Faculty Bibliography

Tourniquet use creates a reduced blood surgical field during total knee arthroplasty (TKA), however, prolonged ischemia may cause postoperative tourniquet complications. To understand the effects of tourniquet-induced ischemia, we performed a prospective observational study using quantitative broadband diffuse optical spectroscopy (DOS) to measure tissue hemodynamics and water and lipid concentrations before, during, and after tourniquet placement in subjects undergoing TKA. Data was collected for 6 months and, of the total subjects analyzed (n = 24), 22 were primary TKAs and 2 were revision TKA cases. We specifically investigated tourniquet-induced hemodynamics based upon subject-specific tissue composition and observed a significant relationship between the linear rate of deoxygenation after tourniquet inflation and water/lipid ratio (W/L, p < 0.0001) and baseline somatic tissue oxygen saturation, StO₂ (p = 0.05). Subjects with a low W/L ratio exhibited a lower tissue metabolic rate of oxygen consumption, (tMRO₂ ) (p = 0.008). Changes in deoxyhemoglobin [HbR] (p = 0.009) and lipid fraction (p = 0.001) were significantly different between high and low W/L subject groups during deoxygenation. No significant differences were observed for hemodynamics during reperfusion and total tourniquet time was neither significantly related to the hemodynamic hyperemic response (p = 0.73) nor the time to max StO₂ after tourniquet release (p = 0.57). In conclusion, we demonstrate that DOS is capable of real-time monitoring of tissue hemodynamics distal to the tourniquet during TKA, and that tissue composition should be considered. DOS may help surgeons stratify hemodynamics based upon tissue composition and eventually aid the preoperative risk assessment of vascular occlusions from tourniquet use during TKA.

Non-English-speaking patients face increased communication barriers when undergoing total joint arthroplasty (TJA). Surgeons may learn or have proficiency in languages spoken among their patients to improve communication. This study investigated the effect of surgeon-patient language concordance on outcomes after TJA. We conducted a single-institution, retrospective review of patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) whose preferred language was not English. Patients were stratified based on whether their surgeon spoke their preferred language (language concordant [LC]) or not (language discordant [LD]). Baseline characteristics, length of stay, discharge disposition, revision rate, readmission rate, and patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS, JR], Hip disability and Osteoarthritis Outcome Score for Joint Replacement [HOOS, JR], and Patient-Reported Outcomes Measurement Information System [PROMIS]) were compared. A total of 3390 patients met inclusion criteria, with 855 receiving THA and 2535 receiving TKA. Among patients receiving THA, 440 (51.5%) saw a LC provider and 415 (48.5%) saw a LD provider. Those in the LC group had higher HOOS, JR scores at 1 year postoperatively (67.4 vs 49.3, P=.003) and were more likely to be discharged home (77.5% vs 69.9%, P=.013). Among patients receiving TKA, 1051 (41.5%) received LC care, whereas 1484 (58.5%) received LD care. There were no differences in outcome between the LC and LD TKA groups. Patients receiving THA with surgeons who spoke their language had improved patient-reported outcomes and were more commonly discharged home after surgery. Language concordance did not change outcomes in TKA. Optimizing language concordance for patients receiving TJA may improve postoperative outcomes. [Orthopedics. 2023;46(6):334-339.].

Accurate and reproducible acetabular component positioning is among the most important technical factors affecting outcomes of total hip arthroplasty. Although several studies have investigated the influence of pelvic tilt and obliquity on functional acetabular anteversion, the effect of pelvic axial rotation has not yet been established. We analyzed a generic simulated pelvis created using preoperative full-body standing and sitting radiographs. A virtual acetabulum was placed in 144 different scenarios of acetabular anteversion and abduction angles. In each scenario, the effects of pelvic tilt and pelvic axial rotation on different combinations of acetabular orientations were assessed. The change in acetabular anteversion was 0.75° for each 1° of pelvic tilt and was most linear in abduction angles of 40°±45°. The change in acetabular anteversion was 0.8° for each 1° of pelvic axial rotation. Surgeons may consider adjusting acetabular anteversion in fixed axial pelvic deformities when the degree of deformity affects functional acetabular positioning, assessed from preoperative standing and sitting weight-bearing radiographs. [Orthopedics. 2023;46(1):e27-e30.].

