Alignment is only part of the equation: High variability in soft tissue distractibility in the varus knee undergoing primary TKA.

PURPOSE: The purpose of this study is to evaluate the in vivo medial and lateral joint laxities across various total knee arthroplasty (TKA) alignment categories correlated to (1) hip-knee-ankle angle, (2) proximal tibial angle and (3) distal femoral angle in a consecutive group of patients undergoing robotic-assisted TKA. METHODS: Using ligament tensions acquired during 805 robotic-assisted TKA with a dynamic ligament tensor under a load of 70-90 N, the relationship between medial and lateral collateral ligament laxity and overall limb alignment was established. Only knees with neutral or mechanical varus alignment were included and divided into five groups: neutral (0°-3°), varus 3°-5°, varus 6°-9°, varus 10°-13° and varus ≥14°. Groups were further subdivided by the intraoperative medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). The distraction of the medial and lateral sides was compared across the various alignments using an analysis of variance. RESULTS: The ability to distract the medial collateral ligament in extension and flexion was proportional to the degree of varus deformity, increasing from 4.0 ± 2.3 mm in the neutral group to 8.7 ± 3.2 mm in the varus ≥14° group (p < 0.0001). On the lateral side, the distraction of the lateral collateral ligament decreased in both extension (2.2 ± 2.4 vs. 1.2 ± 2.7, p < 0.0001) and flexion (2.8 ± 2.8 to 1.7 ± 3.0, p < 0.0001) with increasing native varus deformity. MPTA and LDFA had similar effects, where increasing MPTA varus and LDFA valgus increased medial distractibility in extension and flexion. There was significant variability of the stretch of the ligaments within and across all alignment categories, in which the standard deviation of the groups ranged from 2.0 to 3.0 mm. CONCLUSION: This study demonstrates increased medial ligament distractibility with increasing varus deformity. However, there was significant variability in ligamentous laxity within various limb alignment categories suggesting the anatomy and soft tissue identity of the knee is complex and highly variable. TKAs seeking to be more anatomic will not only need to restore alignment but also native soft tissue tensions. LEVEL OF EVIDENCE: Level III, prognostic.

No Benefit to Sensor-guided Balancing Compared With Freehand Balancing in TKA: A Randomized Controlled Trial.

BACKGROUND: Soft tissue balancing in TKA has traditionally relied on surgeons' subjective tactile feedback. Although sensor-guided balancing devices have been proposed to provide more objective feedback, it is unclear whether their use improves patient outcomes. QUESTIONS/PURPOSES: We conducted a randomized controlled trial (RCT) comparing freehand balancing with the use of a sensor-guided balancing device and evaluated (1) knee ROM, (2) patient-reported outcome measures (PROMs) (SF-12, WOMAC, and Knee Society Functional Scores [KSFS]), and (3) various surgical and hospital parameters (such as operative time, length of stay [LOS], and surgical complications) at a minimum of 2 years of follow-up. METHODS: A total of 152 patients scheduled for primary TKA were recruited and provided informed consent to participate in this this study. Of these, 22 patients were excluded preoperatively, intraoperatively, or postoperatively due to patient request, surgery cancellation, anatomical exclusion criteria determined during surgery, technical issues with the sensor device, or loss to follow-up. After the minimum 2-year follow-up was accounted for, there were 63 sensor-guided and 67 freehand patients, for a total of 130 patients undergoing primary TKA for osteoarthritis. The procedures were performed by one of three fellowship-trained arthroplasty surgeons (RPS, HJC, JAG) and were randomized to either soft tissue balancing via a freehand technique or with a sensor-guided balancing device at one institution from December 2017 to December 2018. There was no difference in the mean age (72 ± 8 years versus 70 ± 9 years, mean difference 2; p = 0.11), BMI (30 ± 6 kg/m 2 versus 29 ± 6 kg/m 2 , mean difference 1; p = 0.83), gender (79% women versus 70% women; p = 0.22), and American Society of Anesthesiology score (2 ± 1 versus 2 ± 1, mean difference 0; p = 0.92) between the sensor-guided and freehand groups, respectively. For both groups, soft tissue balancing was performed after all bony cuts were completed and trial components inserted, with the primary difference in technique being the ability to quantify the intercompartmental balance using the trial tibial insert embedded with a wireless sensor in the sensor-guided cohort. Implant manufacturers were not standardized. Primary outcomes were knee ROM and PROMs at 3 months, 1 year, and 2 years. Secondary outcomes included pain level evaluated by the VAS, opioid consumption, inpatient physical therapy performance, LOS, discharge disposition, surgical complications, and reoperations. RESULTS: There was no difference in the mean knee ROM at 3 months, 1 year, and 2 years postoperatively between the sensor-guided cohort (113° ± 11°, 119° ± 13°, and 116° ± 12°, respectively) and the freehand cohort (116° ± 13° [p = 0.36], 117° ± 13° [p = 0.41], and 117° ± 12° [p = 0.87], respectively). There was no difference in SF-12 physical, SF-12 mental, WOMAC pain, WOMAC stiffness, WOMAC function, and KSFS scores between the cohorts at 3 months, 1 year, and 2 years postoperatively. The mean operative time in the sensor-guided cohort was longer than that in the freehand cohort (107 ± 0.02 versus 84 ± 0.04 minutes, mean difference = 23 minutes; p = 0.008), but there were no differences in LOS, physical therapy performance, VAS pain scores, opioid consumption, discharge disposition, surgical complications, or percentages of patients in each group who underwent reoperation. CONCLUSION: This RCT demonstrated that at 2 years postoperatively, the use of a sensor-balancing device for soft tissue balancing in TKA did not confer any additional benefit in terms of knee ROM, PROMs, and clinical outcomes. Given the significantly increased operative time and costs associated with the use of a sensor-balancing device, we recommend against its routine use in clinical practice by experienced surgeons. LEVEL OF EVIDENCE: Level I, therapeutic study.

