeons. The concept of a safe zone for acetabular component placement remains widely utilized in contemporary THA practice; however, components positioned in this safe zone still dislocate. The purpose of this study was to characterize trends in acetabular cup positioning and to determine if the surgical approaches used affected the rate at which the components were placed in the safe zones. Methods: This retrospective, observational study reviewed acetabular cup position in 1,236 patients who underwent THA using computer-assisted navigation. Outcomes included acetabular cup position measurements derived from a surgical navigation device and surgical approach. Results: The overall mean cup position of all recorded cases was 21.8 degrees (±7.7 degrees, 95% CI=6.7 degrees, 36.9 degrees) of anteversion and 40.9 degrees (±6.5 degrees, 95% CI=28.1 degrees, 53.7 degrees) of inclination. For anteversion and inclination, 65.5% (809/1236) of acetabular cup components were within the Lewinnek safe zone, and 58.4% (722/1236) were within the Callanan safe zone. Acetabular cups were placed at a mean of 6.8 degrees of anteversion (posterior/lateral approach: 7.0 degrees, anterior approach: 5.6 degrees) higher than the Lewinnek and Callanan safe zones, whereas inclination was positioned 0.9 degrees higher than the reported Lewinnek safe zone and 3.4 degrees higher than the Callanan safe zone. Conclusions: Our data show that while most acetabular cups were placed within the traditional safe zones, the mean anteversion orientation is considerably higher than those suggested by the Lewinnek and Callanan safe zones. The implications of this observation warrant further investigation. Level of Evidence: Level III.

This study compared the postoperative analgesic efficacy of liposomal bupivacaine as a single-administration adductor canal block (ACB) vs periarticular injection (PAI) for pain control after total knee arthroplasty (TKA). From May 2016 to June 2017, a total of 70 unilateral TKA patients were randomized into 2 groups: PAI (extended-release bupivacaine 266 mg [20-mL vial] with 20 mL of 0.5% bupivacaine hydrochloride and normal saline to a total volume of 120 mL) and ACB (subsartorial saphenous nerve using extended-release bupivacaine 266 mg [20-mL vial]). All patents underwent spinal anesthesia with comprehensive preemptive and postoperative multi-modal pain protocol. All opioids administered were converted to morphine equivalents. Pain was recorded at 4 to 12 hours on the day of surgery, and on postoperative days 1, 2, and 3. Patients and investigators other than the surgeon and anesthesiologist were blinded to the study. The difference in pain scores between the PAI and ACB groups was not statistically significant during the first 12 hours (day 0) after surgery or on postoperative day 1 (5.31 vs 4.26, P=.091). However, on postoperative day 3, the mean pain score increased in the ACB group and decreased in the PAI group (4.8 vs 1.83, P=.037). There was no statistically significant difference between the 2 groups regarding the accumulative daily converted morphine equivalent consumption or total consumption. Although the PAI group demonstrated longer lasting pain relief than the ACB group for the duration of the study, other outcomes were similar between the 2 groups. [Orthopedics. 202x; xx(x):xx-xx.].

Arthrofibrosis is the pathologic stiffening of a joint caused by an exaggerated inflammatory response. As a common complication following total knee arthroplasty (TKA), this benign-appearing connective tissue hyperplasia can cause significant disability among patients because the concomitant knee pain and restricted range of motion severely hinder postoperative rehabilitation, clinical outcomes, and basic activities of daily living. The most effective management for arthrofibrosis in the setting of TKA is prevention, including preoperative patient education programs, aggressive postoperative physical therapy regimens, and anti-inflammatory medications. Operative treatments include manipulation under anesthesia, arthroscopic debridement, and quadricepsplasty.