INTRODUCTION/UNASSIGNED:With the increasing demand for total knee arthroplasty (TKA) and the burden of revision TKA on the healthcare system, as well as the quality of life implications for patients, it is extremely important for surgeons to be able to anticipate and prevent TKA mechanical complications. Surgeons must be familiar with the different causes and mechanisms of TKA complications so that they can properly treat patients with failed TKAs and better avoid these complications. AREAS COVERED/UNASSIGNED:This review addresses TKA mechanical complications and provides context for the topic. A detailed review of surgical factors, implant factors, and patient factors that contribute to mechanical complications after TKA is provided. All of the literature cited in this review was gathered from the PubMed online database using different keywords based on the section of the manuscript. EXPERT OPINION/UNASSIGNED:As surgeons and engineers solve certain issues in TKA, new challenges will inevitably arise. We must continue to push forward and innovate from both a surgical technique and implant design perspective.

BACKGROUND/UNASSIGNED:. Of the 38 patients, 1 (2.6%) experienced a postoperative dislocation that was subsequently treated with closed reduction without further dislocation. This surgical technique represents a favorable surgical option for patients with acetabular bone loss who are at risk for hip instability. In the example case described in the present video article, the patients had a history of dislocations, lumbar fusion, and evidence of Paprosky 3B acetabular defect; as such, the decision was made to revise to a porous shell and cement a monoblock dual-mobility implant. DESCRIPTION/UNASSIGNED:With use of the surgeon's preferred approach, the soft tissue is dissected and the hip is aspirated. The hip is dislocated and a subgluteal pocket is made with use of electrocautery to mobilize the trunnion of the femoral stem to aid in acetabular exposure. The femoral component is assessed to ensure appropriate positioning with adequate anteversion. The acetabular component and any acetabular screws are removed. A "ream to fit" technique is performed in the acetabulum until bleeding bone is encountered, with minimal reaming performed in healthy bone from the posterior column. A trial prosthesis is placed within the acetabulum to evaluate if there is satisfactory fixation and if any augment is necessary. Care must be taken during reaming to ensure that enough bone is reamed to accommodate a porous shell that can fit the monoblock dual-mobility implant with a 2-mm cement mantle. Smaller porous shells measuring 56 mm are available for smaller defects but are often not utilized in cases of substantial acetabular bone loss. Fresh-frozen cancellous allograft is utilized to fill any contained defects. The revision porous shell with circumferential screw holes is utilized to allow for screw fixation posterosuperior and anterior toward the pubis. The implants are dried prior to placement of the cement. The cement is applied to the shell and the monoblock dual-mobility implant to ensure adequate coverage. Antibiotic-loaded cement can be utilized according to surgeon preference. Excess cement is removed under direct visualization while the cement is drying, and the position of the dual-mobility implant is adjusted in approximately 20° anteversion and 40° inclination. Stability is assessed after the cement cures, and intraoperative radiography can be performed to confirm cup positioning prior to closure. Any remaining capsule is closed, followed by closure of the remaining soft tissue in a layered fashion. ALTERNATIVES/UNASSIGNED:A fully porous multi-hole jumbo cup with conventional polyethylene liner and femoral head can be utilized to increase the jump distance of the femoral head. Constrained, lipped, or offset polyethylene liners can be utilized if the shell is well fixed and a dual-mobility implant cannot be inserted. A cemented dual-mobility implant can be utilized in a well-fixed acetabular shell without evidence of loosening or osteolysis. RATIONALE/UNASSIGNED:. Moreover, acetabular cup survival was excellent, with 100% survival at 1 year and 96.2% at 2 years. EXPECTED OUTCOMES/UNASSIGNED:. IMPORTANT TIPS/UNASSIGNED:In order to allow for circumferential coverage for fixation and ingrowth potential in cases with acetabular defects, the shell is typically impacted slightly vertical (45° to 50° of inclination) and in neutral version (0° to 5° of anteversion). Positioning can be adjusted to improve osseous contact and ingrowth as determined by the size and shape of the defect.The use of a drill guide for the locking screws allows limited degrees of variable screw angulation. In the revision setting, longer screws may be placed posterosuperior toward the sciatic notch or anteroinferior into the pubis. Surgeons should be aware of the anatomy and should predrill holes to reduce the risk of injury to surrounding neurovascular structures such as the obturator artery anteriorly.Any screw holes that are not filled should be covered with plastic hole covers in order to prevent cement from migrating behind the cup. Implants should be dried prior to the placement of the cement, and the cement should be applied to the shell and the dual-mobility implant to ensure adequate coverage.Utilize a monoblock dual-mobility implant that is designed for cementation in order to avoid implant dissociation from the acetabular shell.Remove all fibrous tissue that may hinder bony integration.Assess for pelvis discontinuity; pelvis discontinuity and acetabular bone loss are risk factors in the setting of any revision and should be properly assessed preoperatively and intraoperatively and managed accordingly.Avoid over-reaming and damage of the posterior column.Utilize a reamer or trial to assess defect size and need for augments.Place a compression screw where the cup is in contact with the bone in order to avoid tilting.Cover unused screw holes. ACRONYMS AND ABBREVIATIONS/UNASSIGNED:THA = total hip arthroplastyS/P = status postTKA = total knee arthroplastyCT = computed tomographyKM = Kaplan MeierDMC = dual-mobility cupPE = polyethylene.