Aspirin Is Safe for Venous Thromboembolism Prophylaxis for Patients With a History of Gastrointestinal Issues.

BACKGROUND: The safety of acetylsalicylic acid (ASA, aspirin) in patients with prior history of gastroesophageal reflux or peptic ulcer disease remains unclear. The purpose of this study was to determine the safety of ASA for venous thromboembolism (VTE) prophylaxis after total joint arthroplasty in patients with prior history of gastrointestinal (GI) issues. METHODS: This was an institutional, retrospective cohort study of 19,044 patients who underwent primary total hip and total knee arthroplasty from 2013 to 2019. We divided the patients into two cohorts based on the presence or absence of pre-existing GI issues. Patient demographics, VTE prophylaxis, and postoperative complications were collected. The primary outcome measure was GI bleed. RESULTS: In our series, 3090 patients had a preoperative GI issue and 15,954 did not have a GI issue. ASA was the most common mode of VTE prophylaxis (89%), followed by Coumadin (4.7%), direct oralanticoagulants (4.2%), low-molecular-weight heparin (1.7%), and others (0.4%). In the cohort of patients given ASA, there was no significant difference in postoperative GI bleeding between those with (2/1781, 0.11%) and without preoperative GI issues (8/7,628, 0.10%, P = 1.0). In the overall cohort, history of preoperative GI issues was associated with an increased risk of postoperative GI bleeding (0.32% vs 0.11%, P = .031). In logistic regression analysis, ASA was associated with a protective effect against GI bleed (OR = 0.09, 95% CI 0.01-0.40, P = .003). CONCLUSION: ASA is safe for VTE prophylaxis after total joint arthroplasty in patients with history of GI issues and is not associated with an increased risk of postoperative GI bleeds.

Characterizing Femoral and Acetabular Bone Loss in Two-Stage Revision Total Hip Arthroplasty for Infection.

BACKGROUND: The process of infection and multiple procedure-related factors in 2-stage exchange arthroplasty may lead to severe bone loss that can complicate subsequent reimplantation. The primary purpose of this study is to quantitatively characterize the extent of bone loss on the femoral and acetabular side prior to reimplantation during 2-stage revision hip arthroplasty for infection. METHODS: This retrospective case series includes 47 patients with planned 2-stage exchange arthroplasty for treatment of infected total hip replacement. Demographic, clinical, and surgical information, and complications during the 2-stage process were collected on all patients. The radiographs of all patients were reviewed prior to first-stage explantation and post-reimplantation or latest follow-up to characterize bone loss using the Paprosky classification systems. RESULTS: Of the 47 patients with planned 2-stage exchange, 10 patients (21%) were not reimplanted. Following explant and spacer placement, 32 patients (68%) experienced progressive femoral bone loss, and 20 (43%) experienced progressive acetabular bone loss. Patients who experienced progression of both femoral and acetabular bone (14, 30%) had a longer time between resection and reimplantation (164 ± 128 vs 88 ± 26 days, P = .03). A reimplantation time of greater than 90 days was associated with an increased risk of combined bone loss progression (15% vs 53%, P = .01). For patients who underwent reimplantation (79%), increased bone loss led to high rates of diaphyseal femoral fixation (97%) and revision acetabular components (38%). CONCLUSION: Increased time to reimplantation in 2-stage exchange arthroplasty for prosthetic hip infections is associated with a high rate of acetabular and femoral bone loss, and increased complexity of reimplantation.

