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The COVID-19 pandemic has led to unprecedented times worldwide. From lockdowns to masks now being part of our everyday routine, to the halting of elective surgeries, the virus has touched everyone and every part of our personal and professional lives. Perhaps, now more than ever, our ability to adapt, change and persevere is critical to our survival. This year's closed meeting of The Knee Society demonstrated exactly those characteristics. When it became evident that an in-person meeting would not be feasible, The Knee Society leadership, under the direction of President John Callaghan, MD and Program Chair Craig Della Valle, MD created a unique and engaging meeting held on September 10–12, 2020. Special recognition should be given to Olga Foley and Cynthia Garcia at The Knee Society for their flexibility and creativeness in putting together a world-class flawless virtual program.
Each year, the top research papers from The Knee Society meeting will be published and made available to the wider orthopaedic community in
The meeting is one of the highlights of the annual academic calendar for knee surgeons. With nearly every member in attendance virtually throughout the 3 days, the top research papers from the membership were presented and discussed in a virtual format that allowed for lively interaction and discussion. There are 75 abstracts presented. More selective proceedings with full papers will be available after a robust peer review process in 2021, both online and in
The meeting commenced with the first group of scientific papers focused on Periprosthetic Joint Infection. Dr Berry and colleagues from the Mayo Clinic further help to clarify the issue of serology and aspirate results to diagnose TKA PJI in the acute postoperative setting. 177 TKA's had an aspiration within 12 weeks and 22 were proven to have PJI. Their results demonstrated that acute PJI after TKA should be suspected within 6 weeks if CRP is ≥81 mg/L, synovial WBCs are ≥8500 cells/μL, and/or synovial neutrophils≥86%. Between 6– 12 weeks, concerning thresholds include a CRP ≥ 32 mg/L, synovial WBC ≥7450, and synovial neutrophils ≥ 84%. While historically the results of a DAIR procedure for PJI have been variable, Tom Fehring's study showed promise with the local delivery of vancomycin through the Intraosseous route improved early results. New member Simon Young contrasted the efficacy of the DAIR procedure when comparing early infections to late acute hematogenous PJI. DAIR failed in 63% of late hematogenous PJIs (implant age>1 year) compared to 36% of early (<1year) PJIs. Dr Masri demonstrated in a small group of patients that those with well-functioning articulating spacers can retain their spacers for over 12 months with no difference in infection from those that had a formal two stage exchange. The mental toll of PJI was demonstrated in a longitudinal study by Doug Dennis, where patient being treated with 2 stage exchange had 4x higher rates of depression compared to patient undergoing aseptic revision.
The second session focused on both postoperative issues with regards to anticoagulation and manipulation. Steven Haas demonstrated high complication rates with utilization of anticoagulation for treatment of postoperative pulmonary embolism with modern therapeutic anticoagulation (warfarin, enoxaparin, Xa inhibitors) with the Xa inhibitors demonstrating lower complication rates. Two papers focused on the topic of manipulation. Mark Pagnano presented data on timing of manipulation under anesthesia up to even past 12 months. While gains were modest, a subset of patients did achieve substantial gains in ROM > 20degrees even after 3 months post op. Dr Westrich's study demonstrated no difference in MUA outcomes with either IV sedation or neuraxial anesthesia although the length of stay was shorter in the IV sedation group. Several studies in Session II focused on kinematics and femoral component position. Dr Li's in vivo kinematic study during weightbearing flexion and gait demonstrated that several knees rotated with a lateral pivot motion and not all knees can be described with a single motion character. Dr Mayman and his group utilized a computational knee model to demonstrate that additional distal femoral resection results in increasing levels of mid -flexion instability and cautioned against the use of additional bony resection as the first line for flexion contractures. Using computer navigation, Dr Huddleston's study nicely outlined the variability in femoral component rotation to achieve a rectangular flexion gap utilizing a gap balanced method.
The third session opened the meeting on Friday morning. The focus was on unicompartmental knee arthroplasty and the increasing utilization of robotic assisted total knee arthroplasty. David Murray showed using registry data that for patient with higher comorbidities (ASA >3), UKA was safer and more cost effective than TKA while Dr Della Valle's group demonstrated overall lower average healthcare costs in UKA patients compared to TKA in the first 10 years after surgery. Dr Geller assessed UKA survivorship among 3 international registries. While survivorship varied by nation and designs, certain designs consistently had better overall performance. Dr Nunley and his group showed robotic navigation UKA significantly reduced outliers in alignment and overhang compared to manual UKA. Dr Catani's data demonstrated that full thickness cartilage loss should still be considered a requirement for UKA success even with robotic assistance. Despite a high dislocation rate of 4%, Mr Dodd demonstrated high survivorship for lateral UKA despite historical contraindications. The growing evidence for robotics TKA was demonstrated in two studies. Professor Haddad showed less soft tissue injury, reduced bone trauma and improved accuracy or rTKA compared to manual TKA while Dr Gustke single surgeon study showed his rTKA had improved forgotten joint scores and less ligament releasing required for balancing. Despite these finding, Dr Lee's study demonstrated that a robotic TKA could not guarantee excellent pain relief and other factors such a patient expectations and psychological factors play a role.
Our fourth session was devoted to machine learning and smart tools and modeling. Dr Meneghini used machine learning algorithms to identify optimal alignment outcomes that correlated with patient outcomes. Several parameters such as native tibial slope, femoral sagittal position and coronal limb alignment correlated with outcomes. Along the same lines, Bozic and coauthors demonstrated that using AI algorithms incorporated with PROM's improved levels of shared decision making and patient satisfaction. Dr Lombardi demonstrated that a mobile patient engagement platform that provided smart phone-based exercise and education was comparable to traditional methods. Dr Mahfouz demonstrated the accuracy of using ultrasound to produce 3D models of the bone compared to conventional CT based strategies and Dr Mahoney showed the valued of a preop 3D model in reproducing more normal knee kinematics. The last two talks of the session focused on some of the positives of the COVID-19 pandemic, namely the embracing of telemedicine by patients and surgeons as demonstrated by Dr Slover and the increasing and far reaching educational opportunities made available to residents and fellows during the pandemic.
Session five focused on risk stratification and optimization prior to TKA. Dr O'Connor demonstrated that that the implementation of an optimization program preoperatively reduced length of stay and ED visits, and Charles Nelson's study showed that risk stratification tool can lower complication rates in obese patients undergoing TKA comparable to those that are nonobese. Dr Markel's study demonstrated that those who have preoperative depression and anxiety are at higher risk of complications and readmissions after surgery and these issues should be addressed preoperatively. Interestingly, a study by Dr Callaghan demonstrated that care improvement pathways have not lowered the gap in complications for morbidly obese patients undergoing TKA, Dr Barsoum argued that the overall complication rates were low and this patient cohort had significant gains in PROMS after TKA that would not be experienced if arbitrary cutoff for limited surgery were established.
The final session on Friday, Session six, had several well done and interesting studies. There continues to be mounting evidence that liposomal bupivacaine has little effect on managing post-operative pain to warrant its increased use. Bill Macaulay and colleagues showed no change in pain scores, opioid consumption and functional scores when liposomal bupivacaine was discontinued at a large academic medical center. Dr Bugbee importantly demonstrated that a supervised ambulation program reduced falls in the early postoperative period. Several paper on healthcare economics were presented. Rich Iorio showed that stratifying complexity of total joint cases between hospitals with a system can be efficient and cost savings while Dr Jiranek demonstrated in his study that complex TKAs can be identified preoperatively and are associated with prolonged operative time and cost of care and consideration should be given in future reimbursement models to a complexity modifier. Dr Springer, in their evaluation of Medicare bundled payment models, demonstrated that providers and hospitals in historical bundled models that became efficient were penalized in the new model, forcing many groups to drop out and return to a fee for service model. Ron Delanois important work showed that social determinants can have a major negative impact on outcomes following TKA.
Our final day on Saturday opened with Session seven, and several interesting paper on metal ions/debris in TKA. Dr Whitesides simulator study showed the absence of scratches and material loss in a ceramic TKA compared with Co-Cr TKA and suggested an advantage to this material in patients with metal sensitivity. Conversely, in a histological study of failed TKA, perivascular lymphocytic infiltration was not associated with worse clinical outcomes or differences in revision in a series of 617 aseptic revisions, 19% of which had PVLI found on histology. The Mayo group and Dr Trousdale however, noted that serum metal ion levels can be helpful in identifying implant failure in a group of revision TKAs, especially those with metallic junctions.
Dr Dalury demonstrated nicely that use of maximally conforming inserts did not have a negative effect on implant loosening in a series of 76 revision TKA's at an average follow up of 7 years, while Kevin Garvin and his group showed no difference in end of stem pain between cemented and cementless stems in revision TKA. The final two studies in the session by Bolognesi and Peters respectively showed that metaphyseal cones continue to demonstrate excelled survivorship in rTKA setting despite extensive bone loss.
Session eight was highlighted by a large series of revision reported by new member Dr Schwarzkopf, who showed that revision TKA done by high volume surgeons demonstrated better outcomes and lower revision rates compared to surgeon who did less than 18 rTKA's per year. Dr Maniar importantly showed that preoperatively, patients with high activity level and low pain and indicated by a high preop forgotten joint score did poorly following TKA while David Ayers nicely demonstrated that KOOS scores that assess specific postoperative outcomes can predict patient dissatisfaction after TKA. The final paper in this session by Max Courtney showed that the majority of surgical cancellations are due to medical issues, yet a minority of these undergo any intervention specifically for that condition, but they resulted in a delay of 5 months.