BACKGROUND:It is unclear howmetal augments,polyethylene (PE) liner thickness, and length of cemented stemcontribute to load transferwhen reconstructing uncontained tibial metaphyseal bone loss of Anderson Orthopedic Research Institute (AORI) Type II defects during revision total knee arthroplasty (rTKA).The aimof this study is to understand the impact of these three variableson load transfer through the tibial baseplate. For a fixed defect depth, we hypothesized that there is a particular combination of liner and augment thickness and stem length that minimizes bone stress, reducing the risk of aseptic loosening. METHODS:We conducted a finite element analysis (FEA) to model stresses at the bone-cement interface with different iterations of metal augments, PE liner thicknesses andfully-cemented stems lengths. RESULTS:For a 20 mm tibial defect, constructs with thicker metal augments and thinner polyethylene liners were superior. Constructswith a fully cemented stem further reduced bone stress on the tibial plateau. Bone stress was lowest when a 100 mm fully-cemented stem was used, while stems between 30 mm - 80 mm produced similar results. CONCLUSIONS:When addressing a tibial bone defect of AORI Type II in rTKA, our FEA model demonstrates that surgeons should opt to use the thickest metal augments in combination with afully-cemented stem with an added length of at least 30 mm, which allows for surgical flexibility together with the most stable construct.Our study is notably limited by lack of modeling of knee joint moments, which are important when considering micromotion, bone-implant interface and stem effectiveness.

INTRODUCTION/BACKGROUND:A novel fully porous acetabular titanium shell has been designed to reduce stiffness mismatch between bone and implant and promote osseointegration in complex (cTHA) and revision total hip arthroplasty (rTHA). A highly cross-linked polyethylene (XLPE) liner is cemented within the cup to reduce wear rates and increase survivorship. This study reported the outcomes of an XLPE liner cemented into a novel 3D-printed fully porous cup in cTHA and rTHA. METHODS:Presented was a multicenter retrospective review of 40 patients (6 cTHA and 34 rTHA) who underwent THA with a fully porous titanium acetabular cup and cemented XLPE liner. Data were collected on demographics, surgical information, outcomes, including osseointegration and migration and implant survivorship. RESULTS:) and were followed up for a mean time of 2.21 ± 0.77 years. Six patients underwent cTHA and 34 patients underwent rTHA. The mean hospital length of stay was 5.34 ± 3.34 days. Three (7.5%) 90-day readmissions were noted. Harris Hip Scores improved, on average, from 53.87 ± 12.58 preoperatively to 83.53 ± 12.15 postoperatively (P<0.001). One case of acetabular shell aspetic loosening with migration was noted. Thirty-nine of the 40 acetabular components were fully osseointegrated without migration. Two patients underwent re-revision surgery for PJI and one patient received acetabular shell+liner re-revision due to aseptic loosening. Kaplan-Meier analysis showed an all-cause revision-free survival rate of 95.0% at 6 months and 1 year, and 92.0% at 4-years. Aseptic acetabular cup, liner dislocation/loosening, and fracture-free survival was 100% at 6 months and 1-year, and 97.1% at 2 years. CONCLUSION/CONCLUSIONS:The combined use of a novel 3D-printed fully porous titanium acetabular shell and cemented XLPE acetabular liner yielded excellent rates of osseointegration, and all-cause and acetabular aseptic loosening survivorship at a minimum 1-year follow-up. Further long-term studies are needed to assess the longevity of this construct.