High Bundled Payment Costs Following Total Hip and Knee Arthroplasty in African Americans.

BACKGROUND: Concerns exist that minorities who utilize more resources in an episode-of-care following total hip (THA) and knee arthroplasty (TKA) may face difficulties with access to quality arthroplasty care in bundled payment programs. The purpose of this study is to determine if African American patients undergoing TKA or THA have higher episode-of-care costs compared to Caucasian patients. METHODS: We queried Medicare claims data for a consecutive series of 7310 primary TKA and THA patients at our institution from 2015 to 2018. We compared patient demographics, comorbidities, readmissions, and 90-day episode-of-care costs between African American and Caucasian patients. A multivariate regression analysis was performed to identify the independent effect of race on episode-of-care costs. RESULTS: Compared to Caucasians, African Americans were younger, but had higher rates of pulmonary disease and diabetes. African American patients had increased rates of discharge to a rehabilitation facility (20% vs 13%, P < .001), with higher subacute rehabilitation ($1909 vs $1284, P < .001), home health ($819 vs $698, P = .022), post-acute care ($5656 vs $4961, P = .008), and overall 90-day episode-of-care costs ($19,457 vs $18,694, P = .001). When controlling for confounding comorbidities, African American race was associated with higher episode-of-care costs of $440 (P < .001). CONCLUSION: African American patients have increased episode-of-care costs following THA and TKA when compared to Caucasian patients, mainly due to increased rates of home health and rehabilitation utilization. Further study is needed to identify social variables that can help reduce post-acute care resources and prevent reduction in access to arthroplasty care in bundled payment models.

African American Patients Have Improved Functional Gains and Comparable Clinical Outcomes to Caucasian Patients After Total Hip and Knee Arthroplasty.

BACKGROUND: With the increasing popularity of alternative payment models, minorities who use more postacute care resources may face difficulties with access to quality total hip arthroplasty (THA) and total knee arthroplasty (TKA) care. The purpose of this study is to compare differences in perioperative complications and functional outcomes between African American and Caucasian patients undergoing THA and TKA. METHODS: We reviewed a consecutive series of all primary THA and TKA patients at our institution from 2015 to 2018. Demographics, comorbidities, 90-day complications, readmissions, Veterans Rand 12-Item Health Survey (VR-12), Hip disability Osteoarthritis Outcome Score (HOOS), and Knee injury and Osteoarthritis Outcome Scores (KOOS) were compared between African American and Caucasian patients. A multivariate analysis was performed to control for confounding variables. RESULTS: Of the 5284 patients included in the study, 1041 were African American (24.5%). Although African American patients had lower preoperative HOOS/KOOS (33.5 vs 45.1, P < .001) and mental VR-12 scores (37.8 vs 51.5, P < .001) compared with Caucasian patients, there was no clinical difference at 1 year in HOOS/KOOS (50.2 vs 50.4), mental VR-12 (55.0 vs 52.6), or physical VR-12 scores (39.5 vs 39.8). When controlling for demographics and medical comorbidities, African American race was associated with increased rehabilitation facility discharge (odds ratio, 1.69; P < .001) but no difference in readmissions or complications. CONCLUSION: Although African American patients had lower preoperative functional scores, they made improved postoperative gains when compared with Caucasian patients. Although there was no difference in postoperative complications, further studies should assess social causes for the increase in rehabilitation utilization rates in minority patients.

What is the Level of Evidence Substantiating Commercial Payers' Coverage Policies for Total Joint Arthroplasty?