The first two studies of Session nine focused on polyethylene thickness. Dr Backstein demonstrated no difference in KSS scores, change in ROM and aseptic revision rates based on polyethylene thickness in a series of 195 TKA's. An interesting lab study by Dr Tim Wright showed a surprising consistency in liner thickness choice among varying levels of surgeon experience that did not correlate with applied forces or gap stability estimates. Two studies looked specifically at the issue of tibial loosening and implant design. Nam and colleagues were not able to demonstrate concerning findings for increasing tibial loosening in a tibial baseplate with a shortened tibial keel at short term follow up, while Lachiewicz demonstrated a 19% revision or revision pending rate in 223 cemented fixed bearing ATTUNE TKA at a mean of 30 months.
Our final session of the meeting, began with encouraging news, that despite only currently capturing about 40% of TJA's done in the US, the American Joint Replacement Registry data is representative of data in other representative US databases. An interesting study presented by Robert Barrack looked at bone remodeling in the proximal tibia after cemented and cementless TKA of two different designs. No significant difference was noted among the groups with the exception of the cemented thicker cobalt chrome tray which demonstrated significantly more bone mineral density loss. Along the same lines, a study out of Dr Bostrom's lab demonstrated treatment of a murine tibial model with iPTH prevents fibrous tissue formation and enhances bone formation in cementless implants. New Member Jamie Howard showed no difference in implant migration and kinematics of a single radius cementless design using either a measured resection or gap balancing technique and Dr Cushner show no difference in blood loss with cemented or cementless TKA with the use of TKA. The final two studies looked at staging and bilateral TKA's. Peter Sharkey showed that simultaneous TKA's were associated with higher complication compared to staged TKA and that staged TKA with less than a 90-day interval was not associated with higher risk. However, Mark Figgie showed that patients undergoing simultaneous TKA compared to staged TKA, missed 17 fewer days of work.
In spite of the virtual nature of the meeting, there were some outstanding scientific interactions and the material presented will continue to generate debate and to guide the direction of knee arthroplasty as we move forwards.
Introduction
Diagnosing acute postoperative periprosthetic joint infections (PJIs) after primary total knee arthroplasties (TKAs) remains difficult. Published diagnostic thresholds for ESR, CRP, and synovial fluid analysis have not been replicated. We aimed to validate the optimal cutoffs for detecting acute postoperative PJIs in a large series of primary TKAs.
Methods
We retrospectively identified 27,066 primary TKAs performed between 2000–2019. Within 12 weeks, 171 knees (170 patients) had a synovial fluid aspiration. Patients were divided into two groups: evaluation <6 weeks or 6–12 weeks. The 2011 MSIS criteria for PJI diagnosed infection in 22 knees. Mann-Whitney U tests compared medians; ROC analyses determined optimal thresholds. Mean follow-up was 5 years.
Introduction
Debridement, Antibiotics and Implant Retention (DAIR) remains the norm for the treatment of acute periprosthetic joint infection (PJI) despite less than optimal success rates. Intraosseous (IO) administration of vancomycin has been shown to have significantly increased local bone and tissue concentrations compared to systemic antibiotics, with lower systemic antibiotic levels compared to intravenous. The purpose of this study was to evaluate if the addition of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.
Methods
A retrospective review of 35 PJI TKA patients who underwent DAIR combined with IO vancomycin (500mg) was performed with minimum 12-month follow-up. 26 patients were treated for acute perioperative or acute hematogenous infections following primary TKA. Nine were treated for chronic infections with components that were considered unresectable (ie) constructs with ingrown cones, sleeves, or long cemented stems in elderly comorbid patients. Primary outcome was defined by no reoperations for infection nor clinical signs or symptoms of PJI.
Introduction
Treatment of prosthetic joint infection (PJI) following total knee arthroplasty (TKA) may guided by PJI classification, taking into account infection duration and potential for biofilm formation. Debridement, antibiotics and implant retention (DAIR) is recommended for ‘post-operative’ and ‘acute’ haematogenous PJI. However, the time cut-off for ‘post-operative’ PJI varies across classification systems. Furthermore, poor DAIR success rates have been reported in acute haematogenous PJIs. This study aimed to determine the success of DAIR in a large cohort of PJIs, and assess the utility of current classification systems for predicting DAIR outcomes.
Method
In this multicentre retrospective, cohort study, we identified 230 patients undergoing DAIR for first episode PJI following primary TKA. Patient demographics, disease and surgical factors were identified, and PJI subtype, post-operative antibiotic regime and treatment outcomes were recorded. Statistical analysis was performed to identify factors associated with failed DAIR, and success rates were analysed by multiple classification systems using receiver operating characteristic (ROC) curves.
Introduction
Our objective is to describe early and midterm results with the use of a new knee prosthesis as an articulating spacer in planned two-stage management for infected total knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a completed 2-stage revision.
Methods
Forty-seven patients (48 knees) from January 2012 and November 2017 underwent a 2-stage exchange with an articulating spacer with new implants was used for a chronic knee periprosthetic joint infection with a mean follow-up of 3.7 years (2–6.5 years).
The most frequently identified infecting organism was MSSA (31%), MRSA (21%) or MRSE (20%). At the first stage, a new PS femoral component and a new all-polyethylene posterior stabilized (PS) tibial component or a standard PS tibial liner were cemented with antibiotic-cement, typically 3.6 gm tobramycin and vancomycin 1.5 gm. IV antibiotics for six weeks were administered. The planned reimplantation was at 3 months, but ninetteen spacers (14 all poly tibias and 5 tibial liner) were retained for over 12 months.
Postoperative assessment included knee range of motion (ROM), quality of life (QOL) scores (SF-12, WOMAC, KOOS, Oxford, and UCLA scores), and a satisfaction scale from 0–100%.
Introduction
Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty. Patients undergoing revision for PJI may experience considerable psychological distress and symptoms of depression, both of which are linked to poor post-operative outcomes. We therefore aim to identify the prevalence of depressive symptoms in patients prior to treatment for PJI.
Methods
All patients between September 2008 – October 2018 undergoing single or 2-stage revision for PJI with minimum 1-year follow-up were retrospectively reviewed at a single institution. The 2-stage (n=37) and single stage (n=39) patients that met inclusion criteria were matched based off age (+/−5), gender and BMI (+/−5) to patients undergoing aseptic revisions. Based on prior literature, patients were considered to have depressive symptoms if their VR-12 mental component score (MCS) was below 42. Using Student's t-tests, outcomes evaluated included pre-operative and 1-year post-operative VR-12 MCS and physical component scores (PCS).
Introduction
Surgical management of PJI remains challenging with patients failing treatment despite the best efforts. An important question is whether these later failures reflect reinfection or the persistence of infection. Proponents of reinfection believe hosts are vulnerable to developing infection and new organisms emerge. The alternative hypothesis is that later failure is a result of an organism that was present in the joint but was not picked up by initial culture or was not a pathogen initially but became so under antibiotic pressure. This multicenter study explores the above dilemma. Utilizing next-generation sequencing (NGS), we hypothesize that failures after two stage exchange arthroplasty can be caused by an organism that was present at the time of initial surgery but not isolated by culture.
Methods
This prospective study involving 15 institutions collected samples from 635 revision total hip (n=310) and knee (n=325) arthroplasties. Synovial fluid, tissue and swabs were obtained intraoperatively for NGS analysis. Patients were classified per 2018 Consensus definition of PJI. Treatment failure was defined as reoperation for infection that yielded positive cultures, during minimum 1-year follow-up. Concordance of the infecting pathogen cultured at failure with NGS analysis at initial revision was determined.
Introduction
Management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a challenging task. Antibiotic management remains elusive due to differences in epidemiology and resistance between countries and reports. Increasing resistance of bacteria is a concern. The aim of this study was to investigate the development of antibiotic resistance of main causative bacteria in a single center.
Methods
A retrospective review of all revision TKA between 2006 and 2018 in a tertiary referral center was performed. Included were cases meeting the consensus criteria for PJI with at least two positive cultures. Three chronological groups were created using a two-step cluster analysis.
Background
There are limited data on the complication rates and risk of periprosthetic joint infection (PJI) in patients who have an acute wound dehiscence after total knee arthroplasty (TKA).
Methods
From 2002 to 2018, 16,134 primary TKAs were performed at a single institution. Twenty-six patients (0.1%) had a traumatic wound dehiscence within the first 30 days. Mean age was 68, 38% were female, and mean BMI was 33 kg/m2. Median time to dehiscence was 13 days. The dehiscence resulted from a fall in 22 cases, including 4 in-hospital falls (3 with femoral nerve blocks), and sudden flexion after staple removal in 4 cases. The arthrotomy was disrupted in 58%, including a complete extensor mechanism disruption in 4 knees. A surgical debridement was performed within 48 hours in 19 of 26 knees. Two-thirds were discharged on antibiotic therapy.
Introduction
Septic arthritis of the native knee often results in irreversible joint damage leading to the need for a total knee arthroplasty (TKA). This study examines the mid-term risk of periprosthetic joint infection (PJI), aseptic revision, any revision, and any reoperation in primary TKAs after septic arthritis of the native knee compared to a control cohort of primary TKAs performed for osteoarthritis (OA).
Methods
We retrospectively identified 215 primary TKAs performed between 1971 and 2016 at a single institution following septic arthritis of the native knee. Eighty-two percent (177 cases) were treated in a single setting, whereas a two-stage exchange arthroplasty protocol was utilized in 18% (39 cases) for ongoing or suspected active native knee septic arthritis. Each case was matched 1:1 based on age, sex, body mass index (BMI), and surgical year to a primary TKA for OA. Mean age and BMI were 63 years and 30 kg/m2, respectively. Mean follow-up was 9 years.
Introduction
Pulmonary embolism (PE) complicates up to 1% of total joint arthroplasties (TJA). Many PE treatment guidelines call for immediate initiation of therapeutic anticoagulation. Options include Xa inhibitors, Enoxaparin, and Warfarin. Deciding between these is a balance of the efficacy and the risks. Little data exists regarding the risks of each of these treatment options for treating PE in arthroplasty patients.