BACKGROUND:Isolated head and liner exchange is an appealing alternative to a more extensive revision total hip arthroplasty in patients who have well-fixed components. Despite efforts to increase femoral offset and restore soft tissue tensioning, limited component revision may be associated with higher rates of postoperative instability. METHODS:(range, 18.2-46.7). The most common indications for surgery included acetabular liner wear in 86 hips (41%), instability in 40 hips (19%), and infection in 36 hips (17%). RESULTS:increase, 95% CI 0.80-0.99, P = .046). CONCLUSION/CONCLUSIONS:In a large cohort of patients who had isolated head and liner exchange, patients who had prior instability had 7-fold elevated odds of postoperative dislocation. This risk remains significant after controlling for cup positioning outside the Lewinnek safe zone, liner type, head size, neck length, soft tissue compromise, neuromuscular disease, and dual mobility constructs. LEVEL OF EVIDENCE/METHODS:III, retrospective cohort study.

BACKGROUND:Demographic variables play an important role in outcomes following revision total hip arthroplasty (rTHA). Surgical and in-patient variables as well as outcomes vary between indications for rTHA. The purpose of this study was to investigate the impact of the indication for the rTHA on costs and postoperative outcomes. METHODS:This retrospective cohort analysis investigated all patients who underwent unilateral, aseptic rTHA at an academic orthopaedic specialty hospital who had at least 1-year postoperative follow-up. In total, 654 patients were evaluated and categorized based on their indication for aseptic rTHA. Demographics, direct and total procedure costs, surgical factors, postoperative outcomes, and re-revision rates were collected and compared between indications. RESULTS:Younger patients had the greatest leg length discrepancy (LLD) and older patients had the highest incidence of periprosthetic fracture (PPF) (P = .001). The greatest proportion of full revisions were found for LLD (16.7%) and head/polyethylene liner-only revisions for metallosis/adverse tissue reaction (100%). Operative time was significantly longest for LLD revisions and shortest for metallosis/adverse tissue reaction revisions (P < .001). Length of stay was longest for periprosthetic fracture and shortest for LLD and stiffness/heterotopic ossification (P < .001). Re-revision rate was greatest for implant failure and lowest for LLD. Total cost was highest for PPF (148.9%) and lowest for polyethylene liner wear (87.7%). CONCLUSIONS:Patients undergoing rTHA for indications such as PPF and aseptic loosening were associated with longer operative times, length of stay and higher total and direct costs. Therefore, they may need increased perioperative attention with respect to resource utilization, risk stratification, surgical planning, and cost-reducing measures. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.

INTRODUCTION/BACKGROUND:Spinal anesthesia (SA) is the preferred method of anesthesia at many centers for total joint arthro- plasty (TJA). However, a small subset of patients fails SA, necessitating a conversion to general anesthesia (GA). This report assesses the patient characteristics associated with failed SA. METHODS:A retrospective study was conducted on patients who underwent SA during their primary TJA between Janu- ary 2015 and December 2016 at our institution. A subset of this group required a conversion from SA to GA. Anesthesia reports were reviewed for the number of attempts at SA and the documented reason for failure. The SA failure cohort was then subdivided into failure categories based on the reasons that had been provided. RESULTS:A total of 5,706 patients were included in this study, 78 of which experienced SA failure. The number of attempts was most strongly associated with SA failure, with three attempts resulting in a five times increased failure rate (OR = 4.73, p = 0.010) and four attempts resulting in 12 times increased failure rate compared to the no failure cohort (OR = 12.3, p < 0.001). Greater than two attempts occurred in 87.5% of the "technical failure" sub-group of the SA failure cohort (p < 0.001). No difference was demon- strated among the other patient characteristics, such as age, sex, body mass index, race, American Society of Anesthesia (ASA) score, and surgical time. CONCLUSIONS:The results suggest that the major predic- tor influencing spinal to general anesthesia conversion was the number of attempts at SA, especially among technical failure cases. Based on the results, it may be appropriate for anesthesiologists to convert to GA after two failed spi- nal attempts. Further studies are warranted to assess this relationship for firm clinical recommendations.