BACKGROUND: The prevalence of total joint arthroplasty (TJA) in the United States has drawn the attention of health care stakeholders. The payers have also used a variety of strategies to regulate the medical necessity of these procedures. The purpose of this study was to examine the level of evidence of the coverage policies being used by commercial payers in the United States. METHODS: The references of the coverage policies of four commercial insurance companies were reviewed for type of document, level of evidence, applicability to a TJA population, and success of nonoperative treatment in patients with severe degenerative joint disease. RESULTS: 282 documents were reviewed. 45.8% were primary journal articles, 14.2% were level I or II, 41.2% were applicable to patients who were candidates for TJA, and 9.9% discussed the success of nonoperative treatment in patients who would be candidates for TJA. CONCLUSION: Most of the references cited by commercial payers are of a lower level of scientific evidence and not applicable to patients considered to be candidates for TJA. This is relatively uniform across the reviewed payers. The dearth of high-quality literature cited by commercial payers reflects the lack of evidence and difficulty in conducting high level studies on the outcomes of nonoperative versus operative treatment for patients with severe, symptomatic osteoarthritis. Patients, surgeons, and payers would all benefit from such studies and we encourage professional societies to strive toward that end through multicenter collaboration.

Tibial cement mantle thickness is not affected by tourniquetless total knee arthroplasty when performed with tranexamic acid.

PURPOSE: Evidence exists that tourniquet use leads to increased cement penetration in total knee arthroplasty (TKA) due to decreased blood and fat in the bone during cementation. The use of tranexamic acid (TXA) has led to decreased blood loss and transfusion rates. The purpose of this study was to determine if the use of a tourniquet while utilising modern TXA protocols affects the tibial cement mantle penetration. METHODS: 140 patients who underwent primary TKA with and without a tourniquet (70 in each group) were retrospectively reviewed. All patients received a standard TXA protocol. The primary outcome measure was cumulative depth of cement mantle penetration of the tibial plateau on post-operative radiographs. Secondary outcome measures included post-operative change in haemoglobin and hematocrit levels, blood loss, and transfusion rates. RESULTS: There was no significant difference in age, sex, or pre-operative haemoglobin or hematocrit levels between groups. Tourniquet use resulted in significantly lower blood loss (100.0 mL versus 154.7 mL, p < 0.001), and significantly reduced drop in haemoglobin (1.8 g/dL vs 2.5 g/dL, p < 0.001) and hematocrit (5.7% vs 7.4%, p = 0.04) levels. However, depth of tibial cement mantle penetration did not differ between the tourniquet group (15.3 mm) and non-tourniquet group (15.0 mm, p value n.s.). No patient in either group required a blood transfusion. CONCLUSIONS: Tourniquet use in primary TKA results in decreased blood loss and less change in pre-operative vs post-operative haemoglobin and hematocrit levels. However, with the use of TXA, not using a tourniquet resulted in similar cement mantle penetration around the tibial component as with a tourniquet.

Personal Protective Equipment: Current Best Practices for Orthopedic Teams.

The coronavirus disease (COVID-19) pandemic caused by the severe acute respiratory syndrome (SARS-CoV-2) virus is challenging healthcare providers across the world. Current best practices for personal protective equipment (PPE) during this time are rapidly evolving and fluid due to the novel and acute nature of the pandemic and the dearth of high-level evidence. Routine infection control practices augmented by airborne precautions are paramount when treating the COVID-19-positive patient. Best practices for PPE use in patients who have unknown COVID-19 status are a highly charged and emotional issue. The variables to be considered include protection of patients and healthcare providers, accuracy and availability of testing, and responsible use of PPE resources. This article also explores the concerns of surgeons regarding possible transmission to their own family members as a result of caring for COVID-19 patients.

Risk Factors for Unplanned Admission to the Intensive Care Unit After Elective Total Joint Arthroplasty.

BACKGROUND: Despite improved surgical and anesthesia techniques, as well as advances in perioperative protocols, a number of patients undergoing total joint arthroplasty (TJA) are at risk of serious medical complications that require intensive care unit (ICU) admission. With the recent move toward performing TJA in ambulatory surgical centers and on an outpatient basis, it is important to recognize patients that may require intensive care in the postoperative period. This study aimed to identify risk factors for ICU admission following elective total hip (THA) and knee (TKA) arthroplasty. METHODS: We evaluated 12,342 THA procedures, with 132 ICU admissions, and 10,976 TKA procedures, with 114 ICU admissions from 2005 to 2017. Demographic, preoperative, and surgical variables were collected and compared between cohorts using both univariate and logistic regression analysis. RESULTS: For THA, logistic regression analysis demonstrated older age, bilateral procedure, revision surgery, increased Charlson comorbidity index, general anesthesia, increased estimated blood loss, decreased preoperative hemoglobin, and increased preoperative glucose level were independently associated factors for increased risk of ICU admission. For TKA, increased age, increased body mass index, bilateral procedure, revision surgery, increased Charlson comorbidity index, increased estimated blood loss, general anesthesia, and increased preoperative glucose were independently significantly associated with ICU admission. CONCLUSION: In this study, we identify a number of critical independent risk factors which may place patients at increased risk of ICU admission following THA and TKA. Identification of these risk factors may help surgeons safely select those TJA candidates appropriate for surgery at facilities that do not have ICUs readily available.