Methods
We examined the records of 29,270 patients who underwent a primary total joint arthroplasty (TJA), defined as a unilateral total knee arthroplasty (TKA) (18,987) or total hip arthroplasty (THA) (10,283), between 2/2016 and 12/2018 at our institution and identified 338 (242 TKA, 96 THA) patients who developed an in-hospital PE treated with therapeutic anticoagulation. The patients were treated with therapeutic doses of Xa inhibitors, enoxaparin or warfarin. The type and frequency of complications were determined and classified as major or minor. Major complication included: bleeding requiring surgery, GI bleed requiring treatment, >2 unit transfusion and mortality. Minor complications included wound drainage, bleeding not requiring surgery, and thrombocytopenia.
Introduction
Arthrofibrosis remains a persistent complication following total knee arthroplasty (TKA). Although manipulation under anesthesia (MUA) is an effective early treatment, the risks and value of this procedure beyond 3 months after TKA remain controversial. The purpose of this study was to examine the safety and efficacy of late MUAs for arthrofibrosis.
Methods
From our institutional total joint registry, 82 TKAs (77 patients) who underwent MUA >3 months after primary (83%) or revision (17%) TKA were identified. Mean time to MUA was 7 months: 66% performed between 4–6 months, 18% between 7–12 months, 16% beyond 12 months. MUAs were coupled with arthroscopic assistance in 26% (12% limited lysis of adhesions, 13% formal arthroscopic debridement). Mean age was 61 years, 59% females, and mean BMI was 33kg/m2. Mean follow-up was 5 years.
Introduction
Manipulation under anesthesia (MUA) remains the gold standard to address restricted range of motion (ROM) within 3–6 months after primary total knee arthroplasty (TKA). However, there is little data on the outcomes of MUA with different types of anesthesia. We sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anesthesia.
Methods
We identified 548 MUAs after primary TKA (136 IV sedation, 413 neuraxial anesthesia) at a single institution from 2016–2019. Mean age was 62 years and 349 patients (64%) were female. Mean body mass index was 32 kg/m2. The mean time from primary TKA to MUA was 10 weeks. Mean pre-MUA ROM was similar between each group; mean pre-MUA extension was 4.2° (p=0.35) and mean pre-MUA flexion was 77° (p=0.56). Patient demographics were statistically similar between both groups. We compared immediate complications, including fracture, extensor mechanism disruptions, and wound complications, Visual analogue pain scores (VAS), length of stay (LOS), and immediate and 3 month follow-up ROM between these groups.
Introduction
Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture. However, the effect of joint line proximalization on TKA kinematics is unclear. Thus, our goal was to quantify the effect of additional distal femoral resection on knee extension and mid-flexion laxity.
Methods
Six computational knee models with TKA-specific capsular and collateral ligament properties were implanted with a contemporary posterior-stabilized TKA. A 10° flexion contracture was modeled to simulate a capsular contracture. Distal femoral resections of +2 mm and +4 mm were simulated for each model. The knees were then extended under standardized torque to quantify additional knee extension achieved. Subsequently, varus and valgus torques of ±10 Nm were applied as the knee was flexed from 0° to 90° at the baseline, +2 mm, and +4 mm distal resections. Coronal laxity, defined as the sum of varus and valgus angulation with respective torques, was measured at mid-flexion.
Introduction
Medial pivoting motion of the knee has been widely assumed in total knee arthroplasty (TKA) research, but was not consistently observed in recent studies of
Methods
Introduction
Vancomycin is a commonly used antibiotic for prophylaxis in total joint replacement surgery. Several studies have reported superior local tissue concentration of vancomycin using intraosseous (IO) infusion compared with standard intravenous (IV) administration in total knee arthroplasty (TKA). We reviewed patients undergoing primary TKA who received IO vancomycin to a group receiving IV vancomycin.
Methods
A retrospective review of 1038 patient who underwent primary TKA at our institution was performed from May 1, 2016 to May 1, 2019. This was a consecutive series of patients before and after we adopted this technique. IO vancomycin administration technique has been previously reported from our institution (500mg vancomycin in 200mL solution). Comparisons included preoperative and postoperative creatinine values, adverse reaction to vancomycin, tourniquet time, re-operation rates, periprosthetic joint infection rate at 1 year.
Introduction
Instability is a common reason for revision after total knee arthroplasty. A balanced flexion gap is likely to enhance stability throughout the arc of motion. This is achieved differently by the gap balancing and measured resection techniques. Given similar clinical results with the two techniques, one would expect similar rotation of the femoral component in the axial plane. We assessed posterior-stabilized femoral component axial rotation placed with computer navigation and a modified gap balancing technique. We hypothesized that there would be little variation in rotation.
Methods
90 surgeons from 8 countries used a modified gap-balancing technique and the same posterior-stabilized implant for this retrospective study. Axial rotation of the femoral component was collected from a navigation system and reported relative to the posterior condylar line. Patients were stratified by their preoperative coronal mechanical alignment (≥ 3° varus, < 3° varus to < 3° valgus, and ≥ 3° valgus).
Introduction
Clinical examination for stability in knee replacement involves the anterior drawer test. This test has been used to help in the diagnosis of flexion instability when used at 90 degrees and midflexion instability at 30 degrees. We sought to determine the inter-rater reliability of this test when compared to motion capture data.
Methods
10 subjects with previous knee repalcement were examined by four orthopedics knee repalcement surgeons in one setting. Each surgeon evaluated each subject in random order and was blinded from the results of the other surgeons. Each surgeon performed an anterior drawer test at 30 and 90 degrees and graded the instability as 0–5mm, 5–10mm or >10 mm. Anterior posterior translation was measured using motion capture.
Background
There are advantages and disadvantages of Unicompartmental (UKR) and Total Knee Replacement, with UKR having better functional outcomes with fewer complications but a higher revision rate. The relative merits depend on patient characteristics. The aim was to compare UKR and TKR risk-benefits and cost-effectiveness in patients with severe systemic morbidity.
Methods
Data from the National Joint Registry for England, Wales and Northern Ireland was linked to hospital inpatient and patient-reported outcomes data. Patients with American Society of Anesthesiologists (ASA) grade ≥3 undergoing UKR or TKR were identified. Propensity score stratification was used to compare 90-day complications and 5-year revision and mortality of 2,256 UKR and 57,682 TKR, and in a subset of 145 UKR and 23,344 TKR Oxford Knee Scores (OKS). A health-economic analysis was based on EQ-5D and NHS hospital costs.
Introduction
Both mobile bearing and fixed bearing unicompartmental knee arthroplasty (UKA) have demonstrated clinical success. However, much debate persists about the superiority of a single design. Currently most clinical data is based on high volume centers data, however to reduce bias, we undertook a through review of retrospective national joint registries. In this study, we aim to investigate UKA implant utilization and survivorship between 2000 and 2018.
Methods
Ten annual joint registry reports of various nations were reviewed. Due to the variable statistical methods of reporting implant use and survivorship we focused on three registries: Australia (AOANJRR), New Zealand (NZJR), United Kingdom (NJR) for uniformity. We evaluated UKA usage, survivorship, utilization and revision rates for each implant. Implant survivorship was reported in the registries and was compared within nations due to variation in statistical reporting.
Introduction
The proportion of arthroplasties performed in the ambulatory setting has increased substantially. However, concerns remain regarding whether same-day discharge may increase the risk of complications. The purpose of this study was to compare 90-day outcomes between inpatients and patients having surgery at an ambulatory surgery center (ASC).
Methods
Among a single-surgeon cohort of 721 patients who underwent arthroplasty at a free-standing ASC, 611 (84.7%) were matched one-to-one to inpatients based on age, gender, American Society of Anesthesiologists (ASA) score, and Body Mass Index (110 patients could not be adequately matched). The cohort included 208 total hip arthroplasties (34.0%), 196 total knee arthroplasties (32.1%), 178 unicompartmental knee arthroplasties (29.1%), 25 hip resurfacings (4.1%), two revision hip arthroplasties (0.3%) and two revision knee arthroplasties (0.3%). Post-operative outcomes including readmissions, reoperations, unplanned clinic visits, emergency department visits, and complications were compared. Complications were classified as either major (i.e. death, periprosthetic joint infection, pulmonary embolism) or as minor (i.e. delayed wound healing, rashes, urinary retention).
Background
Lateral Unicompartmental Knee Arthroplasty (UKA) is a recognised treatment option in the management of lateral Osteoarthritis (OA) of the knee. Whilst there is extensive evidence on the indications and contraindcations in Medial UKA there is limited evidence on this topic in Lateral UKA. The aim of this study was to assess our experience of mobile lateral UKR and to look specifically at the effect of Contraindications on the outcome.
Method
A total of 325 consecutive domed lateral UKAs undertaken for the recommended indications were included, and their functional and survival outcomes were assessed. The effects of age, weight, activity, and presence of full- thickness erosions of cartilage in the patellofemoral joint on outcome were evaluated.
Background
Unicompartmental knee arthroplasty (UKA) patients with knee partial thickness cartilage loss have inferior functional performance compared to those with full thickness loss. Therefore, the aim of the present study was to investigate on the association between postoperative patients' joint awareness and satisfaction and preoperative radiographic osteoarthritis (OA) Ahlbäck grade in subjects undergoing robotic arm-assisted UKA.
Methods
This retrospective observational study includes 675 patients (681 knees) undergoing robotic arm-assisted UKA at two centres between January 2014 and May 2019. Pre-operatively, knee radiographs were performed, and Ahlbäck OA grade was measured by two independent observers. Post-operatively, patients were administered the Forgotten-Joint-Score-12 (FJS-12) and 5-Level-Likert-Scale to assess joint awareness and satisfaction. Postoperative complications and revisions were recorded. Correlations were described between FJS-12, satisfaction and OA grade by means of an adjusted multivariate statistical analysis.