Surgeons' Preoperative Work Burden Has Increased Before Total Joint Arthroplasty: A Survey of AAHKS Members.

BACKGROUND: Implementation of rapid recovery protocols and value-based programs in total joint arthroplasty (TJA) has required changes in preoperative management, such as optimization, education, and coordination. This study aimed to quantify the work burden associated with preoperative TJA care. METHODS: Two web-based surveys were distributed to surgeon members of the American Association of Hip and Knee Surgeons. The first questionnaire (265 respondents) consisted of questions related to preoperative patient care in TJA and the associated work burden by orthopedic surgeons and their financially dependent health care providers. The second survey (561 respondents) consisted of questions related to relative change in preoperative patient care work burden since 2013. RESULTS: Greater than 98% of survey respondents reported providing some level of preoperative medical optimization to their patients. The mean amount of reported time spent by the surgeon and/or a qualified health care provider in preoperative activities not included in work captured in current procedural terminology or hospital billing codes was 153 minutes. The mean amount of reported time spent by ancillary clinical staff in preoperative activities was 177 minutes. Most surgeons reported an increase in work burden for total knee (86%) and total hip (87%) arthroplasty since 2013, with a large portion reporting a 20% or greater increase in work (knee 66%, hip 64%). CONCLUSION: To provide quality arthroplasty care with marked reductions in complication rates, lengths of stay, and readmissions, members of the American Association of Hip and Knee Surgeons report a substantial preoperative work burden that is not included in current coding metrics. Policy makers should account for this time in coding models to continue to promote pathway improvements.

The Effect of Preoperative Anemia on Complications After Total Hip Arthroplasty.

BACKGROUND: Current literature suggests that preoperative hematocrit levels may play an important role in determining risk for complications after total hip arthroplasty (THA). The purpose of this study was to determine the role of preoperative anemia status on 30-day complications after THA. METHODS: Using the National Surgical Quality Improvement Program registry from 2006 to 2016, we identified all patients who underwent primary THA. Patients were placed into 3 cohorts based on preoperative hematocrit levels (normal > 36% [N = 166,538], mild anemia 27%-36% [N = 13,214], and severe anemia <27% [N = 541]). Differences in 30-day postoperative medical complications and readmission rates were compared using bivariate and multivariate analyses. RESULTS: Multivariate logistic regression analysis identified mild anemia compared with normal hematocrit as a significant risk factor for total complications (OR: 1.46, P < .001), mortality (OR: 2.06, P < .001), renal complications (OR: 2.59, P < .001), respiratory complications (OR: 1.89, P < .001), sepsis (OR: 2.01, P < .001), wound infection (OR: 1.36, P < .001), and urinary tract infection (OR: 1.44, P < .001). Severe anemia was also risk factor, with a higher odds ratio, for total complications (OR: 1.99, P < .001). Both mild and severe anemia were significant risk factors for increased rates of perioperative blood transfusion (mild: OR, 4.04, severe: OR, 5.58), nonhome discharge (OR: 1.74, OR: 1.64), and unplanned hospital readmissions (OR: 1.42, OR: 1.66). CONCLUSION: Preoperative anemia is a significant risk for perioperative complications after primary THA. Even mild anemia can lead to significantly increased risks of mortality, medical complications, and unplanned hospital readmissions in THA. This study further supports the need for screening and preoperative intervention for patients in this at-risk group.

Early Morbidity but Not Mortality Increases With Surgery Delayed Greater Than 24 Hours in Patients With a Periprosthetic Fracture of the Hip.

BACKGROUND: Studies have identified a possible morbidity and mortality benefit with expedited time to surgery after a native hip fracture. This association after hip periprosthetic fractures (PPF) has been less clearly delineated. The purpose of this study is to assess the effect of time to surgery on rates of 30-day complications. METHODS: The National Surgical Quality Improvement Program registry was used to identify all patients who underwent surgical intervention for hip PPF between 2005 and 2016. Patients were stratified into 2 cohorts based on time from hospital admission to surgery, either ≤24 hours (expedited) or >24 hours (non-expedited). Thirty-day outcome variables were assessed using bivariate and multivariate analyses. RESULTS: We identified 857 patients undergoing surgical intervention for hip PPF, of whom 402 (46.9%) underwent expedited surgery and 455 (53.1%) underwent non-expedited surgery. Patients with non-expedited surgery had an average time to surgery of 2.4 days (range, 1-14 days). Multivariate analysis adjusting for differences in baseline patient characteristics revealed that patients with a non-expedited procedure had higher rates of overall complications (odds ratio [OR] = 1.72; P = .014), respiratory complications (OR = 4.15; P = .0029), urinary tract infections (OR = 2.77; P = .020), nonhome discharge (OR = 2.22; P < .001), and blood transfusions (OR = 1.86; P < .001). There was no statistical difference in mortality (P = .093). Patients with non-expedited surgery also had longer total and postoperative (+2.7 days; P < .001) length of stay. CONCLUSION: This study did not identify any statistical difference in mortality but found an association with increased postoperative complications and non-expedited surgery for PPF. Additional prospective studies may be warranted to identify the causative factors behind this association.

Hemiarthroplasty Conversion: A Comparison to Primary and Revision Total Hip Arthroplasty.

BACKGROUND: Arthroplasty is the standard of care for elderly patients with displaced femoral neck fractures, with viable options including hemiarthroplasty (HA) and total hip arthroplasty (THA). With time, HA may need to be converted to THA, but it is unclear whether this is more similar to primary or revision THA. We compare complication and revision rates between these groups within 90 days and 2 years postoperatively. METHODS: We retrospectively reviewed 3 cohorts of patients treated at our institution: primary, conversion, and revision THA. Outcomes studied included intraoperative data, postoperative complications, and revision rates. We analyzed the groups using both parametric (analysis of variance test) and nonparametric (chi-squared test) statistics. RESULTS: Operative time between primary THA (108.0 minutes), conversion HA (147.9 minutes), and revision THA (160.1 minutes) cohorts differed significantly (P = .011). Estimated blood loss was also different between primary THA (386 mL), conversion HA (587 mL), and revision THA cohorts (529 mL) (P = .011). At 2 years, major complication rates between primary THA (6.2%), conversion HA (11.7%), and revision THA (26.7%) cohorts also differed significantly (P = .003), as was the revision rate in the primary THA (4.6%), conversion HA (10.0%), and revision THA (18.3%) cohorts (P = .043). CONCLUSION: This is the first study to compare short-term and midterm complications between primary, conversion, and revision THA. We observed conversion HA had similar operative time and estimated blood loss to revision THA, which was significantly higher than primary THA. However, we found that conversion HA more closely resembled primary THA with respect to perioperative complications rates.

The Learning Curve by Operative Time for Soft Tissue Balancing in Total Knee Arthroplasty Using Electronic Sensor Technology.

BACKGROUND: Electronic sensor devices can provide an objective assessment of soft tissue balancing in total knee arthroplasty (TKA) which may potentially decrease postoperative pain. We aim to quantify the learning curve for operative time (OT) for this technology. METHODS: Consecutive TKA cases balanced with an electronic sensor balancing device by one senior surgeon from 2013 to 2017 were included in this study. The OT (in minutes) was analyzed using the cumulative sum analysis to evaluate the learning curve for this technology. Further analysis was done by splitting the 287 patients into 7 cohorts, 41 patients each. RESULTS: Two hundred eighty-seven patients balanced with sensor technology were available for analysis. The cumulative sum OT learning curve estimated that this technology's learning curve was 41 cases. This curve consisted of 2 phases: phase 1 which includes the first 41 cases and phase 2 which includes the remaining 246 patients. The mean OT for the first and last sensor-assisted cohorts was 120.4 and 108.9 minutes (P = .021). The mean OT for the first sensor-assisted cohort and the control cohort was 120.4 versus 109 minutes (P = .023). The mean OT for the last sensor-assisted cohort and the control cohort was 108.9 versus 109 minutes (P = .94). CONCLUSION: Our findings suggest that it takes approximately 41 cases of sensor-assisted TKA cases to achieve OTs identical to manually balanced TKA cases. This is a relatively shallow learning curve for the sensor technology, and allows arthroplasty surgeons to objectively achieve soft tissue balancing without adding OT to the surgery.