Introduction
The purpose of this study was to compare the radiographic outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA).
Materials & Methods
Postoperative radiographic outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic center were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiographically measured to identify outliers. Clinical results at 4–6 weeks postoperative were compared to a control cohort of total knee arthroplasty (TKA) patients from our institution.
Introduction
The objectives of this study were to compare the systemic inflammatory reaction, localised thermal response and macroscopic soft tissue injury outcomes in conventional jig-based total knee arthroplasty (conventional TKA) versus robotic total knee arthroplasty (robotic TKA).
Methods
This prospective randomised controlled trial included 30 patients with symptomatic knee osteoarthritis undergoing conventional TKA versus robotic TKA. Predefined serum markers of inflammation and localised knee temperature were collected preoperatively and postoperatively at 6 hours, day 1, day 2, day 7, and day 28 following TKA. Blinded observers used the Macroscopic Soft Tissue Injury (MASTI) classification system to grade intraoperative periarticular soft tissue injury and bone trauma. Plain radiographs were used to assess the accuracy of achieving the planned limb alignment and implant positioning in both treatment groups.
Introduction
The purpose of this study was to determine if better outcomes occur with use of robotic-arm assistance by comparing consecutive series of non-robotic assisted (NR-TKA) and robotic-arm assisted (NR-TKA) total knee arthroplasties with the same implant.
Methods
80 NR-TKAs and then 101 RA-TKAs were performed consecutively. 70 knees in each group that had a minimum two-year follow-up were retrospectively reviewed. Range of motion, Knee Society (KS) scores, and forgotten joint scores (FJS) were compared using Mann-Whitney U tests.
Tourniquets, used for all cases, had their inflation time recorded. Component realignment to minimize soft tissue releases was used in both groups with the goal to stay within a mechanical alignment of 3° of varus to 2° of valgus. The use of soft tissue releases for balance were compared.
Introduction
Neither a surgeon's intraoperative impression or computer navigation parameters have been shown to be predictive of postoperative outcomes following TKA. The purpose of this study is to determine 1) whether a surgeon and a robot can predict the 1-year KOOS pain score (KPS) and 2) determine what factors correlate with poor KOOS scores in well aligned and balanced TKA.
Methods
The data of 131 consecutive patients enrolled in a prospective trial was reviewed. All TKAs were performed using a dynamic ligament tensioning robotic system with a tibial first resection technique and a cruciate sacrificing ultracongruent knee implant. Each TKA was graded based on the final recorded mediolateral ligament balance at 10° and 90°: A) <1mm with an implanted insert thickness equal to planned (n=74); B) <1mm (n=25); C) <2mm (n=26); D) >2mm (n=6) (Table-1). The 1-year KPS for each knee grade were compared and the likelihood of achieving an KPS > 90 was calculated. Finally, the factors associated with lower KPS despite achieving a high grade TKA (A/B) was performed. The Mann-Whitney U test and Chi-squared analysis was performed.
Introduction
Robot-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to quantify soft tissue laxity and adjust the plan prior to bone resection should reduce variability in polyethylene thickness. This study was performed to compare accuracy to plan for component positioning and polyethylene thickness in RA-TKA versus M-TKA.
Methods
199 consecutive primary TKAs (96 C-TKA and 103 RA-TKA) performed by a single surgeon were reviewed. Full-length standing and knee radiographs were obtained pre and post-operatively. For M-TKA, measured resection technique was used. Planned coronal plane femoral and tibial component alignment, and overall limb alignment were all 0° to the mechanical axis; tibial posterior slope was 2°; and polyethylene thickness was 9mm. For RA-TKA, individual component position was adjusted to assist balance the gaps but planned coronal plane alignment for the femoral and tibial components and overall limb alignment had to remain 0+/− 3°; planned tibial posterior slope was 1.5°. Planned values and polyethylene thickness for RA-TKA were obtained from the final intra-operative plan. Mean deviations from plan for each parameter were compared between groups (ΔFemur, ΔTibia, ΔPS, and polyethylene thickness) as were distal femoral recut and tourniquet time.
Background
Advanced technologies, like robotics, provide enhanced precision for implanting total knee arthroplasty (TKA) components; however, optimal component position and limb alignment remain unknown. This study purpose was to identify the ideal target sagittal component position and coronal limb alignment that produce optimal clinical outcomes.
Methods
A retrospective review of 1,091 consecutive TKAs was performed. All TKAs were PCL retaining or sacrificing with anterior lipped (49.4%) or conforming bearings (50.6%) performed with modern perioperative protocols. Posterior tibial slope, femoral flexion, and tibiofemoral limb alignment were measured with a standardized protocols. Patients were grouped by the ‘how often does your knee feel normal?’ outcome score at latest follow-up. Machine learning algorithms were used to identify optimal alignment zones which predicted improved outcomes scores.
Background
The purpose of this study is to evaluate the early perioperative outcomes after primary knee arthroplasty with the use of a smartphone-based exercise and educational platform compared to a standard of care control group.
Methods
A multicenter prospective randomized control trial was conducted evaluating the use of the mymobility smartphone-based care platform for primary total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA). Patients in the control group (224 patients) received the respective institution's standard of care typically with formal physical therapy. Those randomized to mymobility treatment group (192 patients) were provided an Apple Watch and mymobility smartphone application. The treatment group was not initially prescribed physical therapy, but could if their surgeon determined it necessary. Early outcomes assessed included 90-day knee range of motion, KOOS Jr scores, 30-day single leg stance (SLS) time, Time up and Go (TUG) time and need for manipulation under anesthesia (MUA). There was no significant difference in age, BMI or gender between groups.
Introduction
The application of artificial intelligence (A.I) using patient reported outcomes (PROs) to predict benefits, risks, benefits and likelihood of improvement following surgery presents a new frontier in shared decision-making. The purpose of this study was to assess the impact of an A.I-enabled decision aid versus patient education alone on decision quality in patients with knee OA considering total knee replacement (TKR). Secondarily we assess impact on shared decision-making, patient satisfaction, functional outcomes, consultation time, TKR rates and treatment concordance.
Methods
We performed a randomized controlled trial involving 130 new adult patients with OA-related knee pain. Patients were randomized to receive the decision aid (intervention group, n=65) or educational material only (control group, n=65) along with usual care. Both cohorts completed patient surveys including PROs at baseline and between 6–12 weeks following initial evaluation or TKR. Statistical analysis included linear mixed effect models, Mann-Whitney U tests to assess for differences between groups and Fisher's exact test to evaluate variations in surgical rates and treatment concordance.
Introduction
The COVID-19 pandemic led to a swift adoption of telehealth in orthopedic surgery. The purpose of this study was to analyze patient and surgeon satisfaction with a rapid expansion of telehealth use during COVID-19 pandemic within the division of adult reconstructive surgery at a major urban academic hospital.
Methods
334 hip and knee arthroplasty patients who completed a telemedicine visit from March 30th, 2020 through April 30th, 2020 were sent a 14-question survey. Eight adult reconstructive surgeons who used telemedicine were sent a separate 14-question survey at the end of the study period. Factors influencing patient satisfaction were determined using univariate and multivariate ordinal logistic regression modeling.
Background
The COVID-19 pandemic caused an abrupt disruption in fellowship training, with most in-person teaching ceasing in mid-March 2020. An online lecture series was quickly initiated named the Fellows Online COVID-19 AAHKS Learning (FOCAL) initiative. This study will summarize the results of that initiative.
Methods
Beginning March 31, 2020, an online teaching program was initiated. Adult reconstruction fellows and senior residents with interest in adult reconstruction were invited to participate in the free, live, online education sessions. Faculty from well-respected training institutions from around the country volunteered their time to host the initiative, choosing topics to present, ranging from hip (13 lectures) and knee (9), to practice management/miscellaneous (12). All sessions were recorded and posted on the society website for viewing. Attendee registrations were tracked via the online platform and the maximum number of attendees per session was recorded. A survey was administered to attendees for feedback.
Introduction
The objective of this study is to assess the use of ultrasound (US) as a radiation free imaging modality to reconstruct three-dimensional knee anatomy.
Methods
An OEM US system is fitted with an electromagnetic (EM) tracker that is integrated into the US probe, allowing for 3D tracking of probe and femur and tibia. The raw US RF signals are acquired and using real time signal processing, bone boundaries are extracted. Bone boundaries are then combined with the EM sensor information in a 3D point cloud for both femur and tibia. Using a statistical shape model, the patient specific surface is reconstructed by optimizing bone geometry to match the point clouds. An accuracy analysis was then conducted for 11 cadavers by comparing the 3D US models to those created using CT scans.
Introduction
The role of the (PCL) in modulating knee kinematics has been well documented. We asked whether function of the (PCL) would be better preserved by incorporating a three-dimensional model for planning and placement.
Methods
We evaluated patients (n=59) enrolled into a, prospective, study of conventional instrumentation (25) vs. 3D modeling (34) for (CR) TKA from July 2016 to Feb 2018. Follow-up included clinical exams, PROMs, and serial radiographs up to 24 months after surgery. We measured kinematic patterns radiographically at two years postoperatively. Variables were compared using simple linear regression, one-way ANOVA, and Fisher's exact test. We hypothesized that: 1. well-preserved PCL would demonstrate a more normal kinematic pattern of increasing rollback with increasing knee flexion without paradoxical movement, and 2. this pattern would be associated with improved intra- and post-operative motion and function.
Background
The evaluation and management of outcomes risk has become an essential element of a modern total joint replacement program. Our multidisciplinary team designed an evidence-based tool to address modifiable risk factors for adverse outcomes after primary hip and knee arthroplasty surgery.