Decreasing Length of Hospital Stay and Postoperative Complications After Primary Total Hip Arthroplasty: A Decade Analysis From 2006 to 2016.

BACKGROUND: In an attempt to decrease costs without increasing complication burden, the development of rapid recovery protocols has led to an increased push for decreased length of hospital stay (LOS) following total hip arthroplasty (THA). The purpose of this study was to analyze trends in LOS and complications following THA over a 10-year period. METHODS: Using the National Surgical Quality Improvement Program registry from 2006 to 2016, we identified all patients who underwent primary THA. Patients were placed into 3 cohorts based on the year of surgery (2006-2009 [N = 3873], 2010-2013 [N = 45,992], 2014-2016 [N = 86,099]). Differences in LOS, operative time, readmission rates, and 30-day postoperative medical complications were compared using bivariate and multivariate analyses. RESULTS: Multivariate regression analysis identified a significant decrease in LOS in days for the 2010-2013 cohort (3.2 ± 4.8, P < .001) and 2014-2016 cohort (2.7 ± 2.5, P < .001) compared to the 2006-2009 cohort (3.8 ± 2.5). Despite decreasing LOS, there were significantly lower complications in the later cohorts, with significantly lower rates of all complications (5.27% [2006-2009], 3.77% [2009-2013], 3.14% [2013-2016]), sepsis (0.70%, 0.31%, 0.16%), and urinary tract infection (1.94%, 1.23%, 0.83%) using both bivariate and multivariate analyses (P < .001). In addition, there was no significant difference in unplanned 30-day readmissions (3.66% [2010-2013] vs 3.5% [2014-2016], P = .142). CONCLUSION: Over the last decade, there has been a decrease in LOS and an improved short-term complication profile for THA. With continually increasing rates of utilization of THA along broader patient demographics, these changes are important to help mitigate the costs of higher volume.

Step-wise medial collateral ligament needle puncturing in extension leads to a safe and predictable reduction in medial compartment pressure during TKA.

PURPOSE: Medial soft tissue release in a varus deformity knee during total knee arthroplasty is essential for accurate balancing of the reconstruction. This study attempts to quantify the effect of sequential needle puncturing of the medial collateral ligament (MCL) using a pressure sensor insert (Verasense by OrthoSensor) and gap measurement under tension. METHODS: Cruciate-retaining arthroplasties were placed in 14 cadaveric knees. The MCL was elongated by step-wise perforation, in five sets of five perforations, with the use of an 18-gauge needle, followed by valgus stress. Following the fifth set of needle perforations, blade perforation was performed on the remaining tense fibers of the MCL. Following each step-wise perforation, corresponding medial compartment pressures and gap measurements under tension were recorded. RESULTS: Sensor measurements correlated closely with step-wise tissue release (R = 0.73, p < 0.0001), and a significant decrease in pressure was found in early needle puncturing (mean 49 N after 5, 83 N after 15, p values < 0.05), although changes diminished at later stages of needle perforation (90 N after 20). Gap measurement demonstrated small gradual changes with early puncturing, but showed significant opening in the later stages of release. There was minimal variation in pressure or gap measurements in flexion versus extension. This finding suggests that MCL needle puncture will not lead to unequal gaps between flexion and extension. There were no cases of MCL over-release after 15 punctures, one case after 20 punctures, and three after blade perforation. CONCLUSION: Needle puncturing of the MCL in extension for up to 15 punctures can be a safe and predictable way to achieve medial opening when balancing a varus knee during TKA as demonstrated in this cadaveric model. Blade perforation should be used with caution to avoid over-release. The needle puncture method can be used by surgeons to achieve reliable reductions in medial compartment pressures, to help achieve a balanced TKA, with minimal risk of over-release.

Performance of implant sonication culture for the diagnosis of periprosthetic shoulder infection.