Methods
Our protocols were designed to identify, intervene, and mitigate risk through evidence-based patient optimization. Nurse navigators screened patients preoperatively, identified and treated risk factors, and followed patients for 90 days postoperatively. We compared patients participating in our optimization program (N=104) to both a historical cohort (N=193) and a contemporary cohort (N=166).
Introduction
Patients undergoing TJA have higher rates of anxiety and/or depression than the general population and higher costs of care. These preoperative diagnoses lead to higher levels of postoperative dissatisfaction and depression patients alone have higher readmission rates. There is significant crossover between anxiety and depressive disorders, and many patients are classed as combined. Our goal was to evaluate readmission rates of patients undergoing total hip or knee arthroplasty with diagnoses of anxiety, depression or both.
Methods
Our hospital's prospectively collected data from our statewide total joint database (MARCQI) was reviewed from 2013–2018. Rates of anxiety and/or depression were determined based preoperative anxiolytic or antidepressant medications using national drug codes. Independent sample t-tests compared continuous variables and Chi-square tests (or Fisher's exact tests) compared categorical variables. Potential risk factors were identified by multivariable logistic regression modeling.
Introduction
Previous research has indicated that preoperative modification of risk factors associated with obesity may reduce complications after TKA. However, the optimal method is still debated. This study aims to investigate whether a preoperative Risk Stratification Tool (RST) devised by our institution to optimize obese patients can reduce unexpected ICU transfers, and 90-day ED visits, readmissions, and reoperations.
Methods
We retrospectively reviewed 1,724 consecutive risk stratified patients undergoing primary unilateral TKA. The mean age was 64.8 years and average body mass index (BMI) was 34.2 kg/m2. All patients underwent preoperative optimization using the RST. We first compared our primary variables of interest between obese (BMI>30, n=1,189) and non-obese patients (n=535). Patients were then divided into 3 groups (I-non-obese, II-obese (30–39.9 kg/m2) and III-morbidly obese ((>40 kg/m2)) and logistic regression was used to evaluate outcomes among the groups adjusted for age, sex, smoking history and diabetes.
Introduction
Perioperative optimization efforts have improved outcomes following primary total knee arthroplasty (TKA). However, morbidly obese patients continue to have increased rates of complications. The purpose of this study was to assess if rates of early complications after TKA have similarly improved for both morbidly obese and non-morbidly obese patients.
Methods
Elective, primary TKA patients from 2011–2018 were identified in the National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 kg/m2 and ≥40 kg/m2. Thirty-day rates of infectious complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between BMI groups utilizing odds ratios (OR) and multivariate analyses.
Introduction
Implementing operative eligibility thresholds based on body mass index (BMI) alone risks restricting access to improved pain, function, and quality-of-life. The purpose of this study was to: 1) investigate the relationship between BMI and improvements in 1-year patient reported outcome measures (PROMs), and 2) determine how many patients would have been denied 1-year improvements with specific BMI cut-offs.
Methods
Data were collected on a prospective cohort of 3,214 TKA patients from 2015–2018. Clinically meaningful 1-year improvements were defined as 15 points for Knee Injury and Osteoarthritis Outcome Scores (KOOS) pain and Physical Function Shortform (PS), and 14 points for Knee-Related Quality-of-Life (KRQOL). For specific BMI cut-offs, the positive predictive value for predicting a failure to improve and number of patients denied surgery to avoid one failed improvement was calculated.
Introduction
Topical diclofenac has proven efficacy and safety in the management of osteoarthritic pain. Its therapeutic efficacy is dependent on its ability to deliver pharmacodynamically active concentrations to the underlying tissues in the affected joint. However, the disposition of topical diclofenac is not fully characterized, and no studies have been performed using diclofenac diethylamine 2.32% gel.
Methods
This study investigated the penetration of topical diclofenac into knee synovial tissue and fluid and evaluated relative exposure in the knee versus plasma. In this phase 1, double-blind, placebo-controlled steady-state multicenter pharmacokinetic study, patients scheduled for arthroplasty to treat knee OA were randomly assigned 2:1 to 4 g diclofenac/placebo gel, applied to the affected knee every 12 hours for 7 days pre-surgery. Diclofenac concentrations were measured in synovial tissue, fluid, and plasma ≥12 hours after last application. Adverse events (AEs) were evaluated. Diclofenac concentrations were assayed by validated high-performance liquid chromatography and tandem mass spectrometry.
Introduction
The use of intraoperative liposomal bupivacaine (LB) peri-articular injection has been highly debated for total knee arthroplasty (TKA). We evaluated the effect of an institutional-wide discontinuation of intraoperative LB on immediate postoperative pain scores, opioid consumption, and objective functional outcomes.
Material and Methods
Between July 1, 2019 and November 30, 2019, an institutional policy discontinued use of intraoperative LB, while the volume of non-LB with epinephrine was increased from 40-ml to 60-ml. A historical cohort was derived from patients undergoing TKA between January 1, 2019 and June 30, 2019. All patients received the same opioid sparing protocol, minimizing variability in prescribing habits. No adductor canal blocks/pumps were utilized.
Nursing documented verbal rating scale (VRS) pain scores were collected from our electronic data warehouse and averaged per patient per 12-hour interval. Opiate administration events were derived as Morphine Milligram Equivalences (MMEs) per patient per 24-hour interval. To assess immediate postoperative functional status, the validated Activity Measure for Post-Acute Care (AM-PAC) tool was utilized. All time events were calculated relative to TKA completion instant.
Background
Early mobilization after total joint arthroplasty decreases postoperative complications and optimizes future functional outcomes. The purpose of this study was to evaluate the effectiveness of a supervised patient ambulation program following total joint arthroplasty.
Methods
In 2014, our institution initiated a mandatory supervised patient ambulation program termed “No One Walks Alone” (NOWA). The program requires that all patients who mobilize are accompanied by a nurse or physical therapist. Gait belts are worn whenever a patient ambulates. Bed and chair alarms are utilized to alert if a patient tries to ambulate alone. If a patient experiences a fall, he or she is immediately evaluated by the nursing staff, and details regarding the fall and any injury sustained are documented.
A retrospective review of patients undergoing total knee or hip arthroplasty between 2011–2017 was conducted. Patients who had surgery between 2011–2013, before the program, were included in the pre-implementation group (N= 3,069) and those having surgery between 2016–2017, after the program started, were included in the post-implementation group (N=3,947). The incidence of patient falls, fall-related complications were compared between groups.
At our tertiary, large, academic healthcare system, we have access to an academic medical center (AMC), a community based, orthopedic friendly, efficient hospital (CBH) and several ambulatory care centers (ASC) which are being prepared to provide same day discharge (SDD) TJA and UKA. We had a near-capacity AMC with an excellent ability to care for medically and technically complicated TJA patients. However, efficiency was less than desired regardless of case complexity with an average effective case time of 4 hours. Concurrently, the orthopaedically, under-utilized community-based hospital (CBH) wanted to increase volume, improve margins, and become a TJA Center of Excellence with the ability to provide an efficient Hospital Outpatient Department (HOPD) and SDD TJA surgery experience.
Methods
The CBH had a main operating floor and a separate floor of four OR suites which were repurposed with the goal of utilizing these rooms for TJA four days per week with an average of 3.5 cases per room per day. We preferentially performed primary, uncomplicated TJA, UKA, and minimally invasive TJA at the CBH. Revision surgeries, patients with extensive medical comorbidities, and complex primary surgeries would be performed at the AMC. Our goals were to decrease costs, readmissions, length of stay, and increase margins at the CBH while increasing efficiency, revenue and volume. Protocols were developed to facilitate SDD UKA and THA at both hospitals as well as rapid recovery protocols for TKA at both hospitals with the understanding that the CBH would perform more of these cases but the efficiency could also be implemented at the AMC when possible. We also needed a strategy to deal with TKA and eventually THA being removed from the Inpatient Only (IPO) list. CMS has utilized the “Two-Midnight Rule” to define outpatient status for both THA and TKA. This has distinct financial implications for the facility's reimbursement with outpatient being $10,123 on average versus $12,380 for inpatient status. A protocol-based system was put in place to make both hospitals compliant with the removal of TKA from the IPO List in order to avoid Quality Improvement Organization (QIO) and Recovery Audit Contractor (RAC) after implementation.
Results
Comparing FY 2018 to FY 2019, volume increased 26.4% at the CBH. Outpatient case volume rose substantially from 14 cases to 243. Volumes were slightly decreased at the AMC (−4.57%) resulting in a substantial increase in margin contribution for the parent enterprise. Quality metrics at the CBH (surgical site infections (SSI), length of stay (LOS), readmissions, and mortality) were improved. LOS improved from 52% to 71% discharge before 48 hours. The LOS decreased 12% for THA and 8.1% for TKA. CBH readmission rates decreased from 1.38% to 0.9% with no deaths. Surgeon satisfaction is greatly improved as their volume, efficiency, quality metrics, and finances were enhanced.
Financial performance was improved in aggregate and per case for the CBH. Although the CBH per-case revenue was 80.3% and 74.4% of the AMC for THA and TKA: the net margins were 3.6% and 18.8% higher for THA and TKA, respectively. The increased efficiency, lower hospital cost and higher volume at the CBH allowed for an increase in revenue despite lower reimbursement per case.
Introduction
Bundled Payments (BP) were a revolutionary new experiment for CMS that tested whether risk sharing for an episode of care would improve quality and reduce costs. The initial success of BP accelerated their growth as evidence by the launch of both mandatory and commercial bundles. Success in BP is dependent on the target price and the opportunity to reduce avoidable costs during the episode of care. There is concern that the aggressive target pricing methodology in the new model (BPCI-Advanced) penalizes high performing groups that already achieved low episode costs through prior experience and investment in BP. We hypothesize that this methodology incorporates unsustainable downward trends on target prices to a point beyond reasonableness for efficient groups to reduce additional costs and will lead to a large percentage of groups opting out of BPCI-A in favor of a return to fee for service (FFS) reimbursement.
Methods
Using CMS data, we compared the target price factors for hospitals that participated in both BPCI classic (2013 –2018) and BPCI Advanced (beginning 10/2018), referred to as “legacy hospitals”, with hospitals that only participated in BPCI Advanced (beginning 10/2018). With the rebasing of BPCI-A target prices in Jan 2020 and the opportunity for participants to drop out of individual episode types or the program all together, we compared the retention of episode types that hospitals initially enrolled at the onset of BPCI-A with the current enrollment in 2020. Locally, we analyzed the BPCI-A target price factors across hospitals for a large orthopaedic practice that participated in BPCI Classic and the impact it had on the financial incentive/disincentive to remain in the lower extremity joint replacement episode type in 2020.
Introduction
Social determinants of health (SDOH) may contribute markedly to the total cost of care (COC) for patients undergoing elective total knee arthroplasty (TKA). This study investigated the association between demographics, health status, and SDOH on lengths of stay (LOS) and 30-day COC.
Methods
Patients who underwent TKA between January 2018 and December 2019 were identified. Those who had complete SDOH data were utilized, leaving 234 patients. Data elements were drawn from the Chesapeake Regional Information System, the Center for Disease Control social vulnerability index (SVI), the Food Access Research Atlas (FARA). The SVI identifies areas vulnerable to catastrophic events, with 4 themed scores including: (1) socioeconomic status; (2) household composition and disability; (3) minority status and language; and (4) housing and transportation. Food deserts were defined as neighborhoods located 1 or 10 miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine an association with LOS and cost, after controlling for demographics.
Introduction
The Center for Medicare and Medicaid Services (CMS) is faced with a challenge of decreasing the cost of care for total knee arthroplasty (TKA), but must make efforts to prevent patient selection bias in the process. Currently, no appropriate modifier codes exist for primary TKA based on case complexity. We sought to determine differences in perioperative parameters for patients with “complex” primary TKA with the hypothesis that they would require increased cost of care, prolonged care times, and have worse postoperative outcome metrics.
Methods
We performed a single center retrospective review from 2015 to 2018 of all primary TKA. Patient demographics, medial proximal tibial angle (mPTA), lateral distal femoral angle (lDFA), flexion contracture, cost of care, and early postoperative outcomes were collected. ‘Complex’ patients were defined as those requiring stems or augments, and multivariable logistic regression analysis and propensity score matching were performed to evaluate perioperative outcomes.
Introduction
Instability following total knee arthroplasty is a leading cause of failure and is often treated with component revision. The goal of this study was to determine if isolated tibial polyethylene insert exchange (ITPIE) to a higher-level constraint would afford similar outcomes to component revision in the properly selected patient.
Methods
We retrospectively evaluated 176 consecutive patients between 2016–2017 who were revised for symptomatic instability at a single institution. Demographic information and level of constraint preoperatively and postoperatively were documented. Radiographic parameters were also recorded for patients undergoing ITPIE. Outcome measures included all cause re-revision rates as well as patient reported outcome measures (PROMs) obtained preoperatively and at minimum 1-yr follow up. Descriptive analysis including sample t-test and chi square test were performed with statistical significance set at p <0.05.
Introduction
Total knee arthroplasty (TKA) femoral components are known to wear and roughen with clinical use, and reaction to metal is a well-documented complication of TKA. Ceramic materials are resistant to wear and corrosion, but the surface wear of ceramic femoral components in TKA has not been reported. This study measured the changes in roughness and mass lost from cobalt-chromium (CoCr) femoral components tested in a knee simulator, and compared them to those observed in ceramic components.
Methods
Six cast CoCr femoral components were tested in a knee simulator bearing against UHMWPE, with high-kinematics/high-load waveforms. Roughness and scratches were measured via optical profilometry. Scratch volume was equated to mass lost from abrasive wear, while nano-particulate wear and corrosion were estimated from the change in the distance of the surface to the depth of the scratches after increasing numbers of cycles. Three magnesia-stabilized zirconia femoral components that had been wear tested to 15 million cycles were compared with the CoCr components.
Background
A limited number of investigations with conflicting results have described perivascular lymphocytic infiltration (PVLI) in the setting of total knee arthroplasty. The purpose of this study was to determine if PVLI found in total knee replacements at the time of aseptic revision surgery was associated with worse clinical outcomes and survivorship.
Methods
A retrospective review was conducted on 617 patients that underwent aseptic total knee arthroplasty revision who had histologic analysis for PVLI at the time of surgery. Clinical and radiographic data was obtained pre and postoperatively, 6 weeks post operatively, and then every year thereafter.
Introduction
Mechanical or corrosive failure of total knee arthroplasties (TKAs) is difficult to diagnose with current laboratory and radiographic analyses. As such, the goal of this study was to determine the mean blood concentration of cobalt, chromium, and titanium in a series of revision TKAs with mechanical implant failure and evaluate whether they facilitated identification of the underlying TKA failure mechanism.
Methods
Serum cobalt, chromium, and titanium levels and synovial fluid characteristics were evaluated in 12 patients (13 aseptic revision TKAs) who underwent revision TKA between 2000 and 2020 at a single academic institution for mechanical implant failure or corrosion. Seventy-five percent were re-revisions of previously revised TKAs. Mean time to revision was 6 years. Modular metallic junctions were present in 100%. Twenty-five percent did not have another
Introduction
One of the main considerations in the revision TKR setting is deciding on the level of constraint to be utilized once the bone defects have been reconstructed. There is a fear that employing a maximally constrained insert could compromise long term results. We report on a consecutive series of full tibial and femoral component revisions all treated with a maximally conforming insert and followed for a minimum of 5 years.
Materials and Methods
The study group consisted of 76 consecutive revision TKR in 76 patients where both the femur and the tibia were revised. 4 patients died and 6 were lost to follow up. Final cohort had an average age of 70 years, average BMI of 31 and there were 39 males in the group. Average time to revision was 7 years (range 1–10 years) and the reasons for revision included infection in 28, aseptic loosening 26, osteolysis and poly wear in 9 and 13 other. All were treated with the same revision system and an identical maximally conforming tibial rotating platform insert and followed for an average of 7 years (range 5–14 years).
Introduction
Revision total knee arthroplasty (TKA) is becoming increasingly common in the United States as the population ages and larger numbers of primary TKA are performed in younger individuals. Cemented or uncemented tibial stems are frequently used in revision cases. Decreased clinical outcomes and patient satisfaction have been described for revision TKA. This study aims to determine if the presence of overall pain and tibial pain at the end of the stem differs between cemented and uncemented tibial stems in revision TKA.
Methods
This was a retrospective cohort study comparing patients who underwent revision TKA utilizing cemented or uncemented tibial stems in a 15-year period at a single institution with at least two-year follow-up. Exclusion criteria included age under 18, isolated revisions of the femoral component or polyethylene exchanges, lack of preoperative or postoperative imaging, insufficient operative or implant records available for electronic chart review, revision procedures performed at outside facilities, patients who were deceased at the time of survey administration, refusal to participate in the study, and failure to return the mailed survey or respond to a telephone follow-up questionnaire. Radiographic analysis included calculation of the percentage of the tibial canal filled with the implant, as well as measurement of the diameter of the tibial stem. Radiographs were also reviewed for evidence of cavitary defects, pedestal formation, radiolucent lines, and periprosthetic fractures. Mailed surveys addressing overall pain, tibial pain, and satisfaction were analyzed using Fisher's exact test and the independent sample t-test. Logistic regression was used to adjust for age, gender, and preoperative bone loss.
Introduction
Tibial cones are often utilized in revision total knee arthroplasty (TKA) with metaphyseal defects. However, there are few studies evaluating outcomes out to five years with a sufficient cohort. The purpose of this study was to evaluate implant survivorship and complications in revision TKAs with tibial cones.
Methods
A retrospective review was completed from September 2006 through March 2018 evaluating 149 revision TKAs that received a tibial cone. The mean follow-up was 5.3 years. According to the AORI classification: 8% were 1, 18% were 2A, 55% were 2B, and 19% were 3.
Introduction
Porous metaphyseal cones are increasingly used for fixation in revision total knee arthroplasty (RTKA). Both cemented shorter length stems and longer diaphyseal engaging stems are currently utilized with metaphyseal cones with no clear evidence of superiority. The purpose of this study was to evaluate our experience with 3D printed titanium metaphyseal cones with both short cemented and longer cementless stems from a clinical and radiographic perspective.
Methods
In total 136 3D printed titanium metaphyseal cones were implanted. The mean patient age was 63 and 48% were female. The mean BMI was 33 and the mean ASA class was 2.5. There were 42 femoral cones in which 28 cemented and 14 cementless stems were utilized. There were 94 tibial cones in which 67 cemented and 27 cementless stems were utilized. The choice for stem fixation was surgeon dependent and in general cones were utilized for AORI type 2 and 3 bone defects on the femur and tibia. The most common fixation scenario was short cemented stems on both the femur and tibia followed by cemented stem fixation on the tibia and cementless fixation on the femur. Clinical data such as revision, complication, and PRO was collected at last follow-up (minimum follow-up 1 year). Radiographic analysis included cone bony ingrowth and coronal and sagittal alignment on long-standing radiographs. Descriptive statistics were used to compare demographics between patients who had malalignment (HKA beyond +/− 3 degrees and flexion/extension beyond +/− 3 degrees). Adjusted logistic regression models were run to assess malalignment risk by stem type.