BACKGROUND: Diagnosing infection after shoulder arthroplasty can be a challenge because of the high prevalence of low-virulence organisms, such as Propionibacterium acnes. The purpose of this study was to evaluate the utility of implant sonication fluid cultures in the diagnosis of periprosthetic joint infection compared with standard culture techniques in patients undergoing revision shoulder arthroplasty. METHODS: Routine perioperative testing was performed in 53 patients who underwent revision shoulder arthroplasty. In addition to routine tissue and fluid culture, the retrieved shoulder implants underwent sonication with culture of the sonicate fluid. Diagnostic performance of implant sonication culture was determined on the basis of previously defined infection criteria and compared with standard intraoperative cultures. RESULTS: Of the 53 revision cases that underwent implant sonication fluid culture, 25 (47%) were classified as infected. Intraoperative culture (tissue and fluid) sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 96%, 75%, 77%, 95%, and 85%, respectively. Using a cutoff of >20 colony-forming units per milliliter to exclude contaminants, the sensitivity, specificity, PPV, NPV, and accuracy of implant sonicate culture were 56% (P < .001, compared with standard intraoperative cultures), 93% (P = .07), 88% (P = .4), 70% (P = .02), and 75% (P = .22), respectively. Without use of a sonication fluid culture cutoff value, the sensitivity, specificity, PPV, NPV, and accuracy of implant sonicate culture were 96% (P = 1.0, compared with standard intraoperative cultures), 64% (P = .38), 71% (P = .53), 95% (P = .9), and 79% (P = .45). CONCLUSIONS: Implant sonication fluid culture in revision shoulder arthroplasty showed no significant benefits over standard intraoperative cultures in diagnostic utility for periprosthetic joint infection.

Influence of Assembly Force and Distraction on the Femoral Head-Taper Junction.

BACKGROUND: This study investigates if the placement of femoral heads (trials and actual implants) using varying impaction forces causes physical compromise to the trunnion. METHODS: Trunnion and head taper wear patterns were evaluated after impaction and removal of new femoral stem trunnions and ceramic heads at various impaction loads (2 kN, 4 kN, or 6 kN, n = 6/group). In addition, trunnion wear patterns were measured after plastic trials were hand-placed on new trunnions and underwent range of motion testing in a Hip Simulator (n = 5). RESULTS: There was no significant difference in trunnion or head surface deviation, taper angle, or surface roughness in any groups preimpaction and postimpaction and removal. There was no significant surface trunnion damage from assembly and range of motion testing of the plastic femoral head trial. CONCLUSIONS: The use of femoral head trials and the concurrent impaction and removal of a new femoral head were not associated with significant trunnion surface damage for the impaction loads observed in this study.

Neer Award 2015: Analysis of cytokine profiles in the diagnosis of periprosthetic joint infections of the shoulder.

BACKGROUND: Periprosthetic joint infection (PJI) after shoulder arthroplasty can present a diagnostic and therapeutic challenge. This study evaluated the diagnostic utility of broader synovial fluid cytokine analysis for identifying PJI in patients undergoing revision shoulder arthroplasty. METHODS: Synovial fluid levels of 9 cytokines (interleukin [IL] 6, granulocyte-macrophage colony-stimulating factor, IL-1ß, IL-12, IL-2, IL-8, interferon-γ, IL-10, and tumor necrosis factor-α) were measured in 75 cases of revision shoulder arthroplasty with a multiplex immunoassay. Cases were classified into infection categories and groups based on objective perioperative findings. Differences in cytokine levels among infection groups were evaluated. Receiver operating characteristic curves were used to assess the diagnostic utility of the individual synovial fluid cytokines and combinations of cytokines in determining infection status. RESULTS: Synovial IL-6, granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1ß, IL-2, IL-8, and IL-10 were significantly elevated in cases of revision shoulder arthroplasty classified as infected. Individually, IL-6, IL-1ß, IL-8, and IL-10 showed the best combination of sensitivity and specificity for predicting infection, and a combined cytokine model consisting of IL-6, tumor necrosis factor-α, and IL-2 showed better diagnostic test characteristics than any cytokine alone, with sensitivity of 0.80, specificity of 0.93,, positive and negative predictive values of 0.87 and 0.89, and positive and negative likelihood ratios of 12.0 and 0.21. CONCLUSIONS: Individual and combined synovial fluid cytokine analysis were both more effective than routine perioperative testing, such as serum erythrocyte sedimentation rate and C-reactive protein, in the diagnosis of PJI of the shoulder. Once validated, combined synovial fluid cytokine analysis could be used as a predictive tool to determine the probability of PJI in patients undergoing revision shoulder arthroplasty and better guide treatment.