Introduction
Previous studies have demonstrated that higher volume hospitals have better outcomes following revision total knee arthroplasty (rTKA), in current literature there are no reports investigating the effect of surgeon volume. The purpose of this study is to investigate if patients of high-volume revision surgeons have better outcomes following rTKA as compared to patients of low volume surgeons.
Methods
This retrospective observational analysis examined the rTKA database at a large urban academic medical center for aseptic, unilateral rTKA between January 2016 and March 2019 with at least 1-year of follow-up. Surgeon operative volume during the same time period was evaluated. Surgeons who performed at least 18 aseptic rTKA per year were considered
Background
Revision total knee arthroplasty (rTKA) is a complex procedure with increased risk of blood loss and transfusions. The Musculoskeletal Infection Society has included D-dimer as a serology marker for peri-prosthetic infection. The study's intent is to understand the impact of preoperative D-dimer levels on blood loss and venous thromboembolism in revision TKA.
Methods
Following IRB approval, rTKA performed by a single surgeon between January 1, 2017 and December 31, 2019 were reviewed. Inclusion criteria consisted of pre-operative D-Dimer, cemented revision TKA of one or both components under tourniquet control. 89 patients met the criteria including 37 males (41.6%) and 52 females (58.4%). Mean ages were 65 for males and 67 for females. The data revealed 54 patients (61%) had an elevated D-dimer (group 1) and 35 patients (39%) had a normal D-dimer (group 2). Sex stratification showed 21 males (57.8%) and 33 females (63.5%) with elevated D-dimer. TXA protocol included 2 grams intravenous (82 patients) or 2 grams intra-articular application (7 patients). Post-operative anticoagulation included Lovenox 40mg daily for 2 weeks followed by aspirin 325 twice daily for 4 weeks. Pre-operative and post-operative hemoglobin, transfusion rates and post-operative VTE within 90 days of surgery were recorded.
Introduction
Pitting damage on implants has been reported and attributed to use of electrocautery. This study aimed to distinguish how different TKA bearing surfaces are susceptible to this type of damage and whether surgeons were aware that this damage can occur.
Methods
A survey was sent to Hip and Knee Society members to determine what percentage of adult reconstructive surgeons use electrocautery after implantation of components. Three bearing surfaces for primary TKA were selected: CoCr, Oxinium, and zirconium nitride (ZrN) to be damaged by electrocautery with a monopolar (MP, Bovie) and bipolar (BP, Aquamantys) electrocautery with three different energy settings. A comparison of surface damage and backscatter elemental analysis using SEM was performed. Average roughness (Ra), maximal peak-to-valley height (Rz,), kurtosis (Rk), and skewness (Rsk) measurements were collected using a profilometer (DektakXT, Bruker, Tucson, AZ) with a 2.5µm radius stylus to assess an area of 3.8mm by 3.2mm in the central portion of the area for each MP and BP energy setting used to impart damage to the bearing surfaces. A similar undamaged area for each bearing surface was also measured for roughness parameter comparison.
Introduction
Our study aimed to correlate Forgotten Joint Socre(FJS) preoperatively(Preop-FJS) and postoperatively(Postop-FJS), hypothesis being that patients with high Preop-FJS had more likelihood of poor Postop-FJS.
Material & Methods
We retrospectively identified 212 patients, having undergone uniform primary TKA by a single surgeon over 20 months, with complete data of FJS and New Knee Society Score (NKSS), recorded preoperatively and postoperatively(1year±1month). Mean age was 66.3 years, with 167 female and 45 males.
We correlated Preop-FJS to Postop-FJS using Spearmans correlation test. For our hypothesis, we studied patients using two cutoffs for Preop-FJS, first set with median Preop-FJS cutoff of 35 and second set with median Preop-FJS cutoff of 40. We applied Mann Whitney U test to compare Postop-FJS. SPSS software V15.0 was used.
Introduction
Patient satisfaction is an important outcome measure after total knee arthroplasty (TKA) and is the ultimate goal of surgery. However, patient satisfaction reflects a complex construct of the patient's personal expectations and preferences in addition to subjective evaluation of outcome after TKA. Multiple studies have found a patient dissatisfaction rate of approximately 20% at 1 year after TKA. The purpose of this study is to determine whether there is an association between a single-item validated TKA satisfaction score and patient-reported outcome measures (PROMs) at 3 time points (1, 2, and 5 years after TKA) and to determine if dissatisfaction rate after TKA varies over time.
Methods
A multi-center, prospective cohort of 12,952 patients (8,078 patients were assessed at 1-year, 702 patients at 2-year, and 4,172 patients at 5-year) undergoing primary TKA were enrolled by 230 surgeons in 28 states between 2012–2015. Surgeons practices varied in size, reimbursement models, and geographic setting ensuring that the cohort included diverse patient populations and delivery models. Surgeons agreed to invite all TKA patients to participate and sporadic audits of surgical logs validated that all patients were invited and > 90% of patients were included. Demographic and clinical data [age, gender, body mass index (BMI), and modified Charlson co-morbidity index (CCI)] were collected. Patient-reported outcome measures (PROMs) were collected pre-op and post-op at 1, 2, and 5 years using an internet-based platform including the KOOS (total score, and pain, ADL, QoL sub scores), KOOS Jr, SF-36 (PCS and MCS). We used the single-item satisfaction scale which was tested and validated by the Swedish Knee Arthroplasty Registry. The patients' responses were made on 5-point Likert scale (very satisfied, somewhat satisfied, neutral, somewhat dissatisfied, very dissatisfied). Patients were classified into 2 categories: satisfied group for patients who answered satisfied or very satisfied and dissatisfied group for patients answered neutral, somewhat dissatisfied, or very dissatisfied. Univariate analysis of the difference between the satisfied and dissatisfied patients' groups was performed using Mann-Whitney U test for continuous variables and chi-square test for categorical variables. Logistic regression model was performed to study the correlation between the satisfaction and PROMs with 95% confidence interval.
Introduction
Unexpected cancellation of scheduled total joint arthroplasty (TJA) procedures create patient distress and are disruptive to the clinical team. The purpose of this study was to identify the etiology of cancellation for scheduled TJA and to determine the subsequent fate of those patients.
Methods
A consecutive series of 11670 primary THA and TKA patients at a single institution was reviewed from January 2013 through March 2017. All patients who were scheduled for a primary THA or TKA and subsequently cancelled were identified. The etiology of cancellation and time to rescheduling were recorded. Univariate analysis and cox regression models were performed.
Introduction
The effect of using thicker liners in primary total knee arthroplasty (TKA) on functional outcomes and aseptic failure rates remains largely unknown. As such, we devised a multicenter study to assess both the clinical outcomes and survivorship of thick vs thin liners after primary TKA.
Methods
A search of our institutional databases was performed for patients having undergone bilateral (simultaneous or staged) primary TKA with similar preoperative and surgical characteristics between both sides. Two cohorts were created: thick liners and thin liners. Outcomes collected were as follows: change in Knee Society Score (DKSS), change in range of motion, and aseptic revision. Ad hoc power analysis was performed for DKSS (α ¼ 0.05; power ¼ 80%). Differences between cohorts were assessed.
Introduction
In total knee arthroplasty (TKA), tibial insert thickness is determined intraoperatively by applying forces that generate varus-valgus moments at the knee and estimating the resulting gaps. However, how the magnitude of applied moments and the surgeon's perception of gaps affect the thickness selection is unclear. We determined this relationship using an in vitro human cadaveric model.
Methods
Six pelvis-to-toe specimens (72±6 years old, four females) were implanted by an expert surgeon with a PS TKA using measured resection. Pliable sensors were wrapped around medial and lateral aspects of the foot and ankle to measure the applied forces. The forces were scaled by limb length to obtain the moments generated at the knee. Six surgeons with different experience levels independently assessed balance by applying moments in extension and 90° of flexion and choosing the insert they believed fit each knee. Peak moments and the accompanying extension and flexion gap openings as perceived by surgeons were recorded. The two measures were then related to insert choice using a generalized estimating equation.
Introduction
Malalignment of total knee arthroplasty components may affect implant function and lead to decreased survival, regardless of preferred alignment philosophy – neural mechanical axis restoration or kinematic alignment. A common technique is to set coronal alignment prior to adjusting slope. If the guide is not maintained in a neutral position, adjustment of the slope may alter coronal alignment. Different implant systems recommend varying degrees of slope for ideal function of the implant, from 0–7°. The purpose of this study was to quantify the change in coronal alignment with increasing posterior tibial slope comparing two methods of jig fixation.
Methods
Prospective consecutive series of 100 patients undergoing total knee arthroplasty using computer navigation. First cohort of 50 patients had extramedullary cutting jig secured distally with ankle clamp and proximally with one pin and a second cohort of 50 patients with the jig secured distally with ankle clamp and proximally with two pins. The change in coronal alignment was recorded with each degree of increasing posterior slope from 0–7° using computer navigation. Mean coronal alignment and change in coronal alignment was compared between the two cohorts.
Introduction
Mechanical axis limb alignment in total knee arthroplasty (TKA) has demonstrated excellent long-term survivorship; however, patient satisfaction continues to demand improvement. Alternative emerging alignment concepts including kinematic and tibial constitutional varus have been introduced but remain controversial. The purpose of this study was to evaluate outcomes and patient satisfaction following TKA with tibial components placed in constitutional varus alignment.
Methods
This was a retrospective cohort analysis from a total joint registry of 114 patients with preoperative varus deformity who underwent primary TKA with tibial component placed in 1–3 degrees of constitutional varus. The group included 59 males (52%) and 55 (48%) females with a mean age of 67 years (range 43 – 85) and mean BMI of 32.0 kg/m2 (range 21 – 51 kg/m2) with a minimum 1 year follow-up. Patients were stratified into 3 groups based on the preoperative varus alignment: Group A between 1°- 5° varus (43 knees), Group B between 6°- 10° (56 knees), and Group C greater than 10° (16 knees). The target constitutional tibial varus alignment was selected based on the extent of the patient's deformity.
Introduction
Recent total knee arthroplasty (TKA) designs have featured more anatomic morphologies and shorter tibial keels. However, several reports have raised concerns regarding the impact of these modifications on implant longevity. This study's purpose is to report the early performance of a modern, cemented TKA design.
Methods
All patients who received a primary, cemented TKA from 2012 to 2017 with a minimum two-year follow-up were included. This implant features an asymmetric tibial baseplate and a shortened keel. Patient demographics, Knee Society Scores (KSS), and component alignment were recorded, and Kaplan-Meier survivorship analyses were performed.
Background
There are case series of debonding of the ATTUNE® tibial component introduced in 2013. We studied the early clinical results of this total knee arthroplasty (TKA) and compared it to other designs at one hospital.
Methods
This is a retrospective study of 223 consecutive, non-randomized, cemented fixed-bearing posterior-stabilized ATTUNE® TKAs at one hospital by 5 surgeons from 2013 through 2017. We excluded 4 knees with early infection and 53 with follow-up less than 6 months. Of 166 TKAs reviewed, the mean patient age was 63.8 years, mean BMI 32, and mean follow-up 25 months. We compared this to a “control” cohort of 511 TKAs of other manufacturers performed at the same hospital. The endpoints were revision performed and revision pending.
Introduction
The American Joint Replacement Registry (AJRR) is the largest registry of total hip and knee arthroplasty (THA and TKA) procedures performed in the U.S. The National (Nationwide) Inpatient Sample (NIS) is a public database containing demographic estimates based on more than seven million hospitalizations annually. The purpose of this study was to analyze whether AJRR data is representative of the national experience with TJA as represented in NIS
Methods
Cohen's d effect sizes were computed to ascertain the magnitude of differences in demographics, hospital volume (in 50 patient increments), and geographic characteristics between the AJRR and NIS databases.
Introduction
Bone mineral density (BMD) is correlated with component migration and aseptic loosening after total knee arthroplasty (TKA). Older implant designs have demonstrated BMD loss up to 23% in the first 6 months after TKA, and continued to BMD decline at an average of 5% per year for as long as 2 years after TKA. The impact of component design and fixation method on BMD loss after TKA in modern implant designs has not been fully elucidated. The purpose of this study is to determine the effect of tibial tray thickness and fixation method (cemented versus cementless) on BMD loss patterns of the proximal tibia in two different modern TKA implant systems
Methods
A prospective, nonrandomized, single center study of patients undergoing primary TKA by one of two surgeons was performed with four study cohorts: cemented DePuy Attune, cementless DePuy Attune, cemented Stryker Triathlon, cementless Stryker Triathlon. Target sample size was 80, with 20 per cohort based on adhoc power analysis. Exclusion criteria included: age over 75, BMI >40, inflammatory arthritis, previous knee surgery involving the femur, tibia or tibial bone, and diagnosis of osteopenia/osteoporosis. Implant fixation type was based on surgeon intraoperative assessment of patient bone quality. Demographic data was collected preoperatively. Dual Energy X-ray Absorptiometry (DEXA) Bone Density Monitoring was performed at 6 weeks and one year postoperatively. Bone mineral density was calculated from the DEXA scans for 4 zones for the tibia relative to the keel or central peg: anterior, posterior, medial and lateral. Results were reported as BMD at 1 year postoperatively as a percentage of BMD at 6 weeks postoperatively.
Introduction
Initial post-operative implant instability leads to impaired osseointegration, one of the most common reasons for aseptic loosening and revision surgery. In this study, we developed a novel murine model of implant instability and demonstrated the anabolic effect of immediate and delayed intermittent Parathyroid Hormone (iPTH) treatment in the setting of instability-induced osseointegration failure.
Methods
3D-printed titanium implants were inserted in an oversized drill-hole in the tibia of C57Bl/6 mice (n=54). After implantation, the mice were randomly divided in 3 treatment groups (control: PBS-vehicle; iPTH; delayed iPTH). Radiographic analysis was performed to confirm signs of implant loosening. Peri-implant tissue formation was assessed through histology. Osseointegration was assessed through µCT and biomechanical pullout testing.
Introduction
Cementless TKA offers the potential for strong fixation through biologic fixation technology as compared to cemented TKA where fixation is achieved through mechanical integration of the cement. Few mid-term results are available for newer cementless TKA designs that have used additive manufacturing (3-D printing) for component design. The purpose of this study is to present minimum 5-year clinical outcomes and implant survivorship of a specific cementless TKA using a novel 3-D printed tibial baseplate.
Methods
This is a single institution registry review of the prospectively obtained data on 296 cementless TKA using a novel 3-D printed tibial baseplate with minimum 5-year follow-up. Outcomes were determined by comparing pre- and post-operative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores and pre- and post-operative 12 item Veterans RAND/Short Form Health Survey (VR/SF-12). Aseptic loosening as well as revision for any reason were the endpoints used to determine survivorship at 5 years.
Background
In recent years, the use of modern cementless implants in total knee arthroplasty has been increasing in popularity. These implants take advantage of new technologies such as additive manufacturing and potentially provide a promising alternative to cemented implant designs. The purpose of this study was to compare implant migration and tibiofemoral contact kinematics of a cementless primary total knee arthroplasty (TKA) implanted using either a gap balancing (GB) or measured resection (MR) surgical technique.
Methods
Thirty-nine patients undergoing unilateral TKA were recruited and assigned based on surgeon referral to an arthroplasty surgeon who utilizes either a GB (n = 19) or a MR (n = 20) surgical technique. All patients received an identical fixed-bearing, cruciate-retaining beaded peri-apatite coated cementless femoral component and a pegged highly porous cementless tibial baseplate with a condylar stabilizing tibial insert. Patients underwent a baseline radiostereometric analysis (RSA) exam at two weeks post-operation, with follow-up visits at six weeks, three months, six months, and one year post-operation. Migration including maximum total point motion (MTPM) of the femoral and tibial components was calculated over time. At the one year visit patients also underwent a kinematic exam using the RSA system.
Introduction
The ideal type of total knee arthroplasty (TKA) prosthesis remains a debatable topic with many different options available. Uncemented TKA has been a viable option due to its decreased operating room (OR) time but also because of its proposed improved long term fixation. Unfortunately, in the past uncemented TKA was associated with increased blood loss. Surgical technique and perioperative treatments have changed since these original studies and tranexamic acid (TXA) has become the gold standard for TKA blood loss management. The objective of this study was to evaluate if there was a difference in hemoglobin and hematocrit change, along with blood loss volume during surgery between cemented and cementless TKA when modern blood loss techniques are utilized
Methods
We retrospectively reviewed data from TKAs performed by three high volume surgeons between 2016 and 2019. We excluded bilateral TKA, revisions, hardware removal intraoperatively and other indications for TKA than primary OA. Power analysis determined 85 patients in both the cementless and cemented TKA groups. Patients were matched 1:1 for age, sex, BMI and surgeon. Use of TXA, intraoperative blood loss, differences in hemoglobin and hematocrit pre- and postoperatively days one, two, and three were recorded. Continuous variables were analyzed using T-tests and categorical variables were evaluated using Chi-squared tests.
Background
Secondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients in their working years; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of cemented TKA with/without patellar resurfacing for SOK.
Methods
Thirty-eight cemented TKAs in 27 patients with non-traumatic SOK with a mean age 43 years (range 17–65) were retrospectively reviewed. Twenty-one patients (78%) were female. Mean body mass index was 31 kg/m2 (range 20–48); 11 patients (41%) received bilateral TKAs. Twenty patients (74%) had a history of corticosteroid use and 18% had a history of alcohol abuse. Patellar osteonecrosis was coincidentally found in six knees (16%), all of which had no anterior knee pain and had no patellofemoral joint collapse. The mean follow-up was 7 years (range 2–12). Knee Society Score (KSS) and radiographic outcomes were evaluated at 6 weeks, 1 year, then every 2–3 years thereafter.
Introduction
Bilateral TKA is proven to be safe in a select group of patients. Patients with symptomatic bilateral knee arthritis who are not candidates for simultaneous bilateral TKA are subjected to staged surgery. The main objective of this study is to determine the safe window when second TKA can be performed in patients requiring bilateral TKA
Methods
Retrospective study includes bilateral TKA cases performed in a single institution between 2000–2018. A cohort of simultaneous bilateral TKA (n=2728) was compared to cohort of staged bilateral TKA (n=1660). Outcomes in terms of complications, reoperation, 30 days readmission and cumulative revision rates were compared between the two groups using both non-adjusted and adjusted models.
Introduction
A large proportion of patients undergoing total knee arthroplasty (TKA) have severe osteoarthritis in both knees and may consider either simultaneous or staged bilateral TKA. The implications of staged versus simultaneously bilateral TKA for return to work are not well understood. We hypothesized that employed patients who underwent simultaneous bilateral TKA would have significantly fewer days missed from work compared to the sum of days missed from each surgery for patients who underwent staged bilateral TKA.
Methods
The prospective arthroplasty registry at Hospital for Special Surgery was utilized. We identified 61 employed patients who had undergone staged bilateral TKA and 152 employed patients who had undergone simultaneous bilateral TKA and had completed the registry's return to work questionnaire. Baseline characteristics and patient reported outcome scores were evaluated. We used a linear regression model, adjusting for potential confounders including age, sex, pre-op BMI, and work type (sedentary, moderate, high activity, or strenuous), to analyze workdays lost after staged versus simultaneous bilateral TKA.
